13.74 Most architects know that the ceiling of an ice-skating rink must have a high reflectivity. Otherwise, condensationmay occur on the ceiling, and water may drip onto the ice, causing bumps on the skating surface. Condensation will occuron the ceiling when its surface temperature drops below the dew point of the rink air. Your assignment is to perform ananalysis to determine the effect of the ceiling emissivity on the ceiling temperature, and hence the propensity forcondensation.Outdoor airInsulation, k = 0.035 W/m K, thickness t= 0.3 mTopCeiling, T,E = 0.05 or 0.94Walls,Rink airT, = 15°CIce,Tice = -5°CThe rink has a diameter of D = 50 m and a height of L = 10 m, and the temperatures of the ice and walls are -5°C and 15°C,respectively. The rink air temperature is 15°C, and a convection coefficient of 5 W/m² . K characterizes conditions on theceiling surface. The thickness and thermal conductivity of the ceiling insulation are o.3 m and o.035 W/m · K, respectively,and the temperature of the outdoor air is -5°C. Assume that the ceiling is a diffuse-gray surface and that the walls and icemay be approximated as blackbodies.(a) Consider a flat ceiling having an emissivity of o.05 (highly reflective panels) or o.94 (painted panels). Perform anenergy balance on the ceiling to calculate the corresponding values of the ceiling temperature. If the relative humidity ofthe rink air is 70%, will condensation occur for either or both of the emissivities?(b) For each of the emissivities, calculate and plot the ceiling temperature as a function of the insulation thickness for 0.1stsim. Identify conditions for which condensation will occur on the ceiling.

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Answered: 13.74 Most architects know that the…

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

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2 parts ( C&D) Read and solve carefully please write clearly and box the final answer(s) label them Hint: Pay attention to numbers bolded
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A glass window pane and a pyrex window pane are held together as shown below. Heat is flowing through the combination from the hot side to the cold side. The temperatures of the hot surface and the cold surface are shown, with the temperature of the surface between them. The glass pane has a thickness of 3.00 mm. Find the thickness of the pyrex pane. (The cross-sectional areas are not needed.) Thermal conductivity of glass kglass = 0.800 J/s-m-C° Thermal conductivity of pyrex: kpyrex = 1.15 J/s-m-C° pyrex glass heat heat 3.00 mm T, = 38 °c T3 = 20° c %3D T2 = 23.4°C
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