This　study　aims　to　investigate　the　heat　recovery　characteristics　of　a　new-type　flat　micro-heat　pipe　array　heat　exchanger　using　delta-Al2O3-R141b　nanofluids　as　working　fluids.　delta-Al2O3-R141b　nanofluids　with　volume　fractions　of　0.001%,　0.01%,　and　0.1%　were　prepared.　The　experiments　were　performed　with　air　volume　flow　rates　ranging　from　60　m(3)/h　to　120　m(3)/h.　The　evaporator　section　inlet　air　temperature　varied　from　27　degrees　C　to　40　degrees　C　while　the　condenser　section　inlet　air　temperature　remained　at　24　degrees　C.　The　results　indicated　that　heat　recovery　efficiency　is　enhanced　remarkably　by　using　0.01%　volume　fraction　nanofluid　as　working　fluid,　and　the　maximum　growth　rate　of　effectiveness　can　reach　110%.　The　heat　recovery　effectiveness　of　the　0.001　vol%　nanofluid　was　almost　similar　to　that　of　R141b;　however,　the　efficiency　of　0.1%　nanofluid　declined　significantly.　The　pressure　drop　ratio　of　the　heat　exchanger　was　tested　subsequently,　and　the　energy　saved　by　the　exchanger　was　analyzed　to　further　evaluate　the　performance　of　heat　exchanger.　(C)　2013　Elsevier　Ltd.　All　rights　reserved.