Pumped thermal electricity storage(PTES) technology can make use of different types of thermodynamic cycles and thermal storages. To study the loss-generating mechanism and the effects of various losses on cycle efficiency of the PTES

thermodynamic analysis is presented based on the conventional cycle calculations coupled with parameter sensitivity analysis of influence factors. The thermodynamic models of the PTES charge/discharge process are established

and the thermodynamic cycle parameter sensitivity is analyzed by variable control

focusing on various losses and their effects on cycle efficiency of the PTES. The sensitivity coefficients

namely the affecting degree of various parameters on the cycle efficiency

are obtained. The results show that

through optimizing the key design parameters that affecting the cycle efficiency the most

such as enhancing the compression and expansion efficiencies

and reducing the mechanical losses and heat transfer temperature difference

can improve the PTES system's performance. The results can provide theoretical reference for PTES system optimum design.