Parametric Investigations and Multi-Objective Optimization of a Reheat Brayton–Regenerative Kalina–Vapor Absorption Refrigeration System: An Energy, Exergy, and Ecology Perspective

Abstract

Abstract. An innovative reheat Brayton–Regenerative Kalina–Vapor absorption refrigeration integrated system was investigated from energy, exergy, and environmental perspectives. The system model, developed in matlab with temperature-dependent thermophysical properties and considering combustion dissociation, was subjected to parametric analysis and multi-objective optimization. The influence of Brayton cycle pressure ratio (rp), Brayton turbine inlet temperature (BTIT), and Kalina turbine inlet temperature (KTIT) on power output, energy utilization factor (EUF), power density (PD), exergy efficiency, dissociation effects, and specific carbon emission rates (SCERs) was assessed. The results show that increasing rp from 3 to 46 at BTIT 1100 °C and KTIT 340 °C enhances EUF from 19.8% to 49.98%, exergy efficiency from 14% to 42.41%, and PD from 64.9 to 1838.4 kW-s/m3. Higher rp suppresses dissociation, as reflected by an increase in the CO2/CO ratio from 0.78 to 2.27. Increasing BTIT enhances efficiency and PD, but promotes dissociation. Compared to the Brayton cycle, the integrated system shows a substantial reduction in SCER from 2.04 to 0.65 kg/kWh at an rp of 3 and BTIT of 1100 °C. Finally, two multi-objective optimization problems were formulated and solved using genetic algorithm. The Pareto frontiers were evaluated using three decision-making approaches to identify the optimal solution. The study concludes that optimized combinations of pressure ratio and BTIT not only maximize energy utilization but also suppress dissociation, establishing the system as a unique pathway for efficient and eco-friendly power–cooling cogeneration.