A　more　realistic　thermodynamic　model　of　the　pumped　thermal　electricity　storage　(PTES)　system　consisting　of　a　Brayton　cycle　and　a　reverse　Brayton　cycle　is　proposed,　where　the　internal　and　external　irreversible　losses　are　took　into　account　and　several　important　controlling　parameters,　e.g.,　the　pressure　ratio　and　heat　flows　of　the　two　isobaric　processes　in　the　Brayton　cycle,　are　introduced.　Analytic　expressions　for　the　round　trip　efficiency　and　power　output　of　the　PTES　system　are　derived.　The　general　performance　characteristics　of　the　PTES　system　are　revealed.　The　optimal　relationship　between　the　round　trip　efficiency　and　the　power　output　is　obtained.　The　influences　of　some　important　controlling　parameters　on　the　performance　characteristics　of　the　PTES　system　are　discussed　and　the　optimally　operating　regions　of　these　parameters　are　determined.　©　2016　Elsevier　Ltd