Researchers hope that ionocaloric refrigeration could one day replace high global warming potential refrigerants and provide safe and efficient heating and cooling for homes.
Adding salt to roads before winter storms causes ice to form. Researchers at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have applied this basic concept to develop new methods of heating and cooling. The technology they named “ion calorie cooling” paper Published in the journal December 23 chemistry.
Ionocaloric cooling exploits how energy or heat is stored and released when a material undergoes a phase change, such as from solid ice to liquid water. When a substance melts, it absorbs heat from its surroundings, and when it solidifies, it releases heat. The ionocaloric cycle causes this phase and temperature change via the flow of ions (charged atoms or molecules) originating from the salt.
Researchers believe that this method could one day provide efficient heating and cooling, accounting for more than half of the energy used in homes, surpassing today’s “vapor compression,” which uses gases with high global warming potential as refrigerants. We hope that it will help us phase out the system. Ionic caloric cooling eliminates the risk of escaping into the atmosphere by replacing such gases with solid and liquid components.
“The refrigerant situation is an open question. No one has succeeded in developing an alternative solution that cools things, works efficiently, is safe, and does not harm the environment,” said a graduate research assistant at Berkeley Lab. Yes, PhD candidate at UC Berkeley who led this research. “We believe that the ionocaloric cycle, if implemented properly, has the potential to achieve all these goals.”
Finding solutions to replace current refrigerants is essential for countries to meet climate change goals such as the Kigali Amendment (approved by 145 Parties including the United States in October 2022). am. The agreement commits signatories to reduce hydrofluorocarbon (HFC) production and consumption by at least 80% over the next 25 years. HFCs are powerful greenhouse gases, commonly found in refrigerators and air conditioning systems, and can trap heat thousands of times more effectively than carbon dioxide.
The new Ionic Caloric Cycle joins several other types of “caloric” cooling in development. These technologies use various methods such as magnetism, pressure, stretching and electric fields to manipulate solid materials to absorb or release heat. Ionic calorimetric cooling differs in that it uses ions to drive the phase change from solid to liquid. Using a liquid has the added benefit of making the material pumpable, making it easier to move heat in and out of the system. This is what solid cooling has struggled with.
Lilley and co-author Ravi Prasher, a research collaborator in the Energy Technology field at Berkeley Lab and adjunct professor of mechanical engineering at the University of California, Berkeley, presented the theory underlying the ionocaloric cycle. They calculated that it could compete with or even exceed the efficiency of gas refrigerants found in most systems today.
They also demonstrated this technology experimentally. Lilly used a salt made of iodine and sodium along with ethylene carbonate, a common organic solvent used in lithium-ion batteries.
“There may be refrigerants that are not just GWP. [global warming potential]- zero, but the GWP is negative,” Lilly said. “Using a material like ethylene carbonate can actually be carbon negative because it produces carbon dioxide as an input.2 from carbon capture. ”
Passing an electric current through the system causes the ions to migrate and change the melting point of the material. When it melts, it absorbs heat from its surroundings, and when it solidifies due to the release of ions, it returns heat. Initial experiments showed a temperature change of 25 degrees Celsius using less than 1 volt. This is a greater temperature rise than has been demonstrated by other calorimetric techniques.
“We are trying to balance three things: the GWP of the refrigerant, the energy efficiency, and the cost of the equipment itself,” says Prasher. “From the first try, our data, these he looks very promising on all three sides.”
Caloric methods are often discussed in terms of cooling capacity, but cycles can also be used in applications such as hot water and industrial heating. The ionocaloric team continues prototype work to determine how to scale this technology to support bulk cooling, improve the amount of temperature change the system can support, and improve efficiency. I’m here.
“We have this whole new thermodynamic cycle and framework that brings together elements from different disciplines and we have shown that it works,” said Prasher. “Now is the time to experiment to test different combinations of materials and technologies to meet engineering challenges.”
Lilley and Prasher have a provisional patent for an ionocaloric refrigeration cycle, and the technology is now available for licensing by contact. [email protected].
Original: Berkeley Lab Scientists Develop Cool New Ways to Refrigerate
Than: Lawrence Berkeley National Laboratory
