A novel analytical method to evaluate the function of thermal energy storage in combined cooling heating and power(CCHP)system in following thermal load mode

摘要

The performance of combined cooling heating and power(CCHP)system is poor when the system working at part load.Thermal energy storage(TES)system is helpful to improve the energy efficiency of system and decrease the capacity of equipment.This paper proposes an analytical method which based upon a new micro-gas turbine(MGT)semi-empirical model,and then the method is used to get a general analysis of part load performance of CCHP system and the function of adding TES in CCHP system in following the thermal load(FTL)mode.The results show:(1)The part load performance and the function of adding TES in CCHP system are influenced by three kinds of factors: no-load fuel consumption ratio and rated efficiency of MGT which are efficiency parameters of equipment,heating load fluctuation factor and ratio of electricity to heat which are building load characteristics parameters,and efficiency of electricity grid which is extra parameter.(2)The exergy loss can be divided into avoidable and unavoidable parts.Adding TES in FTL mode can eliminate avoidable exergy destruction in MGT.(3)TES is more needed when the MGT no-load fuel consumption ratio,MGT rated efficiency and heating load fluctuation factor is bigger,and it's less needed when the ratio of electricity to heat is smaller.(4)Adding TES in CCHP system can get performance improved by 16％and 23％in a restaurant and in a commercial facility in Beijing.