• Energy Research

In the present study, degradation analysis of two System of 20 poly-crystalline silicon PV module are investigated. This study reports data collected from 20 distinct poly-crystalline modules deployed at two cities with different weather conditions. The first system is installed in Casamance (Senegal), and the second one in Cologne (Germany). After a few years exposition in outdoor, a comprehensive analysis has been carried out through visual inspection, infrared thermal imaging and I-V characteristic. The global degradation of the power output (Pmax) has been measured to be from 8.75%/year to 22.45%/year in Casamance and 0.8%/year to 1,4%/year in Cologne. The following degradation mechanism have been detected: delamination (corrosion), hot-spot, soiling and cell crack.

In the current economic, energy and environmental context, the implementation of technologies using renewable energies as a source of power electricity and cooling production is very beneficial insofar as it allows the reduction of pollution and the cost of fossil fuels. Senegal has a sunshine potential well distributed across the country for irradiation varying from South to North between 1850 KWh/m²/year and 2250 kWh/m²/year. It is one of the best solar potentials in the world. Systems operating on the organic Rankine cycle ORC and the absorption cooling system ACS are innovative and sustainable technologies for the exploitation of low enthalpy renewable energy sources. In this present work, the thermodynamic analysis of a combined ORC and ACS system for power electricity and cold production is carried out numerically using the Engineering Equation Solver (EES) software. R245fa and water-lithium bromide mixture are used as working fluid for ORC and ACS respectively. The results obtained at the ACS subsystem level show that the COP of ACS decreases when the absorption temperature increases. This reduction goes from 0.83 to 0.55, i.e. a reduction of 0.28 for a variation of absorption temperature from 27°C to 45°C. The COP has stabilized for generator temperatures above 95°C and is in the range of 0.7 to 0.8. These fluctuations are due to the irreversibility at the level of the components of the system. For the ORC subsystem, the turbine power and ORC condenser power decrease as the ORC condensing pressure increases. Thus, the turbine power goes from 235 kW to 200 kW and the ORC condenser power goes from 80 kW to 60 kW.

In this work, recent advances in various silicon nanostructures used in crystalline silicon solar cells for antireflection and light trapping are reviewed. Simulations and optimizations are also performed for the most relevant of these nanostructures. The results showed that nanocones and nanoparaboloids outperform nanopillars and give almost the same antireflective performance, reducing the average reflectance of the crystalline silicon surface below 2% in the wavelength range 300-1100 nm and under normal incidence. This reflectance is also found to stay below 4% for angles of incidence lower than 60° and for the averaged s and p light polarization. As a result, short-circuit current densities of 41.62 and 41.96 mA/cm², can be expected for a silicon solar cell decorated with these two nanostructures, respectively. Finally, we described the formation of silicon nanocones via nanowires by metal assisted chemical etching.

Abstract In this study, consumer type multicrystalline modules are investigated. To assess the long-term reliability of photovoltaic (PV) multicrystalline modules, extended thermal cycling and damp heat testing were performed. This study focused on four multicrystalline modules. Two modules were subjected to 85 °C/85% damp heat testing at 1000 h and 1300 h, respectively. The other two modules were subjected to thermal cycle test of 55 cycles and 66 cycles, respectively. After testing, all 4 solar panels were investigated with the help of visual inspection, thermography, electroluminescence and IV-curve measurements. The main degradations observed were corrosion, hot spot and delamination.

In this work, undoped and Mn doped Pb(Zn1/3Nb2/3)O3-4.5PbTiO3 nanoparticles were dispersed in biopolymer and in mixed biopolymer + pentacene as active layer and deposited by spin coating on ITO glasses. Morphological, optical and electrical properties of these layers were investigated. SEM images show the superposition of different deposited layers ITO/TiO2/PZN-PT-np-biopolymer on glass substrate with thicknesses of 1.600 μm, 1.505 μm and 1.765 μm respectively. The absorbance value in UV visible for pentacene layer increases from 75 % to 99 % while the transmittance for ITO glasses diminishes from more than 80 % to 2 %. Optical gaps of ITO, TiO2, PZN-PT nanoparticles are respectively 3.75 eV, 3.2 eV and 3.15 eV. Pentacene deposition reduced the gap to 1.65 eV for undoped sample and 1.60 eV for the doped ones. Intermediate gaps (2.3 eV and 2.6 eV for undoped sample and 2.15 eV and 2.7 eV for doped sample) were observed. Photoluminescence performed between 450 nm and 750 nm confirms « these intermediate gaps ».