On January 30, researchers published findings in the Cell Press journal Joule, indicating that a new, efficient, and eco-friendly refrigeration technology may soon be available. This innovation relies on thermogalvanic cells that create a cooling effect through a reversible electrochemical reaction. Thermogalvanic refrigeration is not only more affordable but also better for the environment compared to traditional cooling methods, as it requires significantly less energy. Its versatile nature means it could be applied to a wide range of uses, from personal cooling devices to industrial systems.
Jiangjiang Duan, a senior author from Huazhong University of Science and Technology in Wuhan, China, states, “Thermogalvanic technology is set to become part of our lives, either as clean electricity or low-energy cooling solutions, and both research and commercial sectors should take notice.”
Thermogalvanic cells harness heat generated by reversible electrochemical reactions to produce electricity. By reversing this method—applying an external electrical current to initiate electrochemical reactions—cooling power can be generated. Earlier research suggested that thermogalvanic cells had limited cooling capacity, but Duan’s team dramatically enhanced this potential by refining the chemicals involved in the process.
Duan explains, “While past research mainly focused on the initial system design and numerical simulations, we present a logical and universal design strategy for thermogalvanic electrolytes, achieving an unprecedented cooling performance that is ready for practical use.”
The cooling cells utilize electrochemical redox reactions with dissolved iron ions. During one part of the reaction, iron ions release an electron and absorb heat (Fe3+ → Fe2+), while in another part, they accept an electron and release heat (Fe2+ → Fe3+). The cooling effect comes from the heat absorbed during the first reaction, while a heat sink removes the heat generated in the second reaction.
By adjusting the solutes and solvents in the electrolyte solution, the researchers significantly enhanced the cooling capability of the hydrogalvanic cell. They employed a hydrated iron salt containing perchlorate, which allowed the iron ions to dissolve and separate more effectively than other previously studied iron salts, like ferricyanide. By using a nitrile-based solvent instead of pure water, they increased the cooling capacity of the hydrogalvanic cell by 70%.
The improved system managed to cool the surrounding electrolyte by 1.42 K, showcasing marked advancement compared to the mere 0.1 K capacity of earlier thermogalvanic systems.
In the future, the team aims to further refine their system’s design and explore potential commercial uses.
Duan remarks, “While our enhanced electrolyte is feasible for commercial use, additional effort is needed in system-level design, scalability, and stability to facilitate practical applications of this technology. We plan to continue enhancing thermogalvanic cooling performance by investigating new mechanisms and advanced materials. We are also focused on developing various refrigerator prototypes for potential applications and are eager to partner with innovative companies to advance the commercialization of thermogalvanic technologies.”
