The periodic process in refrigeration systems where heating elements melt ice accumulation on evaporator coils to maintain cooling efficiency. Traditional timer-based defrost cycles activate at fixed intervals regardless of actual ice buildup, wasting significant energy by heating components that don’t require defrosting. This inefficiency is particularly problematic in South African courier operations with frequent door openings and variable humidity conditions. Modern demand-based defrost systems use sensors to detect actual ice formation, reducing energy consumption by 20-30% compared to timer-based systems. The choice between timer and intelligent defrost directly impacts fuel costs, equipment wear, and operational efficiency – yet most transport refrigeration units still use 1980s-era timer technology because it benefits TRU manufacturers through increased fuel consumption and maintenance revenue.
Engineering Formula: For quantified energy waste calculations and ROI analysis of demand-based defrost systems, see Defrost Cycle Energy Waste in our Technical Formulas Reference.
Related Terms: Transport Refrigeration Unit (TRU), Energy Efficiency (Cold Chain), Evaporator
Related Articles: The Defrost Cycle Dictatorship