The　operating　temperature　influences　both　the　electrical　efficiency　and　thermal　efficiency　of　a　photovoltaic　thermal　(PVT)　module.　In　this　paper,　a　simplified　thermal　transfer　model　is　used　to　search　for　the　optimal　structure　of　a　high　efficiency　PVT　module.　For　an　aluminum　collector　with　a　given　thickness,　the　optimal　ratio　between　size　and　spacing　and　cross　sectional　geometry　of　the　flow　channels　has　been　found　with　numerical　simulations　using　computational　fluid　dynamics　(CFD).　The　temperature　distribution　of　the　PVT　module　constructed　with　an　aluminum　collector　is　found　to　be　more　uniform　than　the　conventional　sheet-tube　PVT　module,　due　to　using　an　improved　thermal　transfer　mode　based　on　the　surface　contact.　To　evaluate　the　impact　of　cross　sectional　geometry,　the　operating　temperatures,　electrical　and　thermal　efficiencies　of　two　PVT　modules　designed　with　rectangle　and　arch　geometries　are　examined　under　outdoor　conditions.　Measured　experimental　intercept　values　of　instantaneous　thermal　efficiencies　are　close　to　simulation　results,　demonstrating　the　utility　of　the　approach　as　a　reference　for　a　new　generation　of　PVT　modules　in　future.　(C)　2020　Elsevier　Ltd.　All　rights　reserved.