12 th International Conference on Sustainable Energy Environmental

12 th International Conference on Sustainable Energy & Environmental Protection SEEP 2019 University of Sharjah ESTIMATING THE OPTIMUM TILT ANGELS FOR SOUTH-FACING SURFACES IN UNITED ARAB OF EMIRATES (UAE) Ramez Abdallah 1, Adel Juaidi 1, Tareq Salameh 2 1 Mechanical Engineering Department- Faculty of Engineering & Information Technology, An-Najah National University, P. O. Box 7, Nablus, Palestine 2 Sustainable and Renewable Energy Engineering Department, University of Sharjah, P. O. Box 27272, Sharjah, United Arab Emirates ABSTRACT The Optimum tilt angle of a solar panels or collectors is crucial to be considered when determining the parameters that affect the performance of them. A mathematical model is used to determine the optimum tilt angle and calculating the solar radiation falling on a south facing surface on a daily, monthly, seasonally, semi-annually and yearly basis. The results show that daily and monthly adjustments of the solar panels or collectors for most of the emirates of the UAE can receive about 20 % more solar energy than the case of a solar panels or collectors fixed on a horizontal surface. While seasonally and semi-annually adjustments can receive about 18% more solar energy. I. e. that it is worth to change the solar panels or collectors 12 times yearly (monthly) or at least 2 times in a year (semi-annually). The yearly optimum tilt angle for the most of the emirates of the UAE is about 23°. INTRODUCTION The solar energy is the best source of renewable energy in world and it could be the only source of renewable energy in most countries of the Middle East. Solar energy could be used directly to heat water as in the solar collectors or could be converted to electricity as in the solar panels. In the United Arab Emirates (UAE) as in most of the Middle East countries solar energy is considered the only source of clean energy with high potential in the near future for using it to supply energy demands particularly in remote locations. The most important factor that affects the solar radiation is the tilt of the PV. The optimal angle of the execution should be defined as the background for the best productivity of the PV panels. On the other hand, some panels are installed on the best wintry, summery, monthly, daily, or yearly angle. METHODOLOGY Figure 1: Shows the Latitude angle(∅), altitude angle (α) and tilt angle (β) Figure 2: The daily optimum tilt angle, βopt, d for Abu Dhabi RESULTS AND DISCUSSION Table 1: The annually optimum tilts angle βopt, y CONCLUSION Emirate βopt, y Abu Dhabi Dubai Sharjah, Ajman, Umm Quain Fujairah Ras Al-Khaimah Al ain 22. 68 23. 39 23. 48 23. 21 23. 66 22. 50 Ø For all the emirates of the UAE there is no need to design a solar panel or collector with negative tilt angle. Since, the solar energy gain due to the negative values of the optimum tilt angle is less than 1%. Table 2: The Semi-annually optimum tilts angle βopt, sa Emirate Abu Dhabi Dubai Sharjah, Ajman, Umm Quain βopt, sa -0. 01 0. 70 0. 79 0. 52 0. 97 -0. 19 βopt, sa 45. 13 45. 87 45. 96 45. 68 46. 14 44. 95 Period Warm period (April to September) Cold period (October to March) Fujairah Ras Al. Khaima h Al ain Figure 3: Monthly optimum tilt angle, βopt, m for Abu Dhabi, UAE. Table 3: The tilt factor on daily, monthly, Seasonally, Semiannually and yearly optimum tilt angle basis for the emirates of the UAE. Emirate Abu Dhabi Dubai F 1. 197 1. 203 1. 204 1. 202 1. 206 1. 195 βopt, F 1. 194 1. 201 1. 202 1. 199 1. 203 1. 193 βopt, s F 1. 176 1. 182 1. 183 1. 180 1. 184 1. 174 βopt, s F 1. 174 1. 180 1. 181 1. 178 1. 182 1. 172 F 1. 084 1. 090 1. 088 1. 092 1. 082 m a βopt, y Ø The daily and monthly optimum tilt angle for all the emirates of the UAE throughout the year is between -13. 0° in June and 56° in December. . Ø The semi-annually optimum tilt angle for emirates of the UAE throughout the year is 0. 0° in the warm period (April to September) and 45° in the cold period (October to March). . Sharjah, Ajman, Ras al. Fujairah Al ain Umm Quain Khaimah βopt, d Ø Compared to a horizontal surface, yearly, semiannually, seasonally, monthly and daily adjustments of solar panels or collectors will receive up to 9%, 18%, 20%, and 20% more solar energy, respectively. Figure 4: The Seasonally optimum tilt angle, βopt, s for Abu Dhabi, UAE Ø It can be concluded that the monthly optimum tilt angle for a particular month is the average of the daily optimum tilt angle for this particular month. While the seasonally, semi-annually and yearly optimum tilt angle is the average monthly optimum tilt angle for that particular period. .