Definition:Periodic process of removing ice buildup from evaporator coils. Ice accumulation reduces heat transfer efficiency and airflow.
Defrost Methods::
- **Off-cycle**: Simply turn off refrigeration, allowing ambient heat to melt ice (suitable for above-freezing applications)
- **Electric**: Use electric heating elements (common in TRUs)
- **Hot gas**: Reverse refrigerant flow to use hot compressor discharge gas (efficient, common in cold rooms)
- **Water**: Spray water over coils (industrial systems)
- Frozen applications: Every 4-8 hours
- Chilled applications: Every 8-24 hours or as needed
Why It Matters:: Inadequate defrost causes capacity loss, increased energy consumption, and potential temperature excursions. Humid coastal climates (Durban, Cape Town) require more frequent defrost than dry inland regions (Bloemfontein, Northern Cape).
Defrost Frequency::
Related Terms:: Evaporator, Frost Buildup, Temperature Cycling