Refrigerating cycle apparatus having an injection circuit and operating with refrigerant in supercritical state

摘要

A refrigeration cycle apparatus increases the cooling capacity even under overload conditions in a refrigeration cycle apparatus that uses a refrigerant which undergoes transition to a supercritical state and in which the high-pressure side enters a supercritical state.;A refrigeration cycle apparatus adjusts a high-pressure-side pressure of a refrigerant flowing through a main refrigerant circuit by causing a controller to control an opening degree of a second expansion valve and a heat transfer area of a radiator.

主权项

1. A refrigeration cycle apparatus comprising:
a main refrigerant circuit in which a compressor that compresses a refrigerant, a radiator that rejects heat of the refrigerant compressed by the compressor, a primary passage of an internal heat exchanger that exchanges heat between the refrigerant which has passed through the radiator and refrigerant which has passed through the radiator and is to be injected into the compressor, a first pressure reducing device that reduces a pressure of the refrigerant which has passed through the primary passage of the internal heat exchanger, and an evaporator where the refrigerant that has been subjected to pressure reduction by the first pressure reducing device evaporates are sequentially connected to one another by pipes; an injection circuit in which a second pressure reducing device that reduces a pressure of the refrigerant which has passed through the radiator and is to be injected into the compressor, a secondary passage of the internal heat exchanger, and an injection port of the compressor are sequentially connected to one another by pipes; and a controller that controls an opening degree of the second pressure reducing device and a heat transfer area of the radiator, wherein the high-pressure-side pressure of the refrigerant flowing through the main refrigerant circuit enters a supercritical state, and the controller simultaneously adjusts the opening degree of the second pressure reducing device and reduces the heat transfer area of the radiator so as to increase a high-pressure-side pressure if the operation state is under an overload condition in which both outside and inside air temperatures are high enough to be indicative of overloading.