Abstract: Provided is a heat transfer composition, which is characterized in that the heat transfer composition comprises the following three components: 1,1,1,2-tetrafluoroethane (R134a) with a mass ratio of 28%-46%, 2,3,3,3-tetrafluoropropene (R1234yf) with a mass ratio of 33%-71%, and trans 1,3,3,3-tetrafluoropropene (R1234ze(E)) with a mass ratio of I %-23%. The described heat transfer composition which replaces R134a not only has the environmentally friendly features of having low GWP and zero ODP, but also has excellent thermal performance. When applied in a centrifugal chiller, the volumetric refrigeration capacity and energy efficiency are equivalent to those of a centrifugal unit using an R134a refrigerant, and the slip in temperature is small; thus, the present application may become a heat transfer composition to replace R134a.

Abstract: Provided are a gas-replenishing and enthalpy-increasing control method, device and apparatus for a two-stage compressor. The method includes: when a gas-replenishing electronic expansion valve needs to be opened, gradually increasing, by a controller, an opening degree of the gas-replenishing electronic expansion valve in a time sequence; after the gas-replenishing electronic expansion valve is opened, acquiring a detected gas-replenishing superheat degree of a two-stage compressor; and adjusting, based on the gas-replenishing superheat degree of the two-stage compressor, the opening degree of the gas-replenishing electronic expansion valve, wherein the gas-replenishing electronic expansion valve is disposed between a medium-pressure liquid storage tank and the two-stage compressor, and when the opening degree of the gas-replenishing electronic expansion valve is not zero, a gaseous refrigerant in the medium-pressure liquid storage tank replenishes gas and increases enthalpy for the two-stage compressor.

Abstract: Provided herein is a compression system including a compressor, an intermediate air compensation pipeline, and an air compensation valve disposed on the intermediate air compensation pipeline. According to a flow direction of a refrigerant, a first pressure detection device and a first temperature detection device are disposed at the inlet end of the air compensation valve on the intermediate air compensation pipeline; a second temperature detection device is disposed at the outlet end of the air compensation valve. The system also includes a second pressure detection device and a third temperature detection device disposed on an exhaust pipeline of the compressor.

Abstract: Described is a two-stage compression air conditioning system and a method of controlling gas replenishment thereof. The two-stage compression air conditioning system includes a two-stage compressor and a flash evaporator, wherein a first port of the flash evaporator is connected to one end of a stop valve by a first pipeline and the other end of the stop valve is connected to a first gas intake of the two-stage compressor by a second pipeline. The method of controlling gas replenishment includes: obtaining a first temperature value and an intermediate pressure value in the first pipeline, and a second temperature value in the second pipeline; and controlling the stop valve according to the first temperature value, the intermediate pressure value and the second temperature value.

Abstract: The present disclosure provides a variable-capacity compressor, a variable-capacity two-stage compression system and a control method thereof. The compression system includes a compressor, wherein the compressor includes a low pressure cylinder and a high pressure cylinder connected in series, wherein the low pressure cylinder includes at least two cylinders connected in parallel. The compression system further includes a control mechanism that can control at least one of the at least two cylinders connected in parallel to perform full-load and/or no-load operation.

Abstract: Provided herein is a compression system including a compressor, an intermediate air compensation pipeline, and an air compensation valve disposed on the intermediate air compensation pipeline. According to a flow direction of a refrigerant, a first pressure detection device and a first temperature detection device are disposed at the inlet end of the air compensation valve on the intermediate air compensation pipeline; a second temperature detection device is disposed at the outlet end of the air compensation valve. The system also includes a second pressure detection device and a third temperature detection device disposed on an exhaust pipeline of the compressor.

Abstract: Provided are a gas-replenishing and enthalpy-increasing control method, device and apparatus for a two-stage compressor. The method includes: when a gas-replenishing electronic expansion valve needs to be opened, gradually increasing, by a controller, an opening degree of the gas-replenishing electronic expansion valve in a time sequence; after the gas-replenishing electronic expansion valve is opened, acquiring a detected gas-replenishing superheat degree of a two-stage compressor; and adjusting, based on the gas-replenishing superheat degree of the two-stage compressor, the opening degree of the gas-replenishing electronic expansion valve, wherein the gas-replenishing electronic expansion valve is disposed between a medium-pressure liquid storage tank and the two-stage compressor, and when the opening degree of the gas-replenishing electronic expansion valve is not zero, a gaseous refrigerant in the medium-pressure liquid storage tank replenishes gas and increases enthalpy for the two-stage compressor,.

Abstract: Described is a two-stage compression air conditioning system and a method of controlling gas replenishment thereof. The two-stage compression air conditioning system includes a two-stage compressor and a flash evaporator, wherein a first port of the flash evaporator is connected to one end of a stop valve by a first pipeline and the other end of the stop valve is connected to a first gas intake of the two-stage compressor by a second pipeline. The method of controlling gas replenishment includes: obtaining a first temperature value and an intermediate pressure value in the first pipeline, and a second temperature value in the second pipeline; and controlling the stop valve according to the first temperature value, the intermediate pressure value and the second temperature value.

Abstract: The present disclosure provides a variable-capacity compressor, a variable-capacity two-stage compression system and a control method thereof. The compression system includes a compressor, wherein the compressor includes a low pressure cylinder and a high pressure cylinder connected in series, wherein the low pressure cylinder comprises at least two cylinders connected in parallel. The compression system further comprises a control mechanism that can control at least one of the at least two cylinders connected in parallel to perform full-load and/or no-load operation.