Exergoeconomic modeling and parametric assessment of a geothermal multi-generation system using LNG cold energy

The current work deals with the development and simulation of a new geothermal driven poly-generation system exergetically and economically. The proposedsystem involves a cascade organic Rankine cycle (ORC) and proton exchange membrane (PEM) electrolyzer to produce power, the vaporized liquefied naturalgas (LNG), the cooling effect and hydrogen. From the simulation results, the energy and exergy efficiencies are calculated within 82.6% and 38.8%,respectively. To assess the performance of the proposed system four major design parameters, namely LNG pressure (PLNG), LNG mass flow rate ( LNG m ), upper cycleturbine inlet pressure (P4) and upper cycle mass flow rate ( upper m ) are considered.Sensitivity analysis implies that both LNG m and PLNG increase the thermal efficiency and total product cost rate ( P C ) of the overall system by about 23.26% and48.83%, respectively while they have a negative effect on the exergy efficiency within 5.8%. Moreover, P4 and upper m simultaneously reduce the thermal efficiency and P C by 3.3% and 15.05%, respectively.

Keywords:

Multi-generation , H2 production , LNG vaporization , geothermal