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Modeling Spatio-Temporal Dynamics of Optimum Tilt Angles for Solar Collectors in Turkey  [PDF]
Can Ertekin,Fatih Evrendilek,Recep Kulcu
Sensors , 2008, DOI: 10.3390/s8052913
Abstract: Quantifying spatial and temporal variations in optimal tilt angle of a solar collector relative to a horizontal position assists in maximizing its performance for energy collection depending on changes in time and space. In this study, optimal tilt angles were quantified for solar collectors based on the monthly global and diffuse solar radiation on a horizontal surface across Turkey. The dataset of monthly average daily global solar radiation was obtained from 158 places, and monthly diffuse radiation data were estimated using an empirical model in the related literature. Our results showed that high tilt angles during the autumn (September to November) and winter (December to February) and low tilt angles during the summer (March to August) enabled the solar collector surface to absorb the maximum amount of solar radiation. Monthly optimum tilt angles were estimated devising a sinusoidal function of latitude and day of the year, and their validation resulted in a high R2 value of 98.8%, with root mean square error (RMSE) of 2.06o.
Modeling Spatio-Temporal Dynamics of Optimum Tilt Angles for Solar Collectors in Turkey
Can Ertekin,Fatih Evrendilek,Recep Kulcu
Sensors , 2008,
Abstract: Quantifying spatial and temporal variations in optimal tilt angle of a solar collector relative to a horizontal position assists in maximizing its performance for energy collection depending on changes in time and space. In this study, optimal tilt angles were quantified for solar collectors based on the monthly global and diffuse solar radiation on a horizontal surface across Turkey. The dataset of monthly average daily global solar radiation was obtained from 158 places, and monthly diffuse radiation data were estimated using an empirical model in the related literature. Our results showed that high tilt angles during the autumn (September to November) and winter (December to February) and low tilt angles during the summer (March to August) enabled the solar collector surface to absorb the maximum amount of solar radiation. Monthly optimum tilt angles were estimated devising a sinusoidal function of latitude and day of the year, and their validation resulted in a high R2 value of 98.8%, with root mean square error (RMSE) of 2.06o.
Solar Receivers Optimum Tilt Angle at Southern Hemisphere
Soulayman Soulayman, Alhelou Mohammad, Nouredine Salah
Open Access Library Journal (OALib Journal) , 2016, DOI: 10.4236/oalib.1102385
Abstract: One of the important parameters that affects the performance of a solar collector is its tilt angle with the horizon. This is because the variation of tilt angle changes the amount of solar radiation reaching the collector surface. Meanwhile, is the rule of thumb, which says that solar collector should be orientated towards the Equator with a tilt equal to latitude, valid for high latitudes region? Thus, it is required to determine the optimum tilt for Equator facing collectors. In addition, the question may rise: how much adjustments of Equator facing solar collector tilt angle is reasonable to do during a year? A mathematical model was used for estimating the solar radiation on a tilted surface, and to determine the optimum tilt angle and orientation (surface azimuth angle) for the solar collector at any latitude. This model was applied for determining optimum tilt angle in the high latitudes zone in the Southern Hemisphere, on a daily basis, as well as for a specific period. The optimum angle was computed by searching for the values for which the radiation on the collector surface is a maximum for a particular day or a specific period. The results reveal that changing the tilt angle 12 times in a year (i.e. using the monthly optimum tilt angle) maintains approximately the total amount of solar radiation near the maximum value that is found by changing the tilt angle daily to its optimum value. This achieves a yearly gain in solar radiation up to 1.8 times of the case of a horizontal surface while the daily gain reaches 60 times approximately. Moreover, general formulas are proposed for predicting daily optimum tilt angle and optimum tilt angle over any number of days.
不同方位角上太阳能集热器最佳倾角的确定
The optimum tilt angles of solar collectors for different azimuth angles
 [PDF]

钟林志,孙志新,许巧玲,严哲钦
福州大学学报(自然科学版) , 2015, DOI: 10.7631/issn.1000-2243.2015.01.0135
Abstract: 综合考虑太阳辐射量和热负荷的变化,以福州地区为例,分别以年最大得热量和年需最小辅助加热量为目标,计算得到不同方位角所对应的集热器最佳倾角. 结果表明,正南朝向下,相较于以年最大得热量为目标确定的集热器最佳倾角,以年需最小辅助加热量为目标确定的集热器最佳倾角可节约11.7%的辅助加热量. 方位角对集热器最佳倾角也有较大影响. 当方位角的绝对值较大时,应采用较小的集热器倾角.
Considering the changes of solar radiation and heating load and taking Fuzhou region for instance,the optimum collector tilt angles at different azimuth angles were calculated based on the objectives of maximum annual heat gain and minimum annual auxiliary heating respectively. The results show that,when the collector facing due south,the optimum tilt angle obtained based on minimum annual auxiliary heating could reduce the heating supplement by 11.7%,compared to the angle obtained based on maximum annual heat gain. Azimuth angle has a great influence on the optimum collector tilt angle. A smaller collector tilt angle should be adopted when the absolute value of azimuth angle is lager
An Algorithm to Determine the Optimum Tilt Angle of a Solar Panel from Global Horizontal Solar Radiation  [PDF]
Emanuele Calabrò
Journal of Renewable Energy , 2013, DOI: 10.1155/2013/307547
Abstract: This paper proposes an algorithm to calculate the optimum tilt angle of solar panels by means of global horizontal solar radiation data, provided from Earth-based meteorological stations. This mathematical modeling is based on the maximization of the theoretical expression of the global solar irradiation impinging on an inclined surface, with respect to the slope and orientation of the panel and to the solar hour angle. A set of transcendent equations resulted, whose solutions give the optimum tilt and orientation of a solar panel. A simulation was carried out using global horizontal solar radiation data from the European Solar Radiation Atlas and some empirical models of diffuse solar radiation. The optimum tilt angle resulted was related to latitude by a linear regression with significant correlation coefficients. The standard error of the mean values resulted increased significantly with latitude, suggesting that unreliable values can be provided at high latitudes. 1. Introduction Most countries in the world have realized the need for reduction of gases emission to contrast the adverse global climatic change, encouraging the use of renewable and sustainable sources of energy. Indeed, large quantities of carbon dioxide, nitrogen, and sulfur oxides are emitted in the world by conventional energy sources, which are released to the earth’s atmosphere contributing to climate change. Furthermore, the world will soon run out of its conventional energy resources because of the rapid depletion of fossil fuel reserves. This future scenario and the risks associated with CO2 emissions and global warming have increased the interest in renewable energy. The major renewable energy systems include photovoltaics (PVs), solar thermal, wind, biomass, hydroelectric, and geothermal. However, among various renewable energy sources, the photovoltaic technology for power generation is considered well-suited technology, particularly for distributed power generation. Solar panel is the energy conversion fundamental component of PV systems or solar collectors. Solar panels use light energy from the sun to generate electricity through the photovoltaic effect, whereas solar thermal systems generate heat. The amount of electrical power produced from PV systems is related to the amount of solar irradiation projecting on the modules. Hence, the global solar irradiation on tilted surfaces facing in different directions should be considered to estimate thermal and electrical power obtained in architectural planning. The literature provides that solar power supplied by the modules
Optimum Tilt Angle and Orientation of Stand-Alone Photovoltaic Electricity Generation Systems for Rural Electrification  [PDF]
Prashanthini Sunderan,Adibah Mohd Ismail,Balbir Singh,Norani Muti Mohamed
Journal of Applied Sciences , 2011,
Abstract: The effect of tilt angle and orientation of Photovoltaic (PV) modules on the performance of Stand-alone Photovoltaic Electricity Generation Systems (SPVEGS) for rural electrification was investigated in this study. In order to have maximum irradiation converted into electricity, both the tilt angle and orientation of the PV surface should be optimum. It is found that the total irradiation captured on a tilted surface mounted in Ipoh, Malaysia can be maximized by positioning the PV modules at the monthly optimum tilt of βoptimum = φ-δ, facing North (γ = 180°) for the months April to August and facing South (γ = 0°) for the rest of the months throughout the year. The total irradiation on a tilted surface calculated in this study considered the beam, diffuse and reflected components of the radiation on a tilted surface. The total irradiation incident on surfaces tilted at β = φ, β = 0° and β = |φ-δ| were also investigated. A gain of 6.4 and 6.1%, respectively is achieved by positioning the PV modules at the monthly optimum tilt and orientation as compared to keeping them fixed throughout the year at horizontal (β = 0°) or at latitude (β = φ). PV modules maintained at a monthly tilt of β = |φ-δ| with South facing orientation at all times accounted for a loss of approximately 5.3% in total tilted irradiation as compared to tilting the PV modules to βoptimum with North and South facing surfaces. This indicates that the orientations of PV modules are equally as important as tilt angles.
Optimum Tilt Angle for Photovoltaic Solar Panels in Zomba District, Malawi  [PDF]
B. Kamanga,J. S. P. Mlatho,C. Mikeka,C. Kamunda
Journal of Solar Energy , 2014, DOI: 10.1155/2014/132950
Abstract: A study to determine the optimum tilt angle for installing photovoltaic solar panels in Zomba district, Malawi, has been conducted. The study determined the optimum monthly tilt angles of PV solar panels and the seasonal adjustments needed for the panels in order to collect maximum solar radiation throughout the year. In this study, global solar radiation (GSR) on four tilted surfaces was measured. The north-facing surfaces were titled at angles of 0°, 15°, 20°, and 25°. The GSR data was used to determine the daily and monthly optimum tilt angles for the PV panels. The optimum tilt angles were found to be 0° or 25° depending on the time of the year. From October to February, the optimum tilt angle has been determined to be 0° and, from March to September, the optimum tilt angle is observed to be 25°. There are only two seasonal adjustments that are needed for PV solar panels in Zomba district and these should be carried out at the end of February and at the end of September. For fixed solar panels with no seasonal adjustments, the optimum tilt angle for the PV solar panels that are northfacing has been determined to be 25°. 1. Introduction Non-renewable energy sources, such as fossil fuel, have been the major source of energy in many countries, including Malawi. But because of the problems associated with the use of these non renewable energy sources, there is a need for alternative energy sources that are sustainable and nonpolluting. Kalogirou [1] observed that solar energy offers one of the best solutions to the problem of climate change. It also offers the possibility of reducing high demand for grid electricity and shortage of cooking and heating energy in rural and poor-urban households [2]. Madhlopa [3] further observed that Malawi has abundant solar radiation for most of the year. There are several ways in which solar energy is being used, either directly or indirectly [4]. For direct usage, solar energy can be used as thermal energy or indirectly by converting it into electrical energy using photovoltaic systems. For larger, utility-scale applications, solar energy can feed vast photovoltaic (PV) solar panel farms or can be concentrated to vaporize fluids or to run heat engines [5]. Photovoltaic (PV) solar panels are used to convert solar radiation directly into electricity. Among the many renewable energy alternatives, solar energy remains one of the most well-known and adaptable methods for producing heat and electricity [1]. The conversion of solar energy into electricity by the solar panels is affected by, amongst other factors, absorption
The Disagreement between Anisotropic-Isotropic Diffuse Solar Radiation Models as a Function of Solar Declination: Computing the Optimum Tilt Angle of Solar Panels in the Area of Southern-Italy  [PDF]
Emanuele Calabrò
Smart Grid and Renewable Energy (SGRE) , 2012, DOI: 10.4236/sgre.2012.34035
Abstract: In this paper a simulation to maximize the global solar radiation on a sloped collecting surface was applied to typical latitudes in the area of southern Italy, to calculate the optimum tilt angle of solar panels on building structures or large photovoltaic power plants located in that geographical area. Indeed, the area of southern Italy and in particular Sicily and Calabria are the top of European locations for acquiring solar energy. Some models of diffuse solar irradiance were taken into account to determine panels inclinations that maximized the impinging solar radiation by means of global horizontal solar radiation data provided from the Italian Institute of ENEA (Italy). An algorithm was used for the simulation providing a set of tilt angles for each latitude. The optimum tilt angle values obtained from the simulation resulted to be strictly related to the model of diffuse solar radiation that was used. Indeed, the disagreement between the values obtained using anisotropic models of diffuse solar radiation and those obtained from the isotropic model resulted to decrease significantly with increasing solar declination, showing that the isotropic model can be reliable only in summer months.
Output Energy of Photovoltaic Module Directed at Optimum Slope Angle in Kuala Lumpur, Malaysia
Zeinab Abdallah M. Elhassan,Muhammad. Fauzi. Moh. Zain,Kamaruzzaman Sopian,Arafa Awadalla
Research Journal of Applied Sciences , 2012, DOI: 10.3923/rjasci.2011.104.109
Abstract: This research analyzes the optimal choice of the tilt angle for (PV) module sequentially to collect the maximum power. The tilt and slope angles of a Photovoltaic (PV) array affect the amount of occurrence solar radiation exposed on the array. It based on the measured values of daily global and diffuse solar radiation on a horizontal surface which generate the maximum power. It had shown the different optimal angle of tilt (β) for each direction during sunny days per year. To allow to collected the maximum power energy for Kuala Lumpur site on yearly bases. The influences of PV roofing orientation on the power output of PV modules are also investigated. Annual optimum tilt angle is found to be approximately equal to latitude of the location was 15° at South direction. Compared with the different optimum tilt (β) and four directions. Results give implementation for the optimum tilt angles for BIPV applications.
OPTIMIZATION OF TILT ANGLE FOR PHOTOVOLTAIC ARRAY  [PDF]
Ashok Kumar,,N.S.Thakur,,Rahul Makade,,Maneesh Kumar Shivhar
International Journal of Engineering Science and Technology , 2011,
Abstract: The performance of a solar radiation conversion system is affected by its tilt angle with the horizontal plane, thus photovoltaic array need to be tilted at the correct angle to maximize the performance of the System, This paper deals with the determination of optimum tilt angle for solar PV array in order to maximize incident solar irradiance. The model starts by calculating the monthly averaged daily solar irradiation components (direct, diffuse, ground- eflected) absorbed by the solar PV array of varying tilt, for this purpose Khatkar Kalan (Punjab ) is selected (latitude=31.06) where the photovoltaic arrays are installed. It is found that the optimum tilt angle changes between 60.5 (January) and 62.5 (December)throughout the year. In winter (December, January, and February) the tilt should be 57.48 , in spring (March, April, and May) 18.16 , in summer (June, July, and August) 2.83 , and in autumn (September,October, and November) 43.67 . The yearly average of this value was found to be 30.61 which is nearly equal to the angle selected at Khatkar Kalan.
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