Consider a room of dimensions (3 x 3 x 2.7 m) that is exposed to the outdoors on one side only. The external wall (e, = 15 cm, pe = 2400kg/m³, k = 1.3 W /m - K) is subjected to solar radiation flux of 800 W/m and a convective heat flux with the ambient air at 36 °C with a transfer coefficient of 10 W/m²-K. The inner side of the extemal wall is exposed to the room air to which heat is transferred by convection with a coefficient of 7.5 W/m²-K. The room is supplied by an airstream of air at 15 °C and flowrate of 0.05 kg/s. Using the nodal method (take 5 nodes), write the necessary equations and assemble the matrix (without solving it) needed to determine the temperature distribution inside the external wall, assuming that the other walls of the room are adiabatic. m = 0.05 kg/s T = 15°C Solar radiation S = 800 W/m? h = 10 W/m?. T= 36 °C h= 7.5 W /m2 K T Tin m = 0.05 kg/s T= Tin

Consider a room of dimensions (3 x 3 x 2.7 m) that is exposed to the outdoors on one side only. The external wall (e, = 15 cm, pe = 2400kg/m³, k = 1.3 W /m - K) is subjected to solar radiation flux of 800 W/m and a convective heat flux with the ambient air at 36 °C with a transfer coefficient of 10 W/m²-K. The inner side of the extemal wall is exposed to the room air to which heat is transferred by convection with a coefficient of 7.5 W/m²-K. The room is supplied by an airstream of air at 15 °C and flowrate of 0.05 kg/s. Using the nodal method (take 5 nodes), write the necessary equations and assemble the matrix (without solving it) needed to determine the temperature distribution inside the external wall, assuming that the other walls of the room are adiabatic. m = 0.05 kg/s T = 15°C Solar radiation S = 800 W/m? h = 10 W/m?. T= 36 °C h= 7.5 W /m2 K T Tin m = 0.05 kg/s T= Tin

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter2: Steady Heat Conduction

Section: Chapter Questions

Problem 2.9P: 2.9 In a large chemical factory, hot gases at 2273 K are cooled by a liquid at 373 K with gas-side...

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3.16 A large, 2.54-cm.-thick copper plate is placed between two air streams. The heat transfer coefficient on one side is and on the other side is . If the temperature of both streams is suddenly changed from 38°C to 93°C, determine how long it takes for the copper plate to reach a temperature of 82°C.
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2.38 The addition of aluminum fins has been suggested to increase the rate of heat dissipation from one side of an electronic device 1 m wide and 1 m tall. The fins are to be rectangular in cross section, 2.5 cm long and 0.25 cm thick, as shown in the figure. There are to be 100 fins per meter. The convection heat transfer coefficient, both for the wall and the fins, is estimated to be K. With this information determine the percent increase in the rate of heat transfer of the finned wall compared to the bare wall.
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