Integrated renewable-based multi-generation system with environmental and economic optimization

Abstract

Utilizing renewable reservoirs as a primary source of energy in power systems significantly mitigates environmental concerns. This approach, coupled with the integration of various subsystems, yields multiple products, thereby enhancing economic benefits. This paper introduces an innovative multi-generation system based on a gasifier-fed solid oxide fuel cell. In this system, waste heat recovery is achieved through a bespoke transcritical CO2 cycle, combined with a Kalina cycle and an organic Rankine cycle subsystem. Additionally, a proton membrane electrolyzer is employed to supply a reactor for ammonia production. A comprehensive analysis of this configuration is performed, employing thermodynamic, economic, and environmental assessment methodologies. Moreover, two multi-objective optimization strategies are implemented to determine the system's optimal operating conditions. The results demonstrate that the proposed system generates a net power output of 293.1 kW, provides cooling of 40.8 kW, produces hydrogen at a rate of 2.689 kg/h, and ammonia at a rate of 15.14 kg/h. The environmental and economic impacts of these products are quantified as an exergoenvironmental impact rate of 111.89 Pt/h and a cost rate of 11.77 $/h, resulting in an exergy efficiency of 27.59%. Furthermore, the system's financial feasibility is evident from its payback period of approximately 3.42 years and a net present value of 1.64 M$. The study also identifies that variations in the fuel cell's current density significantly influence the system's exergy performance and environmental footprint.