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.,
°F

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