Insulation Needed for Food Cold Storage Room. A food cold storage room is to be constructed of an inner layer of 19.1 mm of pine wood, a middle layer of cork board, and an outer layer of 50.8 mm of concrete. The inside wall surface temperature is -17.8°C and the outside surface temperature is 29.4°C at the outer concrete surface. The mean conductivities are for pine, 0.151; cork, 0.0433; and concrete, 0.762 w/m K. The total inside surface area of the room to use in the calculation is approximately 39m2 (neglecting corner and end effects). What thickness of cork board is needed to keep the heat loss to 586 W? 4.3-1. 4.3-2. Insulation of a Furnace. A wall of a furnace 0.244 m thick is constructed of material having a thermal conductivity of 1.30 W/m K. The wall will be insulated on the outside with material having an average k of 0.346 W/m K, so the heat loss from the furnace will be equal to or less than 1830 W/m?. The inner surface temperature is 1588 K and the outer 299 K. Calculate the thickness of insulation required.

Insulation Needed for Food Cold Storage Room. A food cold storage room is to be constructed of an inner layer of 19.1 mm of pine wood, a middle layer of cork board, and an outer layer of 50.8 mm of concrete. The inside wall surface temperature is – 17.8°C and the outside surface temperature is 29.4°C at the outer concrete surface. The mean conductivities are for pine, 0.151; cork, 0.0433; and concrete, 0.762 W/m K. The total inside surface area of the room to use in the calculation is approximately 39 m² (neglecting corner and end effects). What thickness of cork board is needed to keep the heat loss to 586 W? Ans. 0.128 m thickness

Heat transfer

A 50 mm diameter pipe of circular cross section and with walls 3 mm thick is covered with two concentric layers of lagging, the inner layer having a thickness of 25 mm and a thermal conductivity of 0.08 W/m-K, and the outer layer a thickness of 40mm and a thermal conductivity of 0.040 W/m-K. What is the rate of heat loss per metre length of pipe if the temperature inside the pipe is 550K and the outside surface temperature is 330K?A. 62.7 W/mB. 74.7 W/m C. 82.5 W/mD. 98.3 Wlm