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This paper describes the control of temperature rise in photovoltaic panels by using wickless heat pipe cooling technique. These heat pipes take the help of gravity for circulation of their working fluid without using a wick structure. For current thermal management study, two solar panels of same dimensions and two identical gravity assisted wickless heat pipes are designed and fabricated. One of the panels is cooled by using these two heat pipes. Other panel, without heat pipes is used for performance comparison purpose and has been designated as the reference module. In order to have the same operating conditions, these panels have been installed together. Experimental parameters such as voltage, current from both panels, module temperatures along with solar irradiance and ambient temperature are recorded with the help of a data logger. For this study, minute wise data of various parameters have been recorded for the test period of 9 AM to 5 PM, since solar radiation intensity is high during this time period. Actual data tabulation for the analysis has been done at 15 minute intervals. The comparative analysis for each panel has been carried out for various dates and has been presented in this paper. A significant drop in temperature of around10%, corresponding to a temperature reduction of5.96°C, has been estimated in the operating temperature of photovoltaic module equipped with wickless heat pipes. Further, due to the thermal management, in this study, the optimum enhancement in photoelectric conversion efficiency is found to be 7.69%, with 15.4% of panel with cooling and 14.3% of panel without cooling. Similarly optimum improvement of 4.03% in power output has been recorded with 27.09 W from panel with cooling and 26.04 W from the panel with no cooling. The outcomes of this experimental study are highly encouraging in the field of photovoltaics. [ABSTRACT FROM AUTHOR]

The aim of the study was to improve the efficiency of the double roller cotton gin in terms of ginning output and energy consumption. Therefore a spike cylinder–type gin feeder with the concept of single locking of cotton bolls was developed and optimized. The speed of the spike cylinder of the single locking feeder and cotton moisture were optimized using response surface methodology for long and medium staple cotton. Ginning output of the double roller gin was maximized and the specific energy requirement for ginning was minimized during optimization. Quadratic models were fitted for prediction of ginning output and specific energy. Optimum cotton moisture of 7.38 and 7.15% and optimum spike cylinder speed of 307 and 297 rpm with desirability of 0.9185 and 0.8923 were arrived at using multiple regression analysis for long and medium staple cotton, respectively. Use of the single locking cotton feeder for long and medium staple cotton resulted in a 22 and 25% increase in ginning output, respectively, and a 12 and 13.5% reduction in specific energy requirement, respectively, compared to the conventional system, the auto-feeder. The single locking feeder showed significant improvement in the color grade of cotton. Other high volume instrument and advanced fiber information system fiber quality parameters remained unaffected. [ABSTRACT FROM AUTHOR]