A team of scientists from the Karlsruhe Institute of Technology in Germany and the University of Tsukuba in Japan has developed a cooling system that uses heat to produce cold without relying on electric motors. The technology employs two ultrathin films made from a nickel-titanium shape-memory alloy capable of converting thermal energy into mechanical movement and, subsequently, into refrigeration.
The system is based on the so-called elastocaloric effect, a phenomenon that occurs when certain materials undergo mechanical deformation and exhibit reversible temperature changes. Currently, systems such as refrigerators, air-conditioning units, and cooling equipment for data centres generally use electrically driven compressors to transfer heat from one location to another.
In the new concept, the researchers seek to replace the electric motor with a heat source. The prototype uses two nickel-titanium films that perform different and complementary functions.
The first film acts as a thermal actuator. When heated, the shape-memory alloy contracts, directly converting heat into mechanical work. This movement is transmitted to the second film, which is subjected to loading and unloading cycles. The process triggers reversible changes in the metal’s crystalline structure, producing the elastocaloric effect and, consequently, cooling.
In this way, heat takes on the role normally assigned to the electric motor. According to the team, the combination of these two functions makes it possible to develop a new solid-state cooling approach with the potential to harness heat sources that would otherwise be wasted.
In tests, the prototype achieved a temperature differential of approximately 4°C at the component level when the actuator was heated to 86°C. In the elastocaloric material, the temperature variation reached nearly 13°C. The system was also able to operate using an external heat source at 130°C, demonstrating that the concept can function with real thermal sources.
Potential applications include the cooling of processors and other electronic components, including scenarios in which the heat generated by the equipment itself could be reused to activate the system. The technology could also be deployed in vehicles, harnessing heat from the propulsion system and transmission to cool sensitive electronic components.
The study, entitled ‘Heat-driven elastocaloric cooling with shape memory films’, was published in the scientific journal Nature Energy. The researchers believe the technology could pave the way for more compact cooling systems capable of using waste heat or solar energy as a power source to produce cold.
Source: Diário Económico
Original article: https://www.diarioeconomico.co.mz/?p=545841
