Dynamic thermo-ecological cost assessment and performance analyses of a multi generation system

Abstract

The main objectives of this study are to perform a dynamic thermo-ecological cost (TEC) assessment and performance analyses of a multi generation system using the TRNSYS 18 software package for comparison purposes. The system has five outputs consisting of electricity, clean water, heating, hydrogen, and cooling. Multigeneration is made of an internal combustion engine fueled by natural gas, a heat pump, a reverse osmosis desalination plant and a magnesium-chlorine (Mg–Cl) thermochemical (TC) water splitting cycle. This cycle, which appears to be a promising TC hydrogen production method, is integrated to the multi generation system for producing hydrogen for waste heat recovery. Environmental effect of the system is also considered using the TEC method. In this contribution, a new index, namely the TEC of the irreversibility, is presented and applied. Variation of emissions, electricity, exergy destruction and energy loss values for the considered system and Mg–Cl TC water splitting cycle as well as TECs of the electricity, heat and the hydrogen are calculated through some parametric studies undertaken and presented in figures. It is determined that the multigeneration system has an energy efficiency value of 0.43 and a corresponding exergy efficiency of 0.38. As a result, TECEL, TECHEAT and TECH2values of the considered system are obtained to be 2.98, 0.72 and 2.90, respectively. It may be concluded that the TEC is an effective method to assess the environmental performance of various energy systems and compare them with each other.