Handbook of air conditioning and refrigeration / Shan K

4.12 CHAPTER FOUR
FIGURE 4.4 Dimension, in feet, of a private office.
surroundings, on radiant exchange between an occupant or any substance and the enclosure. Such
an influence may be significant if the mean radiant temperature is several degrees higher than the
temperature of the indoor air.
Example 5.1. The dimensions of a private office and the location of a person seated within it are
shown in Fig. 4.4. The surface temperatures of the enclosure are as follows:
West window 88°F (31.1°C)
West wall 80°F (26.7°C)
North partition wall 75°F (23.9°C)
East partition wall 75°F (23.9°C)
South partition wall 75°F (23.9°C)
Floor 78°F (25.6°C)
Ceiling 77°F (25°C)
Calculate the mean radiant temperature of the enclosure that surrounds this office. The orientation
of the seated occupant is unknown.
Solution
1. Regarding the north partition wall, the shape factor denotes the fraction of the total radiant energy
that leaves the outer surface of the clothing of the occupant (surface 0) and arrives directly on
the north partition wall (surfaces 1, 2, 3, and 4) and is given by
F 0 – 1,2,3,4 � F 0 – 1 � F 0 – 2 � F 0 – 3 � F 0 – 4
Here F 0 – 1 is the shape factor for the radiation from surface 0 to surface 1 of the north partition wall.
Based on the curves in Fig. 4.3, for a ratio of b/L � 1.8/3 � 0.6 and a ratio of a/L � 4.5/3 � 1.5,