Latent　heat　recovery　is　a　significant　issue　in　heat　recovery　of　nature　gas,　and　it　can　improve　thermal　efficiency　of　boilers　greatly.　A　scheme　involving　AHPs　(absorption　heat　pumps)　to　generate　cold　water　to　recover　latent　heat　in　flue　gas　is　proposed　and　applied　to　northern　China.　COP　of　AHPs　is　greatly　affected　by　solution　HXs　(heat　exchangers),　so　performance　of　the　HX　cannot　be　too　low.　In　the　article,　a　new　system　is　put　forward,　investment　of　solution　heat　exchanges　can　be　decreased　greatly.　Afterwards,　key　parameters　and　investment　saving　ratio　are　discussed.　Optimal　flue　gas　temperature　drop　in　flue　gas-solution　HXs　is　calculated　and　maximum　of　investment　saving　ratio　is　put　forward.　(C)　2017　The　Authors.　Published　by　Elsevier　Ltd.