Energy, exergy, economic and emission saving analysis and multiobjective optimization of a new multi-generation system based on a solar tower with triple combined power cycle

In the present work, an original solar tower based multi-generation system with triple combined power cycle is proposed and investigated in detail. The novel system deploys a solar tower-based Brayton cycle, a single-stage regenerative organic Rankine cycle and a Goswami cycle. A multi-effect desalination, an electrolyzer and a LiBr absorption cooling system are coupled to the triple combined power cycle for the purpose of power, heating, fresh water, green hydrogen, refrigeration, space cooling and hot water production. Thermodynamic, economic and emission saving viewpoints are examined together with parametric investigation. Effect of variation of power size of the electrolyzer on the overall system performance and effect of change in solar irradiation are also analyzed. Multiobjective optimization is performed considering thermodynamic and economic objectives simultaneously. At the optimum conditions, proposed system has 51.99% and 37.99% energy and exergy efficiency values, respectively, and achieves 513.8 kg CO₂/h emission savings and 0.0352 $/kWh unit product profit. Total revenue rate and total cost rate are calculated as 168.2 $/h and 92.3 $/h, respectively. Discounted payback period calculation shows that the system compensates itself economically in 4.79 years.