Rotational Optimization for Thermal and Renewable Energy Recovery (ROTAR)

Cooling tower fans are critical components in power plants, industrial facilities, and data centers, operating continuously to maintain optimal temperature regulation. With an estimated 100,000 cooling towers worldwide housing millions of fans, these systems consume approximately 500 terawatt-hours (TWh) of electricity annually, representing about 2% of global electricity consumption—sufficient to power entire nations such as Argentina or the Netherlands. ROTAR—Rotational Optimization for Thermal and Renewable Energy Recovery—investigates the feasibility of integrating a belt-driven generator motor within the drivetrains of electric vehicles (EVs), employing architectures similar to those of rotational modules within cooling towers to convert rotational energy into usable electrical power. A scaled prototype was developed in which a secondary motor, driven by the primary axle through a belt mechanism, generates direct current (DC) that is stabilized using a buck-boost converter before being stored in a reserve battery following continuous rotation above a specified threshold. Experimental data demonstrate that during a 20-minute drive cycle, the system recovers 0.2 watt-hours (Wh) of energy, resulting in a 7.91% enhancement in energy efficiency. Over a series of twelve 20-minute drive cycles, the system has the capability to fully recharge a single battery (2.53 Wh). When projected to the average annual driving duration of a typical American, this translates to potential energy savings of 219 Wh, equivalent to 86.56 complete battery cycles per year. As a prototype for industrial-level cooling systems, ROTAR represents a significant advancement in the future of regenerative energy with large-scale global impacts.