Handbook of air conditioning and refrigeration / Shan K

TABLE 4.4 Values of F 0 – n and T 4 RnF 0 – n in Example 4.1
the shape factor F 0 –1 � 0.04. Here L is the horizontal distance from the occupant to the north partition
wall. The shape factors F 0 – 2, F 0 – 3, and F 0 – 4 can be calculated in the same manner.
2. To determine the shape factor F 0 – 5 for the radiation from the occupant (surface 0) to the floor
(surface 5), we note that the vertical distance L from the center of the seated occupant to the floor is
1.8 ft. From the curves in Fig. 4.2, the ratio b/L � 3/1.8 � 1.67, and the ratio a/L � 4.5/1.8 �
2.5; thus the shape factor F 0 – 5 � 0.068. All the remaining shape factors can be determined in the
same manner as listed in Table 4.4.
3. For the north partition wall (surface 1),
T 4 R1 F 0 – 1 � (75 � 460) 4 � 0.04 � 32.77 � 10 8
Other products T 4 Rn F 0 – n can be similarly calculated, as listed in Table 4.4. The sum of the products
�T 4 Rn F 0– n � 832.56 � 10 8 . Therefore
That is,
T 4 Rad � 832.56 � 10 8
T Rad � 537.2°R or T rad � 77.2°F(25.1°C)
4. The sum of the shape factors �F 0 – n � 0.994 is nearly equal to 1.
INDOOR AND OUTDOOR DESIGN CONDITIONS 4.13
Surface Shape
Surface temperature, °R factor b/L a/L F 0– n T 4 RnF 0– n � 10 8
North partition wall 535 F0 – 1
F0 – 2
F0 – 3
F0 – 4
0.6
0.6
2.2
2.2
1.5
3.5
1.5
3.5
0.04
0.045
0.07
0.087
32.77
36.87
57.35
71.27
East partition wall 535 F0 – 17
F0 – 18
F0 – 19
F0 – 20
0.63
0.63
0.17
0.17
0.29
0.86
0.29
0.86
0.014
0.03
0.004
0.009
11.47
24.58
3.28
7.37
South partition wall 535 F0 – 9
F0 – 10
F0 – 11
F0 – 12
0.73
0.73
0.2
0.2
0.5
1.17
0.5
1.17
0.023
0.038
0.008
0.013
18.84
31.13
6.55
10.65
West wall 540
540
F0 – 13
F0 – 14
0.4
0.4
0.67
2
0.018
0.03
15.31
25.51
West window 548
548
F0 – 15
F0 – 16
1.6
1.6
0.67
2
0.04
0.07
36.07
63.13
Floor 538 F0 – 5
F0 – 6
F0 – 7
F0 – 8
1.67
1.67
5
5
2.5
5.8
2.5
5.8
0.068
0.073
0.087
0.102
56.97
61.16
72.89
85.45
Ceiling 537 F0 – 21
F0 – 22
F0 – 23
F0 – 24
1.36
1.36
0.45
0.45
0.68
1.59
0.68
1.59
0.033
0.052
0.015
0.025
27.44
43.24
12.47
20.79
� 0.994 8.32.56 � 10 8