In　this　part　of　the　investigation,　the　thermal　performance　of　an　integrated　collector　storage　solar　air　heater　(ICSSAH)　on　the　basis　of　a　lap　joint-type　flat　micro-heat　pipe　array　during　simultaneous　charging　and　discharging　mode　is　experimentally　studied.　Paraffin　is　used　as　a　phase　change　material,　and　air　acts　as　a　heat　transfer　fluid　in　a　built-out　structure　of　ICSSAH.　The　thermal　performance　of　ICSSAH　is　assessed　under　an　outdoor　experiment　to　explore　the　effect　of　seasonality,　volume　flow　rate,　and　daily　accumulative　solar　radiation.　Thermal　energy　analysis　is　described　and　calculated　in　detail　according　to　the　experimental　measurements.　Results　showed　that　the　daily　mean　thermal　efficiency　in　summer　is　significantly　higher　than　the　transition　season.　The　smaller　the　volume　flow　rate　is,　the　lower　the　thermal　efficiency　will　be.　However,　the　effect　of　solar　radiation　on　thermal　efficiency　is　small　during　the　test　conditions.　The　highest　daily　thermal　efficiency　at　the　volume　flow　rate　of　141　m(3)/h　is　approximately　78.1%　in　the　present　study　when　the　solar　irradiance　ranges　from　0　W/m(2)　to　874　W/m(2)　and　the　ambient　temperature　varies　from　27.8　degrees　C　to　35.4　degrees　C.　(C)　2019　Elsevier　Ltd.　All　rights　reserved.