A thermal actuator that uses the power of phase change material to displace fluids and perform work is a finalist in the 2018 Hackaday Prize competition.
The actuator, designed by Andrew Benson of Denver, Colo., is competing in the power harvesting category. The challenge: Build a module that harvests ambient power and show the module powering a project. Benson's actuator retracts and expands as the PCM freezes or melts. The concept is described on the competition's website, hackaday.com.
"Thermal actuators are generally inefficient, but extraordinarily reliable," Benson wrote in his contest entry. "This inefficiency can be overlooked when the thermal actuator is powered by waste or ambient heat. They are often used as thermal feedback mechanisms, such as the wax thermostat found in many water cooled engines. Environmental control systems can be created where a thermal actuator reacts to the environment, such as a shade device that deploys when ambient temperature rises above the melting temperature of the PCM."
The five Hackaday Prize winners will be announced at the Hackaday Superconference in early November. The grand prize: $50,000.