Coupling Characteristics Analysis Of Solar Thermal And Novel CCHP Complementary Power Generation System

With the improvement of social development and modernization,people pay more attention to efficient and clean energy systems.The drawbacks of the centralized energy system represented by thermal power generation have been highlighted,exposing problems such as environmental pollution,slow demand response and low energy efficiency.Therefore,building a clean,low-carbon,safe and efficient energy system is the mainstream of energy development strategy.Combined cooling heating and power(CCHP)system can meet the diversified energy needs of customers while making full use of local renewable resources.It is significant to promote the energy structure transformation by realizing multi-energy synergistic supply and energy cascade utilization.In this context,this paper taking the CCHP integrated solar thermal utilization system as the research object,and investigates the effect of operating parameters and operating strategies on system performance.Firstly,this paper proposes a CCHP system coupling solar thermal(ST)system with organic flash cycle(OFC),and thermodynamic modeling of the system components.In order to apply the CCHP-ST-OFC system to the building,the cooling,heating,and electrical loads of the users are calculated using the De ST software,and the loads of users at the winter and summer solstices are studied.Secondly,the thermodynamic analysis of the CCHP-ST-OFC system is carried out on the basis of energy and exergy analysis.Taking system energy supply,primary energy ratio and exergy efficiency as evaluation indexes,the effects of different configurations and operating parameters on the system performance are investigated.The results show that the CCHP-ST-OFC system is better than the CCHP system using organic Rankine cycle in terms of energy output and energy efficiency.the power of internal combustion engine and flash temperature have a greater influence on the system performance.The system thermoelectric ratio ranges from 0.43 to 1.04 by adjusting the smoke temperature at the outlet of the waste heat recovery equipment.Finally,two improved follow electric load,the FEL strategy considering negative feedback(NFEL)and the FEL strategy considering operational flexibility(FFEL),are proposed and applied to customer energy supply.In order to obtain the optimal configuration of the CCHP-ST-OFC system under different operation strategies,this paper considers levelized cost,carbon emission and renewable energy ratio as performance parameter indicators,constructs a multi-objective optimization model,and solves the model using genetic algorithm.Moreover,to reduce the multi-objective model solving time,the system structure is simplified using the random forest algorithm in this paper.The results show that the FFEL strategy has the lowest levelized cost(0.585 (?)/kWh)when the lowest cost is the main optimization objective.It is 6.2% and 3.3% lower than the FEL strategy and the NFEL strategy,respectively.When the lowest carbon emission is the main optimization objective,the NFEL strategy has the lowest emissions(0.121 kg/kWh),which is 6.0% and 3.2% less than the FEL strategy the NFEL strategy,respectively.