عباس حميد و د.عماد وشيماء Al-Khwarizmi Engineering Journal Al-Khwarizmi Engineering Journal, Vol. 9, No. 2, P.P. 57- 68 (2013) Efficiency Prediction and Performance Characterization of Photovoltaic Solar Panel at Baghdad Climate Conditions Abbas Hamid Sulaymon Emad Talib Hahsim Shaymaa Alaulddin Mahdi Department of Energy Engineering/ College of Engineering / University of Baghdad (Received 17 February 2013; accepted 28 May 2013) Abstract The performance of a solar cell under sun radiation is necessary to describe the electrical parameters of the cell. The Prova 200 solar panel analyzer is used for the professional testing of four solar cells at Baghdad climate conditions. Voltage -current characteristics of different area solar cells operated under solar irradiation for testing their quality and determining the optimal operational parameters for maximum electrical output were obtained. A correlation is developed between solar cell efficiency η and the corresponding solar cell parameters; solar irradiance G, maximum power Pmax, and production date P. The average absolute error of the proposed correlation is 5.5% for 40 data points. The results also show that the new solar panels have the highest efficiency compared with the older ones. Keywords: Solar cell, photovoltaic performance, fill factor, efficiency. 1. Introduction The production of photovoltaic electricity has known in recent years an increasing of interest by a production exceeding 1800 MW throughout the world. This increase was accompanied by a revitalization of researches considered for the optimization of the energy given by solar cells. Nowadays, the world's energy needs are growing steadily. However, the conventional sources of energy are limited. Solar energy such as photovoltaic energy (PV) is the most available energy source which is capable to provide this world’s energy needs. The conversion of sunlight into electricity using solar cells system is worthwhile way of producing this alternative energy. The history of photovoltaic energy started in 1839 when Alexandre-Edmond Becquerel discovered the photovoltaic effect [1]. Photovoltaic system uses various materials and technologies such as crystalline silicon (c-Si), cadmium telluride (CdTe), gallium arsenide (GaAs), chalcopyrite films of copper-indium- selenide (CuInSe2), etc [1]. In solar technology, the main challenge of researchers is to improve solar cells efficiency. Due to this challenge, several investigations have been developed to characterize the solar cells by the determining their parameters [2],[3]. Indeed, it is important to know these parameters for estimating the degree of perfection and quality of silicon solar cells. Solar cell efficiency is an important input parameter in PV-powered product design. Often, only limited space is available for the solar cells to be integrated. Cell efficiency can even become a criterion of principal system feasibility. As a basic parameter, cell efficiency serves as an input in calculating the optimal system configuration, e.g., as a cost related trade-off between the storage unit and its lifetime, PV size and its efficiency, although these calculations are well known for autonomous PV systems, e.g. [4] and finally the demand side with correlated consumption profiles. The objectives of the present paper are to find a functional relationship between solar cell efficiency with the solar cell parameters and characterize the performance of different types of solar cells. Abbas Hamid Sulaymon Al-Khwarizmi Engineering Journal, Vol. 9, No. 2, P.P. 57-68 (2013) 58 2. Output Characteristics of Solar Cells The output characteristics of solar cells are expressed in the form of an I - V curve. A typical I - V curve and the test circuit used are shown in Fig.1 (a,b) [5]. The I-V curve is produced by varying RL (load resistance) from zero to infinity and measuring the current and voltage along the way. The point at which the I-V curve and resistance (RL) intersect is the operating point of the solar cell. The current and voltage at this point are Ip and Vp, respectively. The largest operating point in the square area is the maximum output of the solar cell as it's demonstrated in Fig.2. 3. Experimental Measurements The Prova 200 solar panel analyzer (Fig.3) is used for the professional testing and maintenance of solar panels and modules. Table 1 provides the general specification of Prova 200. In addition to maintenance and installation of solar panels, the Prova 200 solar panel analyzer can be used in the manufacturing and testing the solar panels and cells. The portability of this device is useful in quality assurance at various stages on the production line and can be taken from one location to another. When used in the installation of solar panels, the Prova 200 solar panel analyzer assists in determining the proper inverter size as well as optimum power output position of panels and helps identify defective cells or panels that have worn out over time. The solar panel analyzer also provides the user with current and voltage (I- V) test curves, maximum solar power as well as current and voltage. Solar cell properties are easily determined using the following units: I-V Curve Test for Solar Cell, Single Point I-V Test, Maximum Solar Power (Pmax) search by auto-scan, Maximum Voltage (Vmaxp) at Pmax, Maximum Current (Imaxp) at Pmax, Voltage at open circuit (Voc), Current at short circuit (Isc), I-V curve with cursor, Efficiency (%) calculation of solar panel, Scan delay setting. (0 ~ 9999 msec), Solar panel area setting. (0.001 m2 ~ 9999 m2), Standard light source setting. (10 W/m2 ~ 1000 W/m2), Min. power setting for alarm function, Built-in Calendar Clock, Rechargeable batteries with built-in charging circuit, Optical USB cable for PC and The terminals of the solar cell are connected as shown in Fig.4. In this work, the system is consisted of four silicon solar cells (types A, B, C, and D) of different area as it is presented in Fig.5. Table 2 gives the general specification of these cells. Table 1, General Specifications of Prova 200. Battery type Rechargeable, 2500Ah (1.2V) x 8 AC Adaptor AC 110V or 220V input DC 12V / 1~3A output Dimension 257(L) x 155(W) x 57(H) mm Weight 1160g / 40.0oz (Batteries included) Operation Environment 0 ~ 50, 85% RH Temperature Coefficient 0.1% of full scale / 0C (＜18 or 0C＞28) Storage Environment -20 ~ 60, 75% RH Accessories User Manual x 1, AC adaptor x 1 Optical USB cable x 1 Rechargeable batteries x 8 Software CD x 1, Software Manual x 1 Kelvin Clips (6A max) x 1 set Abbas Hamid Sulaymon Al-Khwarizmi Engineering Journal, Vol. 9, No. 2, P.P. 57-68 (2013) 59 Table 2 Solar Cell Specifications. Fig. 1. (a)Test Circuit (b)The I-V curve. Type Area m2 Voc V Isc A Peak power w Peak Voltage v Peak Current A Production date A 0.023 11 0.33 1.8 6.6 0.28 2010 B 0.228 12 2.2 18 9.0 2.0 1980 C 0.366 19.5 2.8 35 15.8 2.3 1986 D 1 22 8.1 130 18.5 6.0 2010 (a) (b) Abbas Hamid Sulaymon Al-Khwarizmi Engineering Journal, Vol. 9, No. 2, P.P. 57-68 (2013) 60 Fig .2. Square Area is The Maximum Power Output of the Solar Cell. (a) (b) Fig. 3. The Prova 200 Solar Panel Analyzer :(a) Front View (b) Top View. Fig. 4. Wires Connections. IV Plot Abbas Hamid Sulaymon Al-Khwarizmi Engineering Journal, Vol. 9, No. 2, P.P. 57-68 (2013) 61 A B C D Fig.5: Solar Cells Tested type A, B, C and D 4. Solar Panel Parameters Measurements The main parameters that characterize a photovoltaic panel (Fig.5) [4] are: • Short circuit current (ISC): the maximum current provided by the panel when the connectors are short circuited. • Open circuit voltage (VOC): the maximum voltage that the panel provides when the terminals are not connected to any load (an open circuit). • Maximum power point (Pmax): the point where the power supplied by the panel is at maximum, where Pmax = Imax x Vmax. The maximum power point of a panel is measured in Watts (W) or peak Watts (Wp). It is important to know that in normal conditions the panel will not work at peak conditions, as the voltage of operation is fixed by the load or the regulator. Typical values of Vmax and Imax should be a bit smaller than the ISC and VOC. • Fill factorn(FF): the relation between the maximum power that the panel can actually provide and the product ISC. VOC. This gives an idea of the quality of the panel because it is an indication of the type of IV characteristic curve. The closer FF is to 1, the more power a panel can provide. Common values usually are between 0.7 and 0.8. • Efficiency (η): the ratio between the maximum electrical power that the panel can give to the load and the power of the solar radiation (PL) incident on the panel. This is normally around 10-12%, depending on the type of cells (monocrystalline, polycrystalline, amorphous or thin film). The definitions of point of maximum power and the fill factor are: = Pmax/PL=FF . ISC . VOC / PL …(1) 5. Result and Discussion The measuring results of the commercial available solar cells from different manufacturers are presented. Cell samples have been investigated regarding their IV-characteristics at different solar intensities in a range 100-1000 W/m2and the ambient temperature between (22-26 ºC). All the measurements and the characteristics of these cells have been made within the date of February and March 2012. The data obtained for I-V characteristics and P-V curve for the silicon solar cell under the specific solar radiation intensities are shown in Tables 3 to 6. A comparison is done between the cell parameters and performance of the solar cell. Fig.6 shows the dependence of solar cell maximum power with solar radiation intensity for the four solar cell types. According to Fig.7 solar cell type A and D have the high solar output efficiency due to earlier Abbas Hamid Sulaymon Al-Khwarizmi Engineering Journal, Vol. 9, No. 2, P.P. 57-68 (2013) 62 production date as compared the other two types B and C. One can see in Fig. 8 that the variation of fill factor of solar cells B,C, and D fluctuated, increased with maximum power increasing while fill factor of type A decreases with increasing maximum power. Fig. 6. Variation of Solar Cell Maximum Power with Solar Radiation Intensity for the Four Solar Cell Types. Fig. 7. Variation of Solar Cell Efficiency with Solar Radiation Intensity for the Four Solar Cell Types. 0 20 40 60 80 100 120 0 200 400 600 800 1000 M ax im u m p o w er ,P m ax ( w ) Solar radiation intensity ,G (w/m2 ) A B C D 0 2 4 6 8 10 12 14 16 0 200 400 600 800 1000 1200 Ef fi ci en cy , η Solar radiation intensity ,G (w/m2 ) A B C D Abbas Hamid Sulaymon Al-Khwarizmi Engineering Journal, Vol. 9, No. 2, P.P. 57-68 (2013) 63 Fig. 8. Variation of Solar Cell Fill Factor with Maximum Power for the Four Solar Cell Types. 6. Correlation Development In order to find a functional relationship between solar cell efficiency with the corresponding solar cell parameters ; solar irradiance G ,maximum power Pmax and production date P, non-linear regression analysis have been used to available experimental data of solar cell as shown in Tables 3 to 6 . The obtained correlation of the computer software program (statistica) is: η=(A1+A2G)(B1+B2P+B3P2)/(D1+D2(Pmax+D3Pmax2 ))+C1+C2G+C3+C4Pmax+C5Pmax2 … (2) A1= -1.227832 A2= -0.00608 B1=23102.47 B2=-21273.8 B3= 5297.8 C1=-608.795 C2=0.000785 C3=311.7824 C4=-0.166576 C5=0.000844 D1=-0.545443 D2=-0.007904 Correlation coefficient (R) = 0.9777 Table 7 shows the calculated solar cell efficiency and the corresponding percentage error. The average absolute error is 5.5% for 40 data point. Table 3, Solar Cell Type A with Surface Area 0.0237 m2 . G w/m2 Vnow v VOC V ISC mA Pmax W Vmax v Imax mA % FF 100 9.24 9.22 30.6 0.19 7.12 26.7 8.63 0.67 200 9.44 9.41 46.4 0.298 7.48 40.8 8.51 0.66 300 9.84 9.81 90.1 0.583 7.41 78.6 8.43 0.65 400 9.92 9.91 105.5 0.678 7.31 92.8 7.37 0.64 500 10.04 10.01 133.6 0.843 7.17 117.5 7.30 0.63 600 10.11 10.09 157.9 0.970 6.93 140.0 7.03 0.61 700 10.14 10.12 173.2 1.039 6.92 150.0 6.4 0.59 800 10.20 10.18 196.8 1.146 6.73 170.5 6.23 0.57 900 10.23 10.22 217.3 1.229 6.58 186.8 6.14 0.55 1000 10.37 10.36 256.7 1.394 6.42 217.3 6.06 0.52 Abbas Hamid Sulaymon Al-Khwarizmi Engineering Journal, Vol. 9, No. 2, P.P. 57-68 (2013) 64 Table 4, Solar Cell Type B with Surface Area 0.228 m2. G w/m2 Vnow v VOC v ISC mA Pmax W Vmax v Imax mA % FF 100 9.39 9.29 217.3 1.23 7.19 172 5.41 0.61 200 10.09 10.07 458.9 3.02 8.97 337 6.62 0.65 300 10.18 10.16 536.9 3.50 9.14 393 5.2 0.65 400 10.34 10.32 732.6 5.36 9.14 586 5.8 0.70 500 10.40 10.39 823.0 6.16 9.05 680 5.4 0.72 600 10.56 10.54 1086 8.52 8.91 956 6.12 0.75 700 10.65 10.63 1240 9.94 8.75 1130 6.23 0.75 800 10.68 10.67 1300 10.29 8.79 1170 5.64 0.74 900 10.78 10.78 1450 11.58 8.79 1310 5.64 0.73 1000 11.02 11.03 1910 15.20 8.91 1710 6.69 0.72 Table 5, Solar Cell Type B with Surface Area 0.366 m2. G w/m2 Vnow v VOC v ISC mA Pmax W Vmax v Imax mA % FF 100 16.20 16.19 196 1.50 11.70 131 4.21 0.48 200 17.42 17.40 383 4.05 13.58 299 5.54 0.61 300 17.99 17.94 556 6.52 14.40 426 5.90 0.65 400 18.20 18.18 825 10.1 14.63 693 6.53 0.67 500 18.30 18.25 972 12.6 14.71 730 6.42 0.79 600 18.40 18.36 1106 14.1 14.81 952 6.37 0.69 700 18.50 18.49 1230 15.97 15.03 1060 6.23 0.69 800 18.80 18.79 1620 21.5 15.30 1400 7.30 0.70 900 18.89 18.88 1710 22.9 15.20 1507 6.90 0.70 1000 19.05 19.05 1950 26.4 15.40 1720 7.20 0.71 Abbas Hamid Sulaymon Al-Khwarizmi Engineering Journal, Vol. 9, No. 2, P.P. 57-68 (2013) 65 Table 6, Solar Cell Type D with Surface Area 1 m2. G w/m2 Vnow v VOC v ISC mA Pmax W Vmax v Imax mA % FF 100 17.60 17.50 1200 13.92 17.40 800 13.92 0.66 200 19.10 19.00 1800 28.00 17.50 1600 14.00 0.81 300 20.50 20.50 2500 42.05 17.52 2400 10.50 0.82 400 21.01 21.00 3100 51.30 17.70 2900 12.80 0.78 500 21.09 21.08 3520 54.90 17.72 3100 10.98 0.73 600 21.14 21.13 3560 63.90 17.76 3500 10.60 0.84 700 21.25 21.24 4500 76.90 17.80 4300 10.90 0.80 800 21.40 21.39 5060 83.84 17.84 4700 10.48 0.77 900 21.51 21.52 5600 94.42 18.02 5240 10.49 0.78 1000 21.60 21.59 5800 100.70 18.31 5500 10.07 0.80 Table 7, The Calculated Solar Cell Efficiency and the Corresponding Percentage Error. Cell type G 100 200 300 400 500 600 700 800 900 1000 A c 8.7 8.4 8.1 7.8 7.5 7.2 6.7 6.3 6.0 5.7 %E -1.1 1.4 4.2 -5.3 -2.2 -1.9 -4.4 -1.8 2.3 6.6 B c 5.6 5.6 5.6 5.8 5.8 6.0 6.1 6.1 6.1 6.1 %E -3.4 15.5 -7.7 0.8 -7.7 2.0 2.6 -8.2 -8.9 9.1 C c 4.5 5.0 5.7 6.5 6.8 6.9 6.9 6.8 6.8 6.6 %E -6.5 9.6 3.0 0.5 -5.5 -7.9 -11.4 6.2 1.3 7.8 D c 13.5 13.3 12.2 11.6 11.4 11.0 10.5 10.4 10.3 10.4 %E 3.0 5.1 -16.7 9.3 -4.4 -3.6 3.8 1.1 1.8 -3.0 7. Conclusions The performance of a solar cell under sun radiation is necessary to describe the electrical parameters of the cell. Effect of production date on the performance of a photovoltaic solar system was investigated. A correlation is developed between solar cell efficiency and with the corresponding solar cell parameters; solar irradiance G, maximum power Pmax and production date P. The average absolute error of the proposed correlation is 5.5% for 40 data points. The results show that there is a fluctuated in solar cell efficiency with the values of irradiance. Notation A ideality factor FF Fill factor G Solar radiation, w/m2 IL Photocurrent, A Imaxp , Imp Maximum Current at Pmax , mA Io Saturation current, A IP Operating current, A Isc Current at short circuit, mA P Production date PL Power of Solar radiation, w Abbas Hamid Sulaymon Al-Khwarizmi Engineering Journal, Vol. 9, No. 2, P.P. 57-68 (2013) 66 Pmax Maximum Solar Power, w RL Load resistance, Ω Vmaxp , Vmp Maximum Voltage at Pmax, V Voc Voltage at open circuit, V Efficiency, % 8. References [1] Sze, S.M., "Physics of Semiconductor Devices", 2nd Ed., John-Wiley,(1981). [2] King D. L., “Photovoltaic Module and Array Performance Characterization Methods for All System operating Conditions”, Proceeding of NREL/SNL Photovoltaics Program Review Meeting, Lakewood, November 18- 22(1996). [3] Van der Heide A.S.H., Schonecker A., Bultman J.H., and W.C. Sinke, “Explanation of high solar cell diode factors by nonuniform contact resistance”, Progress in photovoltaics, , vol. 13, no1, pp. 3-16(2005). [4] Castaner L. and S.Silvestre, "Modelling PV systems using PSPICE", Wiley and Sons. (2002). [5] Gracia M. C. Alonso, J. M. Ruiz, and F. Chenlo, “Experimental study of mismatch and shading effects in the,” Solar Energy Mater. Solar Cells, vol. 90, no. 3, pp. 329–340, Feb. (2006). [6] Khezzar R, Zereg M, and A Khezzar"Laboratoire de Physique Energetique Appliquee (LPEA)", Universite Hadj Lakhdar, 05000 Batna, Algeria r-khezzar@hotmail.com ,(2008). [7] Wagner A. "Peak-power and internal series resistance measurement under natural ambient conditions" EuroSun conference, 2000 Copenhagen, June 19-22 (2000). mailto:r-khezzar@hotmail.com )2013( 57- 68، صفحة2، العدد9مجلة الخوارزمي الھندسیة المجلد عباس حمید سلیمون 67 التكھن بكفاءة الخلیة الشمسیة وتقییم ادائھا في الظروف الجویة لمدینة بغداد شیماء عالء الدین مھدي عماد طالب ھاشم عباس حمید سلیمون جامعة بغداد/ كلیة الھندسة/ قسم ھندسة الطاقة الخالصة الختبار اربع الواح شمسیة 200 استعمل جھاز محلل اداء الخلیة بروفالقد . اداء الخلیة الشمسیة تحت االشعاع الشمسي ضروري لوصف معالم الخلیةان لخالیا شمسیة مختلفة وتحت تاثیر االشعاع الشمسي تیار -لقد تم فحص خصائص الفولطیة .نوع سیلیكون متعدد التبلور عند الظروف المناخیة لمنطقة بغداد اعلى قدرة ،شدة االشعاع الشمسي: تم ایجاد عالقة بین كفاءة الخلیة مع ما یقبلھا من معامالت الخلیة والتي ھي .لتحدید العوامل المثلى التي تعطي اعلى قدرة ان االلواح الشمسیة حدیثة الصنع اكثر كفاءة من نتائج البحث لقد بینت ، عملیةالربعین نقطة % ٥,٥معدل نسبة الخطأ المطلق یساوي . وتاریخ االنتاج .نظیراتھا قدیمة الصنع