Air-phase　change　thermal　storage　devices　are　in　great　demand　in　the　fields　of　crop　drying,　flue　gas　waste　heat　recovery　and　building　heating.　However,　the　current　research　on　air-phase　change　thermal　storage　devices　is　few　and　the　structure　is　mostly　flat.　Based　on　previous　experimental　studies,　this　study　used　numerical　simulation　methods　to　study　the　thermal　performance　of　four　structures　of　multichannel　channel　flat　tube　phase　change　thermal　storage　devices　to　ease　the　problems　of　irrational　heat　transfer　structure　and　low　compact　factor.　The　compact　factor　of　the　device　is　improved　by　changing　the　height　of　the　flat　tube　ribs.　The　effectiveness　and　specific　power　are　used　as　evaluation　indicators.　The　results　show　that　when　the　length　of　the　multichannel　flat　tube　is　perpendicular　to　the　direction　of　gravity　and　the　air　is　injected　from　the　side,　the　performance　of　the　device　is　greatly　exerted.　Compared　with　the　original　research,　the　phase　change　completion　time　is　improved　by　20.59%.　The　results　show　that　0.03　m　is　a　reasonable　flat　tube　rib　height.　In　this　case,　the　compact　factor　is　61.5%.　©　2021,　Science　Press.　All　right　reserved.