Refrigeration system with direct expansion refrigeration mode and refrigerant pumping energy-efficiency mode and control method of refrigeration system

A refrigeration system with a direct expansion refrigeration mode and a refrigerant pumping energy-efficiency mode comprising a cooling circuit including a compressor, an evaporator assembly, and a condenser assembly sequentially arranged on the cooling circuit, the refrigeration system further comprising:

• a liquid pump cooling assembly arranged on the cooling circuit and located between the condenser assembly and the evaporator assembly, wherein the liquid pump cooling assembly comprises:
• a housing and a liquid pump arranged in the housing, the housing defining a cavity that has a liquid reserving function;
• a refrigerant inlet communicating with the cavity;
• a first outlet connected to the cavity;
• and
• a second outlet connected to the liquid pump;
• wherein an outlet of the condenser assembly is connected with the refrigerant inlet, and both the first outlet and second outlet are connected with an inlet of the evaporator assembly;
• and
• a control assembly, wherein the compressor and the liquid pump are respectively connected with the control assembly to enable the refrigeration system to have a direct expansion refrigeration mode and a refrigerant pumping energy-efficiency mode;
• wherein in the direct expansion refrigeration mode the compressor is in an open state and compresses refrigerant that is in a vapor phase and the liquid pump is in a closed state, such that refrigerant flowing out from the outlet of the condenser assembly enters into the evaporator assembly after sequentially passing through the refrigerant inlet and the first outlet so as to enable refrigerant to circulate in the cooling circuit by the compressor;
• and
• in the refrigerant pumping energy-efficiency mode the liquid pump is in an open state and pumps refrigerant in a liquid state and the compressor is in a closed state, such that under an effect of the liquid pump, refrigerant flowing out from the outlet of the condenser assembly flows out from the second outlet and enters the evaporator assembly.