Current Issue : April - June Volume : 2018 Issue Number : 2 Articles : 5 Articles
A natural convection solar tunnel dryer comprising three major units, a solar collector unit, a drying unit, and a vertical bare\nflat-plate chimney, was constructed. No-load tests with a horizontal configuration of air entry into the collector resulted in a\nbidirectional air flow in the dryer. To correct this undesirable situation, an air guide at the collector was incorporated to ensure\nthat air entered in a vertical direction. To investigate its performance, drying experiments with mango were carried out at the\nUniversity of Zambia, Department of Agricultural Engineering. Uncertainties in the parameters measured in the experiment were\nanalysed and quantified. The results showed that, under solar radiation between 568.4 and 999.5W/m2, air temperature of up to\n65.8âË?Ë?C was attained at the collector unit.Theaverage relative humidity values were 30.8%, 6.4%, and 8.4% for the ambient, collector,\nand drying unit, respectively.Under these conditions,mango with an initialmoisture content of 85.5% (wet basis) was dried to 13.0%\n(wet basis) in 9.5 hours. The collector, drying, and pick-up efficiencies were found to be 24.7%, 12.8%, and 35.0%, respectively.The\naverage temperature difference between the chimney air and ambient air was 12.1âË?Ë?C, and this was sufficient in driving the flow of\nair through the dryer....
A conversion efficiency of 20.23% of heterojunction with intrinsic thin layer (HIT) solar cell on 156mm Ã?â?? 156mm metallurgical\nSi wafer has been obtained. Applying AFORS-HET software simulation, HIT solar cell with metallurgical Si was investigated with\nregard to impurity concentration, compensation level, and their impacts on cell performance. It is known that a small amount of\nimpurity in metallurgical Si materials is not harmful to solar cell properties....
We investigated the fabrication of large-area (cm2) nanostructured glasses for solar\ncell modules with hydrophobic and hydrophilic properties using soft lithography and colloidal\nlithography. Both of these techniques entail low-cost and ease of nanofabrication. We explored the use\nof simple 1D and 2D nanopatterns (nanowires and nanocones) and the effect of introducing disorder\nin the nanostructures. We observed an increase in the transmitted light for ordered nanostructures\nwith a maximum value of 99% for wavelengths >600 nm when ordered nanocones are fabricated on\nthe two sides of the solar glass. They produced an increment in the efficiency of the packaged solar\ncell with respect to the glass without nanostructures. On the one hand, the wettability properties\nshowed that the ordering of the nanostructures improved the hydrophobicity of the solar glasses and\nincreased their self-cleaning capacity. On the other hand, the disordered nanostructures improved\nthe hydrophilic properties of solar glasses, increasing their anti-fogging capacity. The results show\nthat by selecting the appropriate nanopattern, the wettability properties (hydrophobic or hydrophilic)\ncan be easily improved without decreasing the efficiency of the solar cell underneath....
Solar photovoltaic (PV) farms currently play a vital role in the generation of electrical\npower in different countries, such as Malaysia, which is moving toward the use of renewable\nenergy. Malaysia is one of the countries with abundant sunlight and thus can use solar PV farms\nas alternative sources for electricity generation. However, lightning strikes frequently occur in the\ncountry. Being installed in open and flat areas, solar PV farms, especially their electronic components,\nare at great risk of damage caused by lightning. In this paper, the effects of lightning currents\nwith different peak currents and waveshapes on grid-connected solar PV farms were determined\nto approximate the level of transient effect that can damage solar PV modules, inverters and\ntransformers. Depending on the location of the solar PV farm, engineer can obtain information\non the peak current and median current of the site from the lightning location system (LLS) and\nutilise the results obtained in this study to appropriately assign an SPD to protect the solar panel,\ninverter and the main panel that connected to the grid. Therefore, the simulation results serve as\nthe basis for controlling the effects of lightning strikes on electrical equipment and power grids\nwhere it provides proper justification on the ââ?¬Ë?where to be installedââ?¬â?¢ and ââ?¬Ë?what is the ratingââ?¬â?¢ of the\nSPD. This judgment and decision will surely reduce the expensive cost of repair and replacement of\nelectrical equipment damages due to the lightning....
A novel all-solid-state, hybrid solar cell based on organic-inorganic metal halide perovskite (CH3NH3PbX3)materials has attracted\ngreat attention fromthe researchers all over the world and is considered to be one of the top 10 scientific breakthroughs in 2013. The\nperovskite materials can be used not only as light-absorbing layer, but also as an electron/hole transport layer due to the advantages\nof its high extinction coefficient, high charge mobility, long carrier lifetime, and long carrier diffusion distance.The photoelectric\npower conversion efficiency of the perovskite solar cells has increased from 3.8% in 2009 to 22.1% in 2016, making perovskite solar\ncells the best potential candidate for the new generation of solar cells to replace traditional silicon solar cells in the future. In this\npaper, we introduce the development and mechanism of perovskite solar cells, describe the specific function of each layer, and\nfocus on the improvement in the function of such layers and its influence on the cell performance. Next, the synthesis methods of\nthe perovskite light-absorbing layer and the performance characteristics are discussed. Finally, the challenges and prospects for the\ndevelopment of perovskite solar cells are also briefly presented....
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