Definition: Heat exchanger where low-pressure liquid refrigerant absorbs heat from the cargo space and evaporates to vapor, providing cooling effect.
Types::
- **Forced-air**: Fans circulate air across coils (most common in TRUs and cold rooms)
- **Natural convection**: No fans, relies on air density differences (minimal use)
- **Plate evaporators**: Flat plates for direct contact (blast freezers)
Why It Matters: Evaporator sizing determines cooling capacity and temperature uniformity. Undersized evaporators cause poor temperature control and longer pull-down times.
Related Terms: Compressor, Condenser, Forced-Air Cooling, Thermal Load