The horizontal roof of a building has an emittance of 0.9. Air temperature is 1oC on a clear night. Sky acts as a black radiation sink at -60o If the underside of the roof is well insulated, estimate the roof temperature. Assume a convective heat transfer coefficient of 5 W/m2 K.

Q: After sunset, radiant energy can be sensed by a person standing near a brick wall. Such walls…

A: The radiant thermal flux per square metre from a brick wall at this temperature: 526.75 W/m2

Q: A solid sphere of radius R = 8.0 cm uniformly generates 5 × 10° W/m³ of heat within it. Surrounding…

A:

Q: A one-dimensional plane wall is exposed to convective and radiative conditions at x = 0. The ambient…

A: Given:The ambient temperature, T∞=20oC=20+273=293 KThe surrounding temperature, Tsur=40oC=40+273=313…

Q: A one-dimensional plane wall is exposed to convective and radiative conditions at x = 0. The ambient…

A: Given:The ambient temperature, T∞=20oC=20+273=293 KThe surrounding temperature, Tsur=40oC=40+273=313…

Q: Consider a small house with walls 3.7 m high and each of four walls is 12.2 m long. A total of eight…

A:

Q: A vertical plate is held at a constant temperature of 10oC. The surrounding air is at Tinf=100oC.…

A: When a vertical plate is held at a lower temperature than its surroundings, as in this case where…

Q: A 50-cm x 50-cm circuit board that contains 121 square chips on one side is to be cooled by combined…

A:

Q: A 25-cm circular grill has an emissivity of 0.9. If the temperature of the air and surrounding…

A:

Q: the outer surface temperature of the furnace should be kept below 45°C. Based on the above…

A:

Q: The horizontal roof of a building has an emittance of 0.9. Air temperature is 1oC on a clear night.…

A: Conduction and convection heat transfer needed the use of a material medium to transfer heat from…

Q: Coolant flowing through a radiator at the rate of 3 kg/s are cooled from 105 0C to 81 0 The specific…

A: Given data: Here is the given data, Coolant flow, m=3 kgs T1=105° and T2=81° Specific heat capacity,…

Q: A 1-m diameter spherical solid receives heat from a source at 160°C by radiation and transfers heat…

A: Given: Diameter of the solid sphere is 1 m. Source temperature is 160°C. Surrounding temperature is…

Q: Consider a silicon wafer positioned in a furnace that is zone-heated on the top section and cooled…

A: To find: The value of steady-state temperature of the wafer, in K. Given data: Tsur,h = 1150 KTsur,c…

Conduction and Convection

When energy travels from one object to another it is said to have undergone heat transfer. Heat transfer is nothing but the transfer of thermal energy or internal energy from one thing to another, like e.g., when a vessel with water, kept on top of a burner, heats up because of the flame underneath it.