A long pipe 5 cm in diameter passes through a room and is exposed to air at atmospheric pressure and temperature of 20.C. The pipe surface temperature is 93°C Assuming that the emissivity of the pipe is 0.6 calculate the radiation heat loss per meter of length of pipe

2. A heater is a thin vertical panel 1.0m long and 0.7m high and is used in a warehouse to keep workers warm. The heater has air circulating on each side. Assume the maximum temperature of the panel is 60°C (already above the board line that is safe for human hands to touch briefly without getting hurt). Assume the room air temperature is 18°C but the warehouse wall temperature is 5°C. Model the surface with an emittance of 0.9 and Vair = 1.57x105 m²/s. a. Determine the maximum power rating for the heater. b. Now if you run the heat by standing on its side (it will be 1.0 m high and 0.7 m long), determine the surface temperature. c. Compare case a and b and explain any differences you see.

A one-dimensional plane wall is exposed to convective and radiative conditions at x = 0. The ambient and surrounding temperatures are T. exposed surface is a = 0.78. Determine the convective and radiative heat fluxes to the wall at x = 0, both in W/m2, if the wall surface = 20°C and Tsur = 40°C, respectively. The convection heat transfer coefficient is h = 20 W/m²-K, and the absorptivity of the temperature is T, = 30°C. Assume the exposed wall surface is gray, and the surroundings are large. gbonv i W/m? Tad i W/m2