A layer of pulverized cork 152-mm thick is used as a layer of thermal insulation in a flat wall. The temperature of the cold side of the cork is 4.4℃, and that of the warm side is 82.2℃. The thermal conductivity of the cork at 0 ℃ is 0.036 W/(m · ℃ ), and that at 93.3 ℃ is 0.055 W/(m · ℃ ). The area of the wall is 4.64 m2. What is the rate of heat flow through the wall in watts?

A cold-storage room is constructed of an inner layer of 11 mm of pine with thermal conductivity of 0.15 W/m K, and an outer layer of 75 mm of concrete with thermal conductivity of 0.75 W/m K. The  wall surface temperature is 253 K inside the cold room and 299 K at the outside surface of the concrete. Calculate the heat loss in W per 1 m2. Please keep one decimal and take positive value for the final answer.

An electronics device generates 37.5 W of heat energy during normal operation.  The heat is dissipated from the top surface of the device to ambient air at 21°C.  If the top surface area is 0.166 m2 and the convection heat transfer coefficient is 7.297 W/m2· K, what will be the surface temperature (in °C) of the device [round your final answer to one decimal place]?

A house has walls made out of steel with the following properties: Thickness 300 mm Density kg/m3 7800 Thermal Conductivity w/m-K 50 Specific Heat Capacity Embodied J/kg-K 500 MJ/kg 26 Energy Cost $/kg 0.70 The time that it will take, in hours, for the interior temperature to start changing after the exterior is exposed to a sudden temperature is:

A two-layer wall is made of two metal plates, with surface roughness of about 25 mm, pressed together at an average pressure of 10 MPa. The first layer is a stainless steel plate with a thickness of 5 mm and a thermal conductivity of 14 W/m∙K. The second layer is an aluminum plate with a thickness of 15 mm and a thermal conductivity of 237 W/m∙K. On the stainless steel side of the wall, the surface is subjected to a heat flux of 800 W/m2. On the aluminum side of the wall, the surface experiences convection heat transfer at an ambient temperature of 20°C, where the convection coefficient is 12 W/m2∙K. Determine the surface temperature of the stainless steel plate.

Consider a double-paned window consisting of two panes of glass, each with a thickness of 0.500 cm and an area of 0.795 m2 , separated by a layer of air with a thickness of 1.50 cm. The temperature on one side of the window is 0.00 ∘C∘C; the temperature on the other side is 21.0 ∘C∘C. In addition, note that the thermal conductivity of glass is roughly 36 times greater than that of air. Approximate the heat transfer through this window by ignoring the glass. That is, calculate the heat flow per second through 1.50 cmcm of air with a temperature difference of 21.0 ∘C∘C. (The exact result for the complete window is 25.6 J/sJ/s .)

A wall is constructed of a section of stainless steel [k = 16 W/m · °C] 4.0 mm thick with identical layers of plastic on both sides of the steel. The overall heat-transfer coefficient, considering convection on both sides of the plastic, is 120 W/m2 · °C. If the overall temperature difference across the arrangement is 60°C, calculate the temperature difference across the stainless steel.

A house, for cooling purposes, consists of two zones: the atric area zone A and the living area zone B (see below figure). The living area is cooled by a 2 -ton air conditioning unit that removes 23,000 Btu/hr. The heat capacity of zone B is 1/6 °F per thousand Btu. The time constant for heat transfer between zone A and the outside is 3ℎr, between zone B and the outside is 6ℎr, and between the two zones is 6ℎr. If the outside temperature stays at 90°F, how warm does it eventually get in the attic zone A ?

1.A carpenter builds an exterior house wall with a layer of wood 3.0 cm thick on the outside and a layer of Styrofoam insulation 2.2 cm thick on the inside wall surface. The wood has a thermal conductivity of 0.080 W/(m⋅K), and the Styrofoam has a thermal conductivity of 0.010 W/(m⋅K). The interior surface temperature is 19.0°C, and the exterior surface temperature is −10.0°C. (a) What is the temperature at the plane where the wood meets the Styrofoam? (b) What is the rate of heat flow per square meter through this wall?

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