The outside surface temperature of the door to a large industrial oven is measured to be 127.0°C. The air in the room has a temperature of 27.0°C at a pressure of 1.00 atm. The oven door has dimensions of 3.20 meters wide by 2.40 meters high. Calculate the heat transfer rate due to natural convection from the door; ignore radiation.

A thermopane window consists of two glass panes, each 0.50 cm thick, with a 1.0-cm-thick sealed layer of air in between. (a) If the inside surface temperature is 23.7°C and the outside surface temperature is 0.0°C, determine the rate of energy transfer through 1.70 m² of the window. 94.4 Your response is within 10% of the correct value. This may be due to roundoff error, or you could have a mistake in your calculation. Carry out all intermediate results to at least four-digit accuracy to minimize roundoff error. W (b) Compare your answer to (a) with the rate of energy transfer through 1.70 m² of a single 1.0-cm-thick pane of glass. Disregard surface air layers. (Find the rate of energy transfer.) 3.871 Your response differs from the correct answer by more than 10%. Double check your calculations. kW

Warm air flows through a rectangular, uninsulated heating duct in your cold attic during the winter. The air has a mass flow rate of 0.47 kg/sec, and the heating duct has dimensions of 20.0cm by 28.0cm with a length of L = 9.60m. The inlet temperature of the air is 42.0°C, at a pressure of 1.00 atm. Your cold attic keeps the surface temperature of the duct at a temperature of 8.0°C. Find the heat transfer rate.