This　study　seeks　to　optimize　the　performance　of　an　integrated　collector–storage　solar　air　heater　(ICSSAH)　based　on　lap　joint-type　(LJT)　flat　micro-heat　pipe　arrays　(FMHPAs)　and　latent　thermal　storage　through　numerical　simulation.　A　novel　dynamic　heat　transfer　model　is　developed　by　incorporating　the　heat　transfer　correlation　describing　the　thermal　characteristics　of　phase　change　material　(PCM)　in　narrow　and　elongated　confined　spaces　within　plate　fins　and　validated　using　experimental　data　to　address　the　issue　of　deviation　caused　by　the　fixed　thermal　resistance　of　the　PCM　in　conventional　numerical　simulation　methods.　The　validated　model　is　used　to　simulate　and　predict　the　dynamic　performance　of　LJT-FMHPA-ICSSAH　under　different　heat　transfer　structures.　Several　optimization　parameters,　including　the　air　gap　thickness,　the　optical　properties　of　the　collector　and　glass　cover　plates,　and　fins　structure,　are　considered.　Simulation　results　indicate　that　the　heat　lost　to　the　external　environment　through　the　glass　cover　plate　accounted　for　over　70　%　of　the　total　heat　dissipation.　The　optimal　combination　included　a　50　mm　gas　layer;　copper-based　blue　titanium　coating;　ultra-white　glass;　and　fin　spacing,　thickness,　height,　and　length　of　5,　0.2,　60,　and　195　mm,　respectively.　Under　autumn/winter　operating　conditions,　the　optimized　thermal　performance　is　1.13–1.35　times　higher　than　the　performance　prior　to　optimization.　©　2024　Elsevier　Ltd