THE EFFECT OF WIND VELOCITY DISTRIBUTION ON

Proceedings of BS2013:
13th Conference of International Building Performance Simulation Association, Chambéry, France, August 26-28
THE EFFECT OF WIND VELOCITY DISTRIBUTION ON UNGLAZED
TRANSPIRED COLLECTORS
Convective heat transfer coefficients (CHTC) on
vertical façades
𝑉
𝑉
Wind effects on UTC
πœ‚ = 𝛼 1 +
Ο΅
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β„Ž
+β„Ž
Ο΅
πœŒπ‘ 𝑉
Proceedings of BS2013:
13th Conference of International Building Performance Simulation Association, Chambéry, France, August 26-28
𝑇
𝑇
𝑇
Ο΅=
𝑇
𝑇
βˆ’π‘‡
βˆ’π‘‡
Ο΅
πœ– = 1 βˆ’ 1 + 𝑅𝑒 π‘šπ‘Žπ‘₯ 1.733𝑅𝑒
, 0.02136
× 1 βˆ’ 1 + 0.2273𝑅𝑒 × π‘’π‘₯𝑝 βˆ’0.01895
𝑃 20.62 𝑑
βˆ’
𝐷
𝑅𝑒 𝐷
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Proceedings of BS2013:
13th Conference of International Building Performance Simulation Association, Chambéry, France, August 26-28
13.5 cm
2 cm
ο‚·
DESCRIPTOR
ο‚·
0.5
1
1
1
1
DIRECTION
RELATIVE TO
THE UTC
1
1
1
CARDINAL
DIRECTION
0.5
13.5
13.0
12.5
12.0
11.5
2
8
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Indicates height
above ground
Proceedings of BS2013:
13th Conference of International Building Performance Simulation Association, Chambéry, France, August 26-28
𝑉
Local velocity distribution near the UTC area
𝑉
Convective heat transfer coefficient (CHTC)
β„Ž
𝑉
𝑉 𝑉
𝑉 𝑉 𝑉 𝑉
β„Ž = 5.90𝑉
+ 3.95
β„Ž = 6.42𝑉
+ 3.17
β„Ž = 7.42𝑉
+ 2.98
𝑉
𝑉
South-West Wind
South-West Wind
South Wind
South Wind
North-West Wind
North-West Wind
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Proceedings of BS2013:
13th Conference of International Building Performance Simulation Association, Chambéry, France, August 26-28
%πΈπ‘Ÿπ‘Ÿπ‘œπ‘Ÿ =
(π‘‰π‘Žπ‘™π‘’π‘’ π‘“π‘œπ‘Ÿ π‘Žπ‘ π‘ π‘’π‘šπ‘’π‘‘ π‘‘π‘–π‘ π‘‘π‘Ÿπ‘–π‘π‘’π‘‘π‘–π‘œπ‘›
βˆ’π‘‰π‘Žπ‘™π‘’π‘’ π‘“π‘œπ‘Ÿ π‘Žπ‘π‘‘π‘’π‘Žπ‘™ π‘‘π‘–π‘ π‘‘π‘Ÿπ‘–π‘π‘’π‘‘π‘–π‘œπ‘›)
× 100
π‘‰π‘Žπ‘™π‘’π‘’ π‘“π‘œπ‘Ÿ π‘Žπ‘π‘‘π‘’π‘Žπ‘™ π‘‘π‘–π‘ π‘‘π‘Ÿπ‘–π‘π‘’π‘‘π‘–π‘œπ‘›
UTC thermal efficiency
πœ‚
πœ‚
DESCRIPTOR
CASE 1: WITH
PROXIMITY
MODEL
1 m/s
3 m/s
CASE 2:
WITHOUT
PROXIMITY
MODEL
1 m/s
3 m/s
DESCRIPTOR
CASE 1: WITH
PROXIMITY
MODEL
1 m/s
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3 m/s
CASE 2:
WITHOUT
PROXIMITY
MODEL
1 m/s
3 m/s
Proceedings of BS2013:
13th Conference of International Building Performance Simulation Association, Chambéry, France, August 26-28
Comparison of wind tunnel and solar simulator
results (Bambara, 2012)
πœ‚
πœ‚
πœ‚
πœ‚
Convective heat transfer coefficient
2
hc (W/m /K)
Convective heat transfer coefficient
2
hc (W/m /K)
translate to about 160
W.hr/m2 of heat loss through convection.
Reference wind velocity
Reference wind velocity
(m/s)
Thermal efficiency Ξ· (%)
Wind Tunnel (1 m/s)
Solar Simulator (1 m/s)
Wind Tunnel (3 m/s)
Solar Simulator (3 m/s)
2
Air suction rate (kg/hr/m )
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(m/s)
Proceedings of BS2013:
13th Conference of International Building Performance Simulation Association, Chambéry, France, August 26-28
cp
𝑉 𝑃
𝜈
𝑉𝐷
𝑅𝑒 =
𝜈𝜎
𝑅𝑒 =
𝑅𝑒 =
𝑉𝑃
𝜈
𝑅𝑒 =
𝑉𝑃
𝜈𝜎
⁰
⁰
⁰
𝑉
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Proceedings of BS2013:
13th Conference of International Building Performance Simulation Association, Chambéry, France, August 26-28
Ο΅
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