JP2006234211A - Heat pump water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat pump water heater, wherein the discharge pressure of a compressor is less increased without worsening the coefficient of performance when the temperature of heated fluid is increased. <P>SOLUTION: The heat pump water heater comprises a heat pump unit which has the compressor 1, a high temperature refrigerant-water heat exchanger 2 for heat exchanging compressed heat medium with heated fluid, a pressure reducing device 3 for reducing the pressure of the heat medium on the downstream side of the high temperature refrigerant-water heat exchanger, and a refrigerant-air heat exchanger 5 for heat exchanging the heat medium on the downstream side of the pressure reducing device 3 with air are connected to one another in sequence. Herein, a low temperature refrigerant-water heat exchanger 4 is provided for heat exchanging the heated fluid with refrigerant on the downstream side of the pressure reducing device 3. When the temperature of the heated fluid entering into water in the high temperature refrigerant-water heat exchanger 2 is higher than a preset value, the heated fluid is heat exchanged with the low temperature refrigerant-water heat exchanger 4. Thus, the increased temperature of the heated fluid can be reduced to prevent the worsening of the coefficient of performance and an increase in the discharge pressure of the compressor 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat pump water heater having a hot water storage tank.

  Currently, there are many hot water heaters that use gas or electric heaters to heat water. However, in recent years, water heaters that use heat pumps are gradually becoming more common households in view of demands for higher energy utilization. It is becoming popular.

  FIG. 3 shows a configuration diagram of a conventional heat pump water heater. In the case of a heat pump water heater, the refrigerant heated to high temperature and high pressure by the compressor 1 is heat-exchanged with the water sent from the hot water storage tank 8 by the circulation pump 7 in the heat exchanger 2 for high temperature refrigerant to water. As a result, the water is heated to hot water, and at the same time, the refrigerant temperature decreases. The hot water is returned to the hot water storage tank 8 and stored in the hot water storage tank 8 until it is used. The refrigerant that has fallen in temperature changes to a low-temperature / low-pressure two-phase flow through the decompression device 3 and is sent to the refrigerant-to-air heat exchanger 5. In the refrigerant-to-air heat exchanger 5, the internal refrigerant evaporates and vaporizes by forcibly removing heat from the atmosphere by the blower fan 11. The vaporized refrigerant is sucked into the compressor 1 again and heated to high temperature and high pressure to heat the water again.

  As this operation is repeated, the hot water storage tank 8 is filled with sufficiently heated hot water. The hot water in the hot water storage tank 8 is mixed with tap water by a mixing valve (not shown) in order to take out hot water at a temperature set by a controller (not shown), and is used in a faucet or the like of each part at a predetermined temperature. .

Under normal conditions, the heat pump water heater can boil hot water with a coefficient of performance that exceeds that of gas and electric water heaters, and is attracting a great deal of attention from an energy-saving perspective. The coefficient of performance tends to get worse as the value rises, and the improvement of this point is an issue for the future. In order to improve this point, another method has been proposed for a method called a multi-function type having a floor heating function or the like (see, for example, Patent Document 1).
JP 2004-211986

  However, the deterioration of the coefficient of performance accompanying the rise in the temperature of the fluid to be heated has been a major issue for what is called a normal hot water supply type, which has been a bottleneck in improving the coefficient of performance throughout the year. In addition, if the boiling completion temperature is set low in order to pursue a coefficient of performance, fluid that cannot be used for hot water supply is stored in the lower part of the hot water storage tank, and the tank volume is not fully utilized.

  The present invention solves the above-mentioned conventional problems, prevents deterioration of the coefficient of performance due to the temperature rise of the fluid to be heated, and reduces the load on the cooling system by suppressing the increase in the discharge pressure of the compressor during the heating operation. An object is to provide a heat pump water heater.

In order to solve the conventional problems, a heat pump water heater of the present invention includes a compressor, a heat exchanger for high-temperature refrigerant that exchanges heat between a heat medium compressed by the compressor and a fluid to be heated, and the high temperature A heat pump unit comprising a pressure reducing device that depressurizes a heat medium downstream of a refrigerant-to-water heat exchanger, and a refrigerant-to-air heat exchanger that heat-exchanges heat between the heat medium downstream of the pressure reducing device and air. And a hot water unit connected to the high-temperature refrigerant-to-water heat exchanger and having the heated fluid, and heat exchange between the heated fluid and the refrigerant on the downstream side of the decompression device to exchange heat with the low-temperature refrigerant against water When the temperature of the heated fluid entering the high-temperature refrigerant / water heat exchanger is higher than a predetermined value, the heated fluid exchanges heat with the low-temperature refrigerant / water heat exchanger. The structure of the fluid to be heated If degrees rises is to prevent deterioration of the coefficient of performance by performing heat is cooled by the low temperature refrigerant to water heat exchanger.

  ADVANTAGE OF THE INVENTION According to this invention, the deterioration of a coefficient of performance by the temperature rise of a to-be-heated fluid can be prevented, and the heat pump water heater which reduced the load of the cooling system by suppressing the discharge pressure rise of the compressor at the time of heating operation can be provided.

  The first invention is a compressor, a heat exchanger for high-temperature refrigerant to water that exchanges heat between the heat medium compressed by the compressor and the fluid to be heated, and heat on the downstream side of the heat exchanger for high-temperature refrigerant to water. A decompression device that decompresses the medium, a heat pump unit in which a heat exchanger for air to air that exchanges heat between the heat medium downstream of the decompression device and air, and a heat exchanger for high temperature refrigerant to water are connected to the heat exchanger A low-temperature refrigerant-to-water heat exchanger for exchanging heat between the heated fluid and a refrigerant on the downstream side of the decompression device. When the temperature of the heated fluid that enters the heat exchanger is higher than a predetermined value, the heated fluid is configured to exchange heat with the low-temperature refrigerant-to-water heat exchanger. The temperature of the It is possible to prevent an increase of the discharge pressure of the compressor.

  The second invention is a compressor, a heat exchanger for high-temperature refrigerant to water that exchanges heat between the heat medium compressed by the compressor and the fluid to be heated, and heat downstream of the heat exchanger for high-temperature refrigerant and water. A decompression device that decompresses the medium, a heat pump unit in which a heat exchanger for air to air that exchanges heat between the heat medium downstream of the decompression device and air, and a heat exchanger for high temperature refrigerant to water are connected to the heat exchanger A low-temperature refrigerant-to-water heat exchanger for exchanging heat between the heated fluid and a refrigerant on the downstream side of the decompression device. When the evaporating temperature of the refrigerant in the exchanger is lower than a predetermined value, the heated fluid is configured to exchange heat with the low-temperature refrigerant-to-water heat exchanger, and the refrigerant-to-air heat exchanger is frosted. When the evaporation temperature drops to the area where Not from the atmosphere, by heat exchange from the heated fluid, it is possible to prevent deterioration of the coefficient of performance.

  The third invention is the heat pump water heater of the first invention or the second invention, in particular, comprising a hot water storage means for storing the heated fluid in the hot water unit, and the refrigerant in the low temperature refrigerant to water heat exchanger. The fluid to be heated after heat exchange is configured to flow from the upper part of the hot water storage means after being heated in a heat exchanger for high-temperature refrigerant to water. A heat pump water heater that can be secured and is easy to use can be provided.

  In a fourth aspect of the invention, in particular, in the heat pump water heater of the first or second aspect of the invention, a water temperature detecting means is provided on the channel outlet side of the fluid to be heated of the heat exchanger for low-temperature refrigerant versus water, and the detected temperature When is higher than a predetermined value, the heating operation is stopped, so that the deterioration of the coefficient of performance and the increase in the discharge pressure of the compressor can be prevented.

  In the fifth aspect of the invention, in particular, by using carbon dioxide as the refrigerant of the heat pump water heater of the first to fourth aspects, it is possible to realize a high-temperature and high-efficiency hot water storage operation and global environmental conservation.

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 configuration diagram of a heat pump water heater in Embodiment 1 of the present invention. In addition, the refrigerant used in the heat pump water heater of the present invention may be a fluorocarbon refrigerant such as R22 which has been widely used in the past. The carbon dioxide refrigerant, which is a natural refrigerant, can obtain a greater effect. In the following, carbon dioxide is used as the refrigerant, but other refrigerants may be used.

  The heat pump water heater is a refrigerant comprising a compressor 1, a high-temperature refrigerant-to-water heat exchanger 2, a decompression device 3, a low-temperature refrigerant-to-water heat exchanger 4, a refrigerant-to-air heat exchanger 5, and electromagnetic valves 6a and 6b. It comprises a circulation circuit A and a hot water supply circuit B to which the high temperature refrigerant / water heat exchanger 2, a low temperature refrigerant / water heat exchanger 4, a circulation pump 7, a hot water storage tank 8, a three-way valve 9, and a check valve 10 are connected. The compressor 1, the heat exchanger 2 for refrigerant / water, the decompressor 3, the heat exchanger 4 for low temperature refrigerant / water, the heat exchanger 5 for refrigerant / air, the electromagnetic valves 6a, 6b, the blower fan 11, etc. are heat pumps. Contained in the unit. The circulating pump 7, hot water storage tank 8, three-way valve 9, check valve 10, control means (not shown) and the like are accommodated in a hot water unit.

  The incoming water temperature detecting means 12 is installed at the inlet of the three-way valve 9 and detects the incoming water temperature supplied from the hot water storage tank 8. The outlet water temperature detection means 13 is installed at the water-side outlet of the low-temperature refrigerant-to-water heat exchanger 4 and detects the outlet water temperature cooled by the heat pump water heater. The hot water temperature detection means 14 is installed at the water-side outlet of the high-temperature refrigerant-to-water heat exchanger 2 and detects the temperature of the hot water heated by the heat pump water heater. The control means controls the operating frequency of the compressor 1 and opens the decompression device 3 so that the temperature set by a controller (not shown) installed in the room is equal to the temperature detected by the tapping temperature detection means 14. The rotational speed of the circulation pump 7 and the rotational speed of the blower fan 11 are controlled.

  The operation of the heat pump water heater will be described. After the operation is started, the circulation pump 7 is operated for a predetermined time in order to detect the temperature of the water supplied from the lower part of the hot water storage tank 8. Here, when the incoming water temperature detecting means 12 detects a temperature lower than a predetermined temperature (for example, 25 ° C.), the three-way valve 9 switches to a route for directly sending water to the high-temperature refrigerant-to-water heat exchanger 2, and the circulation pump 7 through which water is sent to the high-temperature refrigerant-to-water heat exchanger 2 and heat-exchanged with the high-temperature refrigerant-to-water heat exchanger 2 into which the high-temperature and high-pressure superheated gas refrigerant discharged from the compressor 1 flows. Heat the water with. Hot water heated to a predetermined temperature is returned to the upper part of the hot water storage tank 8 and stored.

  Since the carbon dioxide refrigerant does not have a condensing region and is heat-exchanged in the supercritical region, the refrigerant temperature gradually decreases in the high-temperature refrigerant-to-water heat exchanger 2 and is decompressed by the decompression device 3. Since the water in the hot water storage tank 8 is directly sent to the high-temperature refrigerant-to-water heat exchanger 2, the solenoid valve 6a is closed, the solenoid valve 6b is opened, and the refrigerant is sent to the refrigerant-to-air heat exchanger 5. . In the refrigerant-to-air heat exchanger 5, the refrigerant is vaporized by forcibly removing heat from the atmosphere by the blower fan 11, and returns to the compressor 1.

When the above operation is repeated, the low temperature water in the hot water storage tank 8 is replaced with high temperature hot water, and the temperature detected by the incoming water temperature detecting means 12 gradually increases. In this process, when the incoming water temperature detecting means 12 detects a temperature (for example, 25 ° C.) higher than a predetermined temperature, the three-way valve 9 is switched, and water is sent to the low-temperature refrigerant-to-water heat exchanger 4. At the same time, the electromagnetic valve 6 a is opened and the electromagnetic valve 6 b is closed, and the low-temperature refrigerant decompressed by the decompression device 3 is sent to the low-temperature refrigerant-to-water heat exchanger 4. Here, the water and the refrigerant are subjected to heat exchange, and the water temperature is lowered and sent to the high-temperature refrigerant-to-water heat exchanger 2 to exchange heat with the high-temperature and high-pressure superheated gas refrigerant to heat the water to a predetermined temperature. The hot water storage tank 8 is returned and stored.

  Further, when the above operation is repeated, the temperature detected by the incoming water temperature detecting means 12 also rises, the cooling at the low temperature refrigerant-to-water heat exchanger 4 cannot catch up, and the temperature detected by the outlet water temperature detecting means 13 also increases. . Here, when the outlet water temperature detection means 13 detects a predetermined temperature (for example, 25 ° C.), it is determined that the hot water storage tank 8 is filled with hot water, the compressor 1 is stopped, and the heating operation is terminated.

  By performing the operation as described above, the water temperature supplied to the high-temperature refrigerant-to-water heat exchanger 2 can be suppressed to a certain temperature or less, and the deterioration of the coefficient of performance and the increase in the discharge pressure of the compressor can be suppressed. be able to.

  Note that the various materials and numerical values shown in this embodiment are not necessarily limited to these, and there is no problem with other materials and numerical values as long as they can play a predetermined role.

(Embodiment 2)
FIG. 2 is a configuration diagram of a heat pump water heater in Embodiment 2 of the present invention. The structure of the heat pump water heater is implemented except that an evaporating temperature detecting means 15 is added to the outlet of the refrigerant-to-air heat exchanger 5 and a flow rate adjusting valve 16 is added to the water-side inlet of the high-temperature refrigerant-to-water heat exchanger 2. This is the same as the first embodiment.

  The operation of the heat pump water heater will be described. The three-way valve 9 switches to a route for sending water directly to the high-temperature refrigerant-to-water heat exchanger 2, and the flow control valve 16 adjusts so that all water is sent to the high-temperature refrigerant-to-water heat exchanger 2, and the circulation pump 7 Through, the water is sent to the high temperature refrigerant to water heat exchanger 2. In the high-temperature refrigerant-to-water heat exchanger 2, heat is exchanged between the high-temperature and high-pressure superheated gas refrigerant discharged from the compressor 1 and water. Hot water heated to a predetermined temperature is returned to the hot water storage tank 8 and stored.

  Since the carbon dioxide refrigerant does not have a condensing region and is heat-exchanged in the supercritical region, the refrigerant temperature gradually decreases in the high-temperature refrigerant-to-water heat exchanger 2 and is decompressed by the decompression device 3. Since the water in the hot water storage tank 8 is directly sent to the high-temperature refrigerant-to-water heat exchanger 2, the solenoid valve 6a is closed, the solenoid valve 6b is opened, and the refrigerant is sent to the refrigerant-to-air heat exchanger 5. . In the refrigerant-to-air heat exchanger 5, the refrigerant is vaporized by forcibly removing heat from the atmosphere by the blower fan 11, and returns to the compressor 1.

  Here, when a decrease in the outside air temperature, a change in the hot water temperature, or the like occurs, the evaporating temperature in the refrigerant-to-air heat exchanger 5 decreases, and the operation is performed in a state below a predetermined temperature (for example, −3 ° C.). There is. If the operation is performed for a long time in a state where the evaporation temperature is low, the refrigerant-to-air heat exchanger 5 is frosted, so that the heat exchange performance is lowered and the defrosting operation is required, leading to deterioration in the coefficient of performance.

  For this reason, when the evaporating temperature detecting means 15 attached to the outlet of the refrigerant-to-air heat exchanger 5 detects a predetermined temperature (for example, −3 ° C.), the three-way valve 9 is connected to the low-temperature refrigerant-to-water heat exchanger 4. At the same time, the solenoid valve 6a is opened, the solenoid valve 6b is closed, the refrigerant-to-air heat exchanger 5 is not used, and the refrigerant is evaporated by using the low-temperature refrigerant-to-water heat exchanger 4. Turn into. If the outlet temperature of the water is too low, there is a risk of freezing. Therefore, the amount of circulation of the circulation pump 7 is adjusted by the control means so that the outlet temperature detection means 13 does not fall below a predetermined temperature (for example, 3 ° C.).

Also, the heat-exchanged water is sent to the high-temperature refrigerant-to-water heat exchanger 2 and heated by exchanging heat with the high-temperature refrigerant. Is returned to the lower part of the hot water storage tank 8 to enable the hot water temperature detection means 14 to maintain a predetermined temperature (for example, 90 ° C.).

  By performing the operation as described so far, the defrosting operation becomes unnecessary even at a low outside temperature, and the deterioration of the coefficient of performance can be suppressed.

  In this embodiment, the refrigerant evaporation temperature is detected at the refrigerant-to-air heat exchanger outlet, but may be detected at the inlet side if there is no problem. Note that the various materials and numerical values shown in this embodiment are not necessarily limited to these, and there is no problem with other materials and numerical values as long as they can play a predetermined role.

  As described above, the heat pump water heater according to the present invention can be applied to a water-cooled air conditioner and the like because it can reduce the load on the high temperature side by using the low temperature side exhaust heat of the cooling system.

Configuration diagram of heat pump water heater in Embodiment 1 of the present invention The block diagram of the heat pump water heater in Embodiment 2 of this invention Configuration diagram of conventional heat pump water heater

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 Heat exchanger for high temperature refrigerant | coolant versus water 3 Pressure reducing device 4 Heat exchanger for low temperature refrigerant | coolant versus water 5 Heat exchanger for refrigerant | coolant versus air 8 Hot water storage tank 13 Outlet temperature detection means

Claims (5)

A compressor, a heat exchanger for high-temperature refrigerant to water that exchanges heat between the heat medium compressed by the compressor and the fluid to be heated, and a decompression device that depressurizes the heat medium downstream of the heat exchanger for high-temperature refrigerant to water A heat pump unit formed by sequentially connecting a refrigerant-to-air heat exchanger for exchanging heat between the heat medium and air downstream of the decompression device, and connected to the high-temperature refrigerant-to-water heat exchanger, A low-temperature refrigerant-to-water heat exchanger that exchanges heat between the heated fluid and a refrigerant downstream of the decompression device, and enters the high-temperature refrigerant-to-water heat exchanger. When the temperature of the fluid to be heated is higher than a predetermined value, the heat pump water heater is configured such that the fluid to be heated exchanges heat with the heat exchanger for low-temperature refrigerant versus water. A compressor, a heat exchanger for high-temperature refrigerant to water that exchanges heat between the heat medium compressed by the compressor and the fluid to be heated, and a decompression device that depressurizes the heat medium downstream of the heat exchanger for high-temperature refrigerant to water A heat pump unit formed by sequentially connecting a refrigerant-to-air heat exchanger for exchanging heat between the heat medium and air downstream of the decompression device, and connected to the high-temperature refrigerant-to-water heat exchanger, A low-temperature refrigerant-to-water heat exchanger that exchanges heat with the fluid to be heated and a refrigerant on the downstream side of the decompression device, and evaporating the refrigerant in the refrigerant-to-air heat exchanger When the temperature is lower than a predetermined value, the heat pump water heater is configured such that the heated fluid exchanges heat with the low-temperature refrigerant-to-water heat exchanger. The hot water unit is provided with hot water storage means for storing the heated fluid, and the heated fluid after heat exchange with the refrigerant in the low-temperature refrigerant-to-water heat exchanger is heated in the high-temperature refrigerant-to-water heat exchanger, The heat pump water heater according to claim 1, wherein the heat pump water heater is configured to flow from an upper portion of the hot water storage means. The heat pump hot water supply according to claim 3, wherein a water temperature detecting means is provided on the outlet side of the fluid to be heated of the heat exchanger for low-temperature refrigerant to water, and the heating operation is stopped when the detected temperature is higher than a predetermined value. Machine. The heat pump water heater according to any one of claims 1 to 4, wherein the refrigerant is carbon dioxide.

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