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The surplus water head at industrial cooling towers is generally 4 to 15 meters. Using the surplus water head, a Francis turbine with super-low specific speed was designed to replace the fan motor in the cooling tower for energy saving. Based on the features of the surrounding environment, the runner blade airfoil was designed and optimized with 3-D numerical simulation through the whole flow passage of the turbine. Metal elliptical volutes and single-row ring guide vanes were applied in the structural design. After analyzing the numerical simulation results, an optimal model of 86% efficiency was selected for the physical model. The model test showed that the super-low specific speed Francis turbine met the dimensional requirement and had a high efficiency of 85.3%. Its stable performance can be popularized and applied in the capable local facilities.