Science & Technology, (Commonwealth Union) – In ionocaloric cooling, the cooling effect is achieved through the reversible migration of ions (positively or negatively charged atoms or molecules) within a solid material. When an electric field is applied to the material, the ions move from one side of the solid to the other, absorbing heat in the process, and causing a cooling effect. This effect is known as the “caloric effect.”
The principle behind ionocaloric cooling is similar to other solid-state cooling technologies such as magnetocaloric cooling and elastocaloric cooling, which use magnetic and mechanical stress, respectively, to induce cooling in certain materials.
The potential advantages of ionocaloric cooling include its environmentally friendly nature (no greenhouse gases or harmful chemicals are involved), higher efficiency compared to traditional vapor compression refrigeration systems, and potentially quieter operation since it lacks moving parts like compressors.
Researchers have utilized the method “ionocaloric cooling,” inspired by the concept of adding salt to roads to prevent ice formation. This innovative technique utilizes the transfer of ions within a salt to induce phase and temperature changes, leading to efficient heating and cooling effects.
The ionocaloric cycle operates on the principle that when a material changes phase, such as from solid ice to liquid water, it either absorbs or releases heat. By controlling the flow of ions (charged atoms or molecules) in a salt, researchers can drive these phase changes to achieve cooling or heating effects. This cycle holds the potential to replace current “vapor compression” systems that use refrigerants with high global warming potential.
“The landscape of refrigerants is an unsolved problem: No one has successfully developed an alternative solution that makes stuff cold, works efficiently, is safe, and doesn’t hurt the environment,” said Drew Lilley, a graduate research assistant at Berkeley Lab and PhD candidate at UC Berkeley who led the study. “We think the ionocaloric cycle has the potential to meet all those goals if realized appropriately.”
As many homes consume over half of their energy for heating and cooling purposes, finding environmentally friendly alternatives to conventional refrigerants becomes crucial for meeting climate change goals. The ionocaloric cycle could be a promising solution as it avoids harmful greenhouse gases by employing solid and liquid components instead.
The development of ionocaloric cooling aligns with the Kigali Amendment, wherein countries commit to reducing the production and consumption of hydrofluorocarbons (HFCs), potent greenhouse gases commonly found in refrigeration and air conditioning systems.
The ionocaloric cycle represents one of several “caloric” cooling techniques in development. By using ions to drive phase changes, the material becomes pumpable, making it more efficient to transfer heat in or out of the system compared to traditional solid-state cooling methods.
Experiments have shown promising results, with a temperature change of 25 degrees Celsius achieved using less than one volt of electricity. The researchers believe that ionocaloric cooling has a great possibility to take on, or even surpass the efficiency of gaseous refrigerants used right now.
The system utilizes a salt formed with iodine and sodium, combined with ethylene carbonate, a common organic solvent used in lithium-ion batteries. Running electric current through the system moves the ions, changing the material’s melting point, resulting in heat absorption during melting and heat release upon solidification.
The team is continuing their work on prototypes to explore how ionocaloric cooling can be scaled up for large-scale cooling applications, improve the system’s temperature change capabilities, and enhance overall efficiency. They have received a provisional patent for the technology and are open to licensing opportunities for its implementation.
Overall, ionocaloric cooling offers an exciting potential for providing safe, efficient heating and cooling solutions that could benefit homes and industries while addressing environmental concerns associated with traditional refrigerants.
