JP7508933B2 - Hot water system - Google Patents

Description

The present invention relates to a hot water supply system.

As is well known, the energy efficiency of a heat pump water heater is indicated by the coefficient of performance (COP). In order to increase this COP, various improvements have been made to the refrigeration cycle. For example, Patent Documents 1 and 2 describe a hot water supply system in which a supercooler is provided after the condenser of the heat pump circuit, and water stored in a hot water tank is circulated through the condenser to heat it, while make-up water for the hot water tank is circulated through the supercooler to preheat it.

Japanese Patent Publication No. 2-27582 Japanese Utility Model Application Publication No. 3-3665

In a configuration in which the water stored in the hot water tank is circulated and heated using only a condenser, the temperature difference between the stored water and the heat source air increases as the temperature of the stored water rises, making it difficult to maintain a high COP. In contrast, the hot water supply systems described in Patent Documents 1 and 2 use a supercooler to preheat low-temperature make-up water, thereby strengthening the heating capacity of the entire system and increasing the COP.
However, in such a hot water supply system, when the temperature of the make-up water source is low, the liquid refrigerant flowing into the expansion valve may be cooled excessively by passing through the condenser and the subcooler in sequence. When highly subcooled liquid refrigerant is supplied to the evaporator, wet steam is sent to the compressor without sufficient vaporization in the evaporator. When the compressor draws in wet steam, the compressor may be damaged by liquid hammer caused by liquid compression.

The present invention was made in consideration of the above problems, and aims to provide a hot water supply system that can prevent damage to the compressor in a configuration in which a heat pump circuit is provided with a heat exchanger for heating stored water and a heat exchanger for heating make-up water.

The present invention relates to a hot water supply system comprising: a vapor compression heat pump circuit in which a compressor, a first heat dissipation heat exchanger, a second heat dissipation heat exchanger, an expansion valve, and a heat absorption heat exchanger are connected in a ring shape by a refrigerant circulation line, and hot water is extracted in the first heat dissipation heat exchanger and/or the second heat dissipation heat exchanger by driving the compressor; a hot water storage tank for storing make-up water; a water circulation line for circulating water stored in the hot water storage tank to the first heat dissipation heat exchanger; a make-up water line for supplying make-up water to the hot water storage tank while circulating make-up water to the second heat dissipation heat exchanger; a refrigerant temperature adjustment means for adjusting the temperature of liquid refrigerant flowing into the expansion valve; and a control means for controlling the refrigerant temperature adjustment means, wherein the refrigerant temperature adjustment means includes a bypass line for bypassing the refrigerant or the circulating water from the first heat dissipation heat exchanger, or for bypassing the refrigerant or the make-up water from the second heat dissipation heat exchanger, and a distribution valve for adjusting the distribution amount of the refrigerant, the circulating water, or the make-up water supplied to the bypass line .

The refrigerant temperature adjustment means of the hot water supply system preferably includes a temperature sensor that detects the temperature of the liquid refrigerant flowing into the expansion valve, a first bypass line that is connected to the refrigerant circulation line and bypasses the refrigerant from the second heat dissipation heat exchanger, and a first distribution valve that adjusts the distribution amount of the refrigerant supplied to the second heat dissipation heat exchanger and the refrigerant supplied to the first bypass line, and the control means preferably controls the first distribution valve so that the temperature detected by the temperature sensor becomes a target temperature while the compressor is operating.

The refrigerant temperature adjustment means of the hot water supply system preferably includes a temperature sensor that detects the temperature of the liquid refrigerant flowing into the expansion valve, a pressure sensor that detects the pressure of the liquid refrigerant flowing into the expansion valve, a first bypass line that is connected to the refrigerant circulation line and bypasses the refrigerant from the second heat dissipation heat exchanger, and a first distribution valve that adjusts the distribution amount of the refrigerant sent to the second heat dissipation heat exchanger and the refrigerant sent to the first bypass line, and the control means preferably determines the condensation temperature of the gas refrigerant from the pressure detected by the pressure sensor while the compressor is running, calculates the degree of subcooling of the liquid refrigerant by subtracting the temperature detected by the temperature sensor from the condensation temperature, and controls the first distribution valve so that the calculated degree of subcooling becomes the target degree of subcooling.

The refrigerant temperature adjustment means of the hot water supply system preferably includes a temperature sensor that detects the temperature of the liquid refrigerant flowing into the expansion valve, a second bypass line that is connected to the make-up water line and bypasses the make-up water from the second heat dissipation heat exchanger, and a second distribution valve that adjusts the distribution amount of the make-up water supplied to the second heat dissipation heat exchanger and the make-up water supplied to the second bypass line, and the control means preferably controls the second distribution valve so that the temperature detected by the temperature sensor becomes a target temperature while the compressor is operating.

The refrigerant temperature adjustment means of the hot water supply system preferably includes a temperature sensor that detects the temperature of the liquid refrigerant flowing into the expansion valve, a pressure sensor that detects the pressure of the liquid refrigerant flowing into the expansion valve, a second bypass line that is connected to the make-up water line and bypasses the make-up water from the second heat dissipation heat exchanger, and a second distribution valve that adjusts the distribution amount of the make-up water supplied to the second heat dissipation heat exchanger and the make-up water supplied to the second bypass line, and the control means preferably determines the condensation temperature of the gas refrigerant from the pressure detected by the pressure sensor while the compressor is in operation, calculates the degree of subcooling of the liquid refrigerant by subtracting the temperature detected by the temperature sensor from the condensation temperature, and controls the second distribution valve so that the calculated degree of subcooling becomes the target degree of subcooling.

The refrigerant temperature adjustment means of the hot water supply system preferably includes a temperature sensor that detects the temperature of the liquid refrigerant flowing into the expansion valve, a third bypass line that is connected to the refrigerant circulation line and bypasses the refrigerant from the first heat dissipation heat exchanger, and a third distribution valve that adjusts the distribution amount of the refrigerant supplied to the first heat dissipation heat exchanger and the refrigerant supplied to the third bypass line, and the control means preferably controls the third distribution valve so that the temperature detected by the temperature sensor becomes a target temperature while the compressor is operating.

The refrigerant temperature adjustment means of the hot water supply system preferably includes a temperature sensor that detects the temperature of the liquid refrigerant flowing into the expansion valve, a pressure sensor that detects the pressure of the liquid refrigerant flowing into the expansion valve, a third bypass line that is connected to the refrigerant circulation line and bypasses the refrigerant from the first heat dissipation heat exchanger, and a third distribution valve that adjusts the distribution amount of the refrigerant supplied to the first heat dissipation heat exchanger and the refrigerant supplied to the third bypass line, and the control means preferably determines the condensation temperature of the gas refrigerant from the pressure detected by the pressure sensor while the compressor is in operation, calculates the degree of subcooling of the liquid refrigerant by subtracting the temperature detected by the temperature sensor from the condensation temperature, and controls the third distribution valve so that the calculated degree of subcooling becomes the target degree of subcooling.

The refrigerant temperature adjustment means of the hot water supply system preferably includes a temperature sensor that detects the temperature of the liquid refrigerant flowing into the expansion valve, a fourth bypass line that is connected to the water circulation line and bypasses the circulating water from the first heat dissipation heat exchanger, and a fourth distribution valve that adjusts the distribution amount of the circulating water supplied to the first heat dissipation heat exchanger and the circulating water supplied to the fourth bypass line, and the control means preferably controls the fourth distribution valve so that the temperature detected by the temperature sensor becomes a target temperature while the compressor is operating.

The refrigerant temperature adjustment means of the hot water supply system preferably includes a temperature sensor that detects the temperature of the liquid refrigerant flowing into the expansion valve, a pressure sensor that detects the pressure of the liquid refrigerant flowing into the expansion valve, a fourth bypass line that is connected to the water circulation line and bypasses the circulating water from the first heat dissipation heat exchanger, and a fourth distribution valve that adjusts the distribution amount of the circulating water supplied to the first heat dissipation heat exchanger and the circulating water supplied to the fourth bypass line, and the control means preferably determines the condensation temperature of the gas refrigerant from the pressure detected by the pressure sensor while the compressor is operating, calculates the degree of subcooling of the liquid refrigerant by subtracting the temperature detected by the temperature sensor from the condensing temperature, and controls the fourth distribution valve so that the calculated degree of subcooling becomes the target degree of subcooling.

According to the present invention, it is possible to provide a hot water supply system that can prevent damage to the compressor in a configuration in which a heat pump circuit is provided with a heat exchanger for heating stored water and a heat exchanger for heating make-up water.

1 is a diagram illustrating a schematic configuration of a hot water supply system according to a first embodiment of the present invention. FIG. 10 is a diagram illustrating a schematic configuration of a hot water supply system according to a modified example of the above embodiment. FIG. 5 is a diagram illustrating a schematic configuration of a hot water supply system according to a second embodiment of the present invention. FIG. 10 is a diagram illustrating a schematic configuration of a hot water supply system according to a modified example of the above embodiment. FIG. 10 is a diagram illustrating a schematic configuration of a hot water supply system according to a third embodiment of the present invention. FIG. 10 is a diagram illustrating a schematic configuration of a hot water supply system according to a modified example of the above embodiment. FIG. 10 is a diagram illustrating a schematic configuration of a hot water supply system according to a fourth embodiment of the present invention. FIG. 10 is a diagram illustrating a schematic configuration of a hot water supply system according to a modified example of the above embodiment.

First Embodiment
Hereinafter, a first embodiment of a hot water supply system 1 of the present invention will be described with reference to the drawings. Note that the term "line" in this specification is a general term for a line, such as a flow path, a pathway, or a pipe, through which a fluid can flow.

Fig. 1 is a diagram showing a schematic configuration of a hot water supply system 1 according to the present embodiment. As shown in Fig. 1, the hot water supply system 1 according to the present embodiment includes a heat pump circuit 10, a hot water storage tank 60, a water circulation line L1 for circulating stored water W3 in the hot water storage tank 60 as circulating water W1, a make-up water line L2 for supplying make-up water W2 to the hot water storage tank 60, and a control unit 100.
This hot water supply system 1 is a system that supplies water W3 stored in a hot water storage tank 60 that has been heated by a heat pump circuit 10 as hot water W4 to a location where hot water or heat is demanded.

The heat pump circuit 10 is a vapor compression type heat pump circuit in which a compressor 11, a first heat dissipation heat exchanger 12A (condenser 12A), a second heat dissipation heat exchanger 12B (subcooler 12B), an expansion valve 13, and a heat absorption heat exchanger 14 (evaporator 14) are connected in a ring shape by a refrigerant circulation line L9, and heat is absorbed by the heat absorption heat exchanger 14 when the compressor 11 is driven, while hot heat is extracted by the first heat dissipation heat exchanger 12A and/or the second heat dissipation heat exchanger 12B. Refrigerant R flows through this refrigerant circulation line L9.

The compressor 11 has an electric motor 15 as a driving source, and compresses gaseous refrigerant R (gas refrigerant R) such as fluorocarbon gas to produce high-temperature, high-pressure refrigerant R. The first heat dissipation heat exchanger 12A is a condenser that dissipates heat into circulating water W1 sent through the water circulation line L1 to condense and liquefy the refrigerant R from the compressor 11. The second heat dissipation heat exchanger 12B is a supercooler that dissipates heat into make-up water W2 sent through the make-up water line L2 to supercool the refrigerant R (liquid refrigerant R) that has passed through the first heat dissipation heat exchanger 12A. The expansion valve 13 passes the refrigerant R sent from the second heat dissipation heat exchanger 12B, thereby reducing the pressure and temperature of the refrigerant R. The heat absorption heat exchanger 14 is an evaporator that absorbs heat from a heat source fluid and evaporates the refrigerant R sent from the expansion valve 13. Various fluids such as heat source air and heat source water can be used as the heat source fluid.

The first heat dissipation heat exchanger 12A for heating the stored water performs indirect heat exchange between the circulating water W1 and the refrigerant R, and dissipates latent heat and sensible heat of the refrigerant R. The first heat dissipation heat exchanger 12A condenses and liquefies the refrigerant R using the circulating water W1, and also warms the circulating water W1 using the refrigerant R.
The second heat dissipation heat exchanger 12B for heating make-up water indirectly exchanges heat between the make-up water W2 and the refrigerant R, and dissipates sensible heat of the refrigerant R. The second heat dissipation heat exchanger 12B supercools the refrigerant R using the make-up water W2, and also heats the make-up water W2 using the refrigerant R.
In this way, by using separate heat exchangers for condensing and supercooling the refrigerant R, the design of the heat exchangers is simplified, and costs can be reduced. In addition, a general-purpose heat exchanger can be used.
In addition, if the condensation and liquefaction of the gas refrigerant R in the first heat dissipation heat exchanger 12A is limited to a partial phase change due to operating conditions, etc., the remaining gas refrigerant R is condensed and liquefied in the second heat dissipation heat exchanger 12B.

The expansion valve 13 is configured as a proportional control needle valve, and the flow rate of the refrigerant R flowing through the refrigerant circulation line L9 can be adjusted by changing the stroke of the needle valve and adjusting the valve opening by controlling the rotation speed of the driving stepping motor.

As described above, in the heat pump circuit 10, the refrigerant R absorbs heat from the outside and vaporizes in the heat absorption heat exchanger 14, while in the first heat dissipation heat exchanger 12A and the second heat dissipation heat exchanger 12B, the refrigerant R dissipates heat to the outside, condenses into liquid, and is supercooled. Using this principle, the heat pump circuit 10 pumps heat from the heat source fluid in the heat absorption heat exchanger 14, heats the circulating water W1 in the first heat dissipation heat exchanger 12A, and heats the make-up water W2 in the second heat dissipation heat exchanger 12B.

The heat pump circuit 10 of this embodiment further includes a refrigerant temperature sensor 16 as a temperature sensor that detects the temperature of the liquid refrigerant R flowing into the expansion valve 13, a first bypass line L11 connected to the refrigerant circulation line L9 and bypassing the liquid refrigerant R from the second heat dissipation heat exchanger 12B, and a first distribution valve 31 that adjusts the distribution amount of the liquid refrigerant R supplied to the second heat dissipation heat exchanger 12B and the liquid refrigerant R supplied to the first bypass line L11.

The first bypass line L11 branches off from the refrigerant circulation line L9 upstream of the second heat dissipation heat exchanger 12B (between the first heat dissipation heat exchanger 12A and the second heat dissipation heat exchanger 12B) and merges with the refrigerant circulation line L9 downstream of the second heat dissipation heat exchanger 12B (between the second heat dissipation heat exchanger 12B and the expansion valve 13).

The refrigerant temperature sensor 16 is disposed downstream of the junction of the refrigerant circulation line L9 and the first bypass line L11 and upstream of the expansion valve 13. More preferably, the refrigerant temperature sensor 16 is disposed upstream of the expansion valve 13 and in the vicinity of the expansion valve 13 in order to measure the temperature of the refrigerant R immediately before it flows into the expansion valve 13.

The first distribution valve 31 is provided in the first bypass line L11. The first distribution valve 31 is configured to have an adjustable valve opening. By adjusting the valve opening of the first distribution valve 31, it is possible to adjust the distribution amount of the liquid refrigerant R to be supplied to the second heat dissipation heat exchanger 12B and the liquid refrigerant R to be supplied to the first bypass line L11.
Here, when the first distributor valve 31 is open, the first branch flow of the refrigerant R flowing through the refrigerant circulation line L9 and flowing through the first bypass line L11 only undergoes a relatively small friction loss in the valve chamber while passing through the first distributor valve 31. On the other hand, the second branch flow of the refrigerant R flowing through the refrigerant circulation line L9 in which the second heat dissipation heat exchanger 12B is disposed undergoes a relatively large friction loss in the second heat dissipation heat exchanger 12B while passing through the second heat dissipation heat exchanger 12B. Therefore, the flow rate ratio of the refrigerant R is "first branch flow>second branch flow", and most of the refrigerant R flows through the first bypass line L11. Therefore, even with such a simple configuration, the distribution amount of the liquid refrigerant R to be fed to the second heat dissipation heat exchanger 12B and the liquid refrigerant R to be fed to the first bypass line L11 can be adjusted by adjusting the valve opening degree of the first distributor valve 31.

The refrigerant temperature sensor 16, the first bypass line L11, and the first distribution valve 31 constitute the refrigerant temperature adjustment means 50 in this embodiment. The refrigerant temperature adjustment means 50 is controlled by the control unit 100 described below, and adjusts the temperature of the liquid refrigerant R flowing into the expansion valve 13.

The hot water tank 60 is a tank that stores the circulating water W1 and makeup water W2 heated by the heat pump circuit 10 as stored water W3. The stored water W3 in the hot water tank 60 is supplied as hot water W4 to hot water demand points or hot heat demand points through the hot water supply line L4.

The hot water tank 60 is equipped with a hot water temperature sensor 61 that detects the temperature of the stored water W3 in the hot water tank 60. The hot water temperature sensor 61 monitors the temperature of the stored water W3 that is to be supplied to a hot water demand point or a hot heat demand point as hot water supply water W4.

The hot water tank 60 is equipped with a water level sensor 62 that detects the water level in the hot water tank 60. In this embodiment, the water level sensor 62 is configured as an electrode-type water level detector equipped with multiple electrode rods. Specifically, multiple electrode rods of different lengths are inserted and held with their bottom ends at different height positions. Each electrode rod detects the presence or absence of a water level at its bottom end depending on whether or not its bottom end is immersed in water. In this way, the water level sensor 62 detects the water level of the stored water W3 in the hot water tank 60.

The water circulation line L1 is connected to the hot water storage tank 60 on its upstream side and also connected to the hot water storage tank 60 on its downstream side. The water circulation line L1 forms a circulation path that circulates the stored water W3 in the hot water storage tank 60 as circulating water W1. The stored water W3 in the hot water storage tank 60 passes through the first heat dissipation heat exchanger 12A via the water circulation line L1, where it is heated, and returns to the hot water storage tank 60. In the water circulation line L1, from the upstream side, a water circulation pump 21, a first heat dissipation heat exchanger 12A, and a first temperature sensor 22 are arranged in that order.

The rotation speed of the water circulation pump 21 can be controlled by an inverter. By changing the rotation speed of the water circulation pump 21, the flow rate of the circulating water W1 circulating through the water circulation line L1 can be adjusted.

The first temperature sensor 22 is disposed downstream of the first heat dissipation heat exchanger 12A and detects the temperature of the circulating water W1 flowing out from the first heat dissipation heat exchanger 12A.

The makeup water line L2 is connected on its upstream side to a makeup water source such as a makeup water tank (not shown) and on its downstream side to the hot water storage tank 60. The makeup water line L2 is a line that supplies makeup water W2 to the hot water storage tank 60 while circulating the makeup water W2 through the second heat dissipation heat exchanger 12B. On the makeup water line L2, a makeup water valve 25, a second heat dissipation heat exchanger 12B, and a second temperature sensor 26 are arranged in this order from the upstream side.

The makeup water valve 25 is configured so that the valve opening degree can be adjusted. By adjusting the valve opening degree of the makeup water valve 25, the flow rate of makeup water W2 flowing through the makeup water line L2 can be adjusted.

The second temperature sensor 26 is disposed downstream of the second heat dissipation heat exchanger 12B and detects the temperature of the makeup water W2 flowing out from the second heat dissipation heat exchanger 12B.

The makeup water line L2 includes a second bypass line L12 serving as a makeup water bypass line. The second bypass line L12 is a bypass line that causes makeup water W2 to bypass the second heat dissipation heat exchanger 12B. A second distribution valve 32 serving as a makeup water distribution valve is disposed in the second bypass line L12.

The second distribution valve 32 adjusts the distribution amount of makeup water W2 supplied to the second heat dissipation heat exchanger 12B and makeup water W2 supplied to the second bypass line L12. The valve opening degree of the second distribution valve 32 may be adjusted automatically or manually. For example, when a sudden drop in the water level of the stored water W3 in the hot water storage tank 60 is detected, the second distribution valve 32 may be opened automatically or manually. This prevents makeup water W2 that has not been heated by the second heat dissipation heat exchanger 12B from being rapidly replenished into the hot water storage tank 60, causing the hot water storage tank 60 to become dry.

The stored water W3 in the hot water storage tank 60, which has been heated by passing through the water circulation line L1 and the make-up water line L2, is supplied as hot water W4 to the hot water demand point or the heat demand point through the hot water supply line L4.

The hot water demand point refers to various production facilities in a factory that consume the stored water W3 by using the hot water W4 as a fluid. Examples of hot water demand points include container washing equipment (rinsers) for food, beverages, and medicines, and heat sterilization equipment (pasteurizers) for bottled, canned, and bagged products.
On the other hand, the heat demand point refers to a production facility or the like that uses only the thermal energy of the hot water W4 and does not consume the stored water W3. The thermal energy is utilized through various heat exchangers, and the hot water W4 whose temperature has been reduced by the extraction of thermal energy is returned to the hot water storage tank 60 through a hot water return line (not shown). Examples of the heat demand point include a degreasing tank or chemical conversion tank in a painting facility for metal processed products, and an air handling unit in an air conditioning facility.

Next, the control unit 100 (control means 100) of the hot water supply system 1 of this embodiment will be described. The control unit 100 is configured with a microprocessor including a CPU and a memory. The control unit 100 includes, as functional blocks, a water circulation pump control unit 110 as a circulating water flow rate control unit, a make-up water valve control unit 120 as a make-up water flow rate control unit, and a distribution valve control unit 130 as a refrigerant temperature control unit.
1 indicate the paths of major electrical connections in this embodiment. In reality, these electrical connections go through the control unit 100, but this is omitted in the illustration.

The water circulation pump control unit 110 acquires the temperature detected by the first temperature sensor 22, and controls the drive frequency of the water circulation pump 21 constituting the circulating water flow rate adjustment means according to the detected temperature. Specifically, the water circulation pump control unit 110 controls the drive frequency of the water circulation pump 21 so that the temperature detected by the first temperature sensor 22 becomes the target hot water outlet temperature, and adjusts the flow rate of the circulating water W1. As a more specific control, for example, it is preferable to adopt feedback control in which the hot water outlet temperature detected in real time by the first temperature sensor 22 is used as a feedback value, and the drive frequency of the water circulation pump is adjusted so that the hot water outlet temperature converges to the target hot water outlet temperature. In addition to proportional control (P control), the feedback control can adopt a calculation algorithm of the manipulated variable that combines this with integral control (I control) and/or differential control (D control).

As a result, the circulating water W1 sent from the hot water storage tank 60 to the first heat dissipation heat exchanger 12A is heated to the target hot water outlet temperature (e.g., 60°C) in the first heat dissipation heat exchanger 12A, and then returned to the hot water storage tank 60 at a constant temperature. Therefore, even if there are seasonal variations in the temperature of the heat source fluid (e.g., heat source air) supplied to the heat absorption heat exchanger 14, or even if there are variations in the temperature of the makeup water W2 after heating in the second heat dissipation heat exchanger 12B, hot water at the required temperature (e.g., the hot water supply temperature required at the hot water demand point or the hot heat demand point) can be quickly stored in the hot water storage tank 60.

The make-up water valve control unit 120 acquires water level information of the stored water W3 in the hot water storage tank 60 detected by the water level sensor 62, and controls the valve opening of the make-up water valve 25 constituting the make-up water flow rate adjustment means according to the water level information. Specifically, the make-up water valve control unit 120 controls the make-up water valve 25 to decrease its opening as the water level detected by the water level sensor 62 increases, thereby decreasing the make-up water flow rate, and the make-up water valve 25 to increase its opening as the water level detected by the water level sensor 62 decreases, thereby increasing the make-up water flow rate. For example, when the water level is full, the valve opening of the make-up water valve 25 is set to 0% (fully closed), when the water level is just before drought, the valve opening of the make-up water valve 25 is set to 100% (fully open), and when the water level is between these levels, the valve opening of the make-up water valve 25 is set to 5% to 95%.

In this way, the valve opening of the make-up water valve 25 is reduced as the water level detected by the water level sensor 62 increases, while the valve opening of the make-up water valve 25 is increased as the water level detected by the water level sensor 62 decreases. This increases or decreases the make-up water flow rate in response to an increase or decrease in hot water demand. In other words, the make-up water valve 25 is not closed unless the hot water demand becomes zero, and make-up water W2 continues to flow to the second heat dissipation heat exchanger 12B. This allows the liquid refrigerant R to continue to be supercooled even when the hot water demand is low, thereby increasing the COP.

In addition, the make-up water valve control unit 120 may control the valve opening degree of the make-up water valve 25 based on the temperature detected by the second temperature sensor 26 that detects the temperature of the make-up water W2 flowing out from the second heat dissipation heat exchanger 12B in addition to the water level detected by the water level sensor 62. In this case, the make-up water valve control unit 120 adjusts the valve opening degree of the make-up water valve 25 constituting the make-up water flow rate adjustment means according to the water level information detected by the water level sensor 62, and controls the valve opening degree of the make-up water valve 25 so that the temperature detected by the second temperature sensor 26 does not exceed the target hot water outlet temperature (e.g., 60°C) when the temperature detected by the second temperature sensor 26 exceeds the target hot water outlet temperature (e.g., 60°C) of the first heat dissipation heat exchanger 12A. This allows the hot water storage tank 60 to be rapidly replenished with hot water that does not exceed the required temperature (e.g., the hot water supply temperature required at the hot water demand point or the hot heat demand point) while continuing to supercool the liquid refrigerant R.

The distribution valve control unit 130 acquires the temperature detected by the refrigerant temperature sensor 16, and performs control to adjust the valve opening of the first distribution valve 31 constituting the refrigerant temperature adjustment means 50 according to the detected temperature. Specifically, the distribution valve control unit 130 controls the first distribution valve 31 so that the temperature detected by the refrigerant temperature sensor 16 becomes the target temperature while the compressor 11 is in operation. As a more specific control, for example, it is preferable to adopt feedback control in which the refrigerant temperature detected in real time by the refrigerant temperature sensor 16 is used as a feedback value and the valve opening of the first distribution valve 31 is adjusted so that the refrigerant temperature converges to the target temperature. As the feedback control, in addition to proportional control (P control), a calculation algorithm of the manipulated variable that combines this with integral control (I control) and/or differential control (D control) can be adopted.
Here, the target temperature is set manually or automatically depending on the device state and the like.
This adjusts the amount of liquid refrigerant R bypassed to the second heat dissipation heat exchanger 12B, and suppresses the amount of cooling of the liquid refrigerant R in the second heat dissipation heat exchanger 12B.

With the above configuration, even if the water source temperature of the make-up water is low, the temperature of the liquid refrigerant R flowing into the expansion valve can be kept constant so as not to become highly supercooled. This prevents highly supercooled liquid refrigerant R from being supplied to the heat absorption heat exchanger 14, and prevents the compressor 11 from drawing in refrigerant R in a wet vapor state. This allows the refrigeration cycle to operate optimally while preventing damage to the compressor 11.

Next, a modified example of the first embodiment will be described with reference to the drawings. FIG. 2 is a diagram showing a schematic configuration of a hot water supply system according to a modified example of the first embodiment. This modified example further includes a refrigerant pressure sensor 17 that detects the pressure of the liquid refrigerant R flowing into the expansion valve 13, and the distribution valve control unit 130 controls the first distribution valve 31 based on the temperature detected by the refrigerant temperature sensor 16 and the pressure detected by the refrigerant pressure sensor 17.

As shown in FIG. 2, the heat pump circuit 10 of this modified example includes a refrigerant pressure sensor 17 that detects the pressure of the liquid refrigerant R flowing into the expansion valve 13. The control unit 100 of this modified example also includes a subcooling degree calculation unit 140 that calculates the subcooling degree of the liquid refrigerant R flowing into the expansion valve 13.

The refrigerant pressure sensor 17, like the refrigerant temperature sensor 16, is disposed downstream of the junction of the refrigerant circulation line L9 and the first bypass line L11 and upstream of the expansion valve 13. More preferably, the refrigerant pressure sensor 17 is disposed upstream of the expansion valve 13 and in the vicinity of the expansion valve 13 in order to measure the pressure of the refrigerant R immediately before it flows into the expansion valve 13.

In this modified example, the refrigerant pressure sensor 17, the refrigerant temperature sensor 16, the first bypass line L11, and the first distribution valve 31 constitute the refrigerant temperature adjustment means 50.

The subcooling degree calculation unit 140 calculates the degree of subcooling of the liquid refrigerant R flowing into the expansion valve 13. Specifically, the subcooling degree calculation unit 140 obtains the condensation temperature of the gas refrigerant R from the pressure detected by the refrigerant pressure sensor 17, and calculates the degree of subcooling of the liquid refrigerant R by subtracting the temperature detected by the refrigerant temperature sensor 16 from this condensation temperature.

The distribution valve control unit 130 controls the first distribution valve 31 constituting the refrigerant temperature adjustment means 50 so that the calculated degree of subcooling (the value calculated by the subcooling degree calculation unit 140) becomes the target degree of subcooling, thereby adjusting the degree of subcooling of the liquid refrigerant R flowing into the expansion valve 13. As a specific control, for example, it is preferable to adopt feedback control in which the calculated degree of subcooling calculated in real time by the subcooling degree calculation unit 140 is used as a feedback value, and the valve opening degree of the first distribution valve 31 is adjusted so that this calculated degree of subcooling converges to the target degree of subcooling. As the feedback control, in addition to proportional control (P control), a calculation algorithm of the manipulated variable that combines this with integral control (I control) and/or differential control (D control) can be adopted.
This adjusts the amount of liquid refrigerant R bypassed to the second heat dissipation heat exchanger 12B, and adjusts the degree of subcooling of the liquid refrigerant R flowing into the expansion valve 13.
Here, the target degree of supercooling is set manually or automatically depending on the state of the device, etc.

In this way, the subcooling degree calculation unit 140 accurately calculates the degree of subcooling of the liquid refrigerant R flowing into the expansion valve 13, and the distribution valve control unit 130 controls the first distribution valve 31 so that the calculated degree of subcooling becomes the target degree of subcooling, thereby adjusting the amount of liquid refrigerant R bypassed to the second heat dissipation heat exchanger 12B and suppressing the amount of cooling of the liquid refrigerant R in the second heat dissipation heat exchanger 12B. As a result, even if the water source temperature of the makeup water W2 is low, the temperature of the liquid refrigerant R flowing into the expansion valve 13 can be kept at a constant temperature that does not become highly subcooled.

In this embodiment, the first distribution valve 31 is provided in the first bypass line L11, but is not limited thereto. The first distribution valve 31 may be any valve that has a function of adjusting the distribution amount of the liquid refrigerant R supplied to the second heat dissipation heat exchanger 12B and the liquid refrigerant R supplied to the first bypass line L11, and may be, for example, a three-way valve provided at a branching point where the first bypass line L11 branches off from the refrigerant circulation line L9.
In the case of a three-way valve, a valve opening designation signal of 0 to 100% is input to an actuator circuit that adjusts the valve opening, thereby adjusting the valve opening of the first outlet port side toward the second heat dissipation heat exchanger 12B and the valve opening of the second outlet port side toward the first bypass line L11. This adjusts the flow rate ratio between the flow rate of the liquid refrigerant R flowing into the second heat dissipation heat exchanger 12B and the flow rate of the liquid refrigerant R flowing into the first bypass line L11. However, the sum of the flow rate ratios of the first outlet port side and the second outlet port side is always 100%. Note that the valve opening of the three-way valve is based on the valve opening of the first outlet port side, and when the valve opening of the first outlet port side is 0% → 25% → 50% → 75% → 100%, the valve opening of the second outlet port side is 100% → 75% → 50% → 25% → 0%. Even when using such a three-way valve, it is preferable to employ feedback control in which, for example, the refrigerant temperature detected in real time by the refrigerant temperature sensor 16 and the calculated degree of subcooling calculated in real time by the subcooling degree calculation unit 140 are used as feedback values, and the valve opening degree of the three-way valve is adjusted so that these refrigerant temperatures and the calculated degree of subcooling converge to target values.

The hot water supply system 1 of the first embodiment described above provides the following advantages (1) to (3).

(1) The hot water supply system 1 of this embodiment includes a vapor compression type heat pump circuit 10 in which a compressor 11, a first heat dissipation heat exchanger 12A, a second heat dissipation heat exchanger 12B, an expansion valve 13 and a heat absorption heat exchanger 14 are connected in a ring shape by a refrigerant circulation line L9, and which extracts hot heat in the first heat dissipation heat exchanger 12A and/or the second heat dissipation heat exchanger 12B by driving the compressor 11, a hot water storage tank 60 for storing make-up water W2, a water circulation line L1 for circulating the stored water W3 in the hot water storage tank 60 to the first heat dissipation heat exchanger 12A, a make-up water line L2 for supplying the make-up water W2 to the hot water storage tank 60 while circulating it to the second heat dissipation heat exchanger 12B, a refrigerant temperature adjustment means 50 for adjusting the temperature of the liquid refrigerant R flowing into the expansion valve 13, and a control means 100 for controlling the refrigerant temperature adjustment means 50.
In this way, since the refrigerant temperature adjustment means 50 that adjusts the temperature of the liquid refrigerant R flowing into the expansion valve 13 and the control means 100 that controls the refrigerant temperature adjustment means 50 are provided, it is possible to prevent the refrigerant R in a highly supercooled state from being supplied to the heat absorption heat exchanger 14 (evaporator 14), and thus prevent the compressor 11 from drawing in wet steam. This makes it possible to optimally operate the refrigeration cycle while preventing damage to the compressor 11.

(2) The refrigerant temperature adjustment means 50 of the hot water supply system 1 of this embodiment includes a temperature sensor 16 that detects the temperature of the liquid refrigerant R flowing into the expansion valve 13, a first bypass line L11 connected to the refrigerant circulation line L9 and bypassing the refrigerant R from the second heat dissipation heat exchanger 12B, and a first distribution valve 31 that adjusts the distribution amount of the refrigerant R supplied to the second heat dissipation heat exchanger 12B and the refrigerant R supplied to the first bypass line L11, and the control means 100 controls the first distribution valve 31 so that the detected temperature of the temperature sensor 16 becomes the target temperature while the compressor 11 is operating.
In this way, by controlling the first distribution valve 31 so that the detected temperature of the refrigerant R flowing into the expansion valve 13 becomes the target temperature, the bypass amount of the refrigerant R to the second heat dissipation heat exchanger 12B is adjusted, and the cooling amount of the refrigerant R in the second heat dissipation heat exchanger 12B is suppressed. As a result, even if the water source temperature of the makeup water W2 is low, the temperature of the liquid refrigerant R flowing into the expansion valve 13 can be kept at a constant temperature that does not become highly supercooled.

(3) The refrigerant temperature adjustment means 50 of the hot water supply system 1 of this embodiment includes a temperature sensor 16 that detects the temperature of the liquid refrigerant R flowing into the expansion valve 13, a pressure sensor 17 that detects the pressure of the liquid refrigerant R flowing into the expansion valve 13, a first bypass line L11 that is connected to the refrigerant circulation line L9 and bypasses the refrigerant R from the second heat dissipation heat exchanger 12B, and a first distribution valve 31 that adjusts the distribution amount of the refrigerant R supplied to the second heat dissipation heat exchanger 12B and the refrigerant R supplied to the first bypass line L11. During operation of the compressor 11, the control means 100 determines the condensation temperature of the gas refrigerant from the pressure detected by the pressure sensor 17, and calculates the degree of subcooling of the liquid refrigerant R by subtracting the temperature detected by the temperature sensor 16 from the condensation temperature, and controls the first distribution valve 31 so that the calculated degree of subcooling becomes a target degree of subcooling.
In this way, by controlling the first distribution valve 31 so that the calculated subcooling degree of the refrigerant R flowing into the expansion valve 13 becomes the target subcooling degree, the bypass amount of the refrigerant R to the second heat dissipation heat exchanger 12B is adjusted, and the cooling amount of the refrigerant R in the second heat dissipation heat exchanger 12B is suppressed. As a result, even if the water source temperature of the makeup water W2 is low, the temperature of the liquid refrigerant R flowing into the expansion valve 13 can be kept at a constant temperature that does not become a highly subcooled state.

Second Embodiment
Next, a second embodiment will be described with reference to the drawings. Fig. 3 is a diagram showing a schematic configuration of a hot water supply system 1 according to the present embodiment. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof may be omitted.

As shown in FIG. 3, the heat pump circuit 10 of this embodiment does not include the first bypass line L11 and the first distribution valve 31.
In the present embodiment, the refrigerant temperature sensor 16, the second bypass line L12, and the second distribution valve 32 constitute a refrigerant temperature adjustment means 50.

As described above, the second bypass line L12 is a line that causes the makeup water W2 to bypass the second heat dissipation heat exchanger 12B.
The second distribution valve 32 is a valve that adjusts the distribution amount of the makeup water W2 to be supplied to the second heat dissipation heat exchanger 12B and the makeup water W2 to be supplied to the second bypass line L12. The second distribution valve 32 in this embodiment is controlled by the distribution valve control unit 130 of the control unit 100.

The distribution valve control unit 130 of this embodiment acquires the temperature detected by the refrigerant temperature sensor 16, and performs control to adjust the valve opening of the second distribution valve 32 constituting the refrigerant temperature adjustment means 50 of this embodiment according to the detected temperature. Specifically, the distribution valve control unit 130 controls the second distribution valve 32 so that the temperature detected by the refrigerant temperature sensor 16 becomes the target temperature while the compressor 11 is in operation. As a more specific control, for example, it is preferable to adopt feedback control in which the refrigerant temperature detected in real time by the refrigerant temperature sensor 16 is used as a feedback value and the valve opening of the second distribution valve 32 is adjusted so that the refrigerant temperature converges to the target temperature. As the feedback control, in addition to proportional control (P control), a calculation algorithm of the manipulated variable that combines this with integral control (I control) and/or differential control (D control) can be adopted.
As a result, the amount of makeup water W2 bypassed to the second heat dissipation heat exchanger 12B is adjusted, and the temperature of the liquid refrigerant R flowing into the expansion valve 13 is adjusted.

With the above configuration, even if the water source temperature of the make-up water is low, the temperature of the liquid refrigerant R flowing into the expansion valve can be kept constant so as not to become highly supercooled. This prevents highly supercooled liquid refrigerant R from being supplied to the heat absorption heat exchanger 14, and prevents the compressor 11 from drawing in refrigerant R in a wet vapor state. This allows the refrigeration cycle to operate optimally while preventing damage to the compressor 11.

Next, a modified example of the second embodiment will be described with reference to the drawings. Figure 4 is a schematic diagram showing the configuration of a hot water supply system according to a modified example of the second embodiment.

As shown in FIG. 4, the heat pump circuit 10 of this modification includes a refrigerant pressure sensor 17 that detects the pressure of the liquid refrigerant R flowing into the expansion valve 13, similar to the modification of the first embodiment. In addition, the control unit 100 of this modification includes a subcooling degree calculation unit 140, similar to the modification of the first embodiment.

In this modified example, the refrigerant pressure sensor 17, the refrigerant temperature sensor 16, the second bypass line L12, and the second distribution valve 32 constitute the refrigerant temperature adjustment means 50.

The distribution valve control unit 130 of this embodiment controls the second distribution valve 32 based on the temperature detected by the refrigerant temperature sensor 16 and the pressure detected by the refrigerant pressure sensor 17. Specifically, the distribution valve control unit 130 of this modified example controls the second distribution valve 32 so that the calculated degree of subcooling calculated by the subcooling degree calculation unit 140 becomes the target degree of subcooling, and adjusts the degree of subcooling of the liquid refrigerant R flowing into the expansion valve 13. Even in this case, it is preferable to employ feedback control in which the calculated degree of subcooling calculated in real time by the subcooling degree calculation unit 140 is used as a feedback value, and the valve opening degree of the second distribution valve 32 is adjusted so that the calculated degree of subcooling converges to the target degree of subcooling.

In this way, the subcooling degree calculation unit 140 accurately calculates the subcooling degree of the liquid refrigerant R flowing into the expansion valve 13, and the distribution valve control unit 130 controls the second distribution valve 32 so that the calculated subcooling degree becomes the target subcooling degree, thereby adjusting the amount of makeup water W2 bypassed to the second heat dissipation heat exchanger 12B and suppressing the amount of cooling of the liquid refrigerant R in the second heat dissipation heat exchanger 12B. As a result, even if the water source temperature of the makeup water W2 is low, the temperature of the liquid refrigerant R flowing into the expansion valve 13 can be kept at a constant temperature that does not become highly subcooled.

In this embodiment, the second distribution valve 32 is not limited to being provided in the second bypass line L12. For example, the second distribution valve 32 may be a three-way valve provided at the branch point where the second bypass line L12 branches off from the make-up water line L2.

The hot water supply system 1 of the second embodiment described above has the following advantages in addition to (1):

(4) The refrigerant temperature adjustment means 50 of the hot water supply system 1 of this embodiment includes a temperature sensor 16 that detects the temperature of the liquid refrigerant R flowing into the expansion valve 13, a second bypass line L12 connected to the make-up water line L2 and bypassing the make-up water W2 from the second heat dissipation heat exchanger 12B, and a second distribution valve 32 that adjusts the distribution amount of the make-up water W2 supplied to the second heat dissipation heat exchanger 12B and the make-up water W2 supplied to the second bypass line L12, and the control means 100 controls the second distribution valve 32 so that the detected temperature of the temperature sensor 16 becomes the target temperature while the compressor 11 is operating.
In this way, by controlling the second distribution valve 32 so that the detected temperature of the refrigerant R flowing into the expansion valve 13 becomes the target temperature, the bypass amount of makeup water W2 for the second heat dissipation heat exchanger 12B is adjusted, and the cooling amount of the refrigerant R in the second heat dissipation heat exchanger 12B is suppressed. As a result, even if the water source temperature of the makeup water W2 is low, the temperature of the liquid refrigerant R flowing into the expansion valve 13 can be kept at a constant temperature that does not become highly supercooled.

(5) The refrigerant temperature adjustment means 50 of the hot water supply system 1 of this embodiment includes a temperature sensor 16 that detects the temperature of the liquid refrigerant R flowing into the expansion valve 13, a pressure sensor 17 that detects the pressure of the liquid refrigerant R flowing into the expansion valve 13, a second bypass line L12 connected to the make-up water line L2 and bypassing the make-up water W2 from the second heat dissipation heat exchanger 12B, and a second distribution valve 32 that adjusts the distribution amount of the make-up water W2 supplied to the second heat dissipation heat exchanger 12B and the make-up water W2 supplied to the second bypass line L12. During operation of the compressor 11, the control means 100 determines the condensation temperature of the gas refrigerant R from the pressure detected by the pressure sensor 17, and calculates the degree of subcooling of the liquid refrigerant R by subtracting the temperature detected by the temperature sensor 16 from the condensation temperature, and controls the second distribution valve 32 so that the calculated degree of subcooling becomes a target degree of subcooling.
In this way, by controlling the second distribution valve 32 so that the calculated subcooling degree of the refrigerant R flowing into the expansion valve 13 becomes the target subcooling degree, the bypass amount of the makeup water W2 for the second heat dissipation heat exchanger 12B is adjusted, and the cooling amount of the refrigerant R in the second heat dissipation heat exchanger 12B is suppressed. As a result, even if the water source temperature of the makeup water W2 is low, the temperature of the liquid refrigerant R flowing into the expansion valve 13 can be kept at a constant temperature that does not become a highly subcooled state.

Third Embodiment
Next, a third embodiment will be described with reference to the drawings. Fig. 5 is a diagram showing a schematic configuration of a hot water supply system 1 according to the present embodiment. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof may be omitted.

5, the heat pump circuit 10 of this embodiment does not include the first bypass line L11 and the first distribution valve 31. Instead, a third bypass line L13 and a third distribution valve 33 are provided.
In the present embodiment, the refrigerant temperature sensor 16, the third bypass line L13, and the third distribution valve 33 constitute a refrigerant temperature adjustment means 50.

The third bypass line L13 is a line that allows the refrigerant R to bypass the first heat dissipation heat exchanger 12A.
The third distribution valve 33 is a valve that adjusts the distribution amount of the refrigerant R supplied to the first heat dissipation heat exchanger 12A and the refrigerant R supplied to the third bypass line L13. The third distribution valve 33 in this embodiment is controlled by the distribution valve control unit 130 of the control unit 100.

The distribution valve control unit 130 of this embodiment acquires the temperature detected by the refrigerant temperature sensor 16, and performs control to adjust the valve opening of the third distribution valve 33 constituting the refrigerant temperature adjustment means 50 of this embodiment in accordance with the detected temperature. Specifically, the distribution valve control unit 130 controls the third distribution valve 33 so that the temperature detected by the refrigerant temperature sensor 16 becomes the target temperature while the compressor 11 is in operation. As a more specific control, for example, it is preferable to adopt feedback control in which the refrigerant temperature detected in real time by the refrigerant temperature sensor 16 is used as a feedback value and the valve opening of the third distribution valve 33 is adjusted so that the refrigerant temperature converges to the target temperature. As the feedback control, in addition to proportional control (P control), a calculation algorithm of the manipulated variable that combines this with integral control (I control) and/or differential control (D control) can be adopted.
This adjusts the amount of refrigerant R bypassed from the first heat dissipation heat exchanger 12A, and suppresses the amount of cooling of the refrigerant R in the first heat dissipation heat exchanger 12A.
As a result of being bypassed, the refrigerant R that is not condensed and liquefied in the first heat dissipation heat exchanger 12A is condensed and liquefied in the second heat dissipation heat exchanger 12B.

With the above configuration, even when the hot water storage temperature is set to a low temperature, the temperature of the liquid refrigerant R flowing into the expansion valve 13 can be kept constant so as not to become highly supercooled. This prevents highly supercooled liquid refrigerant R from being supplied to the heat absorption heat exchanger 14, and prevents the compressor 11 from drawing in refrigerant R in a wet vapor state. This allows the refrigeration cycle to operate optimally while preventing damage to the compressor 11.

Next, a modified example of the third embodiment will be described with reference to the drawings. Figure 6 is a schematic diagram showing the configuration of a hot water supply system according to a modified example of the third embodiment.

As shown in FIG. 6, the heat pump circuit 10 of this modification includes a refrigerant pressure sensor 17 that detects the pressure of the liquid refrigerant R flowing into the expansion valve 13, similar to the modification of the first embodiment. In addition, the control unit 100 of this modification includes a subcooling degree calculation unit 140, similar to the modification of the first embodiment.

In this modified example, the refrigerant pressure sensor 17, the refrigerant temperature sensor 16, the third bypass line L13, and the third distribution valve 33 constitute the refrigerant temperature adjustment means 50.

The distribution valve control unit 130 of this embodiment controls the third distribution valve 33 based on the temperature detected by the refrigerant temperature sensor 16 and the pressure detected by the refrigerant pressure sensor 17. Specifically, the distribution valve control unit 130 of this modified example controls the third distribution valve 33 so that the calculated degree of subcooling calculated by the subcooling degree calculation unit 140 becomes the target degree of subcooling, and adjusts the degree of subcooling of the liquid refrigerant R flowing into the expansion valve 13. Even in this case, it is preferable to employ feedback control in which the calculated degree of subcooling calculated in real time by the subcooling degree calculation unit 140 is used as a feedback value, and the valve opening degree of the third distribution valve 33 is adjusted so that the calculated degree of subcooling converges to the target degree of subcooling.

In this way, the subcooling degree calculation unit 140 accurately calculates the subcooling degree of the liquid refrigerant R flowing into the expansion valve 13, and the distribution valve control unit 130 controls the third distribution valve 33 so that the calculated subcooling degree becomes the target subcooling degree, thereby adjusting the amount of refrigerant R bypassed to the first heat dissipation heat exchanger 12A and suppressing the amount of cooling of refrigerant R in the first heat dissipation heat exchanger 12A. As a result, even when the hot water storage temperature is set to a low temperature, the temperature of the liquid refrigerant R flowing into the expansion valve 13 can be kept at a constant temperature that does not become highly subcooled.

In this embodiment, the third distribution valve 33 is not limited to being provided in the third bypass line L13. For example, the third distribution valve 33 may be a three-way valve provided at the branch point where the third bypass line L13 branches off from the refrigerant circulation line L9.

The hot water supply system 1 of the third embodiment described above has the following advantages in addition to (1):

(6) The refrigerant temperature adjustment means 50 of the hot water supply system 1 of this embodiment includes a temperature sensor 16 that detects the temperature of the liquid refrigerant R flowing into the expansion valve 13, a third bypass line L13 connected to the refrigerant circulation line L9 and bypassing the refrigerant R from the first heat dissipation heat exchanger 12A, and a third distribution valve 33 that adjusts the distribution amount of the refrigerant R supplied to the first heat dissipation heat exchanger 12A and the refrigerant R supplied to the third bypass line L13, and the control means 100 controls the third distribution valve 33 so that the detected temperature of the temperature sensor 16 becomes the target temperature while the compressor 11 is operating.
In this way, by controlling the third distribution valve 33 so that the detected temperature of the refrigerant R flowing into the expansion valve 13 becomes the target temperature, the bypass amount of the refrigerant R to the first heat dissipation heat exchanger 12A is adjusted, and the cooling amount of the refrigerant R in the first heat dissipation heat exchanger 12A is suppressed. As a result, even when the hot water storage temperature is set to a low temperature, the temperature of the liquid refrigerant R flowing into the expansion valve 13 can be kept at a constant temperature that does not become highly supercooled.

(7) The refrigerant temperature adjustment means 50 of the hot water supply system 1 of this embodiment includes a temperature sensor 16 that detects the temperature of the liquid refrigerant R flowing into the expansion valve 13, a pressure sensor 17 that detects the pressure of the liquid refrigerant R flowing into the expansion valve 13, a third bypass line L13 that is connected to the refrigerant circulation line L9 and bypasses the refrigerant R from the first heat dissipation heat exchanger 12A, and a third distribution valve 33 that adjusts the distribution amount of the refrigerant R supplied to the first heat dissipation heat exchanger 12A and the refrigerant R supplied to the third bypass line L13. During operation of the compressor 11, the control means 100 determines the condensation temperature of the gas refrigerant R from the pressure detected by the pressure sensor 17, and calculates the degree of subcooling of the liquid refrigerant R by subtracting the temperature detected by the temperature sensor 16 from the condensation temperature, and controls the third distribution valve 33 so that the calculated degree of subcooling becomes a target degree of subcooling.
In this way, by controlling the third distribution valve 33 so that the calculated degree of subcooling of the refrigerant R flowing into the expansion valve 13 becomes the target degree of subcooling, the amount of refrigerant R bypassed to the first heat dissipation heat exchanger 12A is adjusted, and the amount of cooling of the refrigerant R in the first heat dissipation heat exchanger 12A is suppressed. As a result, even when the hot water storage temperature is set to a low temperature, the temperature of the liquid refrigerant R flowing into the expansion valve 13 can be kept at a constant temperature that does not become highly subcooled.

Fourth Embodiment
Next, a fourth embodiment will be described with reference to the drawings. Fig. 7 is a diagram showing a schematic configuration of a hot water supply system 1 according to the present embodiment. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof may be omitted.

7, the heat pump circuit 10 of this embodiment does not include the first bypass line L11 and the first distribution valve 31. Instead, a fourth bypass line L14 and a fourth distribution valve 34 are provided.
In the present embodiment, the refrigerant temperature sensor 16, the fourth bypass line L14, and the fourth distribution valve 34 constitute a refrigerant temperature adjustment means 50.

The fourth bypass line L14 is a line that causes the circulating water W1 to bypass the first heat dissipation heat exchanger 12A.
The fourth distribution valve 34 is a valve that adjusts the distribution amount of the circulating water W1 to be supplied to the first heat dissipation heat exchanger 12A and the circulating water W1 to be supplied to the fourth bypass line L14. The fourth distribution valve 34 in this embodiment is controlled by the distribution valve control unit 130 of the control unit 100.

The distribution valve control unit 130 of this embodiment acquires the temperature detected by the refrigerant temperature sensor 16, and performs control to adjust the valve opening of the fourth distribution valve 34 constituting the refrigerant temperature adjustment means 50 of this embodiment in accordance with the detected temperature. Specifically, the distribution valve control unit 130 controls the fourth distribution valve 34 so that the temperature detected by the refrigerant temperature sensor 16 becomes the target temperature while the compressor 11 is in operation. As a more specific control, for example, it is preferable to adopt feedback control in which the refrigerant temperature detected in real time by the refrigerant temperature sensor 16 is used as a feedback value and the valve opening of the fourth distribution valve 34 is adjusted so that the refrigerant temperature converges to the target temperature. As the feedback control, in addition to proportional control (P control), a calculation algorithm of the manipulated variable that combines this with integral control (I control) and/or differential control (D control) can be adopted.
This adjusts the amount of circulating water W1 bypassed to the first heat dissipation heat exchanger 12A, and adjusts the temperature of the liquid refrigerant R flowing into the expansion valve 13.
As a result of being bypassed, the refrigerant R that is not condensed and liquefied in the first heat dissipation heat exchanger 12A is condensed and liquefied in the second heat dissipation heat exchanger 12B.

With the above configuration, even if the water source temperature of the make-up water is low, the temperature of the liquid refrigerant R flowing into the expansion valve 13 can be kept constant so as not to become highly supercooled. This prevents highly supercooled liquid refrigerant R from being supplied to the heat absorption heat exchanger 14, and prevents the compressor 11 from drawing in refrigerant R in a wet vapor state. This allows the refrigeration cycle to operate optimally while preventing damage to the compressor 11.

Next, a modified example of the fourth embodiment will be described with reference to the drawings. FIG. 8 is a diagram showing a schematic configuration of a hot water supply system according to a modified example of the fourth embodiment.

As shown in FIG. 8, the heat pump circuit 10 of this modification includes a refrigerant pressure sensor 17 that detects the pressure of the liquid refrigerant R flowing into the expansion valve 13, similar to the modification of the first embodiment. In addition, the control unit 100 of this modification includes a subcooling degree calculation unit 140, similar to the modification of the first embodiment.

In this modified example, the refrigerant pressure sensor 17, the refrigerant temperature sensor 16, the fourth bypass line L14, and the fourth distribution valve 34 constitute the refrigerant temperature adjustment means 50.

The distribution valve control unit 130 of this embodiment controls the fourth distribution valve 34 based on the temperature detected by the refrigerant temperature sensor 16 and the pressure detected by the refrigerant pressure sensor 17. Specifically, the distribution valve control unit 130 of this modified example controls the fourth distribution valve 34 so that the calculated degree of subcooling calculated by the subcooling degree calculation unit 140 becomes the target degree of subcooling, and adjusts the degree of subcooling of the liquid refrigerant R flowing into the expansion valve 13. Even in this case, it is preferable to employ feedback control in which the calculated degree of subcooling calculated in real time by the subcooling degree calculation unit 140 is used as a feedback value, and the valve opening degree of the fourth distribution valve 34 is adjusted so that the calculated degree of subcooling converges to the target degree of subcooling.

In this way, the subcooling degree calculation unit 140 accurately calculates the subcooling degree of the liquid refrigerant R flowing into the expansion valve 13, and the distribution valve control unit 130 controls the fourth distribution valve 34 so that the calculated subcooling degree becomes the target subcooling degree, thereby adjusting the amount of makeup water W2 bypassed to the first heat dissipation heat exchanger 12A and suppressing the amount of cooling of the refrigerant R in the first heat dissipation heat exchanger 12A. As a result, even if the water source temperature of the makeup water W2 is low, the temperature of the liquid refrigerant R flowing into the expansion valve 13 can be kept at a constant temperature that does not become highly subcooled.

In this embodiment, the fourth distribution valve 34 is not limited to being provided in the fourth bypass line L14. For example, the fourth distribution valve 34 may be a three-way valve provided at the branch point where the fourth bypass line L14 branches off from the water circulation line L1.

The hot water supply system 1 of the fourth embodiment described above has the following advantages in addition to (1):

(8) The refrigerant temperature adjustment means 50 of the hot water supply system 1 of this embodiment includes a temperature sensor 16 that detects the temperature of the liquid refrigerant R flowing into the expansion valve 13, a fourth bypass line L14 connected to the water circulation line L1 and bypassing the circulating water W1 from the first heat dissipation heat exchanger 12A, and a fourth distribution valve 34 that adjusts the distribution amount of the circulating water W1 supplied to the first heat dissipation heat exchanger 12A and the circulating water W1 supplied to the fourth bypass line L14, and the control means 100 controls the fourth distribution valve 34 so that the detected temperature of the temperature sensor 16 becomes the target temperature while the compressor 11 is operating.
In this way, by controlling the fourth distribution valve 34 so that the detected temperature of the liquid refrigerant R flowing into the expansion valve 13 becomes the target temperature, the bypass amount of the circulating water W1 for the first heat dissipation heat exchanger 12A is adjusted, and the cooling amount of the refrigerant R in the first heat dissipation heat exchanger 12A is suppressed. As a result, even when the hot water storage temperature is set to a low temperature, the temperature of the liquid refrigerant R flowing into the expansion valve 13 can be kept at a constant temperature that does not become highly supercooled.

(9) The refrigerant temperature adjustment means 50 of the hot water supply system 1 of this embodiment includes a temperature sensor 16 that detects the temperature of the liquid refrigerant R flowing into the expansion valve 13, a pressure sensor 17 that detects the pressure of the liquid refrigerant R flowing into the expansion valve 13, a fourth bypass line L14 connected to the water circulation line L1 and bypassing the circulating water W1 from the first heat dissipation heat exchanger 12A, and a fourth distribution valve 34 that adjusts the distribution amount of the circulating water W1 supplied to the first heat dissipation heat exchanger 12A and the circulating water W1 supplied to the fourth bypass line L14. During operation of the compressor 11, the control means 100 determines the condensation temperature of the gas refrigerant from the pressure detected by the pressure sensor 17, and calculates the degree of subcooling of the liquid refrigerant R by subtracting the temperature detected by the temperature sensor 16 from the condensation temperature, and controls the fourth distribution valve 34 so that the calculated degree of subcooling becomes a target degree of subcooling.
In this way, by controlling the fourth distribution valve 34 so that the calculated degree of subcooling of the refrigerant R flowing into the expansion valve 13 becomes the target degree of subcooling, the amount of circulating water W1 bypassed to the first heat dissipation heat exchanger 12A is adjusted, and the amount of cooling of the refrigerant R in the first heat dissipation heat exchanger 12A is suppressed. As a result, even when the hot water storage temperature is set to a low temperature, the temperature of the liquid refrigerant R flowing into the expansion valve 13 can be kept at a constant temperature that does not become highly subcooled.

Although the above describes each preferred embodiment of the hot water supply system of the present invention, the present invention is not limited to the above-mentioned embodiments and can be modified as appropriate. It is also possible to combine multiple embodiments.

1 Hot water supply system 10 Heat pump circuit 11 Compressor 12A First heat dissipation heat exchanger (condenser)
12B Second heat dissipation heat exchanger (supercooler)
13 Expansion valve 14 Heat absorbing heat exchanger (evaporator)
16 Refrigerant temperature sensor (temperature sensor)
17 Refrigerant pressure sensor (pressure sensor)
21 Water circulation pump 22 First temperature sensor 25 Make-up water valve 26 Second temperature sensor 31 First distribution valve 32 Second distribution valve 33 Third distribution valve 34 Fourth distribution valve 60 Hot water tank 61 Hot water temperature sensor 62 Water level sensor 100 Control unit (control means)
110 Water circulation pump control unit 120 Make-up water valve control unit 130 Distribution valve control unit 140 Subcooling degree calculation unit L1 Water circulation line L2 Make-up water line L4 Hot water supply line L9 Refrigerant circulation line L11 First bypass line L12 Second bypass line L13 Third bypass line L14 Fourth bypass line W1 Circulating water W2 Make-up water W3 Reservoir water W4 Hot water supply R Refrigerant (gas refrigerant, liquid refrigerant)

Claims (9)

a vapor compression heat pump circuit in which a compressor, a first heat dissipation heat exchanger, a second heat dissipation heat exchanger, an expansion valve, and a heat absorption heat exchanger are connected in a ring shape by a refrigerant circulation line, and heat is extracted from the first heat dissipation heat exchanger and/or the second heat dissipation heat exchanger by driving the compressor;
A hot water storage tank for storing makeup water;
a water circulation line for circulating the water stored in the hot water storage tank to the first heat dissipation heat exchanger;
a make-up water line that supplies make-up water to the hot water storage tank while circulating the make-up water through the second heat dissipation heat exchanger;
a refrigerant temperature adjusting means for adjusting the temperature of the liquid refrigerant flowing into the expansion valve;
A control means for controlling the refrigerant temperature adjustment means ,
The refrigerant temperature adjustment means is
a bypass line for bypassing a refrigerant or circulating water from the first heat dissipation heat exchanger, or for bypassing a refrigerant or makeup water from the second heat dissipation heat exchanger;
and a distribution valve for adjusting the distribution amount of the refrigerant, circulating water, or make-up water supplied to the bypass line . The refrigerant temperature adjustment means is
A temperature sensor that detects the temperature of the liquid refrigerant flowing into the expansion valve;
a first bypass line connected to the refrigerant circulation line and allowing the refrigerant to bypass the second heat dissipation heat exchanger;
a first distribution valve that adjusts a distribution amount of the refrigerant to be supplied to the second heat dissipation heat exchanger and the refrigerant to be supplied to the first bypass line,
The hot water supply system according to claim 1 , wherein the control means controls the first distribution valve so that the temperature detected by the temperature sensor becomes a target temperature while the compressor is in operation. The refrigerant temperature adjustment means is
A temperature sensor that detects the temperature of the liquid refrigerant flowing into the expansion valve;
a pressure sensor that detects the pressure of the liquid refrigerant flowing into the expansion valve;
a first bypass line connected to the refrigerant circulation line and allowing the refrigerant to bypass the second heat dissipation heat exchanger;
a first distribution valve that adjusts a distribution amount of the refrigerant to be supplied to the second heat dissipation heat exchanger and the refrigerant to be supplied to the first bypass line,
2. The hot water supply system of claim 1, wherein the control means, while the compressor is operating, determines a condensation temperature of the gas refrigerant from the pressure detected by the pressure sensor, calculates a degree of subcooling of the liquid refrigerant by subtracting the temperature detected by the temperature sensor from the condensation temperature, and controls the first distribution valve so that the calculated degree of subcooling becomes a target degree of subcooling. The refrigerant temperature adjustment means is
A temperature sensor that detects the temperature of the liquid refrigerant flowing into the expansion valve;
a second bypass line connected to the makeup water line and allowing the makeup water to bypass the second heat dissipation heat exchanger;
a second distribution valve that adjusts a distribution amount of makeup water to be supplied to the second heat dissipation heat exchanger and a distribution amount of makeup water to be supplied to the second bypass line,
The hot water supply system according to claim 1 , wherein the control means controls the second distribution valve so that the temperature detected by the temperature sensor becomes a target temperature while the compressor is in operation. The refrigerant temperature adjustment means is
A temperature sensor that detects the temperature of the liquid refrigerant flowing into the expansion valve;
A pressure sensor that detects the pressure of the liquid refrigerant flowing into the expansion valve;
a second bypass line connected to the makeup water line and allowing the makeup water to bypass the second heat dissipation heat exchanger;
a second distribution valve that adjusts a distribution amount of makeup water to be supplied to the second heat dissipation heat exchanger and a distribution amount of makeup water to be supplied to the second bypass line,
2. The hot water supply system of claim 1, wherein the control means, while the compressor is operating, determines a condensation temperature of the gas refrigerant from the pressure detected by the pressure sensor, calculates a degree of subcooling of the liquid refrigerant by subtracting the temperature detected by the temperature sensor from the condensation temperature, and controls the second distribution valve so that the calculated degree of subcooling becomes a target degree of subcooling. The refrigerant temperature adjustment means is
A temperature sensor that detects the temperature of the liquid refrigerant flowing into the expansion valve;
a third bypass line connected to the refrigerant circulation line for bypassing the refrigerant from the first heat dissipation heat exchanger;
a third distribution valve that adjusts a distribution amount of the refrigerant to be supplied to the first heat dissipation heat exchanger and the refrigerant to be supplied to the third bypass line,
The hot water supply system according to claim 1 , wherein the control means controls the third distribution valve so that the temperature detected by the temperature sensor becomes a target temperature while the compressor is in operation. The refrigerant temperature adjustment means is
A temperature sensor that detects the temperature of the liquid refrigerant flowing into the expansion valve;
A pressure sensor that detects the pressure of the liquid refrigerant flowing into the expansion valve;
a third bypass line connected to the refrigerant circulation line for bypassing the refrigerant from the first heat dissipation heat exchanger;
a third distribution valve that adjusts a distribution amount of the refrigerant to be supplied to the first heat dissipation heat exchanger and the refrigerant to be supplied to the third bypass line,
2. The hot water supply system of claim 1, wherein the control means, while the compressor is operating, determines a condensation temperature of the gas refrigerant from the pressure detected by the pressure sensor, calculates a degree of subcooling of the liquid refrigerant by subtracting the temperature detected by the temperature sensor from the condensation temperature, and controls the third distribution valve so that the calculated degree of subcooling becomes a target degree of subcooling. The refrigerant temperature adjustment means is
A temperature sensor that detects the temperature of the liquid refrigerant flowing into the expansion valve;
a fourth bypass line connected to the water circulation line for bypassing the circulating water from the first heat dissipation heat exchanger;
a fourth distribution valve that adjusts a distribution amount of the circulating water supplied to the first heat dissipation heat exchanger and the circulating water supplied to the fourth bypass line,
The hot water supply system according to claim 1 , wherein the control means controls the fourth distribution valve so that the temperature detected by the temperature sensor becomes a target temperature while the compressor is in operation. The refrigerant temperature adjustment means is
A temperature sensor that detects the temperature of the liquid refrigerant flowing into the expansion valve;
a pressure sensor that detects the pressure of the liquid refrigerant flowing into the expansion valve;
a fourth bypass line connected to the water circulation line for bypassing the circulating water from the first heat dissipation heat exchanger;
a fourth distribution valve that adjusts a distribution amount of the circulating water supplied to the first heat dissipation heat exchanger and the circulating water supplied to the fourth bypass line,
2. The hot water supply system of claim 1, wherein the control means, while the compressor is operating, determines a condensation temperature of the gas refrigerant from the pressure detected by the pressure sensor, calculates a degree of subcooling of the liquid refrigerant by subtracting the temperature detected by the temperature sensor from the condensation temperature, and controls the fourth distribution valve so that the calculated degree of subcooling becomes a target degree of subcooling.