JP2906508B2 - Heat pump water heater - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a water heater using a heat pump.

2. Description of the Related Art In recent years, hot water supply apparatuses that use heat pumps for electric water heaters to save energy and reduce size have become mainstream.

Conventionally, this type of hot water supply device using a heat pump generally has a circuit configuration shown in FIG. As shown in the figure, a compressor 21, a four-way valve 22, a condenser 23, a pressure reducing device 24, a check valve 25 provided in parallel with the pressure reducing device 24, and an air heat exchanger.
26 are connected sequentially, and an electric heater 28
A hot water storage tank 29, a water circulation pump 30 for circulating water in the hot water tank 29, a heat pump heating heat exchanger 31 having a heat exchange relationship with the condenser 23, and a hot water supply circuit sequentially connected to the upper part of the hot water tank 29. Then, the condenser 23 and the heat pump heating heat exchanger are condensed by the heat of condensation of the heat pump by the refrigerant circuit.
This is a system in which water is heated through the hot water storage tank 31 and gradually stored from above the hot water storage tank 29.

Problems to be Solved by the Invention However, in such a conventional heat pump water heater, when the outside air temperature in winter decreases, frost may form on the air heat exchanger 26, and the heating capacity may decrease. In order to prevent this, the refrigerant circulation direction of the refrigerant circuit is reversed by the four-way valve 22, the heat is removed from the hot water by the heat pump heating heat exchanger 31, and the heat is released by the air heat exchanger 26 through the compressor 21. Thaws frost on the circuit. Therefore, at this time, there has been a problem that the water which has been deprived of heat by the heat pump heating heat exchanger 31 and has a low temperature flows into the high temperature portion above the hot water storage tank 29, so that the temperature becomes lower than a temperature at which hot water can be discharged.
Further, even if the hot water temperature and the amount of hot water in the hot water storage tank 29 are insufficient with respect to the hot water supply load, the entire capacity of the hot water storage tank 29 must be heated by the heater 28, which takes time and is necessary for hot water supply. Heating the above volume is not economical.

The present invention has been made to solve the above-described problems, and has as its object to provide a heat pump water heater capable of supplying hot water to an upper part of a hot water tank without always cooling the same, and supplying a hot water heat quantity corresponding to a hot water supply load. I have.

Means for Solving the Problems In order to achieve the above object, the present invention provides a compressor, a four-way valve, a condenser, a decompression device, a check valve arranged in parallel with the decompression device, and air. A first temperature detector provided at a refrigerant inlet of the air heat exchanger, a hot water storage tank having a second temperature detector at an upper portion, the refrigerant closed circuit having a heat exchanger sequentially connected thereto, A water circulation pump connected to the lower part of the hot water tank, a heat pump heating heat exchanger having a heat exchange relationship with the condenser, and an electric heater having one end connected to the heat pump heating heat exchanger and the other end connected to the upper part of the hot water tank. A hot water supply circuit in which heating heat exchangers are sequentially connected, and a third temperature detector provided between the heat pump heating heat exchanger and the electric heater heating heat exchanger; The direction of the refrigerant flow in the four-way valve is turned off by a signal. At the same time, power is supplied to the electric heater provided in the electric heater heating heat exchanger. Then, from the difference between the temperature of the water temperature detected by the third temperature detector and the temperature of the water temperature detected by the second temperature detector that detects the temperature of the water flowing out of the heat pump heating heat exchanger, The input of the electric heater is controlled so that the hot water temperature becomes substantially equal to the temperature detected by the second temperature detector.

According to the present invention, the low-temperature water in the lower portion of the hot water tank flows into the heat pump heating heat exchanger by driving the water circulation pump, and the circulating water receives heat of condensation of the condenser provided in the refrigerant circuit. The temperature rises, and then flows into the hot water storage tank again from the upper part of the hot water storage tank through an electric heater heating heat exchanger provided next. By repeating this circulation, the water temperature in the hot water storage tank rises. At this time, if the outside air temperature in winter decreases and frost forms on the air heat exchanger to reduce the heating capacity of the refrigerant circuit, the first temperature detector detects the frost formation state, and the detection signal indicates the frost formation state. At the same time as the flow direction of the refrigerant in the valve is switched, energization of the electric heater of the electric heater heating heat exchanger is controlled. At that time, the condenser that originally performs a condensing operation of the refrigerant circuit is changed to an evaporator that performs an evaporating operation,
The refrigerant therein takes heat from the hot water sent from the hot water storage tank by the water circulation pump through the heat pump heating heat exchanger, evaporates and evaporates, and flows into the compressor through the four-way valve. The gaseous refrigerant is compressed therein and flows into the air heat exchanger, where the heat generated by the condensation of the air heat exchanger, the heat taken from the hot water, and the compression heat of the compressor are obtained. To dissolve the frost and condense and liquefy at the same time, pass through the check valve, and return to the condenser provided inside the heat pump heating heat exchanger. On the other hand, in the hot water supply circuit, water whose temperature has been reduced due to heat deprived by the heat pump heating heat exchanger is detected by the third temperature detector, and the detected temperature and the second temperature detection provided in the upper part of the hot water storage tank are detected. The input of the electric heater is controlled so that the hot water temperature after passing through the electric heater heating heat exchanger becomes substantially equal to the temperature detected by the second temperature detector from the difference from the detected temperature of the heater. Therefore, the cooled water does not flow into the high-temperature water existing above the hot water storage tank. Further, when the heat storage amount is insufficient for the hot water supply load, that is, when the hot water temperature is low, the hot water heated by the heat pump heating heat exchanger is further heated by the electric heater heating heat exchanger, so that Hot water can be obtained, and hot water can be directly discharged to the terminal.

Embodiment An embodiment of the present invention will be described below with reference to FIG.

In the drawing, solid arrows indicate the flow direction of the refrigerant during the heat pump heating operation, and dashed-dotted arrows indicate the flow direction of the refrigerant during the defrost operation. Refrigerant circuit 1A (heat pump) is compressor 1
And a four-way valve 2 for switching the flow direction of the refrigerant in the heat pump heating operation and the defrosting operation in the direction of the double arrow shown in the figure. The condenser 3 is connected to the condenser 3, and the condenser 3 and the
And a check valve 5 that allows the refrigerant to flow in the direction of an alternate long and short dash line shown in the drawing during the heat pump defrosting operation, and connects the pressure reducing device 4 and the check valve 5 to both heat absorption and heat release of the refrigerant. The air heat exchangers 6 having functions are sequentially connected to form a closed circuit, and a refrigerant is sealed. The first refrigerant inlet portion of the air heat exchanger 6, that is, the first refrigerant inlet portion of the air heat exchanger 6 during the heat pump heating operation of the refrigerant circuit 1A.
The switching operation of the four-way valve 2 and the input of the electric heater 8 of the hot water supply circuit 9A described later are controlled by the detection signal of the first temperature detector 7.

On the other hand, the hot water supply circuit 9A connects a water circulation pump 10 for circulating water in the hot water tank 9 to a lower portion of the hot water tank 9 for storing hot water,
The outlet of the water circulation pump 10 is connected to a heat pump heating heat exchanger 11 having a heat exchange relationship with the condenser 3 provided inside the condenser 3 provided in the refrigerant circuit 1A. An electric heater 8 is connected to the other end of the heat pump heating heat exchanger 11.
And the other end of the electric heater heating heat exchanger 12 is connected to the upper part of the hot water storage tank 9 so that hot water can be discharged together with the water circulation circuit. . A second temperature detector is provided above the hot water storage tank 9, and a third temperature detector is provided between the heat pump heating heat exchanger 11 and the electric heater heating heat exchanger 12, and the second temperature detector is provided. The input of the electric heater 8 is controlled by the signal of the detected temperature difference between the temperature detector 13 and the third temperature detector 14.

 Next, the operation in the above configuration will be described.

First, during the heat pump heating operation, the refrigerant circuit 1A
When the compressor 1 is driven, the refrigerant is compressed and a high-temperature and high-pressure refrigerant gas is generated. This refrigerant gas passes through the four-way valve 2,
It flows into the condenser 3, where it undergoes liquefaction by condensation to generate heat. The liquefied refrigerant is supplied to the pressure reducing device 4
Into the air heat exchanger 6, absorbs the heat of the air, evaporates and gasifies, returns to the compressor 1 through the four-way valve 2, and performs the heat pump operation of the refrigerant circuit 1A. Complete the cycle. On the other hand, in the hot water supply circuit 9A, the low-temperature water in the lower part of the hot water storage tank 9 sent by the driving of the water circulation pump 10 flows into the heat pump heating heat exchanger 11, and receives the condensing heat generated from the condenser 3 and rises. The hot water storage tank 9 is heated and then passed through an electric heater heating heat exchanger 12 provided next.
The water flows into the upper part and flows out to the outside. Then, by continuing these operations, the water in the hot water storage tank 9 is boiled.

Next, regarding the operation at the time of the defrosting operation, the temperature of the refrigerant flowing through the air heat exchanger 6 is low when the outside air temperature is low, such as in winter, during the heat pump heating operation, so that the air heat exchanger 6 is frosted and the heat exchange characteristics are reduced. If the operation is further continued in this frosted state, the temperature of the refrigerant gradually decreases, the heat absorption of the refrigerant decreases, and the operation efficiency decreases. Therefore, in order to prevent this phenomenon, the first temperature detector 7 provided on the refrigerant inlet side detects the refrigerant temperature of the air heat exchanger 6 changed by frosting,
Based on this detection signal, the flow direction of the refrigerant in the four-way valve 2 is controlled to be switched in the direction of the dashed line in FIG. At this time, the gaseous refrigerant is compressed by the compressor 1, passes through the four-way valve 2, and flows into the air heat exchanger 6. Then, here, the condensing action of the air heat exchanger 6 is performed to radiate the heat of condensation, and the frost attached to the air heat exchanger 6 is melted (defrosted), and at the same time, the gaseous refrigerant is liquefied by the condensing action. Then, it flows into the condenser 3 through the check valve 5. Here, the refrigerant takes heat from the hot water sent from the hot water storage tank 9 through the heat pump heating heat exchanger 11 and turns into a vaporized gaseous refrigerant, passes through the four-way valve 2 and passes through the compressor 1. Go back. On the other hand, in the hot water supply circuit 9A, water which has been deprived of heat by the heat pump heating heat exchanger 11 and has become low temperature flows into the electric heater heating heat exchanger 12. Here, the electric heater 8
Is heated by the above-mentioned signal of the first temperature detector 7, so that the inflow water is heated. At that time,
The third temperature detector 14 is a heat pump heating heat exchanger 11
At the same time as detecting the low water temperature at the outlet of the tank, and comparing the result of detection of the temperature of the hot water above the hot water storage tank 9 by the second temperature detector 13 with the temperature detected by the third temperature detector 14 as shown in FIG. The input of the electric heater 8 is controlled such that the temperature of the hot water after passing through the electric heater heating heat exchanger is substantially equal to the temperature detected by the second temperature detector 13 from the temperature difference between the detected temperatures of the temperature detectors 13. Therefore, the hot water heated by the electric heater heating heat exchanger 12 can flow into the hot water storage tank 9 without cooling the high temperature water.

Further, when the temperature of the hot water in the hot water storage tank 9 is further increased, or when the hot water in the hot water storage tank 9 is insufficient due to the hot water being supplied and the hot water temperature is low, the heat pump heating heat exchanger 11 is used.
The hot water heated in
And heated to a high temperature and stored in the hot water storage tank 9 or the hot water can be directly discharged to the terminal. Therefore, the heater is energized only for the required amount of hot water such as hot water, so that it is economical and the size of the hot water storage tank 9 can be reduced.

According to the heat pump water heater of the present invention, as apparent from the above description of the embodiment, the compressor, the four-way valve, the condenser, the pressure reducing device, and the reverse device arranged in parallel with the pressure reducing device. It has a refrigerant closed circuit in which a stop valve and an air heat exchanger are sequentially connected, and has a first temperature detector provided at a refrigerant inlet of the air heat exchanger and a second temperature detector at an upper portion. A hot water tank,
A water circulation pump connected to the lower part of the hot water tank, a heat pump heating heat exchanger having a heat exchange relationship with the condenser, and an electric power having one end connected to the heat pump heating heat exchanger and the other end connected to the upper part of the hot water tank. A hot water supply circuit in which heater heating heat exchangers are sequentially connected, and a third temperature detector provided between the heat pump heating heat exchanger and the electric heater heating heat exchanger, wherein the first temperature detector The flow direction of the refrigerant of the four-way valve is switched by the signal of the above, the electric heater provided in the electric heater heating heat exchanger is energized, and further detected by the second temperature detector and the third temperature detector. The input of the electric heater is controlled such that the temperature of the hot water after passing through the electric heater heating heat exchanger is substantially equal to the temperature detected by the second temperature detector from the difference between the temperatures thus obtained. Thus, even if the outside air temperature decreases in winter or the like and the air heat exchanger is frosted, the defrosting operation is performed by the signal of the first temperature detector, and the inside of the heat pump heating heat exchanger is also operated during the defrosting operation. The second and third electric heaters of the electric heater heating heat exchanger provided in front of the hot water tank so that the hot water whose temperature has dropped in Since the temperature is controlled by a signal from the temperature detector, a constant hot water temperature can be obtained irrespective of a decrease in outside air temperature in winter or the like.

If you want to obtain a higher hot water supply temperature, or if water is supplied by tapping and the temperature of the hot water in the hot water storage tank decreases, the hot water heated by the heat pump heating heat exchanger is further heated by an electric heater heating heat exchanger. Be able to
Since heating can be performed according to the temperature and amount required for tapping, it is economical and the size of the hot water storage tank can be reduced.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a heat pump water heater according to one embodiment of the present invention, and FIG. 2 is a circuit diagram of a conventional heat pump water heater. DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Four-way valve, 3 ... Condenser, 4 ... Decompression device, 5 ... Check valve, 6 ... Air heat exchanger, 7 ... First
Temperature detector, 8 ... electric heater, 9 ... hot water tank, 10 ...
… Water circulation pump, 11 …… Heat pump heating heat exchanger, 12
... electric heater heating heat exchanger, 13 ... second temperature detector, 14 ... third temperature detector.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) F24D 17/00 F24H 1/00 F25B 1/00

Claims (1)

(57) [Claims] 1. A refrigerant closed circuit in which a compressor, a four-way valve, a condenser, a pressure reducing device, a check valve disposed in parallel with the pressure reducing device, and an air heat exchanger are sequentially connected. A first temperature detector provided at a refrigerant inlet of the air heat exchanger;
A hot water storage tank having an upper temperature detector, a water circulation pump connected to the lower part of the hot water tank, a heat pump heating heat exchanger having a heat exchange relationship with the condenser, and one end connected to the heat pump heating heat exchanger. A hot water supply circuit in which an electric heater heating heat exchanger having the other end connected to the upper part of the hot water storage tank is sequentially connected, and a third temperature detector is provided between the heat pump heating heat exchanger and the electric heater heating heat exchanger. And switching the flow direction of the refrigerant in the four-way valve according to the signal of the first temperature detector, energizing the electric heater provided in the electric heater heating heat exchanger, and further connecting the second temperature detector and the second The electric heater so that the temperature of the hot water after passing through the electric heater heating heat exchanger becomes substantially equal to the temperature detected by the second temperature detector based on the difference between the temperatures detected by the respective temperature detectors. Heat pump hot water supply device for controlling the input.