A refrigeration system, wherein the refrigeration system comprises: - refrigeration system components, comprising a compressor (101; 617), a first heat exchanger (102; 603), a second heat exchanger (112; 604), a third heat exchanger (113; 615), a first throttle valve (108; 609) and a second throttle valve (105; 612); - connecting pipelines, capable of connecting all of the abovementioned refrigeration system components, and capable of combining the refrigeration system components in different ways to form multiple different operating systems; - a switch structure, configured to be capable of connecting the connecting pipelines to form one operating system, and capable of selecting, from the first heat exchanger (102; 603), the second heat exchanger (112; 604) and the third heat exchanger (113; 615), two heat exchangers for connection into said one operating system, and isolating a non-selected heat exchanger from said one operating system; - a discharge path (123, 124; 623, 624), the discharge path (123, 124; 623, 624) being arranged between the non-selected heat exchanger and a low-pressure side of said one operating system, and capable of controllably connecting the non-selected heat exchanger to the low-pressure side of said one operating system, the discharge path (123, 124; 623, 624) comprising a discharge switch device for controlling the connection and disconnection of the discharge path (123, 124; 623, 624); - a control device (144; 644), the control device (144; 644) being in communicative connection with the discharge switch device, wherein the control device is configured to connect the discharge path between the non-selected heat exchanger and the low-pressure side (C; Q) of said one operating system when the temperature of a medium, which undergoes heat transfer with a refrigerant, in the non-selected heat exchanger or the temperature of an environment in which the non-selected heat exchanger is located is lower than a saturation temperature of refrigerant in the non-selected heat exchanger. - refrigeration system components, comprising a compressor (101; 617), a first heat exchanger (102; 603), a second heat exchanger (112; 604), a third heat exchanger (113; 615), a first throttle valve (108; 609) and a second throttle valve (105; 612); - connecting pipelines, capable of connecting all of the abovementioned refrigeration system components, and capable of combining the refrigeration system components in different ways to form multiple different operating systems; - a switch structure, configured to be capable of connecting the connecting pipelines to form one operating system, and capable of selecting, from the first heat exchanger (102; 603), the second heat exchanger (112; 604) and the third heat exchanger (113; 615), two heat exchangers for connection into said one operating system, and isolating a non-selected heat exchanger from said one operating system; - a discharge path (123, 124; 623, 624), the discharge path (123, 124; 623, 624) being arranged between the non-selected heat exchanger and a low-pressure side of said one operating system, and capable of controllably connecting the non-selected heat exchanger to the low-pressure side of said one operating system, the discharge path (123, 124; 623, 624) comprising a discharge switch device for controlling the connection and disconnection of the discharge path (123, 124; 623, 624); - a control device (144; 644), the control device (144; 644) being in communicative connection with the discharge switch device, wherein the control device is configured to connect the discharge path between the non-selected heat exchanger and the low-pressure side (C; Q) of said one operating system when the temperature of a medium, which undergoes heat transfer with a refrigerant, in the non-selected heat exchanger or the temperature of an environment in which the non-selected heat exchanger is located is lower than a saturation temperature of refrigerant in the non-selected heat exchanger.