Scientists develop first-of-its-kind air conditioner that uses solid refrigerants

Now, cooling an environment needs an enormous amount of energy. Our energy grids primarily rely on fossil fuels, and any energy that is used to reduce temperature emits greenhouse gases. Refrigerants, chemicals that are used to reduce temperatures, have high global warming potential. When these leak out into the atmosphere, it massively impacts the climate. The hydrofluorocarbon refrigerants in these and other cooling devices are potent greenhouse gases and major drivers of climate change.

Therefore, we must start looking for environmentally-friendly solutions before it’s not too late.

Now, scientists have created a prototype device that could someday replace existing “A/Cs”. The new version is more environmentally friendly and uses solid refrigerants to cool a space, according to a release.

The researchers presented their results at the fall meeting of the American Chemical Society.

“Just installing an air conditioner or throwing one away is a huge driver of global warming,” said Adam Slavney, Ph.D., who presented the work at the meeting.

Scientists develop first-of-its-kind air conditioner that uses solid refrigerants

A prototype cooling system uses new solid-state barocaloric materials.

Traditional cooling systems, such as air conditioners, work by causing a refrigerant to cycle between being a gas or a liquid. When the liquid becomes a gas, it expands and absorbs heat, cooling a room. A compressor that works at about 70–150 pounds per square inch (psi) turns the gas back into a liquid, releasing heat.

With air conditioners, this heat is directed outside the home. This cycle seems effective but concerns about climate change and strict regulations on hydrofluorocarbon refrigerants are triggering the search for more environmentally responsible ones.

An ideal solution could be solid refrigerants as, unlike gases, they wouldn’t leak into the environment from A/C units. The researchers found that barocaloric materials, a class of solid refrigerants, work similarly to traditional gas-liquid cooling systems. Though they use pressure to go through heat cycles, it drives a solid-to-solid phase change.

Barocaloric solid materials comprise long, flexible molecular chains that are “typically floppy and disordered” but under pressure, they become more ordered and rigid – releasing heat. According to Jarad Mason, Ph.D., the project’s principal investigator, who is at Harvard University, the process of going from an ordered to a relaxed structure is like melting wax, but without it becoming a liquid. When that pressure is released, the material reabsorbs heat, completing the cycle.

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