Latent　heat　thermal　energy　storage(LHTES)　unit　are　an　effective　technical　means　to　balance　the　demand　and　supply　of　energy.　To　enhance　the　heat　transfer　efficiency　of　the　phase　change　material(PCM)　in　the　LHTES　unit,　a　series　of　novel　three-tube　heat　exchangers　with　longitudinal　fins　was　designed.　The　study　was　carried　out　in　terms　of　the　number,　length,　thickness,　and　arrangement　of　fins.　Results　demonstrate　that　the　thickness　change　of　fins　has　a　significant　effect　on　reducing　the　melting　time　of　the　whole　PCM.　The　thin　long　fins　have　a　higher　melting　rate.　The　complete　melting　time　of　the　thin　long　fins　was　10.6　%　faster　than　that　of　the　short　thick　fins.　By　studying　the　effect　of　fin　length　on　the　heat　storage　performance,　it　was　found　that　the　structure　appeared　to　be　more　reasonable　at　L　=　30　mm　and　the　heat　storage　time　was　shortened　by　18.0　%.　In　addition,　the　use　of　the　lower　long　and　upper　short　fin　arrangement　can　strengthen　the　heat　transfer.　Considering　that　the　amount　of　heat　storage　capacity　decreases　as　the　number　of　fins　increases,　N　=　20　is　considered　as　the　best　fin　number.　Therefore,　we　give　an　optimal　combination　of　fin　design　parameters　(N　=　20,　L　=　30,　W　=　1),　which　shortens　the　total　melting　time　of　PCM　by　71.2　%.　To　be　conclusive,　it　is　more　beneficial　to　add　fins　to　heat　transfer　enhancement　than　to　have　no　fins,　saving　more　energy　charging　time.