Freezing apparatus

Abstract

An object is to inhibit disproportionation reactions that may occur while a refrigerant having a low GWP is used. A freezing apparatus of the present disclosure includes: a compressor, a condenser, an expansion mechanism, and an evaporator. In the freezing apparatus, a working medium containing an ethylene-based fluoroolefin is used as a refrigerant. The compressor includes a suction part that sucks in the working medium, a compression mechanism that compresses the working medium sucked through the suction part, and a refrigerant supply part that supplies the working medium to the compression mechanism via a path different from the suction part. The compressor is an internal low pressure compressor in which the compression mechanism, together with an electric motor, is accommodated in a container, so that the compression mechanism sucks and compresses the working medium present in the container.

1 . A freezing apparatus comprising a compressor, a condenser, an expansion mechanism, and an evaporator, wherein
 a working medium containing an ethylene-based fluoroolefin is used as a refrigerant,   the compressor includes a suction part that sucks in the working medium, a compression mechanism that compresses the working medium sucked through the suction part, and a refrigerant supply part that supplies the working medium to the compression mechanism via a path different from the suction part, and   the compressor is an internal low pressure compressor in which the compression mechanism, together with an electric motor, is accommodated in a container, so that the compression mechanism sucks and compresses the working medium present in the container.   
     
     
         2 . The freezing apparatus according to  claim 1 , comprising:
 a refrigerant storage part provided between the condenser and the evaporator; and   a refrigerant pipe that delivers the working medium as a gas from the refrigerant storage part to the refrigerant supply part, wherein   the expansion mechanism structures a two-stage expansion process including an expansion valve that is positioned at an exit of the condenser and operates as a first-stage decompression mechanism, and the refrigerant storage part.   
     
     
         3 . A freezing apparatus comprising a compressor, a condenser, an expansion mechanism, and an evaporator, wherein
 a working medium containing an ethylene-based fluoroolefin is used as a refrigerant,   the compressor is a two-stage compressor including a suction part that sucks in the working medium, a first compression mechanism that compresses the working medium sucked through the suction part, and a second compression mechanism that compresses the working medium compressed by the first compression mechanism, and   the compressor has a refrigerant supply part that supplies the working medium to a position between the first compression mechanism and the second compression mechanism.   
     
     
         4 . The freezing apparatus according to  claim 1 , comprising:
 an electric motor cooling circuit that causes the working medium as a liquid to flow into a suction pipe or the container of the compressor;   an electric motor cooling valve that opens and closes the electric motor cooling circuit; and   a control device that controls the electric motor cooling valve, wherein   when a temperature of the compressor satisfies a condition set in advance, the control device exercises control so as to open the electric motor cooling valve.   
     
     
         5 . The freezing apparatus according to  claim 1 , wherein
 a discharge pipe through which the compressor discharges compressed refrigerant is provided with pressure releasing means that releases pressure when pressure of the discharge pipe is equal to or higher than a set pressure value.   
     
     
         6 . The freezing apparatus according to  claim 1 , wherein
 the expansion mechanism includes an expansion valve positioned at an exit of the condenser,   the freezing apparatus comprises a control device that controls the expansion valve, and   upon detecting that pressure of the working medium in a high pressure part including the compressor and the condenser has increased to a threshold value or higher, the control device causes the expansion valve to operate in a closing direction to a first opening degree, and subsequently, when the pressure increase of the working medium in the high pressure part has stopped, causes the expansion valve to operate in the closing direction to a second opening degree.   
     
     
         7 . The freezing apparatus according to  claim 6 , comprising:
 a heat source-side heat exchanger;   a use-side heat exchanger; and   a switching valve that switches between a heating operation state in which the use-side heat exchanger is caused to operate as the condenser and a cooling operation state in which the heat source-side heat exchanger is caused to operate as the condenser, wherein   upon detecting, in the heating operation state, that pressure of the working medium in the high pressure part including the compressor and the condenser has increased to a threshold value or higher, the control device controls the switching valve so as to switch operation from the heating operation state to the cooling operation state.   
     
     
         8 . The freezing apparatus according to  claim 7 , wherein
 the switching valve is configured by using a four-way valve or an electromagnetic open/close valve that operates on low differential pressure.