Economic and environmental assessment and bi-objective optimization of a novel biomass-powered co-generation system: Impact of design parameters

Abstract

Organic flash cycle facilitates high heat recovery and seamless integration with refrigeration cycle. Moreover, the use of a two-phase ejector in the organic flash cycle enables operation at temperatures below zero and enhances cooling/power production. A parametric study is conducted to scrutinize the influence of key design variables gas turbine inlet temperature (T3), flash tank inlet temperature (T14), and air compressor pressure ratio (P2/P1) on plant outputs. P2/P1 is a crucial design factor affecting overall performance, optimizing efficiencies and reducing levelized cost of product at a ratio of 5. Additionally, T3 has positive effects on several performance indices, but higher values lead to decreased system-generated cooling from 910.2 kW to 774.1 kW. Meanwhile, T14 has mixed effects, improving system-generated electricity, sustainability index, levelized cost of product, CO2 emission rate, and exergy efficiency, but negatively impacting system-generated cooling, energy efficiency, and total investment cost rate. The optimization process has a positive impact on system-generated electricity, emitted CO2 rate, sustainability index, exergo-environmental index, energy efficiency, and exergy efficiency, leading to their respective values reaching 5945 kW, 0.9648 kg/kWh, 1.511, 0.6158, 10889 kW, 42.37%, and 33.82. Meanwhile, system-generated cooling, total investment cost rate, and levelized cost of product show performance degradation.