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In recent years, research on enhancing the efficiency of clean and renewable energy systems has increased. This study examines how a micro-scale solar Brayton cycle application performs about the conical cavity thermal receiver shape. Additionally, it establishes the ideal receiver configuration under consideration. The new work explicitly addresses the optimization of a microscale conical model, building on earlier studies by the research team that stressed the significance of reducing total heat losses. The receiver model was created using Design Modeler and treated using CFD analysis in ANSYS 2021R2 Workbench software to limit the convective mode of heat loss. Surface optimization techniques were then used, and the results were examined. To confirm the achieved results, the direct optimization method was also utilized, and it gave the same results. The internal height and the two edges on the bottom width of the receiver were found to have the greatest influence on the value of the heat transfer coefficient. Thermally, the dimensions of the optimized conical shape were found to be 384, 198, 114, 48 and 57 mm for the internal height, total width, top width, left edge and right edge respectively. The results of this investigation showed that by reducing the heat transfer coefficient by up to 90%, the tested shape's thermal performance was significantly improved. It consequently led to an increase in overall system efficiency of around 1.3%–1.95%.

In this study, a branched GAX absorption cycle operating with NH3-H2O pair has been investigated to assess its performance under steady state conditions. The cycle modeling is implemented using Engineering Equation Solver (EES) software. Analysis includes equations of mass, species and energy conservation. The analysis is used to simulate a GAX absorption chiller utilization for air conditioning applications with a nominal capacity of 95 TR. This chiller uses solar collectors as heat source. The operating parameters are selected at different values of the heat source temperature (140 - 185°C), condenser exit temperature (30 to 48°C), evaporator exit temperature (2 to 11°C) ; split ratio (0 to 0.18); the difference in ammonia concentration(0.25-036), mass flow rate in solution pump mr=1 kg/s; heat exchanger effectiveness   0.8. The results showed that the average COP is sensitive to operating conditions where the average COP and cooling capacity of the branched GAX absorption chiller increase with increasing generator and evaporator temperature whereas they decrease with increasing condenser temperature. Simulation results also show that the split ratio and ammonia concentration difference have a significant impact on the performance of absorption chiller.