Al-Khwarizmi Engineering Journal Al-Khwarizmi Engineering Journal,Vol. 11, No. 2, P.P. 62- 73 (2015) Temperature Effect on Photovoltaic Modules Power Drop Qais Mohammed Aish Institute of Technology/ Baghdad Email: Abdgold171@yahoo.com (Received 20 February 2014; accepted 25 January 2015) Abstract In order to determine what type of photovoltaic solar module could best be used in a thermoelectric photovoltaic power generation. Changing in powers due to higher temperatures (25 o C, 35 o C, and 45 o C) have been done for three types of solar modules: monocrystalline , polycrystalline, and copper indium gallium (di) selenide (CIGS). The Prova 200 solar panel analyzer is used for the professional testing of three solar modules at different ambient temperatures; 25 o C, 35 o C, and 45 o C and solar radiation range 100-1000 W/m 2 . Copper indium gallium (di) selenide module has the lowest power drop (with the average percentage power drop 0.38%/ o C) while monocrystalline module has the highest power drop (with the average percentage power drop 0.54%/ o C), while polycrystalline module has a percentage power drop of 0.49%/ o C. Keywords: Energy gap, PV modules, PV power, Temperature dependence. 1. Introduction Photovoltaics, or solar panels that produce electricity, are affected by their operating temperature, which is primarily a product of the ambient air temperature as well as the level of sunlight. The pronounced effect that the operating temperature of a photovoltaic (PV) cell/module has upon its electrical efficiency is well documented. There are many correlations expressing Tc, the PV cell temperature, as a function of weather variables such as the ambient temperature, Ta, and the local wind speed, Vw, as well as the solar radiation flux/irradiance, GT, with material and system-dependent properties as parameters, e.g., glazing-cover transmittance, τ, plate absorptance, α etc [1] . An equally large number of correlations expressing the temperature dependence of the PV module‟s electrical efficiency, ƞc, can also be retrieved, although many of them assume the familiar linear form, differing only in the numerical values of the relevant parameters which, as expected, are material and system dependent. Many correlations in this category express instead the module‟s maximum electrical power, Pm, which is simply related to τc through the latter‟s definition (ƞc = Pm (under standard test conditions; 25 o C and GT=1000 w/m 2 ) /AGT), with A being the aperture area), and form the basis of various performance rating procedures. 2. PV Power Output Dependence on Module Operating Temperature The prediction of PV module performance in terms of electrical power output in the field, that is, the deviation from the standard test conditions reported by the manufacturer of the module. For example, a recently proposed correlation for PV power is in which τpv is the transmittance of the PV cells outside layers [2a,b]. A number of correlations found in the literature for PV electrical power as a function of cell/module operating temperature and basic environmental variables. Many of them are linear, while others Qais Mohammed Aish Al-Khwarizmi Engineering Journal, Vol. 11, No. 2, P.P. 62- 73 (2015) 63 are more complex, such as the following nonlinear multivariable regression equation [3] , 𝑃𝑚𝑝 = 𝑑1 + 𝑑2𝑇𝑐 + 𝑑3 [ln 𝐺𝑇 ] 𝑚 𝑑4𝑇𝑐 [ln 𝐺𝑇 ] 𝑚 …(1) resulting from an analysis which addresses the fact that the cells within a module are not identical. (Here, dj, j = 1–4 and m are model parameters.) Another unusual nonlinear correlation [4] gives a correction coefficient for the output power of a water cooled PV system, namely. 𝑃 = 𝑉𝑐 𝑇𝑐 [1 − 𝐺𝑇 −500 2∗10−4 + 𝐶𝑇𝑐 4∗104 50 − 𝑇𝑐 ) 2 …(2) In which Vc and Ic are the output voltage and current, respectively, while the parameter CTc takes values 1 or 3, for values of Tc below or above 50 o C, respectively. With regard to the wind‟s indirectly beneficial effect of lowering the operating temperature by forced convection and, thus, increasing the power output of the modules, the available model [5], is of the form: 𝑃 = 𝐺𝑇 𝑏1 + 𝑏2𝐺2 + 𝑏3𝑇𝑎 + 𝑏4𝑉𝑓 …(3) In this nonlinear equation, Vf is the free-stream local wind speed, i.e., it is measured at a height of 10 m above ground, and the regression coefficients bj, j = 1–4 are determined using solar radiation flux values above 500 W/m 2 [6]. The steady-state power balance determines cell temperature: the input is the absorbed luminous power, which is partially converted into useful electrical output and the rest is dissipated into the surroundings. Convection is the main mechanism for heat dissipation in terrestrial, flat plate applications, and radiation is the second non- negligible mechanism of heat dissipation. A common simplifying assumption is made that the cell-ambient temperature drop increases linearly with irradiance. The coefficient depends on module installation, wind speed, ambient humidity and so on, though a single value is used to characterize a module type [7]. This information is contained in the Nominal Operating Cell Temperature (NOCT), which is defined as the cell temperature is measured under open-circuit when the ambient temperature is 20◦C, irradiance is 0.8 kW/m 2 and wind speed is 1 m/s. TNOCT usually values around 45°C. For variations in ambient temperature and irradiance the cell temperature (in o C) can be estimated quite accurately with the linear approximation [8]; 𝑇𝑐 = 𝑇𝑎 + 𝑇𝑁𝑂𝐶𝑇 −20 0.8 𝑘𝑊/𝑚 2 𝐺𝑇 …(4) Solar panels work best in certain weather conditions, but since the weather is always changing and as engineers are installing solar panels all over the world in different climate regions, most panels do not operating under ideal conditions. That is why it is important for engineers to understand how panels react to different weather conditions. With this knowledge, they can design ways to improve the efficiency of solar panels that operate in non-optimal conditions. In some cases, they design cooling systems to keep the panels within certain temperatures. For example, solar power plants in extremely hot climates may pass a cool liquid behind the panels to pull away heat and keep the panels cool. This is similar to how your body might sweat as a way to stay cool if you were on that run in the 110 ºF air temperature [8]. While it is important to know the temperature of a solar PV panel to predict its power output, it is also important to know the PV panel material because the efficiencies of different materials have varied levels of dependence on temperature. Therefore, a PV system must be engineered not only according to the maximum, minimum and average environmental temperatures at each location, but also with an understanding of the materials used in the PV panel. The temperature dependence of a material is described with a temperature coefficient. For polycrystalline PV panels, if the temperature decreases by one degree Celsius, the voltage increases by 0.12 V so the temperature coefficient is 0.12 V/C. Effect of temperature on module output relative to standard condition (Tc=25 o C and GT= 1000 W/m 2 ) is available in Fig.1 Fig. 1. The effects of a negative temperature coefficient of power on PV module performance [9]. Qais Mohammed Aish Al-Khwarizmi Engineering Journal, Vol. 11, No. 2, P.P. 62- 73 (2015) 64 3. Experimental Measurements Three types of photovoltaic solar cells are selected to study temperature effect on the output power drop of the solar modules: 1. Monocrystalline cells are cut from a single crystal of silicon- they are effectively a slice from a crystal. In appearance, it will have a smooth texture and you will be able to see the thickness of the slice. These are the most efficient and the most expensive to produce [10]. They are also rigid and must be mounted in a rigid frame to protect them (see Fig.2). Fig. 2. Monocrystalline panel. 2. Polycrystalline (or Multicrystalline) cells are effectively a slice cut from a block of silicon, consisting of a large number of crystals. They have a speckled reflective appearance and again you can you see the thickness of the slice [10]. These cells are slightly less efficient and slightly less expensive than monocrystalline cells and again need to be mounted in a rigid frame (see Fig. 3). Fig. 3. Polycrystalline panel. 3. Copper indium gallium (di) selenide (CIGS) is a I-III-VI2 semiconductor material composed of copper, indium, gallium, and selenium. The material is a solid solution of copper indium selenide (often abbreviated "CIS") and copper gallium selenide[10]. It has a chemical formula of CuInxGa (1-x)Se2 where the value of x can vary from 1 (pure copper indium selenide) to 0 (pure copper gallium selenide). CIGS is a tetrahedrally bonded semiconductor, with the chalcopyrite crystal structure, and a band gap varying continuously with x from about 1.0 eV (for copper indium selenide) to about 1.7 eV (for copper gallium selenide)(see Fig.4). Among many uses, CIGS is best known as an alternate solar cell material in thin-film solar cells[10]. In this role, CIGS has the advantages of being able to be deposited on flexible substrate materials, producing highly flexible, lightweight solar panels. Improvements in efficiency have made CIGS a leader among alternative cell materials. Fig. 4. Copper indium gallium (di) selenide (CIGS). 3.1. Experimental Procedure The Prova 200 solar panel analyzer (Fig.5) is used for the professional testing and maintenance of solar panels and modules. In addition to maintenance and installation of solar panels, the Prova 200 solar panel analyzer can be used in the manufacturing and research of solar panels and cells. Table 1 provides the general specification of Prova 200. The portability of this device means that it is also 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 efficiencies are also easily determined using the unit. Prova 200 have a software supply by http://en.wikipedia.org/wiki/Alkali_metal http://en.wikipedia.org/wiki/Group_3_element http://en.wikipedia.org/wiki/Group_6_element http://en.wikipedia.org/wiki/Semiconductor_material http://en.wikipedia.org/wiki/Copper http://en.wikipedia.org/wiki/Indium http://en.wikipedia.org/wiki/Gallium http://en.wikipedia.org/wiki/Selenium http://en.wikipedia.org/wiki/Solid_solution http://en.wikipedia.org/wiki/Tetrahedral http://en.wikipedia.org/wiki/Chemical_bond http://en.wikipedia.org/wiki/Chalcopyrite http://en.wikipedia.org/wiki/Bandgap http://en.wikipedia.org/wiki/Solar_cell http://en.wikipedia.org/wiki/Copper_indium_gallium_selenide_solar_cells http://en.wikipedia.org/wiki/Copper_indium_gallium_selenide_solar_cells Qais Mohammed Aish Al-Khwarizmi Engineering Journal, Vol. 11, No. 2, P.P. 62- 73 (2015) 65 manufacturing company to calibrate the device automatically. This process is done periodically the device is connect with the internet. Fig. 5. The Prova 200 solar panel analyzer. Table 1, General Specifications of Prova 200. Battery type Rechargeable, 2500mAh(1.2V)*8 AC Adaptor AC 110V or 220V input DC 12V / 1~3A output Dimension 257(L) * 155(W) *57(H) mm Weight 1160g / 40 Ooz Operation environment 0 o C ~ 50 o C,85% RH Temperature coefficient 0.1% of full scale/ C (<18C or >28C) Storage environment -20C ~ 60C ,75%C accessories User manual * 1, AC adaptor*1 Optical USB cable*1 Software CD *1, software manual *1 Kelvin clips( 6A max) *1 set 3.1.1. Connecting Wires (Connectors) The terminals of the solar cell are connected as in Fig.6. In this work, the system of measurements is consists of silicon solar cell as it is presented in Fig.4. Fig.4 shows the set-up of our experiment. It is based on the simple solar-cell experiment. Table 2 gives the general specification of this cell. Fig. 6. Wires connections. Table 2, Solar modules specifications. Module type Area, m 2 Voc, V Isc, A Peak power , w Peak voltage , v Peak current , A Energy gap, eV Production date CIGS 0.03 11 0.33 1.8 6.6 0.28 1.35 2013 Monocrystalline 0.36 19.5 2.8 35 15.8 2.3 1.12 2013 Polycrystalline 1 22 8.1 130 18.5 6.0 1.75 2013 3.1.2. Solar panel Parameters Measure The main parameters that characterize a photovoltaic panel (Fig.4) are: 1. Short circuit current (ISC): the maximum current provided by the panel when the connectors are short circuited. 2. Open circuit voltage (VOC): the maximum voltage that the panel provides when the terminals are not connected to any load (an open circuit). 3. 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 not to forget 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 . Qais Mohammed Aish Al-Khwarizmi Engineering Journal, Vol. 11, No. 2, P.P. 62- 73 (2015) 66 4. Fill factor (FF): the relation between the maximum power that the panel can actually provide and the product ISC .VOC. This gives you 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. 5. 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). Considering the definitions of point of maximum power and the fill factor we see that: 𝜂= Pmax/PL= FF.Isc.Voc / PL … (6) The prova 200 experimental measurement steps are as follow: 1- Connect the solar panel solar panel as in Fig.6 2- Connect the solar panel terminal T1 and T2 with the prova 200 device (Kelvin clip connection) as in Fig. 6 3- Input the value of surface area in square meters of the panel and the measured values of solar radiation intensity in W/m 2 4- The measurements is made at a sunny day and at different time intervals of the day so as to get the adjusted values of solar radiation intensity (100, 200, 300, 400, 500, 600, 700, 800, 900, and 1000 W/m 2 and solar cell temperatures (25 o C, 35 o C, and 45 o C). 5- Prova 200 will be made auto scanning at a variable load in ohm (0 to ∞) 6- Prova 200 output are: Voltage (Vnow), Open circuit voltage (VOC), Short circuit current (ISC), , Maximum power point (Pmax), Maximum current (Imax), Maximumvotage (V max ), Fill factor (FF), and Efficiency (𝜂). 4. Results and Discussion The measuring results of the commercial available solar cells from different manufacturers are presented. Cell samples have been investigated regarding their I-V characteristics at different solar intensities in a range 100-1000 W/m 2 and the ambient temperature between (25 o C, 35 o C, and 45 o C). All the measurements and the characteristics of these cells have been made within the date of September and November 2013. The data obtained for I-V characteristics and P-V curve for three types of solar modules; monocrystalline, polycrystalline and copper indium gallium (di)selenide under the specific solar radiation intensities (100-1000 W/m 2 ) and ambient temperatures, 25 o C,35 o C, and 45 o C are shown in Tables 3 to 5. Solar cells powers vary under temperature changes. The change in temperature (increasing values) will affect the power output from the cells (Because of the problem of loss of electricity as a result of heat buildup and non-ideal behavior of semiconductor with the corresponding temperature increase). The voltage is highly dependent on the temperature and an increase in temperature will decrease the voltage. Equation 1, Equation 2 and Equation 3 repent the relationship between solar module power and other environment parameters (solar radiation G, ambient temperature Ta, solar module temperature Tc; which is strongly function with ambient temperature Ta(see Equation 4), and wind speed vf). Fig.7a,Fig.8a, and Fig.9a show the effect of temperature on I-V characteristic of three PV modules at constant solar radiation(1000 W/m 2 ) and different ambient temperatures; 25 o C,35 o C, and 45 o C . With decreasing temperatures, PV currents decrease slightly but PV voltage increase clearly to the all corresponding PV module. As Fig.7b, Fig.8b, and Fig.9b indicate, output powers of photovoltaic modules increase with decreasing the selected temperatures (i.e. 25 o C, 35 o C, and 45 o C). However, Copper indium gallium (di)selenide has the lowest power drop (with the average percentage power drop 0.38%/ o C) while monocrystalline has the highest power drop (with the average percentage power drop 0.54%/ o C) according to the tabulated power values in Tables 3,4, and 5). The percentage of power drop of polycrystalline module is 0.49%/ o C). Radziemska [11] found for the monocrystalline module that the average output power drop is equal to 0.66%/ o C. It has been found that the maximum power density of the two modules decreases with increasing module temperature, where the maximum power density of the mono-crystalline and the poly-crystalline modules for temperature=10 o C was 43.4 mW/cm 2 and 48.76 mW/cm 2 , respectively. Increasing the temperature to 50 o C causes the decrease of the power by 25% and 14% to reach values 36.32 mW/cm 2 and 41.88 mW/cm 2 respectively [12]. This results of ref[11] agrees with proposed results that monocrystalline module has the largest values of power drop as compared with polycrystillane module. One should expect any device utilizing semiconductors to be quite sensitive to Qais Mohammed Aish Al-Khwarizmi Engineering Journal, Vol. 11, No. 2, P.P. 62- 73 (2015) 67 temperature deviations from normal operating temperatures, and solar cells are no exception. An increase in the operating temperature of a solar cell (or the corresponding ambient temperature) typically has the effect of slightly increasing the cell's short-circuit current and significantly decreasing the cell voltage. Therefore, as the temperature of the solar cell rises, the result is that the maximum efficiency decreases (the area of the power rectangle under the VI curve decreases). Table 3, CIGS electrical measured data at different solar intensities (100-1000 W/m 2 ) and different temperatures, 25 o C, 35 o C, and 45 o C. FF % ɳ Imax A Vmax v Pmax w ISC A Voc v Vnow v T o C G w/m 2 0.67 8.63 0.026 7.12 0.19 0.030 9.22 9.42 25 100 0.654 7.85 0.027 6.76 0.188 0.032 8.76 9.332 35 0.619 6.125 0.028 6.425 0.183 0.0347 8.545 9.866 45 0.66 8.51 0.040 7.48 0.298 0.046 9.41 9.44 25 200 0.645 5.689 0.038 7.233 0.278 0.045 9.01 9.21 35 0.630 4.175 0.0362 6.921 0.250 0.0439 9.058 9.048 45 0.65 8.43 0.078 7.41 0.583 0.090 9.81 9.84 25 300 0.64 6.34 0.061 7.19 0.443 0.076 9.561 9.571 35 0.650 4.586 0.059 6.985 0.412 0.0682 9.309 9.315 45 0.64 7.73 0.092 7.31 0.678 0.105 9.91 9.92 25 400 0.639 5.471 0.072 7.201 0.521 0.095 9.567 9.435 35 0.633 4.033 0.067 7.182 0.484 0.0791 9.359 9.362 45 0.63 7.30 0.117 7.17 0.843 0.133 10.01 10.04 25 500 0.649 6.54 0.105 7.166 0.758 0.122 9.893 9.89 35 0.650 4.967 0.104 7.158 0.745 0.119 9.606 9.372 45 0.61 7.30 0.140 6.93 0.970 0.157 10.09 10.11 25 600 0.6211 6.235 0.117 7.102 0.837 0.143 9.78 9.78 35 0.639 4.584 0.112 7.328 0.825 0.134 9.618 9.587 45 0.59 6.4 0.150 6.92 1.093 0.173 10.12 10.14 25 700 0.604 5.89 0.141 6.988 0.989 0.166 9.78 9.43 35 0.622 4.600 0.137 7.047 0.966 0.160 9.656 8.730 45 0.57 6.23 0.170 6.73 1.146 0.196 10.18 10.20 25 800 0.611 5.67 0.154 6.76 1.042 0.178 9.98 9.71 35 0.615 4.084 0.144 6.780 0.980 0.165 9.619 9.596 45 0.55 6.14 0.186 6.58 1.229 0.217 10.22 10.23 25 900 0.596 5.43 0.172 6.863 1.186 0.201 9.897 10.01 35 0.618 4.220 0.165 6.902 1.139 0.190 9.674 9.972 45 0.52 6.06 0.217 6.42 1.394 0.256 10.36 10.37 25 1000 0.567 5.246 0.197 6.642 1.310 0.237 10.01 9.36 35 0.582 4.188 0.182 6.883 1.254 0.215 9.995 8.428 45 Qais Mohammed Aish Al-Khwarizmi Engineering Journal, Vol. 11, No. 2, P.P. 62- 73 (2015) 68 Table 4, Moncrystaline electrical measured data at different solar intensities (100-1000 W/m 2 ) and different temperatures, 25 o C, 35 o C, and 45 o C. FF Ƞ % I max A Vmax v Pmax w Isc A Voc v Vnow v T 0 C G w/m 2 0.48 4.21 0.131 11.7 1.5 0.196 16.19 16.2 25 100 0.521 6.74 0.196 11.88 2.34 0.256 15.69 15.98 35 0.568 8.322 0.25 11.94 2.966 0.339 15.55 15.43 45 0. 61 5.54 0.299 13.58 4.04 0.383 17.4 17.42 25 200 0.621 5.893 0.32 12.92 4.16 0.413 16.68 16.58 35 0.637 6.393 0.373 12.31 4.603 4670. 15.70 15.79 45 0.65 5.90 0.426 14.4 6.52 0.556 17.94 17.99 25 300 0.645 4.78 0.458 13.55 6.21 0.52 16.567 16.59 35 o.636 4.7.5 0.403 12.59 5.o82 0.5 15.97 16.05 45 0.67 6.53 0.693 14.63 10.1 0.825 18.18 18.2 25 400 0.6632 6.34 0.697 14.01 9.77 0.805 17.409 17.94 35 0.65. 5.733 0.626 13.18 8.256 0.764 16.61 16.64 45 0.79 6.42 0.73 14.71 12.6 0.972 18.25 18.3 25 500 0.734 6.432 0.820 13.69 11.23 0.989 17.54 17.345 35 0.676 6.454 0.870 13.34 11.61 1.028 16.69 16.72 45 0.69 6.37 0.952 14.81 14.1 1.106 18.36 18.4 25 600 0.689 6.034 0.921 14.21 13.10 1.118 17.643 17.89 35 0.680 5977 0.954 13.52 12.91 1.127 16.83 16.85 45 0.69 6.23 1.06 15.03 15.97 1.23 18.49 18.5 25 700 0.684 6.196 1.04 14.98 15.63 1.278 17.567 17.98 35 0.682 6.188 1.154 13.59 15.59 1.342 17.02 17.04 45 0.7 7.3 1.4 15.3 21.5 1.62 18.79 18.8 25 800 0.697 6.45 1.33 14.76 19.74 1.56 18.045 17.694 35 0.685 5.853 1.238 13.61 16.85 1.439 17.08 17.09 45 0.7 6.9 1.507 15.2 22.9 1.71 18.88 18.89 25 900 0.69 6.56 1.39 14.56 20.33 1.687 17.578 17.67 35 0.686 6.020 1.426 13.67 19.50 1.658 17.13 17.11 45 0.71 7.2 1.72 15.4 26.4 1.95 19.05 19.05 25 1000 0.689 6.84 1.625 14.63 23.78 1.934 18.49 18.56 35 0.687 6.323 1.684 13.51 22.67 1.928 17.16 17.15 45 Qais Mohammed Aish Al-Khwarizmi Engineering Journal, Vol. 11, No. 2, P.P. 62- 73 (2015) 69 Table 5, Polycrystalline electrical measured data at different solar intensities (100-1000 W/m 2 ) and different temperatures, 25 o C, 35 o C, and 45 o C. FF Ƞ % Imax A Vmax V Pmax W Isc A Voc V Vnow V T 0 C G w/m 2 0.66 13.92 0.8 17.40 13.92 1.2 17.5 17.6 25 100 0.723 14.054 0.85 16.32 13.88 1.15 17.89 18.54 35 0.758 14.90 0.931 15.89 14.88 1.050 18.69 19.31 45 0.81 14.00 1.600 17.50 28.00 1.800 19.00 19.10 25 200 0.788 10.48 1.39 16.88 23.54 1.76 18.998 19.04 35 0.766 9.221 1.135 16.23 18.42 1.720 18.91 18.91 45 0.82 10.5 2.4 17.52 42.05 2.5 20.50 20.50 25 300 0.794 9.78 1.995 16.922 33.761 2.32 20.056 19.78 35 0.755 9.480 1.752 16.21 28.41 1.905 19.23 19.23 45 0.78 12.8 2.9 17.7 51.3 3.1 21.00 21.01 25 400 0.778 11.34 2.371 17.21 40.81 3.067 20.67 20.45 35 0.765 9.356 2.295 16.28 37.38 2.513 19.42 19.40 45 0.73 10.98 3.1 17.72 54.9 3.52 21.08 21.09 25 500 0.737 9.65 2.86 17.32 49.60 3 20.862 20.23 35 0.747 8.631 2.569 16.77 43.11 2.965 19.46 19.46 45 0.84 10.6 3.5 17.76 63.9 3.56 21.13 21.14 25 600 0.789 10.34 3.55 17.22 61.22 3.87 20.46 20.78 35 0.758 10.07 3.720 16.22 60.36 4.043 19.67 19.65 45 0.8 10.9 4.3 17.8 76.9 4.5 21.24 21.25 25 700 0.778 9.67 4.367 16.92 73.89 4.456 20.46 20.68 35 0.756 9.202 3.956 16.26 64.35 4.332 19.63 19.61 45 0.77 10.48 4.7 17.84 83.84 5.06 21.39 21.4 25 800 0.765 10.04 4.712 17.35 81.76 5.21 20.56 20.976 35 0.752 9.863 4.906 16.06 78.82 5.332 19.56 19.62 45 0.78 10.49 5.24 18.02 94.42 5.6 21.52 21.51 25 900 0.762 9.678 5.234 17.47 91.442 5.678 20.567 20.47 35 0.753 9.378 5.262 16.04 84.40 5.719 19.59 19.59 45 0.8 10.07 5.5 18.31 100.7 5.8 21.59 21.6 25 1000 0.793 9.67 5.6 17.45 97.87 5.98 20.78 20.68 35 0.746 9.220 5.744 15.95 92.10 6.276 19.65 19.49 45 Qais Mohammed Aish Al-Khwarizmi Engineering Journal, Vol. 11, No. 2, P.P. 62- 73 (2015) 70 Fig. 7a. Output I-V characteristics of the Copper indium gallium (di) selenide with different temperatures and constant solar radiation (1000 W/m 2 ). Fig. 7b. Output P-V characteristics of the Copper indium gallium (di) selenide with different temperatures and constant solar radiation (1000 W/m2). Fig. 8a. Output I-V characteristics of Monocrystalline with different temperatures and constant solar radiation (1000 W/m2). Fig. 8b. Output P-V characteristics of Monocrystalline with different temperatures and constant solar radiation (1000 W/m2). Fig. 9a. Output I-V characteristics of polycrystalline with different temperatures and constant solar radiation (1000 W/m2). Fig. 9b. Output P-V characteristics of polycrystalline with different temperatures and constant solar radiation (1000 W/m2). Qais Mohammed Aish Al-Khwarizmi Engineering Journal, Vol. 11, No. 2, P.P. 62- 73 (2015) 71 5. Conclusions The operating temperature plays a central role in the photovoltaic conversion process. The power outputs of PV modules depend on the operating temperature, decreasing with increasing the ambient temperatures. According to the experimental measurements solar modules powers decrease against temperatures increasing. It became clear that as the temperature raises the power drops. Compare to the experimental measurements, in regard to power drop percentage per temperature vary from module to another, which are for Monocrystalline module > Polycrystalline module > pCopper indium gallium (di)selenide. Notation A ideality factor A aperture surface area of PV module (m 2 ) GT solar radiation flux (irradiance) on module plane (W/m 2 ) P electrical power (W) FF Fill factor G Solar radiation, w/m 2 IL Photocurrent, A Imaxp Imp Maximum Current at Pmax , mA Io Saturation current, A IP Operating current, A Isc Current at short circuit, mA PL Power of Solar radiation, w Pmax Maximum Solar Power, w RL Load resistance, Ω Ta Ambient temperature, o C Tc Cell/module operating temperature , o C TNOCT Nominal operating cell temperature, o C Vmaxp Vmp Maximum Voltage at Pmax, V V Voltage (V) Vf Free stream wind speed (m/s) Vw Wind speed at monitored surface (m/s) Voc Voltage at open circuit, V Greek letters ƞ cell/module electrical efficiency,% τ solar transmittance of glazing Subscripts 0 at SRC a ambient b back side c cell (module) f free stream L loss m maximum, at maximum power point oc open circuit ref reference value, at reference conditions sc short circuit 6. Reference [1] Skoplaki E. and J.A. Palyvos, “On the temperature dependence of photovoltaic module electrical performance: A review of efficiency/power correlations” , Solar Energy 83 , 614–624, 2009. [2-a] Jie, J., Hua, Y., Gang, P., Bin, J., Wei, H.. Study of PV-Trombe wall assisted with DC fan. Building and Environment 42, 3529– 3539, 2007a. [2-b] Jie, J., Hua, Y., Wei, H., Gang, P., Jianping, L., Bin, J.. Modeling of a novel Trombe wall with PV cells. Building and Environment 42,1544–1552, 2007b. [3] Rosell, J.I., Iba´n˜ ez, M.. Modelling power output in photovoltaic modules for outdoor operating conditions. Energy Conversion and Management 47, 2424–2430, 2006. [4] Furushima, K., Nawata, Y., Sadatomi, M.,. Prediction of photovoltaic power output considering weather effects. In: ASES Conference SOLAR 2006 – Renewable Energy Key to Climate Recovery. July 7–13, Denver, Colorado, 2006. [5] Farmer, B.K.,. PVUSA Model Technical Specification for a Turnkey Photovoltaic Power System. 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[10] David Tan Ang Kian Seng „Hand book of solar photovotiac system (PV) systems‟ , Singapore, 2011. [11] Radziemska, E.,” The effect of temperature on the power drop in crystalline silicon solar cells”, Renewable Energy 28, 1–12, 2003. [12] El-Shaer, A., M. T. Y. Tadros, M. A. Khalifa,” Effect of Light intensity and Temperature on Crystalline Silicon Solar Modules Parameters”, International Journal of Emerging Technology and Advanced Engineering, Volume 4, Issue 8, August 2014. (2015) 62- 73، صفحة 2، العذد11دالخىارزمً الهنذسٍة المجلجلة م قٍس محمذ عاٌص 73 الخالٌا الشمسٍة تأثٍر درجة الحرارة على انخفاض قذرة وحذات شقٍس محمذ عاي بغذاد / الىجٍوهعهذ الخكي Abdgold171@yahoo.com :البرَذ االلكخروًٍ الخالصة حغُر القذرة ًخُجُت زَبدة درجبث الحرارة . َكىى اسخخذاههب أفضل هع زَبدة درجت الحرارة هي اجل ححذَذ أٌ ًىع هي وحذاث الخالَب الشوسُت (25 o C, 35 o C, and 45 o C) جلُىم والسلٌُبد -أًذَىم -أًىاع هي وحذاث الخالَب الشوسُت وهٍ احبدَت الخبلىر، ثٌبئُت الخبلىر، و ًحبس ةحن اَجبدٍ لثالد درجت 45، و 35، 25: لخحلُل الخالَب الشوسُت لفحص وحذاث الخالَب الشوسُت الثالد وفٍ درجبث حرارة هخخلفت 200لقذ اسخعول جهبز بروفب . الثٌبئٍ فٍ هٍ األقل أًخفبض جلُىم والسلٌُبد الثٌبئٍ -أًذَىم -ًحبسوحذة الخلُت ًىع .واط لكل هخر هربع 1000الً 100ع شوسٍ هئىَت وضوي هذي اشعب /%0.38قذرة o C 0.54 هٍ االعلً احبدَت الخبلىربٌُوب وحذة الخلُت ًىع%/ o C. ٍبٌُوب وحذة الخلُت هخعذدة الخبلىر كبًج ًسبت اًخفبض الفىلخُت ه 0.49%/ o C.