Simulation Research On The Novel Pumped Thermal Electricity Storage Technology

With the development of varieties of energy structures such as renewable energy and distributed energy,electric energy storage has become a key technology in order to overcome the intermittent and instability of renewable energy as well as to enhance the efficiency and safety of regional energy system.Pumped Thermal Electricity Storage is a novel large-scale electric energy storage technology based on power cycle and thermal energy storage technology.This technology has arisen extensive attention due to varieties of advantages such as no limitation to geographic condition,low cost,high energy storage density and high system efficiency.As a consequence,the research of Pumped Thermal Electricity Storage is necessitate for the development of energy storage technology.The thesis expatiates the principle and characteristic of Pumped Thermal Electricity Storage,which is described in regard to cycle types and working medium.The principle,characteristic and development of Pumped Thermal Electricity Storage is illustrated in detail in terms of power cycle and working medium.Key technology and development tendency of Pumped Thermal Electricity Storage is also analyzed.Pumped Thermal Electricity Storage,which is based on forward/reverse Brayton cycle,is modeled and discussed.This thesis also launches comprehensive analysis of influence on the performance of Pumped Thermal Electricity Storage system by varieties of parameters such as type of cycle fluids,pressure ratio of charging/discharging process as well as isentropic efficiency and mechanical efficiency of contraction/expansion process.Physical and numerical model of heat/cold tank in electricity storage process is achieved to analyse the influence of aspect ratio of tank and thickness of insulation on heat charging/discharging and cold charging/discharging.To achieve the objectives mentioned above,research methods of this project includes;Performance analysis:Model and numerical simulation of Pumped Thermal Electricity Storage system based on published literatures is carried out and then validated.By applying the validated model,novel Pumped Thermal Electricity Storage system is simulated and the analysis platform of system parameter is achieved.Analysis of heat/cold charging and heat/cold dischargingin heat and cold reservoir:Numerical simulation of heat/cold reservoir from published literatures is presented based on CFD commercial software Fluent as well as user-defined functions(UDF)and then validated.By applying the validated model,numerical simulation for heat/cold reservoir in the novel Pumped Heat Electricity Storage system is developed.Finally,the performance of heat/cold reservoir is obtained.Analysis of system economy:Capitalized cost of system construction is obtained by performing the economy analysis of Pumped Thermal Electricity Storage with load of 1MW.The economy of Pumped Thermal Electricity Storage is demostrated compared with other electric energy storage technologys.In view of advantages such as no limitation to geographic condition,high energy storage density and system efficiency,Pumped Thermal Electricity Storage is a competitive large-scale electric energy storage technology compared to Pumped Storage and Compressed Air Energy Storage.