JP2009281629A - Heat pump water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat pump water heater with high efficiency and excellent energy saving property. <P>SOLUTION: The heat pump hot water heater includes a heat pump cycle 20 constituted by connecting a compressor 21, a hot water supply heat exchanger 22, an expansion valve 23 and an evaporator 24 by a pipe 26; and a heat storage unit 31 storing heat by circulating refrigerant heated by the heat pump cycle 20. The heat storage unit 31, a circulation pump 38, and the hot water supply heat exchanger 22 are connected by a pipe, and the heat pump cycle 20 is started to operate when a hot water supply load occurs. Since hot water heated by the heat pump cycle 20 is preferentially used for hot water supply, upon occurrence of the hot water supply load, while complementing the hot water supply with hot water made by heat exchange in the heat storage unit 21, water entering to the heat exchanger 22 is not return water from the unit 31 but water supplied from a water pipe or the like. Therefore, the operation can be performed in a highly efficient cycle without rise of water temperature, and excellent energy saving property can be obtained. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a heat pump water heater.

  Conventionally, various hot water supply apparatuses using a heat pump cycle have been proposed, and there are those shown in FIG. 3 (see, for example, Patent Document 1).

  FIG. 3 is a configuration diagram of a conventional heat pump water heater described in Patent Document 1. In FIG. In FIG. 3, a refrigerant circulation circuit including a compressor 1, a heat storage device 2, a heat storage heat transfer tube 3, an expansion device 4, and an evaporator 5, a heat storage device 2, a water supply pipe 11, a hot water transfer heat transfer pipe 12, and a flow control valve 13. And a hot water supply circuit to which a mixing valve 14, a bypass pipe 15, and a hot water supply pipe 16 are connected.

  When performing heat storage, the high-temperature and high-pressure superheated gas discharged from the compressor 1 flows into the heat storage device 2 and exchanges heat with the heat storage material (not shown) of the heat storage device 2 when flowing through the heat storage heat transfer tube 3. Go to cool and condense. The refrigerant that has exited the heat storage heat transfer tube 3 is decompressed by the expansion device 4 and flows into the evaporator 5, where it absorbs atmospheric heat to evaporate and returns to the compressor 1.

  When the heat storage operation is terminated, a high pressure cutoff pressure switch 6 is provided on the discharge side of the compressor 1, and the operation of the compressor 1 is stopped when the high pressure of the refrigerant circuit reaches a predetermined value. The predetermined value of the high pressure is the high pressure of the refrigerant when the temperature of the heat storage material reaches the temperature immediately after the end of heat storage in the latent heat region.

When hot water is supplied, one of the tap water passes through the water supply pipe 11 and is introduced into the heat transfer pipe 12 for hot water, and heat exchange with the heat storage material of the heat storage device 2 is performed to heat the tap water. The heated tap water passes through the flow control valve 13 and flows into the mixing valve 14. The other of the tap water passes through the water supply pipe 11 and the bypass pipe 15 and flows into the mixing valve 14. The mixing valve 14 mixes to a desired temperature and supplies hot water from the hot water supply pipe 16.
JP 2004-101031 A

  However, in the configuration of the conventional heat pump hot water supply device, there is no description about the operation start condition of the heat pump cycle in particular. For example, when the temperature of the heat storage device 2 is low, the operation of the heat pump cycle is started and the heat storage device 2 When heat storage is estimated and heat storage operation is continued, the outlet temperature of the heat storage heat transfer tube 3 rises, resulting in poor operation efficiency.

  This invention solves the said conventional subject, and it aims at providing the heat pump hot-water supply apparatus which was drive | operated by the highly efficient cycle and was excellent in energy-saving property.

In order to solve the conventional problems, a heat pump hot water supply apparatus of the present invention includes a heat pump cycle configured by connecting a compressor, a hot water heat exchanger, a throttling device, and an evaporator with piping, and the heat pump cycle. A heat storage unit that stores heat by circulating the refrigerant that has been heated, and connects the heat storage unit, the circulation pump, and the heat exchanger for hot water supply with piping, and the heat pump cycle when a hot water supply load is generated When a hot water supply load occurs, the hot water heated by the heat pump cycle is preferentially used for hot water supply,
The water that enters the heat exchanger for hot water supply is not the return water from the heat storage unit, but the water supplied from the water pipes, etc., because the water is supplemented with hot water produced by heat exchange with the heat storage unit, and the water temperature rises. There is nothing, and it operates with a high-efficiency cycle and is excellent in energy saving.

  The heat pump hot water supply apparatus of the present invention uses hot water heated in the heat pump cycle preferentially for hot water supply when a hot water supply load is generated, and supplements hot water with hot water produced by heat exchange in the heat storage unit. The temperature of water entering the exchanger does not rise, it operates with a high-efficiency cycle, and it excels in energy saving.

  1st invention stores heat by circulating the refrigerant | coolant heated using the heat pump cycle comprised by connecting a compressor, the hot water heat exchanger, the expansion device, and the evaporator with piping, and the said heat pump cycle A heat storage unit that connects the heat storage unit, a circulation pump, and the heat exchanger for hot water supply with piping, and starts operation of the heat pump cycle when a hot water supply load is generated. In this case, the hot water heated in the heat pump cycle is preferentially used for hot water supply and supplemented with hot water produced by heat exchange in the heat storage unit, so that the water entering the hot water heat exchanger is returned from the heat storage unit. It is not water but water supplied from a water pipe or the like, the water temperature does not rise, it operates with a high-efficiency cycle, and is excellent in energy saving.

  In particular, the second invention continues for a predetermined time from the start of operation of the heat pump cycle to the stop even when the hot water supply load of the first invention is stopped. Although the loss ratio increases, by controlling to stop the operation of the heat pump cycle after continuing for a predetermined time, it is possible to operate with a more efficient cycle and to have excellent energy saving performance.

  In particular, the third aspect of the invention provides an incoming water temperature detecting means at the water inlet of the hot water supply heat exchanger of the first or second aspect of the invention, and the incoming water detected by the incoming water temperature detecting means even when the hot water supply load is stopped. The operation of the heat pump cycle is continued until the temperature reaches a predetermined temperature, and the inefficient operation at a high incoming water temperature can be reduced.

  The fourth aspect of the invention is particularly provided with an outside air temperature detecting means for detecting the suction temperature of the evaporator of the first or second aspect of the invention, and even if the hot water supply load is stopped, the incoming water temperature detected by the incoming water temperature detecting means is The operation of the heat pump cycle is continued until the predetermined temperature determined according to the outside air temperature detected by the outside air temperature detecting means is reached, which reduces the inefficient operation at high incoming water temperature. Are better.

  In the fifth invention, in particular, the heat storage unit according to any one of the first to fourth inventions is composed of a latent heat storage material and a liquid circulation path, and a latent heat storage material having a larger amount of heat storage per unit volume than water. Since it is employed, it is possible to reduce the size when storing the same amount of heat.

  In the sixth aspect of the invention, in particular, the refrigerant used in the heat pump cycle of any one of the first to fifth aspects is carbon dioxide, and the high pressure side is operated in a state exceeding the critical pressure. When it is realized with efficiency, and the refrigerant leaks to the outside, the influence on global warming is very small.

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

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

  In FIG. 1, the refrigeration circuit of the heat pump hot-water supply apparatus in the 1st Embodiment of this invention is demonstrated.

  In the heat pump cycle 20, a compressor 21, a hot water supply heat exchanger 22, an expansion valve 23 that is a throttling device, and an evaporator 24 are connected by a pipe 26. Further, a fan 25 for blowing air to the evaporator 24 is provided. Further, an outside air temperature detecting means 24A for detecting the suction temperature of the evaporator 24 is provided.

  The heat pump hot water supply apparatus in the present embodiment preferably uses carbon dioxide as a refrigerant and is operated in a state where the critical pressure is exceeded on the high pressure side.

  Next, a hot water supply circuit of the heat pump hot water supply apparatus in the first embodiment of the present invention will be described.

  The heat storage unit 31 includes a latent heat storage material 32 and a liquid circulation path 33. The first bottom pipe 34 of the heat storage unit 31 is connected to a water supply pipe 36 such as a water pipe via a pressure reducing valve 35. In addition, on the inlet side of the water pipe 22 </ b> A of the hot water supply heat exchanger 22, an incoming water temperature detection means 22 </ b> B that detects the temperature of the water flowing into the hot water supply heat exchanger 22 is installed. The second bottom pipe 37 of the heat storage unit 31 is connected to the inflow side of the water pipe 22 </ b> A of the hot water supply heat exchanger 22 through the circulation pump 38 and is connected to the first upper pipe 39 of the heat storage unit 31. Yes. Moreover, the 2nd upper piping 40 of the thermal storage unit 31 is connected to faucets and bath terminals (not shown), such as a kitchen or a washroom.

  The controller 50 includes a compressor operation time detection means 51, a temperature detection means 52, and a compressor control means 53, and controls the stop timing of the compressor 21.

  Next, the heat storage operation of the heat pump water heater in the first embodiment of the present invention will be described.

  The compressor 21 starts and the heat pump cycle 20 starts operation. The refrigerant compressed by the compressor 21 dissipates heat in the hot water supply heat exchanger 22, is decompressed by the expansion valve 23, absorbs heat in the evaporator 24, and is sucked into the compressor 21 in a gas state. The fan 25 is set to a rotational speed corresponding to the operating state of the compressor 21.

  By the circulation pump 38, the water from the heat storage unit 31 passes through the second bottom pipe 37 of the heat storage unit 31, is led to the water pipe 22 </ b> A of the hot water supply heat exchanger 22, and is heated to high-temperature hot water. Flow into.

  Here, heat is exchanged with the latent heat storage material 32, and the temperature of the latent heat storage material 32 rises, and the high-temperature hot water that flows in becomes low-temperature water, circulates, and stores heat in the heat storage unit 31.

  FIG. 2 is a flowchart of operation control of the heat pump water heater in the first embodiment of the present invention.

  Next, operation control of the heat pump water heater in the first embodiment of the present invention will be described using the flowchart of FIG.

  First, the power is turned on (step 1), and then it is determined whether or not the heat storage operation mode is set (step 2). The heat storage operation mode is an operation mode in which heat is stored in the heat storage unit 31. In the case of Yes in step 2, the compressor 21 is turned on by the compressor control means 53 (step 3), and the heat pump cycle 20 starts operation. Then, heat is stored in the heat storage unit 31, and the operation is continued until the end condition is reached. Here, the end condition of the heat storage operation mode is omitted.

  Next, in the case of No in step 2, the compressor operating time Tc = 0 is set by the compressor operating time detecting means 51 (step 4). Next, whether hot water is supplied from the second upper pipe 40 or whether there is a hot water supply load, for example, by the output of a flow sensor (not shown) or a temperature sensor (not shown) attached to the second upper pipe 40 Is determined (step 5).

  In step 5, in the case of Yes, the compressor 21 is turned on by the compressor control means 53, the heat pump cycle 20 starts operation, and the compressor operation time Tc is added (step 6). Next, it is determined whether the hot water supply load is continued (step 7). When the hot water supply load is continued, the compressor 21 continues to operate and the compressor operation time Tc is added. When the hot water supply load is lost, that is, in the case of No in Step 7, the outside air temperature detecting means 24A which is one of the temperature detecting means 52 detects the outside air temperature To, and the other incoming water temperature detecting means 22B detects the incoming water temperature Tin. (Step 8). Next, it is determined whether the compressor operating time Tc is equal to or longer than a predetermined time (for example, 10 minutes) and the incoming water temperature Tin is equal to or higher than a predetermined temperature shown in (Table 1) (step 9).

  In the case of No in step 9, the process returns to step 6, the compressor operation time Tc is added, and the compressor 21 continues to operate until it becomes Yes in step 9. In the case of Yes in step 9, the compressor 21 is turned off by the compressor control means 53, the heat pump cycle 20 stops operating, and the compressor operating time Tc is reset to 0 (step 10).

  Here, although the rotational speed control of the compressor 1 is not particularly described, an appropriate rotational speed of the compressor 1 is set according to the incoming water temperature and the outside air temperature. Further, although the opening degree control of the expansion valve 23 is not particularly described, an appropriate target discharge temperature is set according to the incoming water temperature and the outside air temperature, and the expansion valve 23 is opened so that the target discharge temperature is reached. The degree is controlled.

  Accordingly, when a hot water supply load is generated, the hot water heated in the heat pump cycle 20 is preferentially used for hot water supply, and supplemented with hot water produced by heat exchange in the heat storage unit 31 to supply hot water. The incoming water is not the return water from the heat storage unit 31 but water supplied from a water pipe or the like, and the water temperature does not rise, operates in a highly efficient cycle, and is excellent in energy saving. In addition, since the ratio of the rising loss increases when the operation time of the heat pump cycle 20 is short, after the predetermined time (for example, 10 minutes) continues, the inflow operation is detected and the inefficient operation at the high inflow temperature is reduced. In addition, because it is possible to operate, it can be operated in a highly efficient cycle and is excellent in energy saving.

In this embodiment, the case where carbon dioxide is used as the refrigerant has been described. However, other refrigerants such as R410A refrigerant and HC refrigerant may be used as the refrigerant.

  In this embodiment, the latent heat storage agent is not particularly described, but one type of latent heat storage agent or two or more types of latent heat storage agents having different melting points may be filled.

  In the present embodiment, the heat pump hot water supply apparatus provided with one heat pump cycle 20 has been described as an example, but two or more heat pump cycles 20 may be used.

  As described above, the heat pump hot water supply apparatus according to the present invention can easily store heat in the heat storage unit, and thus can be applied to uses such as heating using the amount of stored heat.

The circuit block diagram of the heat pump hot-water supply apparatus in Embodiment 1 of this invention Flow chart of operation control of the heat pump water heater Configuration diagram of conventional heat pump water heater

Explanation of symbols

20 heat pump cycle 21 compressor 22 heat exchanger for hot water supply 23 expansion valve (throttle device)
24 Evaporator 26 Piping 31 Heat Storage Unit 38 Circulation Pump

Claims (6)

A heat pump cycle configured by connecting a compressor, a heat exchanger for hot water supply, an expansion device, and an evaporator with piping, and a heat storage unit that stores heat by circulating a refrigerant heated using the heat pump cycle. The heat pump hot water supply apparatus, wherein the heat storage unit, the circulation pump, and the hot water heat exchanger are connected by piping, and the operation of the heat pump cycle is started when a hot water supply load is generated. 2. The heat pump hot water supply device according to claim 1, wherein even if the hot water supply load is stopped, the operation continues for a predetermined time from the start of operation of the heat pump cycle to the stop. Even if the hot water load is stopped, the operation of the heat pump cycle is continued until the incoming water temperature detected by the incoming water temperature detecting means reaches a predetermined temperature even if the hot water supply load is stopped. The heat pump water heater according to claim 1 or 2. An outside air temperature detecting means for detecting the suction temperature of the evaporator is provided, and even if the hot water supply load is stopped, the incoming water temperature detected by the incoming water temperature detecting means is determined according to the outside air temperature detected by the outside air temperature detecting means. The heat pump hot water supply device according to claim 1 or 2, wherein the operation of the heat pump cycle is continued until a predetermined temperature is reached. The heat storage unit according to any one of claims 1 to 4, wherein the heat storage unit includes a latent heat storage material and a liquid circulation path. The heat pump hot water supply device according to any one of claims 1 to 5, wherein the refrigerant used in the heat pump cycle is carbon dioxide, and the high pressure side is operated in a state exceeding a critical pressure.

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