Thermodynamic assessment of an integrated renewable energy multigeneration system including ammonia as hydrogen carrier and phase change material energy storage

Abstract

Sustainable development and effective management of resources has become an integral need of future energy systems. This study considers a unique multi-generation system involving ammonia synthesis using electrolytically produced hydrogen from desalinated water, alongside supply of basic utilities like potable water, heating, cooling, and electricity. The integrated system employs a phase change material based-energy storage unit to provide uninterrupted energy supply to the system. Energy and exergy analysis of the overall and sub-systems based on the first and second law of thermodynamics reveal valuable insights into the performance of such a system. A rigorous analysis of external parameters including environmental temperature, direct normal irradiance on the overall and component energy/exergy efficiencies is performed. The analysis reveals that the utilities demand of a remote area can be met in a more sustainable and environmentally friendly manner using the proposed multi-generation system. An overall system exergy and energy efficiencies of 18.9% and 28.0% respectively are obtained, whereas the sub-systems are also found to have energy efficiencies ranging between 15 and 80%. The highest exergy destruction rates of 25 megawatts and 32 megawatts are observed for the multi-stage flash distillation and the steam Rankine cycle sub-systems respectively. An elementary environmental impact assessment of the same system reveals that the proposed system can help reduce the carbon footprint by almost 60% with no significant compromise on the overall exergy and energy efficiencies.