A 10 ft length of pipe with an inner radius of 1 in and outer radius of 1.25 in has an outer surface temperature of 250 F. The heat transfer rate is 30,000 BTU/hr. Find the interior surface temperature. Assume k = 25 BTU/hr-ft-F.

The wall of a furnace has an inner temperature of 500 F. The wall has a thickness of 2 inches and has a thermal conductivity of 0.02 Btu/(h·ft·F). On the outside, air at 30 F flows over the 10 ft x 10 ft wall at a speed of 10 ft/s. Determine the rate of heat loss from the furnace to the environment. Use thermal resistance to solve

A wood stove heats a small cabin with the following dimensions 8 m x 6 m x 3 m (length x width x height) to 25°C. Of the heat generated by burning wood, 60% is lost up the chimney. The cabin also loses heat through walls, ceiling and floor. Assume that all sides of the house except the floor are insulated with a 10 cm thick polyethylene foam layer having a thermal conductivity htc = 0.038 W/(m•°C). The heat loss through the floor is 1/5 of the heat loss through the ceiling. Outside air is at -5°C. a) How much heat is lost in total from the ceiling, walls, and floor? b) How many kg of wood per hour is needed as fuel for the cabin to maintain its temperature if heat value of wood is AH = 18,000 kJ/kg?

= 31. A circular fin of diameter D = 0.25 inches and length L 4 inches transfers heat at a rate Q = 5.66 Btu/hr to air. The convective heat transfer coefficient is 3.62 Btu/hr-ft²- °F and the temperature difference between the fin-wall interface and the air is 100 °F. What is the thermal conductivity of the fin? What is the temperature of the fin tip?