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<\/div>Refrigerators and freezers typically get their cooling power from environmentally harmful fluids<\/p>\n
Mint Images Limited\/Alamy<\/p>\n<\/div>\n<\/figcaption><\/figure>\n<\/p>\n
A new type of crystal could enable refrigerators<\/a> and air conditioners<\/a> to keep us cool without warming the planet.<\/p>\n Refrigerators and air conditioners get their cooling power by circulating a liquid through the device, which absorbs heat and causes chilling through a cycle of evaporation and condensation. But many such liquids<\/a> contribute to the greenhouse effect, causing further warming when they leak. Now, Jenny Pringle<\/a> at Deakin University in Australia and her colleagues have made a climate-friendly alternative to these liquids using \u201cplastic crystals\u201d \u2013 crystals with molecules that can move just enough to make them pliable.<\/p>\n Under enough pressure, these plastic crystals can transform. Their molecules go from being randomly oriented to aligning themselves into a neat grid. Then, when pressure is removed, they become disordered again. As part of this disordering process, the crystals absorb heat, effectively cooling their surroundings.<\/p>\n Such pressure-based cooling has been investigated before, but most materials capable of this transition could only do so at balmy temperatures, limiting their cooling power, says Pringle. In contrast, the heat-sucking ability of her team\u2019s crystals kicks in at temperatures from -37\u00b0C (-34.6\u00b0F) to 10\u00b0C (50\u00b0F), a suitable range for household refrigerators and freezers.<\/p>\n <\/p>\n However, the new crystals are not ready to leave the lab yet. That\u2019s because the pressures needed to make them work are very high \u2013 hundreds of times greater than atmospheric pressure and equivalent to being thousands of metres underwater, says Pringle.<\/p>\n David Boldrin<\/a> at the University of Glasgow, UK, says materials like those in the new study have \u201cthe potential to almost completely decarbonise this huge [cooling] industry\u201d, but he shares the concern about the high pressures required.<\/p>\n There may be another practical issue with this approach, says Bing Li<\/a> at the Chinese Academy of Sciences. With every repeated use, each crystal may absorb less heat, as the grid the molecules form becomes more strained. Still, Li is optimistic and says he is confident the technology could be applied in the \u201cnear future\u201d.<\/p>\n Topics:<\/p>\n<\/section><\/div>\n