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

Abstract

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 °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 power-generating 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 °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.