A Comprehensive Review of Wind Energy Recovery from Cooling Towers Using Integrated Wind Turbine Systems

Abstract: A cooling tower is an inescapable piece of industrial and power-generation equipment the world over and constantly deposits vast amounts of warm and humidified air up the tower stacks at a rate of between 3 and 12 m/s. This upward-flowing airstream, which is a focused and predictable source of kinetic energy, has long been ignored as a potential source of wind energy recovery. This is a comprehensive review that summarizes the existing body of research on integration of wind turbine systems, which are mainly axial-flow turbines, cross flow turbines and hybrids, into or onto cooling tower buildings with the aim of producing electrical power. We discuss the thermodynamic properties of cooling tower exhaust plumes, the aerodynamic design limits of humid and thermally stratified airstreams, the mechanical and structural issues of turbine placement under wet environments and the empirical and theoretical energy output of pilot and commercial installations, based on over 80 peer-reviewed literatures, engineering reports, and patent analyses published between 1998 and 2025. Important results have shown that properly designed integrated wind turbines can recapture between 2 and 14 percent of the overall fan energy used by a mechanical draft cooling tower, and that theoretical recoverable power densities of 150-800 W/m2 of rotor swept area are possible with respect to exhaust velocity, turbine diameter and placement geometry. Economic estimates indicate that simple payback times are 4 to 12 years with good conditions, with the lifecycle CO2 avoidance of 15-85 tonnes per turbine-year. The review points to several research gaps such as the long-term impact of corrosive and high-humidity conditions on turbine materials, the role of variable thermal loading on turbine operation, and the necessity of having standardized testing procedures. Future research directions, design optimization strategies and policy frameworks are suggested to speed up deployment.