Thermodynamic analysis of a novel tri-generation system integrated with a solar energy storage and solid oxide fuel cell – Gas turbine

Abstract

The conventional cooling, heating and power tri-generation system still has problems such as high greenhouse gas emissions and high fossil fuel consumption. A new integrated energy system is proposed which includes solar-methanol hydrogen production, energy storage device, solid oxide fuel cell and dual-effect absorption chiller/heat pump with less carbon dioxide emissions, higher energy conversion efficiency and less fossil fuel consumption. The solar energy storage device drives the methanol reformation reaction and the Li-Br chiller/heat pump in parallel, decoupling the power and cooling/heating of the system to simultaneously satisfy the user demands and increases system flexibility. The proposed system is modeled and simulated in Aspen Plus and Fortran. The system thermodynamic performance is analyzed at the design conditions and the results shows the new system obviously enhances the energy conversion efficiency compared with the reference system. The effects of the methanol flow rate on the system output parameters and the thermodynamic performances of the system in different seasons when meeting the cooling, heating and power needs of the district users are studied. The results shows that the maximum system energy efficiency is 92.98% when the system operates in summer, and the system power generation efficiency is 48.03%; in winter, the maximum total system energy efficiency reaches 146.30%, and the system power generation efficiency is 53.26%; in the transition season, the system only needs to provide users with power load and domestic hot water, and the exhaust gas provides the methanol reaction heat. The system power generation efficiency increases to 65.38% and the energy efficiency is 87%.