JP2008057857A - Heat pump water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat pump water heater compact and free from a shortage of hot water. <P>SOLUTION: The heat pump water heater comprises a refrigerant circuit 6 formed by annularly connecting a compressor 1, refrigerant side piping 2a of a hot water supply heat exchanger 2, an expansion valve 3 and an evaporator 4; a hot water storage circuit 14 formed by annularly connecting a hot water storage tank 7, a water circulating pump 8 and water side piping 2b of the hot water supply heat exchanger 2; and a hot water supply circuit 20 for supplying hot water of predetermined temperature by mixing hot water in the hot water storage tank 7 and water in water supply piping 17. An outlet side opening 10a of first hot water supply piping 10 for returning hot water heated in the water side piping 2b, to the upper part of the hot water storage tank 7, and an inlet side opening 15a of first hot water supply piping 15 for taking out hot water from the upper part of the hot water storage tank 7, are arranged to almost face each other. Even when the temperature of hot water discharged from the outlet side opening 10a is low, since the hot water is supplied flowing directly into the inlet side opening 15a, the temperature of hot water in the hot water storage tank 7 is not lowered to attain boiling-up operation of large capacity and high efficiency. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat pump water heater that uses hot water boiled with high efficiency by a heat pump for hot water supply.

  Conventionally, as a heat pump water heater that uses hot water boiled with high efficiency by a heat pump for hot water supply, as shown in FIG. 3, it has a direct hot water supply function that directly supplies boiled hot water without going through the hot water storage tank. (For example, refer to Patent Document 1).

  As shown in FIG. 3, the conventional heat pump water heater includes a compressor 101, a condenser 103, a decompression device 104, an evaporator 105, and an accumulator 106 that are sequentially connected in an annular shape to constitute a heat pump circuit 109. Reference numeral 108 denotes a blower that sends air to the evaporator 105.

  Further, the heat pump circuit 109 includes a defrosting unit that bypasses the refrigerant discharged from the compressor 101 to the evaporator 105 via the bypass valve 107. Further, in order to increase the capacity of the heat pump unit, the compressor 101a, Another heat pump cycle 109a including a condenser 103a, a decompression device 104a, an evaporator 105a, and an accumulator 106a is provided. Reference numeral 108a denotes a blower that sends air to the evaporator 105a. The heat pump cycle 109a includes defrosting means for bypassing the refrigerant discharged from the compressor 101a to the evaporator 105a via the bypass valve 107a.

  Further, the water supplied into the hot water supply tank 111 via the water supply pipe 113 and the pressure reducing valve 114 is carried from the bottom of the hot water supply tank 111 to the water heat exchanger 110 via the circulation pump 112, where the heat pump circuit 109, The heat exchange with 109a heats itself to become hot water and returns to the hot water supply tank 111. Hot water can be stored in the hot water supply tank 111 by this hot water storage circuit. When hot water is stored in the hot water supply tank 111, it is normal to set the boiling temperature at the heat pump high (about 75 ° C. to 90 ° C.) in order to secure the heat storage amount of the hot water supply tank 111.

  In addition, the water directly introduced from the water supply pipe 113 to the water heat exchanger 110 is heated by heat exchange with the heat pump circuits 109 and 109a, and the terminal 118 and the bathtub such as a shower and currant are used without passing through the hot water tank 111. A direct hot water supply path for supplying hot water to 119 is provided. In the middle of this direct hot water supply path, the mixing valve 120 for mixing the hot water at the outlet of the water heat exchanger 110 and the hot water in the hot water supply tank 111, and the mixing of the hot water mixed by the mixing valve 120 and the water in the water supply pipe 113 are mixed. A valve 121 and a flow rate adjustment valve 122 for adjusting the hot water supply flow rate at the outlet of the mixing valve 121 are provided, and hot water having a predetermined temperature can be supplied from the use terminal 118 or the bathtub 119. Reference numeral 116 denotes a bathtub circulation pump when the water and hot water in the bathtub 119 are additionally cooked.

The heat pump has the characteristics that the lower the boiling temperature is, the higher the operation efficiency (COP) is, and the operation with a large capacity is possible, so when supplying hot water without going through the hot water supply tank 111, The boiling temperature is set lower than that during the hot water storage circuit operation (about 42 ° C. to 65 ° C.). As a result, not only can the energy saving be achieved by the direct hot water supply function of the heat pump circuits 109 and 109a, but the provision of the hot water supply tank 111 can compensate for the lack of heating capacity at the start of operation of the heat pump circuits 109 and 109a. Responsiveness to the load is improved. Furthermore, by storing the heat pump circuits 109 and 109a and the water circulation circuit 117 including the hot water supply tank 111 or the like in one outer box 123, compared to the conventional electric water heater in which the heat pump unit and the tank unit are separated. The main body can be made compact, and workability is improved.
JP 2003-279133 A

  However, in the configuration of the conventional heat pump water heater, there is a problem that a dedicated water circuit is required when performing a direct hot water supply operation, which increases costs. In heat pump water heaters that do not have a direct hot water supply function, the operation efficiency of the heat pump is improved by operating at a lower boiling temperature, but the heated water (42 ° C to 65 ° C) is stored in the hot water storage tank. There was a problem that the temperature in the hot water storage tank was lowered by mixing with hot hot water (about 75 ° C. to 90 ° C.), and the amount of heat stored in the hot water storage tank was reduced. For example, when 85 ° C hot water is stored in the upper part of the tank and the large capacity operation of the heat pump circuit (boiling temperature 42 ° C) is performed, 85 ° C hot water and 42 ° C hot water are mixed in the upper part of the tank. Thus, the heat storage temperature in the upper part of the tank is lowered to about 60 ° C to 65 ° C. Further heating of hot water at 60 ° C. with a heat pump is usually not performed because of a reduction in operating efficiency. Therefore, in the case of the above example, when the hot water temperature at the upper part of the tank is lowered from 85 ° C. to 60 ° C., the heat storage amount corresponding to about 25 K (= 85 ° C.-65 ° C.) is lowered.

  The present invention solves the above-described conventional problems, and a heat pump water heater capable of high-capacity and high-efficiency boiling operation without reducing the amount of heat stored in the tank without having a dedicated direct hot water supply circuit. The purpose is to provide.

  In order to solve the above conventional problems, a heat pump water heater of the present invention includes a refrigerant circuit formed by annularly connecting a refrigerant side pipe, an expansion valve, and an evaporator of a compressor, a hot water supply heat exchanger, and a hot water storage tank. A hot water storage circuit formed by annularly connecting a water circulation pump and a water side pipe of the hot water heat exchanger, and hot water in the hot water storage tank and water in the water supply pipe are mixed to supply hot water at a predetermined temperature. In a heat pump water heater having a hot water supply circuit, an outlet side opening of a first hot water storage pipe for returning the hot water heated by the water side pipe to the upper part of the hot water storage tank, and a first for taking out the hot water from the upper part of the hot water storage tank. It is arranged so as to be substantially opposite to the inlet side opening of the hot water supply pipe. Even if the temperature of the hot water discharged from the outlet side opening of the first hot water storage pipe is low, it is directly open to the inlet side of the first hot water supply pipe. Since it flows into the section and is used for hot water supply, Without lowering the water temperature in the hot water storage tank reserving the hot water temperature, i.e. without reducing the heat storage amount of the hot water storage tank, it is possible to boiling operation a large capacity and high efficiency.

  In the heat pump water heater of the present invention, the hot water heated by the water side pipe of the hot water heat exchanger is supplied through the outlet side opening of the first hot water storage pipe and the inlet side opening of the first hot water pipe, The hot water temperature in the hot water storage tank does not decrease even when a large capacity operation with a low boiling temperature is performed. Therefore, it does not have a dedicated direct hot water supply circuit, and even when the capacity of the hot water storage tank is relatively small, a large capacity and highly efficient boiling operation is possible, and a compact and heat pump water heater that does not run out can be provided. is there.

A first invention is a refrigerant circuit formed by annularly connecting a refrigerant side pipe, an expansion valve, and an evaporator of a compressor, a hot water supply heat exchanger, a hot water storage tank, a water circulation pump, and a water side of the hot water supply heat exchanger. In a heat pump water heater comprising a hot water storage circuit formed by connecting pipes in a ring shape, and a hot water supply circuit for supplying hot water at a predetermined temperature by mixing hot water in the hot water storage tank and water in the water supply pipe, The outlet side opening of the first hot water storage pipe for returning the hot water heated by the water side pipe to the upper part of the hot water storage tank and the inlet side opening of the first hot water supply pipe for taking out hot water from the upper part of the hot water storage tank are substantially opposed to each other. Even if the temperature of the hot water discharged from the outlet side opening of the first hot water storage pipe is low, it flows directly into the inlet side opening of the first hot water supply pipe and is used for hot water supply. Reduce the temperature of hot water in hot water storage tanks that store hot water No, i.e. without reducing the heat storage amount of the hot water storage tank, it is possible to boiling operation a large capacity and high efficiency.

  In the second invention, in particular, the outlet side opening of the first hot water storage pipe of the first invention is arranged vertically above the inlet side opening of the first hot water supply pipe, and the outlet side opening of the first hot water storage pipe. Since the hot water coming out of the hot water can be reliably received at the opening on the inlet side of the first hot water supply pipe, a high-capacity and high-efficiency boiling operation can be performed without lowering the hot water temperature in the hot water storage tank.

  In particular, the third aspect of the invention is a comparatively manufactured product in which the outlet side opening of the first hot water storage pipe of the first invention and the inlet side opening of the first hot water supply pipe are arranged to face each other in the horizontal direction. However, it is possible to perform boiling operation with high capacity and high efficiency without lowering the hot water temperature in the hot water storage tank.

  In the fourth invention, in particular, the diameter of the inlet side opening of the first hot water supply pipe of any one of the first to third inventions is made larger than the diameter of the outlet side opening of the first hot water storage pipe. Thus, the hot water that has exited the opening on the outlet side of the first hot water storage pipe is prevented from staying in the hot water tank without entering the opening on the inlet side of the first hot water supply pipe, and the hot water temperature in the hot water storage tank is not lowered. A large-capacity and high-efficiency boiling operation is possible.

  In the fifth invention, in particular, the outlet side opening of the first hot water storage pipe of the fourth invention is inserted into the inlet side opening of the first hot water supply pipe, and the outlet side opening of the first hot water storage pipe is exited. Since hot water is reliably supplied through the opening on the inlet side of the first hot water supply pipe, high-capacity and high-efficiency boiling operation can be performed without lowering the temperature of the hot water in the hot water storage tank.

  In the sixth invention, in particular, the distance between the outlet side opening of the first hot water storage pipe of any one of the first to fourth inventions and the inlet side opening of the first hot water supply pipe is set to 100 mm or less. The hot water that has exited the opening on the outlet side of the first hot water storage pipe is prevented from staying in the hot water storage tank without entering the opening on the inlet side of the first hot water supply pipe, and has a high capacity without lowering the hot water temperature in the hot water storage tank. In addition, highly efficient boiling operation is possible.

  The seventh invention is particularly compact in that the heat pump water heater of any one of the first to sixth inventions has a maximum heating capacity of 8 to 12 kW and a hot water storage tank capacity of 100 to 150 L. In addition, a heat pump water heater that does not cause hot water shortage can be provided.

  In an eighth aspect of the invention, in particular, the refrigerant circuit according to any one of the first to seventh aspects of the invention is a supercritical heat pump cycle in which the refrigerant pressure on the high-pressure side is equal to or higher than the critical pressure, and the refrigerant is pressurized to the critical pressure or higher. The water in the water-side piping of the hot water heat exchanger is heated by the refrigerant, and since the refrigerant in the hot water heat exchanger is pressurized to a critical pressure or higher, heat is taken away by the water in the hot water heat exchanger. Even if the temperature drops, it does not condense. Therefore, it becomes easy to form a temperature difference between the refrigerant and water in the entire area of the hot water heat exchanger, and the heat exchange efficiency can be increased.

  The ninth aspect of the invention uses carbon dioxide as the refrigerant of the eighth aspect of the invention, and reduces the product cost and improves the reliability by using relatively inexpensive and stable carbon dioxide for the refrigerant. be able to. In addition, since carbon dioxide has an ozone depletion coefficient of zero and a global warming coefficient of about 1/700 of the alternative refrigerant HFC-407C, it can provide a heat pump water heater that is friendly to the global environment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a configuration diagram of a heat pump water heater in the first embodiment of the present invention.

  In FIG. 1, the heat pump water heater in the present embodiment includes a refrigerant circuit 6, a hot water storage circuit 14, and a hot water supply circuit 20, and the refrigerant circuit 6 is a refrigerant side pipe of the compressor 1 and the hot water supply heat exchanger 2. 2a, the expansion valve 3, and the evaporator 4 are connected in a ring shape. The evaporator 4 has a fan 5. Heat exchange is performed between the air supplied to the evaporator 4 by the fan 5 and the refrigerant in the evaporator 4, and the refrigerant is heated.

  The hot water storage circuit 14 is formed by annularly connecting the hot water storage tank 7, the water circulation pump 8, and the water side pipe 2 b of the hot water supply heat exchanger 2. The water at the bottom of the hot water storage tank 7 is transported to the water side pipe 2b of the hot water heat exchanger 2 by the water circulation pump 8, where it exchanges heat with the refrigerant in the refrigerant side pipe 2a of the hot water heat exchanger 2 and has its own high temperature. It becomes hot water and is returned to the upper part of the hot water storage tank 7 through the first hot water storage pipe 10. A water supply pipe 17 for supplying water to the hot water storage tank 7 is provided at the bottom of the hot water storage tank 7 via a pressure reducing valve 116, and a first hot water supply pipe 15 for extracting hot water from the hot water storage tank 7 is provided above the hot water storage tank 7. Each is connected to form a hot water supply circuit 20 for supplying hot water to a hot water supply terminal 19 such as a shower or a currant through the mixing valve 18. Residual hot water amount sensors 13 a, 13 b, and 13 c are installed on the side wall surface of the hot water storage tank 7, and the remaining hot water amount in the hot water storage tank 7 can be detected by measuring the wall surface temperature of the hot water storage tank 7.

  Further, the outlet side opening 10a of the first hot water storage pipe 10 and the inlet side opening 15a of the first hot water supply pipe 15 are arranged so as to be substantially opposed to each other with a gap of 100 mm or less in the hot water storage tank 7. is doing.

  11 is an incoming water temperature sensor that detects the temperature of water flowing into the hot water supply heat exchanger 2, and 12 is a hot water temperature sensor that detects the temperature of water flowing out of the hot water supply heat exchanger 2. Reference numeral 9 denotes a three-way switching valve for switching to supply hot water flowing out from the hot water supply heat exchanger 2 to either the upper part or the lower part of the hot water storage tank 7.

  Conventionally, the refrigerant circuit 6 and the hot water storage tank 7 are housed in separate units (referred to as a separate type), but in the present embodiment, the refrigerant circuit 6, the hot water storage circuit 14, and the hot water supply circuit 20 are the same. It is set as the structure (it calls an integrated type) accommodated in the cabinet (not shown).

  Thereby, the space saving by the downsizing of the heat pump water heater and the workability improvement of the installation piping work are aimed at. Moreover, in order to make the heat pump water heater compact and prevent the hot water from running out, it is preferable to set the capacity of the hot water storage tank 7 to 100 to 150 L and the maximum heating capacity of the heat pump to about 8 to 12 kW.

  When a hot water supply load is generated, the hot water in the hot water storage tank 7 is mixed with water from the water supply pipe 17 through the first hot water supply pipe 15 through the first hot water supply pipe 15 from the inlet side opening 15a of the first hot water supply pipe 15 and is predetermined. Hot water having a temperature (about 38 ° C. to 48 ° C.) is supplied from the hot water supply terminal 19. In addition, when the remaining hot water amount in the hot water storage tank 7 is less than a predetermined value (for example, when the detected temperature of the remaining hot water amount sensor 13c is lower than 45 ° C.), the hot water has run out (the hot water in the hot water storage tank 7 has In order to prevent it from disappearing, perform a heating operation with a heat pump. When the hot water in the hot water storage tank 7 is further reduced (for example, when the temperature detected by the remaining hot water amount sensor 13b is lower than 45 ° C.), the heat pump is operated at the maximum heating capacity (for example, 10 kW). It prevents hot water from running out.

  Note that if the heating capacity of the heat pump is increased while the boiling temperature is fixed (for example, 85 ° C.), the current value and discharge pressure of the compressor 1 exceed the allowable range, so the heat pump is operated at the maximum heating capacity. When performing, the boiling temperature is set lower than usual (for example, 42 ° C. to 65 ° C.).

  About the heat pump water heater comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  During the winter season or a period when the hot water supply load is high in the intermediate period, a large amount of hot water (70 to 85 ° C.) is stored in the hot water storage tank 7. By storing heat at a high temperature, the capacity of the hot water storage tank 7 can be reduced. On the other hand, at a time when the hot water supply load is low, such as in the summer, by storing a relatively small amount of hot water (65 ° C.) in the hot water storage tank 7, the operation efficiency of the heat pump is improved and unnecessary heating operation is prevented. be able to.

  When the amount of remaining hot water in the hot water storage tank 7 is lower than a predetermined amount (for example, when the detected temperature of the remaining hot water amount sensor 13b is lower than 45 ° C.), the heat pump is set to the maximum heating capacity (for example, 10 kW), Operate at 42 ° C to prevent running out of hot water.

  At this time, the outlet side opening 10a of the first hot water storage pipe 10 and the inlet side opening 15a of the first hot water supply pipe 15 are disposed so as to be substantially opposed to each other inside the hot water storage tank 7, so that the heat pump unit The boiled water at 42 ° C. is used for hot water supply via the inlet side opening 15a of the first hot water supply pipe 15 immediately after flowing into the hot water storage tank 7 from the outlet side opening 10a of the first hot water storage pipe 10. For this reason, the relatively hot (70 to 85 ° C.) hot water stored in the upper part of the hot water storage tank 7 and the 42 ° C. hot water boiled by the heat pump unit are mixed together, so that the temperature of the hot water in the upper part of the hot water storage tank 7 is increased. It is possible to prevent the decrease.

  Even if the amount of remaining hot water in the hot water storage tank 7 is large, if it is known in advance that a large amount of hot water will be used, such as filling a bathtub (not shown), the heat pump unit is set to the maximum at the start of hot water supply. You may drive with your ability. Moreover, in the said embodiment, although the maximum heating capability of the heat pump unit was 10 kW and the boiling temperature was 42 ° C., these values had a certain range (for example, the maximum heating capability of the heat pump unit was about 8 to 12 kW, The boiling temperature may be about 38 to 65 ° C.).

  In the said embodiment, although the exit side opening part 10a of the 1st hot water supply piping 10 was arrange | positioned just above the entrance side opening part 15a of the 1st hot water supply piping 15, ie, perpendicular | vertical upper direction, it shows to Fig.2 (a). As described above, the outlet side opening 10a of the first hot water storage pipe 10 and the inlet side opening 15a of the first hot water supply pipe 15 may be arranged to face each other in the horizontal direction. In this case, manufacturing becomes relatively easy.

  In addition, as shown in FIG. 2 (b), if the pipe diameter of the inlet side opening 15 a of the first hot water supply pipe 15 is made larger than the pipe diameter of the outlet side opening 10 a of the first hot water storage pipe 10, the heat pump unit. The hot water boiled in is used for hot water supply through the outlet side opening 10a of the first hot water storage pipe 10, the hot water storage tank 7, and the inlet side opening 15a of the first hot water supply pipe 15 more reliably. 7 It can prevent that the temperature of the hot water of the upper part falls.

  Furthermore, as shown in FIG. 2C, if the outlet side opening 10a of the first hot water storage pipe 10 is inserted into the inlet side opening 15a of the first hot water supply pipe 15, the first hot water storage pipe 10 Since the hot water that has exited the outlet side opening 10a is reliably supplied through the inlet side opening 15a of the first hot water supply pipe 15, it has a large capacity and high efficiency without boiling down the hot water temperature in the hot water storage tank 7. Raising operation is possible.

  Further, in the present embodiment, carbon dioxide is used as the refrigerant, and the cycle of the refrigerant circuit 6 is a supercritical heat pump cycle in which the refrigerant pressure on the high pressure side is equal to or higher than the critical pressure. Of course, the refrigerant pressure on the high pressure side is critical. A heat pump cycle under pressure may be used. In this case, chlorofluorocarbon, ammonia, or the like may be used as the refrigerant.

  As described above, the heat pump water heater according to the present invention can perform a high-capacity and high-efficiency boiling operation without lowering the hot water temperature in the hot water storage tank, and has a relatively small capacity of the hot water storage tank. It is extremely effective for water heaters.

Configuration diagram of heat pump water heater in Embodiment 1 of the present invention (A) The block diagram which shows the other example of piping in the hot water storage tank of the heat pump water heater (b) The block diagram which shows the other example of piping in the hot water storage tank (c) The other example of piping in the hot water storage tank is shown Partial enlarged sectional view Configuration diagram of conventional heat pump water heater

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 Hot-water supply heat exchanger 2a Refrigerant-side piping of hot-water supply heat exchanger 2b Water-side piping of hot-water supply heat exchanger 3 Expansion valve 4 Evaporator 5 Fan 6 Refrigerant circuit 7 Hot water storage tank 8 Water circulation pump 9 Three-way switching valve 10 1st Hot water storage pipe 10a Outlet side opening of first hot water storage pipe 11 Incoming water temperature sensor 12 Hot water temperature sensor 13a, 13b, 13c Remaining hot water amount sensor 14 Hot water storage circuit 15 First hot water supply pipe 15a Inlet side opening of first hot water supply pipe 16 Pressure reducing valve 17 Water supply pipe 18 Mixing valve 19 Hot water supply terminal 20 Hot water supply circuit

Claims (9)

A refrigerant circuit formed by annularly connecting the refrigerant side piping of the compressor, the hot water supply heat exchanger, the expansion valve, and the evaporator, and a hot water storage tank, a water circulation pump, and the water side piping of the hot water supply heat exchanger are connected annularly. In the heat pump water heater comprising a hot water storage circuit formed and a hot water supply circuit that mixes hot water in the hot water storage tank and water in the water supply pipe to supply hot water at a predetermined temperature, the heat pump is heated by the water side pipe. The outlet side opening of the first hot water storage pipe returning the hot water to the upper part of the hot water storage tank and the inlet side opening of the first hot water supply pipe for taking out the hot water from the upper part of the hot water storage tank are arranged so as to be substantially opposed to each other. A heat pump hot water supply machine. The heat pump water heater according to claim 1, wherein the outlet side opening of the first hot water storage pipe is arranged vertically above the inlet side opening of the first hot water supply pipe. The heat pump water heater according to claim 1, wherein the outlet side opening of the first hot water storage pipe and the inlet side opening of the first hot water supply pipe are arranged to face each other in the horizontal direction. The heat pump hot water supply according to any one of claims 1 to 3, wherein the pipe diameter of the inlet side opening of the first hot water supply pipe is larger than the pipe diameter of the outlet side opening of the first hot water storage pipe. Machine. The heat pump water heater according to claim 4, wherein the outlet side opening of the first hot water storage pipe is inserted into the inlet side opening of the first hot water supply pipe. The heat pump water heater according to any one of claims 1 to 4, wherein a distance between an outlet side opening of the first hot water storage pipe and an inlet side opening of the first hot water supply pipe is set to 100 mm or less. The maximum heating capacity of the heat pump is 8 to 12 kW, and the capacity of the hot water storage tank is 100 to 150 L, The heat pump water heater according to any one of claims 1 to 6. The refrigerant circuit is a supercritical heat pump cycle in which a refrigerant pressure on a high-pressure side becomes equal to or higher than a critical pressure, and heats water in a water-side pipe of a hot water supply heat exchanger with a refrigerant whose pressure is increased to the critical pressure or higher. The heat pump water heater according to any one of 7. The heat pump water heater according to claim 8, wherein carbon dioxide is used as the refrigerant.

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