JPH0120698B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-chamber cooling type refrigeration system in which a plurality of evaporators are connected in parallel.

In general, this type of refrigeration equipment is extremely popular because it can cool multiple rooms with a single compressor, but since the amount of refrigerant circulated differs between individual cooling operation and simultaneous cooling operation, the amount of circulation must be adjusted each time. Conventional methods for this purpose include using an expansion valve as a refrigerant pressure reducer for each evaporator to automatically adjust the refrigerant circulation amount according to each cooling load, or using a refrigerant pressure reducer to individually adjust the refrigerant circulation amount. A method using a capillary tube with a switching valve to adjust the temperature is adopted.

However, the former method has the disadvantage that the expansion valve is expensive and prone to failure, while the latter method requires individual switching valves, which increases manufacturing costs and requires automatic control of each switching valve. The drawback was that it required an electrical circuit and was complicated.

In view of this, it is an object of the present invention to provide a highly reliable refrigeration system that can adjust the refrigerant circulation amount to an appropriate amount during independent and simultaneous operation while suppressing cost increases. To,
The present invention connects a compressor, a condenser, a liquid receiver, a plurality of main on-off valves branch-connected in parallel, a main capillary tube and an evaporator each connected in series with the valves in an annular manner through a refrigerant pipe. A supercooler is attached to the refrigerant pipe between the liquid receiver and the branch connection point of the main on-off valve so as to exchange heat with this pipe, and the capacity of the evaporator operating at the refrigerant inlet end of the supercooler is The refrigerant outlet end of the supercooler is connected to the receiver through an auxiliary capillary and an auxiliary on-off valve that opens when the capacity is smaller than the set capacity and closes when the capacity is larger than the set capacity. .

With this configuration, when the capacity of the operating evaporator is larger than the set capacity, the resistance value of each main capillary tube whose refrigerant flow rate is set is adjusted so that the degree of superheating of the refrigerant in each evaporator is approximately uniform when the capacity of the operating evaporator is larger than the set capacity. When the capacity is lower than the set capacity, the high-pressure liquid refrigerant that has been gas-separated in the liquid receiver is forced into a supercooled liquid state by the supercooler to make a correction to a smaller value, so as to obtain the desired cooling capacity that is stable at all times.

Embodiments of the present invention will be described below based on the drawings. 1 is a compressor equivalent to 2 horsepower, 2 is a condenser equivalent to 2 horsepower that exchanges heat with outside air, 3 is a liquid receiver, 4a,
4b, 4c are main on-off valves connected in parallel to the bottom of the liquid receiver; 5a, 5b, 5c are main capillary tubes connected in series with these valves, respectively; 6a, 6b;
is an evaporator equivalent to 1 horsepower installed in each living room, 6
C is an evaporator equivalent to 2 horsepower installed in a store that also serves as a living room, and 7 is a gas-liquid separator.

In addition, 8 is the liquid receiver 3 and the main on-off valves 4a, 4b, 4c.
A subcooler is attached to the refrigerant pipe 14 between the branch connection point 9 and the refrigerant inlet end 10 to exchange heat with this pipe.
The refrigerant outlet end 13 is connected to the receiver 3 through the compressor 1.
The refrigerant is connected to the inlet side of the gas-liquid separator 7, which is the suction side of the refrigerant, and is configured to exchange heat while flowing from the opposite direction to the high-pressure refrigerant liquid flow of the refrigerant pipe 14.

Therefore, the resistance values of the main capillaries 5a, 5b, and 5c are set to be equal so that the degree of superheating of the refrigerant in each evaporator becomes approximately uniform when all the evaporators 6a, 6b, and 6c are operated simultaneously. The main capillary 5c is set smaller than both main capillaries. Further, the resistance value of the auxiliary capillary tube 12 is set to be smaller than that of the main capillary tube 5c.

Next, to explain the operation, the main on-off valves 4a, 4b,
4c is opened according to the operating evaporator 6a, 6b, 6c, and the auxiliary on-off valve 11 is opened according to the operating evaporator 6.
When the capacity of a, 6b, 6c is smaller than the set capacity,
That is, it is opened when the evaporators 6a and 6b are operating independently, when both are operating simultaneously, and when the evaporator 6c is operating independently, and when the capacity of the operating evaporators 6a, 6b, and 6c is larger than the set capacity, that is, the evaporator 6a is opened. ,6
It is designed to be closed when evaporators 6a, 6b, and 6c are operated simultaneously, and when evaporators 6a, 6b, and 6c are operated simultaneously.

That is, the operating capacity of the evaporators 6a, 6b, 6c is 2.
During heavy load operation of 3 horsepower or 4 horsepower, which exceeds the horsepower, the main capillary tubes 5a, 5b, and 5c adjust the pressure to an appropriate refrigerant circulation amount, and when operating with a small load of 2 horsepower or 1 horsepower, the main capillary tubes 5a, 5c, Since the resistance values of 5b and 5c are too large, in order to correct this, the high-pressure liquid refrigerant is led out from the liquid receiver 3 through the auxiliary on-off valve 11, the pressure is reduced in the auxiliary capillary tube 12, and the refrigerant is evaporated in the supercooler 8. By supercooling the high-pressure liquid refrigerant in the refrigerant pipe 14 with the latent heat of evaporation,
b, 5c, the generation of flash gas that causes resistance is suppressed to reduce the specific volume, thereby increasing the amount of refrigerant passing through, and adjusting the pressure reduction with an appropriate amount of circulation.

As described above, in a multi-room cooling type refrigeration system in which a plurality of evaporators are operated individually or simultaneously, when the capacity of the operating evaporator is larger than the set capacity, the auxiliary on-off valve is closed and the main capillary is operated properly. In addition to adjusting the pressure to the amount of refrigerant circulation, when the capacity of the evaporator being operated is smaller than the set capacity, the auxiliary on-off valve is opened to subcool the high-pressure liquid refrigerant that has been separated from the gas refrigerant in the liquid receiver using the subcooler. By suppressing the generation of flash gas, which causes resistance while passing through the main capillary tube, and increasing the amount of refrigerant passing through, the pressure reduction is adjusted based on the appropriate amount of refrigerant circulation, so even if the capacity of the evaporator being operated changes, the desired level of stability is maintained. cooling operation can be performed.

Furthermore, this can be achieved by a combination of an on-off valve and a capillary tube that are low cost and difficult to break down, and a highly reliable refrigeration system can be obtained while suppressing cost increase.

[Brief explanation of drawings]

The drawing is a refrigerant circuit diagram of a refrigeration system showing an embodiment of the present invention. 1...Compressor, 2...Condenser, 3...Liquid receiver,
4a, 4b, 4c...Main on-off valve, 5a, 5b, 5
c...main capillary, 6a, 6b, 6c...evaporator,
8... Supercooler, 9... Branch connection point, 10...
Refrigerant inlet end, 11... Auxiliary on-off valve, 12... Auxiliary capillary, 13... Refrigerant outlet end.

Claims (1)

[Claims] 1. A compressor, a condenser, a liquid receiver, a plurality of main on-off valves connected in parallel in parallel, a main capillary tube and an evaporator each connected in series with the valves are sequentially connected in an annular manner by a refrigerant pipe, and the receiver A supercooler is attached to the refrigerant pipe between the liquid container and the branch connection point of the main on-off valve to exchange heat with this pipe, and the capacity of the evaporator operating at the refrigerant inlet end of the supercooler is lower than the set capacity. A refrigeration system characterized in that the refrigerant outlet end of the supercooler is connected to the liquid receiver via an auxiliary on-off valve that opens when the liquid is small and closes when the liquid is large, and an auxiliary capillary tube, and to the suction side of the compressor.