Abstract
This dissertation explores an optimised approach for waste heat recovery and thermal management in proton exchange membrane (PEM) electrolysers used in green hydrogen production. The research is motivated by the need to improve energy efficiency and system performance in hot climate regions, where thermal loads are high and energy demands for cooling are significant. A case study is conducted at a Gulf-region airport to evaluate the practical implementation of the proposed system.
The integrated approach includes the use of thermal storage tanks, optimised heat exchangers, and targeted control strategies to recover and repurpose excess heat for domestic hot water production and the preheating of make-up water. The methodology involves developing a dynamic thermal model of the integrated system, simulating heat flows, storage dynamics, and cooling loads under representative airport conditions. The model integrates heat recovery, thermal storage, and cooling systems, optimised to minimise energy use and CO₂ emissions while maintaining stable electrolyser operation. A smart control strategy adjusts chiller operation and pump speeds in real time to minimise energy use, shift peak loads to off-peak periods, and maintain optimal operating temperatures for the electrolysers. Novel chiller scheduling and pump operation strategies further reduce overall energy consumption and improve system performance.
Simulations were carried out to assess the system’s technical and environmental performance. The results indicate considerable energy savings, improved chiller coefficient of performance (COP), and a reduction in carbon emissions.
Analytical results obtained from simulations show that the proposed optimisation reduces air-cooled chiller energy consumption by 28%, circulation pump energy by up to 56%, total power cost by 33%, and CO₂ emissions by 33% (~94 tonnes/year). These promising findings highlight not only the technical viability but also the economic feasibility of implementing waste heat recovery systems, ultimately offering a sustainable and practical solution for renewable energy applications specifically tailored for hot climate regions.
Overall, the study provides a practical framework for optimising waste heat recovery from green hydrogen systems and controlling the PEM electrolyser temperature within recommended limits, while minimising energy consumption in the cooling system. This framework supports the broader adoption of integrated energy solutions in climates where energy efficiency is both critical and challenging.