Study Of A Methanol Combined Cooling Heating And Power System Based On Full-spectrum Hybrid Solar Energy Device

Solar-assisted conventional gas-fired combined cooling,heating and power systems(CCHP)are based on the principle of "temperature counterpart and energy gradient utilization",which improves the energy utilization of the system to a certain extent by virtue of the clean and renewable nature of solar energy.However,the integration of solar energy with conventional CCHP systems is mainly through components such as solar collectors,photovoltaic panels and photovoltaic/thermal collectors,which only make use of part of the solar spectrum and do not make full use of solar energy.Based on the perspective of full-spectrum solar energy utilization,in this paper,a full-spectrum hybrid solar device(HSED)containing a molecular solar thermal(MOST)storage system and a solar heat collector(SHC)is integrated with a methanol CCHP system,improving the energy utilization of the CCHP system and providing a new form of integration of solar energy and CCHP systems.Firstly,a full-spectrum HSED,a chemical recuperator unit and a CCHP system are integrated based on the principle of "temperature counterpart and energy gradient utilization".Thermodynamic models of the individual components were developed in the EES software and compared with existing literature to verify the accuracy of the models.Secondly,according to the load demand of a hotel in Beijing,the operation strategy of the CCHP system and the capacity of each component was determined was designed.Based on the first and second laws of thermodynamics,the thermodynamic performance of a full-spectrum methanol CCHP system at design working conditions were analyzed,the performance of the proposed full-spectrum methanol CCHP system is compared with that of a conventional methanol direct-fired CCHP system,highlighting the energy and environmental benefits of the system.Additionally,the effect of solar irradiation intensity and internal combustion engine(ICE)load rate on the thermodynamic performance of the CCHP system was studied.The results show that compared with the methanol direct-fired CCHP system,the energy efficiency of the full-spectrum methanol CCHP system under the design working conditions is increased by 11.21% in summer and 17.80% in winter,respectively,and the exergy efficiency of the CCHP system is increased by 3.32% and 3.59%,respectively,saving26.47% of fuel and reducing 77.33% of carbon dioxide emissions.Finally,the area ratio of the SHC to the MOST system of the HSED was used as the decision variable,the energy saving rate,carbon dioxide emissions reduction rate,and unit exergy cost saving rate as an objective function,a multi-objective optimization model of the proposed solar full-spectrum methanol CCHP system was established,the optimum configuration of a full-spectrum HSED was obtained.In the optimal configuration,the exergoeconomic assessment was carried,the effects of area ratio of SHC to MOST system,heat storage rate,supplemental heat rate,methanol prices,solar device cost rate,ICE and HSED operating hours on the exergoeconomic performance of the CCHP system was analyzed.The optimization results show that the comprehensive performance of the full-spectrum methanol CCHP system is optimal when the area ratio of SHC to MOST system is 0.5,at which time the CCHP system saves 24.71% of fuel and reduces 70.82% of carbon dioxide,but increases 28.60% of the unit exergy cost.