Refrigerators and freezers usually get their cooling power from fluids that are harmful to the environment
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A new type of crystal can enable it refrigerators and air conditioners to stay cool without warming the planet.
Refrigerators and air conditioners achieve their cooling capacity by circulating a liquid through the device, which absorbs heat and causes cooling through a cycle of evaporation and condensation. But many such liquids they contribute to the greenhouse effect, causing more warming when they are released. now, Jenny Pringle At Deakin University in Australia and his colleagues, they have made an alternative to these liquids using “plastic crystals”, crystals with molecules that can move enough to be flexible.
With enough pressure, these plastic crystals can be transformed. Their molecules go from being randomly oriented to aligning in a neat network. Then, when the pressure is removed, they become disordered again. As part of this disordering process, the crystals absorb heat, effectively cooling the environment.
Such pressure-based cooling has been studied before, but most materials capable of making this transition can only do so at cool temperatures, limiting their cooling capacity, Pringle says. In contrast, the heat-absorbing ability of crystals in its group falls within the temperature range of -37°C (-34.6°F) to 10°C (50°F), a suitable range for household refrigerators and freezers.
However, the new crystals aren’t ready to leave the lab yet. That’s because the pressures required to operate are so high, hundreds of times greater than atmospheric pressure and equivalent to being thousands of meters underwater, Pringle says.
David Boldrin At the University of Glasgow in the UK, he says materials like those in the new study have the potential to “decarbonize this giant (refrigeration) industry almost completely,” but shares concerns about the high pressures it would require.
He says there may be another practical problem with this approach Bing Lee in the Chinese Academy of Sciences. With repeated use, each crystal can absorb less heat as the network of molecules becomes tighter. However, Li is optimistic and says he is confident the technology will be applied “in the near future”.
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