Experimental study on the performance of a great progress 10 kW organic Rankine cycle for low-grade heat source based on scroll-type expander

Based on the experimental experience of the previous 3 kW and original 10 kW organic Rankine cycle (ORC) systems, an improved 10 kW ORC experimental prototype using a scroll-type expander is built incorporating improvements to the lubricant oil loop and expander. The heat source temperature is 120 degrees C, while the heat supply is in range of 34-77 kW. The effects of heat supply, expander pressure difference, and degree of superheat on net power and net power-generating efficiency are discussed, and a comparison between the improved 10 kW ORC system and the original 10 kW ORC system is conducted. Results indicate that the net power and net powergenerating efficiency exhibit a sharp increasing trend with the expander pressure difference for a certain mass flow rate, and the optimum degree of superheat for achieving the highest net power of 4.0 kW is found to be 10 degrees C. The improved 10 kW ORC system achieves an optimal net power-generating efficiency of 7.9%, which is 72.11% higher than the original 10 kW ORC system of 4.59%. Compared to the original 10 kW ORC system, the improved 10 kW ORC system achieves a net power increase of 188.79%-414.29% and a net power-generating efficiency improvement of 178.34%-416.89%. This study provides a guide for the design of the ORC experimental prototype, and has important academic significance and application value for enhancing the system efficiency.