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.