It　is　increasingly　popular　to　use　the　ice　storage　technique　for　shifting　the　electricity　demand　in　the　peak　periods.　In　this　paper,　the　form　of　direct　evaporation　ice-on-coil　storage　technology　is　studied.　A　quasi-steady　state　energy　balance　model　of　the　ice-storage　evaporator　has　been　built　for　simulating　the　freezing　process　on　the　coil.　Good　agreement　is　obtained　between　simulated　results　and　experimental　data.　The　results　show　that　with　the　increasing　ice　layer　thickness,　the　evaporating　temperature　will　decrease.　This　could　result　in　the　reduction　of　the　Coefficient　of　Performance　(COP)　of　system.