R32,　with　an　ozone　depletion　potential　(ODP)　of　zero　and　a　global　warming　potential　(GWP)　of　675,　may　be　an　acceptable　working　fluid　for　refrigeration/heat　pump　systems　to　replace　HFCs.　The　performance　of　an　enhanced　vapor　injection　refrigeration/heat　pump　system　(EVI　system)　was　experimentally　investigated　using　R32.　The　results　show　that　this　system　reduces　the　discharge　temperatures　for　both　cooling　and　heating,　with　the　heating　capacity　of　the　EVI　system　using　R32　3　-　9%　higher　than　that　of　the　single-stage　system.　The　cooling　capacity,　cooling　EER　and　heating　COP　depend　on　the　refrigerant　intermediate　pressure　and　the　operating　conditions　so　they　can　be　bigger　or　smaller　than　for　the　single-stage　system.　The　best　range　of　relative　vapor　injection　mass　is　12　-　16%　for　the　best　overall　cooling　and　heating　performance.　Vapor　injection　changes　the　systems　operating　conditions,　and　increases　both　the　evaporating　and　condensing　temperatures　by　0.8　-　1　degrees　C.　(C)　2013　Elsevier　Masson　SAS.　All　rights　reserved.