JP2010216685A - Heat pump system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat pump system capable of improving cycle efficiency in the processing of a heat load by a secondary refrigerant. <P>SOLUTION: A heat pump circuit 10 in which a carbon dioxide refrigerant is made to circulate includes a low-stage side compressor 21, a high-stage side compressor 25, an expansion valve 5 and an evaporator 4. A heating circuit 60 in which water as the secondary refrigerant is made to circulate includes a radiator 61. The heating circuit in which water as a heat medium for heating is made to circulate includes an intermediate-pressure side branch path 67 and a high-pressure side branch path 68 which are arranged in parallel with each other. A control section 11 operates a heating mixing valve 64 so that the temperature of the secondary refrigerant in a portion of the intermediate-pressure side branch path 67 heated by an intermediate-pressure water heat exchanger 40 becomes equal to the temperature of the secondary refrigerant in a portion of the high-pressure side branch path 68 heated by a second high-pressure water heat exchanger 52. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a heat pump system.

  Conventionally, a system that performs a heating operation using a heat pump cycle in which a primary refrigerant circulates and a secondary side cycle in which a secondary refrigerant circulates is known.

  For example, in a heat pump type air conditioner described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2004-177067), a high-pressure side primary refrigerant and a low-pressure side primary refrigerant are heat-exchanged to warm the low-pressure side primary. Efficiency is improved by assisting heating of the secondary refrigerant for heating using the heat of the refrigerant.

  Since the heat pump type air conditioner described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2004-177067) assumes a single-stage compression type with only one compression mechanism, the driving force required in the compression mechanism Has increased.

  The subject of this invention is providing the heat pump system which can improve cycle efficiency in the process of the heat load by a secondary refrigerant.

  The heat pump system of the first invention includes a heat pump circuit, a first heat load circuit, a first heat exchanger, a second heat exchanger, a first flow rate adjusting mechanism, and a control unit. The heat pump circuit has at least a low-stage compression mechanism, a high-stage compression mechanism, an expansion mechanism, and an evaporator. In this heat pump circuit, the primary refrigerant circulates. The first heat load circuit includes a first branch portion, a second branch portion, a first branch path, a second branch path, and a first heat load processing section. The first branch path connects the first branch portion and the second branch portion. The second branch path connects the first branch portion and the second branch portion without joining the first branch path. In the first heat load circuit, the first fluid circulates. The first heat exchanger performs heat exchange between the primary refrigerant that flows from the discharge side of the low-stage compression mechanism toward the suction side of the high-stage compression mechanism and the first fluid that flows through the first branch path. Make it. The second heat exchanger exchanges heat between the primary refrigerant that flows from the high-stage compression mechanism toward the expansion mechanism and the first fluid that flows through the second branch path. The first flow rate adjusting mechanism is capable of adjusting at least one of the flow rate of the first fluid in the first branch path and the flow rate of the first fluid in the second branch path. The control unit performs flow rate adjustment control for operating the first flow rate adjustment mechanism. In this flow rate adjustment control, the temperature of the first fluid that flows through the portion of the first branch passage that has passed through the first heat exchanger, and the first fluid that flows through the portion of the second branch passage that has passed through the second heat exchanger. And the temperature of the first fluid flowing through the portion of the first branch passage that has passed through the first heat exchanger so as to maintain a state satisfying a predetermined temperature condition including a case where the ratio is 1 The first flow rate adjusting mechanism is operated so as to reduce the difference between the temperature of the first fluid flowing through the portion of the second branch passage that has passed through the second heat exchanger. Note that a compression mechanism may be further provided in addition to the high-stage compression mechanism and the low-stage compression mechanism, and the case where a multistage compression system is used is naturally included in the scope of the present invention.

  In this heat pump system, when the amount of heat of the secondary refrigerant supplied to the first heat load processing unit is the same, the difference between the temperature of the first fluid heated by the first heat exchanger and the ambient temperature, and the second heat exchange Any difference between the temperature of the first fluid heated by the vessel and the ambient temperature can be prevented from becoming large. For this reason, the loss of heat released before reaching the first heat load treatment unit of the first fluid heated by the first heat exchanger and the first of the first fluid heated by the second heat exchanger It becomes possible to keep the total of the heat dissipation loss released before reaching the heat load processing unit small. Thereby, it becomes possible to improve the processing efficiency by the heat pump system of the heat load in the first load heat exchanger.

  The heat pump system according to a second aspect is the heat pump system according to the first aspect, wherein the temperature of the primary refrigerant flowing into the first heat exchanger is equal to or higher than the temperature of the first fluid flowing into the first heat exchanger. The temperature of the primary refrigerant flowing into the first heat exchanger while the temperature of the primary refrigerant flowing into the second heat exchanger is equal to or higher than the temperature of the first fluid flowing into the second heat exchanger. The low-stage compression mechanism and the high-stage compression mechanism are such that both the temperatures of the primary refrigerant flowing into the second heat exchanger are equal to or higher than the temperature corresponding to the first heat load required in the first heat load processing unit. Control the output of.

  In this heat pump system, the temperature of the first fluid can be reliably increased by the primary refrigerant flowing into the first heat exchanger without lowering the temperature of the first fluid flowing into the first heat exchanger. And it can prevent that the discharge refrigerant | coolant temperature of a high stage side compression mechanism raises abnormally. Similarly, the temperature of the first fluid can be reliably increased by the primary refrigerant flowing into the second heat exchanger without lowering the temperature of the first fluid flowing into the second heat exchanger. And it becomes possible to respond | correspond to the heat load in a 1st load heat exchanger only by the calorie | heat amount which a 1st fluid acquires in a 1st heat exchanger and a 2nd heat exchanger.

  A heat pump system according to a third aspect is the heat pump system according to the second aspect, wherein the first thermal load circuit includes a portion between the first thermal load processing unit and the first branch portion, a first thermal load processing unit, and a second branch portion. And a first thermal load bypass flow rate adjustment mechanism capable of adjusting the flow rate of the first fluid passing through the first thermal load bypass circuit. In the flow rate adjustment control, the control unit is a target value of the temperature of the first fluid flowing through a portion of the first branch path that has passed through the first heat exchanger and a portion of the second branch path that has passed through the second heat exchanger. Control is performed so that the target value of the temperature of the first fluid flowing through the temperature exceeds the temperature corresponding to the first heat load. The control unit operates the first thermal load bypass flow rate adjustment mechanism to operate the first thermal load bypass circuit so that the temperature of the first fluid supplied to the first thermal load processing unit becomes a temperature corresponding to the first thermal load. The flow rate of the first fluid passing through is adjusted.

  In this heat pump system, not only the temperature of the first fluid flowing through the portion of the first branch passage that has passed through the first heat exchanger but also the first fluid that flows through the portion of the second branch passage that has passed through the second heat exchanger. Even in an operating situation where any of the temperatures exceeds the temperature corresponding to the first heat load required in the first heat load processing unit, the first heat load bypass flow rate adjusting mechanism causes the first heat to flow. By adjusting the flow rate of the first fluid passing through the load bypass circuit, it is possible to adjust the temperature of the first fluid supplied to the first thermal load processing unit. Thereby, in order to raise the efficiency of a heat pump circuit, the part which passed the 2nd heat exchanger among the temperature of the 1st fluid which flows through the part which passed the 1st heat exchanger among the 1st branch, and the 2nd branch Even if the temperature of the first fluid flowing through the first temperature may exceed the temperature corresponding to the first heat load, the temperature of the first fluid supplied to the first heat load processing unit can be brought close to the temperature corresponding to the first load. become.

  A heat pump system according to a fourth aspect is the heat pump system according to the second aspect, wherein the control unit is a target value of the temperature of the first fluid flowing through a portion of the first branch path that has passed through the first heat exchanger in the flow rate adjustment control. And the target value of the temperature of the 1st fluid which flows through the part which passed the 2nd heat exchanger among the 2nd branch paths is controlled so that it may become temperature corresponding to the 1st heat load.

  In this heat pump system, not only the temperature of the first fluid flowing through the portion of the first branch passage that has passed through the first heat exchanger but also the first fluid that flows through the portion of the second branch passage that has passed through the second heat exchanger. Are controlled so as to approach the temperature corresponding to the first heat load required in the first heat load processing unit. As a result, it is possible to avoid a state where the temperature of the first fluid flowing through the first heat load circuit greatly exceeds the temperature corresponding to the first heat load, and heat dissipation loss can be effectively reduced.

  In addition, when the first flow rate adjustment mechanism is controlled aiming at the temperature corresponding to the first heat load, the first heat load circuit is provided with a function of adjusting the temperature of the first fluid heading to the first heat load processing unit. It becomes possible to eliminate the necessity.

  The heat pump system according to a fifth aspect of the present invention is the heat pump system according to any one of the second to fourth aspects of the present invention, wherein the control unit controls the compression ratio in the low-stage compression mechanism and the compression ratio in the high-stage compression mechanism in the flow rate adjustment control. In order to maintain a state that satisfies a predetermined compression ratio condition including the case where the ratio of 1 is 1, or the difference between the compression ratio in the low-stage side compression mechanism and the compression ratio in the high-stage side compression mechanism At least one of the low-stage compression mechanism, the high-stage compression mechanism, and the expansion mechanism is controlled so as to reduce the size.

  In this heat pump system, the temperature of the primary refrigerant flowing into the second heat exchanger is adjusted so that the temperature of the primary refrigerant flowing into the first heat exchanger is equal to or higher than the temperature of the first fluid flowing into the first heat exchanger. Both the temperature of the primary refrigerant flowing into the first heat exchanger and the temperature of the primary refrigerant flowing into the second heat exchanger while corresponding to the temperature of the first fluid flowing into the second heat exchanger correspond to the first heat load. When the flow rate adjustment control is performed so that the temperature is equal to or higher than the temperature, the compressor driving force required in the high-stage compression mechanism and the low-stage compression mechanism can be reduced. As a result, not only the heat dissipation loss due to the first fluid can be reduced, but also the heat load in the first heat load processing section can be realized simultaneously with a small driving force, and the efficiency can be further improved.

  The heat pump system according to a sixth aspect of the present invention is the heat pump system according to the fifth aspect of the present invention, wherein when the flow rate adjustment control is performed, the control unit causes the low-stage compression mechanism to operate when the discharge temperature of the primary refrigerant of the low-stage compression mechanism increases. Low-stage suction superheat control is performed to increase the superheat of the primary refrigerant to be sucked.

  Generally, when the target value of the primary refrigerant discharge temperature of the low-stage compression mechanism is high, the compression ratio of the low-stage compression mechanism tends to increase. This also increases the compression ratio of the high-stage compression mechanism. For this reason, the required driving force of the compression mechanism increases and the energy consumption increases.

  In contrast, in this heat pump system, when the target value of the primary refrigerant discharge temperature of the low-stage compression mechanism is increased, the target value of the superheat degree of the primary refrigerant sucked by the low-stage compression mechanism is increased. Perform stage suction superheat control. For this reason, the compression ratio of the low-stage compression mechanism that is necessary for the discharge temperature of the primary refrigerant of the low-stage compression mechanism to reach the target value can be kept small. Accompanying this, the compression ratio of the high-stage compression mechanism can also be kept small. As a result, the required driving force of the compression mechanism can be further reduced. On the other hand, when the target value of the primary refrigerant discharge temperature of the low-stage compression mechanism becomes low, the compression ratio of the low-stage compression mechanism is reduced by reducing the degree of superheat of the primary refrigerant sucked by the low-stage compression mechanism. By suppressing this increase, it is possible to reduce the specific volume of the primary refrigerant sucked by the low-stage compression mechanism while suppressing an increase in the compression ratio of the high-stage compression mechanism. Thereby, it is possible to increase the capacity by securing the circulation amount while suppressing the increase in the compression ratio.

  A heat pump system according to a seventh aspect is the heat pump system according to the sixth aspect, wherein the heat pump circuit flows toward the expansion mechanism after passing through the primary refrigerant sucked by the low-stage compression mechanism and the second heat exchanger. It further has a primary inter-refrigerant heat exchanger that exchanges heat with the primary refrigerant. The control unit performs low-stage suction superheat degree control using the primary refrigerant heat exchanger.

  In this heat pump system, heat for cooling the primary refrigerant before flowing into the expansion mechanism can be recovered as heat for increasing the degree of superheat of the primary refrigerant sucked by the low-stage compression mechanism. As a result, not only can the degree of superheat of the primary refrigerant sucked by the low-stage compression mechanism be increased, but also a reduction in the amount of primary refrigerant passing through the expansion mechanism can be suppressed, and the capability can be improved. .

  A heat pump system according to an eighth aspect of the present invention is the heat pump system according to any one of the fifth to seventh aspects of the present invention, wherein the control unit performs the flow rate adjustment control from the first heat load processing unit to the first heat exchanger and the second heat exchange system. When the temperature of the first fluid flowing toward the heat exchanger rises, overheating of the primary refrigerant sucked by the low-stage compression mechanism while lowering the target value of the primary refrigerant discharge temperature of the low-stage compression mechanism Control when reducing the load to reduce the degree.

  In this heat pump system, when the temperature of the first fluid flowing from the first heat load circuit toward the first heat exchanger and the second heat exchanger rises, the heat load in the first heat load processing unit is reduced. Therefore, even when the operation state is changed to the above-described efficient operation state, the load can be handled. In addition, the density of the primary refrigerant sucked by the low-stage compression mechanism can be increased, and the circulation amount of the primary refrigerant can be increased. This makes it possible to increase the capacity of the heat pump circuit while accommodating load fluctuations.

  A heat pump system according to a ninth aspect of the present invention is the heat pump system according to the eighth aspect of the present invention, which has a second heat load portion, a second heat load circuit through which the second fluid circulates, and a second heat circuit through which the second heat load circuit circulates. And a third heat exchanger that exchanges heat between the fluid and the primary refrigerant that is on the way from the high-stage compression mechanism toward the second heat exchanger.

  In this heat pump system, the heat of the primary refrigerant discharged from the high-stage compression mechanism can only be used for both the heat load process in the first heat load circuit and the heat load process in the second heat load circuit. Instead, it is possible to use the second heat load circuit outside the temperature range required for the first heat load circuit.

  A heat pump system according to a tenth aspect of the invention is the heat pump system according to the ninth aspect of the invention, wherein the second fluid passing from the second heat load processing section to the third heat exchanger out of the second fluid passing through the second heat load circuit, It further includes a fourth heat exchanger that exchanges heat with the primary refrigerant that has passed through the heat exchanger and is still on its way to the expansion mechanism.

  In this heat pump system, when the temperature change range of the first fluid in the first heat load processing unit is included in the temperature change range of the second fluid in the second heat load processing unit, the high-stage compression mechanism is Of the primary refrigerant to be discharged, heat exchange with the primary refrigerant at a high temperature and heat exchange with the primary refrigerant at a low temperature are assigned to heat exchange with the second fluid, and the primary refrigerant at the intermediate temperature is heat with the first fluid. Can be used for exchange. Thereby, heat exchange in the second heat exchanger, the third heat exchanger, and the fourth heat exchanger can be performed while the temperature difference between the first fluid and the second fluid and the primary refrigerant is kept small. Therefore, the heat exchange efficiency can be improved.

  A heat pump system according to an eleventh aspect of the invention is the heat pump system according to the ninth or tenth aspect of the invention, wherein the control unit is configured such that the target value of the temperature of the primary refrigerant discharged from the low-stage compression mechanism is the primary refrigerant discharged from the high-stage compression mechanism. The second heat load circuit is set so that the temperature of the primary refrigerant passing through the third heat exchanger approaches the target value of the temperature of the primary refrigerant discharged by the low-stage compression mechanism when the temperature is lower than the target value of the temperature. The circulation amount of the circulating second fluid is adjusted.

  In this heat pump system, the maximum temperature of the primary refrigerant flowing through the first heat exchanger and the maximum temperature of the primary refrigerant flowing through the second heat exchanger are brought close to each other, so that the first heat exchanger in the first branch passage is passed. It becomes easy to make the temperature of the 1st fluid which flows through the part and the temperature of the 1st fluid which flows through the part which passed the 2nd heat exchanger out of the 2nd branch way close.

  For example, when it is desired to keep the flow rate of the first fluid supplied to the first heat load processing unit low, the time for the first fluid to pass through the first heat exchanger or the time for the second fluid to pass through the second heat exchanger. Even if it becomes longer, the temperature of the primary refrigerant flowing through the first heat exchanger approaches the temperature of the primary refrigerant flowing through the second heat exchanger. Therefore, either the temperature of the first fluid that flows through the portion of the first branch passage that has passed through the first heat exchanger or the temperature of the first fluid that flows through the portion of the second branch passage that has passed through the second heat exchanger. With respect to the above, it becomes possible to converge to a value in the vicinity of the temperature of the primary refrigerant flowing through the first heat exchanger (the temperature of the primary refrigerant flowing through the second heat exchanger).

  A heat pump system according to a twelfth aspect of the present invention is the heat pump system according to any one of the ninth to eleventh aspects of the present invention, wherein the second heat load processing unit is a hot water supply tank. The second fluid is water for hot water supply.

  In this heat pump system, hot water can be produced using the temperature of the primary refrigerant discharged from the high-stage compression mechanism.

  The heat pump system according to a thirteenth aspect of the present invention is the heat pump system according to any one of the second to twelfth aspects of the present invention, wherein the control unit operates the first flow rate adjustment mechanism in the flow rate adjustment control, thereby operating the first of the first branch paths. Of the temperature of the first fluid flowing through the portion that has passed through the first heat exchanger and the temperature of the first fluid flowing through the portion of the second branch passage that has passed through the second heat exchanger, the flow rate of the lower temperature is decreased. .

  In this heat pump system, the temperature of the first fluid flowing through the portion of the first branch passage that has passed through the first heat exchanger, and the first fluid flowing through the portion of the second branch passage that has passed through the second heat exchanger. By lowering the flow rate of the lower one of the temperatures, the flow rate of the lower temperature is lowered and the heating time can be lengthened. This makes it possible to increase the amount of heat recovered from the primary refrigerant on the side of the first heat exchanger and the second heat exchanger where the flow rate has been reduced.

  For example, when the first heat exchanger or the second heat exchanger is passed at a high flow rate without being heated to the inlet temperature of the primary refrigerant, the passage speed is decreased and the heat exchange time is increased. By doing so, the amount of heat recovery can be increased.

  A heat pump system according to a fourteenth aspect is the heat pump system according to the thirteenth aspect, wherein the first flow rate adjusting mechanism is configured to obtain a ratio between a flow rate of the first fluid flowing through the first branch path and a flow rate of the first fluid flowing through the second branch path. It is adjustable. In the flow rate adjustment control, the control unit operates the first flow rate adjustment mechanism to keep the flow rate of the first fluid supplied to the first thermal load processing unit constant, and the first heat exchange in the first branch path. Of the temperature of the first fluid flowing through the portion that has passed through the vessel and the temperature of the first fluid flowing through the portion of the second branch passage that has passed through the second heat exchanger, the flow rate ratio of the lower temperature is lowered.

  In this heat pump system, by adjusting the flow rate ratio, the temperature of the first fluid flowing through the portion of the first branch passage that has passed through the first heat exchanger and the second branch passage of the second branch passage are passed. Of the temperature of the first fluid flowing through the part, the higher flow rate increases and the heating time becomes shorter, and the lower flow rate decreases and the heating time becomes longer. Thereby, the temperature of the 1st fluid which flows through the part which passed the 1st heat exchanger among the 1st branch paths, and the temperature of the 1st fluid which flows through the part which passed the 2nd heat exchanger among the 2nd branch paths Both can be changed to reduce the temperature difference. Further, when there is no change in the heat load in the first heat load processing unit, not only can the temperature difference be reduced, but also the first heat load can be maintained by maintaining the flow rate of the first fluid supplied to the first heat load processing unit. It becomes possible to cope with the heat load in the processing section.

  A heat pump system according to a fifteenth aspect is the heat pump system according to the thirteenth aspect, wherein the first flow rate adjustment mechanism is capable of adjusting the flow rate of the first fluid supplied to the first thermal load processing unit. The control unit includes a temperature of the first fluid flowing through a portion of the first branch passage that has passed the first heat exchanger, and a temperature of the first fluid flowing through a portion of the second branch passage that has passed the second heat exchanger. When the flow rate ratio of the lower temperature is small, in the flow rate adjustment control, the flow rate of the first fluid supplied to the first thermal load processing unit is lowered by operating the first flow rate adjustment mechanism.

  In this heat pump system, the temperature of the first fluid that flows through the portion of the first branch passage that has passed through the first heat exchanger and the temperature of the first fluid that flows through the portion of the second branch passage that has passed through the second heat exchanger. If the flow rate of the first fluid supplied to the first thermal load processing unit is lowered when the flow rate ratio of the lower temperature is smaller, the temperature of the lower temperature is higher than the temperature increase of the higher temperature. The rise will be larger. Thereby, it becomes possible to change so as to reduce the temperature difference. Moreover, when the heat load in the first heat load processing unit is reduced, not only can the temperature difference be reduced, but also the heat load in the first heat load processing unit can be handled.

  A heat pump system according to a sixteenth aspect of the present invention is the heat pump system according to the thirteenth aspect, wherein the first flow rate adjusting mechanism calculates a ratio between a flow rate of the first fluid flowing through the first branch path and a flow rate of the first fluid flowing through the second branch path. A ratio adjusting unit for adjusting and a flow rate adjusting unit for adjusting the flow rate of the first fluid supplied to the first thermal load processing unit are included. In the flow rate adjustment control, the control unit operates the first flow rate adjustment mechanism to change the temperature of the first fluid flowing through the portion of the first branch passage that has passed through the first heat exchanger and the second branch passage of the second branch passage. One of the temperature of the first fluid flowing through the portion that has passed through the two heat exchangers and the flow rate that exceeds the temperature corresponding to the first heat load is increased and / or the temperature that does not satisfy the temperature corresponding to the first heat load And the controller supplies the first heat load to the first heat load processor when the temperature of the first fluid supplied to the first heat load processor exceeds the temperature corresponding to the first heat load. As the temperature of the fluid rises, the flow rate of the first fluid supplied to the first thermal load processing unit is lowered.

  In this heat pump system, the temperature of the first fluid that flows through the portion of the first branch passage that has passed through the first heat exchanger and the temperature of the first fluid that flows through the portion of the second branch passage that has passed through the second heat exchanger. The flow rate of the first fluid flowing through the first thermal load circuit can be made to be an amount corresponding to the thermal load in the first thermal load processing unit.

  A heat pump system according to a seventeenth aspect of the present invention is the heat pump system according to any one of the first to sixteenth aspects of the present invention, wherein the first fluid grasps the temperature of the first fluid flowing through the portion of the first branch passage that has passed through the first heat exchanger. It further comprises a branch temperature detecting means and a second branch temperature detecting means for grasping the temperature of the first fluid flowing through the portion of the second branch that has passed through the second heat exchanger.

  In this heat pump system, the temperature of the first fluid that flows through the portion of the first branch passage that has passed through the first heat exchanger and the temperature of the first fluid that flows through the portion of the second branch passage that has passed through the second heat exchanger. Therefore, it is possible to improve the accuracy of the flow rate adjustment control.

  A heat pump system according to an eighteenth aspect of the present invention is the heat pump system according to any one of the first to sixteenth aspects, further comprising a branching portion temperature detecting means and a merging portion temperature detecting means. The branching portion temperature detecting means includes the temperature of the first fluid flowing through the portion of the first branch passage that has passed through the first heat exchanger and the first fluid flowing through the portion of the second branch passage that has passed through the second heat exchanger. Know at least one of the temperatures. The merged part temperature detecting means grasps the temperature of the first fluid that flows toward the first thermal load processing unit after the first fluid that has passed through the first branch path and the first fluid that has passed through the second branch path have merged. To do.

  In this heat pump system, the temperature of the first fluid that flows through the portion of the first branch passage that has passed through the first heat exchanger and the temperature of the first fluid that flows through the portion of the second branch passage that has passed through the second heat exchanger. Any of the above can be directly grasped by the branching part temperature detecting means, and the temperature of the first fluid after joining can be directly grasped by the joining part temperature detecting means. Thereby, it is possible to improve the accuracy of the flow rate adjustment control by controlling so that the difference between the temperature grasped by the branching portion temperature detecting means and the temperature grasped by the joining portion temperature detecting means becomes small.

  The heat pump system according to a nineteenth aspect of the present invention is the heat pump system according to any one of the first to sixteenth aspects of the present invention, a first branch flow rate detecting means for grasping a flow rate of the first fluid flowing through the first branch, and a second branch And a second branch flow rate detecting means for grasping the flow rate of the first fluid flowing through the first fluid.

  In this heat pump system, it is possible to directly grasp the flow rate of the first fluid flowing through the first branch path and the flow rate of the first fluid flowing through the second branch path, so that it is possible to improve the accuracy of the flow rate control. .

  A heat pump system according to a twentieth aspect of the present invention is the heat pump system according to any one of the first to sixteenth aspects of the invention, wherein at least one of a flow rate of the first fluid flowing through the first branch path and a flow rate of the first fluid flowing through the second branch path. The flow rate of the first fluid that flows toward the first thermal load processing unit after the branching part flow rate detecting means for grasping one of the first fluid flowing through the first branching channel and the first fluid flowing through the second branching channel join together. And a merging partial flow rate detecting means for grasping.

  In this heat pump system, either the flow rate of the first fluid flowing through the first branch passage or the flow rate of the first fluid flowing through the second branch passage is determined by the branching portion flow rate detecting means, and the flow rate of the first fluid after joining is joined. It is possible to directly grasp the flow rate detection means. As a result, the flow rate on the side of the first branch path and the second branch path on which the branch partial flow rate detection unit is not provided is determined by the flow rate determined by the branch partial flow rate detection unit and the flow rate determined by the merged partial flow rate detection unit. It can be grasped as a difference. Thereby, it is possible to improve the accuracy of the flow rate adjustment control.

  The heat pump system according to a twenty-first aspect of the present invention is the heat pump system according to any one of the first to twentieth aspects of the invention, wherein, in the first heat exchanger, the discharge side of the low-stage compression mechanism is directed toward the suction side of the high-stage compression mechanism. The flowing primary refrigerant and the first fluid flowing through the first branch path are in a counterflow relationship. In the second heat exchanger, the primary refrigerant that flows from the high-stage compression mechanism toward the expansion mechanism and the first fluid that flows through the second branch passage are in a counterflow relationship.

  In this heat pump system, the temperature required for the temperature of the primary refrigerant discharged from the low-stage compression mechanism and the temperature of the primary refrigerant discharged from the high-stage compression mechanism can be kept low. As a result, the driving force of the compression mechanism can be kept small.

  A heat pump system according to a 22nd aspect of the present invention is the heat pump system according to any one of the first to 21st aspects of the present invention, wherein the first heat load processing unit is a heating heat exchanger that heats the air in the target space. The first fluid is a secondary refrigerant.

  In this heat pump system, it is possible to warm the space in which the first thermal load processing unit is arranged.

  A heat pump system according to a twenty-third aspect of the present invention is the heat pump system according to any one of the first to twenty-second aspects, wherein the low-stage compression mechanism and the high-stage compression mechanism are respectively common for performing compression work by being rotationally driven. It has a rotation axis.

  In this heat pump system, it is possible to increase the driving efficiency by providing a phase difference of 180 degrees while sharing the rotating shaft.

  A heat pump system according to a twenty-fourth aspect is the heat pump system according to any one of the first to twenty-third aspects, wherein the control unit sets the discharge pressure of the high-stage compression mechanism to a pressure equal to or higher than the critical pressure of the primary refrigerant in the flow rate adjustment control. Is maintained. It is used in an environment where the ambient temperature of the first heat load processing unit is a temperature lower than the critical temperature of the primary refrigerant.

  In this heat pump system, the primary refrigerant in a state exceeding the critical pressure is supplied to the heat load at a temperature lower than the critical temperature of the primary refrigerant, so that the gradient of the primary refrigerant isotherm on the Mollier diagram is gentle. Heat dissipation treatment can be performed in the area. For this reason, it becomes possible to perform an operation in which the difference in enthalpy between the start and end of the heat release process of the primary refrigerant is increased.

  A heat pump system according to a twenty-fifth aspect of the present invention is the heat pump system according to any one of the first to twenty-fourth aspects, wherein the primary refrigerant is carbon dioxide.

  In this heat pump system, a refrigeration cycle of a heat pump circuit can be realized using natural refrigerant.

  As described above, according to the present invention, the following effects can be obtained.

  In the first invention, it is possible to improve the processing efficiency of the heat load in the first load heat exchanger by the heat pump system.

  In the second invention, it becomes possible to cope with the heat load in the first load heat exchanger only by the amount of heat obtained by the first fluid in the first heat exchanger and the second heat exchanger.

  In 3rd invention, in order to raise the efficiency of a heat pump circuit, it passes through the 2nd heat exchanger among the temperature of the 1st fluid which flows through the part which passed the 1st heat exchanger among the 1st branch, and the 2nd branch. Even if the temperature of the first fluid flowing through the part exceeds the temperature corresponding to the first heat load, the temperature of the first fluid supplied to the first heat load processing unit is brought close to the temperature corresponding to the first load. Is possible.

  In the fourth aspect of the invention, it is possible to avoid a state in which the temperature of the first fluid flowing through the first heat load circuit greatly exceeds the temperature corresponding to the first heat load, and it is possible to effectively reduce heat dissipation loss. .

  In the fifth aspect of the invention, not only the heat dissipation loss due to the first fluid can be reduced, but also the heat load in the first heat load processing section can be simultaneously realized with a small driving force, and the efficiency can be further improved. Become.

  In the sixth aspect of the invention, it is possible to increase the capacity by securing the circulation amount while suppressing the increase in the compression ratio.

  In the seventh aspect of the invention, not only can the degree of superheat of the primary refrigerant sucked by the low-stage compression mechanism be increased, but also a reduction in the amount of passage of the primary refrigerant in the expansion mechanism can be suppressed, and the ability can be improved. become.

  In the eighth invention, it is possible to increase the capacity of the heat pump circuit while dealing with load fluctuations.

  In the ninth invention, the heat of the primary refrigerant discharged from the high-stage compression mechanism can only be used for both the heat load process in the first heat load circuit and the heat load process in the second heat load circuit. Instead, it is possible to use the second heat load circuit outside the temperature range required for the first heat load circuit.

  In the tenth invention, heat exchange is performed in the second heat exchanger, the third heat exchanger, and the fourth heat exchanger while the temperature difference between the first fluid and the second fluid and the primary refrigerant is kept small. Therefore, the heat exchange efficiency can be improved.

  In the eleventh aspect of the invention, the temperature of the first fluid that flows through the portion of the first branch path that has passed through the first heat exchanger and the temperature of the first fluid that flows through the portion of the second branch path that has passed through the second heat exchanger. It becomes easy to approach.

  In the twelfth aspect, hot water can be produced using the temperature of the primary refrigerant discharged from the high-stage compression mechanism.

  In the thirteenth aspect, it is possible to increase the amount of heat recovered from the primary refrigerant on the side of the first heat exchanger and the second heat exchanger where the flow rate is reduced.

  In the fourteenth invention, the temperature of the first fluid flowing through the portion of the first branch passage that has passed through the first heat exchanger and the temperature of the first fluid flowing through the portion of the second branch passage that has passed through the second heat exchanger. Both can be changed so as to reduce the temperature difference, and if there is no change in the thermal load in the first thermal load processing unit, not only the temperature difference can be reduced but also the first thermal load processing unit. By maintaining the flow rate of the first fluid supplied to, it becomes possible to cope with the thermal load in the first thermal load processing section.

  In the fifteenth aspect, it is possible to change so as to reduce the temperature difference. Moreover, when the heat load in the first heat load processing unit is reduced, not only can the temperature difference be reduced, but also the heat load in the first heat load processing unit can be handled.

  In the sixteenth aspect of the invention, the temperature of the first fluid that flows through the portion of the first branch passage that has passed through the first heat exchanger and the temperature of the first fluid that flows through the portion of the second branch passage that has passed through the second heat exchanger. The flow rate of the first fluid flowing through the first thermal load circuit can be made to be an amount corresponding to the thermal load in the first thermal load processing unit.

  In the seventeenth aspect, it is possible to improve the accuracy of the flow rate adjustment control.

  In the eighteenth aspect of the invention, it is possible to improve the accuracy of the flow rate adjustment control by controlling the difference between the temperature grasped by the branching portion temperature detecting means and the temperature grasped by the joining portion temperature detecting means. .

  In the nineteenth aspect, it is possible to improve the accuracy of the flow rate adjustment control.

  In the twentieth invention, it is possible to improve the accuracy of the flow rate adjustment control.

  In the twenty-first aspect, the driving force of the compression mechanism can be kept small.

  In the twenty-second aspect, it is possible to warm the space in which the first thermal load processing unit is arranged.

  In the twenty-third aspect, it is possible to increase the driving efficiency by providing a phase difference of 180 degrees while sharing the rotation axis.

  In the twenty-fourth aspect of the invention, it is possible to perform an operation with an increased enthalpy difference between the start and end of the primary refrigerant heat release process.

  In the twenty-fifth aspect, a refrigeration cycle of a heat pump circuit can be realized using a natural refrigerant.

1 is a schematic configuration diagram of a heat pump system according to a first embodiment of the present invention. It is a pressure-enthalpy diagram of the heat pump circuit concerning a 1st embodiment. It is a temperature-entropy diagram of the heat pump circuit concerning 1st Embodiment. It is a schematic block diagram of the heat pump system concerning 2nd Embodiment. It is a schematic block diagram of the heat pump system concerning 3rd Embodiment. It is a schematic block diagram of the heat pump system concerning 4th Embodiment. It is a schematic block diagram of the heat pump system concerning 5th Embodiment. It is a schematic block diagram of the heat pump system concerning the modification A of 5th Embodiment. It is a schematic block diagram of the heat pump system concerning the modification B of 5th Embodiment. It is a schematic block diagram of the heat pump system concerning the modification C of 5th Embodiment. It is a schematic block diagram of the heat pump system concerning 6th Embodiment. It is a schematic block diagram of the heat pump system concerning the modification A of 6th Embodiment. It is a schematic block diagram of the heat pump system concerning 7th Embodiment. It is a schematic block diagram of the heat pump system concerning 8th Embodiment. It is a schematic block diagram of the heat pump system concerning 9th Embodiment. It is a schematic block diagram of the heat pump system concerning 10th Embodiment. It is a schematic block diagram of the heat pump system concerning 11th Embodiment. It is a schematic block diagram of the heat pump system concerning 12th Embodiment. It is a schematic block diagram of the heat pump system concerning 13th Embodiment. It is a schematic block diagram of the heat pump system concerning the modification <14-5> of each embodiment. It is a schematic block diagram of the heat pump system concerning the modification <14-5> of each embodiment. It is a figure which shows the Mollier diagram of the modification <14-8> of each embodiment. It is a figure which shows the Mollier diagram of the modification <14-9> of each embodiment. It is a schematic block diagram of the heat pump system concerning the modification <14-11> of each embodiment. It is a schematic block diagram of the heat pump system concerning the modification <14-12> of each embodiment. It is a schematic block diagram of the heat pump system concerning the modification <14-13> of each embodiment. It is a figure which shows the comparative example about the Mollier diagram of the modification <14-17> of each embodiment. It is a figure which shows the Mollier diagram of the modification <14-17> of each embodiment. It is a figure which shows the Mollier diagram of the modification <14-18> of each embodiment.

<1> First Embodiment <1-1> Configuration of Heat Pump System 1 FIG. 1 is a schematic configuration diagram of a heat pump system 1 according to a first embodiment which is an embodiment of the present invention.

  The heat pump system 1 includes a heat pump circuit 10, a heating circuit 60, a hot water supply circuit 90, an intermediate pressure water heat exchanger 40, and a high pressure water heat exchanger 50. The heat pump system 1 is a system that not only uses the heat obtained by the heat pump circuit 10 as heating heat via the heating circuit 60 but also uses it as hot water supply heat via the hot water supply circuit 90.

(Intermediate pressure water heat exchanger 40)
In the intermediate pressure water heat exchanger 40, heat exchange is performed between carbon dioxide as a primary refrigerant circulating in the heat pump circuit 10 and water as a secondary refrigerant circulating in the heating circuit 60.

(High pressure water heat exchanger 50)
The high-pressure water heat exchanger 50 includes a first high-pressure water heat exchanger 51, a second high-pressure water heat exchanger 52, and a third high-pressure water heat exchanger 53. In the first high-pressure water heat exchanger 51, heat exchange is performed between carbon dioxide as a primary refrigerant circulating in the heat pump circuit 10 and hot water supply water circulating in the hot water supply circuit 90. In the second high-pressure water heat exchanger 52, heat exchange is performed between carbon dioxide as a primary refrigerant circulating in the heat pump circuit 10 and water as a secondary refrigerant circulating in the heating circuit 60. In the third high-pressure water heat exchanger 53, heat exchange is performed between carbon dioxide as a primary refrigerant circulating in the heat pump circuit 10 and hot water supply water circulating in the hot water supply circuit 90.

(Heat pump circuit 10)
The heat pump circuit 10 is a circuit using a natural refrigerant in which carbon dioxide as a primary refrigerant is circulated. The heat pump circuit 10 includes a low-stage compressor 21, a high-stage compressor 25, an economizer heat exchanger 7, an injection path 70, a primary inter-refrigerant heat exchanger 8, a primary bypass 80, an expansion valve 5a, an evaporator 4, an intermediate The pressure tube 23, the high pressure tube 27, the low pressure tube 20, the fan 4 f, and the control unit 11 are provided. The evaporator 4 is installed outdoors, for example.

  The intermediate pressure pipe 23 connects the discharge side of the low-stage compressor 21 and the suction side of the high-stage compressor 25. The intermediate pressure tube 23 includes a first intermediate pressure tube 23a, a second intermediate pressure tube 23b, a third intermediate pressure tube 23c, and a fourth intermediate pressure tube 23d.

  The first intermediate pressure pipe 23 a connects the discharge side of the low-stage compressor 21 and the upstream end of the intermediate-pressure water heat exchanger 40 through the low-stage discharge point B. An intermediate pressure temperature sensor 23T that detects the temperature of the passing primary refrigerant is attached to the first intermediate pressure pipe 23a. The second intermediate pressure pipe 23b passes through the intermediate pressure water heat exchanger 40 while flowing carbon dioxide as the primary refrigerant therein so as not to mix with the heating water as the secondary refrigerant. . The third intermediate pressure pipe 23c connects the downstream side end portion of the intermediate pressure water heat exchanger 40 and the injection confluence point D via the intermediate pressure water heat exchanger passage point C. The fourth intermediate pressure pipe 23d connects the injection merging point D and the suction side of the high-stage compressor 25. A high stage suction pressure sensor 24P for detecting the pressure of the passing primary refrigerant and a high stage suction temperature sensor 24T for detecting the temperature of the passing primary refrigerant are attached to the fourth intermediate pressure pipe 23d.

  The high-pressure pipe 27 connects the discharge side of the high-stage compressor 25 and the expansion valve 5 or the primary bypass expansion valve 5b. The high pressure pipe 27 includes a first high pressure pipe 27a, a second high pressure pipe 27b, a third high pressure pipe 27c, a fourth high pressure pipe 27d, a fifth high pressure pipe 27e, a sixth high pressure pipe 27f, a seventh high pressure pipe 27g, and an eighth high pressure pipe. A tube 27h, a ninth high-pressure tube 27i, a tenth high-pressure tube 27j, an eleventh high-pressure tube 27k, a twelfth high-pressure tube 271 and a thirteenth high-pressure tube 27m are provided.

  The first high-pressure pipe 27a connects the discharge side of the high-stage compressor 25 and the first high-pressure water heat exchanger 51 via the high-stage discharge point E. A high pressure sensor 27P for detecting the pressure of the passing primary refrigerant and a high pressure temperature sensor 27T for detecting the temperature of the passing primary refrigerant are attached to the first high pressure pipe 27a. The second high-pressure pipe 27 b passes through the first high-pressure water heat exchanger 51 while flowing carbon dioxide as a primary refrigerant therein so as not to mix with hot water. The third high-pressure pipe 27c connects the downstream end of the first high-pressure water heat exchanger 51 and the upstream end of the second high-pressure water heat exchanger 52 via the first high-pressure point F. Yes. The fourth high-pressure pipe 27d passes through the second high-pressure water heat exchanger 52 while flowing carbon dioxide as the primary refrigerant therein so that it does not mix with water as the secondary refrigerant for heating. . The fifth high-pressure pipe 27e connects the downstream end of the second high-pressure water heat exchanger 52 and the upstream end of the third high-pressure water heat exchanger 53 via the second high-pressure point G. Yes. The sixth high-pressure pipe 27f passes through the third high-pressure water heat exchanger 53 while flowing carbon dioxide as the primary refrigerant therein so as not to mix with water as the secondary refrigerant for heating. . The seventh high-pressure pipe 27g connects the downstream end of the third high-pressure water heat exchanger 53 and the third high-pressure point H. The eighth high-pressure pipe 27h connects the third high-pressure point H and the upstream end in the flow direction of the primary refrigerant toward the expansion valve 5a side in the economizer heat exchanger 7. The ninth high-pressure pipe 27i passes through the economizer heat exchanger 7 while flowing the primary refrigerant therein so as not to mix with the primary refrigerant flowing through the injection passage 70. The tenth high pressure pipe 27j connects the downstream side end portion in the flow direction of the primary refrigerant toward the expansion valve 5a side in the economizer heat exchanger 7 and the fourth high pressure point I. The eleventh high-pressure pipe 27k connects the fourth high-pressure point I and the upstream end in the flow direction of the primary refrigerant toward the expansion valve 5a in the primary refrigerant heat exchanger 8. The twelfth high-pressure pipe 27l passes through the primary inter-refrigerant heat exchanger 8 while flowing the primary refrigerant therein so as not to mix with the primary refrigerant flowing through the low-pressure pipe 20. The thirteenth high pressure pipe 27m connects the downstream end in the flow direction of the primary refrigerant toward the expansion valve 5a side in the heat exchanger 8 between the primary refrigerants and the expansion valve 5a via the fifth high pressure point J. is doing.

  The low pressure pipe 20 includes a first low pressure pipe 20a, a second low pressure pipe 20b, a third low pressure pipe 20c, a fourth low pressure pipe 20d, and a fifth low pressure pipe 20e. The first low-pressure pipe 20a connects the expansion valve 5a and the third low-pressure point M via the first low-pressure point K. The second low-pressure pipe 20 b connects the third low-pressure point M and the upstream end of the evaporator 4. The third low-pressure pipe 20c is connected to the downstream end of the evaporator 4 and the upstream end in the flow direction of the primary refrigerant in the low-pressure pipe 20 of the primary refrigerant heat exchanger 8 via the fourth low-pressure point N. While connecting. The fourth low-pressure pipe 20d passes through the primary inter-refrigerant heat exchanger 8 while flowing the primary refrigerant therein so as not to mix with the primary refrigerant flowing through the twelfth high-pressure pipe 271l. The fifth low-pressure pipe 20 e connects the downstream end in the flow direction of the primary refrigerant in the low-pressure pipe 20 of the primary refrigerant heat exchanger 8 and the suction point A that is the suction side of the low-stage compressor 21. is doing. The fifth low-pressure pipe 20e is provided with a low-pressure sensor 20P that detects the pressure of the passing primary refrigerant and a low-pressure temperature sensor 20T that detects the temperature of the passing primary refrigerant.

  The injection path 70 includes an injection expansion valve 73, a first injection pipe 72, a second injection pipe 74, a third injection pipe 75, and a fourth injection pipe 76.

  The first injection pipe 72 connects the third high pressure point H and the injection expansion valve 73. The second injection pipe 74 connects the injection expansion valve 73 and the upstream end in the flow direction of the primary refrigerant flowing through the injection path 70 in the economizer heat exchanger 7 via the injection intermediate pressure point Q. Yes. The third injection pipe 75 passes through the economizer heat exchanger 7 while flowing the primary refrigerant therein so as not to mix with the primary refrigerant flowing through the ninth high-pressure pipe 27i. The fourth injection pipe 76 connects the downstream end in the flow direction of the primary refrigerant flowing through the injection path 70 in the economizer heat exchanger 7 and the injection confluence point D via the post-economizer heat exchange point R. ing.

  Thus, in the heat pump circuit 10, since the injection path 70 is adopted, the coefficient of performance of the heat pump circuit can be improved. And even when the cooling effect of the primary refrigerant in the intermediate pressure water heat exchanger 40 for improving the efficiency of the heat pump circuit 10 cannot be sufficiently obtained, for example, when the heating load is small, the injection path 70 Driving efficiency can be improved by increasing the amount of injection that passes through. In the heat pump circuit 10, the injection confluence point D is provided between the intermediate pressure water heat exchanger 40 and the high stage compressor 25. Therefore, the high-temperature primary refrigerant discharged from the low-stage compressor 21 is not cooled before reaching the intermediate-pressure water heat exchanger 40, and the intermediate-pressure water heat exchanger is maintained while maintaining the high-temperature state. 40. For this reason, the water for heating which passes the intermediate pressure water heat exchanger 40 can be made high temperature enough. Further, the third high pressure point H is provided at a position where a part of the primary refrigerant can be branched to the injection path 70 on the upstream side of the economizer heat exchanger 7. For this reason, it is possible to avoid a decrease in capacity due to overcooling of the primary refrigerant from the low-stage compressor 21 toward the high-stage compressor 25.

  The primary bypass 80 includes a fourteenth high pressure pipe 27n, a sixth low pressure pipe 20f, and a primary bypass expansion valve 5b. The fourteenth high-pressure pipe 27n connects the fourth high-pressure point I and the primary bypass expansion valve 5b. The sixth low-pressure pipe 20f is connected via the primary bypass expansion valve 5b, the third low-pressure point M, and the second low-pressure point L. In addition, since the primary bypass expansion valve 5b is provided in the primary bypass 80, the control part 11 can adjust the quantity of the primary refrigerant | coolant which passes the heat exchanger 8 side between primary refrigerant | coolants. For this reason, it is possible to adjust the primary refrigerant sucked by the low-stage compressor 21 to have an appropriate degree of superheat. Specifically, when the valve opening degree of the primary bypass expansion valve 5b is lowered, the control unit 11 increases the flow rate of the primary refrigerant passing through the primary inter-refrigerant heat exchanger 8, and the low-stage compressor 21. Therefore, the degree of superheat of the primary refrigerant sucked in can be increased, and thereby the compression ratio required for the discharge refrigerant temperature of the low-stage compressor 21 to be the target temperature can be kept small. In addition, when the opening degree of the primary bypass expansion valve 5b is increased, the control unit 11 reduces the flow rate of the primary refrigerant passing through the primary inter-refrigerant heat exchanger 8, and the low-stage compressor 21 sucks it. The degree of superheat of the primary refrigerant can be reduced, and this can prevent a situation in which the suction refrigerant density of the low-stage compressor 21 is significantly reduced and the circulation amount cannot be secured.

  The control unit 11 includes the above-described intermediate pressure temperature sensor 23T, high stage suction pressure sensor 24P, high stage suction temperature sensor 24T, high pressure sensor 27P, high pressure sensor 27T, low pressure sensor 20P, and low pressure sensor 20T. Based on the detected value, the low-stage compressor 21, the high-stage compressor 25, the injection expansion valve 73, the expansion valve 5a, the primary bypass expansion valve 5b, the fan 4f, and the like are controlled.

(Heating circuit 60)
In the heating circuit 60, water as a secondary refrigerant circulates. The heating circuit 60 includes a radiator 61, a diversion mechanism 62, a heating forward pipe 65, a heating return pipe 66, an intermediate pressure side branch path 67, and a high pressure side branch path 68. The diversion mechanism 62 includes a heating mixing valve 64 and a heating pump 63. The radiator 61 is installed in a space to be heated, and warm water as a secondary refrigerant flows inside to heat the air in the target space. The radiator 61 is provided with a radiator temperature sensor 61T for detecting the temperature of the water for heating flowing inside. Although not shown, the radiator 61 has an outlet for receiving warm water sent from the heating pump 63, and the intermediate-pressure water heat exchanger 40 and the second high-pressure water heat exchanger 40 that radiate heat after being radiated by the radiator 61. And a return port for sending out to 52. The heating return pipe 66 connects the return port of the radiator 61 and the heating branch point X. At the heating branch point X, the intermediate pressure side branch path 67 that sends the water that has radiated heat from the radiator 61 to the intermediate pressure water heat exchanger 40 side, and the high pressure side branch path 68 that sends the water to the second high pressure water heat exchanger 52 side , Shunt. The heating return pipe 66 is provided with a heating return temperature sensor 66T that detects the temperature of the passing secondary refrigerant for heating.

  The intermediate pressure side branch path 67 includes a first intermediate pressure side branch path 67a, a second intermediate pressure side branch path 67b, and a third intermediate pressure side branch path 67c. The first intermediate pressure side branch path 67 a connects the branch point X and the upstream end portion in the water flow direction in the intermediate pressure side branch path 67 of the intermediate pressure water heat exchanger 40. The second intermediate pressure side branching passage 67b flows while heating water as a secondary refrigerant flows inside so as not to mix with carbon dioxide as a primary refrigerant flowing in the second intermediate pressure pipe 23b. It passes through the pressure water heat exchanger 40. Here, in the intermediate pressure water heat exchanger 40, carbon dioxide as the primary refrigerant flowing in the second intermediate pressure pipe 23b and heating for the secondary refrigerant flowing in the second intermediate pressure side branch passage 67b. As the water, a counter flow type that flows in directions opposite to each other is adopted. The third intermediate pressure side branch passage 67c connects the downstream end of the intermediate pressure side branch passage 67 of the intermediate pressure water heat exchanger 40 in the water flow direction and the heating junction point Y. The third intermediate pressure side branch path 67c is provided with an intermediate pressure side branch path temperature sensor 67T for detecting the temperature of the heating water passing therethrough.

  The high-pressure side branch path 68 includes a first high-pressure side branch path 68a, a second high-pressure side branch path 68b, and a third high-pressure side branch path 68c. The first high-pressure side branch 68a connects the branch point X and the upstream end in the water flow direction in the high-pressure side branch 68 of the second high-pressure water heat exchanger 52. The second high-pressure side branch 68b allows the heating water as the secondary refrigerant to flow in the inside so as not to mix with carbon dioxide as the primary refrigerant flowing in the fourth high-pressure pipe 27d. 2 It passes through the high-pressure water heat exchanger 52. Here, in the second high-pressure water heat exchanger 52, for heating as carbon dioxide as the primary refrigerant flowing in the fourth high-pressure pipe 27d and secondary refrigerant flowing in the second high-pressure side branch 68b. The counter flow type which is flowing in the direction opposite to each other is adopted. The third high-pressure side branch 68 c connects the downstream end of the second high-pressure water heat exchanger 52 in the high-pressure side branch 68 in the flow direction of water and the heating junction point Y. The third high pressure side branch 68c is provided with a high pressure side branch temperature sensor 68T for detecting the temperature of the heating water passing therethrough.

  The temperature of the water for heating flowing through the first intermediate pressure side branch passage 67a and the temperature of the water for heating flowing through the first high pressure side branch passage 68a are both branched at the heating branch point X. Since there is no heat exchange with the outside, the temperature distribution is the same. On the other hand, the temperature of the heating water flowing through the third intermediate pressure side branch passage 67c is equal to the amount of heat obtained by heat exchange with the primary refrigerant flowing through the second intermediate pressure pipe 23b in the intermediate pressure water heat exchanger 40. It becomes the corresponding temperature. Further, the temperature of the heating water flowing through the third high-pressure side branch 68 c is equal to the amount of heat obtained by heat exchange with the primary refrigerant flowing through the fourth high-pressure pipe 27 d in the second high-pressure water heat exchanger 52. It becomes the corresponding temperature. For this reason, the temperature of the water for heating which is flowing through the third intermediate pressure side branch passage 67c may be different from the temperature of the water for heating which is flowing through the third high pressure side branch passage 68c.

  The heating outlet pipe 65 connects the heating junction point Y and the outlet of the radiator 61. A heating pump 63 that adjusts the flow rate of heating water passing through the heating forward pipe 65 is provided in the middle of the heating forward pipe 65. The heating mixing valve 64 is provided at the heating sidestream point Y where the water for heating that has passed through the third intermediate pressure side branch 67c and the water for heating that has passed through the third high pressure side branch 68c merge. . The heating mixing valve 64 adjusts the opening degree of the part connected to the third intermediate pressure side branching path 67c side and the opening degree of the part connected to the third high pressure side branching path 68c side, respectively. The ratio of the flow rate of the heating water flowing through the branching passage 67 and the flow rate of the heating water flowing through the third high-pressure side branching passage 68c is adjusted.

  In addition, the control part 11 is the secondary refrigerant | coolant of the temperature requested | required in the radiator 61 based on the temperature etc. which the radiator temperature sensor 61T mentioned above, the intermediate pressure side branch path temperature sensor 67T, the high pressure side branch path temperature sensor 68T, etc. detect. The flow rate of the heating pump 63 and the diversion ratio in the heating mixing valve 64 are controlled.

(Hot water supply circuit 90)
The hot water supply circuit 90 circulates water for hot water supply. The hot water supply circuit 90 includes a hot water storage tank 91, a water supply pipe 94, a hot water supply pipe 98, a hot water supply bypass pipe 99, a hot water supply mixing valve 93, a hot water supply heat pump pipe 95, and a hot water supply pump 92.

  Although not shown, the hot water storage tank 91 is provided with a circulation outlet and a circulation return port. After passing outside city water (not shown), normal temperature water is supplied from the vicinity of the lower end of the hot water storage tank 91 into the hot water storage tank 91 via the water supply pipe 94. The hot water supply heat pump pipe 95 includes a first hot water supply heat pump pipe 95a, a second hot water supply heat pump pipe 95b, a third hot water supply heat pump pipe 95c, a fourth hot water supply heat pump pipe 95d, a fifth hot water supply heat pump pipe 95e, and a sixth hot water supply heat pump pipe 95f. Have.

  The first hot water supply heat pump pipe 95 a connects the circulation outlet of the hot water storage tank 91 and the hot water supply pump 92. The first hot water supply heat pump pipe 95a is provided with a hot water supply water temperature sensor 94T that detects the temperature of the hot water passing therethrough. The second hot water supply heat pump pipe 95b connects the hot water supply pump 92 and the upstream end in the direction of water flow in the hot water supply heat pump pipe 95 of the third high-pressure water heat exchanger 53. The third hot water supply heat pump pipe 95c allows the hot water supply water to flow through the third high pressure water heat exchanger so that it does not mix with carbon dioxide as the primary refrigerant flowing in the sixth high pressure pipe 27f. 53. Here, in the third high-pressure water heat exchanger 53, carbon dioxide as a primary refrigerant flowing in the sixth high-pressure pipe 27f and hot-water supply water flowing in the third hot-water supply heat pump pipe 95c are mutually connected. The counterflow type which is flowing in the opposite direction is adopted. The fourth hot water supply heat pump pipe 95d includes the downstream end in the flow direction of the water in the hot water supply heat pump pipe 95 of the third high pressure water heat exchanger 53 and the water in the hot water supply heat pump pipe 95 of the first high pressure water heat exchanger 51. To the upstream end in the flow direction. The fourth hot water supply heat pump pipe 95d is provided with a hot water supply intermediate temperature sensor 95T that detects the temperature of the hot water passing therethrough. In the second high-pressure water heat exchanger 52, heat exchange is not performed between water for hot water supply and carbon dioxide as a primary refrigerant. The fifth hot water supply heat pump pipe 95e flows the first hot water supply heat exchanger while flowing hot water therein so as not to be mixed with carbon dioxide as the primary refrigerant flowing in the second high pressure pipe 27b. Passing through 51. Here, in the first high-pressure water heat exchanger 51, carbon dioxide as the primary refrigerant flowing in the second high-pressure pipe 27b and hot-water supply water flowing in the fifth hot-water supply heat pump pipe 95e are mutually connected. The counterflow type which is flowing in the opposite direction is adopted. The sixth hot water supply heat pump pipe 95f connects the downstream end of the hot water supply heat pump pipe 95 of the first high-pressure water heat exchanger 51 in the flow direction of water with the circulation return port of the hot water storage tank 91. The sixth hot water supply heat pump pipe 95f is provided with a hot water supply hot water temperature sensor 98T that detects the temperature of the hot water passing therethrough.

  The hot water supply pipe 98 guides hot water stored in the hot water storage tank 91 from the vicinity of the upper end of the hot water storage tank 91 to a place where it is not shown. The water supply pipe 94 is provided with a water supply branch point W, which is a branch portion that branches off from the flow toward the hot water storage tank 91. The hot water supply pipe 98 is provided with a hot water supply junction point Z for joining the flow toward the place used from the hot water storage tank 91. The hot water supply bypass pipe 99 connects the water supply branch point W and the hot water supply junction point Z. The hot water supply junction point Z is provided with a hot water mixing valve 93 that can adjust the mixing ratio of hot water sent from the hot water storage tank 91 through the hot water supply pipe 98 and normal temperature water supplied from city water through the hot water supply bypass pipe 99. It has been. By adjusting the mixing ratio in the hot water supply mixing valve 93, the temperature of the water sent to the place where it is used is adjusted.

  The control unit 11 controls the flow rate of the hot water supply pump 92 based on the temperature detected by the hot water supply / water temperature sensor 94T, the hot water intermediate temperature sensor 95T, the hot water supply / hot water temperature sensor 98T, and the like.

<1-2> Operation of Heat Pump Circuit 10 FIG. 2 is a pressure-enthalpy diagram when the heat pump system 1 is operated. FIG. 3 is a temperature-entropy diagram when the heat pump system 1 is operated.

  Hereinafter, the temperature distribution state of the primary refrigerant will be described with one specific example.

  The low-stage compressor 21 compresses the primary refrigerant (point A) of about 22 ° C. flowing through the low-pressure pipe 20 so that the target discharge temperature reaches about 90 ° C. (point B). Here, the pressure of the primary refrigerant flowing through the low-pressure pipe 20 is reduced to the pressure (evaporation) until the pressure at which the carbon dioxide as the primary refrigerant can be evaporated by the ambient temperature where the evaporator 4 is installed. The pressure is adjusted by the control unit 11.

  The primary refrigerant discharged from the low-stage compressor 21 flows into the second intermediate pressure pipe 23b in the intermediate pressure water heat exchanger 40 through the first intermediate pressure pipe 23a. The primary refrigerant flowing into the intermediate pressure water heat exchanger 40 is cooled to about 35 ° C. by exchanging heat with water as the secondary refrigerant for heating passing through the second intermediate pressure side branch passage 67b. (Point C). Here, since the primary refrigerant and the secondary refrigerant in the intermediate-pressure water heat exchanger 40 flow in a counterflow manner, in the vicinity of the outlet of the second intermediate-pressure pipe 23b in the intermediate-pressure water heat exchanger 40, the radiator 61 It is cooled effectively by a secondary refrigerant of about 30 ° C. in a state of being cooled by releasing heat.

  The primary refrigerant that has passed through the intermediate pressure water heat exchanger 40 is further cooled by joining with the primary refrigerant of about 27 ° C. that flows in through the injection passage 70 at the injection junction D of the third intermediate pressure pipe 23c, It becomes about 30 ° C. (point D). Here, the control unit 11 performs control so that the primary refrigerant after joining at the injection joining point D has a superheat degree or is in a supercritical state. Further, the control unit 11 drives the high-stage compressor 25 while driving the high-stage compressor 25 at the same compression ratio as that of the low-stage compressor 21 after the primary refrigerant merged at the injection junction D. Control is performed so that the target temperature of the primary refrigerant discharged from the side compressor 25 can be 90 ° C., which is the same as the target temperature of the primary refrigerant discharged from the low-stage compressor 21. Further, the control unit 11 controls the primary refrigerant sucked into the high-stage compressor 25 so as to adjust the heat balance in the intermediate pressure water heat exchanger 40 and the injection path 70.

  The primary refrigerant joined at the injection junction D is sucked into the high-stage compressor 25 so that the target discharge temperature reaches about 90 ° C., which is the same temperature as the target temperature of the discharge refrigerant of the low-stage compressor 21. Further, the primary refrigerant is compressed. Here, the high-stage compressor 25 is controlled by the control unit 11 so as to compress until the discharge refrigerant pressure of the primary refrigerant reaches a pressure exceeding the supercritical pressure of the primary refrigerant (point E).

  The primary refrigerant discharged by the high-stage compressor 25 flows into the second high-pressure pipe 27b in the first high-pressure water heat exchanger 51 through the first high-pressure pipe 27a. The primary refrigerant that has flowed into the first high-pressure water heat exchanger 51 is cooled to about 85 ° C. by exchanging heat with the hot-water supply water passing through the fifth hot-water supply heat pump pipe 95e. F). Since the primary refrigerant radiates heat while maintaining a state where the critical pressure is exceeded, the temperature continuously changes. Here, since the primary refrigerant and the secondary refrigerant in the first high-pressure water heat exchanger 51 are flowing in a counterflow manner, they are still near the outlet of the second high-pressure pipe 27b in the first high-pressure water heat exchanger 51. It is cooled effectively by water for hot water supply of about 30 ° C. that is not sufficiently heated.

  The primary refrigerant that has passed through the first high-pressure water heat exchanger 51 flows into the fourth high-pressure pipe 27d in the second high-pressure water heat exchanger 52 through the third high-pressure pipe 27c. The primary refrigerant that has flowed into the second high-pressure water heat exchanger 52 exchanges heat with water as a secondary refrigerant for heating that passes through the second high-pressure side branch 68b, so that the temperature becomes approximately 35 ° C. It is cooled (point G). Here, since the primary refrigerant and the secondary refrigerant in the second high-pressure water heat exchanger 52 are flowing in a counterflow manner, in the vicinity of the outlet of the fourth high-pressure pipe 27d in the second high-pressure water heat exchanger 52, the radiator 61 is effectively cooled by the secondary refrigerant of about 30 ° C. in a state of being cooled by releasing heat.

  The primary refrigerant that has passed through the second high-pressure water heat exchanger 52 flows into the sixth high-pressure pipe 27f in the third high-pressure water heat exchanger 53 through the fifth high-pressure pipe 27e. The primary refrigerant that has flowed into the third high-pressure water heat exchanger 53 is further cooled to about 30 ° C. by exchanging heat with water for hot water passing through the third hot water supply heat pump pipe 95c. (Point H). Here, since the primary refrigerant and the secondary refrigerant in the third high-pressure water heat exchanger 53 flow in a counterflow manner, hot water storage is performed in the vicinity of the outlet of the sixth high-pressure pipe 27 f in the third high-pressure water heat exchanger 53. By mixing in the tank 91, it is effectively cooled by hot water supply water of about 20 ° C., which is a level slightly raised from the temperature of city water. The primary refrigerant that has passed through the third high-pressure water heat exchanger 53 reaches the third high-pressure point H through the seventh high-pressure pipe 27g.

  Here, the high-pressure water heat exchanger 50 is divided into three heat exchangers, and since the primary refrigerant flowing through the high-pressure water heat exchanger 50 is in a bicritical state, a temperature change occurs in the heat dissipation process, and The temperature change range (30 ° C. to 65 ° C.) of water as a secondary refrigerant circulating in the heating circuit 60 is included in the temperature change range (20 ° C. to 90 ° C.) of hot water for the hot water supply circuit 90. And, in order to correspond to this temperature distribution, heat exchange with the primary refrigerant in a relatively high temperature state and heat exchange with the primary refrigerant in a relatively low temperature state among the primary refrigerants discharged from the high-stage compressor 25, Is assigned to heat exchange for hot water supply, and heat exchange with the primary refrigerant in the intermediate temperature state is assigned to heat exchange with the secondary refrigerant for heating. As a result, not only in heat exchange between the primary refrigerant and water for hot water supply but also in heat exchange between the primary refrigerant and water for heating, the temperature difference between the fluids that perform heat exchange can be kept small, The exchange efficiency can be improved.

  The primary refrigerant that has reached the third high pressure point H is divided into a flow toward the expansion valve 5a and a flow toward the injection path 70 through the eighth high pressure pipe 27h. The degree of the diversion here is controlled by the control unit 11 adjusting the valve opening degree of the injection expansion valve 73. The primary refrigerant that is diverted to the injection passage 70 side is reduced in pressure at the injection expansion valve 73 after passing through the first injection pipe 72, and the temperature of the primary refrigerant is lowered to about 23 ° C. (point Q).

  The primary refrigerant decompressed in the injection expansion valve 73 flows into the third injection pipe 75 in the economizer heat exchanger 7 through the second injection pipe 74. The primary refrigerant that has flowed into the economizer heat exchanger 7 exchanges heat with the primary refrigerant of about 30 ° C. flowing through the ninth high-pressure pipe 27i, and is heated to about 27 ° C. (point R).

  The primary refrigerant of about 27 ° C. that has passed through the third injection pipe 75 in the economizer heat exchanger 7 joins with the primary refrigerant flowing through the intermediate pressure pipe 23 at the injection junction D described above through the fourth injection pipe 76. .

  Of the primary refrigerant that has reached the third high pressure point H, the primary refrigerant of about 30 ° C. that does not flow to the injection passage 70 side flows into the ninth high pressure pipe 27i in the economizer heat exchanger 7 through the eighth high pressure pipe 27h. To do. As described above, the primary refrigerant that has flowed into the ninth high-pressure pipe 27i in the economizer heat exchanger 7 exchanges heat with the primary refrigerant that flows through the third injection pipe 75 at about 27 ° C. Then, it is further cooled to about 25 ° C. (point I). The primary refrigerant that has passed through the ninth high-pressure pipe 27i in the economizer heat exchanger 7 reaches the fourth high-pressure point I through the tenth high-pressure pipe 27j.

  The primary refrigerant that has reached the fourth high-pressure point I is divided into a flow toward the primary bypass 80 and a flow toward the eleventh high-pressure tube 27k. The degree of diversion here is adjusted by the control unit 11 controlling the valve opening degree of the primary bypass expansion valve 5b. The primary refrigerant that has flowed through the eleventh high-pressure pipe 27k flows into the twelfth high-pressure pipe 27l in the primary refrigerant heat exchanger 8. The primary refrigerant that has flowed into the twelfth high-pressure pipe 271 in the primary inter-refrigerant heat exchanger 8 exchanges heat with the primary refrigerant that flows through the fourth low-pressure pipe 20d to about -3 ° C. Cool to the extent (point J).

  The primary refrigerant that has passed through the twelfth high-pressure pipe 12 in the primary inter-refrigerant heat exchanger 8 flows to the expansion valve 5a through the thirteenth high-pressure pipe 27m. In the expansion valve 5a, the degree of decompression of the primary refrigerant that passes through is adjusted by adjusting the valve opening degree by the control unit 11, the refrigerant pressure of the primary refrigerant that passes through decreases, and the refrigerant temperature also decreases to about -3 ° C ( Point K). Here, the primary refrigerant is depressurized to a pressure equal to or lower than the critical pressure by adjusting the degree of depressurization by the control unit 11, and enters a gas-liquid two-phase state.

  In the heat pump circuit 10, the primary refrigerant can be cooled not only by the economizer heat exchanger 7 but also by the primary refrigerant heat exchanger 8. In the cooling of the primary refrigerant flowing through the primary inter-refrigerant heat exchanger 8, the primary refrigerant on the suction side of the low-stage compressor 21 in which the primary refrigerant having the lowest temperature flows in the heat pump circuit 10 can be used. Thereby, the density of the primary refrigerant passing through the expansion valve 5a can be increased, and the circulation amount of the primary refrigerant in the heat pump circuit 10 can be increased.

  The primary refrigerant that has passed through the expansion valve 5a flows to the third low-pressure point M through the first low-pressure pipe 20a, and joins the primary refrigerant that flows through the sixth low-pressure pipe 20f (point M).

  Of the primary refrigerant that has reached the fourth high-pressure point I, the primary refrigerant of about 25 ° C. that does not flow to the eleventh high-pressure pipe 27k side flows to the primary bypass 80 side, and the primary bypass expansion through the fourteenth high-pressure pipe 27n. It flows to the valve 5b. The primary bypass expansion valve 5b is adjusted by the control unit 11 so that the degree of pressure reduction of the primary refrigerant passing through is adjusted, the refrigerant pressure of the primary refrigerant passing through is lowered, and the refrigerant temperature is also about -3 ° C. Lower (point L). Here, similarly to the point K, the primary refrigerant is depressurized to a pressure equal to or lower than the critical pressure by adjusting the depressurization degree by the control unit 11, and becomes a gas-liquid two-phase state.

  The primary refrigerant that has passed through the primary bypass expansion valve 5b flows through the sixth low-pressure pipe 20f to the third low-pressure point M, and merges with the primary refrigerant that has flowed through the first low-pressure pipe 20a described above (point M).

  The primary refrigerant of about −3 ° C. joined at the third low pressure point M flows into the evaporator 4 through the second low pressure pipe 20b. The primary refrigerant that has flowed into the evaporator 4 exchanges heat with the air that is actively supplied to the evaporator 4 by the fan 4f. By the heat exchange in the evaporator 4, the primary refrigerant in a gas-liquid two-phase state of about −3 ° C. evaporates while maintaining the temperature constant (by changing the latent heat), and the dryness increases. A state close to saturation is reached (point N).

  The primary refrigerant that has passed through the evaporator 4 flows into the fourth low-pressure pipe 20d in the primary inter-refrigerant heat exchanger 8 through the third low-pressure pipe 20c. As described above, the primary refrigerant flowing through the fourth low-pressure pipe 20d in the inter-primary refrigerant heat exchanger 8 exchanges heat with the primary refrigerant of about 25 ° C. flowing through the twelfth high-pressure pipe 27l. By carrying out, it will be heated to about 22 degreeC and will be in the state with the degree of superheat (point A).

  The primary refrigerant that has passed through the fourth low-pressure pipe 20d in the primary refrigerant heat exchanger 8 becomes overheated and is sucked into the low-stage compressor 21.

  In the heat pump circuit 10, the primary refrigerant circulates as described above.

<1-3> Operation of heating circuit 60 In order to warm the space in which the radiator 61 is installed, the control unit 11 performs control so that water as a secondary refrigerant at about 65 ° C. is supplied to the radiator 61. Is going.

  Hereinafter, the temperature distribution state of the secondary refrigerant for heating will be described with one specific example.

  The water as the secondary refrigerant for heating that has dissipated heat while passing through the radiator 61 drops to a temperature of about 35 ° C., depending on the performance of the radiator 61 and the degree of the heating load, and passes through the heating return pipe 66. It flows to the heating branch point X.

  The heating branch point X is divided into a flow toward the intermediate pressure side branch 67 and a flow toward the high pressure side branch 68.

  The secondary refrigerant that flows from the heating branch point X toward the intermediate pressure side branch path 67 side flows into the second intermediate pressure side branch path 67b in the intermediate pressure water heat exchanger 40 through the first intermediate pressure side branch path 67a. Go. As described above, the secondary refrigerant flowing through the second intermediate pressure side branch passage 67b in the intermediate pressure water heat exchanger 40 is heated by the primary refrigerant passing through the second intermediate pressure pipe 23b, so The temperature of the secondary refrigerant is raised to about 65 ° C. Note that, as described above, the primary refrigerant and the secondary refrigerant in the intermediate pressure water heat exchanger 40 flow in a counterflow manner, and thus the second intermediate pressure side branch path 67b in the intermediate pressure water heat exchanger 40. The vicinity of the outlet is efficiently heated by a primary refrigerant of about 90 ° C., which is a relatively high temperature. Then, the secondary refrigerant that has passed through the second intermediate pressure side branch passage 67b in the intermediate pressure water heat exchanger 40 and has been warmed to about 65 ° C. passes through the third intermediate pressure side branch passage 67c and passes through the heating junction point Y. It will flow to.

  The secondary refrigerant that has flowed from the heating branch point X toward the high pressure side branch path 68 side flows into the second high pressure side branch path 68b in the second high pressure water heat exchanger 52 through the first high pressure side branch path 68a. To go. As described above, the secondary refrigerant flowing through the second high-pressure side branch 68b in the second high-pressure water heat exchanger 52 is heated by the primary refrigerant passing through the fourth high-pressure pipe 27d, so that the temperature of about 30 ° C. The temperature of the secondary refrigerant is raised to about 65 ° C. Note that, as described above, the primary refrigerant and the secondary refrigerant in the second high-pressure water heat exchanger 52 flow in a counterflow manner, and therefore the second high-pressure side branch in the second high-pressure water heat exchanger 52. The vicinity of the outlet of the path 68b is efficiently heated by a primary refrigerant of about 85 ° C., which is a relatively high temperature. Then, the secondary refrigerant that has passed through the second high-pressure side branch path 68b in the second high-pressure water heat exchanger 52 and has been warmed to about 65 ° C. passes through the third high-pressure side branch path 68c and passes through the heating junction point. It flows to Y.

  At the heating junction Y, the secondary refrigerant that has passed through the third intermediate pressure side branch 67c and the secondary refrigerant that has passed through the third high pressure side branch 68c merge. The control unit 11 adjusts the valve opening degree on the intermediate pressure side branch path 67 side and the valve opening degree on the high pressure side branch path 68 side in the heating mixing valve 64 so that the two flowing through the intermediate pressure side branch path 67 side. The flow rate of the secondary refrigerant and the flow rate of the secondary refrigerant flowing through the high-pressure side branch path 68 can be adjusted. As a result, the control unit 11 determines that the secondary refrigerant circulating in the heating circuit 60 is heated on the intermediate pressure water heat exchanger 40 side and heated on the second high pressure water heat exchanger 52 side. By controlling the flow rate of the secondary refrigerant passing through the heating pump 63 while adjusting the ratio, the temperature of the secondary refrigerant joined at the heating junction Y is controlled to be the temperature required by the radiator 61. Can do.

  In this way, the secondary refrigerant heated to about 65 ° C. joined at the heating junction Y is supplied to the radiator 61 through the heating forward pipe 65. In the heating circuit 60, the secondary refrigerant circulates as described above.

<1-4> Operation of Hot Water Supply Circuit 90 The control unit 11 controls the flow rate of the hot water supply pump 92 so that hot water of about 90 ° C. can be stored in the hot water storage tank 91.

  Hereinafter, the temperature distribution state of hot water supply water will be described with one specific example.

  The relatively low temperature water below the hot water storage tank 91 into which the city water has flowed flows toward the hot water supply heat pump pipe 95 at a temperature of about 20 ° C.

  The hot water supply water at about 20 ° C. that has passed through the first hot water supply heat pump pipe 95 a and the second hot water supply heat pump pipe 95 b flows into the third hot water supply heat pump pipe 95 c in the third high-pressure water heat exchanger 53. As described above, the water for hot water flowing through the third hot water supply heat pump pipe 95c in the third high pressure water heat exchanger 53 passes through the sixth high pressure pipe 27f in the third high pressure water heat exchanger 53 at about 35 ° C. When heated by the primary refrigerant, the temperature of water for hot water supply at about 20 ° C. is raised to about 30 ° C. Note that, as described above, the primary refrigerant and the secondary refrigerant in the third high-pressure water heat exchanger 53 flow in a counterflow manner, and thus the third hot water supply heat pump pipe in the third high-pressure water heat exchanger 53. The vicinity of the outlet of 95c is efficiently heated by the primary refrigerant at a relatively high temperature of about 35 ° C.

  The hot-water supply water heated to about 30 ° C. in the third high-pressure water heat exchanger 53 passes through the fourth hot-water supply heat pump pipe 95d and enters the fifth hot-water supply heat pump pipe 95e in the first high-pressure water heat exchanger 51. Inflow. As described above, the hot-water supply water flowing through the fifth hot-water supply heat pump pipe 95e in the first high-pressure water heat exchanger 51 passes through the second high-pressure pipe 27b in the first high-pressure water heat exchanger 51 at about 90 ° C. When heated by the primary refrigerant, the temperature of the hot water supply at about 30 ° C. is raised to about 90 ° C. Note that, as described above, the primary refrigerant and the secondary refrigerant in the first high-pressure water heat exchanger 51 flow in a counterflow manner, and thus the fifth hot water supply heat pump pipe in the first high-pressure water heat exchanger 51. The vicinity of the outlet of 95e is efficiently heated by a primary refrigerant of about 90 ° C., which is a relatively high temperature.

  The hot water supply water heated to about 90 ° C. in the first high-pressure water heat exchanger 51 passes through the sixth hot water supply heat pump pipe 95 f and flows into the hot water storage tank 91.

  Thus, the temperature of the hot water stored in the hot water storage tank 91 can be raised by circulating the hot water in the hot water supply circuit 90.

<1-5> Secondary Refrigerant Temperature Unified Control As described above, with respect to the heat pump circuit 10, the control unit 11 can cope with not only the heating load of the heating circuit 60 but also the hot water supply load of the hot water supply circuit 90. The operation is carried out so that the cycle efficiency can be kept as good as possible while supplying a sufficient amount of heat to each circuit. In addition, about the heating circuit 60, specifically, the control part 11 is the temperature of the secondary refrigerant | coolant for heating which the temperature of the primary refrigerant | coolant which flows in into the intermediate pressure water heat exchanger 40 flows into the intermediate pressure water heat exchanger 40. The temperature of the primary refrigerant flowing into the second high-pressure water heat exchanger 52 is set to be higher than the temperature of the secondary refrigerant for heating flowing into the second high-pressure water heat exchanger 52. However, the temperature of the primary refrigerant flowing into the intermediate-pressure water heat exchanger 40 and the temperature of the primary refrigerant flowing into the second high-pressure water heat exchanger 52 are both higher than the temperature required by the radiator 61. Control of the low stage side compressor 21, the high stage side compressor 25, the expansion valve 5a, etc. is performed.

  Then, the control unit 11 makes the first high-pressure water heat from the target discharge temperature of the high-stage compressor 25 while making the target discharge temperature of the low-stage compressor 21 higher than the temperature required in the radiator 61. Control is performed so that the temperature after subtracting the heat released when passing through the exchanger 51 is higher than the temperature required in the radiator 61. In addition, the control unit 11 determines the evaporation temperature based on the installation environment of the evaporator 4 and equalizes the compression ratio of the low-stage compressor 21 and the compression ratio of the high-stage compressor 25 with the smallest possible compression ratio. Control is performed so as to be. In order to meet these purposes, the control unit 11 specifically includes the low-stage compressor 21, the high-stage compressor 25, the expansion valve 5a, the injection expansion valve 73, and the primary bypass expansion of the heat pump circuit 10. Control of the valve 5b and the fan 4f is performed. In addition, when the temperature of the primary refrigerant becomes too high, the control unit 11 applies to the inner wall surface of the pipe through which the secondary refrigerant for heating that performs heat exchange flows or the inner wall surface of the water for hot water supply that performs heat exchange. Since scales (scales, etc.) may occur, the temperature of the primary refrigerant is controlled to be equal to or lower than a predetermined high temperature limit value.

  While making it possible to maintain the above-described operation state with good cycle efficiency on the heat pump circuit 10 side as much as possible, the control unit 11 controls the temperature of the secondary refrigerant flowing through the third intermediate pressure side branch path 67c of the heating circuit 60 and the first temperature. The secondary refrigerant temperature unified control is performed so that the temperature of the secondary refrigerant flowing through the three high-pressure side branch paths 68c becomes the same temperature. The control unit 11 not only performs control so that the temperature of the secondary refrigerant flowing through the third intermediate pressure side branch 67c and the temperature of the secondary refrigerant flowing through the third high pressure side branch 68c are unified. The control is performed so that the unified temperature coincides with the temperature required in the radiator 61. Specifically, the control unit 11 controls the mixing ratio of the heating mixing valve 64 to control the flow rate of the secondary refrigerant for heating that flows through the intermediate pressure side branch passage 67 and the secondary for heating that flows through the high pressure side branch passage 68. Requested in the radiator 61 by mixing ratio control for adjusting the ratio with the flow rate of the refrigerant, and flow rate control for adjusting the flow rate of the secondary refrigerant for heating supplied to the radiator 61 by controlling the flow rate of the heating pump 63. Unify at the specified temperature.

  In order to make the temperature of the secondary refrigerant for heating flowing through the third intermediate pressure side branch passage 67c the same as the temperature of the secondary refrigerant for heating flowing through the third high pressure side branch passage 68c, the control unit 11 Of the temperature detected by the intermediate pressure side branch temperature sensor 67T and the temperature detected by the high pressure side branch temperature sensor 68T, the flow rate of the secondary refrigerant on the low temperature side decreases and the flow rate of the secondary refrigerant on the high temperature side increases. Thus, the heating mixing valve 64 is controlled. As a result, for the secondary refrigerant on the low temperature side, the flow rate is lowered by reducing the flow rate, and the time during which the secondary refrigerant receives heat from the primary refrigerant in the heat exchange with the primary refrigerant can be lengthened. Will go up. On the other hand, for the secondary refrigerant on the high temperature side, the flow rate is increased by increasing the flow rate, and the time during which the secondary refrigerant receives heat from the primary refrigerant in the heat exchange with the primary refrigerant can be shortened, and the temperature is increased. Will go down. Thus, the difference between the temperature of the secondary refrigerant for heating flowing through the third intermediate pressure side branch passage 67c and the temperature of the secondary refrigerant for heating flowing through the third high pressure side branch passage 68c becomes small. It will follow.

  Here, the temperature required in the radiator 61 refers to a temperature value having a certain range as described below.

  In the heating circuit 60, the amount of heat released by the radiator 61 for the secondary refrigerant for heating required by the user can be set and input. And the control part 11 controls the heating mixing valve 64 and the heating pump 63 so that the thermal radiation amount with the radiator 61 which a user requests | requires can be ensured. Specifically, as control for securing the amount of heat radiation required in the radiator 61, when the flow rate of the secondary refrigerant for heating passing through the heating pump 63 is increased and the temperature of the secondary refrigerant for heating is kept low. In some cases, the temperature of the secondary refrigerant for heating is increased while the flow rate of the secondary refrigerant for heating passing through the heating pump 63 is decreased. That is, in the case where the same amount of heat is ensured, the temperature required as the temperature of the secondary refrigerant for heating when the flow rate of the heating pump 63 is increased to a certain value, the flow rate of the heating pump 63 is less than this certain value. When the temperature is decreased, the temperature becomes lower than the temperature required as the temperature of the secondary refrigerant for heating. On the contrary, when the same amount of heat is ensured, the temperature required as the temperature of the secondary refrigerant for heating when the flow rate of the heating pump 63 is reduced to another value is the same as the flow rate of the heating pump 63. When the value is larger than the above value, the temperature becomes higher than the temperature required as the temperature of the secondary refrigerant for heating. Further, the temperature of the secondary refrigerant supplied to the radiator 61 is detected by the ambient temperature of the radiator 61 (the radiator temperature sensor 61T) because the purpose is to warm the air in the surrounding space where the radiator 61 is installed. Temperature). The temperature required in the radiator 61 is higher than the temperature detected by the radiator temperature sensor 61T in this way, and has a temperature range corresponding to the flow rate range in which the amount of heat radiation required in the radiator 61 can be secured. Yes. Further, the temperature range may be limited by reflecting the heat radiation performance of the radiator 61 itself.

  The temperature of the secondary refrigerant for heating that flows toward the radiator 61 through the heating forward pipe 65 is equal to the secondary refrigerant for heating that has flowed through the intermediate pressure side branch path 67 and the heating secondary refrigerant that has flowed through the high pressure side branch path 68. The temperature after the secondary refrigerant merges at the heating merge point Y.

  For this reason, when the temperature of the secondary refrigerant flowing through the third intermediate pressure side branch path 67c and the temperature of the secondary refrigerant flowing through the third high pressure side branch path 68c are the same temperature, the heating confluence point Y The temperature of the secondary refrigerant after merging is also the same as the temperature before merging, and is the temperature of the secondary refrigerant for heating supplied toward the radiator 61.

(Energy increase processing)
When the temperature unified by the secondary refrigerant temperature unified control is less than the temperature required in the radiator 61 while performing the secondary refrigerant temperature unified control, the control unit 11 reduces the flow rate of the heating pump 63. Perform heat increase control.

  Thereby, it is possible to decrease both the flow rate of the secondary refrigerant flowing through the intermediate pressure side branch passage 67 and the flow rate of the secondary refrigerant flowing through the high pressure side branch passage 68. As a result, both the time for which the secondary refrigerant flowing through the intermediate pressure side branch passage 67 receives heat from the primary refrigerant and the time for the secondary refrigerant flowing through the high pressure side branch passage 68 to receive heat from the primary refrigerant are selected. Can also be long. As a result, the temperature of the secondary refrigerant for heating flowing through the third intermediate pressure side branch passage 67c and the temperature of the secondary refrigerant for heating flowing through the third high pressure side branch passage 68c are set at the temperatures required by the radiator 61. Therefore, the heat load on the radiator 61 can be dealt with.

(Heat reduction processing)
When the temperature unified by the secondary refrigerant temperature unified control exceeds the temperature required in the radiator 61 while performing the secondary refrigerant temperature unified control, the controller 11 controls the flow rate of the heating pump 63. Control to reduce the amount of heat.

  Thereby, it is possible to increase both the flow velocity of the secondary refrigerant flowing through the intermediate pressure side branch passage 67 and the flow velocity of the secondary refrigerant flowing through the high pressure side branch passage 68. As a result, both the time for which the secondary refrigerant flowing through the intermediate pressure side branch passage 67 receives heat from the primary refrigerant and the time for the secondary refrigerant flowing through the high pressure side branch passage 68 to receive heat from the primary refrigerant are selected. Can also be kept short. As a result, the temperature of the secondary refrigerant for heating flowing through the third intermediate pressure side branch passage 67c and the temperature of the secondary refrigerant for heating flowing through the third high pressure side branch passage 68c are set at the temperatures required by the radiator 61. Therefore, the heat load on the radiator 61 can be dealt with.

<1-6> Features of First Embodiment In the heat pump system 1 of the first embodiment, the control unit 11 flows through the temperature of the secondary refrigerant flowing through the third intermediate pressure side branch passage 67c and the third high pressure side branch passage 68c. Control is performed so that the temperature of the secondary refrigerant is unified. Here, the secondary refrigerant flowing through the third intermediate pressure side branch passage 67c and the secondary refrigerant flowing through the third high pressure side branch passage 68c both have a lower temperature until they reach the radiator 61. Heat is dissipated, resulting in heat dissipation loss. However, in the heat pump system 1 of the first embodiment, not only the temperature of the secondary refrigerant flowing through the third intermediate pressure side branch 67c but also the temperature of the secondary refrigerant flowing through the third high pressure side branch 68c becomes too high. The difference from the ambient temperature can be kept small. For this reason, not only the temperature of the secondary refrigerant flowing through the third intermediate pressure side branch passage 67c but also the temperature of the secondary refrigerant flowing through the third high pressure side branch passage 68c can suppress the heat dissipation loss to the surroundings. Yes.

  Further, the control unit 11 unifies the temperature of the secondary refrigerant flowing through the third intermediate pressure side branch passage 67c and the temperature of the secondary refrigerant flowing through the third high pressure side branch passage 68c at the temperature required in the radiator 61. Control is performed so that For this reason, it is not necessary to perform temperature adjustment by heating or cooling so that the temperature of the secondary refrigerant for heating after merging at the heating merging point Y becomes the temperature required by the radiator 61. Thereby, such a temperature control heater or a cooler can be made unnecessary.

  In the heat pump circuit 10 in the heat pump system 1 of the first embodiment, the primary refrigerant sucked by the high stage compressor 25 is cooled by the secondary refrigerant for heating when passing through the intermediate pressure water heat exchanger 40. The primary refrigerant flowing through the injection passage 70 is further cooled. For this reason, the density of the primary refrigerant sucked by the high-stage compressor 25 can be increased, and the efficiency of the heat pump circuit 10 can be improved.

  Furthermore, the heat obtained by the secondary refrigerant for heating by cooling the primary refrigerant sucked into the high-stage compressor 25 can be used for the heating load in the radiator 61.

  Further, even when the heat necessary for raising the hot water supply water to the required water temperature is obtained from the primary refrigerant flowing through the high-pressure water heat exchanger 50, the primary refrigerant flowing through the high-pressure water heat exchanger 50 still remains. The temperature is in a temperature range in which the secondary refrigerant for heating can be heated. For this reason, within the range in which the operation efficiency of the heat pump circuit 10 can be improved, the heat of the primary refrigerant flowing through the second high-pressure water heat exchanger 52 that is a part of the high-pressure water heat exchanger 50 is heated. It can be effectively used to heat the secondary refrigerant. As a result, the heat of the primary refrigerant flowing through the high-pressure water heat exchanger 50 can be effectively utilized while improving the operation efficiency of the heat pump circuit 10.

  For example, when the secondary refrigerant for heating or the water for hot water supply is heated by the intermediate pressure water heat exchanger 40 and then further heated by the high pressure water heat exchanger 50, the high pressure water heat exchanger 50 is used. Since the secondary refrigerant for heating or the water for hot water supply that is about to flow into the water has already been warmed, the heat of the primary refrigerant flowing through the high-pressure water heat exchanger 50 cannot be used effectively. That is, the enthalpy change in the heat release process of the primary refrigerant cannot be sufficiently taken on the Mollier diagram. Similarly, when the secondary refrigerant for heating or the water for hot water supply is heated by the intermediate pressure water heat exchanger 40 after being heated by the high pressure water heat exchanger 50, the intermediate pressure water heat exchanger 40 is used. Since the secondary refrigerant for heating or the water for hot water supply to be inflowed is already warmed, the heat of the primary refrigerant flowing through the intermediate pressure water heat exchanger 40 cannot be fully utilized, and the multistage compression type It may be difficult to improve the operation efficiency of the heat pump circuit 10. On the other hand, in the heat pump system 1 of the first embodiment, in the heat pump circuit 10, the secondary refrigerant cooled in the radiator 61 is divided, and the intermediate pressure water heat exchanger 40 is passed through the intermediate pressure side branch passage 67. And heating performed by the second high-pressure water heat exchanger 52 while passing through the high-pressure side branch 68. As a result, the secondary refrigerant that has been cooled by the radiator 61 and has not yet been heated can be supplied to the intermediate-pressure water heat exchanger 40 and the second high-pressure water heat exchanger 52. As a result, the heat of the primary refrigerant flowing through the intermediate pressure pipe 23 can be sufficiently effectively utilized while improving the cooling effect of the primary refrigerant sucked by the high-stage compressor 25.

<2> Second Embodiment As shown in FIG. 4, the heat pump system 201 of the second embodiment includes a primary bypass 80 (fourteenth high-pressure pipe 27 n, primary bypass expansion valve 5 b, first bypass) in the heat pump system 1 of the first embodiment. 6 is a system in which all of the circulating primary refrigerant passes through the primary inter-refrigerant heat exchanger 8 without providing the low pressure pipe 20f). Since other configurations are the same as those in the first embodiment, description thereof is omitted.

  In the use environment where it is difficult to cause problems in capacity and efficiency even if all of the primary refrigerant circulating in the heat pump circuit 10 is subjected to heat exchange in the primary refrigerant heat exchanger 8, not only the number of parts can be reduced, but also the primary bypass. Control of the expansion valve 5b becomes unnecessary.

<3> Third Embodiment As shown in FIG. 5, in the heat pump system 301 of the third embodiment, the primary refrigerant is not injected into the intermediate pressure pipe 23, and the cooling of the primary refrigerant flowing through the intermediate pressure pipe 23 is performed by intermediate pressure water heat. This is a system that is performed entirely in the exchanger 40. That is, the heat pump system 301 of the third embodiment is similar to the heat pump system 1 of the first embodiment in that the economizer heat exchanger 7 and the injection path 70 (the injection expansion valve 73, the first injection pipe 72, the second injection pipe 74, the first 3 injection pipe 75, fourth injection pipe 76), eighth high pressure pipe 27h, ninth high pressure pipe 27i, tenth high pressure pipe 27j, third intermediate pressure pipe 23c, and fourth intermediate pressure pipe 23d are provided instead. And a 33rd intermediate pressure pipe 323c and a 38th high pressure pipe 327h. The 33rd intermediate pressure pipe 323c connects the second intermediate pressure pipe 23b in the intermediate pressure water heat exchanger 40 and the suction side of the high-stage compressor 25. The thirty-eighth high pressure pipe 327h connects the sixth high pressure pipe 27f in the third high pressure hydrothermal exchanger 53 and the fourth high pressure point I. Since other configurations are the same as those in the first embodiment, description thereof is omitted.

  In this heat pump system 301, it is possible to avoid a state where the refrigerant sucked by the high-stage compressor 25 is so cooled that the refrigerant becomes wet, and the circuit configuration can be simplified by reducing the number of components. .

  Moreover, in this heat pump system 301, since the injection path 70 is not provided, even if the temperature of the primary refrigerant passing through the intermediate pressure water heat exchanger 40 is excessively lowered by the secondary refrigerant temperature unified control, the higher stage side It becomes possible to increase the amount of the primary refrigerant toward the high-pressure water heat exchanger 50 within a range in which the primary refrigerant sucked by the compressor 25 does not become wet.

<4> Fourth Embodiment A heat pump system 401 according to a fourth embodiment is a system in which a branch to the injection path 70 side is arranged on the downstream side of the economizer heat exchanger 7 as shown in FIG. That is, in the heat pump system 401 of the fourth embodiment, in the heat pump system 1 of the first embodiment, the 43rd high pressure point 4H is replaced with the third high pressure point H, and the 47th high pressure tube 427g is replaced with the seventh high pressure pipe 27g. 48th high-pressure pipe 427h instead of the eighth high-pressure pipe 27h, 49th high-pressure pipe 427i instead of the ninth high-pressure pipe 27i, and 410th high-pressure pipe 427j instead of the tenth high-pressure pipe 27j, respectively. System. The 43rd high pressure point 4H is provided downstream of the economizer heat exchanger 7 and upstream of the fourth high pressure point I in the flow direction of the primary refrigerant in the heat pump circuit 10, and the injection path 70 branches off. Yes. The 47th high pressure pipe 427g connects the sixth high pressure pipe 27f in the third high pressure water heat exchanger 53 and the 48th high pressure pipe 427h in the economizer heat exchanger 7. The 49th high pressure pipe 427i connects the 48th high pressure pipe 427h in the economizer heat exchanger 7 and the 43rd high pressure point 4H. The 410th high pressure pipe 427j connects the 43rd high pressure point 4H and the fourth high pressure point I. Since other configurations are the same as those in the first embodiment, description thereof is omitted.

  In this heat pump system 401, the temperature of the primary refrigerant flowing through the injection path 70 can be made lower than that of the primary refrigerant flowing through the injection path 70 of the heat pump system 1 of the first embodiment. The cooling effect can be improved.

<5-1> Fifth Embodiment A heat pump system 501 of the fifth embodiment is a system in which the third high-pressure water heat exchanger 53 is removed from the heat pump system 1 of the first embodiment, as shown in FIG. That is, the heat pump system 501 of the fifth embodiment is the same as the heat pump system 1 of the first embodiment, except that the second hot water supply heat pump pipe 95b, the third hot water supply heat pump pipe 95c, and the fourth hot water supply heat pump pipe 95d are replaced with the 52nd hot water supply heat pump pipe. 595b is a system in which a 55th high-pressure pipe 527e is provided instead of the fifth high-pressure pipe 27e, the sixth high-pressure pipe 27f, and the seventh high-pressure pipe 27g. Here, the hot water supply intermediate temperature sensor 95T used in the heat pump system 1 of the first embodiment is not necessary. The 52nd hot water supply heat pump pipe 595b connects the hot water supply pump 92 and the upstream end of the fifth hot water supply heat pump pipe 95e in the first high pressure water heat exchanger 51 in the flow of hot water. . The 55th high-pressure pipe 527e connects the downstream side end in the flow direction of the primary refrigerant in the fourth high-pressure pipe 27d in the second high-pressure water heat exchanger 52 and the third high-pressure point H. Since other configurations are the same as those in the first embodiment, description thereof is omitted.

  In the heat pump system 501, for example, the temperature of hot water stored in the hot water storage tank 91 is rising, and the temperature of the hot water detected by the hot water incoming temperature sensor 94T is the second high-pressure water heat. Even when the temperature of the primary refrigerant passing through the outlet of the fourth high-pressure pipe 27d in the exchanger 52 is higher than that of the primary refrigerant toward the third high-pressure point H, the water for hot water supply is not heated. There is no cooling. For this reason, efficient operation is possible even in a situation where the hot water supply load is small.

<5-2> Modified example (A) of the fifth embodiment
As shown in FIG. 8, in the heat pump system 501 of the fifth embodiment, the 55th high-pressure pipe 527e is used instead of the 47th high-pressure pipe 427g while applying the injection path 470 described in the fourth embodiment. The heat pump system 501A may be used.

  In this case, an effect similar to that of the heat pump system 401 of the fourth embodiment can be obtained.

(B)
As shown in FIG. 9, in the heat pump system 501 of the fifth embodiment, the connection destination of the 55th high pressure pipe 527e is changed to the fourth high pressure point while the injection path 70 is deleted as described in the third embodiment. It is good also as the heat pump system 501B made into I.

  In this case, an effect similar to that of the heat pump system 301 of the third embodiment can be obtained.

(C)
As shown in FIG. 10, in the heat pump system 501B of the modification (B) of the fifth embodiment, a heat pump system 501C may be used in which the primary bypass 80 is deleted as described in the second embodiment.

  In this case, an effect similar to that of the heat pump system 201 of the second embodiment can be obtained.

<6-1> Sixth Embodiment As shown in FIG. 11, the heat pump system 601 of the sixth embodiment is a gas-liquid separation injection path 630 in the heat pump system 301 of the third embodiment that does not have the injection path 70. This is a system with The gas-liquid separation injection path 630 includes a pre-separation gas-liquid pipe 631, a gas-liquid separator 632, a post-separation liquid pipe 633, a post-separation air pipe 634, a post-separation tracheal opening / closing valve 635, and a gas-liquid separation expansion valve 605. ing. The pre-separation gas-liquid pipe 631 extends from the third low pressure point M to the gas phase space above the gas-liquid separator 632. The gas-liquid separator 632 separates the primary refrigerant flowing from the pre-separation gas-liquid pipe 631 into a gas phase region in the upper space and a liquid phase region in the lower space. The post-separation liquid pipe 633 guides the primary refrigerant existing in the liquid phase region of the gas-liquid separator 632 to the gas-liquid separation expansion valve 605. In the gas-liquid separation expansion valve 605, the pressure of the passing primary refrigerant is further lowered. The post-separation trachea 634 guides the primary refrigerant existing in the gas phase region of the gas-liquid separator 632 to the injection confluence point D. The post-separation tracheal opening / closing valve 635 can switch between a state where the passage of the primary refrigerant in the post-separation trachea 634 is permitted or a state where it is not permitted. Since other configurations are the same as those in the first embodiment, description thereof is omitted.

  In this heat pump system 601, the decompression of the primary refrigerant in the expansion valve 5a and / or the primary bypass expansion valve 5b is reduced to a pressure lower than the critical pressure equivalent to the primary refrigerant flowing through the intermediate pressure pipe 23, thereby causing a gas-liquid two-phase state. It becomes. Of these, the primary refrigerant in the liquid state is lowered to the pressure of the primary refrigerant flowing through the low pressure pipe 20 in the gas-liquid separation expansion valve 605. Since the post-separation trachea 634 extends from the gas phase region of the gas-liquid separator 632, the liquid primary refrigerant hardly mixes into the post-separation trachea 634, and the gaseous primary refrigerant flows. Thereby, after joining with the primary refrigerant flowing through the intermediate pressure pipe 23 at the injection joining point D, the primary refrigerant sucked by the high-stage compressor 25 is unlikely to become wet. Accordingly, it is possible to prevent liquid compression in the high-stage compressor 25 while increasing efficiency by increasing the density of refrigerant sucked by the high-stage compressor 25. Note that when the primary refrigerant in the expansion valve 5a is depressurized, the pressure is reduced only to the level of the primary refrigerant flowing through the intermediate pressure pipe 23 without being lowered to the pressure of the primary refrigerant flowing through the low pressure pipe 20. For this reason, generation | occurrence | production of the liquid compression of the high stage side compressor 25 which may arise when the temperature of the primary refrigerant | coolant which flows through the after-separation trachea 634 falls too much can be suppressed. Further, even if the temperature of the primary refrigerant passing through the intermediate pressure water heat exchanger 40 is excessively lowered by the secondary refrigerant temperature unified control, the primary refrigerant sucked by the high-stage compressor 25 has a high pressure within a range that does not become wet. The amount of the primary refrigerant going to the water heat exchanger 50 can be increased.

<6-2> Modified example (A) of the sixth embodiment
As shown in FIG. 12, the heat pump system 601 of the sixth embodiment may be a heat pump system 601A that does not have the third high-pressure water heat exchanger 53 as described in the fifth embodiment. Since other configurations are the same as those in the first embodiment, description thereof is omitted.

<7> Seventh Embodiment As shown in FIG. 13, the heat pump system 701 of the seventh embodiment is configured so that the position of the injection confluence point D in the heat pump system 1 of the first embodiment is the discharge side of the low-stage compressor 21. And an injection merging point 7D in the middle of the first intermediate pressure pipe 23a connecting the downstream end of the second intermediate pressure pipe 23b in the intermediate pressure water heat exchanger 40. Since other configurations are the same as those in the first embodiment, description thereof is omitted.

  In this heat pump system 701, for example, the compression ratio of the high stage compressor 25 is increased while the compression ratio of the high stage compressor 25 is increased so that the target temperature is obtained as the discharge refrigerant temperature of the high stage compressor 25. When heating the low-stage compressor 21 at the same compression ratio to increase the driving efficiency, the refrigerant discharged from the low-stage compressor 21 is heated in the intermediate pressure water heat exchanger 40. May become too high for the secondary refrigerant. Even in such a case, it is possible to suppress an excessive increase in the temperature of the secondary refrigerant for heating by providing the injection junction point 7D in the middle of the first intermediate pressure pipe 23a.

  Also in this heat pump system 701, the high-stage compressor after the primary refrigerant passing through the injection path 70 joins at the injection joining point D and after passing through the intermediate pressure water heat exchanger 40 is also shown. The temperature and pressure of the primary refrigerant to be sucked by 25 are values detected by the high-stage suction pressure sensor 24P and the high-stage suction temperature sensor 24T, and the control unit 11 grasps the temperature and pressure of the primary refrigerant. Control which suppresses that the primary refrigerant | coolant to perform will be in a moist state can be performed.

<8> Eighth Embodiment As shown in FIG. 14, the heat pump system 801 of the eighth embodiment changes the order of the economizer heat exchanger 7 and the primary inter-refrigerant heat exchanger 8 in the heat pump system 1 of the first embodiment. It is a reversed system. That is, in the heat pump system 801 of the eighth embodiment, an 83rd intermediate pressure point 8H on the downstream side of the third low pressure point M is provided instead of the third high pressure point H in the heat pump system 1 of the first embodiment. In this system, an injection path 870 is branched from the intermediate pressure point 8H. The 810 high-pressure pipe 827j connects the downstream end of the sixth high-pressure pipe 27f in the third high-pressure water heat exchanger 53 and the fourth high-pressure point I. The 87th high pressure pipe 827g connects the third low pressure point M and the 83rd intermediate pressure point 8H. The 88th high pressure pipe 827h connects the 83rd intermediate pressure point 8H and the upstream end of the 89th high pressure pipe 827i in the economizer heat exchanger 7. Since other configurations are the same as those in the first embodiment, description thereof is omitted.

  In the heat pump system 801, the primary refrigerant heat exchanger 8 can warm the primary refrigerant sucked by the low-stage compressor 21 by the relatively warm primary refrigerant before being cooled by the economizer heat exchanger 7. As a result, even if the temperature of the primary refrigerant passing through the intermediate pressure water heat exchanger 40 is excessively lowered by the secondary refrigerant temperature unified control, the primary refrigerant sucked by the high-stage compressor 25 does not become wet. It becomes possible to increase the amount of the primary refrigerant toward the high-pressure water heat exchanger 50.

<9> Ninth Embodiment As shown in FIG. 15, the heat pump system 901 of the ninth embodiment warms water for hot water supply also in the second high-pressure water heat exchanger 52 in the heat pump system 1 of the first embodiment. This is the system. That is, in the heat pump system 901 of the ninth embodiment, instead of the fourth hot water supply heat pump pipe 95d in the heat pump system 1 of the first embodiment, the 95th upstream connection pipe 995x, the 95th hot water supply heat pump pipe 995d, and the 95th downstream. A connecting pipe 995y is provided, and an upstream connection temperature sensor 95Tx that detects the temperature of hot water passing through the 95th upstream connecting pipe 995x and a temperature of hot water passing through the 95th downstream connecting pipe 995y are detected. This is a system provided with a downstream connection temperature sensor 95Ty. Since other configurations are the same as those in the first embodiment, description thereof is omitted.

  In the heat pump system 901, for example, in the second high-pressure water heat exchanger 52, the secondary refrigerant for heating flowing through the second high-pressure side branch 68b out of the heat released from the fourth high-pressure pipe 27d cannot be absorbed. Since water for hot water flowing through the 95th hot water supply heat pump pipe 995d can be absorbed, heat loss released from the fourth high pressure pipe 27d can be suppressed and used effectively. In addition, since a portion where both the secondary refrigerant for heating and the water for hot water supply receive the heat of the primary refrigerant at the same time is provided, it is necessary to heat the water for hot water supply to the required water temperature. The size of the heat exchanger can be made compact.

<10> Tenth Embodiment A heat pump system 1x according to a tenth embodiment is a system configured to remove the hot water supply circuit 90 in the heat pump system 1 according to the first embodiment, as shown in FIG. That is, the heat pump system 5x of the fourteenth embodiment removes the first high-pressure water heat exchanger 51, the third high-pressure water heat exchanger 53, and the hot water supply circuit 90 in the heat pump system 1 of the first embodiment, and the first high-pressure pipe The 14th upstream high pressure pipe 127a is provided instead of the 27a, the second high pressure pipe 27b, and the third high pressure pipe 27c, and the 14th downstream high pressure pipe is replaced with the fifth high pressure pipe 27e, the sixth high pressure pipe 27f, and the seventh high pressure pipe 27g. 127e is a system provided. The fourteenth upstream high-pressure pipe 127a connects the discharge side of the high-stage compressor 25 and the upstream end of the fourth high-pressure pipe 27d in the second high-pressure water heat exchanger 52. The fourteenth downstream high-pressure pipe 127e connects the downstream end of the fourth high-pressure pipe 27d in the second high-pressure water heat exchanger 52 and the third high-pressure point H. Since other configurations are the same as those in the first embodiment, description thereof is omitted.

  In the heat pump system 5x, even if the hot water supply circuit 90 is not provided, the same effect as that of the first embodiment can be obtained.

<11-1> Eleventh Embodiment As shown in FIG. 17, in the heat pump system 2x of the eleventh embodiment, the water for hot water flowing through the hot water supply circuit 90 in the heat pump system 1 of the first embodiment is also used for heating. In the same manner as the secondary refrigerant, heat is exchanged with the primary refrigerant not only on the high-pressure water heat exchanger 50 side but also on the intermediate-pressure water heat exchanger 40. That is, the heat pump system 2x of the eleventh embodiment includes the second intermediate pressure water heat exchanger 153 that exchanges heat between the primary refrigerant that has passed through the intermediate pressure water heat exchanger 40 and the water for hot water supply. Yes. The second branch hot water supply heat pump pipe 195b extends to the downstream end of the second intermediate pressure water heat exchanger 153 after branching in the middle of the second hot water supply heat pump pipe 95b. In the second intermediate pressure water heat exchanger 153, the hot water supplying water flowing into the third branch hot water supply heat pump pipe 195 c through the second branch hot water supply heat pump pipe 195 b and the third intermediate pressure water heat exchanger 40 after passing through the intermediate pressure water heat exchanger 40 are used. Heat exchange is performed with the primary refrigerant flowing into the eleventh intermediate pressure pipe 123c, which is a part of the intermediate pressure pipe 23c. Water for hot water passing through the third branch hot water supply heat pump pipe 195c in the second intermediate pressure water heat exchanger 153 flows to the branch hot water mixing valve 193 through the fourth branch hot water supply heat pump pipe 195d, and the fourth hot water supply heat pump pipe 95d. It joins with water for hot water that has passed through. The hot-water supply water that has joined at the branch hot-water supply mixing valve 193 flows into the fifth hot-water supply heat pump pipe 95e in the first high-pressure water heat exchanger 51 through the hot-water supply connection pipe 196. Since other configurations are the same as those in the first embodiment, description thereof is omitted.

  In this heat pump system 2x, for example, when the temperature of hot water flowing out from the hot water storage tank 91 toward the heat pump circuit 10 is close to room temperature, which is the temperature of city water, the inside of the intermediate pressure water heat exchanger 40 Even if the primary refrigerant is cooled while passing through the second intermediate pressure pipe 23b, the efficiency may be improved by further cooling in the range where liquid compression does not occur in the high stage compressor 25. In such a case, in the heat pump system 2x of the eleventh embodiment, cold water for hot water supply is compressed not only on the high-pressure water heat exchanger 50 side but also on the downstream side and the high stage side of the intermediate-pressure water heat exchanger 40. The heat of the primary refrigerant flowing between the suction side of the machine 25 can be used for heating.

  By doing in this way, even if it may be a case where the cycle efficiency of the heat pump circuit 10 may be somewhat deteriorated by the above-mentioned secondary refrigerant temperature unified control, the control unit 11 further performs branch hot water mixing. By controlling the valve 193, the flow rate of the fourth branch hot water supply heat pump pipe 195d and the flow rate of the fourth hot water supply heat pump pipe 95d can be adjusted, so that the deterioration of the cycle efficiency of the heat pump circuit 10 can be kept small.

  For example, when the flow efficiency of the intermediate pressure side branch passage 67 of the heating circuit 60 decreases due to the above-described secondary refrigerant temperature unified control, the control unit 11 may use the branch hot water mixing valve when the cycle efficiency of the heat pump circuit 10 is somewhat deteriorated. By controlling 193, the flow rate of the fourth branch hot water supply heat pump pipe 195d can be increased, and the deterioration of the cycle efficiency of the heat pump circuit 10 can be kept small.

<11-2> Modification (A) of the eleventh embodiment
In the heat pump system 2x of the eleventh embodiment, in the intermediate pressure pipe 23 in which the primary refrigerant flows from the low-stage compressor 21 toward the high-stage compressor 25, the heat between the secondary refrigerant for heating. The case where not only the exchange (intermediate pressure water heat exchanger 40) but also the heat exchange (second intermediate pressure water heat exchanger 153) with hot water supply water has been described as an example.

  However, the present invention is not limited to this, and may be a heat pump system capable of heat exchange as described below without departing from the gist of the present invention.

  For example, in the intermediate pressure pipe 23 in which the primary refrigerant flows from the low-stage compressor 21 toward the high-stage compressor 25, the primary refrigerant and the secondary refrigerant for heating in the high-pressure water heat exchanger 50 of the first embodiment. Heat exchange may be performed at three locations, such as heat exchange between water and hot water. Also in this case, similarly to the high-pressure water heat exchanger 50, heat exchange between the hot water supply water and the primary refrigerant flowing through the intermediate pressure pipe 23 is performed by heat exchange between the heating secondary refrigerant and the primary refrigerant. It is preferable that the process is performed separately at two locations of the upstream side and the downstream side.

(B)
In addition, for the hot water supply water, the primary refrigerant flows from the low-stage compressor 21 toward the high-stage compressor 25 without causing heat exchange with the primary refrigerant in the high-pressure water heat exchanger 50. Heat exchange may be performed in the intermediate pressure tube 23.

<12> Twelfth Embodiment A heat pump system 3x according to a twelfth embodiment is a system in which a bypass path is provided in the heating circuit 60 in the heat pump system 1 according to the first embodiment, as shown in FIG. That is, the heat pump system 3x of the twelfth embodiment is a heating circuit 60 in the heat pump system 1 of the first embodiment, in which the heating bypass branch point Z in the middle of the heating return pipe 66 and the heating junction point Y are connected. This is a system in which a bypass passage 69 is further provided and a twelfth heating mixing valve 164 is provided instead of the heating mixing valve 64 in the first embodiment. In the twelfth heating mixing valve 164, the cold heating secondary refrigerant just radiated by the radiator 61 flowing from the heating bypass passage 69 and the heated heating flow flowing through the intermediate pressure side branch passage 67. The mixing ratio of the secondary refrigerant and the warmed secondary refrigerant for heating flowing through the high-pressure side branch 68 is adjusted by an instruction from the control unit 11. Since other configurations are the same as those in the first embodiment, description thereof is omitted.

  In the heat pump system 1 of the first embodiment, even if the heat quantity reduction process is further performed while performing the above-described secondary refrigerant temperature unified control, the heat quantity exceeding the heat quantity required by the radiator 61 is allowed to flow to the radiator 61. May end up. In this way, in the heat pump system 3x of the twelfth embodiment, the control unit 11 operates the twelfth heating mixing valve 164 to open the heating bypass passage 69 even if the amount of heat to the radiator 61 is likely to be excessive. The flow rate of the secondary refrigerant for heating flowing toward the heating junction point Y can be adjusted. Thereby, the secondary refrigerant having a temperature exceeding the temperature required in the radiator 61 and the secondary refrigerant having a temperature lower than the temperature required in the radiator 61 after the heat radiation in the radiator 61 is mixed. Is done. The controller 11 adjusts the mixing ratio in the twelfth heating mixing valve 164 so that the temperature of the secondary refrigerant after mixing becomes the temperature required in the radiator 61.

  Accordingly, the secondary refrigerant having the temperature required in the radiator 61 can be supplied to the radiator 61 while suppressing the occurrence of liquid compression in the high-stage compressor 25.

<13> Thirteenth Embodiment As shown in FIG. 19, the heat pump system 4x of the thirteenth embodiment is the same as the heat pump system 1 of the first embodiment except that the economizer heat exchanger 7 and the third high pressure point H are the third low pressure. This is a system configured to be sandwiched between a point and a portion branched by a flow toward the primary inter-refrigerant heat exchanger 8 and a flow toward the primary bypass 80. That is, in the heat pump system 4x of the thirteenth embodiment, the fourth high pressure point I in the heat pump system 1 of the first embodiment is changed, and is upstream of the third high pressure point H and from the third high pressure water heat exchanger 53. Is a system including the thirteenth primary bypass 80x and the thirteenth injection path 70x, which is the thirteenth high pressure point 13I on the downstream side. The seventh high pressure pipe 127g connects the downstream end of the sixth high pressure pipe 27f in the third high pressure water heat exchanger 53 and the thirteenth high pressure point 13I. The bypass upstream economizer high pressure pipe 127n connects the thirteenth high pressure point 13I and the third high pressure point H. The bypass downstream economizer high-pressure pipe 127j connects between the downstream end of the ninth high-pressure pipe 27i in the economizer heat exchanger 7 and the primary bypass expansion valve 5b. Since other configurations are the same as those in the first embodiment, description thereof is omitted.

  In this heat pump system 3x, for example, the primary refrigerant that is directed to the expansion valve 5a is divided into a flow path that is cooled by the economizer heat exchanger 7 and a flow path that is cooled by the heat exchanger 8 between the primary refrigerants. It becomes possible to adjust how much the primary refrigerant is cooled.

<14> Modifications applicable to each of the above embodiments In the first to thirteenth embodiments, each heat pump system has been specifically described. However, the present invention is not limited to this, and the present invention includes those in which the heat pump system of each embodiment is configured as described below without departing from the scope of the invention.

<14-1>
In each of the above embodiments, the case where carbon dioxide is used as the primary refrigerant has been described as an example.

  However, in any of the above embodiments, ethylene, ethane, nitrogen oxide, or the like, which is a refrigerant other than carbon dioxide, may be employed as the primary refrigerant. In this case, it is preferable that the refrigerant employed is a refrigerant in which the discharge refrigerant pressure of the high-stage compressor 25 is used exceeding the extreme pressure and the driving force of each compressor can be kept small.

<14-2>
In each said embodiment, in the heating circuit 60, the case where the water as a secondary refrigerant circulates was mentioned as an example, and was demonstrated.

  However, in any of the above embodiments, the secondary refrigerant is not limited to water, and brine or the like may be used as another heat medium.

<14-3>
In each of the above embodiments, the case where the low-stage compressor 21 and the high-stage compressor 25 are provided is described as an example.

  However, in any of the above-described embodiments, a so-called single-shaft double-stage or single-shaft multi-stage type compression mechanism in which a common drive shaft is employed in the low-stage compressor 21 and the high-stage compressor 25 is provided. It may be done. In this case, it is possible to increase driving efficiency by providing a phase difference of 180 degrees in each compression mechanism.

<14-4>
In each of the above embodiments, the case where the low-stage compressor 21 and the high-stage compressor 25 are connected in series has been described as an example.

  However, in any of the above embodiments, a form in which three or more compression mechanisms are connected in series may be used. In that case, heat load processing may be performed using the heat of the primary refrigerant flowing between the compression mechanisms. In addition, as long as two or more series connection circuits are provided in the compression mechanism, another compression mechanism may be provided in parallel or in series.

<14-5>
In each of the above embodiments, an example is given of a case where the temperature of the secondary refrigerant flowing through the intermediate pressure side branch 67 and the high pressure side branch 68 of the heating circuit 60 is controlled to coincide with the temperature required in the radiator 61. explained.

  However, in any of the above embodiments, the optimization of the cycle efficiency in the heat pump circuit 10 may be absolutely prioritized over the supply of the heat amount required in the radiator 61. In this case, in order to maintain the cycle efficiency of the heat pump circuit 10 satisfactorily, the supply of heat to the radiator 61 may be insufficient. In this case, as shown in FIG. 20, the heating that passes between the downstream side including the third high-pressure side branch path 68 c of the heating circuit 60 or the downstream side including the third intermediate-pressure side branch path 67 c to the radiator 61. It is good also as the heat pump system 5x provided with 60 A of external heat-source parts for heating the secondary refrigerant | coolant for use. In this case, a change in the environment in which the evaporator 4 is installed, a change in the heating load, or a change in the hot water supply load occurs, so that the cycle efficiency of the heat pump circuit 10 can be maintained satisfactorily so that the heating load cannot be handled. Even when this occurs, it becomes possible to cope with the heating load while maintaining the cycle efficiency of the heat pump circuit 10 well. A heat supply unit similar to the external heat source unit 60 </ b> A may be provided only in the hot water supply circuit 90, or may be provided in both the heating circuit 60 and the hot water supply circuit 90.

  Moreover, in order to maintain the cycle efficiency of the heat pump circuit 10 satisfactorily, there may be a case where the amount of heat supplied to the radiator 61 becomes excessive. In this case, as shown in FIG. 21, the heating that passes between the downstream side including the third high-pressure side branch path 68 c of the heating circuit 60 or the downstream side including the third intermediate-pressure side branch path 67 c to the radiator 61. It is good also as the heat pump system 6x provided with the external cooling source part 60B for cooling the secondary refrigerant | coolant for this. As this external cooling source part 60B, for example, a part of the water supply pipe 94 through which the external room temperature city water flows is bypassed by the water supply branch valve 94B and the water supply branch 194, so The secondary refrigerant flowing in the heating forward pipe 65 may be cooled by exchanging heat with the heating secondary refrigerant flowing in the pipe 65. In this case, a change in the environment in which the evaporator 4 is installed, a change in the heating load, or a change in the hot water supply load occurs, so that the cycle efficiency of the heat pump circuit 10 can be maintained satisfactorily so that the heating load cannot be handled. Even when this occurs, it becomes possible to cope with the heating load while maintaining the cycle efficiency of the heat pump circuit 10 well. In addition, when the feed water branch valve 94B is used, the heat pump system 10 increases the efficiency of the heat pump system by recovering the heat supplied by the heat pump circuit 10 to the secondary refrigerant of the heating circuit 60 as heat for water supply. You can also. The heat supply unit similar to the external cooling source unit 60B may be provided only in the hot water supply circuit 90, or may be provided in both the heating circuit 60 and the hot water supply circuit 90.

<14-6>
In each of the above embodiments, the temperature required for the radiator 61 of the heating circuit 60, the temperature required for hot water flowing through the sixth hot water supply heat pump pipe 95f flowing into the hot water storage tank 91 in the hot water supply circuit 90, and the heat pump circuit The case where the relationship with the temperature of the primary refrigerant flowing through the 10 intermediate-pressure water heat exchangers 40 and the high-pressure water heat exchanger 50 is not particularly limited has been described as an example.

  However, in any of the above-described embodiments, the control unit 11 controls the expansion valve 5a so that the temperature of the primary refrigerant flowing through the intermediate pressure water heat exchanger 40 exceeds the temperature required by the radiator 61 of the heating circuit 60. The cycle efficiency of the heat pump circuit 10 is improved under the condition that the valve opening, the drive frequency of the low-stage compressor 21, the drive frequency of the high-stage compressor 25, etc. are controlled. May be. In this case, the heating circuit 60 produces a secondary refrigerant having a temperature required in the radiator 61 only by the heat obtained by the secondary refrigerant flowing on the intermediate pressure side branch passage 67 side which is the intermediate pressure water heat exchanger 40 side. It becomes possible.

<14-7>
In each of the above embodiments, the case where the compression ratio of the low-stage compressor 21 and the compression ratio of the high-stage compressor 25 are made equal in order to increase the cycle efficiency of the heat pump circuit 10 has been described as an example.

  However, in any of the above embodiments, the compression ratio of the low-stage compressor 21 and the compression ratio of the high-stage compressor 25 are not necessarily the same. For example, the difference between the two compression ratios is reduced. Such control is also included.

<14-8>
For example, in performing the secondary refrigerant temperature unified control described in the above embodiment, the control unit 11 increases the flow rate of the heating pump 63 when the unified temperature exceeds the temperature required by the radiator 61. The heat exchange time may be shortened. However, if control is performed to increase the flow rate of the heating pump 63 in this way, the primary refrigerant in the intermediate-pressure water heat exchanger 40 is further cooled, and thus the primary suctioned by the high-stage compressor 25. There is a possibility that the degree of superheat of the refrigerant may be reduced or become damp.

  In such a case, for example, the control unit 11 does not change the target discharge temperature of the low-stage compressor 21 and does not change the target discharge temperature of the high-stage compressor 25. The low-stage suction superheat degree control for increasing the superheat degree of the primary refrigerant sucked by the machine 21 may be performed.

  For example, assume that the cycle of the heat pump circuit 10 is executed and the flow rate of the heating pump 63 is increased, as indicated by the dotted line in the Mollier diagram of FIG. Here, the control unit 11 performs low-stage suction superheat degree control, so that the target discharge temperature of the high-stage compressor 25 is not changed without changing the target discharge temperature of the low-stage compressor 21. The degree of superheat of the primary refrigerant sucked by the low stage compressor 21 is increased. As a result, the cycle of the heat pump circuit 10 is executed as indicated by the solid line in the Mollier diagram of FIG. Here, in the Mollier diagram of FIG. 22, when the high-stage compressor 25 sucks the primary refrigerant, when comparing the dotted line cycle and the solid line cycle, the solid line cycle is farther from the saturated vapor line. It is moving in the direction and the degree of superheat is increasing. As a result, although the suction refrigerant density of the low-stage compressor 21 is somewhat reduced, the degree of superheat of the primary refrigerant sucked by the high-stage compressor 25 is reduced due to changes in ambient conditions such as an increase in heating load. Even so, the state of the primary refrigerant sucked by the high-stage compressor 25 is in a state where the degree of superheat is increased by moving in a direction away from the saturated vapor line. For this reason, liquid compression is unlikely to occur in the high-stage compressor 25. Further, even when the cycle indicated by the solid line in the Mollier diagram of FIG. 22 is performed as described above, the target discharge temperature of the low-stage compressor 21 and the target discharge temperature of the high-stage compressor 25 are not changed. . For this reason, heating of the secondary refrigerant for heating by heat exchange in the intermediate-pressure water heat exchanger 40 and heating of the secondary refrigerant for heating by heat exchange in the high-pressure water heat exchanger 50 are sufficiently performed. Is done. Moreover, since both the compression ratio of the low stage side compressor 21 and the compression ratio of the high stage side compressor 25 can be made small, the efficiency of the heat pump circuit 10 can also be improved.

  The above-described low-stage suction superheat degree control is performed, for example, in the heat pump circuit 10 having the primary bypass 80 and the primary bypass expansion valve 5b in the heat pump system shown in the embodiment and the modified example. The degree of heat exchange in the primary refrigerant heat exchanger 8 can be adjusted by the control unit 11 controlling the valve opening degree of the bypass expansion valve 5b. In this way, the degree of superheat of the primary refrigerant sucked by the low-stage compressor 21 can be adjusted.

<14-9>
In the above embodiments, the case where the target discharge temperature of the low stage compressor 21 and the target discharge temperature of the high stage compressor 25 are the same has been described as an example.

  However, in any of the above embodiments, the control unit 11 drives the low-stage compressor 21 so that the target discharge temperature of the low-stage compressor 21 and the target discharge temperature of the high-stage compressor 25 are different. You may make it control a frequency, the drive frequency of the high stage side compressor 25, the valve opening degree of the expansion valve 5a, etc. FIG. In this case, low-stage discharge temperature lowering control may be performed to lower the target discharge temperature of the low-stage compressor 21.

  For example, assume that the cycle of the heat pump circuit 10 is executed and the flow rate of the heating pump 63 is increased, as indicated by the dotted line in the Mollier diagram of FIG. Here, the control unit 11 performs the low stage discharge temperature lowering control, thereby lowering the target discharge temperature of the low stage side compressor 21 and changing the target discharge temperature of the high stage side compressor 25 without changing the target discharge temperature. The flow rate of the secondary refrigerant for heating flowing in the second high-pressure water heat exchanger 52 is increased while the flow rate of the secondary refrigerant for heating flowing in the pressure water heat exchanger 40 is lowered. Here, the target discharge temperature of the low-stage compressor 21 is set to, for example, 65 ° C. so as not to be lower than the temperature required in the radiator 61 of the heating circuit 60. As a result, the cycle of the heat pump circuit 10 is executed as indicated by the solid line in the Mollier diagram of FIG. Here, in the Mollier diagram of FIG. 23, when the high-stage compressor 25 sucks the primary refrigerant, the dotted cycle and the solid cycle are compared, and the solid cycle is farther from the saturated vapor line. It is moving in the direction and the degree of superheat is increasing. Thereby, even if the flow rate of the heating pump 63 is increased and the degree of superheat of the primary refrigerant sucked by the high-stage compressor 25 may be reduced, the primary refrigerant sucked by the high-stage compressor 25 is reduced. Since the state is that the degree of superheat is increased by moving in a direction away from the saturated vapor line, liquid compression is unlikely to occur in the high-stage compressor 25. Further, even when the cycle indicated by the solid line in the Mollier diagram of FIG. 23 is performed as described above, the target discharge temperature of the high stage compressor 25 is not changed. Moreover, although the target discharge temperature of the low stage side compressor 21 is lowered, the flow rate of the secondary refrigerant for heating passing through the intermediate pressure water heat exchanger 40 is also lowered, so that it corresponds to the load. You can maintain a situation that you can do. Moreover, since both the compression ratio of the low stage side compressor 21 and the compression ratio of the high stage side compressor 25 can be made small, the efficiency of the heat pump circuit 10 can also be improved.

  In the above-described low-stage discharge temperature decrease control, for example, the control unit 11 controls the valve opening degree of the expansion valve 5a, the drive frequency of the low-stage compressor 21, the drive frequency of the high-stage compressor 25, and the like. This can be achieved.

<14-10>
In each of the above embodiments, the case where the ambient temperature environment condition of the radiator 61 in which the heat pump system is used is not particularly limited has been described as an example.

  However, in any of the above embodiments, the temperature of the secondary refrigerant radiated by the radiator 61 is a temperature range condition between the critical temperature of carbon dioxide as the primary refrigerant and a temperature about 5 degrees lower than the critical temperature. This condition may be limited as a use environment condition of the heat pump system.

  When the heat pump system is used in such a use environment, the heat pump system is used for a heat load having a temperature lower than the critical temperature of carbon dioxide as a primary refrigerant. For this reason, heat exchange can be performed in the high-pressure water heat exchanger 50 between the primary refrigerant in a state exceeding the critical pressure and the secondary refrigerant having a temperature lower than the critical temperature. Heat dissipation treatment can be performed in an area where the slope of the isotherm is gentle. For this reason, the driving | operation which increased the enthalpy difference between the start of the thermal radiation process of a primary refrigerant | coolant and the completion | finish of a thermal radiation process can be performed.

<14-11>
In each of the above embodiments, the control unit 11 controls the flow rate of the heating mixing valve 64 and the heating pump 63 based on the temperatures detected by the intermediate pressure side branch temperature sensor 67T and the high pressure side branch temperature sensor 68T, and the heating circuit 60 The system in which the flow rate of the secondary refrigerant in the third intermediate pressure side branch path 67c and the third high pressure side branch path 68c may not be grasped has been described as an example.

  However, in any of the above embodiments, as shown in FIG. 24, instead of the intermediate pressure side branch temperature sensor 67T and the high pressure side branch temperature sensor 68T, the secondary refrigerant for heating flowing through the intermediate pressure side branch 67 The heat pump system 7x may include an intermediate pressure side branch flow meter 67Q that grasps the flow rate and a high pressure side branch flow meter 68Q that grasps the flow rate of the secondary refrigerant for heating that flows through the high pressure side branch 68. .

  In the heat pump system 7x, the control unit 11 uses the flow rate grasped by the intermediate pressure side branch flow meter 67Q and the flow rate grasped by the high pressure side branch flow meter 68Q for heating through the third intermediate pressure side branch flow channel 67c. The flow rate of the heating mixing valve 64 and / or the heating pump 63 is controlled so that the difference between the temperature of the secondary refrigerant and the temperature of the secondary refrigerant for heating flowing through the third high-pressure side branch 68c is reduced. In addition, the temperature of the secondary refrigerant for heating flowing through the third intermediate pressure side branch path 67c and the temperature of the secondary refrigerant for heating flowing through the third high pressure side branch path 68c are the same temperature. May be controlled.

  The control unit 11 grasps the temperature of the primary refrigerant flowing through the intermediate pressure water heat exchanger 40 with the intermediate pressure temperature sensor 23T, and drives the flow rate of the primary refrigerant flowing through the intermediate pressure water heat exchanger 40 to the low-stage compressor 21. The frequency, the detected temperature of the intermediate pressure temperature sensor 23T, and the detected pressure of the high stage suction pressure sensor 24P are grasped. Moreover, the control part 11 grasps | ascertains the temperature of the secondary refrigerant | coolant for heating which passes the 1st intermediate pressure side branch path 67a with the temperature which the heating return temperature sensor 66T detects. The control unit 11 further grasps the flow rate of the secondary refrigerant flowing through the intermediate pressure side branch passage 67 by the intermediate pressure side branch passage flow meter 67Q. Thus, the control unit 11 calculates the amount of heat obtained by the heating secondary refrigerant based on the temperature difference between the primary refrigerant and the heating secondary refrigerant in the intermediate-pressure water heat exchanger 40 and each flow rate, and The expected value is calculated as the temperature of the secondary refrigerant for heating that passes through the third intermediate pressure side branch passage 67c.

  The control unit 11 controls the second high pressure water heat exchanger 52 based on the driving frequency of the high pressure sensor 27T, the high pressure sensor 27P and the high stage compressor 25, the flow rate of the hot water supply intermediate temperature sensor 95T and the hot water supply pump 92, and the like. Know the temperature and flow rate of the flowing primary refrigerant. Moreover, the control part 11 grasps | ascertains the temperature of the secondary refrigerant | coolant for heating which passes the 1st high voltage | pressure side branch 68a by the temperature which the heating return temperature sensor 66T detects. Further, the control unit 11 grasps the flow rate of the secondary refrigerant flowing through the high-pressure side branch 68 using the high-pressure side branch flow meter 68Q. Thereby, the control part 11 calculates the calorie | heat amount which the secondary refrigerant | coolant for heating obtains based on the temperature difference and each flow volume of the primary refrigerant | coolant in the 2nd high pressure water heat exchanger 52, and the secondary refrigerant | coolant for heating, An expected value is calculated as the temperature of the secondary refrigerant for heating passing through the third high-pressure side branch path 68c.

  The controller 11 calculates the temperature of the secondary refrigerant for heating that passes through the third intermediate pressure side branch 67c calculated as described above and the secondary refrigerant for heating that passes through the third high pressure side branch 68c. The heating mixing valve 64 and / or the heating pump 63 is controlled so that the difference from the temperature becomes small. The temperature of the secondary refrigerant for heating that passes through the third intermediate pressure side branch passage 67c calculated here and the temperature of the secondary refrigerant for heating that passes through the third high pressure side branch passage 68c are used. The content of the general control is the same as the content described in the above embodiment.

  In this way, even in the heat pump system 7x in which the intermediate pressure side branch path temperature sensor 67T and the high pressure side branch path temperature sensor 68T are not provided, the secondary refrigerant for heating that passes through the third intermediate pressure side branch path 67c. The difference between the temperature and the temperature of the secondary refrigerant for heating that passes through the third high-pressure side branch 68c can be reduced.

<14-12>
As shown in FIG. 25, instead of providing the high-pressure side branch flow meter 68Q as described in the modification <14-11>, a heat pump system 8x provided with the forward pipe flow meter 65Q may be used.

  The forward pipe flow meter 65Q can grasp the flow rate of the secondary refrigerant for heating that passes through the heating forward pipe 65. Also by the intermediate pressure side branch flow meter 67Q and the forward pipe flow meter 65Q, the flow rate of the intermediate pressure side branch flow meter 67Q is subtracted from the flow rate of the heating forward pipe 65 that can be grasped from the forward flow meter 65Q. The flow rate of the secondary refrigerant for heating flowing through the side branch 68 can be grasped. Other control methods and calculation methods can be the same as those of the modified example <14-11>.

  Further, the forward pipe flow meter 65Q may be provided instead of providing the low pressure side branch flow meter 67Q instead of replacing the high pressure side branch flow meter 68Q.

<14-13>
In addition, as shown in FIG. 26, it is good also as the heat pump system 9x which provided the outgoing pipe temperature sensor 65T instead of the high voltage | pressure side branch path temperature sensor 68T demonstrated in said each embodiment.

  The forward pipe temperature sensor 65T can grasp the temperature of the secondary refrigerant for heating that passes through the heating forward pipe 65. The intermediate pressure side branch path temperature sensor 67T and the forward pipe temperature sensor 65T also calculate the amount of heat of the secondary refrigerant for heating flowing through the heating forward pipe 65 from the temperature of the heating forward pipe 65 that can be grasped from the forward pipe temperature sensor 65T. Then, by subtracting the amount of heat of the secondary refrigerant for heating flowing through the intermediate pressure side branch path 67 obtained from the temperature grasped by the intermediate pressure side branch path temperature sensor 67T, the secondary refrigerant for heating flowing through the high pressure side branch path 68 The amount of heat can be grasped. When the flow rate of the secondary refrigerant for heating that flows through the high-pressure side branch 68 can be grasped, the amount of heat of the secondary refrigerant for heating that flows through the high-pressure side branch 68 that is grasped in this manner is used. The temperature of the secondary refrigerant flowing through the branch path 68 can be grasped. As described above, the control after the temperature of the secondary refrigerant for heating flowing through the intermediate pressure side branch path 67 and the temperature of the secondary refrigerant for heating flowing through the high pressure side branch path 68 are as described above. It can be made to be the same as that explained in.

  Further, the forward pipe temperature sensor 65T may be provided instead of providing the low pressure side branch temperature sensor 67T instead of replacing the high pressure side branch temperature sensor 68T.

  As described above, when the forward pipe temperature sensor 65T is provided, the control unit 11 detects the temperature of the secondary refrigerant for heating detected by the forward pipe temperature sensor 65T and other temperature sensors (for example, The heating mixing valve 64 and the heating pump 63 may be controlled so that the difference between the temperature of the secondary refrigerant for heating grasped by the intermediate pressure side branch path temperature sensor 67T) is reduced. Even in this case, the same effects as those of the above embodiments can be obtained.

<14-14>
In each of the above embodiments, the case where the temperatures of the secondary refrigerants flowing through the third intermediate pressure side branch path 67c and the third high pressure side branch path 68c are unified in the secondary refrigerant temperature unified control has been described as an example.

  However, in any of the above embodiments, the present invention is not limited to the case where the temperature is completely the same, but simply the temperature of the secondary refrigerant flowing through the third intermediate pressure side branch path 67c and the third high pressure side branch. The control may be such that the difference between the temperature of the secondary refrigerant flowing in the path 68c and the temperature of the secondary refrigerant is reduced.

  Furthermore, the difference between the temperature of the secondary refrigerant flowing through the third intermediate pressure side branch path 67c and the temperature of the secondary refrigerant flowing through the third high pressure side branch path 68c is not reduced, but the difference is less than a predetermined value. Control may be performed so as to satisfy the condition.

<14-15>
In each of the above embodiments, the case where the flow rate ratio in the heating and mixing valve 64 is controlled when performing the secondary refrigerant temperature unified control has been described as an example.

  However, in any of the above embodiments, the temperature of the secondary refrigerant for heating that flows through the third intermediate pressure side branch 67c and the temperature for heating that flows through the third high pressure side branch 68c by controlling the flow rate ratio in the heating mixing valve 64. The control is not limited to reducing the difference from the temperature of the secondary refrigerant. For example, the control unit 11 controls the third intermediate pressure side branch passage 67c by increasing the flow rate of the heating pump 63 or decreasing the flow rate of the heating pump 63. The present invention also includes a case where the difference between the temperature of the flowing secondary refrigerant for heating and the temperature of the secondary refrigerant for heating flowing in the third high-pressure side branch 68c is reduced.

  For example, in the case where the temperature of the secondary refrigerant flowing through the third high pressure side branch 68c is lower than the temperature of the secondary refrigerant flowing through the third intermediate pressure side branch 67c, heat exchange is performed in the second high pressure water heat exchanger 52. In a situation where the temperature difference between the primary refrigerant that performs heating and the secondary refrigerant for heating is greater than the temperature difference between the primary refrigerant that performs heat exchange in the intermediate pressure water heat exchanger 40 and the secondary refrigerant for heating, It is also possible to reduce the temperature difference by controlling the flow rate of the heating pump 63 by the unit 11. In this case, reducing the flow rate of the heating pump 63 increases the time for receiving heat from the primary refrigerant in any of the heat exchangers. This is because the secondary refrigerant for heating passes through the second high-pressure water heat exchanger 52 side having a large temperature difference from the secondary refrigerant.

  Further, when the temperature of the secondary refrigerant flowing through the third high-pressure side branch 68c is higher than the temperature of the secondary refrigerant flowing through the third intermediate-pressure side branch 67c, heat exchange is performed in the second high-pressure water heat exchanger 52. In a situation where the temperature difference between the primary refrigerant that performs heating and the secondary refrigerant for heating is larger than the temperature difference between the primary refrigerant that performs heat exchange in the intermediate pressure water heat exchanger 40 and the secondary refrigerant for heating, It is also possible to reduce the temperature difference by performing the control in which the unit 11 increases the flow rate of the heating pump 63. In this case, by increasing the flow rate of the heating pump 63, the time for receiving heat from the primary refrigerant in any heat exchanger is shortened. This is because the secondary refrigerant for heating passes through the second high-pressure water heat exchanger 52 side having a large temperature difference from the secondary refrigerant.

  Further, when the temperature of the secondary refrigerant flowing through the third high-pressure side branch 68c is lower than the temperature of the secondary refrigerant flowing through the third intermediate-pressure side branch 67c, heat exchange is performed in the second high-pressure water heat exchanger 52. In a situation where the temperature difference between the primary refrigerant that performs heating and the secondary refrigerant for heating is smaller than the temperature difference between the primary refrigerant that performs heat exchange in the intermediate pressure water heat exchanger 40 and the secondary refrigerant for heating, It is also possible to reduce the temperature difference by the control that the unit 11 increases the flow rate of the heating pump 63. In this case, by increasing the flow rate of the heating pump 63, the time for receiving heat from the primary refrigerant in any heat exchanger is shortened. This is because the secondary refrigerant for heating passes through the intermediate pressure water heat exchanger 40 side having a large temperature difference from the secondary refrigerant.

  Further, when the temperature of the secondary refrigerant flowing through the third high-pressure side branch 68c is higher than the temperature of the secondary refrigerant flowing through the third intermediate-pressure side branch 67c, heat exchange is performed in the second high-pressure water heat exchanger 52. In a situation where the temperature difference between the primary refrigerant that performs heating and the secondary refrigerant for heating is smaller than the temperature difference between the primary refrigerant that performs heat exchange in the intermediate pressure water heat exchanger 40 and the secondary refrigerant for heating, It is also possible to reduce the temperature difference by controlling the flow rate of the heating pump 63 by the unit 11. In this case, reducing the flow rate of the heating pump 63 increases the time for receiving heat from the primary refrigerant in any of the heat exchangers. This is because the secondary refrigerant for heating passes through the intermediate pressure water heat exchanger 40 side having a large temperature difference from the secondary refrigerant.

<14-16>
In each of the above embodiments, the relationship between the temperature of the primary refrigerant flowing through the intermediate-pressure water heat exchanger 40 and the temperature of the primary refrigerant flowing through the second high-pressure water heat exchanger 52 is taken as an example when no control is performed. I gave it as an explanation.

  However, in any of the above embodiments, for example, the temperature of the primary refrigerant flowing into the second high-pressure water heat exchanger 52 is adjusted by adjusting the flow rate of hot water passing through the first high-pressure water heat exchanger 51. And the controller 11 may control the hot water supply pump 92 so as to approach the temperature of the primary refrigerant flowing into the intermediate pressure water heat exchanger 40.

  For example, when the target discharge temperature of the high stage side compressor 25 is set higher than the target discharge temperature of the low stage side compressor 21, the temperature of the primary refrigerant discharged from the high stage side compressor 25 is set. If not lowered, the inlet temperature of the primary refrigerant of the intermediate-pressure water heat exchanger 40 and the inlet temperature of the primary refrigerant of the second high-pressure water heat exchanger 52 cannot be brought close to each other. In such a case, the hot water supply water necessary for the control unit 11 to cool the primary refrigerant in the first high pressure water heat exchanger 51 is supplied based on the temperature detected by the hot water supply intermediate temperature sensor 95T. Alternatively, the hot water supply pump 92 may be controlled.

  In this case, the temperature in the vicinity of the inlet of the primary refrigerant of the intermediate pressure water heat exchanger 40 corresponding to the outlet side of the secondary refrigerant for heating and the second high-pressure water heat corresponding to the outlet of the secondary refrigerant for heating. Since the temperature in the vicinity of the inlet of the primary refrigerant in the exchanger 52 is a close value, the temperature of the secondary refrigerant for heating that flows through the third intermediate pressure side branch 67c and the temperature for heating that flows through the third high pressure side branch 68c. It becomes easy to make the temperature of the secondary refrigerant close. For example, when the flow rate of the heating pump 63 is lowered, it is easier to unify the temperatures. Further, it becomes easy to bring the temperature of the secondary refrigerant for heating flowing through the third intermediate pressure side branch passage 67c close to the temperature of the secondary refrigerant for heating flowing through the third high pressure side branch passage 68c. The degree of deterioration of the cycle efficiency in the heat pump circuit 10 caused by the unified refrigerant temperature control can be kept small.

<14-17>
In each of the above-described embodiments, the case where the control on the heat pump circuit 10 side is not clearly described has been described as an example.

  However, although the operation state changes by performing the secondary refrigerant temperature unified control in the heating circuit 60, the deterioration of the cycle efficiency of the heat pump circuit 10 may be suppressed or may be improved.

  Here, for example, as shown in the Mollier diagram of FIG. 27, when the target discharge temperature of the low-stage compressor 21 is increased in order to cope with the heating load, in the low-stage compressor 21 The compression ratio tends to increase (see change from dotted line to dashed line). Along with this, the compression ratio of the high-stage compressor 25 that attempts to make the compression ratio uniform also increases. For this reason, the required driving force increases and the energy consumption increases.

  On the other hand, for example, as shown in the Mollier diagram of FIG. 28, the control unit 11 may change the operation state from a dotted line cycle to a solid line cycle (see change from a dotted line to a solid line). . That is, when the target discharge temperature of the low-stage compressor 21 is increased, the low-stage intake superheat control is performed so that the superheat degree of the primary refrigerant sucked by the low-stage compressor 21 is increased. Good. Thereby, the compression ratio of the low stage side compressor 21 required in order to achieve the target discharge temperature of the low stage side compressor 21 can be suppressed small. Accompanying this, the compression ratio of the high-stage compressor 25 can also be kept small. As a result, the required driving force can be further reduced.

  On the other hand, when the cycle state is changed so that the target discharge temperature of the low-stage compressor 21 can be lowered, the low-stage intake superheat that reduces the superheat degree of the primary refrigerant sucked by the low-stage compressor 21 is reduced. You may make it perform degree control. Thereby, by suppressing the increase in the compression ratio of the low-stage compressor 21, the increase in the compression ratio of the high-stage compressor 25 is also suppressed, and the specific volume of the primary refrigerant sucked by the low-stage compressor 21 is reduced. Can do. For this reason, it is possible to increase the capacity by securing the circulation amount while suppressing the increase in the compression ratio.

  In the heat pump circuit 10 having the primary bypass 80 and the primary bypass expansion valve 5b in the heat pump system shown in the embodiment and the modified example, for example, the above-described control is performed by the primary bypass expansion valve 5b. The degree of heat exchange in the primary refrigerant heat exchanger 8 can be adjusted by the control unit 11 controlling the valve opening. In this way, the degree of superheat of the primary refrigerant sucked by the low-stage compressor 21 can be adjusted.

<14-18>
In each of the above-described embodiments, the case where the control on the heat pump circuit 10 side is not clearly described has been described as an example.

  However, although the operation state changes by performing the secondary refrigerant temperature unified control in the heating circuit 60, the deterioration of the cycle efficiency of the heat pump circuit 10 may be suppressed or may be improved.

  Here, for example, when the temperature of the secondary refrigerant for heating does not decrease so much in the radiator 61 due to a reduction in heating load or the like, a high temperature is required as the temperature of the primary refrigerant flowing through the intermediate pressure water heat exchanger 40. It may not be.

  On the other hand, for example, as shown in the Mollier diagram of FIG. 29, the control unit 11 may change the operation state from a dotted line cycle to a solid line cycle (see change from a dotted line to a solid line). . That is, the control may be performed so that the degree of superheat of the primary refrigerant sucked by the low-stage compressor 21 is also lowered while the target discharge temperature of the low-stage compressor 21 is lowered. As a result, the compression ratio of the high-stage compressor 25 and the compression ratio of the low-stage compressor 21 are approximately the same, and the driving force of the low-pressure compressor 21 and the high-stage compressor 25 is suppressed to be small. Driving becomes possible. And even if the target discharge temperature of the low stage side compressor 21 is lowered in this way, since the thermal load required in the radiator 61 is small, it is possible to cope with the load. As a result, the compression driving force can be further reduced while accommodating load fluctuations.

  In the heat pump circuit 10 having the primary bypass 80 and the primary bypass expansion valve 5b in the heat pump system shown in the embodiment and the modified example, for example, the above-described control is performed by the primary bypass expansion valve 5b. The degree of heat exchange in the primary refrigerant heat exchanger 8 can be adjusted by the control unit 11 controlling the valve opening. In this way, the degree of superheat of the primary refrigerant sucked by the low-stage compressor 21 can be adjusted.

  Since the refrigeration apparatus of the present invention can improve cycle efficiency in the processing of heat load by the secondary refrigerant, the heat pump system is used to process the heat load using a heat pump circuit including a multistage compression type compression element. It is particularly useful when applied to.

DESCRIPTION OF SYMBOLS 1 Heat pump system 4 Evaporator 4f Fan 5a Expansion valve 5b Primary bypass expansion valve 7 Economizer heat exchanger 8 Heat exchanger between primary refrigerants 10 Heat pump circuit 20 Low pressure pipe 20a-f First to sixth low pressure pipes 20P Low pressure sensor 20T Low pressure temperature Sensor 21 Low stage compressor 23 Intermediate pressure pipes 23a to d First to fourth intermediate pressure pipes 23T Intermediate pressure temperature sensor 24P High stage suction pressure sensor 24T High stage suction temperature sensor 25 High stage compressor 27 High pressure pipes 27a to n First -14 high pressure pipe 27P high pressure sensor 27T high pressure temperature sensor 40 intermediate pressure water heat exchanger 50 high pressure water heat exchanger 51-53 first to third high pressure water heat exchanger 60 heating circuit 61 radiator 61T radiator temperature sensor 62 shunt mechanism ( First flow rate adjustment mechanism)
63 Heating pump (flow control part)
64 Heating mixing valve 65 Heating forward pipe 65T Outward pipe temperature sensor 65Q Outward pipe flow meter 66 Heating return pipe 66T Heating return temperature sensor 67 Intermediate pressure side branch path 67T Intermediate pressure side branch path temperature sensor 67Q Intermediate pressure side branch path flow meter 67a-c 1-3 intermediate pressure side branch 68 high pressure side branch 68T high pressure side branch temperature sensor 68Q high pressure side branch flow meter 69 heating bypass (first thermal load bypass)
DESCRIPTION OF SYMBOLS 70 Injection path 72 1st injection pipe 74 2nd injection pipe 75 3rd injection pipe 76 4th injection pipe 73 Injection expansion valve 80 Primary bypass 90 Hot water supply circuit 91 Hot water storage tank 92 Hot water pump 93 Hot water mixing valve 94 Water supply pipe 94T Hot water supply water temperature Sensor 95 Hot water supply heat pump pipe 95a-f First to sixth hot water supply heat pump pipes 95T Hot water supply intermediate temperature sensor 98 Hot water supply pipe 98T Hot water supply hot water temperature sensor 99 Hot water supply bypass pipe 164 12th heating mixing valve (first heat load bypass flow rate adjustment mechanism)
A Intake point B Low stage discharge point C Intermediate pressure water heat exchanger passage point D Injection junction point E High stage discharge point F First high pressure point G Second high pressure point H Third high pressure point I Fourth high pressure point J Fifth high pressure Point K First low pressure point L Second low pressure point M Third low pressure point N Fourth low pressure point Q Injection intermediate pressure point R Economizer post heat exchange point X Heating branch point Y Heating junction point W Water supply branch point Z Hot water junction point

JP 2004-177067 A

Claims (25)

A heat pump circuit (10) which has at least a low-stage compression mechanism (21), a high-stage compression mechanism (25), an expansion mechanism (5a, 5b), and an evaporator (4), and circulates the primary refrigerant. When,
First branch part (X), second branch part (Y), first branch path (67) connecting the first branch part (X) and the second branch part (Y), the first branch path A second branch path (68) for connecting the first branch portion (X) and the second branch portion (Y) without merging with (67), and a first thermal load processing section (61). A first thermal load circuit (60) through which the first fluid circulates;
The primary refrigerant flowing from the discharge side of the low-stage compression mechanism (21) toward the suction side of the high-stage compression mechanism (25), the first fluid flowing through the first branch passage (67), and A first heat exchanger (40) for exchanging heat between,
A heat exchange is performed between the primary refrigerant flowing from the high-stage compression mechanism (25) toward the expansion mechanism (5) and the first fluid flowing through the second branch path (68). Two heat exchangers (52);
A first flow rate adjusting mechanism capable of adjusting at least one of the flow rate of the first fluid in the first branch path (67) and the flow rate of the first fluid in the second branch path (68). (62)
The temperature of the first fluid flowing through the portion of the first branch (67) that has passed through the first heat exchanger (40), and the second heat exchanger (of the second branch (68)) 52) so as to maintain a condition that satisfies a predetermined temperature condition including a case where the ratio of the temperature of the first fluid flowing through the portion that has passed through 52) is 1, or
The temperature of the first fluid flowing through the portion of the first branch (67) that has passed through the first heat exchanger (40), and the second heat exchanger (of the second branch (68)) 52) so as to reduce the difference between the temperature of the first fluid flowing through the portion that has passed through
A controller (11) for performing flow rate adjustment control for operating the first flow rate adjustment mechanism (62);
A heat pump system (1) comprising: The control unit (11)
While the temperature of the primary refrigerant flowing into the first heat exchanger (40) is equal to or higher than the temperature of the first fluid flowing into the first heat exchanger (40),
While the temperature of the primary refrigerant flowing into the second heat exchanger (52) is equal to or higher than the temperature of the first fluid flowing into the second heat exchanger (52),
Both the temperature of the primary refrigerant flowing into the first heat exchanger (40) and the temperature of the primary refrigerant flowing into the second heat exchanger (52) are required in the first heat load processing unit (61). So that the temperature is equal to or higher than the temperature corresponding to the first heat load.
Controlling the outputs of the low-stage compression mechanism (21) and the high-stage compression mechanism (25);
The heat pump system (1) according to claim 1. The first thermal load circuit (60) includes a portion between the first thermal load processing unit (61) and the first branch portion (X), the first thermal load processing unit (61), and the second branch. A first heat load bypass circuit (69) connecting the portions between the portions (Y), and a first heat capable of adjusting a flow rate of the first fluid passing through the first heat load bypass circuit (69). A load bypass flow rate adjustment mechanism (164);
In the flow rate adjustment control, the control unit (11) includes a target value of the temperature of the first fluid flowing through a portion of the first branch (67) that has passed through the first heat exchanger (40), and the control unit (11). Control is performed so that the target value of the temperature of the first fluid flowing through the portion of the second branch path (68) that has passed through the second heat exchanger (52) exceeds the temperature corresponding to the first heat load. And
The control unit (11) is configured to adjust the first thermal load bypass flow rate adjustment mechanism so that the temperature of the first fluid supplied to the first thermal load processing unit (61) becomes the temperature corresponding to the first thermal load. (164) is operated to adjust the flow rate of the first fluid passing through the first thermal load bypass circuit (69).
The heat pump system (3x) according to claim 2. In the flow rate adjustment control, the control unit (11) includes a target value of the temperature of the first fluid flowing through a portion of the first branch (67) that has passed through the first heat exchanger (40), and the control unit (11). A target value of the temperature of the first fluid flowing through a portion of the second branch path (68) that has passed through the second heat exchanger (52) is controlled to be the temperature corresponding to the first heat load;
The heat pump system (1) according to claim 2. In the flow rate adjustment control, the control unit (11)
To maintain a state where a predetermined compression ratio condition is satisfied, including a case where the ratio of the compression ratio in the low-stage compression mechanism (21) and the compression ratio in the high-stage compression mechanism (25) is 1. Or
In order to reduce the difference between the compression ratio in the low-stage compression mechanism (21) and the compression ratio in the high-stage compression mechanism (25),
Controlling at least one of the low-stage compression mechanism (21), the high-stage compression mechanism (25), and the expansion mechanism (5);
The heat pump system (1) according to any one of claims 2 to 4. When the flow rate adjustment control is performed, the control unit (11) sucks the low-stage compression mechanism (21) when the discharge temperature of the primary refrigerant of the low-stage compression mechanism (21) increases. Performing low-stage suction superheat control to increase the superheat of the primary refrigerant,
The heat pump system (1) according to claim 5. The heat pump circuit (10) passes through the primary refrigerant sucked by the low-stage compression mechanism (21) and the second heat exchanger (52) toward the expansion mechanism (5). A primary inter-refrigerant heat exchanger (8) for exchanging heat with the flowing primary refrigerant;
The controller (11) performs the low-stage suction superheat control using the primary inter-refrigerant heat exchanger (8).
The heat pump system (1) according to claim 6. When the flow rate adjustment control is performed, the control unit (11) is directed from the first heat load processing unit (61) to the first heat exchanger (40) and the second heat exchanger (52). When the temperature of the flowing first fluid rises, the low-stage compression mechanism (21) sucks while lowering the target value of the primary refrigerant discharge temperature of the low-stage compression mechanism (21). Performing a load reduction control to reduce the degree of superheat of the primary refrigerant,
The heat pump system (1) according to any one of claims 5 to 7. A second heat load circuit (90) having the second heat load section (91) and circulating a second fluid;
Heat is generated between the second fluid circulating in the second heat load circuit (90) and the primary refrigerant on the way from the high-stage compression mechanism (25) to the second heat exchanger (52). A third heat exchanger (51) for exchange,
Further equipped with,
The heat pump system (1) according to claim 8. Of the second fluid passing through the second heat load circuit (90), the second fluid heading from the second heat load processing section (91) toward the third heat exchanger (51), and the second heat A fourth heat exchanger (53) that allows heat exchange with the primary refrigerant on the way to the expansion mechanism (5) after passing through the exchanger (52);
The heat pump system (1) according to claim 9. The controller (11) is configured such that a target value of the temperature of the primary refrigerant discharged from the low-stage compression mechanism (21) is greater than a target value of the temperature of the primary refrigerant discharged from the high-stage compression mechanism (25). The temperature of the primary refrigerant passing through the third heat exchanger (51) is close to a target value of the temperature of the primary refrigerant discharged from the low-stage compression mechanism (21). 2 adjusting the circulation amount of the second fluid circulating through the heat load circuit (90);
The heat pump system (1) according to claim 9 or 10. The second heat load processing section (91) is a hot water supply tank (91),
The second fluid is water for hot water supply.
The heat pump system (1) according to any one of claims 9 to 11. In the flow rate adjustment control, the control unit (11) operates the first flow rate adjustment mechanism (62) to pass through the first heat exchanger (40) in the first branch path (67). The lower one of the temperature of the first fluid flowing through the part and the temperature of the first fluid flowing through the part of the second branch (68) that has passed through the second heat exchanger (52) Reduce the flow rate of
The heat pump system (1) according to any one of claims 2 to 12. The first flow rate adjusting mechanism (62) can adjust a ratio between the flow rate of the first fluid flowing through the first branch passage (67) and the flow rate of the first fluid flowing through the second branch passage (68). And
In the flow rate adjustment control, the control unit (11) operates the first flow rate adjustment mechanism (62) to keep the flow rate of the first fluid supplied to the first thermal load processing unit constant. The temperature of the first fluid flowing through the portion of the first branch (67) that has passed through the first heat exchanger (40) and the second heat exchanger (of the second branch (68)) 52) lowering the flow rate ratio of the lower one of the temperatures of the first fluid flowing through the portion that has passed through,
The heat pump system (1) according to claim 13. The first flow rate adjusting mechanism (62) is capable of adjusting the flow rate of the first fluid supplied to the first thermal load processing unit (61),
The controller (11) includes the temperature of the first fluid flowing through a portion of the first branch (67) that has passed through the first heat exchanger (40) and the second branch (68). In the case where the flow rate ratio of the lower temperature out of the temperature of the first fluid flowing through the portion that has passed through the second heat exchanger (52) is small, in the flow rate control, the first flow rate control mechanism (62 ) To lower the flow rate of the first fluid supplied to the first thermal load processing section (61),
The heat pump system (1) according to claim 13. The first flow rate adjusting mechanism (62) adjusts a ratio between the flow rate of the first fluid flowing through the first branch passage (67) and the flow rate of the first fluid flowing through the second branch passage (68). A ratio adjusting unit (64) and a flow rate adjusting unit (63) for adjusting the flow rate of the first fluid supplied to the first thermal load processing unit (61);
In the flow rate adjustment control, the control unit (11) operates the first flow rate adjustment mechanism (62) to pass through the first heat exchanger (40) in the first branch path (67). Of the temperature of the first fluid flowing through the part and the temperature of the first fluid flowing through the part of the second branch (68) passing through the second heat exchanger (52), the first heat Increasing the flow rate that exceeds the temperature corresponding to the load and / or decreasing the flow rate not satisfying the temperature corresponding to the first thermal load,
In the case where the temperature of the first fluid supplied to the first heat load processing unit (61) exceeds the temperature corresponding to the first heat load, the control unit (11) 61) The flow rate of the first fluid supplied to the first thermal load processing section (61) decreases as the temperature of the first fluid supplied to 61) increases.
The heat pump system (1) according to claim 13. First branch path temperature detecting means (67T) for grasping the temperature of the first fluid flowing through a portion of the first branch path (67) that has passed through the first heat exchanger (40), and the second branch path (68) second branch path temperature detecting means (68T) for grasping the temperature of the first fluid flowing through the portion that has passed through the second heat exchanger (52);
Further equipped with,
The heat pump system (1) according to any one of claims 1 to 16. The temperature of the first fluid flowing through the portion of the first branch (67) that has passed through the first heat exchanger (40) and the second heat exchanger (52 of the second branch (68). ) Branching part temperature detecting means (67T) for grasping at least one of the temperatures of the first fluid flowing through the part that has passed
After the first fluid that has passed through the first branch passage (67) and the first fluid that has passed through the second branch passage (68) have joined together, the fluid flows toward the first thermal load processing section (61). A merged part temperature detecting means (65T) for grasping the temperature of the first fluid;
Further equipped with,
The heat pump system (1) according to any one of claims 1 to 16. First branch flow rate detection means (67Q) for grasping the flow rate of the first fluid flowing through the first branch (67);
Second branch flow rate detecting means (68Q) for grasping the flow rate of the first fluid flowing through the second branch (68);
Further equipped with,
The heat pump system (1x) according to any one of claims 1 to 16. Branch partial flow rate detection means (67Q) for grasping at least one of the flow rate of the first fluid flowing through the first branch passage (67) and the flow rate of the first fluid flowing through the second branch passage (68); ,
The first fluid flowing toward the first thermal load processing section (61) after the first fluid flowing through the first branch passage (67) and the first fluid flowing through the second branch passage (68) merge. A combined partial flow rate detection means (65Q) for grasping the flow rate of one fluid;
Further equipped with,
A heat pump system (2x) according to any one of the preceding claims. In the first heat exchanger (40), the primary refrigerant that flows from the discharge side of the low-stage compression mechanism (21) toward the suction side of the high-stage compression mechanism (25), and the first branch path The first fluid flowing through (67) is in a counterflow relationship;
In the second heat exchanger (52), the primary refrigerant that flows from the high-stage compression mechanism (25) toward the expansion mechanism (5) and the first fluid that flows through the second branch path (68). Is in a countercurrent relationship,
A heat pump system (1) according to any one of the preceding claims. The first heat load processing unit (61) is a heating heat exchanger (61) for heating the air in the target space in which it is arranged,
The first fluid is a secondary refrigerant.
The heat pump system (1) according to any one of claims 1 to 21. The low-stage compression mechanism (21) and the high-stage compression mechanism (25) each have a common rotation shaft for performing compression work by being driven to rotate.
The heat pump system (1) according to any one of claims 1 to 22. The controller (11) maintains a discharge pressure of the high-stage compression mechanism (25) at a pressure equal to or higher than a critical pressure of the primary refrigerant in the flow rate control.
Used in an environment where the ambient temperature of the first heat load treatment section (61) is a temperature lower than the critical temperature of the primary refrigerant;
24. A heat pump system (1) according to any one of the preceding claims. The primary refrigerant is carbon dioxide.
A heat pump system (1) according to any one of the preceding claims.