a modified biogas-driven combined cooling and power system based on open and close brayton cycles

A novel method of a biogas-driven cogeneration system for electricity and cooling with recovering liquefied natural gas heat sink is introduced in this study. the proposed system consists of an open loop brayton cycle or gas turbine cycle fed by biogas, a close loop brayton cycle, a liquefied natural gas open power generation cycle, and a dual-stage combined cooling and power unit composed of an organic rankine cycle integrated with an ejector refrigeration cycle. the superiority of the system over previous models is demonstrated from the thermodynamic and economic points of view. in addition, a multi-criteria optimization of the proposed set-up is conducted regarding crucial decision variables, energy and exergy metrics, and unit overall product cost as objective functions. it is deduced that gas turbine 1 inlet temperature is the most influential decision variable affecting the objective functions. from the optimization, it is discovered that the developed unit can generate cooling and net electricity of 424.1 kw and 1,864 kw, correspondingly, resulting in energetic efficiency of 80.4%, exergetic efficiency of 41.24%, and unit cost of 10.07 $/gj. the performance of the biogas-fueled combined system can be improved by 71.17% in the form of energy efficiency at the optimum scenario. among all elements available in the developed cogeneration system, the combustion chamber has the highest contribution to the overall exergy destruction rate, followed by the condenser.