Cooling　systems　have　been　widely　used　in　the　industry.　In　order　to　satisfy　cooling　processes　with　large　temperature　ranges,　cascade　cooling　systems　included　different　cooling　methods　have　been　developed.　However,　waste　heat　in　such　processes　could　still　be　recovered　instead　of　being　cooled　down　in　further　operations.　There　are　many　waste　heat　recovery　technologies,　but　a　systematic　method　to　implement　such　technologies　in　a　cascade　cooling　system　optimally　has　not　been　well　studied.　This　paper　presents　a　new　cascade　cooling　system　considering　waste　heat　recovery　via　Organic　Rankine　Cycle　(ORC)　and　absorption　refrigeration　(AR).　An　optimization　method　for　minimizing　the　total　annual　cost　has　been　proposed　to　distribute　the　cooling　duty　for　different　cooling　methods.　A　case　study　is　conducted　to　validate　the　economic　advantages　of　the　proposed　method.　From　the　results,　the　scheme　using　AR　can　reduce　the　total　annual　cost　by　37.5%　and　the　scheme　using　ORC　can　reduce　the　total　annual　cost　by　42.8%.　Results　show　that　in　cases　where　the　heat　source　supply　temperature　is　higher　than　123　°C,　ORC　will　achieve　higher　economic　benefits.　Otherwise,　AR　is　economically　superior　to　ORC.　The　method　can　also　indicate　how　to　distribute　cooling　duty　between　different　cooling　method.　©　2021　Elsevier　Ltd