Electrophysical Properties of Two Structured Polycrystal Silicon

The article first describes the results obtained in the study of the electrophysical and charge transfer processes of two structural polycrystalline silicon obtained by bonding silicon particles with sunlight. The results of the study show that the charge transfer processes in such structures are found to be different from each other. In particular, at T~300-800 K, a decrease in the surface area of both structures µ was observed, and the temperature dependence of p and n differed from each other. For example, (a) in the surface area T~300-350 K and T~600-710 K p increases and n decreases, at T~350-550 K p decreases and n increases. Conversely, the surface area of the sample (b) is characterized by an increase in p and a decrease in n at T≤575 K, a decrease in p in the later stages of temperature increase, and an increase in n.

Microcructure of Polycrystal Silicon Heated by Sunlight

The article describes the method of obtaining polycrystalline silicon by combining silicon particles with sunlight, its microstructure and the mechanisms of formation of intergranular boundary areas. The results of the study show that the microstructure of the surface areas where sunlight falls (a) and does not fall (b) differs from each other. This is explained on the basis of the formation of temperature differences in the surface areas (a) and (b) for the uniform accumulation of silicon particles.

A Study on the Characteristics of the Concentrated Solar Photovoltaic/thermal Integrated System

This paper mainly introduces a comprehensive solar energy utilization system with low-CPC and polycrystalline silicon solar photovoltaic components. Outdoor experiments have been made to test the electrical efficiency, heat efficiency and their changes of the system with fixed temperature of outlet water and different sunshine conditions. Besides, this paper also compares the effects of outlet water at various temperatures on the efficiency of the whole system as well as the temperatures and flow rate responses with different PID parameters. Through analysis of these experimental data, the most desirable temperature of outlet water and PID parameters have been obtained in CPC-PV/T Hybrid Thermal-electric System, thus providing references for relevant experimental research.

Performance characterization of polycrystalline silicon photovoltaic modules installed in Kumasi, Ghana

The focus of this study is on the assessment of the performance of 14 polycrystalline silicon PV modules installed in Kumasi, Ghana after 22 years of field exposure. Visual inspection was carried out to ascertain any observable defects. Current-Voltage performance data was taken using a non-invasive characterization technique able to predict performance at standard test conditions (using TRI-KA and TRI-SEN) followed by Infrared (IR) Imaging tests. The results of the I-V tests showed average Pmax degradation rate of 1.38%/yr for all 14 modules. This is higher than the acceptable limit of (0.7–1.0%/year). In terms of the individual modules, M1 recorded the worst Pmax rate of degradation of 1.74%/yr, and the lowest values for efficiency and fill factor. This is consistent with the IR images and temperature difference that were recorded in the IR tests. A higher temperature difference of 25°C was recorded indicating the presence of a hot spot and a defective cell which was confirmed by the hue white colour observed in the IR test. Power Performance Factor (PPF) range of 61.8–76.5% was recorded which is below the limit of 80% often quoted in warranty statements. The drops in PPF indicate that the modules have degraded.

Performance evaluation of monocrystalline and polycrystalline silicon solar photovoltaic modules under low and high irradiance conditions in Kumasi, Ghana

One of the biggest drawbacks of photovoltaic (PV) for many applications is the uncertainty in the energy output due to losses attributed to efficiency loss at low irradiance levels. In this study, the electrical performance of as received monocrystalline silicon (mono-c-Si) and polycrystalline silicon (poly-c-Si) PV modules were evaluated at high and low irradiance conditions in Kumasi, Ghana using I-V Tracer. The low irradiance level of 200W/m2 was achieved by covering the surface of the PV modules with a calibrated mesh screen. Maximum output power (Pmax) of 87.9 W and 136.7 W were recorded for the mono-c-Si and poly-c-Si modules at high irradiance respectively. The corresponding average values at low irradiance were 8.29 W and 12.13 W representing percentage reductions of 90.57% and 91.60% respectively for the two technologies. These results indicate that when irradiance drops to 200 W/m2 and below, the PV modules generate around only 10% of their nominal output power. This has implications for the number of modules that are required for installation in areas that experience many hours of low irradiance. Efficiency reductions of 64.4% and 59.01% for the mono-c-Si and poly-c-Si modules respectively at low irradiance is reported. The results also indicate that the mono-c-Si is affected more by light induced degradation effect than the poly-c-Si module after a few hours of exposure to the natural light. The novelty of this work is that knowledge of the performance at low irradiance will enable designers determine the number of modules required during the sizing of PV plants.