A localized area in an insulated structure where higher thermal conductivity materials create a pathway for accelerated heat transfer, bypassing surrounding insulation and causing concentrated thermal losses. In refrigerated vehicles,…
Thermal Load
The total heat energy that must be removed from a refrigerated space to achieve and maintain target temperature, comprising transmission loads through insulation, infiltration loads from air exchange, product loads…
Thermal Mass
The heat storage capacity of materials within a refrigerated space, determining how much thermal energy must be added or removed to change temperature. In frozen food transport, product thermal mass…
Thermal Resistance (R-value)
A measure of insulation effectiveness quantifying resistance to heat flow, expressed in m²·K/W (SI units) or ft²·°F·hr/BTU (imperial units). Higher R-values indicate better insulation performance – an R-5.0 insulation allows…
Thermal Stratification
The Physics of Stratification Air density varies with temperature—cold air at -18°C is approximately 15% denser than air at +20°C. This density difference creates buoyancy forces that cause cold air…
Thermal Stratification
Formation of horizontal temperature layers in refrigerated space, creating 8-15°C differences top-to-bottom – worsened by industry-standard evaporator designs that ignore warm ceiling air accumulation.
Timer-Based Defrost
Automatic defrost control system that activates on fixed time intervals regardless of actual ice accumulation, wasting 60% of defrost energy through inappropriate scheduling.
Total Cost of Ownership (TCO)
Complete lifecycle cost including purchase, fuel, maintenance, and product loss – proper analysis shows R25,000 premium equipment delivers R350,000 savings over 10 years versus cheap alternatives.
Transport Refrigeration Unit (TRU)
Self-contained refrigeration systems mounted on vehicles, trailers, or shipping containers, providing active temperature control independent of vehicle operation. TRUs include compressors, condensers, evaporators, controls, and power sources (typically diesel engines…
Urban Heat Island Effect
The measurable temperature elevation of urban areas compared to surrounding rural regions, caused by heat-absorbing surfaces (asphalt, concrete, buildings), reduced vegetation, waste heat from vehicles and air conditioning, and altered…