JPS5950022B2 - Heat pump water heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat pump type water heater, and more particularly to a novel heat pump type water heater having a configuration in which a heat storage device is connected to a supply heat exchanger.

A conventionally known heat pump water heater has a configuration as shown in FIG.

In Figure 3, 1 is a compressor, 2 is a four-way valve, 3 is a heat exchanger for hot water supply, 4 is a heat exchanger on the non-use side, 6 is a throttle device such as an expansion valve, and 7 is a heat exchanger on the supply side. , and a water supply pipe 12 and a hot water supply pipe 13 are connected to the hot water supply heat exchanger 3, and
The utilization side heat exchanger 4 is provided with an air blower 5, and the supply side heat exchanger 7 is also provided with an air blower 14.

When hot water is not being supplied in the heat pump water heater configured as described above, the four-way valve 2 is switched as shown by the dotted line in the figure, and the gaseous refrigerant compressed by the compressor 1 is transferred in all directions as shown by the dotted line arrow in the figure. After passing through the valve 2, it is introduced into the supply-side heat exchanger 7, where it is cooled and condensed to become a high-temperature, high-pressure liquid.

The liquid refrigerant is then depressurized through the throttle device 6, and then
It evaporates in the heat exchanger 4 on the non-use side and becomes a low-temperature, low-pressure gas refrigerant.

In this case (that is, during non-hot water supply operation), the non-use side heat exchanger 4 functions as a heat collector, and the refrigerant takes heat from the air sent by the blower 5.

On the other hand, the water supply to the hot water heat exchanger 3 has been stopped and it does not function as a heat exchanger, so the gas refrigerant is supplied to the four-way valve 2 again.
The air is sucked into the compressor 1 through the

During hot water supply operation, the four-way valve 2 is switched to the solid line state shown in the figure.
After the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 passes through the four-way valve 2 as indicated by the solid arrow in the figure, it is introduced into the hot water supply heat exchanger 3.

In this case, since cold water is supplied to the hot water heat exchanger 3 from the water supply pipe 12, the gaseous refrigerant condenses and liquefies, and at the same time,
Hot water can be obtained from the hot water pipe 13.

The liquid refrigerant is then introduced into the non-use side heat exchanger 4,
Since the blower 5 is stopped during hot water supply operation, the non-use side heat exchanger 4 does not function as a heat exchanger, and therefore the liquid refrigerant is not cooled in the non-use side heat exchanger 4.

The liquid refrigerant that has passed through the heat exchanger 4 on the non-use side is further reduced in pressure in the expansion device 6, and then in the heat exchanger 7 on the supply side, it absorbs heat from the air etc. supplied by the blower 14 etc. and evaporates. , and is sucked into the compressor through the four-way valve 2 again.

In the above-mentioned known heat pump water heater, the refrigerant pressure at point a on the suction side of the compressor was relatively low, so the amount of work required by the compressor to supply hot water at a predetermined temperature was relatively low. It had the disadvantage that it was large and the hot water temperature could not be raised very high.

Furthermore, when the compressor is operated to supply hot water at a high temperature, the discharge temperature of the compressor becomes high, and as a result, there is a drawback that troubles with the compressor tend to occur.

This invention was made to eliminate the above-mentioned drawbacks, and an object of the invention is to provide a heat pump water heater that can supply hot water at a higher temperature without increasing the amount of work required by the compressor.

The feature of this invention is that a heat storage device is connected to the supply side heat exchanger,
By supplying the heat stored in the heat storage device during non-hot water supply operation to the supply side heat exchanger during hot water supply operation, the pressure of the refrigerant before being sucked into the compressor is increased, thereby reducing the required work of the compressor. The goal is to reduce the amount of water and at the same time make it possible to supply hot water at a higher temperature.

An embodiment of the present invention will be described below with reference to FIG. 1, but explanations of the same parts as those shown in FIG. 3 will be omitted unless necessary.

In FIG. 1, 8 is an insulated and sealed heat storage tank used as a heat storage, and water in the heat storage tank 8 is supplied into the supply side heat exchanger 7 by a pump 9 installed in the supply piping. It has become.

The solar heat collector 1 is also connected to the heat storage tank 8 via other piping.
0 is connected, and water in the heat storage tank 8 is sent to the solar heat collector 10 by a pump 11 provided in the pipe.

(Although other suitable heat sources may be used instead of the solar collector 10, it is not necessary to provide any particular heat source.

) Next, the operation of the heat pump water heater of the present invention having the above-mentioned configuration will be explained.

During non-hot water supply operation (heat storage operation), the four-way valve 2 conducts as shown by the dotted line in the figure, and the high-temperature, high-pressure gaseous refrigerant leaving the compressor 1 passes through the four-way valve 2 as shown by the dotted line in the figure before being supplied. It enters the side heat exchanger 7.

Since hot water in the heat storage tank 8 is supplied to the supply side heat exchanger 7 by the pump 9, the gaseous refrigerant is cooled by the hot water and turned into liquid refrigerant, and then enters the expansion device 6 and is depressurized.

On the other hand, the hot water whose temperature has increased is returned to the heat storage tank 8 and held there, and sent to the solar collector 10 by the pump 11 at an appropriate time, where it becomes even hotter and returns to the heat storage tank 8 again.

On the other hand, the liquid refrigerant that has passed through the expansion device 6 evaporates in the non-use side heat exchanger 4, and at that time, it absorbs heat from the air sent by the blower 5 and becomes a gas refrigerant.

The number of revolutions and the amount of air blown by the blower 5 are controlled according to the outside temperature, and therefore the heat carried away by the gaseous refrigerant also changes accordingly.

The gaseous refrigerant that exits the non-use side heat exchanger 4 is transferred to the hot water supply heat exchanger 3
However, in this case, since the water supply pipe 12 is not supplying water to the heat exchanger 3, the gaseous refrigerant is drawn into the compressor 1 through the refrigerant valve 2 as it is.

During hot water supply operation, the four-way valve 2 is switched as shown by the solid line, so the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 1 passes through the four-way valve 2 as shown by the solid line arrow, and then enters the hot water heat exchanger 3. There, it exchanges heat with the cold water supplied from the water supply pipe 12, condenses, and turns into liquid refrigerant.

On the other hand, the cold water is heated to become hot water, which is supplied to the outside from the hot water pipe 13.

On the other hand, the liquid refrigerant passes through the non-use side heat exchanger 4 (in this case, the blower 5 is stopped and the heat exchanger 4 does not function as a heat exchanger).

) After entering the expansion device 6 and being depressurized, the supply side heat exchanger 7
enters and evaporates.

In this case, since hot water in the heat storage tank 8 is supplied into the heat exchanger 7 by the pump 9, a large amount of heat is consumed for evaporation when the liquid refrigerant evaporates, and therefore, the supply side heat The pressure of the gaseous refrigerant leaving the exchanger 7 is considerably higher than that in a conventional heat pump water heater, and therefore, the state of the gaseous refrigerant before being sucked into the compressor 1 is at a higher pressure than in a conventional heat pump water heater. It becomes.

For this reason, the discharge pressure at the discharge port of the compressor 1 is also higher than before, and as a result, the amount of heat given to the water supply in the hot water supply heat exchanger 3 is also increased, so hot water can be supplied at a higher temperature than in conventional water heaters. It becomes possible.

Additionally, since the pressure of the gas refrigerant before being sucked into the compressor is higher than before, the power required for the compressor is reduced, and the overall efficiency of the water heater is improved.

FIG. 2 is a comparative diagram of a Mollier diagram during hot water supply operation of a conventional heat pump type water heater and a Mollier diagram during hot water supply operation of the heat pump type water heater of the present invention, and the dotted lines a1b, c, -dl What is displayed is the heat cycle of a conventional water heater, and the solid line a2-b2-
C2-d2 shows the heat cycle in the water heater of the present invention.

In FIG. 2, al and C2 represent the pressure and enthalpy of the refrigerant at the inlet a of the supply heat exchanger 7, and bl and b2 represent the pressure and enthalpy of the refrigerant at the outlet of the supply heat exchanger 7, that is, at the point on the compressor suction side. Indicates the pressure and enthalpy of the refrigerant, C
1 and C2 indicate the pressure and enthalpy of the refrigerant at the compressor outlet C, and dl and C2 indicate the pressure and enthalpy of the refrigerant at the point d on the inlet side of the expansion device 6.

In addition, in FIG. 2, Ll represents the compressor work equivalent in the conventional water heater, L2 represents the compressor work equivalent in the water heater of the present invention, C1 and C2 represent the discharge temperature curve of the compressor, and KA represents the compressor work equivalent. KB is the saturated liquid line of the refrigerant, and KB is the saturated vapor line of the refrigerant.

As can be seen from FIG. 2, in the water heater of the present invention, the refrigerant pressure at the inlet of the supply heat exchanger 7 and the compressor inlet is higher than that in the conventional water heater, and the compressor discharge pressure and the throttling device The pressure at the inlet of the water heater is also higher than that of conventional water heaters, so the compressor work is reduced and therefore, with the same compressor work, the hot water temperature can be higher than that of conventional water heaters.

In addition, when supplying hot water at the same temperature, both the compressor discharge temperature and the amount of compressor work required are lower than in conventional water heaters, improving the overall efficiency of the water heater and eliminating the risk of compressor trouble. Effects such as this can be obtained.

As described above, according to the present invention, a new heat pump water heater is provided which eliminates the drawbacks of conventional heat pump water heaters, but the embodiments shown in the accompanying drawings are merely illustrative. When carrying out the invention, various changes and modifications can be made within the scope of the claims.

For example, a heat storage device other than the illustrated heat storage tank may be used as the heat storage device, and another heat source may be used instead of the solar collector.

Furthermore, there is no need to provide a special heat source such as a solar heat collector.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the configuration of the pump-type water heater of the present invention, Fig. 2 is a Mollier diagram for explaining the effects of the pump-type water heater of the present invention, and Fig. 3 is a Mollier diagram for explaining the effects of the pump-type water heater of the present invention. 1 is a schematic diagram showing the configuration of a conventional heat pump water heater. In the figure, 1...Compressor, 2...Four-way valve, 3...Hot water supply heat exchanger, 4...Non-use side heat exchanger Container, 6... Squeezing device, 7...
...Supply side heat exchanger, 8... Heat storage tank. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A non-use side heat exchanger that acts as a heat collector during non-hot water supply operation, and a supply side heat exchanger that acts as a heat collector during hot water supply operation and as a radiator during non-hot water supply operation. , a hot water supply heat exchanger that acts as a heat exchanger only during hot water supply operation, a throttling device connected between the non-use side heat exchanger and the supply side heat exchanger, and the supply side heat exchanger. A heat pump type water heater having a four-way valve connected to the hot water supply heat exchanger, and a compressor connected to the supply side heat exchanger and the hot water supply heat exchanger via the four-way valve. A heat storage device is connected to the heat exchanger on the supply side, heat is stored in the heat storage device during non-hot water supply operation, and refrigerant is supplied to the supply side heat exchanger using the heat extracted from the heat storage device during hot water supply operation. A heat pump water heater characterized by being configured to heat the water. 2. The heat pump water heater according to claim 1, wherein a heat storage tank is provided as the heat storage device, and a solar heat collector is connected to the heat storage tank.