JP6660737B2 - Hot water supply system - Google Patents

Description

  The technology disclosed in this specification relates to a hot water supply system.

  Patent Document 1 discloses a hot water supply system. The hot water supply system includes a heat pump for heating water, a tank for storing water, a first circulation forward path for sending water from the heat pump to the tank, a first circulation return path for sending water from the tank to the heat pump, and supplying water to the tank. A water supply channel, a hot water supply channel for supplying hot water from the tank, a hot water return route branching off from the hot water supply channel and joining the water supply channel, a bypass waterway branching off from the hot water supply route and joining the hot water supply route, a heat pump, A first circulation device capable of executing a first circulation operation for circulating water in the order of a first circulation outward path, a tank, and a first circulation return path, and a second circulation apparatus for circulating water in the order of a tank, a hot water supply path, a return water path, and a water supply path. A second circulation device capable of performing a circulation operation is provided.

JP 2015-75270 A

  In the hot water supply system of Patent Document 1, by performing the second circulation operation, high-temperature water supplied from the upper portion of the tank is circulated to the hot-water supply path, and the high-temperature water is quickly supplied when the hot-water tap is opened. The hot water supply function has been realized. However, with such a configuration, in the second circulation operation, high-temperature water is returned to the lower part of the tank via the hot water return path. If hot water is returned to the lower part of the tank, the temperature stratification in the tank will be disturbed. If the temperature stratification in the tank is disturbed, the temperature of water sent from the lower part of the tank to the heat pump increases, and the COP of the heat pump decreases. In addition, if the temperature stratification in the tank is disturbed, the temperature of the water sent from the upper part of the tank to the hot water supply path will decrease. A technology capable of realizing a hot water function without disturbing the temperature stratification in the tank is expected.

  The present specification provides a technique for solving the above problem. The present specification provides a technology capable of realizing a quick hot water function in a hot water supply system including a heat pump and a tank without disturbing the temperature stratification in the tank.

  This specification discloses a hot water supply system. The hot water supply system includes a heat pump for heating water, a tank for storing water, a first circulation forward path for sending water from the heat pump to the tank, a first circulation return path for sending water from the tank to the heat pump, and supplying water to the tank. A water supply channel, a hot water supply channel for supplying hot water from the tank, a bypass water channel that branches off from the water supply channel and joins the hot water supply channel, and a hot water supply that branches off from the first circulation outward route and is located downstream of the junction of the bypass water channel. A second circulation forward path that merges with the path, a second circulation return path that branches off from the hot water supply path downstream of the junction of the second circulation forward path and merges with the first circulation return path, a heat pump, a first circulation forward path, and a tank A first circulation operation for circulating water in the order of the first circulation return path, and a second circulation for circulating water in the order of the heat pump, the first circulation forward path, the second circulation forward path, the hot water supply path, the second circulation return path, and the first circulation return path. Operation can be performed It has a Do circulation device.

  In the above hot water supply system, the circulation device performs the first circulation operation, and the heat pump heats the water, so that the water in the tank can be circulated and heated by the heat pump. In the above hot water supply system, the circulation device performs the second circulation operation, and the heat pump heats the water, so that high-temperature water can be circulated through the hot water supply path in preparation for the subsequent hot water supply. At this time, in the above hot water supply system, high temperature water circulating in the hot water supply path does not flow into the lower part of the tank, so that the temperature stratification in the tank is not disturbed. According to the above hot water supply system, the quick hot water function can be realized without disturbing the temperature stratification in the tank.

The above hot water supply system comprises a first heating operation for heating water with a heat pump while performing a first circulation operation with a circulation device, and a second heating operation for heating water with a heat pump while performing a second circulation operation with a circulation device. Is executable. The above-described hot water supply system further includes a temperature detection unit that detects a temperature of the water flowing in the hot water supply path upstream of the junction of the second circulation outward path, and during execution of the second heating operation, the temperature of the hot water supply path is increased. When the hot water supply is started, if the temperature detected by the temperature detecting means is lower than the predetermined temperature, the second heating operation is continued as it is, and if the temperature detected by the temperature detecting means is equal to or higher than the predetermined temperature, The operation is switched from the second heating operation to the first heating operation.

According to the above hot water supply system, the first heating operation for circulating and heating the water in the tank by the heat pump and the second heating operation for circulating high-temperature water through the hot water supply path in preparation for the subsequent hot water supply can be executed. it can.

In the above hot water supply system, the circulation pump is provided with the circulation device in the first circulation return path upstream of the branch point of the second circulation return path or the first circulation return path downstream of the junction of the second circulation return path. Can be provided.

According to the above hot water supply system, the first circulation operation in which water is circulated in the order of the heat pump, the first circulation outward path, the tank, and the first circulation return path using a single circulation pump, the heat pump, the first circulation outward path, Both the second circulation operation for circulating water in the order of the two circulation forward path, the hot water supply path, the second circulation return path, and the first circulation return path can be executed. By reducing the number of circulation pumps, it is possible to reduce costs associated with manufacturing the hot water supply system.

  The above hot water supply system can be configured such that the target boiling temperature of the heat pump during the second heating operation is lower than the target boiling temperature of the heat pump during the first heating operation.

  Normally, when hot water is supplied from the tank, the hot water is supplied at a set hot water supply temperature by mixing low-temperature water from the water supply with high-temperature water from the tank. Therefore, the target boiling temperature in the first heating operation is set higher than the hot water supply set temperature. On the other hand, it is preferable that the target boiling temperature in the second heating operation is a temperature close to the hot water supply set temperature. As described above, by setting the target boiling temperature of the heat pump in the second heating operation to be lower than the target boiling temperature of the heat pump in the first heating operation, energy consumption in the second heating operation is reduced. can do.

  The above hot water supply system can be configured such that the first heating operation and the second heating operation can be continuously performed without stopping the heat pump.

  When the heat pump is driven from a stopped state, it takes time for the state of the refrigerant to stabilize. Therefore, it takes some time until the water can be heated at the target boiling temperature. For this reason, if the heat pump is stopped and restarted each time when the first heating operation and the second heating operation are executed, it takes time for the boiling temperature of the heat pump to stabilize. According to the above hot water supply system, the first heating operation and the second heating operation are continuously performed without stopping the heat pump, so that the boiling temperature of the heat pump can be quickly stabilized. In the above hot water supply system, the second heating operation may be performed immediately after the first heating operation, or the first heating operation may be performed immediately after the second heating operation.

It is a figure showing typically composition of hot water supply system 2 concerning an example. It is a figure explaining tank heating operation in hot water supply system 2 concerning an example. It is a figure explaining hot water circulation operation in hot water supply system 2 concerning an example. It is a figure explaining switching from hot water circulation operation to hot water supply operation in hot water supply system 2 concerning an example. It is a figure explaining the hot-water supply operation in the hot-water supply system 2 which concerns on an Example. It is a figure explaining the hot-water supply driving | operation in case the long time has passed since the last hot-water supply in the hot-water supply system 2 which concerns on an Example.

(Example)
As shown in FIG. 1, the hot water supply system 2 according to the present embodiment includes a heat pump unit 4, a tank unit 6, a hot water circulation unit 8, and a control unit 100.

The heat pump unit 4 includes a heat pump 10 and a circulation pump 12. The heat pump 10 includes a refrigerant circulation path 14 for circulating a refrigerant (for example, an HFC refrigerant such as R410A or a CO ₂ refrigerant such as R744), a compressor 16, a condenser 18, an expansion valve 20, an evaporator 22, A fan 24 is provided. The compressor 16 pressurizes and sends out the refrigerant in the gaseous state. The condenser 18 has a coolant channel 18a and a water channel 18b. The condenser 18 causes heat exchange between the refrigerant flowing through the refrigerant flow path 18a and the water flowing through the water flow path 18b. The expansion valve 20 adiabatically expands the refrigerant in the liquid phase to reduce the pressure. The evaporator 22 exchanges heat between the refrigerant flowing inside and the outside air blown by the fan 24.

  In the heat pump 10, a high-temperature and high-pressure gas-phase refrigerant sent from the compressor 16 flows into the condenser 18. When the refrigerant passes through the refrigerant channel 18a of the condenser 18, it radiates heat to the water flowing through the water channel 18b and condenses to be in a liquid phase. The refrigerant in the liquid phase that has passed through the condenser 18 is depressurized by the expansion valve 20. The low-temperature and low-pressure liquid-phase refrigerant that has passed through the expansion valve 20 flows into the evaporator 22. When passing through the evaporator 22, the refrigerant absorbs heat from the outside air and evaporates, so that it enters a gaseous state. The refrigerant in a gaseous state that has passed through the evaporator 22 is returned to the compressor 16. That is, the heat pump 10 operates as a heat source device that absorbs heat from outside air by the evaporator 22 and heats water by the condenser 18.

  A first circulation forward path 26 is connected to the condenser 18 on the downstream side of the water flow path 18b. A first circulation return path 28 is connected to the condenser 18 on the upstream side of the water flow path 18b. The circulation pump 12 is provided in the first circulation return path 28. The thermistor 30 is provided in the first circulation outward path 26. In the heat pump unit 4, the water can be heated by driving the heat pump 10 and driving the circulation pump 12. In this case, by driving the circulation pump 12, water is sent from the first circulation return path 28 to the water flow path 18b, and water heated through the water flow path 18b is sent to the first circulation outward path 26. In the heat pump unit 4, the compressor 16, the expansion valve 20, and the fan 24 are set such that the temperature of the water (hereinafter, also referred to as the boiling temperature) sent from the water flow path 18 b to the first circulation forward path 26 becomes the target boiling temperature. And other operations are controlled. The temperature of the water sent from the water flow path 18b to the first circulation outward path 26 is detected by the thermistor 30.

  The tank unit 6 includes a tank 32, a low-temperature-side flow control valve 34, and a high-temperature-side flow control valve 36. The tank 32 is a closed type, and the outside is covered with a heat insulating material. Inside the tank 32, water is stored until it is full. In the tank 32, thermistors 32a, 32b, 32c and 32d are arranged at predetermined intervals in the height direction of the tank 32. Each of the thermistors 32a, 32b, 32c, and 32d measures the temperature of water in the tank 32 at the mounting position. The heat storage state of the tank 32 can be specified from the detected temperatures of the thermistors 32a, 32b, 32c, and 32d.

  The first circulation return path 28 is connected to the bottom of the tank 32. The first circulation outward path 26 is connected to the top of the tank 32. When the circulation pump 12 of the heat pump unit 4 is driven, water is sent from the lower part of the tank 32 to the water flow path 18b of the condenser 18 via the first circulation return path 28, and from the water flow path 18b via the first circulation outward path 26. Water is sent to the upper part of the tank 32. When the heat pump 10 and the circulation pump 12 are driven in the heat pump unit 4, the water at the lower part of the tank 32 is heated by the condenser 18 and returned to the upper part of the tank 32. Inside the tank 32, a temperature stratification is formed in which a high-temperature water layer is stacked on a low-temperature water layer.

  A water supply channel 38 is connected to the bottom of the tank 32. The water supply channel 38 supplies water from the water supply to the tank 32. A hot water supply path 40 is connected to the top of the tank 32. The hot water supply path 40 supplies water from the tank 32 to a hot water tap 42 such as a kitchen or a washroom. A bypass water passage 44 is connected to the water supply passage 38 and the hot water supply passage 40. The bypass water passage 44 branches off from the water supply passage 38 and joins the hot water supply passage 40. The bypass water passage 44 is provided with a low-temperature side flow meter 46 for detecting the flow amount of water flowing through the bypass water passage 44 and a low-temperature side flow control valve 34 for adjusting the flow amount of water flowing through the bypass water passage 44. A hot water flow meter 48 for detecting the flow rate of water sent from the tank 32 to the hot water supply passage 40 is provided in the hot water supply passage 40 upstream (to the tank 32 side) of the junction of the bypass water passage 44, and a hot water supply passage 40 from the tank 32. A high-temperature-side flow control valve 36 that controls the flow rate of water sent to the air conditioner is provided. A thermistor 50 that detects the temperature of water supplied from the tank unit 6 to the hot water supply tap 42 is provided in the hot water supply path 40 downstream (on the hot water tap 42 side) of the junction of the bypass water flow path 44.

  When the hot water tap 42 is opened, low-temperature water is sent from the water supply channel 38 to the lower portion of the tank 32, and high-temperature water is sent from the upper portion of the tank 32 to the hot water channel 40. Further, low-temperature water is sent from the water supply channel 38 to the hot water supply channel 40 via the bypass water channel 44. In the hot water supply channel 40, high-temperature water from the tank 32 and low-temperature water from the bypass water channel 44 are mixed, and the mixed water is sent to the hot water tap 42. The tank unit 6 adjusts the opening degree of the low-temperature side flow control valve 34 and the opening degree of the high-temperature side flow control valve 36 so that the temperature detected by the thermistor 50 becomes a preset hot water supply setting temperature. The low-temperature side flow control valve 34 and the high-temperature side flow control valve 36 operate as a mixer that mixes high-temperature water from the tank 32 and low-temperature water from the bypass water passage 44 to adjust the temperature to the hot water supply set temperature.

  The hot water circulation unit 8 includes a first three-way valve 52, a second three-way valve 54, and a check valve 56. The first three-way valve 52 is interposed in the first circulation outward path 26. The second circulation outward path 58 is connected to the first three-way valve 52. The second circulation outgoing path 58 branches off from the first circulation outgoing path 26 and joins the hot water supply path 40 downstream (on the hot water tap 42 side) from the junction of the bypass water path 44. The first three-way valve 52 is in a state where the water sent from the water passage 18b of the condenser 18 to the first circulation outgoing passage 26 is sent to the tank 32, and the water is sent from the water passage 18b of the condenser 18 to the first circulation outgoing passage 26. The state is switched between the state in which the drained water is sent to the second circulation outward path 58. The second three-way valve 54 is interposed in the first circulation return path 28 on the upstream side of the circulation pump 12 (on the tank 32 side). The second circulation return path 60 is connected to the second three-way valve 54. The second circulation return path 60 branches off from the hot water supply path 40 downstream (on the hot water tap 42 side) of the junction of the second circulation outward path 58 and joins the first circulation return path 28. The second three-way valve 54 is in a state where the water from the tank 32 is sent to the water flow path 18b of the condenser 18 via the first circulation return path 28, and the water from the second circulation return path 60 is connected via the first circulation return path 28. The state is switched between the state of being sent to the water flow path 18b of the condenser 18. The check valve 56 is provided in the second circulation return path 60. The check valve 56 prohibits water from flowing from the first circulation return path 28 to the second circulation return path 60.

  The control unit 100 includes a CPU, a ROM, a RAM, and the like. Various operation programs are stored in the ROM. The RAM temporarily stores various signals input from the respective components of the heat pump unit 4, the tank unit 6, and the hot water circulation unit 8 to the control unit 100, and various data generated in the course of executing processing by the CPU. Is stored. The control unit 100 controls the operation of each component of the heat pump unit 4, the tank unit 6, and the hot water circulation unit 8 by the CPU executing a process based on information stored in the ROM or the RAM. Further, a remote controller (not shown) is connected to the control unit 100. The remote controller is provided with various switches for the user to operate the hot water supply system 2 and a liquid crystal display for displaying the operation state of the hot water supply system 2 to the user.

  Next, the operation of the hot water supply system 2 of the present embodiment will be described. Hereinafter, the tank heating operation, the hot water circulation operation, and the hot water supply operation performed by the hot water supply system 2 will be described.

(Tank heating operation)
The tank boiling operation is an operation in which the water in the tank 32 is heated by the heat pump unit 4 and the hot water is returned to the tank 32. In the hot water supply system 2 of the present embodiment, the control unit 100 stores the time of hot water supply to the hot water tap 42 and the actual result of the amount of hot water for a predetermined period (for example, one week) in the past. The control unit 100 estimates the hot water supply time and the amount of hot water on that day, which are estimated from past hot water supply results, at a predetermined time (for example, 2:00 am) every day. The start time of the tank boiling operation is set so that the amount of hot water exceeding the amount of hot water required for the operation is stored. Thereafter, when the set start time comes, the control unit 100 starts the tank heating operation. In the hot water supply system 2 of the present embodiment, the heat storage amount of the tank 32 is constantly monitored by the thermistors 32a, 32b, 32c, and 32d. Start raising operation.

  When the tank boiling operation is performed, the control unit 100 controls the first three-way valve 52 of the hot water circulation unit 8 so that the water sent from the water flow path 18b of the condenser 18 to the first circulation outgoing path 26 becomes the tank 32. And the second three-way valve 54 is switched to a state in which water from the tank 32 is sent to the water flow path 18b of the condenser 18 via the first circulation return path 28. Further, the control unit 100 drives the compressor 16 and the fan 24 of the heat pump unit 4 and also drives the circulation pump 12.

  As shown in FIG. 2, by driving the compressor 16, the refrigerant in the refrigerant circulation path 14 circulates in the order of the compressor 16, the condenser 18, the expansion valve 20, and the evaporator 22. In this case, the refrigerant in the refrigerant circulation path 14 passing through the condenser 18 is in a high-temperature and high-pressure gas state. Further, by driving the circulation pump 12, low-temperature water present in the lower part of the tank 32 is sent to the condenser 18 via the first circulation return path 28, and is heated by the heat of the refrigerant when passing through the condenser 18. The high-temperature water that has passed through the condenser 18 is sent to the upper portion of the tank 32 via the first circulation outward path 26. At this time, the control unit 100 controls the compressor 16, the fan 24, and the circulation pump 12 such that the temperature of the water after passing through the condenser 18 detected by the thermistor 30 becomes the set target boiling temperature. Control behavior. Thereby, high-temperature water is stored in the tank 32. In the hot water supply system 2 of the present embodiment, the target heating temperature in the tank heating operation is set to a temperature obtained by adding a predetermined temperature (for example, 5 ° C.) to the hot water supply setting temperature. When the inside of the tank 32 becomes full with high-temperature water, the control unit 100 ends the tank boiling operation.

(Immediate hot water circulation operation)
The hot water circulation operation is an operation in which high-temperature water is circulated through the hot water supply passage 40 in preparation for hot water supply to the hot water tap 42. In hot water supply system 2 of the present embodiment, control unit 100 executes the hot water circulation operation immediately before the hot water supply time of the day estimated from past hot water supply results (for example, 5 minutes before the estimated hot water supply time). . Alternatively, in hot water supply system 2 of the present embodiment, control unit 100 executes the hot water circulation operation immediately after the tank boiling operation performed before the hot water supply time of the day estimated from past hot water supply results. Alternatively, in the hot water supply system 2 of the present embodiment, the control unit 100 executes the hot water circulation operation immediately before performing the tank heating operation, in preparation for performing hot water supply during the execution of the tank heating operation. .

  When performing the hot water circulation operation, the control unit 100 controls the first three-way valve 52 of the hot water circulation unit 8 to switch the water sent from the water flow path 18b of the condenser 18 to the first circulation forward path 26 to the second circulation path 26. While switching to the state of being sent to the circulation forward path 58, the second three-way valve 54 is switched to the state where water from the second circulation return path 60 is sent to the water flow path 18 b of the condenser 18 via the first circulation return path 28. Further, the control unit 100 drives the compressor 16 and the fan 24 of the heat pump unit 4 and also drives the circulation pump 12.

  As shown in FIG. 3, by driving the compressor 16, the refrigerant in the refrigerant circulation path 14 circulates in the order of the compressor 16, the condenser 18, the expansion valve 20, and the evaporator 22. In this case, the refrigerant in the refrigerant circulation path 14 passing through the condenser 18 is in a high-temperature and high-pressure gas state. In addition, by driving the circulation pump 12, low-temperature water in the hot water supply path 40 is sent to the condenser 18 via the second circulation return path 60 and the first circulation return path 28, and when passing through the condenser 18, the heat of the refrigerant is reduced. The water that has been heated by the heat treatment and has passed through the condenser 18 and has become high temperature is sent to the hot water supply path 40 via the first circulation outward path 26 and the second circulation outward path 58. At this time, the control unit 100 controls the compressor 16, the fan 24, and the circulation pump 12 such that the temperature of the water after passing through the condenser 18 detected by the thermistor 30 becomes the set target boiling temperature. Control behavior. In the hot water supply system 2 of the present embodiment, the target boiling temperature in the hot water circulation operation is set to the hot water supply set temperature. Thereby, high-temperature water circulates in the hot water supply passage 40. Thereafter, when the hot water tap 42 is opened, high-temperature water can be quickly supplied to the hot water tap 42.

  In the hot water supply system 2 of the present embodiment, when the hot water circulation operation is continuously performed immediately after the tank heating operation, the heat pump 10 and the circulation pump 12 are not stopped, and the tank heating operation and the hot water circulation operation are stopped. It is possible to shift to operation. When the heat pump 10 is once stopped and restarted, it takes time until the state of the refrigerant is stabilized, so that it takes some time until the water can be heated at the target boiling temperature. By operating the heat pump 10 continuously without stopping as described above, the boiling temperature can be quickly stabilized in the hot water circulation operation performed after the tank heating operation. Further, in the hot water supply system 2 of this embodiment, when the tank heating operation is continuously performed immediately after the hot water circulation operation, the heat pump 10 and the circulation pump 12 are not stopped, and the tank is switched from the hot water circulation operation to the tank operation. The operation can be shifted to the boiling operation. By operating the heat pump 10 continuously without stopping it, the boiling temperature can be quickly stabilized in the tank boiling operation performed after the hot water circulation operation.

(Hot water supply operation)
The hot water supply operation is an operation for supplying water at a set hot water supply temperature to the hot water tap 42. Control unit 100 determines that hot water supply to hot water tap 42 has been started when the total of the flow rate detected by low-temperature side flow meter 46 and the flow rate detected by high-temperature side flow meter 48 exceeds a predetermined value. And perform the hot water supply operation.

(Operation when starting hot water supply operation while performing hot water circulation operation)
When the hot water supply operation is started during the execution of the hot water circulation operation, control unit 100 continues the hot water circulation operation as it is. In this case, as shown in FIG. 4, low-temperature water remaining in the hot water supply passage 40 upstream (toward the tank 32) from the junction of the second circulation outward passage 58 and the second circulation water High-temperature water flowing into the hot water supply path 40 from the outward path 58 is mixed and supplied. The water in the hot water supply path 40 is not only supplied to the hot water tap 42 but also sent to the second circulation return path 60. In this state, when the high-temperature water from the tank 32 reaches the thermistor 50 and the detected temperature of the thermistor 50 reaches the hot water supply set temperature, the control unit 100 condenses the first three-way valve 52 of the hot water circulation unit 8. While the water sent from the water flow path 18b of the vessel 18 to the first circulation forward path 26 is switched to the state of being sent to the tank 32, the water from the tank 32 is condensed through the first circulation return path 28 through the second three-way valve 54. The state is switched to the state of being sent to the water flow path 18b of the vessel 18. As a result, as shown in FIG. 5, the hot-water tap 42 is supplied with water that has been mixed with high-temperature water from the tank 32 and low-temperature water from the bypass water passage 44 and adjusted to the hot-water supply set temperature. In addition, in parallel with the hot water supply to hot water tap 42, the tank heating operation is performed. When shifting from the hot water circulation operation to the hot water supply operation as described above, the control unit 100 can continuously operate the heat pump 10 and the circulation pump 12 without stopping. Thus, the boiling temperature in the tank boiling operation can be quickly stabilized.

  Control unit 100 closes hot water tap 42 when the sum of the flow rate detected by low-temperature flow meter 46 and the flow rate detected by high-temperature flow meter 48 falls below a predetermined value during the hot water supply operation. Is determined to have ended, and the hot water supply operation ends. When ending the hot water supply operation, the control unit 100 stops the compressor 16 and the fan 24 of the heat pump unit 4 and stops the circulation pump 12.

  When ending the hot water supply operation, the hot water circulation operation may be executed again in preparation for the subsequent hot water supply operation without stopping the heat pump 10 and the circulation pump 12. In this case, the control unit 100 sends the first three-way valve 52 of the hot water circulation unit 8 from the water flow path 18b of the condenser 18 to the first circulation forward path 26 without stopping the heat pump 10 and the circulation pump 12. The state is switched to a state in which water is sent to the second circulation forward path 58, and the second three-way valve 54 is set to a state where water from the second circulation return path 60 is sent to the water flow path 18b of the condenser 18 via the first circulation return path 28. Switch to As a result, the hot water circulation operation for the subsequent hot water supply operation is executed. By operating the heat pump 10 continuously without stopping, the boiling temperature in the hot water circulation operation can be quickly stabilized.

(Operation when starting hot water supply operation when hot water circulation operation is not executed)
When the hot water supply operation is started while the hot water circulation operation is not being performed, control unit 100 performs a different operation according to the elapsed time since the previous hot water supply operation was completed.

  If the time elapsed since the previous hot water supply operation was completed is less than a predetermined time (for example, 30 minutes), relatively high-temperature water remains in the hot water supply passage 40 between the tank 32 and the hot water tap 42. it is conceivable that. Therefore, in such a case, the control unit 100 controls the first three-way valve 52 of the hot water circulation unit 8 to transfer the water sent from the water flow path 18b of the condenser 18 to the first circulation forward path 26 to the tank 32. And the second three-way valve 54 is switched to a state in which the water from the tank 32 is sent to the water flow path 18b of the condenser 18 via the first circulation return path 28. Further, the control unit 100 drives the compressor 16 and the fan 24 of the heat pump unit 4 and also drives the circulation pump 12. As a result, as shown in FIG. 5, the hot-water tap 42 is supplied with water that has been mixed with high-temperature water from the tank 32 and low-temperature water from the bypass water passage 44 and adjusted to the hot-water supply set temperature. In addition, the tank heating operation is performed in parallel with the hot water supply from the tank 32 to the hot water tap 42.

  If the elapsed time since the previous hot water supply operation is completed exceeds a predetermined time (for example, 30 minutes), it is determined that relatively low-temperature water remains in the hot water supply passage 40 between the tank 32 and the hot water tap 42. Conceivable. Therefore, in such a case, the control unit 100 controls the first three-way valve 52 of the hot water circulation unit 8 to transfer the water sent from the water flow path 18b of the condenser 18 to the first circulation forward path 26 to the tank 32. And the second three-way valve 54 is switched to a state in which the water from the second circulation return path 60 is sent to the water flow path 18b of the condenser 18 via the first circulation return path 28. Further, the control unit 100 drives the compressor 16 and the fan 24 of the heat pump unit 4 and also drives the circulation pump 12. As a result, as shown in FIG. 6, the water in the hot water supply path 40 is sent not only to the hot water tap 42 but also to the second circulation return path 60, so that the hot water supply path 40 between the tank 32 and the hot water tap 42 is provided. Is quickly replaced with hot water from the tank 32. Further, the low-temperature water remaining in the hot water supply passage 40 between the tank 32 and the hot-water tap 42 is returned to the tank 32 after being heated by the heat pump 10, so that heat can be stored in the tank 32. In this state, when the high-temperature water from the tank 32 reaches the thermistor 50 and the detected temperature of the thermistor 50 reaches the hot water supply set temperature, the control unit 100 condenses the first three-way valve 52 of the hot water circulation unit 8. While the water sent from the water flow path 18b of the vessel 18 to the first circulation forward path 26 is maintained in a state of being sent to the tank 32, the water from the tank 32 is supplied to the second three-way valve 54 via the first circulation return path 28. The state is switched to a state of being sent to the water flow path 18b of the condenser 18. As a result, as shown in FIG. 5, the hot-water tap 42 is supplied with water that has been mixed with high-temperature water from the tank 32 and low-temperature water from the bypass water passage 44 and adjusted to the hot-water supply set temperature. In addition, in parallel with the hot water supply to hot water tap 42, the tank heating operation is performed.

  In the above embodiment, the configuration in which the circulation pump 12 is provided in the first circulation return path 28 on the downstream side (the heat pump 10 side) of the second three-way valve 54 has been described. It may be provided in the first circulation outward path 26 on the upstream side (on the side of the heat pump 10).

  In the above embodiment, the configuration in which both the first three-way valve 52 and the second three-way valve 54 are three-way switching valves has been described. However, one or both of the first three-way valve 52 and the second three-way valve 54 It may be replaced with an on-off valve, may be replaced with two flow control valves, or may be replaced with a three-way flow control valve.

  As described above, the hot water supply system 2 of the present embodiment includes the heat pump 10 for heating water, the tank 32 for storing water, the first circulation forward path 26 for sending water from the heat pump 10 to the tank 32, and the heat pump 10 A first circulation return path 28 for supplying water to the tank 32, a water supply path 38 for supplying water to the tank 32, a hot water supply path 40 for supplying hot water from the tank 32, and a bypass branched from the water supply path 38 to join the hot water supply path 40. A water passage 44, a second circulation outgoing passage 58 that branches off from the first circulation outgoing passage 26 and joins the hot water supply passage 40 downstream of the merging point of the bypass water passage 44, and a downstream side of the merging point of the second circulation outgoing passage 58 The second circulation return path 60 which branches off from the hot water supply path 40 and joins the first circulation return path 28, and the water circulating in the order of the heat pump 10, the first circulation forward path 26, the tank 32, and the first circulation return path 28. A circulating device capable of executing a circulation operation and a second circulation operation for circulating water in the order of the heat pump 10, the first circulation forward path 26, the second circulation forward path 58, the hot water supply path 40, the second circulation return path 60, and the first circulation return path 28. (Circulation pump 12, first three-way valve 52 and second three-way valve 54).

  In the above hot water supply system 2, the circulation device (the circulation pump 12, the first three-way valve 52 and the second three-way valve 54) is provided in the first circulation return path 28 downstream of the junction of the second circulation return path 60. Circulating pump 12 is provided.

  In the above hot water supply system 2, the first heating operation (tank boiling) in which the water is heated by the heat pump 10 while the first circulation operation is performed by the circulation devices (the circulation pump 12, the first three-way valve 52, and the second three-way valve 54). Operation) and a second heating operation (immediate hot water circulation operation) of heating water with the heat pump 10 while performing the second circulation operation with the circulation device.

  In the above hot water supply system 2, the target boiling temperature of the heat pump 10 in the second heating operation (quick water circulation operation) is higher than the target boiling temperature of the heat pump 10 in the first heating operation (tank heating operation). Is also low.

  In the above hot water supply system 2, the first heating operation (tank heating operation) and the second heating operation (quick hot water circulation operation) can be continuously performed without stopping the heat pump 10.

  As described above, the specific examples of the present invention have been described in detail. However, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and alterations of the specific examples illustrated above. In addition, the technical elements described in the present specification or the drawings exert technical utility singly or in various combinations, and are not limited to the combinations described in the claims at the time of filing. The technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

2: Hot water supply system 4: Heat pump unit 6: Tank unit 8: Hot water circulation unit 10: Heat pump 12: Circulation pump 14: Refrigerant circulation path 16: Compressor 18: Condenser 18a: Refrigerant flow path 18b: Water flow path 20: Expansion Valve 22: Evaporator 24: Fan 26: First circulation forward path 28: First circulation return path 30: Thermistor 32: Tank 32a: Thermistor 32b: Thermistor 32c: Thermistor 32d: Thermistor 34: Low-temperature side flow control valve 36: High-temperature side flow Adjusting valve 38: Water supply path 40: Hot water supply path 42: Hot water supply tap 44: Bypass water path 46: Low temperature side flow meter 48: High temperature side flow meter 50: Thermistor 52: First three-way valve 54: Second three-way valve 56: Check valve 58: second circulation outward path 60: second circulation return path 100: control unit

Claims (4)

A heat pump for heating water,
A tank for storing water,
A first circulation path for sending water from the heat pump to the tank;
A first circulation return path for sending water from the tank to the heat pump;
A water supply channel that supplies water to the tank;
A hot water supply channel that supplies water from the tank,
A bypass channel that branches off from the water supply channel and joins the hot water channel;
A second circulation forward branching off from the first circulation outward and joining a hot water supply passage downstream of a junction of the bypass water passage;
A second circulation return path that branches off from the hot water supply path downstream of the junction of the second circulation outward path and joins the first circulation return path;
Temperature detection means for detecting the temperature of water flowing through the hot water supply path upstream of the junction of the second circulation forward path;
A first circulation operation in which water is circulated in the order of a heat pump, a first circulation forward path, a tank, and a first circulation return path, and a heat pump, a first circulation forward path, a second circulation forward path, a hot water supply path, a second circulation return path, and a first circulation return path. A circulation device capable of executing a second circulation operation for sequentially circulating water ,
A first heating operation for heating water with a heat pump while performing the first circulation operation with the circulation device, and a second heating operation for heating water with the heat pump while performing the second circulation operation with the circulation device,
During the execution of the second heating operation, when hot water supply to the hot water supply path is started, and when the temperature detected by the temperature detection means is lower than the predetermined temperature, the second heating operation is continued as it is, and the temperature detection means A hot water supply system that switches from the second heating operation to the first heating operation when the temperature detected in step (1) is equal to or higher than a predetermined temperature .   The circulation device further includes a circulation pump provided in the first circulation return path upstream of the branch point of the second circulation forward path or the first circulation return path downstream of the junction of the second circulation return path. Item 1. Hot water supply system. The hot water supply system according to claim 1, wherein a target boiling temperature of the heat pump during the second heating operation is lower than a target boiling temperature of the heat pump during the first heating operation. The hot water supply system according to any one of claims 1 to 3, wherein the first heating operation and the second heating operation can be continuously performed without stopping the heat pump.

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