Consider a person standing in a room maintained at 20 o C at all times. The inner surfaces of the walls, floors, and ceiling of the house are observed to be at an average temperature of 12 o C in winter and 23 o C in summer. Determine the rates of radiation heat transfer between this person and the surrounding surfaces in both summer and winter if the exposed surface area, emissivity, and the average outer surface temperature of the person are 1.6 m 2 , 0.95 , and 32 o C, respectively.
Solution Summary: The author calculates the rate of radiation heat transfer between the person and surrounding room surface in summer and winter.
Consider a person standing in a room maintained at
20
o
C
at all times. The inner surfaces of the walls, floors, and ceiling of the house are observed to be at an average temperature of
12
o
C
in winter and
23
o
C
in summer. Determine the rates of radiation heat transfer between this person and the surrounding surfaces in both summer and winter if the exposed surface area, emissivity, and the average outer surface temperature of the person are
1.6
m
2
,
0.95
,
and
32
o
C,
respectively.
Consider a person standing in a room maintained at20°C at all times. The inner surfaces of the walls, floors, andceiling of the house are observed to be at an average temperature of 12°C in winter and 23°C in summer. Determine therates of radiation heat transfer between this person and the surroundingsurfaces in both summer and winter if the exposedsurface area, emissivity, and the average outer surface temperatureof the person are 1.6 m2, 0.95, and 32°C, respectively.
A 1000-W iron is left on the ironing board with its base exposed to the air at 23°C. The convection heat transfer coefficient between the base surface and the surrounding air is 20 W/m2 ·°C. If the base has an emissivity of 0.4 and a surface area of 0.02 m2 , determine the temperature of the base of the iron.
A 50-cm * 50-cm circuit board that contains 121 square chips on one side is to be cooled by combined natural convection and radiation by mounting it on a vertical surface in a room at 25°C. Each chip dissipates 0.18 W of power, and the emissivity of the chip surfaces is 0.7. Assuming the heat transfer from the back side of the circuit board to be negligible, and the temperature of the surrounding surfaces to be the same as the air temperature of the room, determine the surface temperature of the chips. Evaluate air properties at a film temperature of 30°C and 1 atm pressure. Is this a good assumption?
Chapter 1 Solutions
Heat And Mass Transfer (asia Higher Education Engineering/computer Science Mechanica)
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.