JP5510520B2 - Heat pump water heater - Google Patents

Description

  The present invention relates to a heat pump water heater.

  2. Description of the Related Art A heat pump type hot water heater that generates water by heating water with a refrigerant in a refrigeration cycle is widely used. The heat pump water heater includes a water refrigerant heat exchanger that heats water to make hot water by exchanging heat between the high-temperature refrigerant and water. A solid substance generally called a scale adheres to the inner wall of the water flow path in the water refrigerant heat exchanger. This scale is mainly formed by precipitation of calcium dissolved in water. The higher the water temperature, the lower the solubility of calcium. For this reason, in the case of water with high calcium hardness, calcium carbonate precipitates and scale is generated in the process of heating water in the water-refrigerant heat exchanger. When the scale is accumulated and the flow path is narrowed, the flow path resistance is increased, the water flow rate is lowered, and the operation of the heat pump water heater is adversely affected.

  In Patent Document 1, in order to detect an abnormality in the water circuit due to accumulation of scales, etc., a water flow rate detecting means for detecting the water flow rate of the hot water supply circuit and a pump are operated at a predetermined number of revolutions. There is disclosed a heat pump water heater provided with water circuit abnormality detection means for detecting a flow rate and determining a water circuit abnormality when the flow rate is smaller than a preset water flow rate.

JP 2009-145007 A

  When the water flow path in the water-refrigerant heat exchanger is narrowed due to the accumulation of scale, and the pressure loss in the water flow path becomes excessive, the heating operation for generating hot water cannot be performed. In that case, maintenance such as replacing the water refrigerant heat exchanger with a new one is required. Since heating operation cannot be performed until the maintenance is completed, there is a problem that the hot water supply cannot be used and the convenience of the user is impaired.

  The present invention has been made in order to solve the above-described problems. A heat pump water heater capable of performing a heating operation even when deposits deposited from hot water accumulate in the water-refrigerant heat exchanger. The purpose is to provide.

The heat pump water heater according to the present invention includes a compressor that compresses a refrigerant, a first water refrigerant heat exchanger that exchanges heat between the refrigerant and water, and a second water refrigerant that exchanges heat between the refrigerant and water. Supplying the heat exchanger and refrigerant compressed by the compressor to the first water refrigerant heat exchanger and supplying refrigerant after passing through the first water refrigerant heat exchanger to the second water refrigerant heat exchanger Bypassing the first water refrigerant heat exchanger, a refrigerant path capable of forming a refrigerant circuit, a main water flow path for sending hot water that has passed through the second water refrigerant heat exchanger to the first water refrigerant heat exchanger, and A water flow path including a bypass water flow path and flow path switching means capable of switching between a state in which the bypass water flow path is closed and a state in which the bypass water flow path is opened. Hot water heated by the refrigerant heat exchanger is sent to the first water refrigerant heat exchanger via the main water channel. A first heating operation for supplying hot water further heated by the first water refrigerant heat exchanger to the downstream side of the water flow path, and a second water refrigerant heat exchanger with the bypass water flow path opened. Supply the entire amount of hot water heated to the downstream side via the bypass water flow path, or flow the hot water heated by the second water refrigerant heat exchanger into both the bypass water flow path and the main water flow path is allowed, and a second heating operation is supplied to the downstream side is combined with the hot water passing through the hot water passing through the bypass water flow path and the first coolant-refrigerant heat exchanger, Ri executable der a first water Detection means capable of detecting the narrowing of the flow path due to precipitates deposited from the hot water in the refrigerant heat exchanger, and first when no narrowing of the flow path is detected. Heating operation is selected, and if it is detected that the flow path is narrowed, the second heating operation is selected. In which and selecting means for.
The heat pump water heater according to the present invention includes a compressor that compresses the refrigerant, a first water refrigerant heat exchanger that performs heat exchange between the refrigerant and water, and a second that performs heat exchange between the refrigerant and water. A water refrigerant heat exchanger and a refrigerant compressed by the compressor are supplied to the first water refrigerant heat exchanger and the refrigerant after passing through the first water refrigerant heat exchanger is used as the second water refrigerant heat exchanger. A refrigerant path capable of forming a refrigerant circuit to be supplied to the main water flow path, a main water flow path for sending hot water that has passed through the second water refrigerant heat exchanger to the first water refrigerant heat exchanger, and a first water refrigerant heat exchanger A water flow path including a bypass water flow path to be bypassed, and flow path switching means capable of switching between a state in which the bypass water flow path is closed and a state in which the bypass water flow path is opened. The hot water heated by the water refrigerant heat exchanger of the first water refrigerant heat exchange through the main water flow path First heating operation for supplying hot water further heated by the first water refrigerant heat exchanger to the downstream side of the water flow path, and the second water refrigerant heat exchange with the bypass water flow path opened Supply the entire amount of hot water heated by the cooler to the downstream side via the bypass water flow path, or supply hot water heated by the second water refrigerant heat exchanger to both the bypass water flow path and the main water flow path And the second heating operation in which the hot water that has passed through the bypass water flow path and the hot water that has passed through the first water-refrigerant heat exchanger are combined and supplied to the downstream side can be performed. , A first suction port for sucking refrigerant, a first discharge port for discharging refrigerant sucked from the first suction port, a second suction port for sucking refrigerant, and suction from the second suction port A second discharge port that discharges the discharged refrigerant, and the refrigerant path is configured to discharge the refrigerant discharged from the first discharge port to the first A path leading to the water refrigerant heat exchanger, a path leading the refrigerant that has passed through the first water refrigerant heat exchanger to the second suction port, and the refrigerant discharged from the second discharge port to the second water refrigerant heat And a path leading to the exchanger.

  According to the present invention, the water refrigerant heat exchanger is divided into the first water refrigerant heat exchanger and the second water refrigerant heat exchanger, and the precipitate deposited from the hot water is mainly used as the first water refrigerant heat exchanger. It can be generated in the exchanger. And when a deposit accumulates in the 1st water refrigerant heat exchanger, the bypass water channel which bypasses the 1st water refrigerant heat exchanger is opened, and the hot water which passed the 2nd water refrigerant heat exchanger Since the second heating operation that can pass through the bypass water flow path can be performed, the heating operation can be performed reliably.

It is a block diagram which shows the heat pump water heater of Embodiment 1 of this invention. It is a figure (during the 1st heating operation) which shows typically composition of a refrigerant circuit and a water channel with which a heat pump unit of a heat pump water heater of Embodiment 1 of the present invention is provided. It is a figure (at the time of the 2nd heating operation) which shows typically composition of a refrigerant circuit and a water channel with which a heat pump unit of a heat pump water heater of Embodiment 1 of the present invention is provided. It is the top view which saw through the inside of the heat pump unit of the heat pump water heater of Embodiment 1 of this invention. It is the front view which saw through the inside of the heat pump unit of the heat pump water heater of Embodiment 1 of this invention. It is a figure which shows the relationship between the solubility of calcium carbonate with respect to water, and water temperature. It is a figure which shows the relationship between the dimensionless flow path length of a water refrigerant heat exchanger, and the water temperature in a water refrigerant heat exchanger. It is a figure (at the time of 2nd heating operation) which shows typically the structure of the refrigerant circuit with which the heat pump unit of the heat pump water heater of Embodiment 2 of this invention is equipped, and a water flow path.

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.
Embodiment 1 FIG.
FIG. 1 is a configuration diagram illustrating a heat pump water heater according to Embodiment 1 of the present invention. As shown in FIG. 1, the heat pump water heater of this embodiment includes a heat pump unit 1 and a tank unit 2. In the tank unit 2, a hot water storage tank 2a for storing hot water and a water pump 2b are installed. The heat pump unit 1 and the tank unit 2 are connected to each other through a water pipe 11 and a water pipe 12 and electric wiring (not shown). One end of the water pipe 11 is connected to the water inlet 1 a of the heat pump unit 1. The other end of the water pipe 11 is connected to the lower part of the hot water storage tank 2 a in the tank unit 2. A water pump 2 b is installed in the middle of the water pipe 11 in the tank unit 2. One end of the water pipe 12 is connected to the hot water outlet 1 b of the heat pump unit 1. The other end of the water pipe 12 is connected to the upper part of the hot water storage tank 2 a in the tank unit 2. Instead of the illustrated configuration, the water pump 2b may be disposed in the heat pump unit 1.

  A water supply pipe 13 is further connected to the lower part of the hot water storage tank 2a. Water supplied from an external water source such as water supply flows into the hot water storage tank 2a through the water supply pipe 13 and is stored. The hot water storage tank 2a is always kept full. In the tank unit 2, a hot water supply mixing valve 2c is further provided. The hot water supply mixing valve 2 c is connected to the upper part of the hot water storage tank 2 a via the hot water supply pipe 14. In addition, a water supply branch pipe 15 branched from the water supply pipe 13 is connected to the hot water supply mixing valve 2c. One end of a hot water supply pipe 16 is further connected to the hot water supply mixing valve 2c. Although not shown, the other end of the hot water supply pipe 16 is connected to a hot water supply terminal such as a faucet, a shower, or a bathtub.

  When boiling up the water stored in the hot water storage tank 2a, a heating operation for operating the heat pump unit 1 and the water pump 2b is performed. In the heating operation, water stored in the hot water storage tank 2a is sent to the heat pump unit 1 through the water pipe 11 by the water pump 2b, and is heated in the heat pump unit 1 to become high temperature hot water. The hot water generated in the heat pump unit 1 returns to the tank unit 2 through the water pipe 12 and flows into the hot water storage tank 2a from the upper part. By such a heating operation, hot water is stored in the hot water storage tank 2a so that the upper side becomes hot water and the lower side becomes low temperature water.

  When hot water is supplied from the hot water supply pipe 16 to the hot water supply terminal, hot water in the hot water storage tank 2a is supplied to the hot water mixing valve 2c through the hot water supply pipe 14, and low temperature water is supplied to the hot water supply pipe through the water supply branch pipe 15. It is supplied to the mixing valve 2c. The hot water and low temperature water are mixed by the hot water supply mixing valve 2 c and then supplied to the hot water supply terminal through the hot water supply pipe 16. The hot water supply mixing valve 2c has a function of adjusting the mixing ratio of the hot water and the low temperature water so that the hot water temperature set by the user is obtained.

  The heat pump water heater includes a control unit 50. The control unit 50 is electrically connected to actuators, sensors (not shown), and a user interface device (not shown) included in the heat pump water heater, and controls the operation of the heat pump water heater. Functions as a control means. In FIG. 1, the control unit 50 is installed in the heat pump unit 1, but the installation location of the control unit 50 is not limited to the heat pump unit 1. The control unit 50 may be installed in the tank unit 2. Further, the control unit 50 may be arranged in the heat pump unit 1 and the tank unit 2 so as to be connected to each other so as to communicate with each other.

  2 and 3 are diagrams schematically showing the configuration of the refrigerant circuit and the water flow path provided in the heat pump unit 1, respectively. FIG. 2 shows a state during a first heating operation described later. FIG. 3 shows a state during a second heating operation described later. As shown in FIG. 2, the heat pump unit 1 includes a compressor circuit, a first water refrigerant heat exchanger 4, a second water refrigerant heat exchanger 5, an expansion valve 6, and an evaporator 7, A water flow path through which hot water flows through the first water refrigerant heat exchanger 4 and the second water refrigerant heat exchanger 5. The evaporator 7 in the present embodiment is an air refrigerant heat exchanger that performs heat exchange between air and refrigerant. Moreover, the heat pump unit 1 in the present embodiment further includes a blower 8 that blows air to the evaporator 7 and a high-low pressure heat exchanger 9 that performs heat exchange between the high-pressure side refrigerant and the low-pressure side refrigerant. The compressor 3, the first water refrigerant heat exchanger 4, the second water refrigerant heat exchanger 5, the expansion valve 6, the evaporator 7, and the high / low pressure heat exchanger 9 are connected via a refrigerant pipe as a refrigerant path. Thus, a refrigerant circuit is formed.

  The heat pump unit 1 operates the refrigeration cycle by operating the compressor 3 during the heating operation. The compressor 3 of the present embodiment includes a sealed container 3a, a compression element 3b and an electric element 3c provided in the sealed container 3a, a first suction port 3d, a first discharge port 3e, and a second The suction port 3f and the second discharge port 3g. The refrigerant sucked from the first suction port 3d flows into the compression element 3b. The compression element 3b is driven by the electric element 3c and compresses the refrigerant. The refrigerant compressed by the compression element 3b is discharged from the first discharge port 3e. The refrigerant discharged from the first discharge port 3 e flows through the refrigerant path 10 into the first water refrigerant heat exchanger 4. The refrigerant that has passed through the first water-refrigerant heat exchanger 4 flows through the refrigerant path 17 into the second suction port 3f. The refrigerant flowing into the hermetic container 3a of the compressor 3 from the second suction port 3f cools the electric element 3c by passing between the rotor and the stator of the electric element 3c, and then the second discharge port 3g. It is discharged from. The refrigerant discharged from the second discharge port 3g passes through the refrigerant path 18 and flows into the second water refrigerant heat exchanger 5. The refrigerant that has passed through the second water refrigerant heat exchanger 5 flows into the expansion valve 6 through the refrigerant path 19. The refrigerant that has passed through the expansion valve 6 flows into the evaporator 7 through the refrigerant path 20. The refrigerant that has passed through the evaporator 7 passes through the refrigerant path 21 and is sucked into the compressor 3 from the first suction port 3d. The high-low pressure heat exchanger 9 exchanges heat between the high-pressure refrigerant passing through the refrigerant path 19 and the low-pressure refrigerant passing through the refrigerant path 21. As the refrigerant, a refrigerant capable of producing high-temperature hot water, for example, a refrigerant such as carbon dioxide, R410A, propane, or propylene is suitable, but is not particularly limited thereto.

  The heat pump unit 1 includes a three-way valve 22 as a flow path switching unit, a water flow path 23 that connects the water inlet 1 a and the inlet of the second water refrigerant heat exchanger 5, and a second water refrigerant heat exchanger 5. A water passage 24 connecting the outlet and the three-way valve 22, a main water passage 25 connecting the three-way valve 22 and the inlet of the first water refrigerant heat exchanger 4, and an outlet of the first water refrigerant heat exchanger 4 And a water passage 26 that connects the hot water outlet 1b, and a bypass water passage 27 that connects the three-way valve 22 and the middle of the water passage 26. The bypass water flow path 27 is a water flow path that bypasses the first water refrigerant heat exchanger 4. That is, the bypass water flow path 27 is a flow path that allows communication between the upstream side and the downstream side of the first water refrigerant heat exchanger 4. The three-way valve 22 connects the water channel 24 to the main water channel 25 and closes the bypass water channel 27, and the second state connects the water channel 24 to the bypass water channel 27 and closes the main water channel 25. It is possible to switch to the state.

  The heat pump water heater of this embodiment can selectively execute the first heating operation and the second heating operation as the heating operation. When the first heating operation is executed, the three-way valve 22 is set to the first state. As shown in FIG. 2, during the first heating operation, the water flowing in from the water inlet 1 a flows into the second water refrigerant heat exchanger 5 through the water channel 23, and the second water refrigerant heat exchanger 5. It is heated by the heat of the refrigerant. Hot water generated by being heated in the second water refrigerant heat exchanger 5 flows into the first water refrigerant heat exchanger 4 through the water flow path 24, the three-way valve 22 and the main water flow path 25, 1 is further heated by the heat of the refrigerant in the water refrigerant heat exchanger 4. Hot water that has been heated further by being further heated in the first water refrigerant heat exchanger 4 reaches the outlet 1b through the water flow path 26, and is supplied to the tank unit 2 through the water pipe 12. .

  When executing the second heating operation, the three-way valve 22 is set to the second state. As shown in FIG. 3, during the second heating operation, the water flowing in from the water inlet 1 a flows into the second water refrigerant heat exchanger 5 through the water flow path 23, and the second water refrigerant heat exchanger 5. It is heated by the heat of the refrigerant. The hot water generated by being heated in the second water refrigerant heat exchanger 5 does not pass through the first water refrigerant heat exchanger 4, but the water flow path 24, the three-way valve 22, the bypass water flow path 27 and the water flow path. 26, the hot water outlet 1 b is reached, and the water pipe 12 is supplied to the tank unit 2.

  In the following description, the case where the first heating operation is executed will be described unless otherwise noted. The high-temperature and high-pressure gas refrigerant discharged from the first discharge port 3 e of the compressor 3 decreases in temperature while dissipating heat while passing through the first water-refrigerant heat exchanger 4. In the present embodiment, the refrigerant whose temperature has decreased while passing through the first water refrigerant heat exchanger 4 flows into the sealed container 3a from the second suction port 3f and cools the electric element 3c, whereby the electric element The temperature of 3c and the surface temperature of the sealed container 3a can be lowered. As a result, the motor efficiency of the electric element 3c can be improved, and the heat dissipation loss from the surface of the sealed container 3a can be reduced. The refrigerant rises in temperature by removing heat from the electric element 3 c and then flows into the second water-refrigerant heat exchanger 5 and decreases in temperature while dissipating heat while passing through the second water-refrigerant heat exchanger 5. The high-pressure refrigerant whose temperature has been lowered passes through the expansion valve 6 after heating the low-pressure refrigerant while passing through the high-low pressure heat exchanger 9. By passing through the expansion valve 6, the refrigerant is decompressed to a low-pressure gas-liquid two-phase state. The refrigerant that has passed through the expansion valve 6 absorbs heat from the outside air while passing through the evaporator 7 and is evaporated into gas. The low-pressure refrigerant exiting the evaporator 7 is heated by the high-low pressure heat exchanger 9 and then sucked into the compressor 3 and circulated.

  If the high-pressure side refrigerant pressure is equal to or higher than the critical pressure, the refrigerant in the first water refrigerant heat exchanger 4 and the second water refrigerant heat exchanger 5 decreases in temperature without undergoing a gas-liquid phase transition in a supercritical state. To dissipate heat. If the high-pressure side refrigerant pressure is equal to or lower than the critical pressure, the refrigerant radiates heat while liquefying. In the present embodiment, it is preferable to set the high-pressure side refrigerant pressure to be equal to or higher than the critical pressure by using carbon dioxide or the like as the refrigerant. When the high-pressure side refrigerant pressure is equal to or higher than the critical pressure, the liquefied refrigerant does not flow into the sealed container 3a from the second suction port 3f, and the liquefied refrigerant does not adhere to the electric element 3c. The rotational resistance of the electric element 3c can be reduced. Further, since the liquefied refrigerant does not flow into the sealed container 3a from the second suction port 3f, there is an advantage that the refrigerating machine oil is prevented from being diluted by the refrigerant.

  The controller 50 controls the temperature of hot water supplied from the heat pump unit 1 to the tank unit 2 (hereinafter referred to as “hot water temperature”) to be a target hot water temperature during the first and second heating operations. To do. The target hot water temperature is set to 65 ° C. to 90 ° C., for example. In this embodiment, the control part 50 controls the tapping temperature by adjusting the rotation speed of the water pump 2b. The control unit 50 detects the tapping temperature with a temperature sensor (not shown) provided in the water flow path 26, and increases the rotation speed of the water pump 2b when the tapping temperature detected is higher than the target tapping temperature. If the hot water temperature is lower than the target hot water temperature, the rotational speed of the water pump 2b is corrected. In this way, the control unit 50 can perform control so that the tapping temperature matches the target tapping temperature. However, in the present invention, the temperature of the hot water may be controlled by controlling the temperature of the refrigerant discharged from the first discharge port 3e of the compressor 3 or the rotational speed of the compressor 3.

  FIG. 4 is a plan view of the inside of the heat pump unit 1 seen through. FIG. 5 is a front view of the heat pump unit 1 seen through. In FIG. 4 and FIG. 5, the expansion valve 6, the high / low pressure heat exchanger 9, the three-way valve 22, the refrigerant path, the piping forming the water flow path, and the like are omitted. As shown in these drawings, the heat pump unit 1 includes a housing 30 that houses component devices. A partition member 31 is provided in the housing 30. The interior of the housing 30 is partitioned by a partition member 31 to form a plurality of chambers. In the present embodiment, a machine chamber 32 and an air passage chamber 33 are formed in the housing 30. In the machine room 32, the compressor 3 and the 1st water refrigerant | coolant heat exchanger 4 are installed. The first water-refrigerant heat exchanger 4 is arranged in a state of standing alongside the compressor 3. The first water refrigerant heat exchanger 4 is preferably covered with a heat insulating material (not shown).

  In the air passage chamber 33, the second water refrigerant heat exchanger 5, the evaporator 7, and the blower 8 are installed. The second water-refrigerant heat exchanger 5 is accommodated in a hard storage case 34 having a waterproof property made of metal or the like, and is covered with a heat insulating material (not shown) in the storage case 34. The storage case 34 is installed in the lower part of the air passage chamber 33. The blower 8 is installed on the storage case 34. The evaporator 7 is substantially L-shaped in a plan view, and is disposed so as to cover the back surface and one side surface of the air passage chamber 33. By operating the blower 8, outside air is introduced into the air passage chamber 33 and flows through the evaporator 7.

  In the present embodiment, since the second water refrigerant heat exchanger 5 is installed in the air passage chamber 33 through which the outside air flows, the second water refrigerant heat exchanger 5 is housed and protected in the housing case 34. There is a need. On the other hand, since the 1st water refrigerant heat exchanger 4 is installed in the machine room 32 where external air does not distribute | circulate, there is no problem even if it does not accommodate in a container.

  In the heat pump unit 1, calcium carbonate or the like contained in water is deposited, so that a deposit generally called a scale adheres to the inner wall of the flow path. FIG. 6 is a diagram showing the relationship between the solubility of calcium carbonate in water and the water temperature. As shown in FIG. 6, the solubility of calcium carbonate decreases as the water temperature increases. For this reason, a scale is easy to generate | occur | produce, so that water temperature becomes high. In the heat pump unit 1, the supplied water is first heated by the second water refrigerant heat exchanger 5 to rise in temperature, and then heated by the first water refrigerant heat exchanger 4 to further rise in temperature. . That is, the water temperature in the first water refrigerant heat exchanger 4 is higher than the water temperature in the second water refrigerant heat exchanger 5. For this reason, the scale is easily generated in the first water-refrigerant heat exchanger 4 and hardly generated in the second water-refrigerant heat exchanger 5. Therefore, in the secular change of the heat pump water heater of the present embodiment, even if the flow path is narrowed due to accumulation of scale inside the first water refrigerant heat exchanger 4, the second water refrigerant heat exchanger In 5, the flow path is not narrowed by the scale.

  In the heat pump water heater of the present embodiment, the first heating operation is performed until the scale accumulates in the first water refrigerant heat exchanger 4. On the other hand, when the scale is accumulated in the first water refrigerant heat exchanger 4 and the flow path is narrowed to increase the pressure loss, it becomes difficult to perform the first heating operation. Two heating operations can be performed. As described above, the amount of scale generated in the second water refrigerant heat exchanger 5 is extremely smaller than that of the first water refrigerant heat exchanger 4. For this reason, even if the scale is accumulated in the first water refrigerant heat exchanger 4, the scale is not accumulated in the second water refrigerant heat exchanger 5. In the second heating operation, when the bypass water flow path 27 is opened, hot water generated by being heated in the second water refrigerant heat exchanger 5 passes through the first water refrigerant heat exchanger 4. Instead, it flows through the bypass water flow path 27 to the hot water outlet 1b. For this reason, even if the scale accumulates inside the first water refrigerant heat exchanger 4, the pressure loss in the water flow path does not increase, so the second heating operation can be carried out smoothly. Thus, according to the heat pump water heater of the present embodiment, when the scale accumulates inside the first water refrigerant heat exchanger 4 and the pressure loss of the first water refrigerant heat exchanger 4 becomes excessive. The three-way valve 22 can be switched from the first state to the second state, and the second heating operation can be performed instead of the first heating operation. For this reason, since the heating operation does not become infeasible due to the accumulation of scales, the convenience for the user can be improved.

  The heat pump water heater of the present embodiment detects that the flow path is narrowed due to accumulation of scale in the first water-refrigerant heat exchanger 4, and the first heating operation is performed based on the detection result. The second heating operation is automatically selected. Any method may be used to determine whether or not the flow path is narrowed due to the accumulation of scale in the first water-refrigerant heat exchanger 4. For example, the control unit 50 executes the first heating operation. By implementing any of the following methods, it is possible to determine whether or not the flow path is narrowed due to the accumulation of scale in the first water-refrigerant heat exchanger 4.

  (1) A temperature sensor (not shown) indicates a temperature difference between the outlet water temperature and the inlet water temperature of the first water refrigerant heat exchanger 4 and a temperature difference between the outlet water temperature and the inlet water temperature of the second water refrigerant heat exchanger 5. )). The ratio of the temperature difference between the outlet water temperature and the inlet water temperature of the first water refrigerant heat exchanger 4 to the temperature difference between the outlet water temperature and the inlet water temperature of the second water refrigerant heat exchanger 5 is equal to or higher than the first determination value. In some cases, the heat exchange capacity of the first water refrigerant heat exchanger 4 is normal, and it is determined that the flow path is not narrowed due to accumulation of scale in the first water refrigerant heat exchanger 4. be able to. On the other hand, the ratio of the temperature difference between the outlet water temperature of the first water refrigerant heat exchanger 4 and the inlet water temperature to the temperature difference between the outlet water temperature and the inlet water temperature of the second water refrigerant heat exchanger 5 is When the value is lower than 1 determination value, the heat exchange capacity of the first water refrigerant heat exchanger 4 is reduced, and the flow path is narrowed due to accumulation of scale in the first water refrigerant heat exchanger 4. Can be determined to occur.

  (2) The temperature difference between the inlet refrigerant temperature and the outlet refrigerant temperature of the first water refrigerant heat exchanger 4 is detected by a temperature sensor (not shown). When the temperature difference between the inlet refrigerant temperature and the outlet refrigerant temperature of the first water refrigerant heat exchanger 4 is equal to or greater than the second determination value, the heat exchange capability of the first water refrigerant heat exchanger 4 is normal. It can be determined that the flow path is not narrowed due to the accumulation of scale in the first water refrigerant heat exchanger 4. On the other hand, when the temperature difference between the inlet refrigerant temperature and the outlet refrigerant temperature of the first water refrigerant heat exchanger 4 is lower than the second determination value, the heat of the first water refrigerant heat exchanger 4 is It can be determined that the exchange capacity is reduced and the flow path is narrowed due to the accumulation of scale in the first water-refrigerant heat exchanger 4.

  (3) The rotation speed of the water pump 2b is controlled by the control unit 50, and the resistance of the water circuit increases due to the narrowing of the flow path due to the accumulation of scale in the first water refrigerant heat exchanger 4. Then, in order to ensure a required water flow rate, it correct | amends in the direction where the rotation speed of the water pump 2b becomes high. For this reason, if the narrowing of the flow path due to the accumulation of scale occurs in the first water refrigerant heat exchanger 4, the rotational speed of the water pump 2b becomes higher than that in the normal state. Then, when the rotation speed of the water pump 2b exceeds the third determination value, it is determined that the flow path is narrowed due to accumulation of scale in the first water refrigerant heat exchanger 4. it can. On the other hand, when the rotation speed of the water pump 2b is equal to or less than the third determination value, it is determined that the flow path is not narrowed due to accumulation of scale in the first water refrigerant heat exchanger 4. be able to.

  When it is not detected that the flow path is narrowed due to accumulation of scale in the first water-refrigerant heat exchanger 4, the controller 50 selects and executes the first heating operation. . On the other hand, when it is detected that the flow path is narrowed due to the accumulation of scale in the first water refrigerant heat exchanger 4, the control unit 50 sets the three-way valve 22 to the first state. Is switched to the second state, and the second heating operation is selected and executed. When it is detected that the flow path is narrowed during the execution of the first heating operation, the second heating operation may be immediately switched to, or the second heating operation being performed may be performed. The first heating operation may be continued as it is, and the second heating operation may be performed after the next time.

  In addition, the control unit 50 is provided in a user interface device (not shown) when detecting that the flow path is narrowed due to accumulation of scale in the first water-refrigerant heat exchanger 4. It is desirable to notify the user of the abnormality by displaying on the display unit or by emitting sound from a speaker provided in the user interface device. This can prompt the user to perform maintenance.

  In the present invention, the first heating operation and the second heating operation are not limited to the configuration in which the first heating operation and the second heating operation are automatically selected, and the first heating operation and the second heating operation are performed by manually switching the three-way valve 22. You may make it the structure which selects.

  In the present embodiment, the water refrigerant heat exchanger is divided into the first water refrigerant heat exchanger 4 and the second water refrigerant heat exchanger 5, and the first water refrigerant heat exchanger 4 and the second water refrigerant heat exchanger 4 are separated. The water refrigerant heat exchanger 5 is a separate body. For this reason, it is possible to replace only the first water refrigerant heat exchanger 4 without replacing the second water refrigerant heat exchanger 5. As described above, the amount of scale generated in the second water refrigerant heat exchanger 5 is extremely smaller than that of the first water refrigerant heat exchanger 4. For this reason, when the flow path is narrowed due to the accumulation of scale, it is not necessary to replace the second water refrigerant heat exchanger 5, and only the first water refrigerant heat exchanger 4 is replaced with a new or regenerated product. Thus, the narrowing of the flow path due to the accumulation of scales can be eliminated. Thus, in the heat pump water heater of this embodiment, when the scale accumulates inside the water refrigerant heat exchanger, there is no need to replace the entire water refrigerant heat exchanger, and the first water refrigerant heat exchanger 4 Can be dealt with by replacing only with new or refurbished products. For this reason, maintenance can be performed easily and at low cost. In addition, when replacing the 1st water refrigerant | coolant heat exchanger 4, what is necessary is just to remove the connection part of two places of refrigerant | coolant piping, and the connection part of two places of water piping.

  In the present embodiment, the first water refrigerant heat exchanger 4 is smaller than the second water refrigerant heat exchanger 5. Here, the first water refrigerant heat exchanger 4 is smaller than the second water refrigerant heat exchanger 5 when the volume of the space occupied by the first water refrigerant heat exchanger 4 is the second water. This means that the volume of the space occupied by the refrigerant heat exchanger 5 is smaller. In this embodiment, it is not necessary to replace the relatively large second water refrigerant heat exchanger 5, and it is only necessary to replace the relatively small first water refrigerant heat exchanger 4, so that maintenance is easier and less expensive. Can be done at a cost.

  In the present embodiment, the first water refrigerant heat exchanger 4 and the second water refrigerant heat exchanger 5 are arranged in separate chambers. As a result, when the first water refrigerant heat exchanger 4 is replaced, the second water refrigerant heat exchanger 5 does not interfere with the operation, so the operation of replacing the first water refrigerant heat exchanger 4 is performed. It can be done easily. In particular, the first water refrigerant heat exchanger 4 can be removed without removing the second water refrigerant heat exchanger 5.

  Moreover, in this embodiment, there exist the following advantages by having arrange | positioned the 1st water refrigerant | coolant heat exchanger 4 in the machine room 32 in which the compressor 3 is arrange | positioned. As a first advantage, since the first water refrigerant heat exchanger 4 can be disposed near the compressor 3, the refrigerant paths 10, 17 connecting the compressor 3 and the first water refrigerant heat exchanger 4 are provided. The distance can be shortened. Thereby, while being able to reduce the pressure loss of a refrigerant | coolant, since the heat dissipation loss from the refrigerant | coolant paths 10 and 17 can be reduced, performance can be improved. As a second advantage, when the first water refrigerant heat exchanger 4 is replaced, it is possible to adopt a configuration in which it is not necessary to remove other main equipment. Replacement work can be facilitated. On the other hand, if the second water refrigerant heat exchanger 5 disposed in the air passage chamber 33 is to be replaced, it is necessary to remove other equipment such as the blower 8. Replacing the refrigerant heat exchanger 5 requires a lot of work. Further, unlike the air passage chamber 33, since the outside air does not flow through the machine chamber 32, the first water refrigerant heat exchanger 4 is rigid like a storage case 34 that houses the second water refrigerant heat exchanger 5. There is no need to store it in a container. Therefore, as a third advantage, since it is not necessary to store the first water refrigerant heat exchanger 4 in a hard container, the replacement work of the first water refrigerant heat exchanger 4 can be facilitated.

  In the present embodiment, the second water refrigerant heat exchanger 5 is disposed in the air passage chamber 33 in which the evaporator 7 is disposed, so that the space of the air passage chamber 33 can be sufficiently increased. In order to improve the performance of the heat pump unit 1, it is important to make the evaporator 7 sufficiently large. To enlarge the evaporator 7, it is necessary to increase the space of the air passage chamber 33. In the present embodiment, by arranging the second water refrigerant heat exchanger 5 in the air passage chamber 33, the space of the air passage chamber 33 can be increased, and the performance of the heat pump unit 1 can be improved. On the other hand, if the second water-refrigerant heat exchanger 5 is disposed in the machine room 32, the second water-refrigerant heat exchanger 5 is a large-sized device, so that the machine room 32 needs to be enlarged. As a result, the air passage chamber 33 must be reduced. For this reason, there arises a disadvantage that the evaporator 7 cannot be enlarged. Further, since the second water refrigerant heat exchanger 5 does not need to be replaced, there is no inconvenience even if the second water refrigerant heat exchanger 5 is disposed at a place that is difficult to remove, such as under the blower 8 in the air passage chamber 33.

  In the present embodiment, the outlet water temperature of the second water refrigerant heat exchanger 5 during the first heating operation is preferably 80 ° C. or lower. The thick broken line in FIG. 6 shows an example of the amount of calcium carbonate contained in tap water. In the case of this example, when the water temperature is about 80 ° C. or less, the content of calcium carbonate is below solubility, so that calcium carbonate does not precipitate and scale does not occur. On the other hand, when the water temperature is about 80 ° C. or higher, the content of calcium carbonate exceeds the solubility, so that calcium carbonate is precipitated and scale is generated. In view of this, if the outlet water temperature of the second water refrigerant heat exchanger 5 at the time of the first heating operation is set to 80 ° C. or less, the scale is generated in the second water refrigerant heat exchanger 5. Therefore, the accumulation of scale can be reliably concentrated on the first water refrigerant heat exchanger 4 side.

  Moreover, in this embodiment, it is preferable that the outlet water temperature of the 2nd water refrigerant | coolant heat exchanger 5 at the time of a 1st heating operation is 65 degreeC or more. When the heat pump water heater has a function of variably controlling the target hot water temperature, the outlet water temperature of the second water refrigerant heat exchanger 5 when the target hot water temperature is set to the upper limit value is 65. It should just be above ℃. By setting the outlet water temperature of the second water refrigerant heat exchanger 5 to 65 ° C. or higher, the first water refrigerant heat exchange is performed as compared with the case where the outlet water temperature of the second water refrigerant heat exchanger 5 is lower than 65 ° C. Since the heating capacity required for the vessel 4 is reduced, the first water refrigerant heat exchanger 4 can be downsized. For this reason, replacement of the first water refrigerant heat exchanger 4 can be easily performed at low cost. Moreover, since the 1st water refrigerant heat exchanger 4 can be reduced in size, the machine room 32 can be made small and the air channel room 33 can be enlarged. Thereby, the evaporator 7 can be enlarged and the performance of the heat pump unit 1 can be improved. In addition, since the temperature of hot water stored in the hot water storage tank 2a of the tank unit 2 is often required to be a temperature of 65 ° C. or higher, in general, the temperature of the discharged water of the heat pump unit 1 may be required to be 65 ° C. or higher. Many. If the outlet water temperature of the second water-refrigerant heat exchanger 5 during the first heating operation is 65 ° C. or higher, the scale accumulates in the first water-refrigerant heat exchanger 4 and the second heating operation is performed. Even if it comes to doing, the hot water temperature of the heat pump unit 1 can be reliably made 65 degreeC or more, and a required hot water temperature can be ensured.

  In the present embodiment, the heating capacity [W] of the first water refrigerant heat exchanger 4 and the heating capacity [W] of the second water refrigerant heat exchanger 5 are totaled during the first heating operation. It is preferable that the ratio of the heating capacity of the first water-refrigerant heat exchanger 4 to the heated capacity is 12 to 18%. By setting the ratio between the heating capacity of the first water refrigerant heat exchanger 4 and the heating capacity of the second water refrigerant heat exchanger 5 during the first heating operation as described above, the first heating operation is performed. Since the outlet water temperature of the second water-refrigerant heat exchanger 5 at the time can be set in a range of approximately 65 ° C. to 80 ° C., the same effect as described above can be obtained. In addition, since the first water refrigerant heat exchanger 4 can be sufficiently downsized relative to the second water refrigerant heat exchanger 5, the replacement of the first water refrigerant heat exchanger 4 can be performed at a lower cost and more easily. be able to. Moreover, since the machine chamber 32 can be made smaller and the air passage chamber 33 can be made larger, the evaporator 7 can be made larger and the performance of the heat pump unit 1 can be further improved.

  FIG. 7 is a diagram showing the relationship between the dimensionless flow path length of the water refrigerant heat exchanger and the water temperature in the water refrigerant heat exchanger. The horizontal axis in FIG. 7 represents the water flow length (or refrigerant flow length) in the water-refrigerant heat exchanger in a dimensionless manner, and the origin (0.0) of the horizontal axis represents water. The inlet and the refrigerant outlet are shown, and the right end (1.0) of the horizontal axis shows the hot water outlet and the refrigerant inlet. FIG. 7 shows a case where the water temperature at the inlet of the water refrigerant heat exchanger is 9 ° C. and the water temperature at the outlet of the water refrigerant heat exchanger is 90 ° C. In this case, as can be seen from FIG. 7, the water temperature is approximately 65 ° C. at the position of the dimensionless flow path length 0.8, and the water temperature is approximately 80 ° C. at the position of the dimensionless flow path length 0.95.

  During the first heating operation of the heat pump unit 1 of the present embodiment, the origin (0.0) of the horizontal axis in FIG. 7 corresponds to the water inlet and the refrigerant outlet of the second water refrigerant heat exchanger 5, The right end (1.0) of the shaft corresponds to the hot water outlet and the refrigerant inlet of the first water refrigerant heat exchanger 4. The structure of the heat transfer section of the first water refrigerant heat exchanger 4 and the structure of the heat transfer section of the second water refrigerant heat exchanger 5 are the same, and the water in the first water refrigerant heat exchanger 4 is the same. When the flow path length (or the flow path length of the refrigerant) and the flow path length of the water in the second water-refrigerant heat exchanger 5 (or the flow path length of the refrigerant) are different, from FIG. The ratio of the channel length in the first water refrigerant heat exchanger 4 to the channel length in the second water refrigerant heat exchanger 5 is set to 0.2: 0.8 to 0.05: 0.95. By doing, it turns out that the outlet water temperature of the 2nd water-refrigerant heat exchanger 5 at the time of a 1st heating operation becomes the range of 65 to 80 degreeC in general.

  From the above, in the present embodiment, the structure of the heat transfer section of the first water refrigerant heat exchanger 4 and the structure of the heat transfer section of the second water refrigerant heat exchanger 5 are the same, and the first Configuration in which the water flow path length (or refrigerant flow path length) in the water-refrigerant heat exchanger 4 and the water flow path length (or refrigerant flow path length) in the second water-refrigerant heat exchanger 5 are different. In this case, the ratio of the channel length in the first water refrigerant heat exchanger 4 to the channel length in the second water refrigerant heat exchanger 5 is set to 0.2: 0.8 to 0.8. 05: 0.95 is preferable. Thereby, since the exit water temperature of the 2nd water refrigerant | coolant heat exchanger 5 at the time of a 1st heating operation can be made into the range of 65 to 80 degreeC in general, the same effect as the above is acquired. In this case, the flow path length in the first water refrigerant heat exchanger 4 is equal to the flow path length in the first water refrigerant heat exchanger 4 and the flow path length in the second water refrigerant heat exchanger 5. Since it is only 5 to 20% of the total, the first water refrigerant heat exchanger 4 can be sufficiently downsized relative to the second water refrigerant heat exchanger 5. For this reason, the replacement of the first water refrigerant heat exchanger 4 can be easily performed at lower cost. Moreover, since the machine chamber 32 can be made smaller and the air passage chamber 33 can be made larger, the evaporator 7 can be made larger and the performance of the heat pump unit 1 can be further improved.

  Even if the structure of the heat transfer section of the first water refrigerant heat exchanger 4 and the structure of the heat transfer section of the second water refrigerant heat exchanger 5 are not the same, the first water refrigerant heat exchange is performed. The ratio of the total heat transfer area of the vessel 4 and the total heat transfer area of the second water-refrigerant heat exchanger 5 is set to 0.2: 0.8 to 0.05: 0.95 in the same manner as described above. The effect is obtained. For this reason, in this embodiment, the ratio of the total heat transfer area of the 1st water refrigerant heat exchanger 4 and the total heat transfer area of the 2nd water refrigerant heat exchanger 5 is 0.2: 0.8- 0.05: 0.95 is preferable.

  When the second heating operation is performed, the control unit 50 preferably performs control so that the tapping temperature is lower than when the first heating operation is performed. For example, when the second heating operation is performed, the control unit 50 sets the target hot water temperature to a lower value (for example, 65 °) than the target hot water temperature (for example, 90 ° C.) when the first heating operation is performed. ℃). Thus, when carrying out the second heating operation, the precipitation of calcium can be suppressed by lowering the tapping temperature, so that the scale adheres in the second water refrigerant heat exchanger 5. Can be reliably suppressed.

  In addition, the control unit 50 performs a water pump so that the flow rate of the hot water supplied to the tank unit 2 is larger when the second heating operation is performed than when the first heating operation is performed. It is preferable to control the rotation speed of 2b. Thus, when performing the 2nd heating operation, since the tapping temperature falls by enlarging the flow volume of the hot water supplied to the tank unit 2, precipitation of calcium can be suppressed. As a result, it is possible to reliably suppress the scale from adhering to the second water refrigerant heat exchanger 5.

  Further, when the controller 50 performs the second heating operation, the temperature of the refrigerant discharged from the first discharge port 3e of the compressor 3 is higher than that when the first heating operation is performed. It is preferable to control so that it may become low. The control unit 50 can control the temperature of the refrigerant discharged from the first discharge port 3 e of the compressor 3 by controlling the expansion valve 6. If the temperature of the refrigerant discharged from the first discharge port 3e of the compressor 3 is high, water heated by the refrigerant may become locally or temporarily at a high temperature, and calcium may precipitate. Therefore, when performing the second heating operation, by lowering the temperature of the refrigerant discharged from the first discharge port 3e of the compressor 3 as compared with the case of performing the first heating operation, Since it is suppressed that the water heated by the refrigerant becomes high temperature locally or temporarily, precipitation of calcium can be suppressed more reliably. As a result, it is possible to reliably suppress the scale from adhering to the second water refrigerant heat exchanger 5.

  In addition, when the second heating operation is performed, the control unit 50 preferably performs control so that the capacity of the compressor 3 is lower than that in the case where the first heating operation is performed. In the present embodiment, the control unit 50 can control the capacity of the compressor 3 by controlling the rotation speed of the compressor 3. Generally, in a refrigeration cycle, if the radiator is small, the high-pressure side refrigerant pressure tends to increase. In the second heating operation, only the second water-refrigerant heat exchanger 5 functions as a radiator, so that the radiator is smaller than that in the first heating operation. For this reason, when the second heating operation is performed, it is ensured that the high-pressure side refrigerant pressure becomes too high by lowering the capacity of the compressor 3 as compared with the case where the first heating operation is performed. It is preferable to suppress.

Embodiment 2. FIG.
Next, the second embodiment of the present invention will be described with reference to FIG. 8. 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. Is omitted. FIG. 8 is a diagram schematically illustrating the configuration of the refrigerant circuit and the water flow path provided in the heat pump unit 1 of the heat pump water heater according to the second embodiment of the present invention.

  As shown in FIG. 8, the heat pump unit 1 according to the second embodiment includes an on-off valve 28 as a flow path switching unit instead of the three-way valve 22 according to the first embodiment. The on-off valve 28 is provided in the bypass water flow path 27. The on-off valve 28 can be switched between a state in which the bypass water passage 27 is closed and a state in which the bypass water passage 27 is opened. The water channel 24 and the main water channel 25 are always in communication. A bypass water flow path 27 is branched from a connection portion between the water flow path 24 and the main water flow path 25.

  When performing the first heating operation, the on-off valve 28 is closed. Thereby, at the time of the 1st heating operation, the water which flowed in from the water inlet 1a flows into the 2nd water refrigerant heat exchanger 5 through the water flow path 23, and inside the 2nd water refrigerant heat exchanger 5, Heated by heat. The hot water generated by being heated in the second water refrigerant heat exchanger 5 flows into the first water refrigerant heat exchanger 4 through the water flow path 24 and the main water flow path 25, and the first water refrigerant. In the heat exchanger 4, it is further heated by the heat of the refrigerant. Hot water that has been heated further by being further heated in the first water refrigerant heat exchanger 4 reaches the outlet 1b through the water flow path 26, and is supplied to the tank unit 2 through the water pipe 12. . As described above, the first heating operation of the second embodiment is the same as the first heating operation of the first embodiment.

  When performing the second heating operation, the on-off valve 28 is opened. As shown in FIG. 8, during the second heating operation, the water flowing in from the water inlet 1 a flows into the second water refrigerant heat exchanger 5 through the water flow path 23, and the second water refrigerant heat exchanger 5. It is heated by the heat of the refrigerant. The hot water generated by being heated in the second water refrigerant heat exchanger 5 flows from the water flow path 24 through the main water flow path 25 into the first water refrigerant heat exchanger 4, and the water flow path 24. To the flow into the bypass water flow path 27. And the hot water that has passed through the first water refrigerant heat exchanger 4 and the hot water that has passed through the bypass water flow path 27 without passing through the first water refrigerant heat exchanger 4 are merged in the water flow path 26, and the outlet 1b. To the tank unit 2 through the water pipe 12.

In the second embodiment, when the scale is accumulated in the first water refrigerant heat exchanger 4 and the pressure loss becomes excessive, the second water operation is selected to select the second water since it is possible to flow through the hot water governor bypass water flow path 27 passing through the refrigerant heat exchanger 5, it can be greater the pressure loss of the first water-refrigerant heat exchanger 4 performs smoothly operating . In the present embodiment, since the on-off valve 28 having a simpler structure and lower cost than the three-way valve 22 can be used, the cost can be reduced.

  On the other hand, in the first embodiment, during the second heating operation, the entire amount of hot water that has passed through the second water refrigerant heat exchanger 5 is caused to flow through the bypass water flow path 27 and passes through the first water refrigerant heat exchanger 4. The amount of hot water can be reduced to zero. For this reason, since the first embodiment can accurately predict the state during the second heating operation as compared with the second embodiment, the second heating operation can be controlled more easily. it can.

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment. For example, in the above-described embodiment, the case where the compressor 3 including the first suction port 3d, the first discharge port 3e, the second suction port 3f, and the second discharge port 3g is used is described as an example. However, the present invention uses a compressor having one intake port and one discharge port, and the second water refrigerant heat exchange is performed without the refrigerant passing through the first water refrigerant heat exchanger 4 passing through the compressor. The present invention is also applicable to a refrigerant circuit configured to be sent to the vessel 5. Moreover, you may comprise so that a refrigerant circuit may be switched so that a refrigerant | coolant may flow through the 1st water refrigerant | coolant heat exchanger 4 at the time of a 2nd heating operation.

1 heat pump unit, 1a water inlet, 1b hot water outlet,
2 tank unit, 2a hot water storage tank, 2b water pump, 2c hot water mixing valve,
3 Compressor, 3a Airtight container, 3b Compression element, 3c Electric element, 3d First suction port,
3e 1st discharge port, 3f 2nd suction port, 3g 2nd discharge port,
4 first water refrigerant heat exchanger, 5 second water refrigerant heat exchanger, 6 expansion valve, 7 evaporator,
8 Blowers, 9 High / low pressure heat exchangers, 11, 12 Water piping, 13 Water supply piping,
14 hot water supply pipe, 15 water supply branch pipe, 16 hot water supply pipe,
10, 17, 18, 19, 20, 21 refrigerant path, 22 three-way valve,
23, 24, 26 Water channel, 25 Main water channel, 27 Bypass water channel,
28 On-off valve, 30 housing, 31 partition member, 32 machine room, 33 air channel room,
34 storage case, 50 control unit

Claims (18)

A compressor for compressing the refrigerant;
A first water-refrigerant heat exchanger that performs heat exchange between the refrigerant and water;
A second water refrigerant heat exchanger for exchanging heat between the refrigerant and water;
Supplying the refrigerant compressed by the compressor to the first water refrigerant heat exchanger and passing the refrigerant after passing through the first water refrigerant heat exchanger to the second water refrigerant heat exchanger A refrigerant path capable of forming a refrigerant circuit to be supplied; and
A water flow path including a main water flow path for sending hot water that has passed through the second water refrigerant heat exchanger to the first water refrigerant heat exchanger, and a bypass water flow path that bypasses the first water refrigerant heat exchanger. When,
Channel switching means capable of switching between a state of closing the bypass water channel and a state of opening the bypass water channel;
With
With the bypass water flow path closed, hot water heated by the second water refrigerant heat exchanger is sent to the first water refrigerant heat exchanger via the main water flow path, and the first water A first heating operation for supplying hot water further heated by the refrigerant heat exchanger to the downstream side of the water flow path;
With the bypass water flow path open, supply the entire amount of hot water heated by the second water refrigerant heat exchanger to the downstream side via the bypass water flow path, or the second water Hot water heated by the refrigerant heat exchanger is caused to flow into both the bypass water channel and the main water channel, and the hot water that has passed through the bypass water channel and the hot water that has passed through the first water refrigerant heat exchanger are A second heating operation that joins and supplies the downstream side,
Executable der the is,
Detecting means capable of detecting that the flow path is narrowed by precipitates deposited from hot water in the first water-refrigerant heat exchanger;
When it is not detected that the flow path is narrowed, the first heating operation is selected, and when it is detected that the flow path is narrowed, the second heating is performed. the heat pump water heater which Ru and selecting means for selecting the operation. A compressor for compressing the refrigerant;
A first water-refrigerant heat exchanger that performs heat exchange between the refrigerant and water;
A second water refrigerant heat exchanger for exchanging heat between the refrigerant and water;
Supplying the refrigerant compressed by the compressor to the first water refrigerant heat exchanger and passing the refrigerant after passing through the first water refrigerant heat exchanger to the second water refrigerant heat exchanger A refrigerant path capable of forming a refrigerant circuit to be supplied; and
A water flow path including a main water flow path for sending hot water that has passed through the second water refrigerant heat exchanger to the first water refrigerant heat exchanger, and a bypass water flow path that bypasses the first water refrigerant heat exchanger. When,
Channel switching means capable of switching between a state of closing the bypass water channel and a state of opening the bypass water channel;
With
With the bypass water flow path closed, hot water heated by the second water refrigerant heat exchanger is sent to the first water refrigerant heat exchanger via the main water flow path, and the first water A first heating operation for supplying hot water further heated by the refrigerant heat exchanger to the downstream side of the water flow path;
With the bypass water flow path open, supply the entire amount of hot water heated by the second water refrigerant heat exchanger to the downstream side via the bypass water flow path, or the second water Hot water heated by the refrigerant heat exchanger is caused to flow into both the bypass water channel and the main water channel, and the hot water that has passed through the bypass water channel and the hot water that has passed through the first water refrigerant heat exchanger are A second heating operation that joins and supplies the downstream side,
Is possible and
The compressor includes a first suction port for sucking the refrigerant, a first discharge port for discharging the refrigerant sucked from the first suction port, and a second suction port for sucking the refrigerant. And a second discharge port for discharging the refrigerant sucked from the second suction port,
The refrigerant path includes a path for guiding the refrigerant discharged from the first discharge port to the first water-refrigerant heat exchanger, and the refrigerant passing through the first water-refrigerant heat exchanger as the second. A heat pump water heater including a path leading to the suction port and a path leading the refrigerant discharged from the second discharge port to the second water refrigerant heat exchanger .   The hot water supply temperature control means which lowers the temperature of the hot water supplied to the said downstream side by the said 2nd heating operation compared with the temperature of the hot water supplied to the said downstream by the said 1st heating operation is provided. The heat pump water heater described.   The flow rate control means which enlarges the flow volume of the hot water supplied to the said downstream by the said 2nd heating operation compared with the flow volume of the hot water supplied to the said downstream by the said 1st heating operation is provided. Heat pump water heater.   Refrigerant discharge temperature control means is provided for lowering the temperature of the refrigerant discharged from the compressor in the second heating operation as compared with the temperature of the refrigerant discharged from the compressor in the first heating operation. The heat pump water heater according to any one of claims 1 to 4.   The compression function force control means for lowering the capacity of the compressor in the second heating operation as compared with the capacity of the compressor in the first heating operation. The heat pump water heater described. The channel switching means can be switched between a state in which the main water channel is opened and the bypass water channel is closed, and a state in which the main water channel is closed and the bypass water channel is opened,
In the second heating operation, with the main water flow path closed and the bypass water flow path opened, the total amount of hot water heated by the second water refrigerant heat exchanger is passed through the bypass water flow path. The heat pump water heater according to any one of claims 1 to 6, which is supplied to the downstream side. The compressor has a compression element that compresses the refrigerant in an airtight container, and an electric element that drives the compression element,
The refrigerant sucked from the first suction port is discharged from the first discharge port after being compressed by the compression element,
The heat pump water heater according to claim 2 , wherein the refrigerant that has been sucked into the second suction port is discharged from the second discharge port after cooling the electric element. The heat pump water heater according to any one of claims 1 to 8 , wherein an outlet water temperature of the second water-refrigerant heat exchanger during the first heating operation is 80 ° C or lower. The heat pump water heater according to any one of claims 1 to 9 , wherein an outlet water temperature of the second water-refrigerant heat exchanger during the first heating operation is 65 ° C or higher. The first water refrigerant heat exchanger has a heating capacity that is the sum of the heating capacity of the first water refrigerant heat exchanger and the heating capacity of the second water refrigerant heat exchanger during the first heating operation. The heat pump water heater according to any one of claims 1 to 10 , wherein a ratio of the heating capacity is 12 to 18%. The first water refrigerant heat exchanger and the second water refrigerant heat exchanger have the same structure and different channel lengths.
The ratio of the channel length of the first water refrigerant heat exchanger to the channel length of the second water refrigerant heat exchanger is 0.2: 0.8 to 0.05: 0.95. Item 12. The heat pump water heater according to any one of Items 1 to 11 . The ratio of the total heat transfer area of the first water refrigerant heat exchanger to the total heat transfer area of the second water refrigerant heat exchanger is 0.2: 0.8 to 0.05: 0.95. The heat pump water heater according to any one of claims 1 to 11 . The heat pump water heater according to any one of claims 1 to 13 , wherein the first water refrigerant heat exchanger is smaller than the second water refrigerant heat exchanger. The heat pump hot water supply according to any one of claims 1 to 14 , comprising a plurality of chambers, wherein the first water refrigerant heat exchanger and the second water refrigerant heat exchanger are arranged in separate chambers. Machine. The heat pump water heater according to any one of claims 1 to 15 , wherein the first water refrigerant heat exchanger is disposed inside a chamber in which the compressor is disposed. The heat pump water heater according to any one of claims 1 to 16 , wherein the second water refrigerant heat exchanger is disposed inside a chamber in which an evaporator for evaporating the refrigerant is disposed. The heat pump water heater according to any one of claims 1 to 17 , wherein a pressure on a high-pressure side of the refrigerant exceeds a critical pressure.

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