Electricity and hydrogen cogeneration: A case study simulation via the Aspen plus tool

Abstract

The focus of the current study is on a cogeneration unit designed to produce both electricity and hydrogen, which is made up of a parabolic trough collectors’ field associated with a storage tank, a recuperative organic Rankine cycle module, and a proton exchange membrane water electrolyzer. The latter system operates using electricity generated by the organic Rankine cycle to produce hydrogen, which can subsequently be used as either a fuel or a storage medium for seasonal storage. The study begins with a thermodynamic investigation under both steady-state and dynamic conditions. The solar field is simulated using the Engineering Equation Solver, while the organic Rankine cycle and the electrolyzer are modeled in Aspen Plus. The analysis extends to economic and environmental evaluations, along with an optimization procedure based on techno-economic criteria. Regarding the optimum design case, the annual net electricity yield is determined at 333.8 MWh, the yearly hydrogen production amount is equal to 6236.6 kg, while the yearly energy efficiency is calculated at 14.9% and the yearly exergy efficiency at 15.9%. Finally, the economic investigation indicates the net present value is about 645,555 €, while the system contributes to saving 198.1 tnCO2-eq during the yearly operation.