Study Of A Solar-assisted Combined Cooling,Heating And Power System

Energy shortages,environmental pollution and climate changes have become a big challenge in human society.In recent years,distributed cogeneration systems have become more and more concerned by academics and industry as an alternative to solving energy-related problems.At the same time,traditional distributed cogeneration systems relying on natural gas and coal hybrid with renewable energy such as solar energy has gradually become a hot research topic.Since the performance of the solar-assisted combined cooling,heating and power(SCCHP)system mainly depend on the system structure,operation strategy and facility capacity,this paper conducts research on these three aspects.In this paper,the photovoltaic system,solar thermal system and solid oxide fuel cell(SOFC)generation unit are integrated into a SCCHP system,and a static system model based on energy balance is established.In addition,a new operation strategy called hybrid following(HF)operation strategy,integrated with electrical equivalent load following and following thermal load strategy,is proposed and applied in this SCCHP system to evaluate the integrated performances.An integrated evaluation criteria based on economy,energy efficiency and environmental protection was established.Given the proposed operation strategy,the capacity of the key equipment is optimized based on a particle swarm optimization(PSO)algorithm.A case study of an apartment building in Guangzhou is conducted to verify the feasibility of the research method.Through the analysis of the example,the building environment simulation software is used to simulate and predict the electric,thermal and cool load throughout the year.According to the proposed operation strategy,the capacity of the key equipment of the distributed cogeneration system is optimized by the PSO algorithm.The results show that the optimized SOFC generation unit capacity is 39 kW,the number of the PV system is 153,the ratio of electric cooling to cool load is 0.7,the capacity of thermal storage tank is 2600 kWh and the integrated evaluation criteria is 11.06%,respectively.After determining the optimal capacity,the distribution of the hourly energy flow distribution of the SCCHP system under the hybrid following operation strategy are studied and analyzed.Finally,the proposed operation strategy is compared with the traditional following electric/thermal load(FEL/FTL)operation strategies,and the optimal capacity optimization of the key equipment and system performance are analyzed under these three operation strategies(FEL,FTL and HF operation strategies).The results show that due to considering the characteristics of the power fluctuation of the solar subsystem in the SCCHP system,the hybrid following operation strategy can better reflect the load matching relationship between the system and the building.Compared with the other two operation strategies,the hybrid following operation strategy is superior in terms of energy efficiency and emission reduction.