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302.
CHAPTER 15
1949 Guide;
- Table 18. Instantaneous Rates op Heat Gain Due to Solar and SkyRadiation fob Single Sheets or Unshaded Common Window Glass*- b
Computed for Solar Declination of 18 Deg--August 1
Note: To determine the total instantaneous rate of heat gain add the term 1.04 (k-fi) to the values shown in the table (see Equation 10).
Sun Time
Solar Altitude
N
Instantaneous Rate op Heat Gain, Btu per Hour for Each Square Foot of Unshaded Glass
NE E SE S SW W NW Horizontal
85 Deg North Latitude
7
8 9 10 11
3'
5 6\
7.5 20.6 34.0 47.5 -161.5' - 74.5 83.0 74.5 6L5 *47.5 ` 34.0
20.5 . 7.5
19 26 18 15 16 16 16 16 16 16 18 26 19 .
77 146
148 118
67 25 16 16 16 15
13 10 3
84 173 * 193 172 124 57
16
16 16 15 13 10
3
40 98 121
120 95 57 25 16 16 15 13 10
3
3333 10 10 10 10 13 13 13 13 16 16 15 15 22 16 16 16 25 16 \ 16 16 28 25 16 16 25 67 57 25 22 95 124 07 16 120 172 118 13 121 193 148 10 98 173 146
3 40 84 77.
-.- t. . so Deg North Latitude i
. o'o
22 88
21J> - 23 146
8
. 34.5
16 140
47.5
15 104
60.0 16 53
11
72.0
16 . 19
78.0
16 16
72.0 16 16
2 60.0 16 16
3
47.5
15 15
34.5
16 14
5
21.6 . ` 23
11
6.
9.0
22 4
97 47
4. 4
176 105194 130
11 14
11
' 14
171 133 20 15
126 112 33 16
56 74 42 16
16 34 45 34
16 16 42 74
16 16 33 112
15 15 20 133
14
14 * 14
130
11 11. 11 105
4 4 4 47
44 11 11 14 14 15 15 16 10 16 16 16 16 56 19 126 . 53 171 104 194 140 176 146 97 88
12 68 143 205 252 282 293 1 282 252 205 148 68* 12 .
is ;
74 144 205 248 . 277 288 277 248 . 205 144
74 15 .
85 Deg North Latitude
. 7-
, 10 . . -12 . 1 p.m. 2 3... 5 6
10.0 ' 22.5
34.5 1 * 46.6 '
' 58.5 68.5 73.0 68.5
' 58.5 46.5 34.5 22.5 10.0
21 97 109
19 ' 143
179
14 133 194
15 ' 90
170
.16 38 . 120.
16 . 16
56
. 16 ,. 16
16-
16 16 16
16 16 ' 16
15 . 15
15
* 14
14 * 14
19 11 11
21 4 4
63 110
140 144 128 ' 91 45
17 16
15 14 11.
4
4 11 15 28 47 62
68 62
47 *8 . 15
. 11 4
4 11 14 15
16 17 45 91 , 128 144 140 110 53
4 11 14 15
16 16 16 ' 56 126 170 194 179 109
4'
11 14 15 16 16 16
16. 38 90 133 143 97
' 19 79 144 200 '
243 . 269 279 269
243 ' . . 200
144 79 19
6 a.in. 6 7
8 9 10 Il
ia
1 jun.
1.5 11.5
34.5 45.5 56.0 64.5 68.0
56.0 45.5 34.523.0 11.5
1.5
40 Deg North Latitude
7 23
15 14 15 16 16 16 16 16 1514 15 23-7
18 106 141 122
.76 30 ' 16 16 16 16 15 14
11 5 1
17 6
120 62
181 118
194 147
172 156
125 . 144
53 110
16 62
16 22
. 16
16
15 15
14 14
11 - 11
5'- 5
1 .1
111
5 .5
5
11 . 11
11
19 14 14
42 15 15
66 16- 16
85> 22
16
94 - 62 , 16
85 110 . 52
66 144 125
12. 156. 172
19 - 147 194
11 .118 181
5 ' 62
120
. - 6 . 17
1 5 11 14 15 16 - 10 16: 16 30
76 122141 106 .
18
2 24-. 82 145 196 235 261
261 235 196 '* 145. i
24 * 2
Cooling'Load .
303
Table 18. Instantaneous Rates op Heat Gain Due to Solas and Sky Radiation fob Single Sheets op Unshaded Common Window Glass*- b (Concluded)
Sjjjj Tims
Solar Altitude
$ Dec
N
Instantaneous Rate of Heat Gain, Btu per Hour for Each Square Foot of Unshaded Glass
NE E SE S SW. w NW Horizontal
5 a.m. . T6 - i
7
8 .9
10 . 11
12 1 p.ml 2 3 4 5 6 7.
2.0 12.5 23.0 33.5 44.0 53.0 60.0 63.0 60.0 53.0 44.0 33.5 23.0 12.5
2.0
45 Deg North Latitude
9 23 23 8 .1 1 1 1
22 111 129
68
6
6 .6
.6
13 135 182 121 11 11 - 11 11
14 116 192 153 24 14 14 14
15 63 168- 166 55 15 15 15
16 22 123 154 88 16 16 16
16 16 ' 56 127 113 30 16 > 16
16 16 16 76 119 76 16 16
16 16 16 30 113 127 56:- 16
16 16 16 16 88 154 123 22
15 15 15 15 55 166 168 63
14 14 14 14 24 153 192 116
13 . 11 11 11 11 121 182 135
22 6 6 6 6 68 129 111
9 1 1 l 1 8 23 23
2 . 28
82 141
189 225 249 256 249 225 189 .141 82 ; 28
2
50 Deg North Latitude
5 a.m. 6 7 8
9 10 11 12 1 p.m. ' 2 `3 4 5 6
4.6 13.5 23.5 33.0 42.0 50.0 56.0 58.0 56.0 50.0 42.0 33.0 23.5 13.5 4.5
18 48 22 119 1! 131 13 . . 103 14 51 16 19 16 15 1G 1G 16 16 16 . 16 14 14
13 13 11 11 22 6 18 2
48 . 139
183 190 165 122 55
16
16 16 14
13 11 6
2
17 75 127 161 173 166 138 92 41 16 14 13 11
, 26 <
2 6 11 30
69 109 133
140 133 109 69 30.
11 62
2 6 11 13 14 16 41 92 138 . 166 173 161 127
. 75 17- -
.2 6 11
13 14 16 16 16 55 122 165 190 183
139 48 -
2 6 11 13 14
16 16 16 ' 16 19 51 103
131 119 48
32 84
138 179 214 ' 235 242 235 214 179
138 84 32
5
Table compiled from.solar radiation transmission data developed by A.S.H.V.E. Research Labora tory* and direct intensity values developed by Moon*, reoently.enlarged and revised by the A.S.H.V E. Re search Laboratory.
b For relatively clear atfhosphere at sea level; Far hasy atmosphere values may be reduced 10 per cent! Above sea level add 'one per cent per 1006 ft elevation.
inclusive, and for all exposures from 10:00 a.m. to 2:00 p.m. inclusive. For Southern exposures at 8:00 a.m. or at 4:00 p.m. the error may be 15 per cent. At noon this method gives accurate results; the error becomes progressively larger as the time differs from noon.
In regard to glass blocks, data oh the over-all unit conductances for heat transfer by convection and conduction are given in Table 18, Chapter 6; these will serve also for cooling load calculations for shaded or north-
Table 19. Ratio op Instantaneous Rate of Heat Gain Thbouoh Single Thickness op Heat Absobbing Sunlit Glass to Heat Gain fob Common Glass as Given in Table 18
Trans missivity*
0.90 0.87 0.80
Approximate Ratio.
1.02 1.0 0.93 '
Trans- MISSIVITY*
0.70 0.60 - 0.50
Approximate Ratio
0.85. : 0.76
0.68
- * For direct solar radiation at normal incidents-
Trans missivity*
0.40 0.30 0.20
Approximate , Ratio
0.60 0.52 0.45