A nuclear driven hybrid sCO2 power cycle/ membrane distillation system for water-electricity cogeneration

Abstract

By integrating a membrane distillation (MD) block with a nuclear driven supercritical CO2 (sCO2) power block, a novel water and electricity cogeneration system is proposed, aiming at the water and energy supply for remote islands and coastal households. MD uses the waste heat from the sCO2 power block through an intermediate heat exchanger (IHX), while the exhaust low-pressure sCO2 flow leaving from the low temperature recuperator (LTR) is cooled by the seawater introduced into MD, without influencing the efficiency of power block. Steady state thermodynamic and economic analysis for the subsystems and the hybrid system are carried out by considering the effects of operation conditions and membrane properties. As the optimal performance of each single subsystem does not always correspond to the optimal performance of the cogeneration system, optimization genetic algorithm is employed to obtain the solutions to optimal block performance and optimal cogeneration system performance, respectively. The results predict that the maximum energy efficiency of the power block and the desalination block is 48.18% and 37.10%, respectively. The minimum levelized cost of electricity (LCOE) and levelized cost of water (LCOW) are 0.0527 $/kWh and 0.445 $/m3, respectively. The maximum exergy efficiency of the hybrid system is 67.82%. The nuclear driven sCO2-MD system is proved to be an effective layout to enhance the nuclear energy conversion efficiency and reduce water and electricity generation costs.