Exergy analysis and performance testing of a gravitational water vortex turbine runner for small hydropower plants: An Experimental Approach

their low initial investment, simple design, ease of maintenance, and low head utilization. However, the technology suffers from poor performance issues caused by the non-optimized parameters of its crucial components, such as the runner. In this study, the performance of a runner (16° blade-hub angle, six blades, and a curved blade profile) for a GWVPP was experimentally examined. The study also employed an exergy analysis. The experimental results revealed that the efficiency of the GWVPP system was in the range of 9.84% to 25.35%, the torque was in the range of 0.08 to 0.23 Nm, and the output power was in the range of 2.96 to 7.33 W. Furthermore, an exergy analysis of the system showed an exergy efficiency of 43.58%. Additionally, the error analysis of the GWVPP revealed ranges of 0.1 - 0.5 W for power, 0.01 - 0.03 Nm for torque, and 1.3–3.1% for efficiency, suggesting that the experimental setup and instrumentation of this study were reasonably accurate. Based on the results, the new vortex runner and GWVPP system are recommended for energy generation in low-head, low-flow small hydropower plants. Keywords – Micro-hydropower; gravitational water vortex; runner; exergy efficiency; test rig