A　mechanically-driven　loop　heat　pipe　heat　rec?overy　system　by　booster　and　refrigerant　pump　was　proposed　to　match　the　all-year　fresh　air　load　varying　greatly　with　ambient　temperature　in　an　energy　recovery　ventilation　unit　and　enhance　its　energy-saving　potentials.　The　system　prototype　was　developed　and　the　experimental　setup　established　in　which　the　booster　and　pump　can　operate　together　or　separately.　Namely,　the　prototype　could　be　running　in　pump-driven　loop　heat　pipe　(PLHP)　mode,　booster-driven　loop　heat　pipe　(BLHP)　mode　or　booster　combining　with　pump-driven　loop　heat　pipe　(CLHP)　mode.　The　heat　transfer　characteristics　of　the　prototype　running　in　these　three　modes　under　winter　and　summer　conditions　were　studied,　respectively.　The　results　showed　that　the　temperature　effectiveness　of　CLHP　was　greater　than　that　of　PLHP　or　BLHP　under　all-year　conditions.　When　outdoor　temperature　is　-15　?degrees　C,　the　temperature　effectiveness　of　CLHP　is　78.0%　and　52.5%　higher　than　that　of　PLHP　and　BLHP,　respectively,　and　the　heating　EER　of　CLHP　is　29.6%　higher　than　that　of　BLHP.　When　outdoor　temperature　is　40　?degrees　C,　the　CLHP　has　19.5%　higher　of　temperature　effectiveness　and　21.7%　higher　of　cooling　EER　comparing　with　the　BLHP,　respectively.　In　winter,　BLHP　performs　better　when　outdoor　temperature　is　greater　than　7.5　?degrees　C　while　CLHP　performs　better　when　outdoor　temperature　is　lower　than　7.5　?degrees　C.　And　BLHP　has　better　performance　when　outdoor　temperature　is　lower　than　35　?degrees　C　in　summer　while　CLHP　performs　better　when　outdoor　temperature　is　higher　than　35　?degrees　C.　The　composite　system　can　switch　its　operating　mode　according　to　the　fresh　air　load,　which　can　improve　effectively　the　year-round　performance　of　the　system　to　recover　heat　in　building　ventilation.