A warehouse is to be designed for keeping perishable foods cool prior to transportation to grocery stores.

Question:

A warehouse is to be designed for keeping perishable foods cool prior to transportation to grocery stores. The warehouse has an effective surface area of 20,000 ft2 exposed to an ambient air temperature of 90?F. The warehouse wall insulation (k = 0.1 Btu/(h ft?F)) is 3 in. thick. Determine the rate at which heat must be removed (Btu/h) from the warehouse to maintain the food at 40?F.GIVENCooled warehouseEffective area (A) = 20,000 ft2TemperaturesOutside air = 90?F and food inside = 40?FThickness of wall insulation (L) = 3 in. = 0.25 ftThermal conductivity of insulation (k) = 0.1 Btu/(h ft?F)ASSUMPTIONSOne dimensional, steady state heat flowThe food and the air inside the warehouse are at the same temperatureThe thermal resistance of the wall is approximately equal to the thermal resistance of the wall insulationalone