To　take　full　advantage　of　the　waste　heat　from　a　diesel　engine,　a　set　of　dual　loop　organic　Rankine　cycle　(ORC)　system　is　designed　to　recover　exhaust　energy,　waste　heat　from　the　coolant　system,　and　released　heat　from　turbocharged　air　in　the　intercooler　of　a　six-cylinder　diesel　engine.　The　dual　loop　ORC　system　consists　of　a　high　temperature　loop　ORC　system　and　a　low　temperature　loop　ORC　system.　R245fa　is　selected　as　the　working　fluid　for　both　loops.　Through　the　engine　test,　based　on　the　first　and　second　laws　of　thermodynamics,　the　performance　of　the　dual　loop　ORC　system　for　waste　heat　recovery　is　discussed　based　on　the　analysis　of　its　waste　heat　characteristics　under　engine　various　operating　conditions.　Subsequently,　the　diesel　engine-dual　loop　ORC　combined　system　is　presented,　and　the　effective　thermal　efficiency　and　the　brake　specific　fuel　consumption　(BSFC)　are　chosen　to　evaluate　the　operating　performances　of　the　diesel　engine-dual　loop　ORC　combined　system.　The　results　show　that,　the　maximum　waste　heat　recovery　efficiency　(WHRE)　of　the　dual　loop　ORC　system　can　reach　5.4%　under　engine　various　operating　conditions.　At　the　engine　rated　condition,　the　dual　loop　ORC　system　achieves　the　largest　net　power　output　at　27.85　kW.　Compared　with　the　diesel　engine,　the　thermal　efficiency　of　the　combined　system　can　be　increased　by　13%.　When　the　diesel　engine　is　operating　at　the　high　load　region,　the　BSFC　can　be　reduced　by　a　maximum　4%.　Crown　Copyright　(C)　2014　Published　by　Elsevier　Ltd.　All　rights　reserved.