THERMODYNAMIC ASSESSMENT AND OPTIMIZATION OF A NOVEL TRIGENERATION ENERGY SYSTEM BASED ON SOLAR ENERGY AND MSW GASIFICATION USING ENERGY AND EXERGY CONCEPT

Abstract

The current study aimed at delving into the thermodynamic study of a trigeneration cycle based on biomass fuel, combined with an Organic Rankine Cycle (ORC) and an absorption chiller. Biomass fuel is purely produced from Municipal Solid Waste (MSW). Energy and exergy analyses were carried out using the solar collector employing optimized characteristics to provide the required thermal energy at the ideal condition to utilizing in the high-temperature gasification process having hot steam. For supplying electricity, heating and cooling power, a Rankine cycle including a turbine, a heater, and a single effect absorption chiller was considered. To solar energy exploitation, a parabolic trough solar collector and hot steam gasifier were utilized. ORC can efficiently recover low-grade waste heat due to its excellent thermodynamic performance. Based on the examinations, the effects of critical thermodynamic parameters on the exergy efficiency and optimization of the trigeneration cycle and ORC with R134a, as working fluid, was conducted to achieve the system optimization design from thermodynamic aspect through Genetic Algorithm (GA). In this study, exergy destruction and its percentage in the power generation process were calculated as well. Results indicated that the studied system has the potential to generate 11.2 kW electricity, 17.4 kW heating power, 15.3 kW cooling power with the energy and exergy efficiencies of 64.3 % and 52%. It was also revealed that the output power of this system is fixed on the constant amount of 11.2 KW, which is obtained from the microturbine and ORC turbine. Additionally, it was demonstrated that the most exergy destructions are for gasifier, compressor, and combustor respectively, containing 47 %, 26.3 % and 14 % of the destructions. Finally, the optimized performance of the system was determined using GA and exergy efficiency as an objective function. The optimized trigeneration energy system could yield the exergy efficiency of 4.4%.