JPWO2021192292A5

JPWO2021192292A5 -

Info

Publication number: JPWO2021192292A5
Application number: JP2022510390A
Authority: JP
Filing date: 2020-03-27
Publication date: 2022-09-29
Anticipated expiration: 2040-03-27

Claims

An outdoor unit of a refrigeration cycle apparatus configured to be connected to a load device including a first expansion valve and an evaporator,
a compressor having a suction port, a discharge port and an intermediate pressure port;
a condenser;
a heat exchanger having a first passage and a second passage, and performing heat exchange between the refrigerant flowing through the first passage and the refrigerant flowing through the second passage;
A flow path from the compressor to the condenser and the first passage of the heat exchanger forms a circulation flow path in which refrigerant circulates together with the load device,
further comprising an injection flow path for flowing a refrigerant to the compressor from a branch portion between the outlet of the condenser and the inlet of the first passage in the circulation flow path,
In the injection channel,
a first coolant channel that flows coolant from the branch portion to an inlet of the second channel;
a second refrigerant passage for flowing refrigerant from the outlet of the second passage to the suction port or the intermediate pressure port of the compressor;
a liquid receiver arranged in the first refrigerant flow path;
a third expansion valve arranged in a portion between the branch portion of the first refrigerant flow path and an inlet of the liquid receiver;
a flow control valve disposed in a portion of the first refrigerant flow path between the outlet of the liquid receiver and the inlet of the second passage,
a control device that controls the compressor , the third expansion valve, and the flow control valve;
Further comprising a notification device for notifying the user of information from the control device,
When the discharge pressure of the compressor is in a supercritical state exceeding the critical pressure of the refrigerant, the control device controls the refrigerant contained in the circulation flow path and the injection flow path based on the degree of opening of the flow control valve. An outdoor unit that determines whether or not there is a shortage of

In the supercritical state, the control device increases the degree of opening of the flow control valve as the difference between the discharge temperature of the compressor and the outside air temperature increases, so that the flow rate from the liquid receiver to the circulation flow path increases. increase the amount of refrigerant flowing to
When the control device is in the supercritical state and the state in which the opening degree of the flow control valve is the upper limit opening degree continues for a certain period of time, the refrigerant contained in the circulation flow path and the injection flow path 2. The outdoor unit according to claim 1, wherein it is determined that the is insufficient.

When the control device is not in the supercritical state and the temperature efficiency of the heat exchanger is less than the lower limit value, the controller determines that the refrigerant contained in the circulation flow path and the injection flow path is insufficient. The outdoor unit according to claim 2, wherein

In the non-supercritical state, the control device reduces the amount of refrigerant flowing from the liquid receiver to the circulation flow path by decreasing the degree of opening of the flow control valve as the temperature efficiency of the heat exchanger increases. let
When the state is not the supercritical state and the state in which the opening degree of the flow control valve is at the lower limit opening degree continues for a certain period of time, the control device controls that the refrigerant contained in the circulation flow path and the injection flow path is The outdoor unit according to claim 2 or 3, which is determined to be excessive.

5. The outdoor unit according to claim 3, wherein said control device calculates the temperature efficiency of said heat exchanger from a difference between an inlet temperature and an outlet temperature of said heat exchanger.

The controller determines that the liquid receiver is filled with liquid refrigerant and stops the compressor when the rate of decrease in the discharge temperature of the compressor is greater than a reference value. , The outdoor unit according to any one of claims 1 to 5.

The outdoor unit according to any one of claims 1 to 6, further comprising a second expansion valve arranged between said first passage of said heat exchanger and said load device in said circulation passage.

8. The outdoor unit according to claim 7 , wherein the control device adjusts the degree of opening of the second expansion valve so that the outlet pressure of the second expansion valve in the circulation passage does not exceed the design pressure of the load device. .

A refrigeration cycle apparatus comprising the outdoor unit according to any one of claims 1 to 8 and the load device.