High performance refrigerator having passive sublimation defrost of evaporator

摘要

A high performance refrigerator or freezer includes a cabinet with a refrigerated interior, a first evaporator cover separating a first evaporator compartment within the cabinet from the refrigerated interior, and a refrigeration fluid circuit having a first evaporator located within the first evaporator compartment, a second evaporator, and a three-way valve enabling selective communication of refrigerant to one or both of the evaporators. The second evaporator includes an air diffuser that receives chilled air from the first evaporator compartment and delivers the chilled air into the refrigerated interior. During normal operation, the three-way valve only directs refrigerant into the first evaporator such that the first evaporator cools the cabinet and the chilled air from the first evaporator passively defrosts the second evaporator by sublimation.