Refrigeration cycle apparatus

Abstract

A refrigeration cycle apparatus has a refrigerant circuit A. The refrigerant circuit A comprises a compressor 11, a refrigerant passage 12a of a radiator 12 as a water heating heat exchanger, a high pressure side refrigerant passage 15a of internal heat exchanging means 15, a decompressor 13, an evaporator 14, and a low pressure side refrigerant passage 15b of the internal heat exchanging means 15. In the refrigeration cycle apparatus, a pressure detecting apparatus 24 detects that a high pressure side pressure rises to about design pressure, a first solenoid valve 17 provided in a bypass circuit 16 is controlled, by a solenoid valve control apparatus 25, so as to be closed, a low pressure side refrigerant is allowed to flow into the low pressure side refrigerant passage 15b between an outlet of the evaporator 14 and an inlet of the compressor 11, a high pressure side refrigerant flowing through the high pressure side refrigerant passage 15a between an outlet of the radiator 12 and an inlet of the decompressor 13 is cooled, thereby reducing a high pressure side pressure.

Description

technical field [0001] The present invention relates to an apparatus as a refrigerant refrigerating cycle using a refrigerant capable of being in a supercritical state on a high-pressure side. Background technique [0002] Conventionally, hydrocarbons containing fluorine atoms (Freons) have been used as refrigerants to be enclosed in refrigeration cycle apparatuses. However, Freon has the property of depleting the ozone layer and has a long lifetime in the atmosphere, so that it has a large greenhouse effect, and therefore affects global warming, so it cannot be said to be a satisfactory refrigerant. Therefore, it has been proposed to use carbon dioxide, ethane, etc. as refrigerants instead of Freon-based refrigeration cycle devices (for example, refer to Patent Document 1). The ozone destruction coefficient of carbon dioxide, ethane, etc. is zero, and the global warming coefficient is comparable to that of Freon. is also very small. [0003] Refrigerants such as carbon di...

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Problems solved by technology

[0009] For this reason, various investigations have been carried out on refrigeration cycle equipment without storage tanks or accumulators. As a result, it has been found that in normal operating conditions, by adjusting the opening of the pressure reducer, the holding capacity of the low-pressure side is equal to that of the high-pressure side. The ratio of the holding volume is changed, so that the pressure on the high-pressure side can be adjusted to some extent, but in the case of the fluid radiated by the radiator (such as indoor air and outside air in the case of an air conditioner, and in the case of a hot water supplier, etc. When the temperature of the high-pressure side is high, there is a problem that the reliability of the refrigeration cycle device will decrease due to an abnormal increase in the pressure of the high-pressure side

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