Thermodynamic and economic analysis of a hybrid ocean thermal energy conversion/photovoltaic system with hydrogen-based energy storage system

The purpose of this study is to define and assess a new, renewable and sustainable energy supply system for islands and remote area where ocean thermal energy conversion (OTEC)/photovoltaic with hydrogen storage system is proposed. Components of this system are a turbine, generator, evaporator, condenser, pumps, photovoltaic panels, electrolyzer, hydrogen tanks, fuel cell and converter. To evaluate the proposed hybrid system, energy, exergy and economic analysis are employed. For OTEC, an optimization algorithm is applied to find the optimum working fluid (R134A, R407C, R410A, R717, R404A, and R423A), evaporation and condensation temperatures, and cold and warm seawater temperature differences between the inlet and outlet of evaporator/condenser. The results demonstrate that the maximum specific power of OTEC was achieved to be 03622 kW/m(2) for R717 and 0.3294 kW/m(2) for R423A working fluids. The overall energy efficiency for the hybrid renewable energy system was obtained 3.318%. The maximum energy loss was occurred by the turbine. The exergy efficiency of the hybrid system was obtained 18.35% and the payback period of the proposed system was obtained around 8 years. The unit electricity cost for the system was achieved as 0.168 $/kWh which is valuable compared to 0.28 $/kWh of the previous system. (C) 2019 Published by Elsevier Ltd.