The compound parabolic collector (CPC) with pulsating heat pipe (PHP) is developed for enhance the heat transfer rate, thermal efficiency and heat losses, and so forth. and working fluid plays a major role in this process. The thermal resistance, temperature, and thermal efficiency have been experimented with under different conditions, and heating periods were analyzed. In this, cobalt oxide (Co3O4) and graphene oxide (GO) added distilled water (DW) is used as the working fluid in the filing ratio of 50%. Bald eagle search optimization (BES) algorithm is used for optimizing the experimented values, and the better‐optimized values are used for hybrid BES based deep belief network (DBN) prediction. The maximum temperature obtained for experiment and optimization is 65 and 65.16161°C. 59% of thermal efficiency was obtained as maximum for experimentation, and 59.1542% of thermal efficiency was obtained as maximum for optimization. The maximum thermal resistance obtained for experimentation and optimization is 0.08 and 0.06938°C/W. In this, optimized outputs performed well than the experimental values. Besides, the hybrid DBN based BES algorithm is performed based on the optimized performances to predict the temperature, thermal efficiency and thermal resistance. Further, predicted outcomes are compared with the non‐hybrid neural networks such as DBN, CNN and ANN. DBN‐BES depicts low error values than the non‐hybrid neural networks. Overall, the proposed hybrid solar collector model and the hybrid nanoparticles added water helps to enhance the thermal characteristics with minimum heat loss.

In this study, the combustion chamber geometry for spray-guided, wall-guided, and air-guided combustion strategies were fabricated. The piston crown shape and the cylinder head in each combustion chamber geometry was machined by fixing the fuel injector and spark plug at proper positions to obtain swirl, turbulence, and squish effects for better mixing of fuel with air and superior combustion of the mixture. Conducted tests on all the three modified gasoline direct injection engines with optimized exhaust gas recirculation and electronic control towards fuel injection timing, the fuel injection pressure, and the ignition timing for better the performance and emissions control. It is clear from the results that NOx emissions from all three combustion modes were reduced by 4.9% upto 50% of loads and it increase for higher loads due to increase of in-cylinder pressure. The fuel consumption and emissions showed better at 150 bar Fuel Injection Pressure for wall-guided combustion chamber geometry. Reduced HC emissions by 3.7% and 4.7%, reduced CO emissions by 2% and 3.3%, reduced Soot emissions by 6.12% and 10.6%. Reduces specific fuel consumption by about 10.3% and 13.3% in wall-guided combustion strategy compare with spray-guided and air-guided combustion modes respectively.

In the present work, developed the combustion chamber profiles for spray, wall, and air guided mode GDI engines. Modified the piston top surface for each combustion chamber geometry of GDI engine from hemispherical bowl to trapezoidal bowl and pent roof shape which include a scoop type bowl on one side (towards injector position) to impart better squish, swirl, tumble and turbulence effects required to improve the mixture formation. Also, modified the cylinder head to each combustion chamber with different locations of spark plug and fuel injector. Optimized the fuel split injections with durations, ignition timing and percentage of exhaust gas recirculation towards emissions reduction, especially soot and oxides of nitrogen. Emission tests were conducted on base diesel engine and all three modified combustion chamber geometry GDI engine. It is clear from the results that oxides of nitrogen emission in wall guided mode was reduced up to 5% till 75% of the loads when compare with both spray-guided and air-guided combustion modes, and later it is increased. Overall, wall guided combustion chamber geometry GDI engine shows better results at 150 bar FIP, when compare with base Diesel engine; oxides of nitrogen emissions were reduced from 377 ppm to 77 ppm and soot emissions were reduced from 29.3 g/km to 4.5 g/km at high torque.

Open drying is practiced for drying Capsicum frutescens in the cottage industries of India. In order to improve drying, an experimental set-up of solar rack dryer is constructed and studied different heat transfer augmentation techniques. A passive heating coil extended from the header of a water-in-glass evacuated tube coupled with parabolic trough is used to augment the heat in the collector section of the dryer. The drying rate in rack dryer is found to be 62% higher than that of open air drying of green chillies. Moreover, the drying rate in augmented rack dryer is found to be 7% higher than that of rack dryer. In addition to this, an effective design for the dryer cabinet with respect to air circulation is arrived through computational fluid dynamics analysis. Through this new design, the drying rate is improved further by 3%. Based on energy analysis, the specific energy consumption during the drying of this particular product using the augmented dryer is found to be 1.27 kWh/kg. The exergy efficiency of the drying chamber is found to be in the range of 4%-45% with an average of 16% for Capsicum frutescens.

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