Hot Gas Defrost Using a Work Recovery Device

A refrigeration system, comprising a gas cooler, a flash tank, a work recovery device located downstream from the gas cooler, a first evaporator unit located downstream from an outlet of the work recovery device, and a controller communicatively coupled to the work recovery device, wherein:

• the flash tank is configured to store refrigerant;
• the gas cooler is configured to receive the refrigerant and facilitate heat transfer from the received refrigerant, thereby cooling the refrigerant;
• the controller is configured to:
• determine whether defrost of an evaporator of the first evaporator unit is needed;
• in response to determining that defrosting of the evaporator of the first evaporator unit is needed:
• turn on the work recovery device;
• cause the work recovery device, while turned on, to:
• receive, at an inlet, a flow of refrigerant from at least one of the flash tank or an evaporator unit that is operated in a refrigeration mode;
• increase a pressure of the flow of refrigerant;
• and
• provide, from the outlet, the flow of refrigerant to the first evaporator unit thereby defrosting the evaporator of the first evaporator unit;
• wherein the work recovery device comprises a compressor.