Latent　heat　thermal　storage　(LHTS)　system　is　a　vital　way　to　recover　waste　heat　for　energy　saving.　However,　phase　change　materials　(PCMs)　with　low　thermal　conductivity　severely　limit　the　energy　storage　efficiency.　A　novel　LHTS　tank　with　multi-channels　filled　with　metal　foams　is　designed　to　improve　the　overall　heat　storage　efficiency.　Further,　a　three-dimensional　phase　transition　model　is　developed,　with　particular　concerns　paid　on　the　filling　pattern　of　metal　foam　in　HTF,　PCM,　and　both.　The　numerical　model　can　better　reveal　the　synergistically　enhanced　heat　transfer　and　conduction　mechanism　of　heat　transfer　fluid　(HTF)　and　PCM　with　metal　foam.　The　numerical　model　is　verified　with　the　existing　experimental　data,　and　a　satisfactory　agreement　is　obtained.　Four　filling　methods　are　designed,　in　which　the　porosity　and　pore　density　of　metal　foam　is　0.93　and　15　pore　per　inch,　respectively.　Compared　with　the　non　porous　tank,　the　phase　transition　time　can　be　reduced　by　23.7%　for　PCM　filled　with　metal　foam;　while　filling　HTF　with　metal　foam　reduces　the　melting　time　by　58.3%.　The　synergized　effect　of　filling　both　reduces　melting　time　by　77.6%.　The　heat　flow　into　PCM　is　increased　when　metal　foam　is　in　HTF.　Further,　when　metal　foam　is　in　PCM,　the　temperature　uniformity　of　PCM　is　augmented　and　its　phase　transition　isothermal　duration　is　prolonged.　The　assessment　options　can　provide　scientific　design　guidance　for　improving　the　thermal　storage　efficiency　of　LHTS　tank.　©　2022