Thermodynamic Analysis of a Multi-Generation Plant Driven by Pine Sawdust as Primary Fuel

The current study is based on a combined heat and power system with multi-objectives, driven by biomass. The system consists of a combustion chamber (CC), a single effect absorption cooling system (SEACS), an air conditioning unit (AC), a reheat steam Rankine cycle (RSRC), an organic Rankine cycle (ORC) and an electrolyzer. The purpose of this system is to produce hydrogen, electricity, heat, cooling, and air conditioning. All the simulations had been performed by Engineering Equation Solver (EES) software. Pine sawdust is the selected biofuel for the combustion process. The overall utilization factor (εen) and exergetic efficiency (ψex) were calculated to be 2.096 and 24.03% respectively. The performed renewable and environmental impact analysis indicated a sustainability index of 1.316 (SI), and a specific CO2 emission of 353.8 kg/MWh. The parametric study is conducted based on the variation of ambient (sink) temperature, biofuel mass flow rate, and boilers outlet temperatures. The parametric simulation showed that the increase in biofuel mass flow rate has a positive effect on the sustainability of the system. It is noticed that by increasing the biofuel mass flow rate from 0.123 kg/s to 0.22 kg/s, the sustainability index rises from 1.309 to 1.542. However, any increase in boilers outlet temperature and sink temperature, result in a decrease of sustainability index. Keywords: biomass, exergy assessment, multi-objective plant, CO2 emission, irreversibility.