The International Conference on
Renewable Energy: Generation and Applications
4-7 March 2012, Al Ain, UAE
Optimum Tilt Angle and
Orientation of Solar Surfaces in
Abu Dhabi, UAE
Dr. Farzad Jafarkazemi (f_jafarkazemi@azad.ac.ir)
Islamic Azad University, South Tehran Branch, Tehran, Iran
Please cite this paper as:
Jafarkazemi, F., Saadabadi, A., Optimum Tilt Angle and Orientation of Solar Surfaces in Abu
Dhabi, UAE, Renewable Energy, Vol. 56, August 2013, Pages 44-49
Contents
2
Motivation of this research
Motivation of this research
Motivation of this research
Miss-alignment in
Small systems
Abu Dhabi Municipality, 100kW
Sheikh Sultan Bin Zayed Mosque, 55kW
New PV Installations
Abu Dhabi National Exhibition Centre 100 kW
Al Mamoura Building, 210kW
Abu Dhabi Distribution Centre Car Park, 125kW
Abu Dhabi Aircraft Technology Centre, 300kW
Officers Club, 100 kW
Masdar Institute, 1MW
Methodology
15
Methodology
16
Methodology
Linear (Angstrom – Prescott)
Quadratic (Akinoglu & Ecevit)
Third order (Samuel)
Logarithmic (Ampratwum & Dorvlo)
Linear – Logarithmic (Newland)
Exponential (Elagib & Monsell)
Power (Coppolino)
 A. ASSI and M.JAMA, Predicting Global Solar Radiation on Horizontal Using Sunshine Duration in
Abu Dhabi – UAE, 25th European Photovoltaic Solar Energy Conference, Sep. 2010, Spain
 M.D. Islam, I. Kubo, M. Ohadi and, A.A. Alili, Measurement of Solar Energy Radiation in Abu Dhabi
, UAE), Applied Energy, 2009
 NASA SSE model (22-year average)
 National Center of Meteorology and Seismology(NCMS) in Abu Dhabi
17
Measurements-2
National Center of Meteorology and Seismology(NCMS) in Abu Dhabi
A. ASSI and M.JAMA, Predicting Global Solar Radiation on Horizontal Using Sunshine Duration in Abu Dhabi –
UAE, 25th European Photovoltaic Solar Energy Conference, Sep. 2010, Spain
18
Methodology
Month
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Des
Global solar radiation on horizontal surface
NASA SSE model
M.D. Islam et. al
14.72
14.08
17.28
17.42
18.83
20.63
22.75
22.79
25.85
25.06
26.03
24.62
23.22
24.52
22.75
23.51
21.78
22.32
19.40
19.40
16.31
15.26
13.61
11.30
19
Methodology
2
3

1.391 - 3.560 K T + 4.189 K T - 2.137 K T if

2
3
H

1.311 - 3.022 K T + 3.427 K T - 1.821 K T if
Hd
HO
s  81.4
s  81.4


 360 n  


1
+
0.033
cos





24 × 0.0036 × Gs 

 365  




 cos  cos  sin     sin  sin  
s
s


180


KT 
H
HO
20
Methodology
2
Month
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
H
14.72
17.28
18.83
22.75
25.85
26.03
23.22
22.75
21.78
19.40
16.31
13.61
Hd
Hb
Ho
4.37
5.77
6.97
7.57
7.61
7.80
8.24
7.80
6.87
5.73
4.30
4.21
10.35
11.51
11.86
15.18
18.24
18.23
14.98
14.95
14.91
13.67
12.01
9.40
24.33
28.57
33.39
37.54
39.76
40.41
39.96
38.25
34.78
29.90
25.27
23.06
KT
0.61
0.60
0.56
0.61
0.65
0.64
0.58
0.59
0.63
0.65
0.65
0.59
21
Methodology
HT  R × H
R = D+
H d  1 + cos 
2
H 

 1 - cos  
+

g



2



max(0, G (ss , sr ))

D
max0, G (ss ,sr )  G (s , sr )
if ss  sr
if ss  sr
  bA



(
a'
B)(


)

(a'
A
bB)

(sin

sin

)

1
2
1
2
 180 2


1 
G (1 , 2 ) =
aC (cos1 - cos2 )  (bA/2) sin 1 cos1 - sin 2 cos 2  
2d 

2
2
 bC / 2 sin 1  sin 2







| sr |= min s , cos-1  AB + C A 2 - B 2 + C 2 )/(A2 + C 2 





 ss  min s , cos-1  AB - C A 2 - B 2 + C 2 )/(A2 + C 2 


 
 sr   sr
  sr
 ss  
if (A > 0 & B > 0 )or A  B
if
otherwise


  ss

  ss

if (A > 0 & B > 0 )or A  B
if
otherwise
22
Optimum Orientation
Optimum orientation for fixed tilt angle is south direction, except
tilt angles more than 75o. From this point, optimum orientation is 50o.
23
Optimum Orientation
2
Azimuth
angle 
opt
Global
Radiation
Ratio to radiation
on horizontal
0
10
20
30
40
50
60
70
80
90
22
22
21
21
19
17
14
10
6
0
7746.9
7737.6
7709.8
7665.3
7606.1
7536.3
7462.3
7394.3
7345.4
7327.7
1.057
1.056
1.052
1.046
1.038
1.028
1.018
1.009
1.002
1.000
24
Optimum Tilt Angle
2
Solar radiation on inclined surface is a function of tilt angle and the
Optimum tilt angles are different for months.
25
Optimum Tilt Angle
2
Solar radiation on inclined surface is a function of tilt angle and the
Optimum tilt angles are different for months.
26
Optimum Tilt Angle
27
Optimum Tilt Angle
2
Monthly
opt
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
50
39
25
10
-3
-9
-6
5
20
36
48
52
Ht
Seasonal
20.54
20.78 Winter
20.06
22.85
25.74 Spring
26.15
23.19
22.66 Summer
22.63
22.63
22.33 Autumn
19.66
opt
39
-1
6
45
Ht
20.25
20.78
19.64
22.53
25.73
25.97
22.85
22.65
22.12
22.42
22.30
19.55
Bi-annual
Heating
period
Cooling
period
Heating
period
opt
Ht
Yearly
20.39
42 20.76
19.43
22.68
25.67
25.81 Whole
2
23.04 (Entire)
22.64
21.80
22.54
42 22.22
19.42
opt
Ht
22
18.62
20.05
20.04
22.49
24.02
23.52
21.36
21.93
22.62
22.10
20.44
17.53
28
Optimum Tilt Angle
2
Period of time
Monthly
Seasonal
Bi-annual
Fixed Yearly
Fixed Vertical
Fixed Horizontal
Ht
Ratio to radiation on
horizontal surface
8189
8115
8104
7747
4304
7328
1.117
1.107
1.105
1.057
0.587
1
Comparison between annual solar radiation shows that, the best
choose is using the bi-annual tilt angle(twice a year).
29
Optimum Tilt At Different Orientation
Optimum tilt angles change by diversion of surface from the south
direction. Maximum effect in autumn and winter months.
30
Optimum Tilt At Different Orientation
2
Even by adjusting optimum tilt angle for every azimuth angle, Solar
radiation on a tilted surface decreases in autumn and winter months.
31
Radiation on Vertical Surface
Source: BIPV for the GCC region, Mahieddine Emziane, WFES 2012
32
Radiation on Vertical Surface
2
Monthly solar radiation on a west-facing vertical surface is more than
south-facing in summer month and it is different for autumn and winter.
33
Radiation on Vertical Surface
2
Azimuth
Angle ( )
Annual solar
radiation
0
10
20
4153
4317
4432
30
40
50
60
70
80
90
4498 4517 4496 4446 4383 4326 4304
The optimum orientation for vertical solar surface is 40o when
monthly adjustment is used.
34
Conclusions
 Adjust the tilt angle, at least twice a year.
 The yearly optimum tilt angle for Abu Dhabi is (βopt =22o).
 The optimum orientation angle is in the south direction.
 Adjusting the optimum tilt angle to different orientations
making up the loss of solar radiation.
 The optimum tilt angle decreases by diversion from the
south direction.
 Vertical surfaces facing west receive higher solar
radiation in summer in comparison to those facing south.
35
Thanks For Your Attention