Refrigerators and freezers typically derive their cooling power from environmentally harmful liquids.
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A new type of crystal could help refrigerators and air conditioners keep us cool without warming the planet.
Refrigerators and air conditioners obtain their cooling power by circulating liquid within the device. The liquid absorbs heat and causes cooling through cycles of evaporation and condensation. However, many such liquids contribute to the greenhouse effect and cause further warming if they leak. Now, Jenny Pringle and colleagues at Australia’s Deakin University have developed a climate alternative to these liquids using “plastic crystals” – crystals that can move around enough to make molecules flexible. We have developed a friendly alternative.
If enough pressure is applied, these plastic crystals can deform. Their molecules go from a random orientation to an ordered grid. Then, when the pressure is removed, they disturb again. As part of this disordering process, the crystals absorb heat, effectively cooling their surroundings.
Although pressure-based cooling like this has been studied before, most materials capable of this transition can only do so at mild temperatures, limiting their cooling power, Pringle said. In contrast, her team’s crystals exhibit their heat-absorbing ability at temperatures between -37°C (-34.6°F) and 10°C (50°F), a temperature suitable for home refrigerators and freezers. .
However, the new crystals are not yet ready to leave the lab. That’s because the pressure needed to make them work is so high, Pringle says, that it’s hundreds of times greater than atmospheric pressure and equivalent to thousands of meters underwater.
David Boldrin, from the University of Glasgow in the UK, said materials like the one in the study “have the potential to almost completely decarbonize this huge (refrigeration) industry”, but the needed The concerns about high pressure are the same.
There may be other practical problems with this approach, says Bing Li of the Chinese Academy of Sciences. With each repeated use, the grid formed by the molecules becomes more distorted and each crystal absorbs less heat. Still, Lee said he was optimistic and believed the technology could be applied in the “near future.”
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