Comprehensive evaluation of a new integrated ORC-VCR system with a thermoelectric generator unit combining sustainable energies for hydrogen production

Abstract

Recently, there has been a growing emphasis on the efficient generation of energy from sustainable sources. This study aims to evaluate a new combined Organic Rankine Cycle-Vapor Compression Refrigeration (ORC-VCR) system from energy, exergy, economics, and environmental perspectives. The system has been designed to cogenerate power, heat, cooling, and hydrogen using solar and biomass energy. To enhance efficiency, a Thermoelectric Generator (TEG) unit has been integrated into the system. The power produced by the TEG is used to generate hydrogen in the Proton Exchange Membrane Electrolyser (PEME). To ensure the continuous operation of the solar collector, especially under conditions of unstable and intermittent solar radiation, a thermal storage tank and a biomass-fired boiler utilizing four different types of biomass (wood, paper, municipal solid waste, and sawdust) have been incorporated. The primary objective of this research is to investigate the impact of employing various biomass types on the system's performance. The results indicate that in terms of energy and exergy, municipal solid waste yields the highest system efficiency. However, from an environmental viewpoint, paper incurs lower pollutant emissions. The proposed hybrid system can produce 145.5 kW of cooling, 513.6 kW of heat, 37.93 kW of electricity, and 0.756 kg/h hydrogen with energy and exergy efficiencies of 32.73% and 14.18%, respectively. The estimated total equipment cost is 7.67$/h, with a CO2 emission of 0.0029 kg/s.