JP2013204851A - Heat pump heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat pump heating device capable of simultaneously performing defrosting operation while performing heating operation of a heated fluid, even under an outdoor air environment of a very low temperature.SOLUTION: A heat pump heating water heater has: a condenser 26 performing heat exchange between a refrigerant and the heated fluid; an evaporator 27 performing heat exchange between the refrigerant and an outdoor air; a low stage compressor 31 compressing the refrigerant sent from the evaporator 27; and an upper stage compressor 32 compressing the refrigerant sent from the low stage compressor 31. A refrigerating circuit 21 composing a heat pump cycle and a bypass circuit 51 branched from the refrigerating circuit 21 and allowing the refrigerant for removing frost adhering to the evaporator 27 to flow are provided. The bypass circuit 51 is connected to the refrigerating circuit 21 at a position where a higher temperature refrigerant than the refrigerant supplied to the evaporator 27 through the refrigerating circuit 21 is circulated, and the refrigerant guided from the position is independent of the refrigerating circuit 21 to be provided so as to be circulated to the evaporator 27.

Description

  The present invention generally relates to a heat pump type heating device, and more particularly to a two-stage compression type heat pump type heating device in which two compressors are provided on a heat pump cycle.

  Regarding a conventional heat pump type heating apparatus, for example, Japanese Patent Application Laid-Open No. 2010-236736 discloses a heat pump type hot water heater for the purpose of shortening the time of a defrosting operation for removing frost generated in an evaporator. (Patent Document 1).

  FIG. 16 is a configuration diagram showing the heat pump type hot water heater disclosed in Patent Document 1. As shown in FIG. Referring to FIG. 16, the heat pump type hot water heater includes a hot water storage circuit 101K, a hot water supply circuit 102K, a refrigerant circuit R, and an intermediate injection circuit M.

  The refrigerant circuit R is configured by connecting refrigerant pipes in an annular shape. On the path of the refrigerant circuit R, a compressor 101 capable of adjusting the capacity of the two-stage compression type, a refrigerant-to-water heat exchanger 103, a cooler 104, an internal heat exchanger 105, and a first electric expansion valve 106 and an evaporator 107 are provided. The intermediate injection circuit M is branched from the refrigerant circuit R between the refrigerant-to-water heat exchanger 103 and the cooler 104, and a part of the refrigerant discharged from the refrigerant-to-water heat exchanger 103 is transferred to the low-pressure side of the compressor 101. It is provided so as to return to the middle of the high pressure side. On the path of the intermediate injection circuit M, an electromagnetic on-off valve 110, a second electric expansion valve 111, and a cooler 104 are provided.

  The heat pump water heater further includes a branch path 113 for removing frost generated and attached to the evaporator 107. The branch passage 113 is provided so as to branch from between the cooler 104 of the intermediate injection circuit M and the intermediate position between the high pressure side and the low pressure side of the compressor 101 and return to the evaporator 107 of the refrigerant circuit R. A defrosting electromagnetic valve 112 is provided on the branch path 113.

  When a temperature of minus 5 ° C. or less is detected, the first electric expansion valve 106 is fully opened, and the defrosting solenoid valve 112 is opened. At this time, the refrigerant is supplied to the refrigerant circuit R from the middle between the low pressure side and the high pressure side of the compressor 101 via the branch path 113. Thus, the medium-pressure high-temperature gas refrigerant via the branch passage 113 and the high-pressure high-temperature gas refrigerant via the fully opened first electric expansion valve 106 flow to the evaporator 107, and frost generated in the evaporator 107 is generated. Removed.

JP 2010-236736 A

  As disclosed in Patent Document 1, a two-stage compression heat pump heating device including a low-pressure compressor and a high-pressure compressor is known. However, in the heat pump type water heater disclosed in Patent Document 1, during the defrosting operation, the first electric expansion valve 106 is completely opened and the defrosting electromagnetic valve 112 is opened, so that the branch path 113 is opened. The flowing refrigerant merges with the refrigerant flowing in the refrigerant circuit R on the upstream side of the evaporator 107. In this case, since the refrigerant has the same pressure between the evaporator 107 and the intermediate position between the low pressure side and the high pressure side of the compressor 101, only the capability of the one-stage compression cycle can be substantially exhibited. As described above, when the capacity of the two-stage compression cycle is limited even though the low-pressure side compressor and the high-pressure side compressor are provided, the heating performance is sufficient in a cryogenic outdoor environment. There are concerns that cannot be demonstrated.

  Further, the outside air temperature when the evaporator is frosted is 0 ° C. or less. However, if the defrosting operation is performed at the outside air temperature, the temperature of the refrigerant in the evaporator must be at least higher than 0 ° C. Don't be. On the other hand, at the time of heating operation, it is necessary to set the temperature of the refrigerant in the evaporator to a temperature lower than the outside air and to absorb heat from the outside air to the refrigerant.

  On the other hand, in the heat pump water heater disclosed in Patent Document 1, during the defrosting operation, the refrigerant flowing through the branch path 113 and the refrigerant flowing through the refrigerant circuit R are merged and sent to the evaporator 107. Then, heat is radiated from the refrigerant to the outside air. In this case, since the dehumidifying operation is a heat dissipation process from the evaporator 107 to the outside air, the heating operation is an endothermic process from the outside air to the evaporator 107, and therefore the defrosting operation and the heating operation cannot be performed simultaneously.

  Accordingly, an object of the present invention is to solve the above-mentioned problem, and even in an extremely low temperature outside air environment, a heat pump type heating capable of simultaneously performing a defrosting operation while performing a heating operation of a fluid to be heated. Is to provide a device.

  A heat pump heating device according to the present invention includes a first heat exchanger that exchanges heat between a refrigerant and a fluid to be heated, a second heat exchanger that exchanges heat between the refrigerant and outdoor air, A refrigeration circuit having a low-pressure side compressor that compresses the refrigerant sent from the second heat exchanger, and a high-pressure side compressor that compresses the refrigerant sent from the low-pressure side compressor, and constituting a heat pump cycle; A bypass circuit that branches from the circuit and flows through the refrigerant for removing frost attached to the second heat exchanger. The bypass circuit is connected to the refrigeration circuit at a position where a refrigerant having a temperature higher than that of the refrigerant supplied to the second heat exchanger flows through the refrigeration circuit. It is provided to circulate through the heat exchanger.

  According to the heat pump type heating apparatus configured as described above, the bypass circuit is provided so as to circulate the refrigerant to the second heat exchanger independently of the refrigeration circuit. A heat absorption process from the air to the second heat exchanger can be performed, and a heat dissipation process from the second heat exchanger to the outdoor air can be performed using a higher temperature refrigerant flowing through the bypass circuit. At this time, the ability of the two-stage compression cycle is exhibited by the low-pressure side compressor and the high-pressure side compressor, so that the defrosting operation is performed while performing the heating operation of the heated fluid even in an extremely low temperature outside air environment. Can be done at the same time.

  Preferably, the refrigeration circuit is sent from the first pressure reducer and the first pressure reducer that depressurizes the refrigerant sent from the first heat exchanger between the first heat exchanger and the second heat exchanger. And a gas-liquid separator that separates the refrigerant into a gas phase and a liquid phase, and a second decompressor that decompresses the liquid-phase refrigerant sent from the gas-liquid separator. The fuel cell further includes an injection circuit that guides a part of the gas-phase refrigerant separated by the gas-liquid separator to a refrigeration circuit between the low-pressure side compressor and the high-pressure side compressor.

  According to the heat pump type heating apparatus configured as described above, the low-temperature refrigerant is mixed in the refrigeration circuit between the low-pressure side compressor and the high-pressure side compressor through the injection circuit. Thereby, the temperature of the refrigerant | coolant discharged from a high pressure side compressor can be reduced, and the reliability of a high pressure side compressor can be improved.

  Preferably, the refrigerant inlet of the bypass circuit is connected to the gas phase side of the gas-liquid separator. Preferably, the refrigerant inlet of the bypass circuit is connected to the liquid phase side of the gas-liquid separator. Preferably, the refrigerant inlet of the bypass circuit is connected to a refrigeration circuit between the first pressure reducer and the gas-liquid separator. Preferably, the refrigerant inlet of the bypass circuit is connected to a refrigeration circuit between the first heat exchanger and the first decompressor. Preferably, the refrigerant inlet of the bypass circuit is connected to a refrigeration circuit between the high-pressure compressor and the first heat exchanger.

  According to the heat pump type heating apparatus configured as described above, a refrigerant having a temperature higher than that of the refrigerant supplied to the second heat exchanger through the refrigeration circuit is drawn into the bypass circuit, and the refrigerant is used to remove the refrigerant from the second heat exchanger. Perform heat dissipation process to outdoor air.

  Preferably, the refrigerant outlet of the bypass circuit is connected to a refrigeration circuit between the low-pressure compressor and the high-pressure compressor. According to the heat pump type heating apparatus configured as described above, the refrigerant that has undergone the heat dissipation process from the second heat exchanger to the outdoor air is returned to the refrigeration circuit between the low-pressure compressor and the high-pressure compressor.

  Preferably, the injection circuit and the bypass circuit each have a first on-off valve and a second on-off valve that are provided on a path of each circuit and permit or block the refrigerant flow. At the time of defrosting the second heat exchanger in which the second on-off valve is opened, the first on-off valve is closed.

  According to the heat pump type heating apparatus configured as described above, instead of mixing the refrigerant in the refrigeration circuit between the low-pressure compressor and the high-pressure compressor through the injection circuit, the refrigerant flowing in the bypass circuit is fed to the low-pressure compressor. The heating operation and the defrosting operation of the fluid to be heated are translated by mixing in the refrigeration circuit between the compressor and the high-pressure compressor.

  Preferably, the refrigerant outlet of the bypass circuit is connected to the liquid phase side of the gas-liquid separator. According to the heat pump type heating apparatus configured as described above, the refrigerant that has undergone the heat dissipation process from the second heat exchanger to the outdoor air is returned to the liquid phase side of the gas-liquid separator.

  Preferably, the injection circuit and the bypass circuit each have a first on-off valve and a second on-off valve that are provided on a path of each circuit and permit or block the refrigerant flow. At the time of defrosting the second heat exchanger in which the second on-off valve is opened, the first on-off valve is opened. According to the heat pump type heating device configured as described above, the heating operation and the defrosting operation of the heated fluid are performed by mixing the refrigerant in the refrigeration circuit between the low-pressure compressor and the high-pressure compressor through the injection circuit. And translate.

  Preferably, outdoor air is supplied to the second heat exchanger from one direction. In the second heat exchanger, the bypass circuit is disposed upstream of the flow of outdoor air supplied to the second heat exchanger with respect to the refrigeration circuit. According to the heat pump heating device configured in this way, frost is more likely to be generated on the upstream side of the flow of outdoor air supplied to the second heat exchanger, and thus a bypass circuit is disposed at that position.

  Also preferably, when the refrigerant circulating through the heat pump cycle is R410A, the condensation temperature of the refrigerant is 55 ° C., and the maximum compression ratio of each of the low-pressure compressor and the high-pressure compressor is 7.5, Even when the evaporation temperature of the refrigerant is −17 ° C. or lower, the heating operation of the fluid to be heated by the first heat exchanger and the defrosting operation of the second heat exchanger can be performed simultaneously.

  As described above, according to the present invention, there is provided a heat pump heating device capable of simultaneously performing a defrosting operation while performing a heating operation of a fluid to be heated even in an extremely low temperature outside air environment. be able to.

It is a circuit diagram which shows the heat pump type heating hot-water supply machine in embodiment of this invention. It is a circuit diagram which shows the 1st modification of the heat pump type heating water heater in FIG. It is a circuit diagram which shows the 2nd modification of the heat pump type heating water heater in FIG. It is a circuit diagram which shows the 3rd modification of the heat pump type heating water heater in FIG. It is a circuit diagram which shows the 4th modification of the heat pump type heating water heater in FIG. It is a circuit diagram which shows the 5th modification of the heat pump type heating water heater in FIG. It is a circuit diagram which shows the 6th modification of the heat pump type heating water heater in FIG. It is a circuit diagram which shows the 7th modification of the heat pump type heating water heater in FIG. It is a circuit diagram which shows the 8th modification of the heat pump type heating water heater in FIG. It is a circuit diagram which shows the 9th modification of the heat pump type heating water heater in FIG. It is a perspective view which shows the positional relationship of the piping of a freezing circuit and a bypass circuit in the evaporator in FIGS. It is a Mollier diagram which shows a 1 stage compression-type refrigerating cycle. It is a Mollier diagram showing a two-stage compression refrigeration cycle. It is a circuit diagram which shows the 1 stage compression-type refrigerating cycle. It is a graph which shows the relationship between external temperature and the temperature of the refrigerant | coolant in an injection circuit. It is a block diagram which shows the heat pump type water heater disclosed by patent document 1. FIG.

  Embodiments of the present invention will be described with reference to the drawings. In the drawings referred to below, the same or corresponding members are denoted by the same reference numerals.

  FIG. 1 is a circuit diagram showing a heat pump type heating water heater in an embodiment of the present invention. Referring to FIG. 1, the heat pump type heating water heater in the present embodiment includes a refrigeration circuit 21, an injection circuit 41, and a bypass circuit 51.

  The refrigeration circuit 21 has a pipe extending in an annular shape and constitutes a heat pump cycle. A condenser 26 and an evaporator 27 are provided on the path of the refrigeration circuit 21. The condenser 26 performs heat exchange between the refrigerant circulating in the heat pump cycle and the fluid to be heated (water or air). The evaporator 27 performs heat exchange between the refrigerant circulating in the heat pump cycle and the outside air (outdoor air).

  On the path of the refrigeration circuit 21, a first expansion valve 36, a gas-liquid separator 38, and a second expansion valve 37 are further provided. The first expansion valve 36, the gas-liquid separator 38 and the second expansion valve 37 are provided between the condenser 26 and the evaporator 27. The first expansion valve 36, the gas-liquid separator 38, and the second expansion valve 37 are arranged in series in the refrigerant flow direction in the refrigeration circuit 21. On the path of the refrigeration circuit 21 from the condenser 26 to the evaporator 27, the first expansion valve 36, the gas-liquid separator 38, and the second expansion valve 37 are arranged in the order given. The first expansion valve 36 is provided as a first pressure reducer that depressurizes the refrigerant sent from the condenser 26. The gas-liquid separator 38 separates the refrigerant sent from the first expansion valve 36 into a gas phase refrigerant and a liquid phase refrigerant. The gas-liquid separator 38 has a gas phase refrigerant space 38a in which a gas phase refrigerant is disposed and a liquid phase refrigerant space 38b in which a liquid phase refrigerant is disposed. The second expansion valve 37 is provided as a second decompressor that decompresses the liquid-phase refrigerant sent from the gas-liquid separator 38.

  A lower compressor 31 and an upper compressor 32 are further provided on the path of the refrigeration circuit 21. The lower compressor 31 and the upper compressor 32 are provided between the evaporator 27 and the condenser 26. The lower compressor 31 and the upper compressor 32 are arranged in series in the refrigerant flow direction in the refrigeration circuit 21. On the path of the refrigeration circuit 21 from the evaporator 27 to the condenser 26, the lower compressor 31 and the upper compressor 32 are arranged in the order given. The lower compressor 31 is provided as a low-pressure compressor that compresses the refrigerant sent from the evaporator 27. The upper compressor 32 is provided as a high-pressure compressor that further compresses the refrigerant sent from the lower compressor 31.

  The injection circuit 41 is provided so as to guide a part of the gas-phase refrigerant separated by the gas-liquid separator 38 to the refrigeration circuit 21 between the lower compressor 31 and the upper compressor 32.

  More specifically, both ends of the injection circuit 41 are connected to the gas phase refrigerant space 38a of the gas-liquid separator 38 and the refrigeration circuit 21 between the lower compressor 31 and the upper compressor 32, respectively. Is provided. The refrigerant inlet of the injection circuit 41 is connected to the gas-phase refrigerant space 38 a of the gas-liquid separator 38, and the refrigerant outlet of the injection circuit 41 is connected to the refrigeration circuit 21 between the lower compressor 31 and the upper compressor 32. ing.

  A first on-off valve 42 is provided on the path of the injection circuit 41. The first opening / closing valve 42 allows or blocks the refrigerant flow in the injection circuit 41 by being opened and closed.

  The bypass circuit 51 is connected to the refrigeration circuit 21 at a position where a refrigerant having a temperature higher than that of the refrigerant supplied to the evaporator 27 through the refrigeration circuit 21 flows, and the refrigerant guided from the position is independent of the refrigeration circuit 21. It is provided to circulate through the evaporator 27.

  More specifically, the bypass circuit 51 has an injection circuit 41 between the gas-phase refrigerant space 38a of the gas-liquid separator 38 and the first on-off valve 42, the first on-off valve 42, and the refrigeration circuit 21 at both ends. Are connected to the injection circuit 41 between them. The refrigerant inlet of the bypass circuit 51 is connected to the gas phase side of the gas-liquid separator 38 via the injection circuit 41, and the refrigerant outlet of the bypass circuit 51 is connected to the lower compressor 31 and the upper compressor 32 via the injection circuit 41. Are connected to the refrigeration circuit 21 between the two.

  In addition to the evaporator 27, a second on-off valve 52 and a third expansion valve 53 are provided on the path of the bypass circuit 51. The evaporator 27, the second on-off valve 52, and the third expansion valve 53 are arranged in series in the refrigerant flow direction in the bypass circuit 51. On the path of the bypass circuit 51 from the gas-phase refrigerant space 38a of the gas-liquid separator 38 toward the refrigeration circuit 21, the evaporator 27, the second on-off valve 52, and the third expansion valve 53 are arranged in the order given. The second on-off valve 52 allows or blocks the refrigerant flow in the bypass circuit 51 by being opened and closed. The third expansion valve 53 is provided for the purpose of adjusting the flow rate of the refrigerant in the bypass circuit 51.

  The reason why the bypass circuit 51 is provided with two valves, the second on-off valve 52 and the third expansion valve 53, is as follows. That is, an electromagnetic expansion valve generally used in an air-conditioning refrigeration cycle cannot be completely closed even when the valve is most closed. For this reason, in this Embodiment, in order to make the flow volume of the refrigerant | coolant in the bypass circuit 51 into zero, the 2nd on-off valve 52 which can close a flow path completely is installed. If the third expansion valve 53 has a structure capable of completely closing the flow path, the second on-off valve 52 can be omitted. In this case, the third expansion valve 53 functions as an on-off valve.

  2 to 10 are circuit diagrams showing modifications of the heat pump type heating / water heater in FIG. In the modification of the heat pump type heating / water heater shown in FIG. 2 to FIG. 10, the connection position of either or both of the refrigerant inlet and the refrigerant outlet of the bypass circuit 51 is different from that of the heat pump type heating / water heater shown in FIG. .

  Referring to FIG. 2, in this modification, the refrigerant inlet of bypass circuit 51 is connected to the gas phase side of gas-liquid separator 38 via injection circuit 41, and the refrigerant outlet of bypass circuit 51 is gas-liquid separated. It is connected to the liquid phase side of the vessel 38.

  Referring to FIG. 3, in this modification, the refrigerant inlet of bypass circuit 51 is connected to the liquid phase side of gas-liquid separator 38, and the refrigerant outlet of bypass circuit 51 is connected to the lower stage compressor via injection circuit 41. It is connected to the refrigeration circuit 21 between 31 and the upper compressor 32.

  Referring to FIG. 4, in this modification, the refrigerant inlet of bypass circuit 51 is connected to the liquid phase side of gas-liquid separator 38, and the refrigerant outlet of bypass circuit 51 is the liquid phase side of gas-liquid separator 38. It is connected to the.

  Referring to FIG. 5, in this modification, the refrigerant inlet of bypass circuit 51 is connected to refrigeration circuit 21 between first expansion valve 36 and gas-liquid separator 38, and the refrigerant outlet of bypass circuit 51 is It is connected to the refrigeration circuit 21 between the lower compressor 31 and the upper compressor 32 via an injection circuit 41.

  With reference to FIG. 6, in this modification, the refrigerant inlet of bypass circuit 51 is connected to refrigeration circuit 21 between first expansion valve 36 and gas-liquid separator 38, and the refrigerant outlet of bypass circuit 51 is The gas-liquid separator 38 is connected to the liquid phase side.

  Referring to FIG. 7, in this modification, the refrigerant inlet of bypass circuit 51 is connected to refrigeration circuit 21 between condenser 26 and first expansion valve 36, and the refrigerant outlet of bypass circuit 51 is an injection circuit. 41 is connected to the refrigeration circuit 21 between the lower compressor 31 and the upper compressor 32.

  Referring to FIG. 8, in this modification, the refrigerant inlet of bypass circuit 51 is connected to refrigeration circuit 21 between condenser 26 and first expansion valve 36, and the refrigerant outlet of bypass circuit 51 is gas-liquid. It is connected to the liquid phase side of the separator 38.

  Referring to FIG. 9, in this modification, the refrigerant inlet of bypass circuit 51 is connected to refrigeration circuit 21 between upper compressor 32 and condenser 26, and the refrigerant outlet of bypass circuit 51 is injection circuit 41. Is connected to the refrigeration circuit 21 between the lower compressor 31 and the upper compressor 32.

  Referring to FIG. 10, in this modification, the refrigerant inlet of bypass circuit 51 is connected to refrigeration circuit 21 between upper compressor 32 and condenser 26, and the refrigerant outlet of bypass circuit 51 is gas-liquid separation. It is connected to the liquid phase side of the vessel 38.

  Next, the refrigerant flow in each circuit of the refrigeration circuit 21, the injection circuit 41, and the bypass circuit 51 will be described.

  First, the refrigeration circuit 21 will be described. First, the refrigerant is compressed by the lower compressor 31. Further, the refrigerant is compressed to a higher pressure by the upper compressor 32.

  The reason for adopting the two-stage compression method in this way is as follows. That is, when the refrigerant temperature difference between the condenser 26 and the evaporator 27 is small, the pressure difference is also small, and when the refrigerant temperature difference between the condenser 26 and the evaporator 27 is large, the pressure difference is large. Become. If the refrigerant temperature difference between the condenser 26 and the evaporator 27 is small, for example, if the outside air temperature is relatively high and the refrigerant temperature in the evaporator 27 is in a range below the compression ratio possible with the one-stage compression method. The heat pump cycle can be configured by a one-stage compression method. On the other hand, when the temperature difference of the refrigerant between the condenser 26 and the evaporator 27 becomes large and the required pressure difference cannot be obtained by the one-stage compression method, it is necessary to adopt the two-stage compression method.

  Next, the refrigerant sent from the upper stage compressor 32 dissipates heat by heat exchange with the heated fluid in the condenser 26. For example, when indoor air is supplied as a fluid to be heated, it can be used as a heat source for heating, and when water is supplied as a fluid to be heated, it is used as a heat source for central heating such as hot water supply or floor heating. be able to. The refrigerant that exchanges heat with the fluid to be heated in the condenser 26 is deprived of heat. As a result, the refrigerant that was in the gas phase at the refrigerant inlet of the condenser 26 becomes a liquid phase at the refrigerant outlet of the condenser 26.

  Next, when the refrigerant sent from the condenser 26 passes through the first expansion valve 36, the pressure and temperature thereof are lowered, and the liquid phase is changed to the gas-liquid mixed state. Next, the gas-liquid mixed refrigerant sent from the first expansion valve 36 is separated into a gas phase and a liquid phase in the gas-liquid separator 38. A part of the liquid-phase refrigerant sent from the liquid-phase refrigerant space 38b passes through the second expansion valve 37, so that its pressure and temperature are further reduced, and a gas-liquid mixed state starts from the liquid phase.

  Next, the gas-liquid mixed state refrigerant sent from the second expansion valve 37 absorbs heat by the heat exchange with the outside air in the evaporator 27 and becomes a gas phase. The refrigerant sent from the evaporator 27 is compressed again by the lower compressor 31. In the refrigeration circuit 21, a heat pump cycle is executed by repeating the process described above.

  The injection circuit 41 will be described. The injection circuit 41 mixes a part of the gas-phase refrigerant disposed in the gas-phase refrigerant space 38a of the gas-liquid separator 38 with the refrigerant discharged from the discharge port of the lower compressor 31, and the mixed refrigerant is in the upper stage. It is provided for the purpose of lowering the temperature of the refrigerant discharged from the discharge port of the upper compressor 32 by sending it to the suction port of the compressor 32.

  The refrigerant in which the refrigerant from the injection circuit 41 and the refrigerant discharged from the discharge port of the lower compressor 31 are mixed has a lower temperature than the refrigerant discharged from the discharge port of the lower compressor 31. That is, the temperature of the refrigerant sucked into the suction port of the upper compressor 32 can be lowered as compared with the case where the injection circuit 41 is not provided, and as a result, the temperature of the refrigerant discharged from the discharge port of the upper compressor 32 is lowered. Can be made. Thereby, the temperature of the refrigerant discharged from the upper compressor 32 is suppressed, and the reliability of the upper compressor 32 can be improved and the operation with a larger pressure difference (temperature difference) can be performed.

  The bypass circuit 51 will be described. The bypass circuit 51 is provided for the purpose of branching off a part of the refrigerant flowing through the refrigeration circuit 21 and supplying it to the evaporator 27 to remove frost attached to the evaporator 27.

  In all the forms shown in FIGS. 1 to 10, when only the heating operation is performed without performing the defrosting operation, the first on-off valve 42 is opened in order to allow the refrigerant to flow through the injection circuit 41. Further, since the defrosting operation is not performed, the second opening / closing valve 52 is closed.

  1 to 10, the refrigerant flow during the defrosting operation is indicated by arrows. Moreover, the x attached | subjected to the arrow of the 1st on-off valve 42 has shown the closed state which does not flow a refrigerant | coolant as a valve.

  The refrigerant outlet of the bypass circuit 51 is connected to the refrigeration circuit 21 between the lower compressor 31 and the upper compressor 32 via the injection circuit 41 in FIGS. 1, 3, 5, 7, and 9. In the embodiment, during the defrosting operation, the second on-off valve 52 and the third expansion valve 53 on the bypass circuit 51 are opened, and the first on-off valve 42 on the injection circuit 41 is closed. As a result, a part of the gas phase refrigerant disposed in the gas phase refrigerant space 38 a of the gas-liquid separator 38 flows through the bypass circuit 51 and is supplied to the evaporator 27. The refrigerant that has radiated heat to the outside air in the evaporator 27 is returned to the refrigeration circuit 21 between the lower compressor 31 and the upper compressor 32. At this time, the refrigerant flowing through the bypass circuit 51 exhibits the function of the injection circuit 41 in addition to the function of defrosting the evaporator 27.

  2, 4, 6, 8, and 10 in which the refrigerant outlet of the bypass circuit 51 is connected to the liquid phase side of the gas-liquid separator 38, on the bypass circuit 51 during the defrosting operation. The second on-off valve 52 and the third expansion valve 53 are opened, and the first on-off valve 42 on the injection circuit 41 is opened. In this embodiment, the refrigerant liquefied by the defrosting of the evaporator 27 in the bypass circuit 51 is returned to the refrigeration circuit 21 on the upstream side of the second expansion valve 37. Thereby, the fall of the flow volume of the refrigerant | coolant supplied to the evaporator 27 can be prevented.

  FIG. 11 is a perspective view showing the positional relationship between the piping of the refrigeration circuit and the bypass circuit in the evaporator shown in FIGS. Referring to FIG. 11, outside air is supplied to evaporator 27 from one direction indicated by arrow 71 by rotation of a fan (not shown). The side surface of the evaporator 27 corresponding to the right side in the figure is an outside air inlet, and the side surface of the evaporator 27 corresponding to the left side in the figure is an outside air outlet.

  The evaporator 27 has heat exchange fins 60 for exchanging heat between the outside air supplied to the evaporator 27 and the refrigerant flowing through the evaporator 27. The refrigeration circuit 21 and the bypass circuit 51 have a refrigerant pipe 66 and a refrigerant pipe 61, respectively. The refrigerant pipe 66 and the refrigerant pipe 61 extend in the vertical direction in FIG. 11 while penetrating the heat exchange fins 60. The refrigerant pipe 66 and the refrigerant pipe 61 are provided as pipes independent from each other, and the refrigerant flowing through each pipe does not mix.

  In the present embodiment, the refrigeration circuit 21 and the bypass circuit 51 have a plurality of refrigerant pipes 66 and a plurality of refrigerant pipes 61, respectively. The plurality of refrigerant pipes 66 are arranged in a direction orthogonal to the outside air flow supplied to the evaporator 27, and the plurality of refrigerant pipes 61 are arranged in a direction orthogonal to the outside air flow supplied to the evaporator 27. The plurality of refrigerant pipes 66 and the plurality of refrigerant pipes 61 are provided at positions shifted in the flow direction of the outside air supplied to the evaporator 27. The refrigerant pipe 66 and the refrigerant pipe 61 are provided at positions that do not overlap each other when viewed from the flow direction of the outside air supplied to the evaporator 27.

  The bypass circuit 51 is disposed upstream of the refrigeration circuit 21 in the outside air flow supplied to the evaporator 27. That is, the refrigerant pipe 61 of the bypass circuit 51 is arranged on the outside air inlet side of the evaporator 27, and the refrigerant pipe 66 of the refrigeration circuit 21 is arranged on the outside air outlet side of the evaporator 27. In the evaporator 27, frost easily attaches to the outside air suction port side. Therefore, by arranging the refrigerant pipe 61 of the bypass circuit 51 at such a position, the frost attached to the evaporator 27 is efficiently removed during the defrosting operation. Can be removed.

  In addition, arrangement | positioning of the refrigerant | coolant piping 66 and the refrigerant | coolant piping 61 shown in FIG. 11 is an example, and is not specifically limited by this invention. The flow of the refrigerant flowing through each pipe may be any of parallel flow, alternating current and cross flow, or may be other flow.

  According to the heat pump type heating hot water supply apparatus in the present embodiment, the defrosting operation can be performed at the same time while performing the heating operation even in an extremely low temperature (for example, −17 ° C. or lower) outside air environment. Then, such an effect produced by the heat pump type heating water heater in this Embodiment is demonstrated.

  FIG. 12 is a Mollier diagram showing a one-stage compression refrigeration cycle. FIG. 13 is a Mollier diagram showing a two-stage compression refrigeration cycle. FIG. 14 is a circuit diagram showing a one-stage compression refrigeration cycle.

  As an example, the refrigerant flowing through the refrigeration circuit 21 is R410A, the refrigerant temperature (condensation temperature) in the condenser 26 is 55 ° C. (the refrigerant pressure at this time is 3.43 MPa), and the degree of supercooling at the outlet of the condenser 26 Is 10 ° C., the degree of superheat at the outlet of the evaporator 27 is 10 ° C., the pressure in the injection circuit 41 in the two-stage compression is the square root of (pressure in the evaporator 27) × (pressure in the condenser 26), compressor The compression process is adiabatic compression (isentropic process), and the maximum compression ratio (permissible maximum value obtained by dividing the compressor discharge pressure by the compressor suction pressure) is 7.5. Assume a condition of FIG. 12 shows a one-stage compression refrigeration cycle under the above conditions, and FIG. 13 shows a two-stage compression refrigeration cycle under the above conditions.

  The Mollier diagram is also called a Ph diagram, and the vertical axis represents pressure and the horizontal axis represents specific enthalpy. The Mollier diagram is a diagram showing characteristics unique to the refrigerant such as the pressure, specific enthalpy, temperature, phase state, enthalpy, and specific volume of the refrigerant used in the refrigeration cycle.

  First, the limitation of the refrigeration cycle of the one-stage compression type will be described in relation to the feasibility of “heating operation under an outside air environment of −17 ° C. or lower”.

  Referring to FIG. 12 and FIG. 14, considering the heating operation state in the one-stage compression refrigeration cycle, first, the gaseous refrigerant is compressed by the compressor 30 and discharged to the condenser 26 side. Under this condition, the discharge pressure of the compressor 30 and the pressure of the refrigerant in the condenser 26 are 3.43 MPa according to the Mollier diagram shown in FIG. The refrigerant gradually changes its phase from a gas state to a liquid state by exchanging heat with the fluid to be heated in the condenser 26. However, the phase change state is 55 ° C. at a constant temperature. The refrigerant is completely liquefied in the condenser 26, and the temperature of the refrigerant at the outlet of the condenser is 45 ° C. under the above condition where the degree of supercooling is 10 ° C.

  Thereafter, the refrigerant expanded by the expansion valve 35 enters a gas-liquid two-phase state, and the refrigerant pressure and temperature are reduced. The temperature of the refrigerant is uniquely determined by the reduced pressure. That is, since the maximum compression ratio of the compressor 30 is 7.5, the minimum pressure on the low pressure side of the compressor 30 is 0.46 MPa, and the temperature of the refrigerant at this time is −16.3 ° C.

  For this reason, in the heating operation, when the temperature of the refrigerant in the condenser 26 needs to be 55 ° C., the temperature of the refrigerant in the evaporator 27 cannot be set lower than −16.3 ° C. Therefore, in terms of the feasibility of “heating operation under an outside air environment of −17 ° C. or lower”, it is theoretically impossible in the one-stage compression refrigeration cycle. Here, it is assumed that the temperature of the refrigerant in the evaporator 27 is about 10 ° C. lower than the outside air temperature. That is, in the one-stage compression refrigeration cycle, when the temperature of the refrigerant in the evaporator 27 is -16.3 ° C, the corresponding outside air temperature is approximately -6.3 ° C.

  Next, the heating operation of the two-stage compression cycle will be considered similarly with reference to the circuit diagram in FIG.

  With reference to FIGS. 8 and 13, first, the gaseous refrigerant is compressed by the upper compressor 32 and discharged to the condenser 26 side. Under this condition, the discharge pressure of the upper compressor 32 and the pressure of the refrigerant in the condenser 26 are 3.43 MPa according to the Mollier diagram shown in FIG. The refrigerant gradually changes its phase from a gas state to a liquid state by exchanging heat with the fluid to be heated in the condenser 26. However, the phase change state is 55 ° C. at a constant temperature. The refrigerant is completely liquefied in the condenser 26, and the temperature of the refrigerant at the outlet of the condenser is 45 ° C. under the above condition where the degree of supercooling is 10 ° C.

  Thereafter, the refrigerant expanded by the first expansion valve 36 is in a gas-liquid two-phase state, and the refrigerant pressure and temperature are reduced to the refrigerant pressure and temperature in the injection circuit 41, respectively. Here, similarly to the above, assuming that the temperature of the refrigerant in the evaporator 27 is about 10 ° C. lower than the outside air temperature, for example, to realize the heating operation under the outside air temperature of −25 ° C. The temperature of the refrigerant in the evaporator 27 must be about −35 ° C. At this time, the pressure of the refrigerant R410A is 0.22 MPa. Under the above conditions, the refrigerant pressure in the injection circuit 41 is 0.87 MPa from the square root of (pressure in the evaporator 27) × (pressure in the condenser 26). 4 ° C.

  The refrigerant sent out from the first expansion valve 36 enters the gas-liquid separator 38 and is separated into a gas phase and a liquid phase therein. The separated liquid refrigerant flows in the direction of the evaporator 27 (direction of the second expansion valve 37), and the separated gas-phase refrigerant flows through the injection circuit 41 and is finally discharged from the lower compressor 31. The combined refrigerant is sucked into the upper compressor 32.

  Note that, during the heating operation, the first on-off valve 42 is opened, and the refrigerant flows through the injection circuit 41. On the other hand, the refrigerant separated into the liquid phase by the gas-liquid separator 38 is in a two-phase state where the pressure is further reduced and lowered by the second expansion valve 37. The refrigerant absorbs heat from the outside air while flowing through the evaporator 27. Thereafter, the refrigerant is sucked, compressed and discharged into the lower compressor 31 and again sucked into the upper compressor 32.

  Due to the above conditions, the maximum compression ratio allowed per compressor is 7.5. On the other hand, the compression ratios of the lower compressor 31 and the upper compressor 32 in the two-stage compression during the heating operation are both 3.95, which is smaller than the allowable maximum compression ratio 7.5. For this reason, heating operation under conditions of a condensation temperature of 55 ° C. and an evaporation temperature of −35 ° C. is possible by performing the two-stage compression.

  Next, the feasibility of “performing defrosting operation while performing heating operation” will be described.

  In the heat pump type heating water heater in the present embodiment, the refrigeration circuit 21 and the bypass circuit 51 are provided as mutually independent paths in the evaporator 27. For this reason, the pressure and temperature of the refrigerant flowing through each circuit of the refrigeration circuit 21 and the bypass circuit 51 can be controlled independently.

  The state of the refrigerant in the bypass circuit 51 during the defrosting operation will be described typically with reference to the circuit in FIG. 8. First, the starting point of the bypass circuit 51 between the condenser 26 and the first expansion valve 36 ( When the third expansion valve 53 and the second on-off valve 52 are opened, the refrigerant flows into the bypass circuit 51. At this time, the refrigerant at the starting point of the bypass circuit 51 is in a liquid phase, its pressure is 3.43 MPa, and its temperature is 45 ° C. The liquid-phase refrigerant flows through the evaporator 27 through another path without being mixed with the refrigerant discharged from the second expansion valve 37, exchanges heat with the evaporator 27, and defrosts.

  When the outside air temperature is −25 ° C., the temperature of the refrigerant in the refrigeration circuit 21 sent from the second expansion valve 37 to the evaporator 27 is −35 ° C. On the other hand, the temperature of the refrigerant in the bypass circuit 51 is 45 ° C. Under the above conditions, when the pressure in the injection circuit 41 is the square root of (pressure in the evaporator) × (pressure in the condenser), the pressure of the refrigerant in the injection circuit 41 at this time is 0.87 MPa. The temperature is 3.4 ° C.

  Thus, since the temperature of the refrigerant in the injection circuit 41 is higher than 0 ° C., as shown in FIG. 1 and the like, the refrigerant in the injection circuit 41 can also be used as a refrigerant that flows to the bypass circuit 51 during the defrosting operation. is there.

  The refrigerant in the bypass circuit 51 that has exited the evaporator 27 passes through the second on-off valve 52 and the third expansion valve 53 in order. Thereafter, the refrigerant drops to the pressure of the injection circuit 41 and merges with the liquid-phase refrigerant between the gas-liquid separator 38 and the second expansion valve 37.

  With such a configuration, in the two-stage compression refrigeration cycle, for example, a heating operation and a defrosting operation can be performed simultaneously even under an outside air temperature of -25 ° C. When performing defrosting operation in addition to heating operation, the amount of heat absorbed from the outside air to the refrigerant in the evaporator 27 is reduced as compared with the heating only operation. For this reason, the heating capacity is reduced by the amount of heat of the refrigerant used for defrosting. At this time, the heating capacity of the condenser 26 can be maintained by increasing the operating speed of the lower compressor 31 or the upper compressor 32 and increasing the total refrigerant flow rate.

  FIG. 15 is a graph showing the relationship between the outside air temperature and the temperature of the refrigerant in the injection circuit. The relationship shown in FIG. 15 is when the refrigerant is R410A and the temperature of the refrigerant in the condenser 26 is about 55 ° C.

  The position of the start point of the bypass circuit 51 needs to be determined so that a refrigerant having a temperature higher than 0 ° C. at which water is frozen is introduced into the bypass circuit 51 for defrosting. Since the refrigerant pressure in the injection circuit 41 is the square root of (pressure in the evaporator) × (pressure in the condenser), as described above, the refrigerant pressure in the evaporator 27 in the bypass circuit 51 is even when the outside air temperature is −25 ° C. As shown in FIG. 15, if the refrigerant upstream of the injection circuit 41 is used, the temperature of the refrigerant is higher than 0 ° C., so that it can be defrosted.

  The configuration of the heat pump type heating / water heater in the embodiment of the present invention described above will be described together. The heat pump type heating / water heater as the heat pump type heating device in the present embodiment includes a refrigerant and a fluid to be heated. A condenser 26 as a first heat exchanger for exchanging heat between them, an evaporator 27 as a second heat exchanger for exchanging heat between the refrigerant and outdoor air, and a refrigerant sent from the evaporator 27 A refrigeration circuit 21 having a lower compressor 31 as a low-pressure compressor that compresses the refrigerant and an upper compressor 32 as a high-pressure compressor that compresses the refrigerant sent from the lower compressor 31, and constituting a heat pump cycle. And a bypass circuit 51 that branches from the refrigeration circuit 21 and through which a refrigerant for removing frost attached to the evaporator 27 flows. The bypass circuit 51 is connected to the refrigeration circuit 21 at a position where a refrigerant having a temperature higher than that of the refrigerant supplied to the evaporator 27 through the refrigeration circuit 21 flows, and the refrigerant guided from the position is independent of the refrigeration circuit 21. It is provided to circulate through the evaporator 27.

  The refrigeration circuit 21 is sent from the first expansion valve 36 and the first expansion valve 36 as a first pressure reducer that depressurizes the refrigerant sent from the condenser 26 between the condenser 26 and the evaporator 27. It further has a gas-liquid separator 38 that separates the refrigerant into a gas phase and a liquid phase, and a second expansion valve 37 as a second decompressor that decompresses the liquid-phase refrigerant sent from the gas-liquid separator 38. The heat pump type hot water heater further includes an injection circuit 41 that guides a part of the gas-phase refrigerant separated by the gas-liquid separator 38 to the refrigeration circuit 21 between the lower compressor 31 and the upper compressor 32. .

  The refrigerant outlet of the bypass circuit is connected to the refrigeration circuit 21 between the lower compressor 31 and the upper compressor 32 or the liquid phase side of the gas-liquid separator 38, and the refrigerant flows through the bypass circuit 51 during the defrosting operation. Is done.

  According to the heat pump type heating water heater in the embodiment of the present invention configured as described above, defrosting is performed while performing the heating operation of the fluid to be heated even in an environment of a low outside temperature of −17 ° C. or less. Driving can be done at the same time.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention is applied to, for example, a heat pump type hot water heater and a heat pump type hot water heater.

  21 Refrigeration Circuit, 26 Condenser, 27 Evaporator, 30 Compressor, 31 Lower Compressor, 32 Upper Compressor, 35 Expansion Valve, 36 First Expansion Valve, 37 Second Expansion Valve, 38 Gas-Liquid Separator, 38a Gas Phase refrigerant space, 38b Liquid phase refrigerant space, 41 Injection circuit, 42 First on-off valve, 51 Bypass circuit, 52 Second on-off valve, 53 Third expansion valve, 60 Heat exchange fin, 61, 66 Refrigerant piping, 101 Compressor , 101K hot water storage circuit, 102K hot water supply circuit, 103 refrigerant-to-water heat exchanger, 104 cooler, 105 internal heat exchanger, 106 first electric expansion valve, 107 evaporator, 110 electromagnetic on-off valve, 111 second electric expansion valve, 112 Solenoid valve for defrosting, 113 branch path.

Claims (13)

A first heat exchanger that exchanges heat between the refrigerant and the fluid to be heated, a second heat exchanger that exchanges heat between the refrigerant and outdoor air, and a refrigerant sent from the second heat exchanger A low-pressure side compressor that compresses the refrigerant, and a high-pressure side compressor that compresses the refrigerant sent from the low-pressure side compressor, and a refrigeration circuit constituting a heat pump cycle,
A bypass circuit that branches from the refrigeration circuit and flows a refrigerant for removing frost attached to the second heat exchanger;
The bypass circuit is connected to the refrigeration circuit at a position where a refrigerant having a temperature higher than that of the refrigerant supplied to the second heat exchanger flows through the refrigeration circuit, and the refrigerant guided from the position is referred to as the refrigeration circuit. A heat pump type heating device provided to flow independently to the second heat exchanger. The refrigeration circuit includes, between the first heat exchanger and the second heat exchanger, a first decompressor that decompresses the refrigerant sent from the first heat exchanger, and a pump that sends the refrigerant from the first decompressor. A gas-liquid separator that separates the obtained refrigerant into a gas phase and a liquid phase; and a second decompressor that decompresses the liquid-phase refrigerant sent from the gas-liquid separator,
2. The injection circuit according to claim 1, further comprising an injection circuit that guides a part of the gas-phase refrigerant separated by the gas-liquid separator to the refrigeration circuit between the low-pressure compressor and the high-pressure compressor. Heat pump type heating device.   The heat pump heating device according to claim 2, wherein a refrigerant inlet of the bypass circuit is connected to a gas phase side of the gas-liquid separator.   The heat pump heating device according to claim 2 or 3, wherein a refrigerant inlet of the bypass circuit is connected to a liquid phase side of the gas-liquid separator.   The heat pump heating device according to any one of claims 2 to 4, wherein a refrigerant inlet of the bypass circuit is connected to the refrigeration circuit between the first pressure reducer and the gas-liquid separator.   The heat pump heating device according to any one of claims 2 to 5, wherein a refrigerant inlet of the bypass circuit is connected to the refrigeration circuit between the first heat exchanger and the first pressure reducer.   The heat pump heating device according to any one of claims 2 to 6, wherein a refrigerant inlet of the bypass circuit is connected to the refrigeration circuit between the high-pressure compressor and the first heat exchanger.   The heat pump heating device according to any one of claims 2 to 7, wherein a refrigerant outlet of the bypass circuit is connected to the refrigeration circuit between the low-pressure compressor and the high-pressure compressor. The injection circuit and the bypass circuit are provided on a path of each circuit, and each has a first on-off valve and a second on-off valve that allow or block the refrigerant flow,
The heat pump heating device according to claim 8, wherein the first on-off valve is closed at the time of defrosting the second heat exchanger in which the second on-off valve is opened.   The heat pump heating device according to any one of claims 2 to 9, wherein a refrigerant outlet of the bypass circuit is connected to a liquid phase side of the gas-liquid separator. The injection circuit and the bypass circuit are provided on a path of each circuit, and each has a first on-off valve and a second on-off valve that allow or block the refrigerant flow,
The heat pump heating device according to claim 10, wherein the first on-off valve is opened at the time of defrosting the second heat exchanger in which the second on-off valve is opened. Outdoor air is supplied to the second heat exchanger from one direction,
The said 2nd heat exchanger WHEREIN: The said bypass circuit is arrange | positioned in the upstream of the flow of the outdoor air supplied to a said 2nd heat exchanger rather than the said refrigerating circuit. The heat pump type heating device according to 1. When the refrigerant circulating through the heat pump cycle is R410A, the refrigerant condensing temperature is 55 ° C., and the maximum compression ratio of each compressor of the low-pressure side compressor and the high-pressure side compressor is 7.5,
The heating operation of the fluid to be heated by the first heat exchanger and the defrosting operation of the second heat exchanger can be performed simultaneously even when the evaporation temperature of the refrigerant is -17 ° C or lower. Item 13. The heat pump heating apparatus according to any one of Items 1 to 12.