The refrigeration system component where liquid refrigerant absorbs heat from cargo space, evaporating into gas and creating the cooling effect. Evaporators in transport refrigeration typically use fin-and-tube designs with fans forcing air circulation across cold coils. Proper evaporator sizing, airflow distribution, and defrost cycle management are critical for maintaining temperature uniformity throughout cargo space. Ice accumulation on evaporator coils reduces heat transfer efficiency, requiring periodic defrost cycles to restore performance. In multi-stop operations with frequent door openings introducing warm humid air, evaporators accumulate ice rapidly, making defrost cycle efficiency particularly important for fuel consumption and temperature stability. Most transport refrigeration systems mount evaporators on the interior ceiling, pulling air from below the unit rather than capturing warm air at the ceiling level where it naturally accumulates – a fundamental airflow physics error perpetuated throughout the industry.
Related Terms: Defrost Cycle, Transport Refrigeration Unit (TRU), Mechanical Refrigeration