Refrigeration compressor technology using variable-frequency drives or DC motors to modulate speed based on actual cooling demand, contrasting with traditional fixed-speed compressors that cycle on/off at maximum power. Variable-speed compressors reduce energy consumption 20-40% in applications with variable thermal loads by running at partial capacity during light loads rather than wasteful on/off cycling. Additional benefits include reduced mechanical wear from eliminating start/stop stress, tighter temperature control from continuous modulation, lower noise levels from partial-speed operation, and extended equipment life from reduced cycling. Variable-speed technology particularly benefits multi-stop delivery operations where thermal loads vary dramatically between recovery from door openings (requiring maximum capacity) and steady-state cruising (requiring minimal capacity). Yet the transport refrigeration industry continues installing fixed-speed compressors because they cost R2,000-3,000 less upfront, even though fuel savings recover the incremental cost within 12-18 months. This reflects supplier focus on initial sale price and fuel-dependent revenue rather than customer total cost of ownership.
Engineering Formula: For detailed variable-speed compressor ROI calculations including fuel savings and maintenance reduction analysis, see Variable Speed Compressor ROI in our Technical Formulas Reference.
Related Terms: Energy Efficiency (Cold Chain), Transport Refrigeration Unit (TRU), Coefficient of Performance (COP), Mechanical Refrigeration