JPH04254155A - Heat storage device - Google Patents

Abstract

PURPOSE:To provide a configuration capable of embodying higher temperature and lower temperature of heat storage with high efficiency in a heat storage device which supplies hot water and stores cold heat (ice heat) based on the application of a heat pump. CONSTITUTION:A two stage compression/one stage expansion cycle is constituted by connecting a lower stage compressor 1, an auxiliary condenser 2, and a higher stage compressor 3 in serial. An action side heat exchanger 4 comprising the auxiliary condenser 2 and the condenser heat-exchanges with water in a heat storage tank in either action side. The auxiliary condenser 2 heat- exchanges heat storage water in the lower part of the heat storage tank 11 while the action side heat exchanger 4 heat-exchanges with heat storage water in the upper part of the heat storage tank 11. This construction makes it possible to embody higher temperature and lower temperature in terms of heat storage temperature.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is used for hot water supply, ice storage, etc., to increase/lower the heat storage temperature and improve efficiency.
This invention relates to a heat storage device using a two-stage compression refrigeration cycle.

0002

[Prior Art] Conventionally, hot water supply systems or hot water heating/cooling systems using heat pumps have either used a single compressor and placed a condenser in a heat storage tank, or circulated water from the heat storage tank and exchanged heat with the condenser. The heat source was collected from outside air or solar heat in an evaporator.

[0003] In addition, an ice heat storage device using a heat pump uses one compressor, and an evaporator is placed inside a heat storage tank.
The waste heat was released into the outside air in a condenser.

0004

[Problems to be Solved by the Invention] However, with conventional water heaters that use heat pumps, it is difficult to raise the temperature, and the water supply temperature is limited to 60°C at most. The problem with this was that its efficiency decreased because the compression ratio between the high pressure of the condenser and the low pressure of the evaporator was large.

On the other hand, the ice heat storage device using a conventional heat pump is a countermeasure against the load at high outside temperatures in summer, and in order to generate ice, the evaporation temperature must be kept below 0°C. Even if this were to be realized, there was a problem in that the efficiency would be reduced because the compression ratio between the high pressure of the condenser and the low pressure of the evaporator was large.

[0006] The present invention solves these problems, and uses a two-stage compression refrigeration cycle in a heat storage device such as hot water supply or ice storage using a heat pump to efficiently raise and lower the heat storage temperature. The object of the present invention is to provide a heat storage device that can obtain heat.

[0007]

[Means for Solving the Problem] In order to solve this problem, the heat storage device of the present invention includes a low-stage compressor, an auxiliary condenser, a high-stage compressor, a working-side heat exchanger, a first throttle device, a gas-liquid separator,
In a main refrigeration cycle configured by connecting a second throttling device, a heat source side heat exchanger, etc. in series, the injection pipe above the gas-liquid separator is connected between the auxiliary condenser and the high-stage compressor. However, both the auxiliary condenser and the working side heat exchanger exchange heat with the heat storage tank water.

Further, the auxiliary condenser exchanges heat with the heat storage water in the lower part of the heat storage tank, and the working side heat exchanger exchanges heat with the heat storage water in the upper part of the heat storage tank.

Furthermore, the working side heat exchanger functions as a condenser, and the condensation temperature on the high stage side is controlled by controlling the opening degree of the second throttling device on the low stage side.

0010

[Function] With the above configuration, when the active heat exchanger is a condenser, heat is exchanged with the discharge refrigerant of the low stage compressor at an intermediate pressure in the auxiliary condenser at the bottom of the heat storage tank, and natural convection occurs inside the heat storage tank. As a result, the heat storage water in the upper part is also warmed, and in the upper part of the heat storage tank, heat is exchanged with the refrigerant discharged from the high-stage compressor that becomes high pressure in the condenser, making it possible to obtain a high temperature. At this time, since the temperature of the refrigerant sucked into the high-stage compressor is lowered by the auxiliary condenser, the temperature of the refrigerant discharged from the high-stage compressor is also lowered, making it possible to operate the two-stage compressor with high efficiency.

Furthermore, in the gas-liquid separator, the refrigerant whose pressure has been reduced to an intermediate pressure by the first throttle device is separated into a saturated gas refrigerant and a liquid refrigerant, which pass through the second throttle device to form an evaporator. The liquid refrigerant flowing into the heat source side heat exchanger collects more heat from the heat source because its latent heat of vaporization increases. Furthermore, the gas refrigerant separated in the gas-liquid separator is
Since the refrigerant is sucked into the high-stage compressor via the injection pipe, more refrigerant circulates in the condenser than the refrigerant circulating from the low-stage compressor, making it possible to increase the hot water supply capacity.

On the other hand, when the working side heat exchanger is an evaporator, the evaporation temperature in the evaporator is set to 0°C or lower in the upper part of the heat storage tank, and heat is exchanged with the refrigerant sucked in by the low-pressure compressor to lower the temperature. At the bottom of the heat storage tank, the auxiliary condenser exchanges heat with the refrigerant discharged from the low-stage compressor, which is at an intermediate pressure, making it easier to extract cooling water from the bottom of the heat storage tank. . In this case as well, the auxiliary condenser lowers the suction refrigerant temperature of the high-stage compressor, and the circulation of gas refrigerant from the gas-liquid separator promotes heat dissipation in the heat source side heat exchanger that serves as the condenser, resulting in high efficiency.・High-capacity two-stage compression operation is possible.

[0013] Furthermore, when the working side heat exchanger acts as a condenser and the condensation temperature on the high stage side is changed greatly, the opening degree of the second throttling device on the low stage side is controlled. When increasing the condensation temperature in the gas-liquid separator, reducing the opening of the second throttle device will increase the high pressure in the condenser, and the intermediate pressure will also increase, reducing the gas fraction in the gas-liquid separator.
A gas refrigerant mixed with a liquid component flows out from the upper part of the gas-liquid separator, and the degree of supercooling of the refrigerant that circulates through the condenser is kept approximately constant, resulting in a proper refrigeration cycle. Conversely, when lowering the condensation temperature in the condenser, increasing the opening degree of the second throttle device lowers the high pressure in the condenser, lowers the intermediate pressure, and increases the gas fraction in the gas-liquid separator. As a result, the refrigerant flowing out from the top of the gas-liquid separator becomes almost only gas components, and the degree of supercooling of the refrigerant that circulates through the condenser is kept almost constant, creating a proper refrigeration cycle and allowing the condensing temperature to fluctuate greatly. In either case, the degree of subcooling at the condenser outlet is optimized to achieve highly efficient two-stage compression operation.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A heat storage device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of a water heater using a heat storage device according to an embodiment of the present invention. As shown in the figure, a low stage compressor 1, an auxiliary condenser 2, a high stage compressor 3, a working side heat exchanger 4 serving as a condenser, a first throttle device 5-A, and a second throttle device 5-B.
, a heat source side heat exchanger 6 serving as an evaporator, etc. are connected in series to form a main refrigeration cycle. 1st
A gas-liquid separator 7 is provided between the throttle device 5-A and the second throttle device 5-B, and the connecting pipe between the first throttle device 5-A and the second throttle device 5-B is a gas-liquid separator. Connected to the bottom of the vessel 7,
An injection pipe 8 is connected from the top between the auxiliary condenser 2 and the high stage compressor 3. A high-pressure pressure detector 9 is attached to the discharge pipe of the high-stage compressor 3, and a low-pressure pressure detector 10 is attached to the suction pipe of the low-stage compressor 1. In this embodiment, the auxiliary condenser 2 is arranged at the lower part of the heat storage tank 11, the condenser 4 is arranged at the middle of the heat storage tank 11, and the auxiliary condenser 2 is arranged at the lower part of the heat storage tank 11.
A water supply pipe 12 is connected to the lower part of the tank, and a hot water supply pipe 13 is connected to the upper part of the tank.

[0016] A method of operating the heat storage device having such a configuration will be explained. The refrigerant circulating in the main refrigeration cycle includes a low-stage compressor 1, an auxiliary condenser 2, a high-stage compressor 3, an active side heat exchanger 4 that serves as a condenser, a first expansion device 5-A, and a gas-liquid separator 7. , the second expansion device 5-B, and the heat source side heat exchanger 6 which serves as an evaporator, and is sucked into the low stage compressor 1 again. In the lower part of the heat storage tank 11, heat is exchanged with the refrigerant discharged from the low stage compressor 1 which has an intermediate pressure in the auxiliary condenser 2, and the heat storage tank 11
Inside, the hot water at the top is also heated by natural convection. In the middle of the heat storage tank 11, heat is exchanged with the refrigerant discharged from the high-stage compressor 3, which reaches a high pressure in the condenser 4, and the hot water above the condenser 4 becomes even hotter. At this time, auxiliary condenser 2
As the refrigerant temperature decreases, the suction refrigerant temperature of the high-stage compressor 3 decreases, so the discharge refrigerant temperature of the high-stage compressor 3 also decreases, improving compressor efficiency and making the two-stage compressor highly efficient. It becomes possible to drive.

In the gas-liquid separator 7, the refrigerant whose pressure has been reduced to an intermediate pressure by the first throttle device 5-A is separated into a saturated gas refrigerant and a liquid refrigerant.
The liquid refrigerant flowing into the evaporator 6 via -B collects more heat from the heat source due to the increased latent heat of vaporization. The opening degree of the first throttle device 5-A on the higher stage side needs to be an appropriate opening degree in order to realize a two-phase state in the gas-liquid separator 7. Furthermore, the gas refrigerant separated in the gas-liquid separator 7 is passed from the upper part of the gas-liquid separator 7 to the high-stage compressor 3 via the injection pipe 8.
Therefore, more refrigerant is circulated in the condenser 4 than the refrigerant circulated from the low-stage compressor 1, so that the hot water supply capacity can be increased.

Furthermore, since the condensing temperature of the condenser 4 is determined from the high pressure detected by the high pressure detector 9, when increasing the condensing temperature in the condenser 4, the condensing temperature of the lower stage side is determined according to the detected high pressure. When the opening degree of the second throttle device 5-B is reduced, the high pressure in the condenser 4 increases, the intermediate pressure also increases, and the gas fraction in the gas-liquid separator 7 decreases. The gas refrigerant mixed with liquid components flows out from the upper part of the gas-liquid separator 7 via the injection pipe 8, so it joins with the refrigerant at the outlet of the auxiliary condenser 2, is discharged by the high-stage compressor 3, and is returned to the condenser. The degree of supercooling of the refrigerant circulating through the refrigeration system 4 is maintained approximately constant, resulting in a proper refrigeration cycle. Conversely, when lowering the condensation temperature in the condenser 4, increasing the opening degree of the second throttle device 5-B on the lower stage side in accordance with the detected high pressure reduces the high pressure in the condenser 4, and the intermediate The pressure also decreases and the gas fraction in the gas-liquid separator 7 increases, and the refrigerant flowing out from the upper part of the gas-liquid separator 7 becomes almost only gas components, and the degree of subcooling of the refrigerant circulating through the condenser 4 again is almost It is held constant, resulting in a proper refrigeration cycle.

Therefore, in any case where the condensation temperature on the high stage side is greatly varied, the second throttling device 5-B on the low stage side is used so that the degree of supercooling at the outlet of the condenser 4 is appropriate. By controlling the opening degree of the compressor, highly efficient two-stage compression operation is realized. Furthermore, even if the circulating amount of refrigerant discharged by the low-stage compressor 1 changes, the circulating refrigerant from the condenser 4 can be branched to the optimal amount of high-stage refrigerant by the second throttle device 5-B. Coupled with the simple configuration of the liquid separator 7, the degree of supercooling in the condenser 4 can be maintained to ensure stable and reliable operation.

FIG. 2 shows the configuration of an example in which a heat storage device according to an embodiment of the present invention is used as a device for both high temperature heat storage in winter and ice heat storage in summer. As shown in the figure, 1 to 11 are the same components as the water heater in FIG.
A water circulation circuit 13 and a plurality of fan coil units 14 installed in each room. The difference in this configuration from FIG. 1 is that the low-stage compressor 1, auxiliary heat exchanger 2, and high-stage compressor 3 are paired, and the working side heat exchanger 4 and heat source side heat exchanger 6 are also used for evaporation in the condenser. A four-way valve 15 was inserted so that it could also be used as a container.

In the case of high temperature heat storage in winter, arrow A in FIG.
When the four-way valve 15 is opened as shown in FIG. It becomes possible to realize this.

In the case of ice heat storage in the summer, when the four-way valve 15 is opened as shown by arrow B in FIG. 2, the heat source side heat exchanger 6 becomes a condenser, and the working side heat exchanger 4 becomes an evaporator. The second expansion device 5-B is located on the high stage side, and the first expansion device 5-A is located on the low stage side, and the refrigerant is separated into saturated gas refrigerant and liquid refrigerant in the gas-liquid separator 7. Therefore, in the upper part of the heat storage tank 11, the evaporation temperature in the working side heat exchanger 4, which serves as an evaporator, is set to 0°C or lower, and heat is exchanged with the suction refrigerant of the low-stage compressor 1, which has a low pressure, to obtain a low temperature and ice heat storage. It becomes possible to achieve high efficiency and high capacity. At the lower part of the heat storage tank 11, heat is exchanged in the auxiliary condenser 2 with the refrigerant discharged from the low-stage compressor 1, which has an intermediate pressure, so that the cooling water can be easily taken out from the lower part of the heat storage tank 11. In this case as well, the auxiliary condenser 2 lowers the suction refrigerant temperature of the high-stage compressor 3, and the gas-liquid separator 7
Since the gas refrigerant flows out from the upper part via the injection pipe 8, heat radiation in the heat source side heat exchanger 6, which serves as a condenser, is promoted, and highly efficient and high capacity two-stage compression operation is possible.

The arrangement and position of the auxiliary condenser 2 and the active heat exchanger 4 are not limited to those in this embodiment, and the heat storage water may be circulated from the heat storage tank 11. Further, the two throttle devices 5-A and 5-B may be constructed of capillary tubes, or a solenoid valve (not shown) may be arranged in the injection port 8 to control the outflow of the gas refrigerant. good. Further, the heat storage device of this embodiment may be used as a hot water supply/cooling/heating device or an ice heat storage/cooling device whose terminal side is constituted by a refrigerant circuit.

[0024]

Effects of the Invention As is clear from the description of the embodiments above, the heat storage device of the present invention comprises a low-stage compressor, an auxiliary condenser, a high-stage compressor, an active side heat exchanger, a first throttle device, The main refrigeration cycle is constructed by connecting the gas-liquid separator, second throttling device, heat source side heat exchanger, etc. in series, and the injection pipe above the gas-liquid separator is connected between the auxiliary condenser and the high-stage compressor. However, both the auxiliary condenser and the active heat exchanger are characterized by exchanging heat with the heat storage tank water.
Lower temperatures can be achieved using a highly efficient, high-capacity two-stage compression refrigeration cycle.

Furthermore, the auxiliary condenser exchanges heat with the heat storage water at the bottom of the heat storage tank, and the active side heat exchanger exchanges heat with the heat storage water at the top of the heat storage tank, so when the active side heat exchanger is a condenser,
In the lower part of the heat storage tank, heat is exchanged with the refrigerant discharged from the low-stage compressor at an intermediate pressure in the auxiliary condenser, and inside the heat storage tank, the heat storage water in the upper part is also warmed by natural convection. In the upper part of the heat storage tank, heat is exchanged with the discharge refrigerant of the high-stage compressor which becomes high pressure in the condenser, making it possible to obtain a high temperature. The evaporation temperature is set to 0℃ or less, and heat is exchanged with the suction refrigerant of the low-stage compressor, which has a low pressure, and a low temperature is obtained, making it possible to store ice heat. Since heat is exchanged with the refrigerant discharged from the compressor, it becomes easy to take out the cooling water from the lower part of the heat storage tank.

Furthermore, in the heat storage device of the present invention, when the working side heat exchanger acts as a condenser and the condensation temperature on the high stage side is greatly changed, the degree of supercooling at the outlet of the condenser is adjusted to be appropriate. Since the opening degree of the second throttling device on the low stage side is controlled, an appropriate degree of supercooling in the condenser can be maintained in any case where the condensing temperature is increased or decreased. Highly efficient two-stage compression operation can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a water heater using a heat storage device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a water heater using a heat storage device according to an embodiment of the present invention.

[Explanation of symbols]

1 Low stage compressor 2 Auxiliary condenser 3 High stage compressor 4 Working side heat exchanger 5 Squeezing device 6 Heat source side heat exchanger 7 Gas-liquid separator 8 Injection piping 9 High pressure pressure detector 10 Low pressure pressure detector 11 Heat storage tank 12 Circulation pump 13 Water circulation circuit 14 Fan coil unit

Claims (3)

[Claims] Claim 1: A low stage compressor, an auxiliary condenser, a high stage compressor, a working side heat exchanger, a first throttling device, a gas-liquid separator, a second throttling device, a heat source side heat exchanger, etc. are connected in series. In the main refrigeration cycle configured as follows, an injection pipe above the gas-liquid separator is connected between the auxiliary condenser and the high-stage compressor, and either of the auxiliary condenser and the working side heat exchanger Moga heat storage tank A heat storage device that exchanges heat with water. 2. The heat storage device according to claim 1, wherein the auxiliary condenser exchanges heat with the heat storage water in the lower part of the heat storage tank, and the working side heat exchanger exchanges heat with the heat storage water in the upper part of the heat storage tank. Claim 3: The working side heat exchanger acts as a condenser,
The heat storage device according to claim 1, wherein the condensation temperature on the high stage side is controlled by controlling the opening degree of the second throttle device on the low stage side.