JP2007333340A - Heat pump type hot water supply apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve defrosting capacity in a cold district, regarding a heat pump type hot water supply apparatus having the function of defrosting operation for eliminating frost formed on an evaporator during winter. <P>SOLUTION: The heat pump type hot water supply apparatus comprises a refrigerating circuit having a compressor, a refrigerant-water heat exchanger, a pressure reducer and an evaporator, and a hot water storage tank circulating water heated by the refrigerant-water heat exchanger of the refrigerating circuit, in a storable manner. The heat pump type hot water supply apparatus also comprises a heat pump going tube 10 connecting the lower part of the hot water storage tank 2 to the refrigerant-water heat exchanger, and a heat pump return tube 13 connecting the refrigerant-water heat exchanger to the upper part of the hot water storage tank 2. The hot water storage tank, the heat pump going tube, the refrigerant-water heat exchanger and the heat pump return tube are allowed to communicate to form a heat pump circulating circuit 14, and the heat pump going tube and the heat pump return tube are connected by a defrosting by-pass tube 25 to form a defrosting by-pass circuit 27. The defrosting by-pass circuit 27 is provided with an auxiliary tank 26. The defrosting by-pass circuit 27 is also provided with a switching means 24 switching the heat pump circulating pump 11, the heat pump circulating circuit and the defrosting by-pass circuit 27. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat pump hot water supply apparatus having a function of a defrosting operation for removing frost adhering to an evaporator during a winter period.

Conventionally, this type includes, for example, a compressor that compresses refrigerant, a refrigerant-to-water heat exchanger that performs heat exchange between the refrigerant discharged from the compressor and flowing hot water, and the refrigerant-to-water heat exchange. A water heater that heats hot water running water in a heat pump cycle that combines an expansion valve that depressurizes the refrigerant flowing out of the heater and an evaporator that evaporates the refrigerant flowing out of the expansion valve and absorbs heat into the refrigerant, A drain pan that receives and drains water droplets generated during defrosting operation due to condensation of water in the air in the evaporator, and a hot water supply that flows into the refrigerant-to-water heat exchanger that water droplets freeze and grow in the drain pan By arranging a mechanism that prevents part of the running water piping from being used in the drain pan, it is possible to prevent water droplets from freezing and growing on the drain pan during defrosting operation of the heat pump cycle under temperature conditions at low outside temperatures. For hot water supply Part of the water pipe is prevented by arranging the drain pan. (For example, see Patent Document 1)
JP 2004-218861 A

  However, this conventional product does not worry about freezing of the drain pan, but when it is used in a cold area, depending on the use condition of the hot water supply device, it may be affected by adverse conditions such as low outside air temperature or snowfall. In the normal defrosting operation, the frost of the evaporator remains without melting, and the amount of frost remaining in the long-time operation further increases and eventually the heat exchange by the evaporator becomes impossible, causing an abnormal stop. was there.

  In claim 1, a refrigeration circuit having a compressor, a refrigerant-to-water heat exchanger, a decompressor, and an evaporator, and a hot water storage tank that circulates water heated by the refrigerant-to-water heat exchanger of the refrigeration circuit in a storable manner. A heat pump return pipe connecting the refrigerant-to-water heat exchanger and the upper part of the hot water storage tank, and a heat pump return pipe connecting the refrigerant-to-water heat exchanger and the upper part of the hot water storage tank. A hot water storage tank, a heat pump forward pipe, a refrigerant-to-water heat exchanger, and a heat pump return pipe are connected to form a heat pump circulation circuit, and the heat pump forward pipe and the heat pump return pipe are connected by a defrost bypass pipe. A defrosting bypass circuit is provided, an auxiliary tank is provided in the defrosting bypass circuit, and switching means for switching the heat pump circulation pump, the heat pump circulation circuit, and the defrost bypass circuit to the defrost bypass circuit is provided. Those digits.

  According to a second aspect of the present invention, an evaporation temperature sensor is provided in the evaporator or a refrigerant pipe on the evaporator inlet side, a water inlet sensor is provided in the inlet side pipe of the refrigerant-to-water heat exchanger, and the evaporation temperature sensor is a predetermined filter. When the frost condition is satisfied, the switching means is operated to operate the refrigeration circuit in a state where the defrost bypass circuit is communicated, hot water is stored in the auxiliary tank, and the switching means when the water sensor reaches a predetermined temperature. And a controller for defrosting the evaporator with hot water stored in the auxiliary tank.

  According to a third aspect of the present invention, when the water inlet sensor reaches a predetermined temperature, the depressurizer is opened to start the defrosting operation, and the switching means is switched to remove the evaporator even with hot water stored in the auxiliary tank. A control unit that performs frost is provided.

  According to the present invention, the defrosting capability can be greatly improved, and even when adverse conditions such as low outside air temperature and snowfall overlap when used in a cold region, a smooth defrosting operation can be performed. It is possible to prevent an abnormal stop caused by frost.

  Hereinafter, preferred examples for carrying out the present invention will be described.

Next, Example 1 of the present invention will be described with reference to FIGS.
Reference numeral 1 denotes a hot water storage tank unit for storing a hot water storage tank 2 and the like for storing hot water. Reference numeral 3 denotes a heat pump unit as a heating means for heating the hot water in the hot water storage tank 2. It is composed of a heat exchanger 5, an electronic expansion valve 6 as a decompressor, and a forced air-cooled evaporator 7. This heat pump unit 3 uses carbon dioxide as a refrigerant to constitute a supercritical refrigeration circuit. It is. Further, a heat pump control unit 8 for driving and controlling the refrigeration circuit by the compressor 4 and the electronic expansion valve 6 is provided.

  The heat pump unit 3 includes a grid-like air inlet on the back and left side, and an air outlet having a substantially circular grid-like guard on the front, and a fin-tube heat exchanger inside the inlet. The evaporator 7 is provided with a blower fan 9 inside the blower outlet, and the suction port, the evaporator 7, the blower fan 11, and the blower outlet are communicated to form a blower path.

  A heat pump forward pipe 10 connects a lower part of the hot water storage tank 2 and the refrigerant-to-water heat exchanger 5. A heat pump circulation pump 11 is attached to the first three-way valve between the heat pump circulation pump 11 and the hot water storage tank 2. 12 is provided. A heat pump return pipe 13 connects the refrigerant-to-water heat exchanger 5 and the upper part of the hot water storage tank 2, and connects the hot water storage tank 2, the heat pump forward pipe 10, the refrigerant-to-water heat exchanger 5, and the heat pump return pipe 13. A heat-pump circuit 14 is formed.

  A water inlet 15 is connected to the lower part of the hot water storage tank 2 and supplies water to the hot water storage tank 2. A hot water pipe 16 is connected to the upper part of the hot water storage tank 2 and discharges hot water stored in the hot water. 17 is an intermediate hot water pipe connected to an intermediate position of the hot water storage tank 2. 18 is an intermediate mixing valve for mixing hot water from the outlet hot water pipe 16 and hot water from the intermediate hot water outlet pipe 17 so as to reach an arbitrary temperature. Reference numeral 19 denotes a water supply pipe branched from the water intake pipe 15. A hot water supply mixing valve 20 mixes hot water from the intermediate mixing valve 18 and water supply from the water supply pipe 19 at a hot water supply set temperature.

  A heating bypass pipe 21 is connected to the heat pump circulation circuit 14 so as to be bypassed via the first three-way valve 12. A heating heat exchanger 22 is provided in the middle of the heating bypass pipe 21 and has a heat radiating portion (not shown) connected to the secondary side thereof. Reference numeral 23 denotes an intermediate return pipe connected to an intermediate position of the hot water storage tank 2 on the downstream side of the heating heat exchanger 22 in the middle of the heating bypass pipe 21. The first three-way valve 12 is composed of an electric three-way valve that switches whether the heat pump unit 3 side of the heat pump forward pipe 10 is connected to the hot water storage tank 2 side or the heating bypass pipe 21 side of the heat pump forward pipe 10. . The first three-way valve 12 may be provided on the heaton return pipe 13 side of the heaton circulation circuit 24.

  Reference numeral 24 denotes a second three-way valve as a switching means provided in the heat pump return pipe 13 on the heat pump unit 3 side than the heating bypass pipe 21, and a defrosting bypass pipe 25 is provided from the second three-way valve 24 to the heat pump forward pipe 10. ing. An auxiliary tank 26 is provided between the defrosting bypass pipe 25 of the heat pump forward pipe 10 and the heat pump circulation pump 11 and stores about 5 liters of hot water therein. The auxiliary tank 26 of the heat pump forward pipe 10, the heat pump circulation pump 11 and the refrigerant A defrost bypass circuit 27 is formed by communicating the anti-water heat exchanger 5 and the defrost bypass pipe 25.

  28 is a water inlet sensor attached near the inlet pipe of the refrigerant-to-water heat exchanger 5 or the refrigerant-to-water heat exchanger 5 inlet of the heat-pump forward pipe 10, and detects the temperature of the pipe by a thermistor sensor or the like. Reference numeral 29 denotes an outlet pipe of the refrigerant-to-water heat exchanger 5 or a boiling sensor attached in the vicinity of the refrigerant-to-water heat exchanger 5 inlet of the heat-pump return pipe 13. The temperature of this is detected. Reference numeral 30 denotes an evaporation temperature sensor attached to the evaporator 7 or a refrigerant pipe near the inlet of the evaporator 7, and detects the temperature of the refrigerant pipe by a thermistor sensor or the like.

  Reference numeral 31 denotes a control unit that mainly controls a microcomputer programmed in advance and controls the driving of the three-way valves 12 and 24, the circulation pump 14, the blower fan 11, and the like, and issues a command to the heat pump control unit 8. is there.

Here, a hot water storage operation for storing hot water heated by the heat pump unit 3 in the hot water storage tank 2 will be described.
At midnight, the control unit 31 starts the hot water storage operation so that the electric power unit price is cheap and rises up to a predetermined time in the morning, and the heat pump unit 3 and the hot water tank 2 communicate with each other. The heat pump circulation pump 11 and the heat pump unit 3 are driven and activated, and the hot water taken out from the lower part of the hot water storage tank 2 is heated to the boiling temperature by the heat pump unit 3 and stacked on the upper part of the hot water storage tank 2. Store hot water. When the desired amount of heat is stored, the heat pump circulation pump 11 and the heat pump unit 3 are stopped and the hot water storage operation is terminated.

Next, a hot water supply operation when the user opens the hot water tap to supply hot water will be described.
When the hot water tap is opened, hot water is stored in the hot water storage tank 2 from the water inlet pipe 15 and hot water is discharged from the hot water outlet pipe 16 at the same time. At this time, the hot water storage hot water is also discharged from the intermediate hot water discharge pipe 17 according to the mixing ratio of the intermediate mixing valve 18 and is mixed to a certain temperature by the intermediate mixing valve 18. Then, the hot water from the intermediate mixing valve 18 flows into the hot water supply mixing valve 20, is mixed with the water supply from the water supply pipe 19, and is supplied from the hot water tap at a desired hot water supply set temperature.

Next, the heating operation will be described.
When the heating request is generated, the control unit 31 starts the operation on the secondary side of the heating, and the first three-way valve 12 communicates with the heating bypass pipe 21 and the heat pump unit 3 side of the heat pump circulation circuit 14. Switching, driving and starting the heat pump circulation pump 11 and the heat pump unit 3, supplying the hot water boiled by the heat pump unit 3 directly to the heating heat exchanger 22, and exchanging heat with the secondary side to reduce the temperature Is directly circulated through the heat pump unit 3 and heated again by heating.

Next, the combined operation in which the heating operation and the hot water supply operation are performed simultaneously will be described.
When a request for hot water supply operation occurs during the heating operation, the control unit 31 switches the first three-way valve 12 so that the hot water storage tank 2 and the heat pump unit 3 communicate with each other. The hot water heated by the heat pump unit 3 passes through the heating heat exchanger 22, and the hot water whose temperature has decreased due to heat exchange with the secondary side is returned to the intermediate portion of the hot water storage tank 2 through the intermediate return pipe 23. The hot water stored in the lower part of the hot water storage tank 2 and the cold water flowing into the lower part of the hot water storage tank 2 from the inlet pipe 15 are circulated to the heat pump unit 3 through the heat pump forward pipe 10 and heated. On the other hand, the hot water returned to the intermediate part of the hot water storage tank 2 is discharged in an amount corresponding to the mixing ratio of the intermediate mixing valve 18 controlled by the control unit 31 through the intermediate hot water pipe 17, and hot water is supplied by the hot water mixing valve 20. Hot water is supplied as a set temperature hot water.

Next, the defrosting operation during the hot water storage operation will be described with reference to FIG.
During the winter period in the cold region, the control unit 31 starts the hot water storage operation so that it boils up to a predetermined time in the morning at midnight. If the evaporating temperature sensor 30 continues at −15 ° C. or lower, the controller 31 determines that the defrosting condition is satisfied, a lot of frost is generated in the evaporator 7 and the defrosting is necessary, and the second three-way valve 24 is removed. If switched to the frost bypass circuit 27 side, the hot water heated by the refrigerant-to-water heat exchanger 5 and circulating through the defrost bypass circuit 27 gradually rises and is stored in the auxiliary tank 26. When the temperature of the water inlet sensor 28 reaches 60 ° C., it is determined that a sufficient amount of heat for defrosting has been stored, and the expansion valve 6 is opened and hot refrigerant is sent to the evaporator 7 to remove frost adhering to the evaporator 7. The defrosting operation for melting is performed until the evaporation temperature sensor 30 reaches about 10 ° C. (maximum 15 minutes). Then, the second three-way valve 24 is switched to the heat-pump circuit 14 side, the expansion valve 6 is closed to a normal opening degree, the hot water storage operation is resumed, and the hot water storage operation is continued. When the desired amount of heat is stored, the heat pump circulation pump 11 and the heat pump unit 3 are stopped and the hot water storage operation is terminated.

  Thus, by providing the auxiliary tank 26 and the defrosting bypass circuit 27, the defrosting capability can be greatly improved, and smooth use is possible even when adverse conditions such as low outside air temperature and snowfall overlap when used in cold regions. It is possible to perform a defrosting operation and prevent an abnormal stop caused by the frost of the evaporator.

The schematic block diagram of one Example of this invention. The operation sequence diagram.

Explanation of symbols

2 Hot water storage tank 6 Expansion valve (pressure reducer)
7 Evaporator 10 Heaton Outlet Pipe 11 Heaton Circulation Pump 12 First Three-way Valve 13 Heaton Return Pipe 24 Second Three-way Valve 25 Defrost Bypass Pipe 26 Auxiliary Tank 27 Defrost Bypass Circuit 28 Incoming Sensor 30 Evaporation Temperature Sensor 31 Control Unit

Claims (3)

  A heat pump type equipped with a refrigeration circuit having a compressor, a refrigerant-to-water heat exchanger, a decompressor, and an evaporator, and a hot water storage tank that circulates water heated by the refrigerant-to-water heat exchanger of the refrigeration circuit so as to be storable. In the hot water supply apparatus, a heat pump forward pipe connecting the lower part of the hot water storage tank and the refrigerant to water heat exchanger, and a heat pump return pipe connecting the refrigerant to water heat exchanger and the upper part of the hot water storage tank, A hot water storage tank, a heat pump return pipe, a refrigerant-to-water heat exchanger, and a heat pump return pipe are connected to form a heat pump circulation circuit, and the heat pump return pipe and the heat pump return pipe are connected by a defrost bypass pipe for defrosting. A bypass circuit is formed, an auxiliary tank is provided in the defrost bypass circuit, and switching means for switching the heat pump circulation pump, the heat pump circulation circuit, and the defrost bypass circuit is provided in the defrost bypass circuit. Heat pump hot water supply apparatus according to.   When an evaporation temperature sensor is provided in the evaporator or the refrigerant pipe on the evaporator inlet side, a water inlet sensor is provided in the inlet pipe of the refrigerant to water heat exchanger, and the evaporation temperature sensor satisfies a predetermined defrosting condition. The refrigeration circuit is operated in a state where the switching means is operated and the defrost bypass circuit is in communication, hot water is stored in the auxiliary tank, and when the water sensor reaches a predetermined temperature, the switching means is switched and stored in the auxiliary tank. The heat pump type hot water supply apparatus according to claim 1, further comprising a controller that performs defrosting of the evaporator with the generated hot water.   When the water inlet sensor reaches a predetermined temperature, the depressurizer is opened to start a defrosting operation, and a control unit is provided for switching the switching means to defrost the evaporator even with hot water stored in an auxiliary tank. The heat pump type hot water supply apparatus according to claim 1 or 2, wherein

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