Measured and modelled improvement in solar energy yield from flat plate photovoltaic systems utilizing different tracking systems and under a range of environmental conditions

This work is performed to investigate the effect of using different sun tracking mechanisms on the flat plate photovoltaic system performances and the main parameters affecting the amount of their electrical energy output as well as those affecting their gains compared to the traditional fixed photovoltaic systems. To this end, five configurations of sun tracking systems and two traditional fixed panels have been considered. The sun tracking systems effect on the PV system performances is improved by using the hourly data collected over 18Â days for different seasonal sky conditions. The daily cumulative electrical energy produced by the different systems have been quantified separately for each sky state and the corresponding electrical gains have then been compared to those experienced with two traditional fixed photovoltaic systems. It is found that for a completely clear day, the highest obtained gains are those related to the two-axis sun tracker systems, which decrease gradually from the inclined to the vertical rotating axis when the same optimum slope is applied and from the seasonal to the yearly optimum slope if the same rotating axis is considered. On the other hand, for the partially clear days, the gain amounts are mainly dependant on the clearness index and on the seasonal variation of day length values. For a completely cloudy day, the results show that all considered systems produced closely the same electrical energy and the horizontal position of the photovoltaic panel presented the best performance.

[1]  Salah Abdallah.  The effect of using sun tracking systems on the voltage–current characteristics and power generation of flat plate photovoltaics , 2004 .

[2]  Tian Pau Chang,et al.  Performance study on the east–west oriented single-axis tracked panel , 2009 .

[3]  T. M. Klucher.  Evaluation of models to predict insolation on tilted surfaces , 1978 .

[4]  D. L. King,et al.  Sandia National Laboratories , 2000 .

[5]  L. Alados-Arboledas,et al.  On shadowband correction methods for diffuse irradiance measurements , 1995 .

[6]  A. Hepbasli,et al.  Determination of the optimum tilt angle of solar collectors for building applications , 2007 .

[7]  Gladius Lewis.  Optimum tilt of a solar collector , 1987 .

[8]  Runsheng Tang,et al.  Optical performance of vertical single-axis tracked solar panels , 2011 .

[9]  Leon Jay Gleser,et al.  Assessing uncertainty in measurement , 1998 .

[10]  T. McMahon,et al.  Updated world map of the Köppen-Geiger climate classification , 2007 .

[11]  R. Tang,et al.  Optical performance of inclined south-north single-axis tracked solar panels , 2010 .

[12]  Tian Pau Chang.  The gain of single-axis tracked panel according to extraterrestrial radiation , 2009 .

[13]  Faik Hamad,et al.  Optimum tilt angle for a flat plate solar collector , 1988 .

[14]  Richard C. Neville,et al.  Solar energy collector orientation and tracking mode , 1978 .

[15]  W. Beckman,et al.  Solar Engineering of Thermal Processes , 1985 .

[16]  William A. Beckman,et al.  Improvement and validation of a model for photovoltaic array performance , 2006 .

[17]  D. Ibrahim.  Optimum tilt angle for solar collectors used in Cyprus , 1995 .

[18]  V. H. Morcos.  Optimum tilt angle and orientation for solar collectors in Assiut, Egypt , 1994 .

[19]  M. M. El-Kassaby.  Monthly and daily optimum tilt angle for south facing solar collectors; theoretical model, experimental and empirical correlations , 1988 .

[20]  S. Singer,et al.  Characterization of PV array output using a small number of measured parameters , 1984 .

[21]  Timothy U. Townsend,et al.  A Method for Estimating the Long-Term Performance of Direct-Coupled Photovoltaic Systems , 1989 .

[22]  A. Q. Malik,et al.  Optimum tilt angle and orientation for solar collector in Brunei Darussalam , 2001 .

[23]  Wei Zhou,et al.  A novel model for photovoltaic array performance prediction , 2007 .

[24]  J. P. Chiou,et al.  Optimum slope for solar insolation on a flat surface tilted toward the equator in heating season , 1986 .

[25]  James E. Braun,et al.  Solar geometry for fixed and tracking surfaces , 1983 .

[26]  K. Gopinathan.  Solar radiation on variously oriented sloping surfaces , 1991 .

[27]  M. Iqbal,et al.  Optimum collector slope for residential heating in adverse climates , 1979 .

[28]  N. A. Kelly,et al.  Improved photovoltaic energy output for cloudy conditions with a solar tracking system , 2009 .

[29]  M. Kacira,et al.  Determining optimum tilt angles and orientations of photovoltaic panels in Sanliurfa, Turkey , 2004 .

[30]  Mourad Haddadi,et al.  Apport énergétique de la poursuite solaire sur deux axes par rapport aux systèmes fixes. Application aux capteurs plans , 2007, Journal of Renewable Energies.

[31]  Mazen M. Abu-Khader,et al.  Evaluating multi-axes sun-tracking system at different modes of operation in Jordan , 2008 .

[32]  S.Sh. Soulayman.  On the optimum tilt of solar absorber plates , 1991 .

[33]  Mehmet Akbaba,et al.  A new model for I–V characteristic of solar cell generators and its applications , 1995 .

[34]  Cemil Sungur,et al.  Multi-axes sun-tracking system with PLC control for photovoltaic panels in Turkey , 2009 .

[35]  T. Chang.  Output energy of a photovoltaic module mounted on a single-axis tracking system , 2009 .

[36]  Hamdy K. Elminir,et al.  Optimum solar flat-plate collector slope: Case study for Helwan, Egypt , 2006 .

[37]  Ali Al-Mohamad,et al.  Efficiency improvements of photo-voltaic panels using a Sun-tracking system , 2004 .

[38]  Mark W. Davis,et al.  Short-term characterization of building integrated photovoltaic panels , 2003 .

[39]  P. E. Russell,et al.  Evaluation of power output for fixed and step tracking photovoltaic arrays , 1986 .

[40]  J. Kern,et al.  On the optimum tilt of a solar collector , 1975 .