Electric　energy　storage　techniques　are　imperative　when　integrating　intermittent　renewables　to　power　system　to　conquer　the　mismatch　between　power　generation　and　consumption.　In　order　to　expand　the　energy/power　capacity　of　compressed　air　energy　storage　system　(CAES)　flexibly　in　a　fixed　cavern　size　condition,　a　combined　heat　and　compressed　air　energy　storage　system　(CH-CAES)　with　packed　bed　unit　and　electrical　heater　based　on　adiabatic　concept　is　developed.　In　such　a　system,　electricity　is　stored　in　the　form　of　both　thermal　and　pressure　energies.　In　order　to　predict　the　system　transient　behaviors,　the　turbomachinery＇s　off-design　performance　and　1D　two-phase　transient　model　of　packed　bed　have　been　adopted.　Firstly,　the　thermodynamic　analysis　in　first　cycle　has　been　conducted.　Results　show　that　a　system　roundtrip　efficiency　of　58.86%　can　be　achieved　when　the　packed　bed　unit　efficiency　is　92.53%.　Then,　the　variations　of　both　system　and　component　performances　during　multiple　successive　cycles　are　implemented.　Both　roundtrip　efficiency　and　thermal　energy　storage　efficiency　increase　with　raised　cycles.　Links　between　components　are　discussed.　The　temperature　distribution　in　packed　bed　varies　in　each　cycle,　leading　to　an　improvement　in　high-pressure　turbine　inlet　temperature　and　thus　the　change　of　turbine　performance.　Finally,　the　influence　of　power　distribution　ratio,　electrical　heating　temperature　and　partial　charging/discharging　on　system　performance　is　discussed.　System　roundtrip　efficiency　increases　with　power　distribution　ratio　but　decreases　with　electrical　heating　temperature.　©　2019　Elsevier　Ltd