JP4124164B2 - Heat pump water heater - Google Patents

Description

  The present invention relates to a hot water storage type heat pump hot water supply apparatus.

  Conventionally, this type of heat pump hot water supply apparatus is shown in FIG. FIG. 3 is a configuration diagram of a conventional heat pump water heater. In FIG. 3, a refrigerant circulation circuit comprising a compressor 1, a hot water supply heat exchanger 2, an expansion device 3 and an evaporator 4, a hot water storage tank 5, a circulation pump 6, the hot water supply heat exchanger 2 and an auxiliary heater 19 are provided. The high-temperature and high-pressure superheated gas refrigerant discharged from the compressor 1 flows into the hot water supply heat exchanger 2 and heats the hot water supplied from the circulation pump 6.

The condensed and liquefied refrigerant is decompressed by the expansion device 3 and flows into the evaporator 4, where it absorbs atmospheric heat to evaporate and returns to the compressor 1. On the other hand, the hot water heated by the hot water supply heat exchanger 2 flows into the upper part of the hot water storage tank 5 and is gradually stored from above. When the inlet water temperature of the hot water supply heat exchanger 2 reaches a set value, the water temperature detector 20 detects it, stops the heat pump operation by the compressor 1, and switches to the independent operation of the auxiliary heater 19. Yes (for example, see Patent Document 1).
JP 60-165157 A

  However, in the conventional configuration as described above, a hot water mixed layer is formed at the portion where the hot water in the hot water tank 5 is in contact with water as the boiling operation time elapses, and the layer gradually expands. This occurs due to heat conduction and convection in high temperature hot water and low temperature water. Heat is transferred from the high temperature hot water to the low temperature water, and the temperature of the high temperature hot water decreases at the boundary portion, while the temperature of the low temperature water increases. Accordingly, when the boiling operation is almost completed, the temperature of the water flowing into the hot water supply heat exchanger 2 becomes high, so that the discharge pressure and the discharge temperature of the compressor 1 rise, and the winding of the motor of the compressor 1 The durability of the compressor 1 such as a rise in temperature becomes a problem. Therefore, since the operation was stopped in a state where the temperature of the water flowing into the hot water supply heat exchanger was low, the operation was stopped with the lower part of the hot water tank 5 being in a state of low temperature water, and the hot water in the hot water tank 5 was The capacity could not be used effectively, so the amount of hot water stored was decreasing.

In addition, in order to increase the amount of stored hot water, after stopping the heat pump operation, when the amount of stored hot water is increased by the independent operation of the auxiliary heater 19, heating is performed by an electric heater, so that power consumption increases and efficiency decreases. It was.

  Further, in the conventional configuration as described above, there is no means for effectively using the amount of heat of the outside air even when the outside air temperature is higher than the water temperature, and the power consumption is relatively low even when the outside air temperature is high and the water temperature is low. It was high.

  The present invention solves the above-described conventional problems, and an object thereof is to provide a heat pump hot water supply apparatus that can be operated safely and with high efficiency by reducing the discharge pressure of the compressor.

In order to solve the above-described conventional problems, a heat pump hot water supply apparatus of the present invention includes at least a compressor, a heat exchanger for hot water supply, a first expansion device, a first evaporator, a second expansion device, and a second evaporation. A refrigerant circuit in which the heaters are sequentially connected, at least a hot water storage tank, a hot water supply circuit to which the hot water supply heat exchanger is connected, an incoming water temperature sensor for detecting the temperature of hot water flowing into the hot water supply heat exchanger, and the hot water supply A hot water temperature sensor for detecting the temperature of hot water flowing out of the heat exchanger, a control device for controlling the opening degree of the first throttling device and the second throttling device, and the first throttling device and the The second throttle device can control the flow rate by changing the throttle opening, and the control device can detect the temperature of the hot water detected by the hot water temperature sensor and the temperature of the hot water detected by the hot water temperature sensor. When is over the set value Operating the opening of the first throttle device in the opening direction, the opening degree of the second throttle device characterized in that control to operate in the closing direction, raised become close operation completion boiling When the incoming water temperature rises, the first throttling device is operated in the opening direction, the second throttling device is operated in the closing direction, and the refrigerant pressure flowing into the first evaporator is increased. Thus, the first evaporator can act as a radiator and can exchange heat with the outside air and the second evaporator, and the discharge pressure of the compressor of the refrigerant circuit can be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the discharge pressure of a compressor can be reduced and the heat pump hot-water supply apparatus which can be drive | operated safely and highly efficiently can be provided.

The first invention includes at least a compressor, a hot water heat exchanger, a first throttle device, a first evaporator, a second throttle device, a refrigerant circuit in which the second evaporator is sequentially connected, and at least a hot water storage tank A hot water supply circuit connected to the hot water heat exchanger, an incoming water temperature sensor for detecting the temperature of hot water flowing into the hot water heat exchanger, and a temperature of hot water flowing out of the hot water heat exchanger And a controller for controlling the opening of the first and second throttle devices, the first and second throttle devices varying the throttle opening. The flow rate can be controlled, and the control device is configured such that when the incoming water temperature detected by the incoming water temperature sensor is equal to or higher than a predetermined value and the outgoing hot water temperature detected by the outgoing hot water temperature sensor is higher than a set value, Operate the opening of the expansion device in the opening direction, The opening of the second throttle device characterized in that control to operate in the closing direction, when the incoming water temperature becomes close operation completed boiling becomes higher, the first throttle device opening direction And the second expansion device is operated in the closing direction to increase the pressure of the refrigerant flowing into the first evaporator, so that the first evaporator acts as a radiator, and the outside air and the second It is possible to exchange heat with the evaporator, and it is possible to reduce the discharge pressure of the compressor of the refrigerant circuit.

  In addition, even when the incoming water temperature rises near the completion of the boiling operation, the first evaporator can act as a radiator, so that the discharge pressure and discharge temperature of the compressor in the refrigerant circuit are reduced. However, the hot water can be easily heated to a high temperature, and the heat pump can be operated safely and with high efficiency. Moreover, hot water can be stored up to the bottom of the hot water tank, and the capacity of the hot water tank can be used effectively.

Moreover, the discharge pressure and discharge temperature of the compressor of the refrigerant circuit can be reduced without increasing the number of parts.

Further, when the incoming water temperature is low, the first evaporator acts as an evaporator, so that a large amount of heat absorption can be obtained, and the heat pump can be operated with high efficiency.

In addition, even when the temperature of the hot water is high, the refrigerant pressure flowing into the first evaporator is made high so that the first evaporator acts as a radiator and heat is exchanged with the outside air and the second evaporator. The discharge pressure of the compressor of the refrigerant circuit can be reduced, and the heat pump can be operated safely and with high efficiency.

The second invention, the outside air temperature sensor for detecting the outside air temperature is provided, wherein the control device includes a water inlet temperature detected by the entering water temperature sensor, a hot water temperature detected by the hot water temperature sensor, the outside air temperature sensor And controlling the opening degree of the first throttle device in the opening direction and controlling the opening degree of the second throttle device in the closing direction based on the outside air temperature detected in step (b). The first evaporator is operated in the opening direction, the second throttle apparatus is operated in the closing direction, and the pressure of the refrigerant flowing into the first evaporator is increased, whereby the first evaporator Can act as a radiator and exchange heat with the outside air and the second evaporator, the discharge pressure of the compressor of the refrigerant circuit can be reduced, and the heat pump can be operated with higher efficiency.

According to a third aspect of the present invention, a bypass circuit via a two-way valve that bypasses the first throttle device is provided in the refrigerant circuit, and the second throttle device can control the flow rate by varying the throttle opening. Therefore, the discharge pressure of the compressor of the refrigerant circuit can be reduced at low cost, and hot water can be heated to a higher temperature safely and efficiently, and the amount of stored hot water can be increased.

A fourth invention, prior Symbol control apparatus, when the incoming water temperature detected by the entering water temperature sensor is a predetermined value or more, the two-way valve of the bypass circuit is operated in the opening direction, the second throttle device The opening of the valve is controlled to operate in the closing direction. When the incoming water temperature detected by the incoming water temperature sensor is equal to or higher than a set value, the two-way valve is operated in the opening direction, Since the opening degree of the expansion device is controlled so as to operate in the closing direction, when the incoming water temperature is low, the first evaporator acts as an evaporator, so that a large amount of heat absorption can be obtained at low cost. The heat pump can be operated with high efficiency.

A fifth invention is, before Symbol controller in the incoming water temperature detected by the incoming water temperature sensor is more than a predetermined value, and when the hot water temperature is above a predetermined value detected by the hot water temperature sensor, the bypass circuit The two-way valve is operated in the opening direction, and the opening of the second throttle device is controlled to operate in the closing direction. The incoming water temperature detected by the incoming water temperature sensor is equal to or higher than a set value. And when the hot-water temperature detected by the hot-water temperature sensor is equal to or higher than a set value, the two-way valve of the bypass circuit is operated in the opening direction, and the opening degree of the second expansion device is controlled in the closing direction. Therefore, by setting the refrigerant pressure flowing into the first evaporator to a high pressure, the first evaporator can act as a radiator, and heat can be exchanged with the outside air and the second evaporator. Reduce the discharge pressure of the machine. Can be can be operated safely high efficiency heat pump at a low cost.

A sixth invention is the outdoor air temperature sensor for detecting the outside air temperature is provided, wherein the control device includes a water inlet temperature detected by the entering water temperature sensor, a hot water temperature detected by the hot water temperature sensor, the outside air temperature sensor The two-way valve of the bypass circuit is operated in the opening direction based on the outside air temperature detected in step 1, and the opening of the second expansion device is controlled to operate in the closing direction. Since the two-way valve of the bypass circuit is operated in the opening direction and the opening of the second expansion device is controlled to operate in the closing direction, the refrigerant pressure flowing into the first evaporator is set to a high pressure. The first evaporator can act as a radiator to exchange heat with the outside air and the second evaporator, the discharge pressure of the compressor of the refrigerant circuit can be reduced, and the heat pump can be safely made at low cost Driving with high efficiency It is possible.

Since the seventh invention uses carbon dioxide gas as the refrigerant in the refrigerant circuit, it achieves high temperature of the hot water supply with high efficiency, and even if the refrigerant leaks to the outside, the influence on global warming is extremely high Less.

  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.

  In addition, in each Example, the same code | symbol is provided about the part which has the same structure and the same operation | movement, and detailed description is abbreviate | omitted.

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

  In FIG. 1, a compressor 31, a hot water supply heat exchanger 32, a first expansion device 33, a first evaporator 34, a second expansion device 35, and a second evaporator 36 are sequentially connected in an annular shape to form a refrigerant. A carbon dioxide gas is enclosed to form a refrigerant circulation circuit, and the first evaporator 34 and the second evaporator 36 are integrally formed and include a fan 39 for blowing outside air. Further, a hot water supply circuit is formed in which a hot water storage tank 41, a circulation pump 42, and a hot water supply heat exchanger 32 are connected in order, and the high-temperature and high-pressure superheated gas refrigerant discharged from the compressor 31 flows into the hot water supply heat exchanger 32. Here, the hot water supplied from the circulation pump 42 is heated.

  Also, an incoming water temperature sensor 51 for detecting the incoming water temperature flowing into the hot water supply heat exchanger 32, a hot water temperature sensor 52 for detecting the outgoing water temperature flowing out from the hot water heat exchanger 32, and an outside air temperature sensor 53 for detecting the outside air temperature are provided. A control device 54 is provided for controlling the opening and closing of the first throttling device 33 and the second throttling device 35 in comparison with a preset temperature.

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

  During normal operation, the opening of the second expansion device is fully opened, and the first evaporator 34 and the second evaporator 36 function as an evaporator. At this time, the refrigerant (carbon dioxide gas) compressed to a supercritical state of high temperature and high pressure by the compressor 31 exchanges heat with water flowing through the hot water supply circuit in the hot water supply heat exchanger 32, and becomes a medium temperature and high pressure refrigerant. After the pressure is reduced by the first expansion device 33, it flows into the first evaporator 34 and the second evaporator 36, where it exchanges heat with the outside air blown by the fan 39 to evaporate and convert it into the compressor 1. Return. On the other hand, the hot water sent by the circulation pump 42 is heated by the hot water heat exchanger 32, and the generated hot water flows into the upper part of the hot water storage tank 41 and is gradually stored from above.

  On the other hand, as the boiling operation time elapses, a hot water mixed layer is formed at a portion where the hot water in the hot water storage tank 41 comes into contact with water, and the layer expands to the lower part of the hot water storage tank 41. The temperature of water flowing into the hot water supply heat exchanger 32 from the lower part through the circulation pump 42 becomes higher.

  In this case, in the hot water supply heat exchanger 32, the refrigerant only dissipates heat up to the inflowing water temperature, so the density of the refrigerant at the outlet of the hot water supply heat exchanger 32 is low and the high pressure increases. At this time, when the incoming water temperature detected by the incoming water temperature sensor 51 rises above the temperature preset in the control device 54, the first throttle device 33 is operated in the opening direction, and the second throttle device 35 is closed. To work. In this way, by setting the refrigerant pressure flowing into the first evaporator 34 to a high pressure, the first evaporator 34 acts as a radiator and exchanges heat with the outside air to become a medium-temperature and high-pressure refrigerant. After being reduced in pressure by the expansion device 35 and becoming a low-temperature and low-pressure refrigerant, it flows into the second evaporator 36, exchanges heat with the outside air, evaporates, and returns to the compressor 1.

  At this time, since the first evaporator 34 acts as a radiator, among the refrigerant sealed in the refrigerant circuit, the place where the high-pressure refrigerant can exist becomes the hot water supply heat exchanger 32 and the first evaporator 34 and the volume is increased. In addition, since the refrigerant is radiated by the outside air in the first evaporator 34, a high-density refrigerant exists in the first evaporator.

  As a result, the discharge pressure of the compressor 31 of the refrigerant circuit can be reduced, and the heat pump water heater can be operated safely and with high efficiency. Moreover, hot water can be stored up to the lower part of the hot water tank 41, and the capacity of the hot water tank 41 can be effectively used. Moreover, when the hot water temperature is high, it is necessary to increase the discharge temperature of the compressor 31 of the refrigerant circuit. For this purpose, it is also necessary to increase the discharge pressure of the compressor 31. Therefore, when the incoming water temperature rises, the discharge pressure of the compressor 31 increases as the hot water temperature increases.

  Accordingly, when the incoming water temperature detected by the incoming water temperature sensor 51 and the outgoing hot water temperature detected by the outgoing hot water temperature sensor 52 rise above the temperature preset in the control device 54, the first throttle device 33 is operated in the opening direction. Then, the second expansion device 35 is operated in the closing direction, the refrigerant pressure flowing into the first evaporator 34 is set to a high pressure, and the first evaporator 34 is operated as a radiator, whereby the compressor of the refrigerant circuit The discharge pressure of 31 can be reduced, and the heat pump water heater can be operated more safely and efficiently.

  Further, when the outside air temperature is high, the evaporation pressure increases. The higher the evaporation pressure, the smaller the specific volume of the refrigerant sucked in the compressor 31, the refrigerant circulation amount increases, and the hot water supply capacity increases. Therefore, the discharge pressure of the compressor 31 increases as the outside air temperature increases.

  Thus, the discharge pressure of the compressor 31 tends to increase as the hot water temperature and the outside air temperature are higher and the incoming water temperature is higher.

  Therefore, the first throttling device 33 is operated in the opening direction by the incoming water temperature detected by the incoming water temperature sensor 51, the outgoing hot water temperature detected by the outgoing hot water temperature sensor 52, and the outside air temperature detected by the outdoor air temperature sensor 53, and the second By operating the expansion device 35 in the closing direction, the refrigerant pressure flowing into the first evaporator 34 is set to a high pressure, and the first evaporator 34 is operated as a radiator, whereby the discharge pressure of the compressor 31 of the refrigerant circuit is reduced. The heat pump water heater can be operated more safely and efficiently.

  Further, when the first evaporator 34 and the second evaporator 36 are frosted by the operation at a low outside air temperature, the first evaporator 34 is provided below the second evaporator 36, When the evaporator 34 acts as a radiator, the heat exchanger can be prevented from freezing.

(Embodiment 2)
FIG. 2 shows a configuration diagram of a heat pump water heater in the second embodiment of the present invention.

  In FIG. 2, the same elements as those in FIG. Here, what is different from FIG. 1 is that a bypass circuit 38 via a two-way valve 37 and a control device 54 for controlling the opening and closing of the two-way valve 37 are provided in parallel with the first throttle device.

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

  The refrigerant (carbon dioxide gas) compressed in the supercritical state of high temperature and high pressure by the compressor 31 exchanges heat with the water flowing through the hot water supply circuit in the hot water supply heat exchanger 32 and becomes itself a medium temperature and high pressure refrigerant. After being depressurized by the device 33, it flows into the first evaporator 34, where it exchanges heat with the outside air blown by the fan 39 to evaporate and return to the compressor 31. On the other hand, the hot water sent by the circulation pump 42 is heated by the hot water heat exchanger 32, and the generated hot water flows into the upper part of the hot water storage tank 41 and is gradually stored from above.

  On the other hand, as the boiling operation time elapses, a hot water mixed layer is formed at a portion where the hot water in the hot water storage tank 41 comes into contact with water, and the layer expands to the lower part of the hot water storage tank 41. The temperature of water flowing into the hot water supply heat exchanger 32 from the lower part through the circulation pump 42 becomes higher.

  In this case, when the incoming water temperature detected by the incoming water temperature sensor 51 rises above the temperature preset in the control device 54, the two-way valve 37 of the bypass circuit 38 is operated in the opening direction, and the second throttle The opening of the device is operated in the closing direction. In this way, by setting the refrigerant pressure flowing into the first evaporator 34 to a high pressure, the first evaporator 34 acts as a radiator and exchanges heat with the outside air to become a medium-temperature and high-pressure refrigerant. After being reduced in pressure by the expansion device 35 and becoming a low-temperature and low-pressure refrigerant, it flows into the second evaporator 36, exchanges heat with the outside air, evaporates, and returns to the compressor 1.

  At this time, since the first evaporator 34 acts as a radiator, among the refrigerant sealed in the refrigerant circuit, the place where the high-pressure refrigerant can exist becomes the hot water supply heat exchanger 32 and the first evaporator 34 and the volume is increased. In addition, since the refrigerant is radiated by the outside air in the first evaporator 34, a high-density refrigerant exists in the first evaporator.

  As a result, the discharge pressure of the compressor 31 of the refrigerant circuit can be reduced, and the heat pump water heater can be operated safely and with high efficiency.

  Further, when the first evaporator 34 and the second evaporator 36 are frosted by the operation at a low outside air temperature, the first evaporator 34 is provided below the second evaporator 36, When the evaporator 34 acts as a radiator, the heat exchanger can be prevented from freezing.

  As described above, the heat pump hot water supply apparatus according to the present invention can easily heat the hot water supply to a high temperature while reducing the discharge pressure and discharge temperature of the compressor of the refrigerant circuit. It can also be applied to uses such as a heat pump water heater to be obtained and an air conditioner to obtain high temperature air.

The block diagram of the heat pump hot-water supply apparatus in Embodiment 1 of this invention The block diagram of the heat pump hot-water supply apparatus in Embodiment 2 of this invention Configuration diagram of conventional heat pump water heater

Explanation of symbols

DESCRIPTION OF SYMBOLS 31 Compressor 32 Hot water supply heat exchanger 33 1st expansion device 34 1st evaporator 35 2nd expansion device 36 2nd evaporator 37 Two-way valve 38 Bypass circuit 39 Fan 41 Hot water storage tank 42 Circulation pump 51 Incoming water Temperature sensor 52 Hot water temperature sensor 53 Outside air temperature sensor 54 Control device

Claims (7)

A refrigerant circuit in which at least a compressor, a hot water supply heat exchanger, a first expansion device, a first evaporator, a second expansion device, and a second evaporator are sequentially connected, at least a hot water storage tank, and the hot water supply heat exchange A hot water supply circuit connected to a hot water supply device, an incoming water temperature sensor for detecting the temperature of hot water flowing into the hot water supply heat exchanger, a hot water temperature sensor for detecting the temperature of hot water flowing out of the hot water supply heat exchanger, A control device for controlling the opening of the first throttling device and the second throttling device; the first throttling device and the second throttling device can control the flow rate by varying the throttling opening; When the incoming water temperature detected by the incoming water temperature sensor is equal to or higher than a predetermined value and the outgoing hot water temperature detected by the outgoing hot water temperature sensor is equal to or higher than a set value, the control device controls the opening degree of the first throttle device. Operating in the opening direction, the second diaphragm device The heat pump water heater, characterized in that for controlling the opening so as to operate in the closing direction. An outside air temperature sensor for detecting an outside air temperature is provided , and the control device converts the incoming water temperature detected by the incoming water temperature sensor, the outgoing hot water temperature detected by the outgoing hot water temperature sensor, and the outdoor air temperature detected by the outdoor air temperature sensor. 2. The heat pump hot water supply according to claim 1 , wherein the opening of the first expansion device is controlled to operate in the opening direction and the opening of the second expansion device is controlled to operate in the closing direction. apparatus. The heat pump hot water supply apparatus according to claim 1 or 2, wherein a bypass circuit via a two-way valve that bypasses the first throttling device is provided in the refrigerant circuit. The control device operates the two-way valve of the bypass circuit in the opening direction when the incoming water temperature detected by the incoming water temperature sensor is equal to or higher than a predetermined value, and sets the opening of the second throttling device in the closing direction. The heat pump hot water supply apparatus according to claim 3 , wherein the heat pump hot water supply apparatus is controlled to operate. Wherein the control device, at a water inlet temperature detected by the incoming water temperature sensor is more than a predetermined value, and, when hot water temperature detected by the hot water temperature sensor is a predetermined value or more, the two-way valve of the bypass circuit in the opening direction The heat pump hot water supply apparatus according to claim 3 , wherein the heat pump hot water supply apparatus is operated and controlled so that the opening degree of the second expansion device is operated in a closing direction. An outside air temperature sensor for detecting an outside air temperature is provided , and the control device converts the incoming water temperature detected by the incoming water temperature sensor, the outgoing water temperature detected by the outgoing hot water temperature sensor, and the outdoor air temperature detected by the outdoor air temperature sensor. 4. The heat pump hot water supply device according to claim 3 , wherein the two-way valve of the bypass circuit is operated in the opening direction and the opening of the second expansion device is controlled in the closing direction. The heat pump hot water supply apparatus according to any one of claims 1 to 6 , wherein carbon dioxide gas is used as the refrigerant.

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