Thermodynamics HW Solutions 970

Thermodynamics HW Solutions 970 - Chapter 12 Radiation Heat...

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Chapter 12 Radiation Heat Transfer 12-87 A car mechanic is working in a shop heated by radiant heaters in winter. The lowest ambient temperature the worker can work in comfortably is to be determined. Assumptions 1 The air motion in the room is negligible, and the mechanic is standing. 2 The average clothing and exposed skin temperature of the mechanic is 33 ° C. Properties The emissivity and absorptivity of the person is given to be 0.95. The convection heat transfer coefficient from a standing body in still air or air moving with a velocity under 0.2 m/s is h conv = 4.0 W/m 2 ⋅° C (Table 12-3). Analysis The equivalent thermal resistance of clothing is R cloth 22 clo m . C / W = 0.1085 m . C / W == × ° ° 07 07 0155 .. . Radiation from the heaters incident on the person and the rate of sensible heat generation by the person are
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This note was uploaded on 01/24/2012 for the course PHY 4803 taught by Professor Dr.danielarenas during the Fall '10 term at UNF.

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