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Unformatted text preview: Problem 4 You would like to put a solar hot water system on your roof, but you’re not sure it’s feasible. A reference book on solar energy shows that the ground-level solar intensity in your city is 800 W / m 2 for at least 5 hours a day throughout most of the year. Assuming that a completely black collector plate loses energy only by radiation, and that the air temperature is 20 ◦ C, what is the equilibrium temperature of a collector plate directly facing the sun? Note that while a plate has two sides, only the side facing the sun will radiate because the opposite side will be well insulated. 1 - 1 Problem 5 A cubical box 20 cm on a side is constructed from 1 . 2 cm thick concrete panels. A 100 W lightbulb is sealed inside the box. What is the air temperature inside the box when the light is on if the surrounding air temperature is 20 ◦ C? 1 - 2...
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This note was uploaded on 04/26/2009 for the course PHYS 153 taught by Professor Measday during the Winter '08 term at The University of British Columbia.
- Winter '08