JP2002286319A - Heat storage type air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat storage type air conditioner in which an amount of melted ice during a cooling operation using stored heat is increased in a heat transfer pipe of a heat storage type heat exchanger to which thick ice adheres upon heat storage operation, and an amount of melted ice during the cooling operation using stored heat is decreased in a heat transfer pipe to which thin ice adheres upon heat storage operation. SOLUTION: In the heat storage type air conditioner, the heat storage operation and the cooling operation using the stored heat are carried out. In the heat storage operation, non-azeotrope refrigerant discharged from a compressor 1 is condensed, and then, the condensed refrigerant is thermally insulated and expanded to enter a heat storage device 8 having a heat storage medium 10 and the heat storage type heat exchanger 11 and to stick ice thereto. In the cooling operation using the stored heat, the non-azeotrope refrigerant discharged from the compressor is allowed to enter the heat storage device 8 to which the ice adheres and to be condensed, and the condensed refrigerant is thermally insulated and expanded and evaporated in a using side heat exchanger 15. The flowing directions of the refrigerant in the heat storage type heat exchanger of the heat storage device are the same both during the heat storage operation and during the cooling operation using the stored heat.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat storage type air conditioner, and more particularly to a heat storage type air conditioner using a non-azeotropic mixed refrigerant as a heat transfer medium.

[0002]

2. Description of the Related Art A regenerative air conditioner stores cold heat in a heat storage medium during off-peak hours of a cooling load and reduces the power demand at the peak of the cooling load and increases the power demand at off-peak times. Is intended to contribute to the cooling operation.

FIG. 4 shows a configuration of a conventional regenerative air conditioner. In this figure, 1 is a compressor, 2 is a compressor for cooling using heat storage, 3 is a first flow path switching valve connecting the discharge portions of both compressors, 4 is a four-way valve, and 5 is a non-use side heat. Exchanger,
Reference numeral 6 denotes a second flow path switching valve, 7 denotes a first throttle device, 8 denotes a heat storage device, which includes a heat storage tank 9, a heat storage medium 10 such as water housed therein, and a heat storage heat exchanger 11. Have. The inlet end 11A of the heat storage heat exchanger 11 is connected to the first expansion device 7. Reference numeral 12 denotes a third flow path switching valve connected between the outlet end 11B of the heat storage heat exchanger 11 and the suction sections of the two compressors, and reference numeral 13 denotes an outlet end 11B of the heat storage heat exchanger 11 and heat storage cooling. A fourth flow path switching valve connected to the discharge section of the compressor 2 for use, 14 a second throttle device, and 15 a use side heat exchanger. A non-azeotropic mixed refrigerant such as R407C is used as the refrigerant. The solid arrows in the drawing indicate the flow of the refrigerant during the heat storage operation, and the broken arrows indicate the flow of the refrigerant during the heat storage cooling operation.

Next, the operation of the conventional regenerative air conditioner will be described. First, a heat storage operation for storing cold heat in the heat storage device will be described. The gas refrigerant discharged from the compressor 1 and the gas refrigerant discharged from the heat storage cooling compressor 2 and joined through the first flow path switching valve 3 are condensed in the non-use side heat exchanger 5 through the four-way valve 4. Is done. The condensed refrigerant is
Adiabatically expands in the first expansion device 7 through the flow path switching valve 6 and enters a gas-liquid two-phase state, flows into the heat storage heat exchanger 11 of the heat storage device 8 from the inlet end 11A and evaporates. At this time, heat exchange occurs with the heat storage medium 10 in the heat storage tank 9, and ice adheres concentrically to the heat transfer tubes of the heat storage heat exchanger 11. The evaporated refrigerant returns to the compressors 1 and 2 from the outlet end 11B via the third flow path switching valve 12.

[0005] Non-azeotropic mixed refrigerants used as refrigerants include:
The saturation temperature differs depending on the state of the refrigerant, and at the same pressure, the saturation temperature is lower in the liquid state than in the gas state. Therefore, when the pressure loss in the heat storage heat exchanger 11 when flowing into the heat storage heat exchanger 11 of the heat storage device 8 is 0 (kg / cm ² ),
The evaporating temperature of the outlet end 11B of the heat storage heat exchanger 11 is higher than that of the inlet end 11A. For this reason, as shown in FIG. 5 which is a cross-sectional view of the heat transfer tube of the heat storage heat exchanger 11, the thickness of the ice 10A concentrically adhering to the heat transfer tube of the heat storage heat exchanger is closer to the inlet side, that is, to the left side of the figure. And the outlet side, that is, the right side in the figure, becomes thinner.

Next, a cooling operation utilizing heat storage will be described. The gas refrigerant discharged from the heat-storage cooling compressor 2 flows into the heat storage heat exchanger 11 of the heat storage device 8 from the outlet end 11B via the fourth flow path switching valve 13, and the heat storage heat exchanger 11
Is condensed by ice adhering to the heat transfer tubes. At this time, in the heat storage heat exchanger 11, the ice 10A attached to the heat transfer tube is concentrically melted, but the outlet end 11 serving as a refrigerant inflow portion is formed.
Since the condensation temperature of B is higher than that of the inlet end 11A serving as the outlet, the amount of melting near the outlet end 11B is larger, and the amount of melting decreases toward the inlet end 11A. FIG. 6 shows this state, in which the outer circle of hatching shows the amount of ice 10A attached during the heat storage operation as in FIG. 5, and the inner circle 10B without hatching shows the melting during the cooling operation using heat storage. Indicates the amount. The refrigerant condensed in the heat storage device 8 adiabatically expands in the first and second expansion devices 7 and 14, evaporates in the use side heat exchanger 15, and then the four-way valve 4.
Is returned to the heat-storage cooling compressor 2.

[0007]

The conventional regenerative air conditioner is constructed as described above, and the direction of the refrigerant flowing through the regenerator 11 of the regenerator 8 is reversed between the regenerative operation and the regenerative cooling operation. Therefore, the heat transfer tube to which thick ice adheres during heat storage operation has a small amount of ice melted during cooling operation using heat storage, and the heat transfer tube to which thin ice adheres during heat storage operation melts ice during cooling operation using heat storage. The amount increases. Therefore, when icing and melting of ice by the heat storage operation and the heat storage cooling operation are repeated, ice gradually grows on the inlet end 11A side of the heat storage heat exchanger 11 and the ice thickness increases, so that as shown in FIG. 7, on the inlet end 11A side, that is, on the left side of FIG. When blocking occurs, a blockage portion 10C of water surrounded by ice is generated, and when this portion becomes iced, a stress is applied to the heat transfer tube due to volume expansion, and the heat transfer tube is damaged. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem. In a heat transfer tube to which thick ice adheres during a heat storage operation, the amount of ice melted during a heat storage cooling operation increases.
It is an object of the present invention to provide a heat storage type air conditioner in which a heat transfer tube to which thin ice adheres during heat storage operation reduces the amount of ice melted during heat storage cooling operation.

[0009]

A regenerative air conditioner according to the present invention has a heat storage medium and a heat storage heat exchanger after condensing a non-azeotropic mixed refrigerant discharged from a compressor and then adiabatically expanding the refrigerant. Heat storage operation in which ice flows into the heat storage device to deposit ice, and non-azeotropic mixed refrigerant discharged from the compressor flows into the heat storage device after icing to condense, and the condensed refrigerant is adiabatically expanded to utilize heat on the utilization side. In the regenerative air conditioner that performs the heat storage cooling operation in which the heat is evaporated by the exchanger, the direction of the refrigerant flowing in the heat storage heat exchanger of the heat storage device is the same in both the heat storage operation and the heat storage cooling operation. It is made to become.

[0010] The regenerative air conditioner according to the present invention also includes a compressor for compressing a non-azeotropic mixed refrigerant, a non-use side heat exchanger for condensing refrigerant discharged from the compressor, and a condensed refrigerant. An adiabatic expansion device, a heat storage device having a heat storage medium and a heat storage medium having an inlet end connected to the expansion device, and a heat storage device provided between an outlet end of the heat storage heat exchanger and a suction portion of the compressor. A switching valve that opens only during operation, a switching valve that is provided between the discharge part of the compressor and the inlet end of the heat storage heat exchanger, and that opens only during cooling operation using heat storage, the outlet end of the heat storage heat exchanger, and other throttles. It is provided with a switching valve that is provided between the heat exchanger and the heat exchanger and that is opened only during the cooling operation using heat storage, and a use-side heat exchanger connected to another expansion device.

[0011] In the regenerative air conditioner according to the present invention, the non-azeotropic mixed refrigerant is R407C.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a refrigerant circuit diagram showing the configuration of the first embodiment. In this figure, the same or corresponding parts as those in FIG. The difference from FIG. 4 is that the fifth flow path switching valve 20 that opens the inlet end 11A of the heat storage heat exchanger 11 and the discharge portion of the heat storage cooling compressor 2 only during the heat storage cooling operation.
And the outlet end 1 of the heat storage heat exchanger 11
1B and the second expansion device 14 are connected via a sixth flow path switching valve 21 that opens only during the cooling operation using heat storage. In addition, in FIG. 1, 22 is a non-use side heat exchanger 5
And a seventh flow path switching valve provided between the outlet side of the second flow path and the outlet side of the sixth flow path switching valve 21.

Next, the operation of this embodiment will be described. First, the heat storage operation will be described. The gas refrigerant discharged from the compressor 1 and the gas refrigerant discharged from the heat storage cooling compressor 2 and joined through the first flow path switching valve 3 are condensed in the non-use side heat exchanger 5 through the four-way valve 4. Is done. The condensed refrigerant adiabatically expands in the first expansion device 7 to be in a gas-liquid two-phase state, flows into the heat storage heat exchanger 11 of the heat storage device 8 from the inlet end 11A, and evaporates. At this time, heat exchange occurs with the heat storage medium 10 in the heat storage tank 9, and ice adheres concentrically to the heat transfer tubes of the heat storage heat exchanger 11. The evaporated refrigerant is the outlet end 11B
To the compressors 1 and 2 through the third flow path switching valve 12.

In order to explain the state of adhesion of ice on the heat storage device 8,
R22 as a single refrigerant and R407 as a non-azeotropic mixed refrigerant
FIG. 3 shows the relationship between the pressure loss in the heat transfer tube and the temperature difference between the inlet and outlet of the heat storage heat exchanger 11 when the refrigerant C is evaporated. When the pressure loss in the heat transfer tube is 0 (kg / cm ² ), the single refrigerant R
In No. 22, the inlet / outlet temperature difference is 0 ° C., whereas in the non-azeotropic refrigerant mixture R407C, the saturated liquid temperature has a characteristic lower than the saturated gas temperature.
About ℃ higher. Therefore, during the heat storage operation, the evaporating temperature increases along with the flow of the refrigerant, and the cooling capacity decreases, so that the thickness of the ice 10A attached to the heat transfer tube of the heat storage heat exchanger 11 is, as shown in FIG. It is thicker on the inflow side, that is, on the left side of the figure, and becomes gradually thinner along the flow.

Next, the cooling operation using heat storage will be described. The gas refrigerant discharged from the heat storage utilizing cooling compressor 2 flows into the heat storage heat exchanger 11 from the inlet end 11A via the fifth flow path switching valve 20, flows in the same direction as during the heat storage operation, and has the heat storage heat. It is condensed by ice adhering to the heat transfer tube of the exchanger 11. At this time, in the heat storage heat exchanger 11, the ice 10A attached to the heat transfer tube is concentrically melted, but the condensing temperature of the inlet end 11A, which is the inflow portion of the refrigerant, is higher than that of the outlet end 11B. As shown by a circle 10B without hatching, the amount of melting near the inlet end 11A is large, and the amount of melting decreases toward the outlet end 11B. That is, the amount of melting in the heat transfer tube with a thick icing is large, and the amount of melting in the heat transfer tube with a thin icing is small.

[0016]

The regenerative air conditioner according to the present invention has the following features.
Since the direction of the non-azeotropic mixed refrigerant flowing in the heat storage heat exchanger of the heat storage device is the same in both the heat storage operation and the heat storage cooling operation in the above-described configuration, the heat storage operation and the heat storage cooling operation are performed. Ice does not grow to the extent that ice blocks occur even after repeated ice and melting ice, and therefore there is no risk of damaging the heat transfer tubes of the heat storage device. In addition, when the blocking of ice occurs, the heat transfer area decreases and the operating efficiency deteriorates,
According to the present invention, such a problem does not occur.

[Brief description of the drawings]

FIG. 1 is a refrigerant circuit diagram showing a configuration of Embodiment 1 of the present invention.

FIG. 2 is a schematic diagram illustrating a state of ice adhering to a heat storage heat exchanger and melting ice of the heat storage device of the heat storage device according to the first embodiment.

FIG. 3 is a characteristic diagram showing a relationship between a pressure loss in a heat transfer tube and a temperature difference between an inlet and an outlet of a heat storage heat exchanger during evaporation of a single refrigerant and a non-azeotropic mixed refrigerant.

FIG. 4 is a refrigerant circuit diagram showing a configuration of a conventional heat storage type air conditioner.

FIG. 5 is a schematic diagram showing a state of ice attached to a heat storage heat exchanger in a conventional heat storage air conditioner.

FIG. 6 is a schematic diagram showing a melting state of ice attached to a heat storage heat exchanger in a conventional heat storage air conditioner.

FIG. 7 is a schematic diagram showing a state of ice adhering to a heat storage heat exchanger when a heat storage operation and a heat storage utilizing cooling operation are repeated in a conventional heat storage type air conditioner.

[Explanation of symbols]

1 Compressor, 2 Compressor for cooling using heat storage, 5
Non-use side heat exchanger, 7 first throttle device, 8 heat storage device, 10 heat storage medium, 11 heat storage heat exchanger,
14 2nd expansion device, 15 use side heat exchanger, 2nd 5th flow path switching valve, 21 6th flow path switching valve, 22 7th flow path switching valve.

Continued on the front page (72) Inventor Moriya Miyamoto 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation F-term (reference) 3L092 TA11 TA17 UA02 UA34 YA13

Claims (3)

[Claims] 1. A heat storage operation in which a non-azeotropic mixed refrigerant discharged from a compressor is condensed, adiabatically expanded, flows into a heat storage device having a heat storage medium and a heat storage heat exchanger, and adheres ice, and The non-azeotropic mixed refrigerant discharged from the compressor flows into the heat storage device after icing to condense, and the heat storage utilizing cooling operation in which the condensed refrigerant is adiabatically expanded and evaporated in the use side heat exchanger. Wherein the direction of the refrigerant flowing through the heat storage heat exchanger of the heat storage device is the same in both the heat storage operation and the heat storage cooling operation. Harmony equipment. 2. A compressor for compressing a non-azeotropic refrigerant mixture, a non-use side heat exchanger for condensing refrigerant discharged from the compressor, a throttle device for adiabatically expanding the condensed refrigerant, and an inlet to the throttle device. A heat storage device having a heat storage heat exchanger and a heat storage medium having ends connected thereto, a switching valve provided between an outlet end of the heat storage heat exchanger and a suction portion of the compressor, and opened only during a heat storage operation, A switching valve that is provided between the discharge part of the compressor and the inlet end of the heat storage heat exchanger and that opens only during the heat storage cooling operation, and that is provided between the outlet end of the heat storage heat exchanger and another throttle device. A regenerative air conditioner, comprising: a switching valve that opens only during a heat storage cooling operation; and a use side heat exchanger connected to the other expansion device. 3. The regenerative air conditioner according to claim 1, wherein the non-azeotropic mixed refrigerant is R407C.