How this calculator works
The cold room heat load calculator applies the five-component method from ASHRAE Handbook — Refrigeration 2022, Chapter 24: (1) transmission load through walls, floor, ceiling, and doors using the entered panel U-values; (2) infiltration load via the Gosney & Olama (1975) empirical ACH model adjusted for door width, height, and protection factor (Fm buoyancy correction by box temperature, strip-curtain Fprotection = 0.10, air-curtain Fprotection = 0.50); (3) product pull-down load from entered commodity, initial temperature, and pull-down period; (4) internal gains from lighting, motors, and occupants; (5) a 10 % safety factor. Ambient design temperatures for 12 Pakistan cities use ASHRAE 0.4 % design dry-bulb values with a +2 K climate uplift. Panel U-values are calculated from entered thickness and λ = 0.022 W/m·K (BS EN 14509 declared aged value for Izhar FireSafe PIR). Results are validated within ±20 % of Heatcraft NROES, Copeland AE-103, Danfoss Coolselector®2, and Bitzer Software for typical Pakistan cold-room geometries.
References: ASHRAE Refrigeration Handbook 2022 Ch. 24; Gosney & Olama (1975) Int. J. Refrigeration; BS EN 14509:2013; IEC 60335-2-89:2019.