A　single-screw　expander　with　155　mm　diameter　screw　has　been　developed.　A　spiral-tube　type　evaporator　and　an　aluminum　multi-channel　parallel　type　condenser　have　also　been　developed　with　weight　of　147　kg　and　78　kg,　respectively.　Based　on　the　development　of　above　components,　an　ORC　(organic　Rankine　cycle)　system　prototype　was　assembled　and　tested　for　waste　heat　recovery　from　diesel　engine　exhaust.　An　experimental　system　was　built　for　this　ORC　system,　and　experiments　were　conducted　for　different　expander　torque　and　diesel　engine　loads.　Influences　of　expander　torque　and　diesel　engine　loads　on　the　performances　of　ORC　system　were　studied.　The　results　indicated　that　the　maximum　of　the　power　output　is　10.38　kW　and　the　biggest　ORC　efficiency　and　overall　system　efficiency　are　respectively　6.48%　and　43.8%,　which　are　achieved　at　250　kW　of　diesel　engine　output　Meanwhile　the　biggest　improvement　of　overall　system　efficiency　is　1.53%.　The　maximums　of　volume　efficiency,　adiabatic　efficiency　and　total　efficiency　of　single-screw　expander　are　90.73%,　73.25%　and　57.88%,　respectively.　(C)　2014　Elsevier　Ltd.　All　rights　reserved.