Study of Temperature Coefficients for Parameters of Photovoltaic Cells

Abstract

The temperature is one of the most important factors which affect the performance of the photovoltaic cells and panels along with the irradiance. The current voltage characteristics, I-V, are measured at different temperatures from 25°C to 87°C and at different illumination levels from 400 to 1000 W/m2, because there are locations where the upper limit of the photovoltaic cells working temperature exceeds 80°C. This study reports the influence of the temperature and the irradiance on the important parameters of four commercial photovoltaic cell types: monocrystalline silicon—mSi, polycrystalline silicon—pSi, amorphous silicon—aSi, and multijunction InGaP/InGaAs/Ge (Emcore). The absolute and normalized temperature coefficients are determined and compared with their values from the related literature. The variation of the absolute temperature coefficient function of the irradiance and its significance to accurately determine the important parameters of the photovoltaic cells are also presented. The analysis is made on different types of photovoltaics cells in order to understand the effects of technology on temperature coefficients. The comparison between the open-circuit voltage and short-circuit current was also performed, calculated using the temperature coefficients, determined, and measured, in various conditions. The measurements are realized using the SolarLab system, and the photovoltaic cell parameters are determined and compared using the LabVIEW software created for SolarLab system.

The Defining Positive Role of High Cell Temperature on the Efficiency of a Multicrystalline Solar Photovoltaic Array

“…In contrast to literature and research papers [1,2,3,4,5,6,7,8,9,10] all which shows DC power efficiency and solar cell conversion efficiency decrease with increase in cell temperature above 25 o C, this paper brings forward for the first time ever the defining positive role of high cell temperature on DC power efficiency and solar cell conversion efficiency. High efficiency is obtained only at high temperature, further efficiency variations are governed by voltage variations and as voltage variations are governed by cell temperature it is the cell temperature that plays the defining positive role on both E 1 and E 2 .…”

“…In summers both E 1 and E 2 increase with increase in POA and increase in cell temperature even as cell temperature increases up to 58. High V dc is obtained only at high cell temperature as mentioned by Garg and JB [14] and is also visible from figures 1,3,5,7,9,12,14,18,20,22,24,26,28  For spring season, the average cell temperature varies between 39-43 o C with average E 1 and E 2 varying between 7.20 to 7.40% and 42.52% to 43.71% respectively.…”

“…Power temperature coefficient of -0.5%/ o C for polycrystalline silicon and -0.25%/ o C for amorphous silicon was reported by King et al while -0.4%/ o C for crystalline silicon was reported by Sick and Erge [6]. Cotfas et al found that power coefficient for different types of cell varied between -0.14% o C to -0.47%/ o C [7]. Kamuyu et al showed that efficiency decreases with increase in temperature and that Floating PV system produce 10% more energy as compared to land-based system due to cooling effect of water [8].…”

“…Literature and several research papers show that both power output and efficiency decrease with increase in temperature [1,2,3,4,5,6,7,8,9,10]. Elminir et al showed that temperature coefficient for current, power and efficiency were about + 40 μA/ o C, -0.4mW/ o C and -0.4%/ o C respectively [2].…”

Determination of Technological Features of a Solar Photovoltaic Cell Made of Monocrystalline Silicon P+PNN+

“…X-ray diffraction is an analytic technique which offers structural and chemical information about the crystallography of a range of various materials [25], such as the crystallographic structure of the material, structural analysis of the material, surface analysis of the material, analysis of thin layers, and transformation due to the influence of temperature (see Figures 4 and 5) [25][26][27]. Graphics data processing was made by the representation of data acquired using a D8 DISCOVER diffractometer, Bruker AXS GmbH.…”