Sol-air temperature Tos
From ASHRAE 1989, with permission
Values given as a function of time and of surface orientation for July 21 at 40°N latitude, assuming a/ho = 0.30 (h·ft2·°F)/Btu [0.053 (m2·K)/W], summer design conditions for dark surface.
For other values of a/ho, adjust the difference between Tos and air temperature To according to Eq. (6.39) in the text.
Time |
Air Temp., |
N |
NE |
E |
SE |
S |
SW |
W |
NW |
HOR |
100 |
76 |
76 |
76 |
76 |
76 |
76 |
76 |
76 |
76 |
69 |
200 |
76 |
76 |
76 |
76 |
76 |
76 |
76 |
76 |
76 |
69 |
300 |
75 |
75 |
75 |
75 |
75 |
75 |
75 |
75 |
75 |
68 |
400 |
74 |
74 |
74 |
74 |
74 |
74 |
74 |
74 |
74 |
67 |
500 |
74 |
74 |
74 |
74 |
74 |
74 |
74 |
74 |
74 |
67 |
600 |
74 |
90 |
117 |
121 |
99 |
77 |
77 |
77 |
77 |
81 |
700 |
75 |
90 |
131 |
144 |
120 |
82 |
82 |
82 |
82 |
102 |
800 |
77 |
87 |
130 |
151 |
134 |
89 |
86 |
86 |
86 |
122 |
900 |
80 |
91 |
122 |
148 |
141 |
105 |
91 |
91 |
91 |
140 |
1000 |
83 |
95 |
109 |
137 |
141 |
118 |
96 |
95 |
95 |
155 |
1100 |
87 |
100 |
101 |
122 |
136 |
129 |
105 |
100 |
100 |
166 |
1200 |
90 |
103 |
103 |
104 |
125 |
134 |
125 |
104 |
103 |
172 |
1300 |
93 |
106 |
106 |
106 |
111 |
135 |
142 |
128 |
107 |
172 |
1400 |
94 |
106 |
106 |
106 |
107 |
129 |
152 |
148 |
120 |
166 |
1500 |
95 |
106 |
106 |
106 |
106 |
120 |
156 |
163 |
137 |
155 |
1600 |
94 |
104 |
103 |
103 |
103 |
106 |
151 |
168 |
147 |
139 |
1700 |
93 |
108 |
100 |
100 |
100 |
100 |
138 |
162 |
149 |
120 |
1800 |
91 |
107 |
94 |
94 |
94 |
94 |
116 |
138 |
134 |
98 |
1900 |
87 |
87 |
87 |
87 |
87 |
87 |
87 |
87 |
87 |
80 |
2000 |
85 |
85 |
85 |
85 |
85 |
85 |
85 |
85 |
85 |
78 |
2100 |
83 |
83 |
83 |
83 |
83 |
83 |
83 |
83 |
83 |
76 |
2200 |
81 |
81 |
81 |
81 |
81 |
81 |
81 |
81 |
81 |
74 |
2300 |
79 |
79 |
79 |
79 |
79 |
79 |
79 |
79 |
79 |
72 |
2400 |
77 |
77 |
77 |
77 |
77 |
77 |
77 |
77 |
77 |
70 |
Avg. |
83 |
89 |
95 |
100 |
99 |
95 |
99 |
100 |
95 |
107 |