JP2017215088A - Heat pump type water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat pump type water heater capable of resolving such inconvenience that freezing prevention operation is not executed by a backflow phenomenon from a hot water storage tank, without increasing the number of components.SOLUTION: A controller 70 is configured to, when a temperature of hot water to be supplied of a hot water supply circuit 20 positioned in a heating unit 50 lowers to a predetermined value or less, execute freezing prevention operation for operating a water pump 23. In a state where the water pump 23 stops, when the temperature of hot water to be supplied of the hot water supply circuit 20 positioned in the heating unit 50 rises, the water pump 23 is operated.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a heat pump hot water supply apparatus that heats hot water in a hot water storage tank using a heat pump circuit.

  Conventionally, as this type of heat pump type hot water supply device, a tank unit with a hot water storage tank for storing hot water supply water, and hot water in the hot water storage tank are taken out from the lower part of the hot water storage tank by a pump, and water heat exchange is performed through an inflow pipe. And a heating unit with a built-in heat pump circuit that heats the hot water water that flows through the water heat exchanger of the hot water supply circuit using a refrigerant. Are known (for example, see Patent Document 1).

  In addition, the inflow pipe and the outflow pipe of the hot water supply circuit described above are normally insulated. However, in the case where the insulation is not sufficient or in an environment where the outside air temperature is extremely low in winter, the inflow pipe and outflow of the hot water supply circuit described above. There was a case where the hot water supply water in the pipe was frozen. If the hot water supply water freezes in the inflow pipe or outflow pipe, the hot water supply circuit cannot be circulated even if the pump is operated. As a result, frost grows in the evaporator in the heating unit. Inconveniences such as being damaged by hitting.

  Therefore, a water temperature sensor (water temperature detection means) for detecting the temperature of hot water on the water inlet side of the water heat exchanger provided in the heating unit conventionally has a predetermined low temperature (however, a predetermined value higher than the freezing point). If detected, a freeze prevention operation was performed in which the pump was operated to circulate the hot water supply water (hot water) in the hot water storage tank in the hot water supply circuit (see, for example, Patent Document 2).

JP2013-76512A JP 2014-196849 A

  Here, the heating unit is often installed on the roof of the residence, and the tank unit is often installed in the basement of the residence or on the ground outside the residence. In such an installation state, the heating unit is positioned higher than the tank unit, so if the temperature of hot water in the outflow pipe decreases due to a drop in the outside air temperature in winter, etc. Due to the difference, a hot water supply water (hot water) in the upper part of the hot water storage tank flows back to the outflow pipe.

  When such a backflow phenomenon occurs, the temperature of the outflow pipe rises, and eventually the temperature of the hot water supply circuit located in the heating unit also rises. And since the incoming water temperature sensor which detects the temperature of the hot water supply water of the incoming side of a water heat exchanger also cannot detect the predetermined value mentioned above, freezing prevention operation is not performed.

  However, since the temperature does not rise up to the inflow pipe positioned between the heating unit and the tank unit, the hot water supply water in the inflow pipe originally having a low temperature freezes, and the circulation of the hot water supply water in the hot water supply circuit is hindered. Inconvenience occurred. As a means for preventing such a backflow phenomenon, it is conceivable to attach a check valve (the hot water storage tank direction is the forward direction) or the like to the outflow pipe. However, the number of parts increases, leading to an increase in cost.

  The present invention has been made to solve the conventional technical problems, and is a heat pump type that eliminates the inconvenience that the anti-freezing operation is not performed due to the reverse flow phenomenon from the hot water storage tank without increasing the number of parts. It aims at providing a hot-water supply apparatus.

  The heat pump hot water supply apparatus of the present invention is provided with a heating unit provided with a heat pump circuit formed by connecting a compressor, a water heat exchanger, a decompression device, and an evaporator, and a hot water storage tank for storing hot water supply water. The tank unit, hot water supply water in the hot water storage tank is taken out from the lower part of the hot water storage tank by the water pump, distributed to the water heat exchanger, and then supplied to the upper part of the hot water storage tank, and the water pump and compressor are operated. And a control device that performs a boiling operation for heating the hot-water supply water that circulates through the water heat exchanger with a refrigerant, wherein the control device is a hot-water supply water for a hot-water supply circuit located in the heating unit. When the temperature of the hot water drops below a predetermined value, the anti-freezing operation for operating the water pump is performed, and the hot water supply located in the heating unit is stopped with the water pump stopped. If the temperature of the water for hot water supply of the road is increased, characterized by operating the water pump.

  In the heat pump hot water supply apparatus according to the second aspect of the present invention, in the above invention, the control device increases after the temperature of the hot water supply water in the hot water supply circuit located in the heating unit is once lowered while the water pump is stopped. When it turns, it is characterized by operating a water pump.

  According to a third aspect of the present invention, there is provided the heat pump type hot water supply apparatus according to each of the above inventions, wherein the control device is configured so that the temperature of the hot water for the hot water supply circuit located in the heating unit is predetermined within a predetermined time in a state where the water pump is stopped. The water pump is operated when it rises above the value.

  According to a fourth aspect of the present invention, there is provided the heat pump type hot water supply apparatus in each of the above inventions, wherein the control device is a hot water supply circuit located in the heating unit in a state where the outside air temperature is not more than a predetermined value and the water pump is stopped. When the temperature of the hot water supply water rises, the water pump is operated.

  In the heat pump type hot water supply apparatus of the invention of claim 5, in each of the above inventions, the temperature of the hot water supply water on the water inlet side of the water heat exchanger is a predetermined low value even if the control device is operated for a predetermined time in the freeze prevention operation. In this case, the compressor is operated.

  The heat pump type hot water supply apparatus of the invention of claim 6 is the anti-freezing operation when the temperature of the hot water supply water in the hot water supply circuit located in the heating unit rises while the water pump is stopped in the control device. It is characterized by performing.

  In the heat pump type hot water supply apparatus of the invention of claim 7, the temperature of the hot water in the hot water supply circuit located in the heating unit in each of the above inventions is the temperature of the hot water on the inlet side of the water heat exchanger or the water heat exchanger It is the temperature of the hot water supply water of the tapping side.

  The heat pump hot water supply apparatus according to an eighth aspect of the present invention is characterized in that, in each of the above inventions, the heating unit is disposed at a position higher than the tank unit.

  The heat pump type hot water supply apparatus of the invention of claim 9 is the inflow pipe for taking out the hot water in the hot water storage tank from the lower part of the hot water storage tank, the hot water supply circuit being located between the heating unit and the tank unit in each of the above inventions, , Having an outflow pipe for flowing hot water after flowing through the water heat exchanger into the upper part of the hot water storage tank, and at least a part of the inflow pipe and the outflow pipe are arranged at a position higher than the tank unit. It is characterized by.

  According to the present invention, a compressor, a water heat exchanger, a decompression device, a heating unit provided with a heat pump circuit formed by connecting an evaporator, and a tank unit provided with a hot water storage tank for storing hot water supply water, The hot water supply water in the hot water storage tank is taken out from the lower part of the hot water storage tank by the water pump, circulated to the water heat exchanger, and then flows into the upper part of the hot water storage tank, and the water pump and the compressor are operated. A heat pump type hot water supply apparatus comprising: a control device that executes a boiling operation for heating hot water flowing through the water heat exchanger with a refrigerant; and the temperature of the hot water in the hot water supply circuit located in the heating unit. For example, when the temperature of hot water on the incoming side of the water heat exchanger as in the invention of claim 7 or the temperature of hot water on the outlet side of the water heat exchanger falls below a predetermined value, The water pump is operated when the temperature of the hot water in the hot water supply circuit located in the heating unit rises while the water pump is stopped when the antifreezing operation for operating the pump is performed. When a reverse flow phenomenon of hot hot water supply water (hot water) from the hot water storage tank occurs in the hot water supply circuit, the water pump can be operated to circulate the hot water supply water in the hot water supply circuit.

  Thus, for example, when the heating unit is arranged at a position higher than the tank unit as in the invention of claim 8, or at least a part of the inflow pipe and outflow pipe of the hot water supply circuit is higher than the tank unit as in the invention of claim 9. The anti-freezing operation is not executed due to the reverse flow phenomenon that is likely to occur when it is disposed at the position, and the inconvenience that the hot water supply circuit freezes can be avoided. Moreover, since it is not necessary to provide a check valve or the like in the hot water supply circuit, it is possible to prevent an increase in cost due to an increase in the number of parts.

  According to the invention of claim 2, in addition to the above-mentioned invention, the control device increases after the temperature of the hot water supply water in the hot water supply circuit located in the heating unit is temporarily lowered while the water pump is stopped. In this case, since the water pump is operated, it is possible to accurately determine the occurrence of the backflow phenomenon that occurs after the water pump is stopped.

  According to the invention of claim 3, in addition to the above inventions, the temperature of the hot water supply water in the hot water supply circuit located in the heating unit is within a predetermined time in a state where the water pump is stopped. Since the water pump is operated when it rises above a predetermined value, the occurrence of the backflow phenomenon can be determined more accurately.

  According to the invention of claim 4, in addition to each of the above inventions, the control device includes a hot water supply circuit located in the heating unit in a state where the outside air temperature is equal to or lower than a predetermined value and the water pump is stopped. Since the water pump is operated when the temperature of hot water for hot water rises, it is possible to accurately detect the reverse flow phenomenon in a low outside air temperature environment and to avoid unnecessary operation of the water pump. .

  If the temperature of the hot water supply water on the water inlet side of the water heat exchanger is a predetermined low value even if the water pump is operated for a predetermined time in the freeze prevention operation, the control device as in the invention of claim 5 However, it is possible to more smoothly realize prevention of freezing of the hot water supply circuit. However, as in the invention of claim 6, the control device is installed in the heating unit while the water pump is stopped. If the freeze prevention operation is executed even when the temperature of the hot water supply water in the hot water supply circuit is increased, the hot water supply circuit can be more reliably prevented from freezing when a reverse flow phenomenon occurs. .

It is a lineblock diagram of the heat pump type hot-water supply device as one embodiment to which the present invention is applied. It is a flowchart of the boiling operation which the control apparatus of the heat pump type hot-water supply apparatus of FIG. 1 performs. It is a flowchart of the freeze prevention driving | operation (backflow determination is included) which the control apparatus of the heat pump type hot-water supply apparatus of FIG. 1 performs.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(1) Heat pump type hot water supply device 1
The heat pump type hot water supply apparatus 1 of the embodiment includes a hot water storage tank 10 that stores hot water supply water, a hot water supply circuit 20 that distributes hot water supply water in the hot water storage tank 10, a heat pump circuit 30 that distributes refrigerant, and hot water supply water in the hot water supply circuit 20. A water heat exchanger 40 for exchanging heat with the refrigerant of the heat pump circuit 30 is provided, and the hot water supply water flowing through the hot water supply circuit 20 is heated by the refrigerant of the heat pump circuit 30.

(2) Hot water storage tank 10
The hot water storage tank 10 is composed of a vertically long sealed container, and is installed on the ground outside the residence or in the basement. A water supply pipe 11 for introducing tap water is connected to the lower part of the hot water storage tank 10. The water supply pipe 11 is provided with a pressure reducing valve 12. A hot water supply pipe 13 for supplying hot water in the hot water storage tank 10 to a hot water supply destination in the residence is connected to the upper part of the hot water storage tank 10, and the hot water supply pipe 13 and the water supply pipe 11 are connected via a bypass pipe 14. .

  A mixing valve 15 is provided between the hot water supply pipe 13 and the bypass pipe 14, and the mixing valve 15 is configured to mix the hot water in the hot water storage tank 10 and the water from the water supply pipe 11 and distribute them to the hot water supply pipe 13. Has been. Further, the hot water storage tank 10 is provided with a hot water storage temperature sensor 16 for detecting the temperature of hot water supply water in the hot water storage tank 10, and this hot water storage temperature sensor 16 is a predetermined location in the vertical direction of the hot water storage tank 10 (substantially the center in the embodiment). Is attached.

(3) Hot water supply circuit 20
The hot water supply circuit 20 includes an inflow pipe 21 connected between a lower portion of the hot water storage tank 10 and an inflow side connection port 52 attached to an outer surface of an exterior case 51 of a heating unit 50 described later, a water pump 23, A water inlet pipe 22 connected between the suction side of the water pump 23 and the connection port 52, a water outlet pipe 24 connected between the discharge side of the water pump 23 and the inflow side of the water heat exchanger 40, water An outlet pipe 26 connected between the outflow side of the heat exchanger 40 and an outflow side connection port 54 attached to the outer surface of the outer case 51, and an outflow pipe connected to the connection port 54 and the upper part of the hot water storage tank 10. 27, and a water inlet temperature sensor 28 for detecting the temperature of hot water supplied from the lower part of the hot water storage tank 10 (the temperature of hot water on the incoming side of the water heat exchanger 40) is provided in the incoming water pipe 22. The hot water pipe 26 has a hydrothermal exchange. Hot water temperature sensor 29 is provided for detecting the temperature of the hot water supply water having passed through the 40 (temperature of the hot water supply water for hot water side of the water heat exchanger 40).

  The hot water supply circuit 20 is provided with a drain plug 18 for draining water inside. This drain plug 18 is also attached to the outer surface of the outer case 51 of the heating unit 50, and is connected to the inlet pipe 22 through the drain pipe 19. Incidentally, 52A and 54A are air vent valves provided at the connection ports 52 and 54, and 25 is a filter provided at the water inlet pipe 22. Reference numeral 55 denotes an outside air temperature sensor that is attached to the exterior case 51 and detects the outside air temperature.

(4) Heat pump circuit 30
The heat pump circuit 30 includes a compressor 31, the water heat exchanger 40, an expansion valve 33 as a decompression device, and an evaporator 32 to form a refrigerant circuit. The compressor 31, the water heat exchanger 40, the expansion valve 33, the evaporator 32, and the compressor 31 are configured to circulate the refrigerant in this order. The refrigerant used in the heat pump circuit 30 is a natural refrigerant such as CO ₂ (carbon dioxide). Reference numeral 34 denotes a blower for ventilating the outside air to the evaporator 32.

  The water heat exchanger 40 is composed of a double-pipe heat exchanger having a refrigerant flow passage 41 and a water flow passage 42. The heat pump circuit 30 is connected to the refrigerant flow passage 41, and the water flow passage 42 is connected to the water flow passage 42. A water outlet pipe 24 and a hot water outlet pipe 26 of the hot water supply circuit 20 are connected.

  The heat pump type hot water supply apparatus 1 of the embodiment includes a water pump 23, a heat pump circuit 30, a water heat exchanger 40, an incoming water temperature sensor 28, a hot water temperature sensor 29, and the like, the hot water storage tank 10, The tank unit 60 provided with the hot water storage temperature sensor 16 is provided, and the heating unit 50 and the tank unit 60 are connected to the inflow pipe 21 of the hot water supply circuit 20 at the connection ports 52 and 54 attached to the outer case 51 of the heating unit 50. And through an outflow pipe 27.

  In many cases, the heating unit 50 is installed on the roof of the residence, and the heating unit 50 is installed on the roof of the residence, and the tank unit 60 including the hot water storage tank 10 is installed in the basement. The inflow pipe 21 and the outflow pipe 27 of the hot water supply circuit 20 connecting the heating unit 50 and the hot water storage tank 10 have a length of more than a dozen meters, and from the hot water storage tank 10 in the basement toward the heating unit 50 on the roof, It is piped in the form of rising outside the house.

  Even when the heating unit 50 is installed on the ground outside the house, most of the inflow pipe 21 and the outflow pipe 27 connected to the hot water storage tank 10 installed in the basement or the like are routed around the attic. In many cases (referred to as torii piping), the inflow pipe 21 and the outflow pipe 27 once rise at a long distance from the hot water storage tank 10 and then descend toward the heating unit 50. In addition, the inflow pipe 21 and the outflow pipe 27 are normally insulated by a heat insulating material (not shown) for the purpose of reducing the heat radiation of hot water flowing through the inside and preventing freezing.

(5) Control device 70
Further, the heat pump hot water supply device 1 includes a hot water storage temperature sensor 16, an incoming water temperature sensor 28, a hot water temperature sensor 29, an outside air temperature sensor 55, a compressor 31, a blower 34, and a control device 70 to which the water pump 23 is connected. The control device 70 is disposed in the outer case 51 of the heating unit 50. The control device 70 includes a CPU (microcomputer) in which a program is stored. In the embodiment, the control device 70 is based on the temperatures detected by the hot water storage temperature sensor 16, the incoming water temperature sensor 28, the outgoing hot water temperature sensor 29, and the outside air temperature sensor 55. 31, the water pump 23, and the blower 34 are configured to be controlled. Further, the control device 70 has a timer function, and a remote control (operation panel) 71 for performing setting and other operations of the timer function and displaying an error is connected to the control device 70. Arranged in the outer case 51.

(6) Circulation of hot water in the hot water supply circuit 20 When the water pump 23 of the hot water supply circuit 20 is operated by the control device 70, the hot water in the hot water storage tank 10 is taken out from the lower part of the hot water storage tank 10, and the inflow pipe It rises in 21 toward the roof. Hot water supply water that has risen in the inflow pipe 21 and entered the heating unit 50 from the connection port 52 circulates in the water flow passage 42 of the water heat exchanger 40 via the water inlet pipe 22, the water pump 23, and the water outlet pipe 24. Then, it flows through the hot water outlet pipe 26 and reaches the outlet pipe 27 from the connection port 54. The hot water supply water flowing into the outflow pipe 27 descends in the outflow pipe 27 and flows into the upper part of the hot water storage tank 10.

(7) Refrigerant circulation in heat pump circuit 30 When the compressor 31 of the heat pump circuit 30 is operated by the control device 70, the high-temperature refrigerant (carbon dioxide) discharged from the compressor 31 is supplied to the water heat exchanger 40. The refrigerant flow passage 41 is circulated to exchange heat between the high-temperature refrigerant in the refrigerant flow passage 41 and the hot water supply water in the water flow passage 42. Thereby, the hot water for the hot water supply circuit 20 is heated by the water heat exchanger 40. On the other hand, the temperature of the high-temperature refrigerant is lowered by heating the hot water supply water with the water heat exchanger 40. The refrigerant further passes through the expansion valve 33 and expands to a low temperature and low pressure state to become a gas-liquid two-phase refrigerant. This gas-liquid two-phase refrigerant flows into the evaporator 32 and evaporates. Since the outside air is ventilated to the evaporator 32 by the blower 34, the refrigerant pumps up heat from the outside air by the endothermic action accompanying evaporation. The refrigerant that has absorbed heat in the evaporator 32 repeats circulation that is sucked into the compressor 31.

(8) Boiling operation Further, when hot water is used at the hot water supply destination, the hot water supply water in the upper part of the hot water storage tank 10 flows out into the hot water supply pipe 13, and the amount of the discharged water flows from the water supply pipe 11 to the lower part of the hot water storage tank 10. Water is supplied. That is, by using hot water, the hot water supply water in the hot water storage tank 10 is reduced, and the low temperature hot water supply water is increased from the lower part in the hot water storage tank 10, so that the temperature detected by the hot water temperature sensor 16 is gradually lowered. Will do.

  The control device 70 determines whether or not the temperature detected by the hot water storage temperature sensor 16 has dropped below the predetermined hot water storage temperature T1 in step S1 of the flowchart of FIG. 2, and the hot water in the hot water storage tank 10 is used as described above. When the temperature detected by the hot water storage temperature sensor 16 becomes equal to or lower than the hot water storage temperature T1, the control device 70 proceeds from step S1 to step S2, starts the operation of the compressor 31, the blower 34, and the water pump 23, and performs the boiling operation. Begin.

  Since the high-temperature refrigerant is circulated through the refrigerant flow passage 41 of the water heat exchanger 40, the hot water supply water circulated through the water flow passage 42 is heated and then flows into the hot water storage tank 10. Thereby, hot water is stored in the hot water storage tank 10. The controller 70 determines whether or not the temperature of the hot water supply water in the inlet pipe 22 detected by the incoming water temperature sensor 28 in step S3 is equal to or higher than a predetermined incoming water temperature T2 (T1 <T2), and is lower than the incoming water temperature T2. If so, continue boiling operation. Thereafter, when the detected temperature of the incoming water temperature sensor 28 becomes equal to or higher than the incoming water temperature T2, the control device 70 proceeds from step S3 to step S4, and stops the compressor 31 and the blower 34. The water pump 23 continues to operate.

  Next, the control device 70 proceeds to step S5, and the temperature of the hot water in the hot water outlet pipe 26 on the hot water side of the water heat exchanger 40 detected by the hot water temperature sensor 29 is detected by the incoming water temperature sensor 28. It is determined whether or not the temperature of the hot water supply water in the water inlet pipe 22 on the water inlet side 40 has become lower than 40. When the temperature detected by the hot water temperature sensor 29 is higher than the temperature detected by the incoming water temperature sensor 28, the operation of the water pump 23 is continued as it is, and the heat of the water heat exchanger 40 after the compressor 31 is stopped is recovered. To do.

  Thereafter, when the detected temperature of the hot water temperature sensor 29 becomes equal to or lower than the detected temperature of the incoming water temperature sensor 28, the control device 70 proceeds to step S6, stops the water pump 23, and ends the boiling operation. In this way, hot water of a predetermined high temperature is always stored in the hot water storage tank 10 during operation.

  Even when the temperature detected by the hot water storage temperature sensor 16 is not lower than the hot water storage temperature T1, the control device 70 is compressed even when the time measured by the timer function after the end of the previous boiling operation reaches a predetermined time. The machine 31, the blower 34, and the water pump 23 are operated, and the boiling operation is started. Thereafter, after the operations of step S3 to step S6 are executed in the same manner, the boiling operation is finished.

  In this way, the control device 70 performs a boiling operation for storing hot water supply water at a predetermined temperature in the hot water storage tank 10. The hot water storage temperature sensor 16 for detecting the temperature of the hot water supply water in the hot water storage tank 10 is stored in the hot water storage tank 10. It is provided at a predetermined position in the vertical direction of the tank 10, the hot water storage temperature sensor 16 is connected to the control device 70, and the control device 70 performs a boiling operation based on the detected temperature of the hot water storage temperature sensor 16. Therefore, it is not necessary to provide a control device on the hot water storage tank 10 side, and a general-purpose product can be used as the hot water storage tank 10, which is highly versatile.

(9) Freezing prevention operation (including backflow judgment)
Next, the freeze prevention operation (including the backflow determination) executed by the control device 70 will be described with reference to the flowchart of FIG. As described above, the inflow pipe 21 and the outflow pipe 27 that are mainly piped with a relatively long dimension outside the house are heat insulating materials (not shown) for the purpose of reducing the heat radiation of hot water flowing inside and preventing freezing. However, if the heat insulation is not sufficient, or if the outside air temperature becomes extremely low in winter, the hot water supply water in the inflow pipe 21 and the outflow pipe 27 of the hot water supply circuit 20 is frozen.

  Therefore, the control device 70 performs the freeze prevention operation for the inflow pipe 21 and the outflow pipe 27. That is, when the water pump 23 is stopped, the control device 70 detects the temperature of the hot water supply water on the water inlet side of the water heat exchanger 40 provided in the heating unit 50 and the water heat exchanger. The temperature of hot water supply water detected by the hot water temperature sensor 29 for detecting the temperature of hot water supply water 40 on the side of the hot water 40 is constantly monitored, and the detected temperature of the incoming water temperature sensor 28 or the hot water temperature sensor 29 is a predetermined value T3 in step S7 of FIG. It is determined whether or not the temperature has fallen below (a predetermined low temperature higher than the freezing point). As is apparent from the flowchart of FIG. 2 described above, when the water pump 23 is stopped, the compressor 31 is also stopped (the same applies hereinafter).

  If the detected temperatures of the incoming water temperature sensor 28 and the hot water temperature sensor 29 are higher than the predetermined value T3, the process proceeds to step S8, and the control device 70 determines whether or not a predetermined backflow determination condition is satisfied. The reverse flow determination condition will be described later. If it is assumed that the reverse flow determination condition is not satisfied at present, the control device 70 returns to another control.

  In the state where the water pump 23 is stopped, when the detected temperature of the incoming water temperature sensor 28 or the hot water temperature sensor 29 is lowered below the predetermined value T3 due to a decrease in the outside air temperature or the like, the control device 70 proceeds from step S7 to step S9. Then, the operation of the water pump 23 is started. By operating the water pump 23, hot water supply water in the lower part of the hot water storage tank 10 is taken out to the water inlet pipe 21, passed through the water inlet pipe 22 and the water outlet pipe 24 to the water flow passage 42 of the water heat exchanger 40, and then the hot water outlet pipe. 26, the hot water supply circuit 20 is circulated so as to return to the upper part of the hot water storage tank 10 through the outflow pipe 27.

  Next, the control device 70 determines whether or not the predetermined time t1 has elapsed in step S10, and continues that state if it has not elapsed. After continuing the operation of the water pump 23 for a predetermined time t1, the control device 70 proceeds from step S10 to step S11, and next determines whether or not the detected temperature of the incoming water temperature sensor 28 is lower than the predetermined incoming water temperature T2. . When the detected temperature of the incoming water temperature sensor 28 is equal to or higher than the incoming water temperature T2 in step S11, the control device 70 proceeds to step S18 and stops the water pump 23.

  On the other hand, when the detected temperature of the incoming water temperature sensor 28 is lower than the incoming water temperature T2 in step S11, the control device 70 proceeds to step S12 and determines whether or not a predetermined time t2 has elapsed. When the detected temperature of the incoming water temperature sensor 28 is lower than the incoming water temperature T2 in step S11 for a predetermined time t2 in step S12, the control device 70 proceeds to step S13 and starts operation of the compressor 31 and the blower 34. (The water pump 23 continues to operate). That is, if the detected temperature of the incoming water temperature sensor 28 does not become equal to or higher than the incoming water temperature T2 even if the water pump 23 is operated for a predetermined time t1 + t2, the controller 70 starts the above-described boiling operation.

  Next, the control device 70 determines whether or not the temperature of the hot water supply water in the inlet pipe 22 detected by the incoming water temperature sensor 28 in step S14 is equal to or higher than the incoming water temperature T2, and if it is lower than the incoming water temperature T2, the boiling operation is performed. Continue. Thereafter, when the detected temperature of the incoming water temperature sensor 28 becomes equal to or higher than the incoming water temperature T2, the control device 70 proceeds from step S14 to step S15 and stops the compressor 31 and the blower 34 (the water pump 23 continues to operate).

  Next, the control device 70 proceeds to step S16, and the temperature of the hot water in the hot water outlet pipe 26 on the hot water side of the water heat exchanger 40 detected by the hot water temperature sensor 29 is detected by the incoming water temperature sensor 28. It is determined whether or not the temperature of the hot water supply water in the water inlet pipe 22 on the water inlet side 40 has become lower than 40. When the detected temperature of the hot water temperature sensor 29 is higher than the detected temperature of the incoming water temperature sensor 28, the operation of the water pump 23 is continued as it is, and the water heat exchanger 40 after the compressor 31 is stopped as described above. Recover heat.

  Thereafter, when the detected temperature of the hot water temperature sensor 29 becomes equal to or lower than the detected temperature of the incoming water temperature sensor 28, the control device 70 proceeds to step S6, stops the water pump 23, and ends the freeze prevention operation. As described above, when the temperature detected by the incoming water temperature sensor 28 or the hot water temperature sensor 29 falls below the predetermined value T3, the hot water supply water is circulated in the hot water supply circuit 20, and when the temperature of the hot water supply water is low, the boiling operation is performed. Is also executed, so that the hot water supply water in the water inlet pipe 21 and the hot water outlet pipe 27 is prevented from freezing.

(10) Backflow determination Here, when the heating unit 50 is installed on the roof of the residence and the tank unit 60 is installed in the basement as in the embodiment, the heating unit 50 is more than the hot water storage tank 10 of the tank unit 60. When the temperature of the hot water supply in the outflow pipe 27 is lowered in the winter or the like when the water pump 23 is stopped because the water pump 23 is stopped, the hot water in the hot water storage tank 10 is caused by the difference in density as described above. The upper hot water supply water (hot water) flows back to the outflow pipe 27. The same applies to the torii piping described above.

  The hot water supply water having a high temperature flowing into the outflow pipe 27 eventually enters the heating unit 50 and reaches the water intake pipe 22 through the hot water discharge pipe 26, the water flow passage 42, the water discharge pipe 24, and the water pump 23. Accordingly, the detected temperatures of the hot water temperature sensor 29 and the incoming water temperature sensor 28 that detect the temperature of the hot water supply water in the hot water outlet pipe 26 and the incoming water pipe 22 do not become the predetermined value T3 or less.

  Therefore, in step S7 in the flowchart of FIG. 3, the process goes to step S9, and the freeze prevention operation is not executed. However, since the temperature does not increase up to the inflow pipe 21, if the outside air temperature decreases in winter or the like, the hot water supply water in the inflow pipe 21 will eventually freeze. Therefore, in the embodiment, whether or not the reverse flow phenomenon occurs in step S8 even when the detected temperatures of the incoming water temperature sensor 28 and the hot water temperature sensor 29 do not become the predetermined value T3 or less in step S7 of the flowchart of FIG. Judgment is made.

(10-1) Backflow determination condition The backflow phenomenon can be detected by a temperature change of hot water in the heating unit 50. That is, when the previous boiling operation and freeze prevention operation are completed (the compressor 31 is stopped and the water pump 23 is also stopped), the detected temperatures of the incoming water temperature sensor 28 and the hot water temperature sensor 29 are lowered. However, if hot water for hot water flows back into the outflow pipe 27 while the water pump 23 is stopped, the temperatures detected by the incoming water temperature sensor 28 and the outgoing hot water temperature sensor 29 will start to rise.

Therefore, the backflow determination condition in this embodiment is as follows. That is,
(I) The water pump 23 is stopped.
(Ii) The temperature detected by the incoming water temperature sensor 28 or the hot water temperature sensor 29 has increased by a predetermined value or more.
The condition (ii) may be that the temperature detected by the incoming water temperature sensor 28 or the hot water temperature sensor 29 once decreases and then increases and rises by a predetermined value or more.

(10-2) Operation when the reverse flow determination condition is satisfied When the detected temperature of the incoming water temperature sensor 28 or the hot water temperature sensor 29 is higher than the predetermined value T3 in step S7 of the flowchart of FIG. When the reverse flow determination conditions (i) and (ii) are determined and all of the conditions (i) and (ii) are satisfied, it is determined that the hot water supply water is flowing back into the outflow pipe 27, and step S8 is performed. From step S9, the operation of the water pump 23 is started. The following steps S10 to S18 are executed to execute the above-described freeze prevention operation, and the water pump 23 circulates hot water supply water in the hot water supply circuit 20 and operates for a predetermined time (t1 + t2). When it is low, the compressor 31 is also operated to heat the hot water supply water in the same manner as the boiling operation.

  Thus, the control device 70 detects the temperature of the hot water supply water of the hot water supply circuit 20 located in the heating unit 50, in the embodiment, the temperature of the hot water supply water 28 on the incoming water side of the water heat exchanger 40, or When the detected temperature of the hot water supply temperature sensor 29 for detecting the temperature of hot water supply water on the hot water side of the water heat exchanger 40 falls below a predetermined value T3, an antifreezing operation for operating the water pump 23 is performed and the water pump 23 When the temperature of the hot water supply water of the hot water supply circuit 20 located in the heating unit 50, in the embodiment, the detected temperature of the incoming water temperature sensor 28 or the outgoing hot water temperature sensor 29 rises, the water pump 23 is operated. Therefore, when a reverse flow phenomenon of hot hot water supply water (hot water) from the hot water storage tank 10 occurs in the hot water supply circuit 20, the water pump 23 is operated to circulate hot water supply water in the hot water supply circuit 20. It is possible to.

  Thereby, when the heating unit 50 is disposed at a position higher than the tank unit 60 as in the embodiment, or a part of the inflow pipe 21 and the outflow pipe 27 of the hot water supply circuit 20 is disposed at a position higher than the tank unit 60. The anti-freezing operation is not executed due to the reverse flow phenomenon that is likely to occur when the torii piping is installed, and the inconvenience that the hot water in the inflow pipe 21 of the hot water supply circuit 20 is frozen can be avoided. Further, since there is no need to provide a check valve or the like on the outflow pipe 27 of the hot water supply circuit 20, it is possible to prevent an increase in cost due to an increase in the number of parts.

  As described above, the temperature of the hot water supply water of the hot water supply circuit 20 located in the heating unit 50 (the detected temperature of the incoming water temperature sensor 28 or the outgoing hot water temperature sensor 29) is determined by the control device 70 in a state where the water pump 23 is stopped. In the case where the water pump 23 is operated when the water pump 23 is once increased and then turned up, it is possible to accurately determine the occurrence of the backflow phenomenon that occurs after the water pump 23 is stopped.

  Further, as in the embodiment, even when the control device 70 operates the water pump 23 for a predetermined time (t1 + t2) in the freeze prevention operation, the temperature of the hot water on the incoming side of the water heat exchanger 40 (the detected temperature of the incoming temperature sensor 28). Is a predetermined low value (a value lower than the incoming water temperature T2), it is possible to more smoothly realize prevention of freezing of the hot water supply circuit 20 by operating the compressor 31, but the control device 70 In the state where the water pump 23 is stopped, the temperature of the hot water supply water in the hot water supply circuit 20 located in the heating unit 50 (in the embodiment, the detected temperature of the incoming water temperature sensor 28 or the outgoing hot water temperature sensor 29) also increases. In the embodiment, since the anti-freezing operation is executed, the freezing of the inflow pipe 21 of the hot water supply circuit 20 when the backflow phenomenon occurs can be more reliably prevented.

(10-3) Backflow determination condition 2
Here, the reverse flow determination conditions are not limited to those described above, and may be as follows. That is,
(I) The water pump 23 is stopped.
(Ii) The temperature detected by the incoming water temperature sensor 28 or the hot water temperature sensor 29 has risen by a predetermined value or more within a predetermined time.
The condition (ii) may be that the temperature detected by the incoming water temperature sensor 28 or the hot water temperature sensor 29 once decreases, then starts increasing, and increases within a predetermined time by a predetermined value or more.
If the control device 70 proceeds to step S9 when all of the above conditions (i) and (ii) are satisfied, the influence of the disturbance is eliminated and the occurrence of the backflow phenomenon is more accurately determined. Will be able to.

(10-4) Backflow determination condition 3
Further, the reverse flow determination condition may be as follows. That is,
(I) The water pump 23 is stopped.
(Ii) The detected temperature of the incoming water temperature sensor 28 or the outgoing hot water temperature sensor 29 has risen by a predetermined value or more (condition (ii) is that the detected temperature of the incoming water temperature sensor 28 or the outgoing hot water temperature sensor 29 decreases once and then increases) It may be that it has turned over a predetermined value.)
(Iii) The outside air temperature detected by the outside air temperature sensor 55 is below a predetermined value (a predetermined value lower than the predetermined value T3 and above the freezing point, such as 2 ° C.).
If the control device 70 proceeds to step S9 when all of the above conditions (i) to (iii) are satisfied, the backflow phenomenon in the low outside air temperature environment is accurately detected, and is unnecessary. The operation of the water pump 23 can be avoided.

(10-5) Backflow determination condition 4
Further, the reverse flow determination condition may be as follows. That is,
(I) The water pump 23 is stopped.
(Ii) The detected temperature of the incoming water temperature sensor 28 or the outgoing hot water temperature sensor 29 has increased by a predetermined value or more within a predetermined time (the condition (ii) is that the detected temperature of the incoming water temperature sensor 28 or the outgoing hot water temperature sensor 29 is temporarily lowered). After that, it may turn up and rise by a predetermined value or more within a predetermined time).
(Iii) The outside air temperature detected by the outside air temperature sensor 55 is below a predetermined value (a predetermined value lower than the predetermined value T3 and above the freezing point, such as 2 ° C.).
Then, even when the control device 70 proceeds to step S9 when all of the above conditions (i) to (iii) are satisfied, the reverse flow phenomenon in the low outside air temperature environment is accurately detected, and unnecessary water is used. The operation of the pump 23 can be avoided.

  Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be further modified based on the technical idea of the present invention. Not too long.

DESCRIPTION OF SYMBOLS 1 Heat pump type hot water supply apparatus 10 Hot water storage tank 16 Hot water storage temperature sensor 20 Hot water supply circuit 21 Inflow pipe 22 Inlet pipe 23 Water pump 24 Outlet pipe 26 Outlet pipe 27 Outflow pipe 28 Incoming temperature sensor 29 Outlet temperature sensor 30 Heat pump circuit 31 Compressor 32 Evaporator 33 Expansion Valve 34 Blower 40 Water Heat Exchanger 41 Refrigerant Flow Path 42 Water Flow Path 50 Heating Unit 55 Outside Air Temperature Sensor 60 Tank Unit 70 Control Device

Claims (9)

A heating unit provided with a heat pump circuit formed by connecting a compressor, a water heat exchanger, a decompressor, and an evaporator;
A tank unit provided with a hot water storage tank for storing hot water supply water;
A hot water supply circuit that takes out hot water in the hot water storage tank from the lower part of the hot water storage tank by a water pump, flows to the water heat exchanger, and then flows into the upper part of the hot water storage tank;
In a heat pump type hot water supply apparatus comprising: a control device that performs a boiling operation for heating hot water flowing through the water heat exchanger with a refrigerant by operating the water pump and the compressor;
When the temperature of the hot water supply water in the hot water supply circuit located in the heating unit has dropped below a predetermined value, the control device performs an anti-freezing operation for operating the water pump,
A heat pump type hot water supply apparatus that operates the water pump when the temperature of the hot water supply water in the hot water supply circuit located in the heating unit rises while the water pump is stopped.   The controller, when the water pump is stopped, operates the water pump when the temperature of the hot water supply water in the hot water supply circuit located in the heating unit once decreases and then starts to increase. The heat pump type hot water supply apparatus according to claim 1.   The control device operates the water pump when the temperature of the hot water supply water of the hot water supply circuit located in the heating unit rises by a predetermined value or more within a predetermined time while the water pump is stopped. The heat pump type hot water supply apparatus according to claim 1 or 2, wherein the heat pump type hot water supply apparatus is provided.   When the temperature of hot water in the hot water supply circuit located in the heating unit rises while the outside air temperature is equal to or lower than a predetermined value and the water pump is stopped, the control device The heat pump type hot water supply apparatus according to any one of claims 1 to 3, wherein the heat pump type hot water supply apparatus is operated.   In the freeze prevention operation, the control device operates the compressor if the temperature of the hot water supply water on the water inlet side of the water heat exchanger is a predetermined low value even if the water pump is operated for a predetermined time. The heat pump type hot water supply apparatus according to any one of claims 1 to 4, wherein the heat pump type hot water supply apparatus is provided.   The said control apparatus performs the said freeze prevention operation, when the temperature of the hot water supply water of the said hot water supply circuit located in the said heating unit rises in the state which the said water pump has stopped. 5. A heat pump type hot water supply apparatus according to 5.   The temperature of the hot water supply water in the hot water supply circuit located in the heating unit is the temperature of the hot water supply water on the inlet side of the water heat exchanger or the temperature of hot water supply water on the outlet side of the water heat exchanger. The heat pump type hot water supply apparatus according to any one of claims 1 to 6.   The heat pump type hot water supply apparatus according to any one of claims 1 to 7, wherein the heating unit is disposed at a position higher than the tank unit. The hot water supply circuit is located between the heating unit and the tank unit, an inflow pipe for taking out hot water in the hot water storage tank from the lower part of the hot water storage tank, and hot water after having passed through the water heat exchanger An outlet pipe for allowing water to flow into the upper part of the hot water storage tank;
The heat pump hot water supply apparatus according to any one of claims 1 to 8, wherein at least a part of the inflow pipe and the outflow pipe is disposed at a position higher than the tank unit. .

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