JP5999273B2 - Refrigeration cycle equipment - Google Patents

Description

  The present invention relates to a refrigeration cycle apparatus that heats a heat medium with a condenser.

  Patent Document 1 below discloses a refrigeration cycle circuit in which a compressor, a four-way valve, a water heat exchanger (condenser), a pressure reducing device, and an air heat exchanger (evaporator) are connected via a refrigerant pipe, a pump, and water heat In a heat pump type hot water supply apparatus having a water circuit in which an exchanger and a hot water storage tank are connected via a water pipe and storing hot water heated by a hydrothermal exchanger of the refrigeration cycle circuit in the hot water storage tank, as a refrigerant of the refrigeration cycle circuit The one using R410A or R407C is disclosed.

  In the case of an air conditioner using R410A refrigerant, the design pressure on the high pressure side is, for example, 4.25 MPa, and is approximately 65 ° C. when converted to the saturation temperature. In addition, all the pressure descriptions in this specification are absolute pressures. When the R410A refrigerant is used in the refrigeration cycle of the water heater, the design pressure needs to be 4.25 MPa, the same as that of the air conditioner, in order to share the components such as the compressor and the heat exchanger with the air conditioner.

  In Patent Document 1, when the R410A refrigerant is used, when the condensing pressure is 4.75 MPa, the saturation temperature is about 70 ° C., and the incoming water temperature is 5 ° C., the tapping temperature is about 85 ° C. On the other hand, when the upper limit is 4.25 MPa, which is the design pressure of the air conditioner as described above, the saturation temperature is about 65 ° C. and the tapping temperature is about 80 ° C. At this time, the refrigerant temperature at the condenser outlet is set to 10 ° C.

Japanese Unexamined Patent Publication No. 2002-89958 Japanese Unexamined Patent Publication No. 2002-310498 Japanese Unexamined Patent Publication No. 2007-232285 Japanese Unexamined Patent Publication No. 2013-44441 Japanese Unexamined Patent Publication No. 2009-222246 Japanese Unexamined Patent Publication No. 2010-14374 Japanese Unexamined Patent Publication No. 2001-82818

  The incoming water temperature of the condenser of the heat pump type hot water heater is usually the same as the outside air temperature. However, when reheating hot water whose temperature has dropped due to heat dissipation in a hot water storage tank, or when circulating hot water heated by a condenser in a heat exchanger that heats bath water, the incoming water temperature is about 50 ° C. Or higher than that. Assuming that the upper limit of the refrigerant saturation temperature of the condenser is about 65 ° C., the refrigerant at the outlet of the condenser is in a gas-liquid two-phase state or a gas state when the incoming water temperature is high. When the refrigerant at the outlet of the condenser is in a gas-liquid two-phase state or a gas state, the average flow velocity of the refrigerant in the condenser increases, and the pressure loss of the refrigerant increases. Due to the pressure drop due to the pressure loss, a portion where the refrigerant temperature is lower than the incoming water temperature may occur in the condenser. In that case, since the water is deprived of heat by the refrigerant at a portion where the refrigerant temperature is lower than the water temperature, the efficiency of heating the water with the condenser is deteriorated.

  The present invention has been made in order to solve the above-described problems. When the temperature of the heat medium before heating is high, the refrigeration capable of suppressing the refrigerant from being heated from the heat medium by the condenser. An object is to provide a cycle device.

The refrigeration cycle apparatus of the present invention includes a compressor that compresses a refrigerant, a refrigerant channel and a heat medium channel, a first condenser that condenses the refrigerant compressed by the compressor, and a refrigerant of the first condenser. A refrigerant flow path having a smaller cross-sectional area than the flow path and a heat medium flow path, a second condenser for further condensing the refrigerant that has passed through the first condenser, an evaporator for evaporating the refrigerant, a refrigerant and heat A heat medium path for allowing the liquid heat medium to be exchanged to pass through the second condenser and the first condenser in this order; a second condenser bypass path for bypassing the refrigerant flow path or the heat medium flow path of the second condenser; , A flow path control element that varies a bypass amount that is a flow rate of the refrigerant or the heat medium passing through the second condenser bypass passage, and an input heat medium temperature that is a temperature of the heat medium before heat exchange with the refrigerant is a reference temperature. When the amount of bypass is high, the heat transfer medium temperature is To be larger than the bypass quantity of If no, and a control means for controlling the operation of the channel control element, the bypass rate ratio through the second condenser bypass passage of the total flow rate of the coolant or heating medium The control means sets the bypass rate to 0% when the input heat medium temperature is lower than the first reference temperature, and sets the bypass heat rate to be higher than the second reference temperature higher than the first reference temperature. In the case where the bypass rate is 100% and the input heat medium temperature is between the first reference temperature and the second reference temperature, the bypass rate increases continuously or stepwise as the input heat medium temperature increases. in a shall control the operation of the channel control element.

  According to the refrigeration cycle apparatus of the present invention, the condenser is divided into the first condenser and the second condenser, and the second condenser bypass passage that bypasses the refrigerant flow path or the heat medium flow path of the second condenser is provided. When the temperature of the heat medium before heating is high, it is possible to prevent the refrigerant from being heated from the heat medium by the condenser by increasing the amount of the refrigerant or the heat medium that bypasses the second condenser. It becomes possible.

It is a block diagram of the refrigerating cycle apparatus of Embodiment 1 of this invention. It is a perspective view which shows a part of heat exchanger which comprises a 1st condenser and a 2nd condenser. It is a block diagram of the hot water storage type hot-water supply system which has the refrigerating-cycle apparatus and tank unit of Embodiment 1 of this invention. It is a flowchart which shows the control action in the refrigerating-cycle apparatus of Embodiment 1 of this invention. It is a figure which shows operation | movement of the low temperature water-injection driving | operation of the refrigerating-cycle apparatus of Embodiment 1 of this invention. It is a figure which shows an example of the temperature change of the refrigerant | coolant and water in a 1st condenser and a 2nd condenser in the low temperature water_inflow operation of the refrigerating-cycle apparatus of Embodiment 1 of this invention. It is a Ph diagram of the low temperature water intake operation of the refrigeration cycle apparatus of Embodiment 1 of the present invention. It is a figure which shows an example of the relationship between the outside air temperature and incoming water temperature in low temperature incoming water operation. It is a figure which shows the operation | movement of the high temperature water injection operation of the refrigeration cycle apparatus of Embodiment 1 of this invention. It is a figure which shows an example of the temperature change of the refrigerant | coolant and water in a 1st condenser in the high temperature water_inflow operation of the refrigerating-cycle apparatus of Embodiment 1 of this invention. It is a Ph diagram of the high temperature incoming operation of the refrigerating cycle device of Embodiment 1 of the present invention. It is a figure which shows an example of the relationship between the position of the refrigerant | coolant and water in the inside of the 1st condenser of the refrigeration cycle apparatus of Embodiment 1 of this invention, and a 2nd condenser, and temperature. It is a figure which shows the comparison of the compressor discharge temperature of R410A refrigerant | coolant and R32 refrigerant | coolant. It is a figure which shows the relationship between a refrigerant | coolant flow path number ratio and the magnitude | size of the refrigerant | coolant pressure loss of a 1st condenser. It is a figure which shows operation | movement of the low temperature water-injection driving | operation of the refrigerating-cycle apparatus of Embodiment 2 of this invention. It is a figure which shows the operation | movement of the high temperature water injection operation of the refrigeration cycle apparatus of Embodiment 2 of this invention. It is a figure which shows the operation | movement of the middle temperature water-injection driving | operation of the refrigerating-cycle apparatus of Embodiment 3 of this invention. It is a flowchart which shows the control action in the refrigerating-cycle apparatus of Embodiment 3 of this invention. It is a figure which shows the relationship between the incoming water temperature and the bypass rate in the medium temperature incoming water driving | operation of the refrigerating cycle apparatus of Embodiment 3 of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the overlapping description is abbreviate | omitted. Note that the present invention includes all combinations of the embodiments described below.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram of a refrigeration cycle apparatus according to Embodiment 1 of the present invention. As shown in FIG. 1, the refrigeration cycle apparatus 1A of the first embodiment includes a compressor 2, first condensers 3A and 3B, a second condenser 4, an expansion valve 5, an evaporator 6, A refrigerant circuit formed by connecting the accumulator 7 with a refrigerant pipe is provided. The refrigeration cycle apparatus 1 </ b> A further includes a heat medium path 9, a second condenser bypass path 10, a flow path switching valve 11, a blower 12 that blows air to the evaporator 6, an incoming heat medium temperature sensor 13, and a refrigeration cycle. And a control device 50 that controls the operation of the device 1A. The refrigeration cycle apparatus 1A of Embodiment 1 has a function as a heat pump that heats a liquid heat medium. Although the heat medium in the first embodiment is water, the heat medium in the present invention may be antifreeze, brine, or the like. Moreover, although the refrigeration cycle apparatus 1A of the first embodiment is used as a hot water supply apparatus, the refrigeration cycle apparatus in the present invention can also be applied to a heating medium used for purposes other than hot water supply (for example, heating). It is. In the following description, the specific enthalpy [kJ / kg] is simply referred to as enthalpy in order to simplify the description.

  The two first condensers 3A and 3B have the same configuration and are connected in parallel. The first condensers 3 </ b> A and 3 </ b> B have a refrigerant flow path 31 and a heat medium flow path 32. The second condenser 4 has a refrigerant channel 41 and a heat medium channel 42. The compressor 2 compresses the low-pressure refrigerant gas into a high-pressure refrigerant gas. The high-pressure refrigerant gas compressed by the compressor 2 flows into the refrigerant flow path 31 of the first condenser 3A and the refrigerant flow path 31 of the first condenser 3B. The high-pressure refrigerant that has passed through the first condensers 3 </ b> A and 3 </ b> B merges and flows into the refrigerant flow path 41 of the second condenser 4. The first condensers 3A and 3B are functionally one condenser. In the present invention, the first condensers 3A and 3B may be integrated.

  The expansion valve 5 is a decompression device that decompresses and expands the high-pressure refrigerant. The expansion valve 5 is preferably one whose opening degree can be arbitrarily changed. The high-pressure refrigerant that has passed through the refrigerant flow path 41 of the second condenser 4 is decompressed and expanded by the expansion valve 5 and becomes low-pressure refrigerant. This low-pressure refrigerant flows into the evaporator 6.

  The evaporator 6 is a heat exchanger that exchanges heat between the refrigerant and the air. The evaporator 6 causes the refrigerant to absorb the heat of the outside air blown by the blower 12. Although the heat source of the evaporator 6 in this Embodiment 1 is outside air, the heat source of the evaporator in this invention is not restricted to outside air, For example, waste heat, underground heat, ground water, solar hot water, etc. may be sufficient. In the present invention, the fluid cooled by the evaporator may be used for cooling or the like.

  The low-pressure refrigerant that has passed through the evaporator 6 flows into the accumulator 7. Of the refrigerant flowing into the accumulator 7, the refrigerant liquid is stored in the accumulator 7, and the refrigerant gas exits the accumulator 7 and is sucked into the compressor 2. In the refrigerant circuit as described above, a section until the high-pressure refrigerant compressed by the compressor 2 flows into the decompression device is generally referred to as a “high-pressure side”, and the low-pressure refrigerant decompressed by the decompression device is the compressor 2. The section until it is inhaled is called “low pressure side”.

  The heat medium path 9 allows water to pass through the heat medium flow path 42 of the second condenser 4 and the heat medium flow path 32 of the first condensers 3A and 3B in this order. The heat medium path 9 connects the water inlet 91 and the inlet of the heat medium flow path 42 of the second condenser 4, and the outlet of the heat medium flow path 42 of the second condenser 4 and the first condensers 3A and 3B. The inlet of the heat medium flow path 32 is connected, and the outlet of the heat medium flow path 32 of the first condensers 3A and 3B and the water outlet 92 are connected. In the first condensers 3A and 3B, the refrigerant and water are opposed to each other. In the 2nd condenser 4, a refrigerant | coolant and water become a counterflow.

  The second condenser bypass passage 10 bypasses the heat medium passage 42 of the second condenser 4. The flow path switching valve 11 is a three-way valve. The flow path switching valve 11 is installed in the middle of the heat medium path 9 between the water inlet 91 and the inlet of the heat medium flow path 42 of the second condenser 4. One end of the second condenser bypass passage 10 is connected to the flow path switching valve 11, and the other end of the second condenser bypass passage 10 is the outlet of the heat medium flow path 42 of the second condenser 4 and the first condenser 3A, It is connected in the middle of the heat medium path 9 between the inlet of the 3B heat medium flow path 32.

  The flow path switching valve 11 has a state in which the total amount of water flowing in from the water inlet 91 flows to the heat medium flow path 42 of the second condenser 4 and the total amount of water flowing in from the water inlet 91 in the second condenser bypass passage 10. It is possible to switch to the state of flowing. Further, the flow path switching valve 11 may be capable of changing the ratio of distributing the water flowing in from the water inlet 91 to the heat medium flow path 42 of the second condenser 4 and the second condenser bypass passage 10. In the first embodiment, of the total flow rate of water flowing from the water inlet 91, the ratio of passing through the second condenser bypass passage 10 without passing through the second condenser 4 is referred to as “bypass rate”. In the first embodiment, the flow path switching valve 11 corresponds to a flow path control element that varies a bypass amount that is a flow rate of water passing through the second condenser bypass passage 10.

  The incoming heat medium temperature sensor 13 is installed in the middle of the heat medium path 9 between the water inlet 91 and the flow path switching valve 11. The incoming heat medium temperature sensor 13 detects the temperature of the heat medium, that is, water before heat exchange with the refrigerant. Hereinafter, the detected temperature of the incoming heat medium temperature sensor 13 is referred to as “incoming water temperature”.

  The control device 50 is control means for controlling the operation of the refrigeration cycle apparatus 1A. The control device 50 is electrically connected to the compressor 2, the expansion valve 5, the flow path switching valve 11, the blower 12, and the incoming heat medium temperature sensor 13. Other actuators, sensors, user interface devices, and the like may be further connected to the control device 50. The control device 50 includes a processor 50a and a memory 50b that stores a control program, data, and the like. The control device 50 stores the operations of the compressor 2, the expansion valve 5, the flow path switching valve 11, and the blower 12 in the memory 50b based on information detected by each sensor, instruction information from the user interface device, and the like. By controlling according to the program, the operation of the refrigeration cycle apparatus 1A is controlled.

  In the first embodiment, R32 is used as the refrigerant. The advantage of using R32 as a refrigerant will be described later.

  FIG. 2 is a perspective view showing a part of the heat exchanger constituting the first condensers 3 </ b> A and 3 </ b> B and the second condenser 4. As shown in FIG. 2, the heat exchanger 60 has one torsion tube 61 and three refrigerant heat transfer tubes 62, 63, 64. The inside of the torsion pipe 61 constitutes a heat medium flow path. That is, water flows through the torsion pipe 61. The inside of the refrigerant heat transfer tubes 62, 63, 64 constitutes a refrigerant flow path. The refrigerant is divided into three refrigerant heat transfer tubes 62, 63, and 64, and flows in parallel inside them. In FIG. 2, the refrigerant heat transfer tubes 62 and 64 are hatched for the sake of convenience in order to easily distinguish the refrigerant heat transfer tubes 62, 63 and 64. That is, the hatching in FIG. 2 does not mean a cross section. The torsion tube 61 has three spiral grooves 61a, 61b, 61c in parallel on the outer periphery thereof. The refrigerant heat transfer tubes 62, 63, 64 are fitted into the grooves 61a, 61b, 61c, respectively, and are wound spirally along the shapes of the grooves 61a, 61b, 61c. With such a configuration, the contact heat transfer area between the torsion tube 61 and the refrigerant heat transfer tubes 62, 63, 64 can be increased.

  The first condenser 3 </ b> A, the first condenser 3 </ b> B, and the second condenser 4 are each configured by a heat exchanger having substantially the same structure as the heat exchanger 60 described above. That is, the first condenser 3A, the first condenser 3B, and the second condenser 4 each include one heat medium flow path and three refrigerant flow paths. However, in FIG. 1, the heat medium flow paths of the first condenser 3 </ b> A, the first condenser 3 </ b> B, and the second condenser 4 are each represented by one line for simplification.

  As described above, the first condensers 3A and 3B function as one condenser. The first condensers 3A and 3B are configured by connecting two heat exchangers 60 in parallel. Therefore, the first condensers 3A and 3B as a whole have two heat medium passages and six refrigerant passages. The cross-sectional area of the refrigerant flow path of the second condenser 4 is smaller than the cross-sectional area of the refrigerant flow paths of the first condensers 3A and 3B. The reason will be described later. When the refrigerant flow path of the condenser is divided into a plurality of parts, the “cross-sectional area of the refrigerant flow path of the condenser” is the sum of the cross-sectional areas of the plurality of refrigerant flow paths. That is, the cross-sectional area of the refrigerant flow paths of the first condensers 3A and 3B is the sum of the cross-sectional areas of the six refrigerant flow paths, and the cross-sectional area of the refrigerant flow path of the second condenser 4 is three. This is the total cross-sectional area of the refrigerant flow path. If the cross-sectional area of one refrigerant flow path of the first condensers 3A and 3B and the cross-sectional area of one refrigerant flow path of the second condenser 4 are equal, in the case of the first embodiment, the second The cross-sectional area of the refrigerant flow path of the condenser 4 is ½ of the cross-sectional area of the refrigerant flow paths of the first condensers 3A and 3B.

  Note that the first condenser and the second condenser in the present invention are not limited to the twisted tube heat exchanger as described above, and may be other types such as a plate heat exchanger. Further, the number of refrigerant channels and heat medium channels is not limited to the above example.

  FIG. 3 is a configuration diagram of a hot water storage type hot water supply system including the refrigeration cycle apparatus 1 </ b> A of the first embodiment and the tank unit 20. As shown in FIG. 3, a hot water storage tank 21 and a water pump 22 are installed in the tank unit 20. The refrigeration cycle apparatus 1 </ b> A and the hot water storage tank 21 are connected via water channels 23 and 24. In addition, the refrigeration cycle apparatus 1A and the tank unit 20 are connected via an electric wiring (not shown). One end of the water channel 23 is connected to the water inlet 91 of the refrigeration cycle apparatus 1A. The other end of the water channel 23 is connected to the lower part of the hot water storage tank 21 in the tank unit 20. A water pump 22 is installed in the middle of the water channel 23 in the tank unit 20. One end of the water channel 24 is connected to the water outlet 92 of the refrigeration cycle apparatus 1A. The other end of the water channel 24 is connected to the upper part of the hot water storage tank 21 in the tank unit 20. Instead of the illustrated configuration, the water pump 22 may be disposed in the refrigeration cycle apparatus 1A.

  A water supply pipe 25 is further connected to the lower part of the hot water storage tank 21 of the tank unit 20. Water supplied from an external water source such as water supply flows into the hot water storage tank 21 through the water supply pipe 25 and is stored. The hot water storage tank 21 is always kept in a full water state when water flows from the water supply pipe 25. In the tank unit 20, a hot water supply mixing valve 26 is further provided. The hot water supply mixing valve 26 is connected to the upper part of the hot water storage tank 21 through a hot water outlet pipe 27. Further, a water supply branch pipe 28 branched from the water supply pipe 25 is connected to the hot water supply mixing valve 26. One end of a hot water supply pipe 29 is further connected to the hot water supply mixing valve 26. Although not shown, the other end of the hot water supply pipe 29 is connected to a hot water supply terminal such as a faucet, a shower, or a bathtub.

  In the heat storage operation for increasing the heat storage amount of the hot water storage tank 21, the water stored in the hot water storage tank 21 is sent to the refrigeration cycle apparatus 1A through the water channel 23 by the water pump 22 and heated in the refrigeration cycle apparatus 1A. It becomes hot water. The hot water generated in the refrigeration cycle apparatus 1A returns to the tank unit 20 through the water channel 24 and flows into the hot water storage tank 21 from above. By such a heat storage operation, hot water is stored in the hot water storage tank 21 by forming a temperature stratification in which the upper side is high temperature and the lower side is low temperature.

  When hot water is supplied from the hot water supply pipe 29 to the hot water supply terminal, high temperature hot water in the hot water storage tank 21 is supplied to the hot water supply mixing valve 26 through the hot water supply pipe 27 and low temperature water is supplied to the hot water supply pipe through the water supply branch pipe 28. It is supplied to the mixing valve 26. The hot water and low temperature water are mixed by the hot water supply mixing valve 26 and then supplied to the hot water supply terminal through the hot water supply pipe 29. The hot water supply mixing valve 26 adjusts the mixing ratio of the high temperature hot water and the low temperature water so that the hot water supply temperature set by the user is obtained.

  A reheating heat exchanger 30 for reheating the bathtub is further provided in the tank unit 20. Although not shown in the figure, in the tank unit 20, piping for circulating the water in the bathtub to the heat exchanger 30 and the connection destinations of the water channels 23 and 24 from the hot water storage tank 21 to the heat exchanger 30. Piping for switching is provided. In the bathtub reheating operation, the water in the bathtub and the hot water generated in the refrigeration cycle apparatus 1A are circulated to the heat exchanger 30 through these pipes, and the temperature of the bathtub is changed by exchanging heat between them. Can be raised.

  FIG. 4 is a flowchart showing a control operation in the refrigeration cycle apparatus 1A of the first embodiment. In step S1 of FIG. 4, the control device 50 compares the incoming water temperature detected by the incoming heat medium temperature sensor 13 with a preset reference temperature α. In the first embodiment, the reference temperature α = 50 ° C. When the incoming water temperature is lower than the reference temperature α in step S1, the control device 50 proceeds to step S2. In step S2, the refrigeration cycle apparatus 1A performs a low-temperature water entry operation. On the other hand, when the incoming water temperature is equal to or higher than the reference temperature α in step S1, the control device 50 proceeds to step S3. In step S3, the refrigeration cycle apparatus 1A performs a high-temperature water entry operation. The control device 50 controls the operation of the flow path switching valve 11 so that the bypass amount in the high-temperature incoming operation is larger than the bypass amount in the low-temperature incoming operation. In the first embodiment, the bypass rate of the low temperature water intake operation is set to 0%. That is, in step S <b> 2, the control device 50 controls the operation of the flow path switching valve 11 so that the total flow rate of water flowing from the water inlet 91 passes through the second condenser 4. Moreover, in this Embodiment 1, the bypass rate of high temperature water-intake operation is set to 100%. That is, in step S3, the control device 50 controls the operation of the flow path switching valve 11 so that the total flow rate of water flowing from the water inlet 91 passes through the second condenser bypass passage 10 without passing through the second condenser 4. To do.

  In order to prevent frequent switching between the low-temperature incoming operation and the high-temperature incoming operation when the incoming water temperature is close to the reference temperature α, two reference temperatures are provided, and hysteresis is provided for switching between the low-temperature incoming operation and the high-temperature incoming operation. You may make it have.

  When the low-temperature water supplied from the water supply pipe 25 exists below the hot water storage tank 21, the incoming water temperature in the heat storage operation is approximately the same as the outside air temperature. The reference temperature α is higher than the outside air temperature. For this reason, in the heat storage operation when the low-temperature water supplied from the water supply pipe 25 is present in the lower side of the hot water storage tank 21, the incoming water temperature is lower than the reference temperature α. I do.

  On the other hand, in the heat storage operation for reheating the hot water in the hot water storage tank 21 whose temperature has decreased due to heat dissipation or the like, the incoming water temperature may become higher than the reference temperature α. In addition, the incoming water temperature may be higher than the reference temperature α in the bathtub chasing operation. In these cases, the refrigeration cycle apparatus 1A performs a high-temperature water entry operation.

  FIG. 5 is a diagram showing the operation of the low-temperature water entry operation of the refrigeration cycle apparatus 1A of the first embodiment. In the low temperature water intake operation, the water flowing in from the water inlet 91 is heated by the second condenser 4 and then branched into two to flow in parallel to the first condensers 3A and 3B and further heated.

  The refrigerant branches into two after leaving the compressor 2 and flows in parallel to the first condensers 3A and 3B. The refrigerant further branches into three refrigerant flow paths just before the entrance of the heat transfer section of the first condenser 3A. Similarly, the refrigerant further branches into three refrigerant flow paths just before the entrance of the heat transfer section of the first condenser 3B. The refrigerant partially condenses in the first condensers 3A and 3B and enters a gas-liquid two-phase state. The refrigerant that has passed through the first condensers 3 </ b> A and 3 </ b> B flows to the second condenser 4 after joining. Immediately before the entrance of the heat transfer section of the second condenser 4, the refrigerant branches into three refrigerant flow paths. The refrigerant is further condensed in the second condenser 4.

  FIG. 6 is a diagram illustrating an example of temperature changes of the refrigerant and water in the first condensers 3A and 3B and the second condenser 4 in the low-temperature water entry operation of the refrigeration cycle apparatus 1A of the first embodiment. In FIG. 6, the horizontal axis represents the enthalpy of the refrigerant, and the vertical axis represents the temperature. In this example, the temperature difference at the pinch point at which the temperature difference between the refrigerant and water is minimized is about 3K. Further, assuming that the incoming water temperature is 9 ° C., the refrigerant condensing temperature is 62 ° C. (4.11 MPa in saturation pressure), and the refrigerant gas temperature at the inlet of the first condenser 3A, 3B is 126 ° C., the first condenser 3A, The water temperature at the outlet of 3B is 80 ° C., and the temperature of the refrigerant liquid at the outlet of the second condenser 4 is 12 ° C. Thus, according to the refrigeration cycle apparatus 1A of the first embodiment, the high-pressure side pressure can be set to 4.25 MPa or less, which is a design pressure of a general air conditioner, and 80 ° C. hot water can be discharged. For this reason, since the specification of the compressor 2 can be made common with an air conditioner, cost can be reduced. In the following description, the water temperature at the outlets of the first condensers 3A and 3B will be referred to as “hot water temperature”.

  FIG. 7 shows a Ph diagram, that is, a Mollier diagram, of the low-temperature water entry operation of the refrigeration cycle apparatus 1A of the first embodiment. As shown in FIG. 7, in the low-temperature water entry operation, the low-pressure refrigerant gas is compressed from the point E1 to the point A1 by the compressor 2 and becomes high-pressure refrigerant gas. The high-pressure refrigerant gas is cooled from the point A1 to the point B1 by the first condensers 3A and 3B, and starts condensing during that time. Point B1 is in a gas-liquid two-phase state. This high-pressure refrigerant in the gas-liquid two-phase state is further condensed by the second condenser 4 to become a supercooled liquid. That is, the high-pressure refrigerant changes from the point B1 to the point C1 in the second condenser 4. The refrigerant of the supercooled liquid at the point C1 is expanded to the point D1 by the expansion valve 5 and depressurized, and becomes a low-pressure refrigerant in a gas-liquid two-phase state. This gas-liquid two-phase low-pressure refrigerant absorbs heat from the point D1 to the point E1 in the evaporator 6 and evaporates.

  In the low-temperature water entry operation, the refrigerant is supercooled to a temperature close to the water temperature, so that the enthalpy difference of the refrigerant increases, and as a result, the COP of the refrigeration cycle apparatus 1A can be increased. FIG. 8 shows an example of the relationship between the outside air temperature and the incoming water temperature in the low temperature incoming operation. The example in which the incoming water temperature is 9 ° C. shown in FIG. 5 corresponds to the case where the outside air temperature is 7 ° C. As the outside air temperature rises, the incoming water temperature also rises.

  FIG. 9 is a diagram showing the operation of the high-temperature water entry operation of the refrigeration cycle apparatus 1A of the first embodiment. In the high temperature water inlet operation, the water flowing in from the water inlet 91 does not pass through the second condenser 4, passes through the second condenser bypass passage 10, and then branches into two to pass through the first condensers 3 </ b> A and 3 </ b> B. It flows in parallel and is heated. The route through which the refrigerant flows in the high-temperature incoming operation is the same as that in the low-temperature incoming operation. However, since there is no heat exchange with water in the second condenser 4, the refrigerant is not condensed in the second condenser 4.

  FIG. 10 is a diagram illustrating an example of temperature changes of the refrigerant and water in the first condensers 3A and 3B in the high-temperature water entry operation of the refrigeration cycle apparatus 1A of the first embodiment. In FIG. 10, the horizontal axis represents the enthalpy of the refrigerant, and the vertical axis represents the temperature. In this example, the temperature difference at the pinch point at which the temperature difference between the refrigerant and water is minimized is about 3K. Further, assuming that the incoming water temperature is 50 ° C., the refrigerant condensing temperature is 62 ° C. (4.11 MPa in saturation pressure), and the refrigerant gas temperature at the inlet of the first condenser 3A, 3B is 126 ° C., the first condenser 3A, The water temperature at the outlet of 3B, that is, the tapping temperature is 80 ° C.

  FIG. 11 shows a Ph diagram of the high-temperature water entry operation of the refrigeration cycle apparatus 1A of the first embodiment. As shown in FIG. 11, in the high-temperature water entry operation, the low-pressure refrigerant gas is compressed from the point E2 to the point A2 by the compressor 2 to become high-pressure refrigerant gas. The high-pressure refrigerant gas is cooled from the point A2 to the point B2 in the first condensers 3A and 3B, and starts condensing during that time. Point B2 is in a gas-liquid two-phase state. In the second condenser 4, water does not flow and heat exchange is not performed. For this reason, the enthalpy of the refrigerant in the second condenser 4 does not decrease, but the pressure decreases due to pressure loss. That is, the refrigerant changes from the point B2 to the point C2 in the second condenser 4. The refrigerant in the gas-liquid two-phase state at point C2 is expanded and decompressed to the point D2 by the expansion valve 5, and becomes a low-pressure refrigerant in the gas-liquid two-phase state. This gas-liquid two-phase low-pressure refrigerant absorbs heat from the point D2 to the point E2 in the evaporator 6 and evaporates.

  The average refrigerant dryness from the point B2 to the point C2 of the second condenser 4 in the high temperature water inlet operation is higher than the average refrigerant dryness from the point B1 to the point C1 in the second condenser 4 in the low temperature water inlet operation. For this reason, the average refrigerant density in the second condenser 4 in the high temperature water inlet operation is smaller than the average refrigerant density in the second condenser 4 in the low temperature water inlet operation. Further, the average refrigerant dryness from the point D2 to the point E2 of the evaporator 6 in the high temperature water inlet operation is higher than the average refrigerant dryness from the point D1 to the point E1 in the evaporator 6 in the low temperature water inlet operation. For this reason, the average refrigerant density in the evaporator 6 in the high temperature water inlet operation is smaller than the average refrigerant density in the evaporator 6 in the low temperature water inlet operation. For this reason, the high-temperature water input operation requires a smaller amount of refrigerant for the second condenser 4 and the evaporator 6 than the low-temperature water input operation, so that excess refrigerant is generated in the refrigerant circuit. In the high temperature water entry operation, the surplus refrigerant is stored in the accumulator 7 as a refrigerant liquid. Thus, in this Embodiment 1, the accumulator 7 is corresponded to the storage part which stores an excess refrigerant | coolant. However, in the present invention, a liquid receiver (not shown) provided between the second condenser 4 and the expansion valve 5 may be used as a storage unit, or the evaporator 6 may be used as a storage unit. Excess refrigerant may be stored in two or more of the accumulator 7, the liquid receiver and the evaporator 6.

  FIG. 12 is a diagram showing an example of the relationship between the position and temperature of the refrigerant and water in the first condensers 3A and 3B and the second condenser 4 of the refrigeration cycle apparatus 1A of the first embodiment. The vertical axis in FIG. 12 represents temperature. The horizontal axis of FIG. 12 shows the second condenser 4 when the total of one heat medium flow path length of the first condensers 3A and 3B and one heat medium flow path length of the second condenser 4 is 1. Represents the ratio of the distance from the water inlet. Here, the heat medium flow path length is the length of the central axis with respect to the flow direction of the heat medium flow path. The operating conditions of the example shown in FIG. 12 are the same as the operating conditions of FIG. 6 or 10 described above.

  In the example shown in FIG. 12, Lp1: Lp2 = 0..., Assuming that one heat medium flow path length of the first condensers 3A and 3B is Lp1 and one heat medium flow path length of the second condenser 4 is Lp2. 55: 0.45. In the first embodiment, the first condensers 3A and 3B have two heat medium flow paths, and the second condenser 4 has one heat medium flow path, and therefore the heat of the first condensers 3A and 3B. When the total length of the medium flow path is L1, and the total length of the heat medium flow path of the second condenser 4 is L2, L1: L2 = 1.10: 0.45≈2.4: 1.0.

  When the ratio of the heat medium flow path length of the first condensers 3A and 3B and the heat medium flow path length of the second condenser 4 is set as described above, in the low temperature water intake operation where the incoming water temperature is 9 ° C., for example, FIG. As shown in FIG. 3, after the water is heated from 9 ° C. to 50 ° C. by the second condenser 4, the water can be heated from 50 ° C. to 80 ° C. by the first condensers 3A and 3B. Further, in the high temperature water inlet operation where the incoming water temperature is 50 ° C., for example, the water can be heated from 50 ° C. to 80 ° C. with the first condensers 3A and 3B.

According to the refrigeration cycle apparatus 1A of the first embodiment, the following effects can be obtained.
(Effect 1) In the low-temperature water entry operation, the COP can be increased by supercooling the refrigerant with the second condenser 4 and lowering the refrigerant temperature at the outlet of the second condenser 4 to increase the enthalpy difference. . Due to the nature of the refrigerant, when it becomes a supercooled liquid, the flow rate becomes low and the heat transfer coefficient becomes lower than that of the gas-liquid two-phase part. On the other hand, in the first embodiment, the second condenser 4 is configured such that the cross-sectional area of the refrigerant flow path of the second condenser 4 is smaller than the cross-sectional area of the refrigerant flow paths of the first condensers 3A and 3B. It is possible to suppress a decrease in the flow rate of the refrigerant in the supercooled liquid, thereby suppressing a decrease in heat transfer coefficient. For this reason, in the low temperature water intake operation, the efficiency of heat exchange in the second condenser 4 can be improved, and the COP can be further increased. In particular, in the first embodiment, the number of refrigerant channels in the second condenser 4 is smaller than the number of refrigerant channels in the first condensers 3A and 3B, so that the refrigerant in the second condenser 4 is reduced. A decrease in heat transfer rate can be more reliably suppressed.

  (Effect 2) In the high-temperature water entry operation, since the refrigerant in the second condenser 4 is in a gas-liquid two-phase state or gas, the flow velocity is higher than that of the supercooled liquid. For this reason, the refrigerant pressure loss in the second condenser 4 in the high temperature water inlet operation is larger than the refrigerant pressure loss in the second condenser 4 in the low temperature water inlet operation. At this time, since the second condenser 4 has a smaller sectional area of the refrigerant flow path and a smaller number of refrigerant flow paths than the first condensers 3A and 3B, the refrigerant pressure loss is likely to increase. For this reason, in the high-temperature incoming operation, the refrigerant in the second condenser 4 undergoes a temperature drop due to pressure loss. As a result, the temperature difference between the refrigerant and water becomes small, and the amount of heat exchange decreases if the pressure is kept constant. When the refrigerant pressure loss further increases in the second condenser 4, a portion where the refrigerant temperature becomes lower than the incoming water temperature is generated. In a portion where the refrigerant temperature is lower than the water temperature, water is deprived of heat by the refrigerant, and heat is lost. As a result, the efficiency with which the refrigeration cycle apparatus 1A heats water decreases. On the other hand, in the first embodiment, since water is not passed through the second condenser 4 in the high-temperature water-filling operation, even if a portion where the refrigerant temperature is lower than the water-filling temperature occurs in the second condenser 4, Can be reliably suppressed from taking heat away by the refrigerant, so that heat loss can be suppressed. Therefore, it can be reliably suppressed that the efficiency of heating the water by the refrigeration cycle apparatus 1A is reduced. In addition, the first condensers 3A and 3B have a larger cross-sectional area of the refrigerant flow path and a larger number of refrigerant flow paths than the second condenser 4, so that the refrigerant pressure loss is small. For this reason, in the first condensers 3A and 3B, a sufficient heat exchange amount can be ensured without increasing the condensation pressure even in a high-temperature incoming operation with a high incoming water temperature.

Moreover, in this Embodiment 1, the following effects are acquired by using R32 as a refrigerant | coolant.
(Effect 3) FIG. 13 shows a comparison of compressor discharge temperatures of R410A refrigerant and R32 refrigerant. In the example shown in FIG. 13, the compressor suction pressure is 0.81 MPa which is the saturated vapor pressure of R32 at 0 ° C., the compressor discharge pressure is 4.25 MPa which is equivalent to the design pressure of the air conditioner, and the compressor 2 It is assumed that the superheat degree of the sucked refrigerant is 0K and the compressor efficiency is 100%. Under such conditions, the compressor discharge temperature of R410A is 91 ° C., whereas the compressor discharge temperature of R32 is 110 ° C. The degree of superheat is the temperature rise from the evaporation temperature, that is, the saturation temperature. In the high-temperature water entry operation, as described above, an excess refrigerant liquid is stored in the accumulator 7, so that the superheat degree of the refrigerant sucked into the compressor 2 becomes 0K (or 0K or less). When the superheat degree of the refrigerant sucked into the compressor 2 becomes 0K, the compressor discharge temperature of the R410A refrigerant is lowered to 91 ° C. as described above. For this reason, when R410A is used for the refrigerant, it is difficult to increase the temperature of the hot water in the high-temperature water entry operation. On the other hand, the R32 refrigerant can increase the compressor discharge temperature to 110 ° C. even when the superheat degree of the refrigerant sucked into the compressor 2 becomes 0K. For this reason, by using R32 as the refrigerant, the temperature of the hot water in the high temperature water intake operation can be made higher than that of the R410A refrigerant. As a result, when the capacity of the hot water storage tank 21 is the same, the amount of stored heat can be increased. In the refrigeration cycle apparatus 1A according to the first embodiment, when R32 is used as a refrigerant and the design pressure is set to the same level as that of an air conditioner, the hot water temperature is about 80 ° C. at maximum. Accordingly, the hot water storage temperature of the hot water storage tank 21 is about 80 ° C. at the maximum. On the other hand, the hot water temperature of the heat pump water heater using CO ₂ as a refrigerant is about 90 ° C. at the maximum, and the hot water storage temperature is about 90 ° C. at the maximum. For this reason, when the capacity | capacitance of the hot water storage tank 21 is made the same, the heat storage amount becomes larger in the heat pump water heater using the CO ₂ refrigerant. However, since the temperature of hot water supplied from the hot water supply pipe 29 to the hot water supply terminal is about 40 to 60 ° C., there is no problem even if the hot water storage temperature is 80 ° C. Further, in the refrigeration cycle apparatus 1A according to the first embodiment, even when performing a high temperature water inlet operation where the water inlet temperature is about 50 ° C. or higher, the hot water temperature is set to 80 ° C. or higher and an efficient operation can be performed. For this reason, when the hot water storage temperature and the heat storage amount are reduced due to heat radiation from the hot water storage tank 21, etc., the hot water having a reduced temperature in the hot water storage tank 21 is made efficient by performing the heat storage operation by the high temperature water input operation of the refrigeration cycle apparatus 1A. Can be reheated well. Further, the critical temperature of CO ₂ is about 31 ° C., whereas the critical temperature of R 32 is as high as about 78 ° C. For this reason, according to the refrigeration cycle apparatus 1A of the first embodiment, the condensation latent heat of the refrigerant can be used even in the high-temperature water entry operation, so that the operation with a high COP can be performed. In addition, if the hot water storage temperature is too high, heat radiation from the hot water storage tank 21 to the outside air increases, so it is better to store hot water at 80 ° C. and perform heat storage operation again when the heat storage amount decreases than to store hot water at 90 ° C. Heat loss is reduced. In the present invention, the same effect as described above can be obtained not only when a refrigerant whose R32 is 100% is used but also when a refrigerant whose main component is R32 is used. When a refrigerant mainly composed of R32 is used, a refrigerant having a ratio of R32 of 70 mass% or more, more preferably 90 mass% or more may be used.

  Here, a ratio of the number of refrigerant channels of the first condenser to the number of refrigerant channels of the second condenser is defined as a refrigerant channel number ratio. As described above, in the first embodiment, the first condensers 3A and 3B have six refrigerant channels, and the second condenser 4 has three refrigerant channels. Is 2. FIG. 14 is a diagram illustrating a relationship between the ratio of the number of refrigerant channels and the magnitude of refrigerant pressure loss in the first condenser. The vertical axis of FIG. 14 represents the magnitude of the refrigerant pressure loss of the first condenser with 100% when the refrigerant flow rate ratio is 1. As shown in FIG. 14, the refrigerant pressure loss of the first condenser decreases as the refrigerant flow path number ratio increases. However, when the refrigerant flow rate ratio exceeds 2.5, the effect of further reducing the refrigerant pressure loss is reduced. On the other hand, if the ratio of the number of refrigerant channels is too large, the heat transfer rate may decrease due to a decrease in the refrigerant flow rate, which may reduce the amount of heat exchange. As described above, the refrigerant flow rate ratio is preferably about 1.5 to 2.5, and the refrigerant flow rate ratio is particularly preferably 2 as in the first embodiment. In the first embodiment, the first condensers 3A and 3B and the second condenser 4 are constituted by heat exchangers having substantially the same structure. That is, the first condensers 3A and 3B are configured by connecting two heat exchangers having substantially the same structure as the second condenser 4 in parallel. Thereby, the said effect can be achieved by an easy design.

  In the low-temperature water entry operation in the first embodiment, the water bypass rate is set to 0%, and the entire amount of water is heated by the second condenser 4, so that the temperature of the hot water can be increased. However, in the present invention, it is not always necessary to set the water bypass rate to 0% in the low temperature water intake operation, and a small amount of water may be passed through the second condenser bypass passage 10. In the high-temperature water entry operation in the first embodiment, the water bypass rate is 100% and the entire amount of water is passed through the second condenser bypass passage 10, so that the refrigerant takes heat away from the water in the second condenser 4. Can be surely prevented. However, in the present invention, it is not always necessary to set the water bypass rate to 100% in the high-temperature incoming operation, and a small amount of water may be passed through the second condenser 4.

  In the present invention, a first reference temperature and a second reference temperature higher than the first reference temperature are provided. When the incoming water temperature is lower than the first reference temperature, the bypass rate is set to 0%, and the incoming water temperature is the second reference temperature. When the temperature is higher than the temperature, the bypass rate is set to 100%. When the incoming water temperature is between the first reference temperature and the second reference temperature, the bypass rate increases continuously or stepwise as the incoming water temperature increases. The control device 50 may control the operation of the flow path switching valve 11 so as to be higher. Thereby, the transition between the low-temperature incoming operation and the high-temperature incoming operation can be performed smoothly.

Embodiment 2. FIG.
Next, the second embodiment of the present invention will be described with reference to FIG. 15 and FIG. 16. The description will focus on the differences from the first embodiment described above, and the same or corresponding parts will be denoted by the same reference numerals. The description is omitted.

  FIG. 15 is a configuration diagram of a refrigeration cycle apparatus according to Embodiment 2 of the present invention. A refrigeration cycle apparatus 1B according to the second embodiment shown in FIG. 15 is different from the refrigeration cycle apparatus 1A according to the first embodiment in that the second condenser bypass passage 10 and the flow path switching valve 11 are not provided. A condenser bypass passage 16 and a bypass valve 17 are provided. The second condenser bypass passage 16 bypasses the refrigerant flow path 41 of the second condenser 4. One end of the second condenser bypass passage 16 is connected to a refrigerant pipe between the refrigerant flow path 31 of the first condensers 3 </ b> A and 3 </ b> B and the refrigerant flow path 41 of the second condenser 4. The other end of the second condenser bypass passage 16 is connected to a refrigerant pipe between the expansion valve 5 and the evaporator 6. The bypass valve 17 is provided in the middle of the second condenser bypass passage 16 and opens and closes the second condenser bypass passage 16. The bypass valve 17 also has a function of a decompression device that decompresses and expands the high-pressure refrigerant. The bypass valve 17 is preferably one whose opening can be arbitrarily changed. The incoming heat medium temperature sensor 13 is installed in the middle of the heat medium path 9 between the water inlet 91 and the second condenser 4.

  In the second embodiment, of the total flow rate of the refrigerant that has passed through the first condensers 3A and 3B, the ratio that passes through the second condenser bypass passage 16 without passing through the second condenser 4 is referred to as “bypass rate”. . In the second embodiment, the expansion valve 5 and the bypass valve 17 correspond to a flow path control element that varies a bypass amount that is a flow rate of the refrigerant passing through the second condenser bypass passage 16. Further, in the second embodiment, the entire amount of water that flows in from the water inlet 91 passes through the second condenser 4 in both the low-temperature incoming operation and the high-temperature incoming operation.

  The refrigeration cycle apparatus 1B performs a low temperature water inlet operation when the incoming water temperature is lower than the reference temperature α, and performs a high temperature water inlet operation when the incoming water temperature is equal to or higher than the reference temperature α. The reference temperature α is set to 50 ° C. as in the first embodiment. The control device 50 controls the operations of the expansion valve 5 and the bypass valve 17 so that the bypass amount in the high-temperature incoming operation is larger than the bypass amount in the low-temperature incoming operation. In the second embodiment, a description will be given assuming that the bypass rate of the low temperature incoming operation is 0% and the bypass rate of the high temperature incoming operation is 100%.

  FIG. 15 shows the operation of the low-temperature water entry operation of the refrigeration cycle apparatus 1B of the second embodiment. When performing the low-temperature water entry operation, the control device 50 closes the bypass valve 17 at an opening degree at which the refrigerant does not flow. Thereby, the total flow rate of the refrigerant that has passed through the first condensers 3 </ b> A and 3 </ b> B passes through the second condenser 4 and the expansion valve 5, and goes to the evaporator 6. The low temperature water inlet operation of the refrigeration cycle apparatus 1B is substantially in the same state as the low temperature water inlet operation of the refrigeration cycle apparatus 1A of the first embodiment.

  FIG. 16 is a diagram illustrating the operation of the high-temperature water entry operation of the refrigeration cycle apparatus 1B according to the second embodiment. As shown in FIG. 16, when performing the high-temperature water entry operation, the control device 50 opens the bypass valve 17 and closes the expansion valve 5 to an opening degree at which the refrigerant does not flow. Thereby, the total flow rate of the refrigerant that has passed through the first condensers 3 </ b> A and 3 </ b> B passes through the second condenser bypass passage 16 without passing through the second condenser 4. The high-pressure refrigerant that has passed through the first condensers 3 </ b> A and 3 </ b> B and has flowed into the second condenser bypass passage 16 is expanded and depressurized by the bypass valve 17, and travels toward the evaporator 6. In this high-temperature water entry operation, water passes through the second condenser 4, but since the refrigerant does not pass through the second condenser 4, the temperature of the water does not change in the second condenser 4.

  According to the refrigeration cycle apparatus 1B of the second embodiment, the same effects as those of the first embodiment can be obtained. In particular, according to the second embodiment, since the refrigerant does not pass through the second condenser 4 in the high-temperature water entry operation, it is ensured that a portion where the refrigerant temperature is lower than the water inlet temperature is generated in the second condenser 4. Can be suppressed. Therefore, since it is possible to reliably suppress the water from taking heat away by the refrigerant, it is possible to reliably suppress the efficiency of the refrigeration cycle apparatus 1B from heating water. Further, in the high-temperature water-filling operation, the gas-liquid two-phase state or gas refrigerant that has passed through the first condensers 3A and 3B does not have to pass through the second condenser 4 having a small cross-sectional area of the refrigerant flow path. It is possible to avoid the temperature of the refrigerant from dropping due to pressure loss in the condenser 4.

  In addition, since the refrigerant does not pass through the second condenser 4 in the high-temperature water entry operation, the refrigerant pressure loss can be further reduced as compared with the first embodiment. For this reason, also in the high temperature water entry operation, the first condensers 3A and 3B can more reliably suppress the increase in the condensation pressure, and can ensure a sufficient amount of heat exchange.

  In the low-temperature water entry operation according to the second embodiment, the refrigerant bypass rate is set to 0%, and the entire flow rate of the refrigerant is passed through the second condenser 4, so that the temperature of the hot water can be increased. However, in the present invention, the refrigerant bypass rate does not necessarily have to be 0% in the low-temperature water entry operation, and a small amount of the total refrigerant flow rate may be passed through the second condenser bypass passage 16. In the high-temperature water entry operation according to the second embodiment, the refrigerant bypass rate is set to 100%, and the entire flow rate of the refrigerant is passed through the second condenser bypass passage 16, so that the pressure loss of the refrigerant can be more reliably reduced. However, in the present invention, the bypass rate of the refrigerant does not necessarily need to be 100% in the high-temperature water entry operation, and a small amount of the total refrigerant flow rate may be passed through the second condenser 4.

Embodiment 3 FIG.
Next, the third embodiment of the present invention will be described with reference to FIG. 17 to FIG. 19. The description will focus on the differences from the second embodiment described above, and the same or corresponding parts will be denoted by the same reference numerals. The description is omitted.

  FIG. 17 is a configuration diagram of a refrigeration cycle apparatus according to Embodiment 3 of the present invention. As shown in FIG. 17, the equipment configuration of the refrigeration cycle apparatus 1C of the third embodiment is the same as that of the second embodiment, and thus the description thereof is omitted.

  FIG. 18 is a flowchart showing a control operation in the refrigeration cycle apparatus 1C of the third embodiment. In step S11 in FIG. 18, the control device 50 compares the incoming water temperature detected by the incoming heat medium temperature sensor 13 with a preset first reference temperature β. In the third embodiment, the first reference temperature β = 30 ° C. When the incoming water temperature is equal to or lower than the first reference temperature β in step S11, the control device 50 proceeds to step S12. In step S12, the refrigeration cycle apparatus 1C performs a low-temperature water entry operation. This low temperature incoming operation is the same as the low temperature incoming operation of the second embodiment (FIG. 15). That is, in step S12, the control device 50 opens the expansion valve 5 and closes the bypass valve 17 to an opening degree at which the refrigerant does not flow.

  If the incoming water temperature is higher than the first reference temperature β in step S11, the control device 50 proceeds to step S13. In step S13, the control device 50 compares the incoming water temperature with a preset second reference temperature γ. In the third embodiment, the second reference temperature γ = 50 ° C. If the incoming water temperature is equal to or higher than the second reference temperature γ in step S13, the control device 50 proceeds to step S14. In step S14, the refrigeration cycle apparatus 1C performs a high-temperature water entry operation. This high temperature water input operation is the same as the high temperature water input operation (FIG. 16) of the second embodiment. That is, in step S14, the control device 50 opens the bypass valve 17 and closes the expansion valve 5 to an opening degree at which the refrigerant does not flow.

  If the incoming water temperature is lower than the second reference temperature γ in step S13, that is, if the incoming water temperature is between the first reference temperature β and the second reference temperature γ, the control device 50 proceeds to step S15. In step S15, the refrigeration cycle apparatus 1C performs a medium temperature water injection operation.

  FIG. 17 shows the operation of the medium temperature water injection operation of the refrigeration cycle apparatus 1C of the third embodiment. The control device 50 in the medium-temperature water-filling operation causes the expansion valve 5 and the bypass valve 17 so that the refrigerant that has passed through the first condensers 3A and 3B flows separately into the second condenser 4 and the second condenser bypass passage 16. To control the opening degree.

  FIG. 19 is a diagram showing the relationship between the incoming water temperature and the bypass rate in the medium temperature incoming water operation of the refrigeration cycle apparatus 1C of the third embodiment. As shown in FIG. 19, the control device 50 controls the opening degree of the expansion valve 5 and the bypass valve 17 so that the bypass rate continuously increases as the incoming water temperature increases in the intermediate temperature incoming water operation.

Here, when the bypass rate is Rb [%], the refrigerant flow rate passing through the second condenser 4 is Grc, and the refrigerant flow rate passing through the second condenser bypass passage 16 is Grb, the following equation holds.
Rb = Grb / (Grc + Grb) × 100

  In FIG. 12, the first reference temperature β is the water temperature at the position where the dryness of the refrigerant in the second condenser 4 becomes 0, that is, the water temperature at the position where the refrigerant becomes the boundary between the gas-liquid two-phase region and the supercooling region. It is desirable to use as a guide. In the example shown in FIG. 12, the water temperature at the position where the dryness of the refrigerant becomes 0 is about 30 ° C. For this reason, in this Embodiment 3, it is set as 1st reference temperature (beta) = 30 degreeC.

  If the pressure is constant when the entire flow rate of the refrigerant is passed through the second condenser 4, the higher the incoming water temperature, the higher the average refrigerant flow velocity of the second condenser 4, and the lower the refrigerant pressure loss of the second condenser 4. growing. In the third embodiment, when the incoming water temperature is between the first reference temperature β (30 ° C.) and the second reference temperature γ (50 ° C.), a part of the refrigerant flow rate is transferred to the second condenser bypass passage. By performing the medium-temperature water-filling operation that is passed through 16, the refrigerant flow rate of the second condenser 4 can be reduced and the pressure loss can be reduced. For this reason, according to the third embodiment, there is an advantage that the refrigerant pressure loss can be reduced as compared with the second embodiment when the incoming water temperature is between 30 ° C. and 50 ° C.

In the medium-temperature water injection operation, the refrigerant enthalpy difference between the first condensers 3A and 3B is Δh1, the refrigerant enthalpy difference between the second condensers 4 is Δh2, and the refrigerant of the first condensers 3A and 3B and the second condenser 4 as a whole. When the enthalpy difference is Δh, the following equation is established.
Δh = Δh1 + Grc / (Grc + Grb) · Δh2

  In the third embodiment, when the incoming water temperature is between the first reference temperature β and the second reference temperature γ, the refrigerant enthalpy difference of the entire first condenser 3A, 3B and second condenser 4 is as described above. Δh calculated by the equation. On the other hand, when the incoming water temperature is equal to or higher than the first reference temperature β and the total flow rate of the refrigerant is passed through the second condenser bypass passage 16, the entire first condensers 3 </ b> A, 3 </ b> B and the second condenser 4 are The refrigerant enthalpy difference is Δh1. As described above, according to the third embodiment, the refrigerant enthalpy difference can be increased as compared with the case where the total flow rate of the refrigerant is passed through the second condenser bypass passage 16 when the incoming water temperature is equal to or higher than the first reference temperature β. Therefore, COP can be made higher.

  Furthermore, according to the third embodiment, since the intermediate temperature water injection operation is performed between the low temperature water input operation and the high temperature water input operation, transition between these operations can be performed smoothly. In the third embodiment, the opening degree of the expansion valve 5 and the bypass valve 17 is controlled so that the bypass rate continuously increases as the incoming water temperature increases in the intermediate temperature incoming water operation. The opening degree of the expansion valve 5 and the bypass valve 17 may be controlled so that the bypass rate increases stepwise as the incoming water temperature increases during operation.

1A, 1B, 1C Refrigeration cycle apparatus, 2 compressor, 3A, 3B first condenser, 4 second condenser, 5 expansion valve, 6 evaporator, 7 accumulator, 9 heat medium path, 10 condenser bypass path, 11 Flow path switching valve, 12 blower, 13 heat medium temperature sensor, 16 condenser bypass passage, 17 bypass valve, 20 tank unit, 21 hot water storage tank, 22 water pump, 23, 24 water channel, 25 water supply pipe, 26 mixing for hot water supply Valve, 27 Hot water supply pipe, 28 Water supply branch pipe, 29 Hot water supply pipe, 30 Reheating heat exchanger, 31 Refrigerant flow path, 32 Heat medium flow path, 41 Refrigerant flow path, 42 Heat medium flow path, 50 Control device, 50a Processor 50b memory, 60 heat exchanger, 61 twisted tube, 61a, 61b, 61c groove, 62, 63, 64 refrigerant heat transfer tube, 91 water inlet, 92 water outlet

Claims (6)

A compressor for compressing the refrigerant;
A first condenser having a refrigerant flow path and a heat medium flow path for condensing the refrigerant compressed by the compressor;
A second condenser having a refrigerant passage having a smaller cross-sectional area than the refrigerant passage of the first condenser and a heat medium passage, and further condensing the refrigerant that has passed through the first condenser;
An evaporator for evaporating the refrigerant;
A heat medium path through which a liquid heat medium that exchanges heat with the refrigerant passes through the second condenser and the first condenser in this order;
A second condenser bypass passage that bypasses the refrigerant flow path or the heat medium flow path of the second condenser;
A flow path control element that varies a bypass amount that is a flow rate of the refrigerant or the heat medium passing through the second condenser bypass passage;
The bypass amount when the incoming heat medium temperature, which is the temperature of the heat medium before heat exchange with the refrigerant, is higher than the reference temperature, is the bypass amount when the incoming heat medium temperature is lower than the reference temperature. Control means for controlling the operation of the flow path control element so as to be larger than
Equipped with a,
The ratio of passing through the second condenser bypass passage out of the total flow rate of the refrigerant or the heat medium is a bypass rate,
The control means sets the bypass rate to 0% when the input heat medium temperature is lower than the first reference temperature, and sets the bypass heat medium temperature to a second reference temperature higher than the first reference temperature. When the input heat medium temperature is between the first reference temperature and the second reference temperature when the input heat medium temperature is high, the bypass ratio is set to 100%. continuously or to be stepwise increased, the refrigeration cycle device that controls the operation of the channel control element.   The refrigeration cycle apparatus according to claim 1, wherein the second condenser bypass passage bypasses the heat medium flow path of the second condenser.   The refrigeration cycle apparatus according to claim 1, wherein the second condenser bypass passage bypasses the refrigerant flow path of the second condenser. The refrigerant flow path of the first condenser is divided into a plurality of parts,
In any one of claims 1 to 3 ratio to the number of the refrigerant flow path of the second condenser in the number of the refrigerant flow path of the first condenser is 1.5 to 2.5 The refrigeration cycle apparatus described. The refrigeration cycle apparatus according to any one of claims 1 to 4 , wherein the refrigerant is R32, or a main component of the refrigerant is R32. When the incoming heat medium temperature is higher than the reference temperature, the refrigerant in the refrigerant circuit becomes redundant,
The refrigeration cycle apparatus according to any one of claims 1 to 5 , further comprising a storage unit that stores excess refrigerant in the refrigerant circuit.

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