Performance Evaluation of a Diffuser-Augmented Horizontal Axis Wind Turbine for Energy Generation in Low-Wind Environments

Abstract

This study evaluated the performance of a Diffuser-Augmented Horizontal Axis Wind Turbine (DAHAWT) as a renewable energy source for low-wind environments in Poblacion West, Santo Tomas, Pangasinan, Philippines. Conventional Horizontal Axis Wind Turbines (HAWTs) generally require higher cut-in wind speeds, limiting their effectiveness in rural and semi-urban areas with inconsistent wind resources. To address this limitation, a flanged diffuser with an inlet shroud was integrated into a small-scale HAWT to enhance airflow concentration and improve energy generation efficiency. A descriptive-experimental and comparative research design was employed through the fabrication and field testing of both HAWT and DAHAWT systems under identical operating conditions. Wind speed, rotor rotational speed (RPM), voltage output, and battery charging performance were measured using a digital anemometer, tachometer, and voltmeter. Results showed that the DAHAWT achieved a significantly lower cut-in wind speed of approximately 1.62–1.70 m/s compared with 2.5–3.0 m/s for the conventional HAWT. The DAHAWT also produced substantially higher RPM and voltage output, with paired-sample t-tests confirming significant differences in RPM, t(143) = −16.58, p < 0.001, and voltage generation, t(143) = −16.17, p < 0.001. Regression analysis further demonstrated that wind speed strongly predicts turbine RPM and voltage output, with coefficients of determination of approximately R² = 0.82. Battery charging analysis likewise revealed that the DAHAWT achieved more frequent and sustained charging operation under similar wind conditions. Overall, the findings confirm that diffuser augmentation significantly enhances the aerodynamic and electrical performance of small-scale wind turbines, demonstrating the feasibility of DAHAWT systems as cost-effective and sustainable renewable energy solutions for low-speed wind applications.