Thermodynamic and economic analysis of a new CCHP system with active solar energy storage and decoupling of power and cooling outputs

Abstract

The combined cooling, heating and power system effectively improves the energy conversion efficiency and reduces the fossil fuel consumption, can also satisfy multiple energy needs. A new multi-generation system including solar energy storage, thermochemical hydrogen production, solid oxide fuel cell, organic Rankine cycle, and double effect absorption refrigeration/heat pump is proposed, which achieves the decoupling of the cooling/heating output and power output by active energy storage method and effectively enhances the system flexibility to match the user loads. Two improved operation strategies of the new system are proposed to meet the user loads, with fuel saving rate of 19.31 %. The levelized cost of product, static payback period, dynamic payback period of the system under grid-assisted strategy are 0.0443$/kWh, 5.13years, 5.72years, respectively. While under the strategy of extra methanol to electricity for cooling, they are 0.0617$/kWh, 8.17years, 10.09years, respectively. On a typical day in summer, the CO2 emission rates are 144.07 g/kWh under grid-assisted strategy and 81.74 g/kWh under the strategy of extra methanol to electricity for cooling. On the typical day during the transition season and winter, the CO2 emission rates are 15.76 g/kWh and 53.52 g/kWh, respectively. The results of both operation strategies indicate the new system is economically viable and environmentally friendly.