Self-powered transport refrigeration system with dedicated diesel engine driving compressor. Most common type of TRU for long-haul refrigerated transport.
Direct Drive TRU
Transport refrigeration unit powered directly by the vehicle’s main engine via a mechanically-driven compressor (PTO – Power Take-Off). No separate refrigeration engine.
Dry Ice
Solid carbon dioxide (COā) at -78.5Ā°C, used as non-mechanical refrigerant for shipping and emergency cooling.
Dwell Time
The time product remains at a specific location (warehouse, terminal, dock) before moving to next stage of supply chain.
EHP (Environmental Health Practitioner)
Professionally registered health practitioner qualified to inspect food facilities, assess R638 compliance, and issue compliance reports. Registration with Health Professions Council of South Africa (HPCSA) required.
Electric TRU (e-TRU)
Transport refrigeration unit powered by electricity instead of diesel engine. Power source can be vehicle batteries, shore power, or dedicated refrigeration batteries.
Enthalpy
Total heat content of a refrigerant, including both sensible heat (temperature change) and latent heat (phase change). Measured in kJ/kg (kilojoules per kilogram).
Eutectic System
Passive cooling system using phase-change materials (eutectic plates) that freeze overnight and provide cooling during operation through controlled melting.
Evaporative Cooler (Swamp Cooler)
Cooling system that uses water evaporation to lower air temperature. Not true refrigeration; cannot achieve temperatures below ambient wet-bulb temperature.
Evaporator
Heat exchanger where low-pressure liquid refrigerant absorbs heat from the cargo space and evaporates to vapor, providing cooling effect.