Experimental Study on the Organic Rankine Cycle for the Recovery of the Periodic Waste Heat Source

The traditional oil radiator is substituted with the organic Rankine cycle for the recovery of the abundant waste heat in the hydraulic system to improve the overall system efficiency. A prototype of the proposed system is developed to analyze both steady-state and dynamic performance. The effects of oil flow rate and connected load on system performance are studied under steady-state conditions. When the electrical load increases from 60 W to 320 W, the output power of the generator rises from nearly 42 W to 85 W, with the expander–generator efficiency between 15% and 35%. The dynamic experiment is conducted to analyze the variation characteristics of the system performance under the periodic variations in the oil flow. With the oil flow rate changes in the range of 40~80 L/min, the evaporator experiences an oil pressure drop ranging from 3.6 kPa to 18.6 kPa, while the heat transfer rate varies from approximately 2 kW to 5 kW. The influence of different flow frequencies on pressure drop and heat transfer of heat exchangers is also analyzed. The experimental findings can guide the control of operating parameters and enhance the system’s performance.