Torsional refrigeration by twisted, coiled, and supercoiled fibers
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Twisted wires could provide a more efficient and environmentally friendly way to cool refrigerators.
Air conditioners and fridges are ubiquitous, but keeping things cool currently relies on harmful greenhouse gases and a lot of electricity.
A team that included researchers from Nankai University investigated the cooling effect of releasing twisted and coiled strands of stretchy materials such as rubber and fishing line. They found that rapid release of twisted rubber caused up to 15.5 degrees Celsius of cooling, and that by coiling fishing line in the opposite direction to the twists, the material cooled when stretched.
The team built a prototype ‘twist fridge’ using a twisted nickel–titanium strand inserted through a plastic tube with water flowing through. Releasing the twist just once cooled the water by nearly 5 degrees Celsius.
The researchers calculated that nickel–titanium twist fridges could be up to 10% more energy efficient than conventional fridges.
- Science 366, 216–221 (2019). doi: 10.1126/science.aax6182