JP2008261557A - Heat pump water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat pump water heater having an inexpensive configuration and being easily achieved as a product. <P>SOLUTION: The heat pump water heater is provided with a refrigeration cycle unit 1 constituted by annularly connecting a compressor 2, a heat exchanger 3 for hot water supply, a decompression device 4 and an air heat exchanger 6; an internal heat exchanger 8 for performing heat exchange between a refrigerant from a refrigerant outlet side of the heat exchanger 3 for hot water supply to an inlet side of the decompression device 4 and a refrigerant from a refrigerant outlet side of the air heat exchanger 6 to a suction side of the compressor 2; and a bypass circuit 28 for connecting the refrigerant outlet side of the heat exchanger 3 for hot water supply to the outlet side of the decompression device 4. Water is circulated from a bottom part of a storage tank 11 in the heat exchanger 3 for hot water supply by a boiling-up pump 10, and the water inside the storage tank 11 is heated and stored as hot water. The heat pump water heater is further provided with a heat exchange quantity control means 29 for controlling the heat exchange quantity of the internal heat exchanger 8 based on at least one of flowing-in water temperature of water flowing in the heat exchanger 3 for hot water supply and the outside air temperature. Thus, the heat exchange quantity of the internal heat exchanger 8 can be accurately controlled in a more inexpensive method. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat pump water heater that supplies hot water by storing heated hot water in a hot water storage tank.

  As a conventional heat pump water heater of this type, there is one shown in FIG. 5 (see, for example, Patent Document 1).

  FIG. 5 is a circuit diagram of a conventional heat pump water heater described in Patent Document 1, and FIG. 6 is a bypass valve control flow diagram of the heat pump water heater.

  In FIG. 5, a refrigeration cycle unit 1 of a conventional heat pump water heater is a heating source that heats and heats water, and includes a compressor 2, a hot water heat exchanger 3, a decompressor 4, an air The heat exchanger 6 is connected in a ring shape.

  Further, internal heat exchange is performed to exchange heat between the refrigerant from the refrigerant outlet side of the hot water supply heat exchanger 3 to the inlet side of the decompression device 4 and the refrigerant from the refrigerant outlet side of the air heat exchanger 6 to the suction side of the compressor 2. The bypass valve 5 is provided in the bypass circuit 27 of the internal heat exchanger 8 that connects the refrigerant outlet side of the hot water supply heat exchanger 3 and the outlet side of the decompression device 4.

  The air heat exchanger 6 performs heat exchange between the outside air blown by the blower 7 and the refrigerant flowing inside.

  Further, the hot water storage unit 9 that circulates water and stores hot water heated by the refrigeration cycle unit 1 and supplies hot water circulates water from the bottom of the hot water storage tank 11 to the hot water supply heat exchanger 3 by the boiling pump 10. Thus, the water in the hot water storage tank 11 is heated, and hot water is stored in the hot water storage tank 11.

  In the boiling operation, the high-temperature and high-pressure gas refrigerant pressurized by the compressor 2 is sent to the hot water supply heat exchanger 3. Heat exchange with the cold water at the bottom of the hot water storage tank 11 conveyed by the boiling pump 10 becomes a low-temperature refrigerant. Then, the refrigerant radiated to the cold water in the hot water supply heat exchanger 3 is decompressed by the decompression device 4 to become a two-phase refrigerant, and is sent to the air heat exchanger 6 to exchange heat with the atmosphere to become a low-temperature gas refrigerant and compressed. Circulate to machine 2.

  On the other hand, the cold water at the bottom of the hot water storage tank 11 is conveyed to the hot water supply heat exchanger 6 by the boiling pump 9 and absorbs the heat of the refrigerant to become hot water, passes through the boiling pipe 13 and the upper part of the hot water storage tank 11. Sent to. At this time, the hot water is not mixed with the water due to the density difference, and the hot water is stacked from the upper part of the hot water storage tank 11 so that the hot water is accumulated in the hot water storage tank 11.

  At this time, the controller 34 performs processing as shown in FIG.

The pressure signal from the pressure sensor 35 that detects the discharge pressure of the compressor 2, the signal from the discharge temperature sensor 36 that detects the discharge temperature of the compressor 2, and the load applied to the air heat exchanger 6, for example, an air heat exchanger A signal from the evaporator temperature sensor 37 that is detected as the refrigerant temperature at the 6 outlets is input (STEP 50). Based on these signals, an optimum pressure that maximizes the COP is calculated, and whether or not the high pressure has risen to a dangerous area. Whether or not the discharge temperature has risen to the dangerous temperature is determined (STEP 51), the opening degree of the bypass valve 5 is determined based on the determination, and the opening degree of the bypass valve 5 is set to such an opening degree. Is controlled (STEP 52).
JP 11-193967 A

  However, in the configuration of the conventional heat pump water heater, the pressure sensor 35 is used to control the heat exchange amount of the internal heat exchanger 8, but the pressure sensor 35 is a high pressure that is used at a critical pressure or higher, for example. In the case of carbon dioxide gas or the like, the accuracy of the pressure sensor 35 is poor, and the pressure sensor 35 with improved accuracy is expensive. Therefore, it is rare that the pressure sensor 35 is attached to a heat pump water heater that is currently commercialized. is there.

  Therefore, there is a problem that it is not easy to control the heat exchange amount of the internal heat exchanger 8 using the pressure sensor 35.

  The present invention solves the above-described conventional problems, and uses a temperature sensor instead of a pressure sensor to control the amount of heat exchange of the internal heat exchanger, that is, accurately controls in a less expensive manner. An object of the present invention is to provide a heat pump water heater that can be easily realized.

  In order to solve the above-described conventional problems, a heat pump water heater of the present invention includes a refrigeration cycle unit configured by connecting a compressor, a hot water heat exchanger, a decompression device, and an air heat exchanger in an annular shape, and the hot water supply An internal heat exchanger for exchanging heat between the refrigerant from the refrigerant outlet side of the heat exchanger to the inlet side of the decompression device and the refrigerant from the refrigerant outlet side of the air heat exchanger to the suction side of the compressor; A bypass circuit connecting the refrigerant outlet side of the heat exchanger and the outlet side of the decompression device, and circulating water through the hot water heat exchanger from the bottom of the hot water tank by a boiling pump, In a heat pump water heater for heating hot water in the hot water storage tank and storing hot water in the hot water storage tank, the internal heat exchanger is controlled by at least one of an incoming water temperature flowing into the hot water heat exchanger and an outside air temperature. Which was provided with a heat exchange quantity control means for controlling the amount of heat exchange, you are possible to control the amount of heat exchange accurately internal heat exchanger in a more inexpensive way.

  The heat pump water heater of the present invention does not use an expensive pressure sensor, but can control the heat exchange amount of the internal heat exchanger using a temperature sensor, that is, can be accurately controlled by a cheaper method. An easy heat pump water heater can be provided.

  According to a first aspect of the present invention, there is provided a refrigeration cycle unit configured by annularly connecting a compressor, a hot water supply heat exchanger, a decompression device, and an air heat exchanger, and the decompression device from the refrigerant outlet side of the hot water supply heat exchanger. An internal heat exchanger that exchanges heat between the refrigerant up to the inlet side and the refrigerant from the refrigerant outlet side of the air heat exchanger to the suction side of the compressor, the refrigerant outlet side of the hot water supply heat exchanger, and the decompression device A bypass circuit connected to the outlet side, and by circulating water through the hot water heat exchanger from the bottom of the hot water storage tank by means of a boiling pump, the water in the hot water storage tank is heated and hot water is supplied to the hot water storage tank. In the heat pump water heater to be stored inside, a heat exchange amount control means is provided for controlling the heat exchange amount of the internal heat exchanger according to at least one of an incoming temperature of water flowing into the hot water heat exchanger and an outside air temperature. Food , It is possible to control the amount of heat exchange accurately internal heat exchanger in a more inexpensive way.

  In the second invention, in particular, a bypass valve is arranged in the bypass circuit of the first invention, and the heat exchange amount control means controls the heat exchange amount of the internal heat exchanger by adjusting the opening degree of the bypass valve. Thus, the heat exchange amount of the internal heat exchanger can be accurately controlled by a cheaper method.

  In the third invention, in particular, the heat pump water heater of the first or second invention uses a refrigerant used at a critical pressure or higher, and the refrigerant flowing through the hot water heat exchanger is higher than the critical pressure by a compressor. Therefore, it does not condense even if the temperature drops due to heat removal from the hot water supply heat exchanger. Therefore, it becomes easy to form a temperature difference between the refrigerant and water in the entire hot water supply heat exchanger, and the heat exchange efficiency can be increased.

  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 circuit diagram of a heat pump water heater in the first embodiment of the present invention, FIG. 2 is a relationship diagram of the opening degree of the bypass valve 5 and the COP of the heat pump water heater, and FIG. 3 is the heat pump water heater. FIG. 4 is a bypass valve control flow diagram of the heat pump water heater.

  The heat pump water heater in the present embodiment includes a hot water storage unit 9 having a hot water storage tank 11 in which low temperature hot water and high temperature hot water are stored in a layered state, and a refrigeration cycle that heats and heats the water in the hot water storage tank 11. The unit 1 is configured to store hot water that has been boiled in a hot water storage tank 11 and use it for hot water supply.

  First, the configuration of the refrigeration cycle unit 1 will be described.

  The refrigeration cycle unit 1 includes a compressor 2 that compresses a refrigerant, a hot water supply heat exchanger 3 that cools the refrigerant, a decompression device 4 that decompresses the refrigerant, and an air heat exchanger 6 that evaporates and evaporates the refrigerant. Yes.

  The compressor 2 is connected to the pressure reducing device 4 through the hot water supply heat exchanger 3 from the discharge side, and further connected to the suction side of the compressor 2.

  Further, internal heat exchange is performed to exchange heat between the refrigerant from the refrigerant outlet side of the hot water supply heat exchanger 3 to the inlet side of the decompression device 4 and the refrigerant from the refrigerant outlet side of the air heat exchanger 6 to the suction side of the compressor 2. And a bypass circuit 28 of the internal heat exchanger 8 that connects the refrigerant outlet side of the hot water supply heat exchanger 3 and the outlet side of the pressure reducing device 4 is provided, and the bypass valve 5 is provided in the middle of the bypass circuit 28. Is provided.

  In this refrigeration cycle unit 1, carbon dioxide gas is used as the refrigerant, and the refrigerant compressed by the compressor 2 enters the hot water supply heat exchanger 3 as a high-temperature and high-pressure refrigerant in a supercritical state. Dissipate heat to cool. Thereafter, the pressure is reduced in the pressure reducing device 4 to become low-temperature and low-pressure wet steam, and the air heat exchanger 6 exchanges heat with outside air to evaporate and return to the compressor 2. At this time, heat exchange with the outside air is promoted by the blower 7. In addition, an outside air temperature sensor 31 for detecting the outside air temperature is installed.

  The heat exchange amount control means 29 operates by determining the opening degree of the bypass valve 5 from the detected temperature of the outside air temperature sensor 31 and the detected temperature of the incoming water temperature sensor 15 that detects the incoming temperature of the water entering the hot water supply heat exchanger 3. It is something to be made.

  For example, an inexpensive thermistor may be used as the outside air temperature sensor 31 and the incoming water temperature sensor 15.

  On the other hand, as a configuration related to boiling of hot water, the boiling pipe 13 is connected from the lower part of the hot water storage tank 11 to the hot water supply heat exchanger 3 of the refrigeration cycle unit 1 and is connected to the upper part of the hot water storage tank 11.

  The upper part of the hot water storage tank 11 to which the boiling pipe 13 is connected is sufficient if the hot water is on the high temperature layer side of the hot water storage tank 11, and the lower part of the hot water storage tank 11 is on the low temperature layer side of the hot water storage tank 11. If it is.

  In order to send hot water from the hot water storage tank 11 to the refrigeration cycle unit 1 and return it to the hot water storage tank 11, a boiling pump 10 capable of arbitrarily changing the output is provided in the middle of the boiling pipe 13.

  In addition, a water temperature sensor 15 that detects the temperature of the low-temperature hot water before heating in the refrigeration cycle unit 1 is detected in the vicinity of the inlet side of the hot water supply heat exchanger 3 of the boiling pipe 13. A hot water temperature sensor 16 is provided in the vicinity of the outlet of the hot water supply heat exchanger 3 of the boiling pipe 13.

  And in order to grasp | ascertain the temperature distribution of the hot water storage tank 11, the hot water storage temperature detection means 12a-12d is provided in the orthogonal | vertical direction of an outer wall surface.

  Since the supplied water expands when heated by the refrigeration cycle unit 1, the pressure relief valve 14 is placed near the top of the hot water storage tank 11 so as not to exceed the pressure resistance of the hot water storage tank 11 or the water utilization circuit. The pressure relief valve 14 is connected to a drain pipe 26 for draining the expanded water.

  As a configuration relating to hot water supply, a water supply pipe 19 for supplying water from a water supply source (not shown) is connected to the bottom of the hot water storage tank 11, and the water supply pipe 19 is decompressed to an appropriate pressure by a pressure reducing valve 20. To be supplied with water.

  A hot water supply pipe 21 for discharging the hot water stored in the hot water tank 11 and using it for hot water supply is connected to the upper part of the hot water storage tank 11, and a water supply bypass pipe 22 from the water supply pipe 19 is connected in the middle thereof. Further, a hot water supply mixing valve 23 capable of mixing high temperature water from the hot water supply pipe 21 and low temperature water from the water supply bypass pipe 22 at an arbitrary ratio is provided.

  A hot water supply temperature sensor 25 is provided on the downstream side of the hot water supply mixing valve 23 to detect the mixed hot water supply temperature, and a hot water supply terminal 24 typified by a faucet or a shower is connected to the tip thereof.

  The operation and action of the heat pump water heater in the present embodiment configured as described above will be described.

  In the boiling operation, the high-temperature and high-pressure gas refrigerant pressurized by the compressor 2 is sent to the hot water supply heat exchanger 3. Heat exchange with the cold water at the bottom of the hot water storage tank 11 conveyed by the boiling pump 10 becomes a low-temperature refrigerant. And the refrigerant | coolant which thermally radiated to cold water with the heat exchanger 3 for hot water supply is pressure-reduced by the decompression device 4, and becomes a two-phase refrigerant. Then, it is sent to the air heat exchanger 6 to exchange heat with the atmosphere and becomes a low-temperature gas refrigerant, which is circulated to the compressor 2.

  At this time, the heat exchange amount control means 29 determines the opening degree of the bypass valve 5 in order to optimally control the COP and operates the opening degree.

  Next, the determination of the opening degree of the bypass valve 5 will be described in more detail.

  FIG. 2 shows a relationship between the degree of opening of the bypass valve 5 and the COP measured under conditions of constant water temperature and outside air temperature. As shown in FIG. 2, it can be seen that the COP is maximized at a certain opening degree of the bypass valve 5 under a certain condition.

  FIG. 3 shows a relationship diagram between the incoming water temperature at which COP is maximized, the outside air temperature, and the opening degree of the bypass valve 5. The data shown in FIG. 2 was measured under different conditions, and FIG. 4 shows the relationship between the incoming water temperature and the outside air temperature at which the COP is maximum and the opening degree of the bypass valve 5.

  The data of FIG. 3 measured in advance is stored in the heat exchange amount control means 29 in the form of an approximate expression or a matrix, for example, and the heat exchange amount control means 29 performs the processing shown in FIG.

  As shown in FIG. 4, the incoming water temperature detected by the incoming water temperature sensor 15 in STEP 60 and the outside air temperature detected by the outside air temperature sensor 31 are detected. In STEP 61, the incoming water temperature, the outside air temperature and the opening degree of the bypass valve 5 at which the COP is maximized are calculated. In STEP 62, the opening degree is determined so that the calculated opening degree of the bypass valve 5 is between a predetermined maximum value and a minimum value. In STEP63, the bypass valve 5 is operated.

  In this way, the heat exchange amount of the internal heat exchanger 8 is adjusted so that the COP of the refrigeration cycle unit 1 is optimized.

  On the other hand, the cold water at the bottom of the hot water storage tank 11 is conveyed to the hot water supply heat exchanger 3 by the boiling pump 10 and absorbs the heat of the refrigerant to become hot water, passes through the boiling pipe 13 and reaches the upper part of the hot water storage tank. Sent. At this time, the hot water is not mixed with water due to the density difference, and the hot water is stacked from the upper part of the hot water storage tank 11 so that the hot water is accumulated in the hot water storage tank 11. When the hot water storage temperature detection means 12a to 12d detects that the hot water storage tank 11 is filled with hot water, the refrigeration cycle unit 1 is stopped and heating is stopped.

  Moreover, since the hot water sent to the upper part of the hot water storage tank 11 through the boiling pipe 13 at the time of a boiling operation expand | swells when heated with the refrigerating cycle unit 1, the internal pressure in the hot water storage tank 11 rises. At this time, the pressure relief valve 14 is opened so as not to exceed the pressure resistance, and part of the hot water in the hot water storage tank 11 is drained to the outside through the drain pipe 26, and the internal pressure in the hot water storage tank 11 is reduced.

  When a user opens the hot water supply terminal 24 such as a faucet for hot water supply, hot water in the hot water storage tank 11 is first discharged from the hot water supply pipe 21 and supplied from the water supply pipe 19 to the hot water storage tank 11.

  Hot water is branched from the water supply bypass pipe 22 and mixed with hot water mixed with hot water heated by the hot water storage tank 11 and the heat exchanger 3 for hot water and low temperature water from the water supply at a mixing valve 23 at different mixing ratios. By doing so, the hot water supply temperature is changed and hot water is supplied to the hot water supply terminal 24. The mixing ratio at this time is controlled in accordance with the hot water temperature detected by the hot water temperature sensor 25 and is kept at a predetermined hot water temperature.

  In the present embodiment, the opening degree of the bypass valve 5 is determined based on the relationship between the incoming water temperature and the outside air temperature. However, instead of the incoming water temperature, an internal heat exchanger is provided from the outlet of the hot water supply heat exchanger 3. The same effect can be obtained by using the inlet temperature of 8 and the inlet refrigerant temperature of the air heat exchanger 6 instead of the outside air temperature.

  Furthermore, the opening degree of the bypass valve 5 may be determined by the incoming water temperature alone or the outside air temperature alone.

As described above, the heat pump water heater according to the present invention does not use a pressure sensor, but uses a temperature sensor to control the heat exchange amount of the internal heat exchanger, thereby controlling the heat pump in a less expensive manner. It is useful as an easily realized heat pump water heater.

Circuit diagram of heat pump water heater in Embodiment 1 of the present invention Relationship between opening of bypass valve and COP of heat pump water heater Relationship diagram of incoming water temperature, outside air temperature and bypass valve opening of the heat pump water heater Bypass valve control flowchart of the heat pump water heater Circuit diagram of conventional heat pump water heater Bypass valve control flowchart of the heat pump water heater

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Refrigeration cycle unit 2 Compressor 3 Heat exchanger for hot water supply 4 Decompression device 5 Bypass valve 6 Air heat exchanger 8 Internal heat exchanger 10 Boiling pump 11 Hot water storage tank 28 Bypass circuit 29 Heat exchange amount control means

Claims (3)

A refrigeration cycle unit configured by annularly connecting a compressor, a hot water supply heat exchanger, a decompression device, and an air heat exchanger; and a refrigerant from a refrigerant outlet side of the hot water heat exchanger to an inlet side of the decompression device; An internal heat exchanger for exchanging heat from the refrigerant outlet side of the air heat exchanger to the suction side of the compressor, and a bypass connecting the refrigerant outlet side of the hot water supply heat exchanger and the outlet side of the decompression device And a heat pump water heater that heats the water in the hot water storage tank and circulates the hot water in the hot water storage tank by circulating the water from the bottom of the hot water storage tank by a boiling pump to store hot water in the hot water storage tank. The heat exchange amount control means for controlling the heat exchange amount of the internal heat exchanger according to at least one of an incoming water temperature of the water flowing into the hot water supply heat exchanger and an outside air temperature is provided. Hi Toponpu water heater. The heat pump hot water supply according to claim 1, wherein a bypass valve is arranged in the bypass circuit, and the heat exchange amount control means controls the heat exchange amount of the internal heat exchanger by adjusting the opening degree of the bypass valve. Machine. The heat pump water heater according to claim 1 or 2, wherein a refrigerant used at a critical pressure or higher is used.

Images