New Cooling Device Reduces Toxic Emissions From Fridges and Air Conditioners

New cooling technology has been developed by scientists at Cambridge that can be used in refrigerators and air conditioners to replace the existing gases used in almost all fridges and air conditioners that are toxic greenhouse gases. The device is composed of material containing oxygen and three metallic elements known as PST, and has been found to display the greatest electrocaloric effect, i.e., change in temperature produced in response to an electric field.

The findings of the study appear in the journal Nature and could pave the way for developing highly effective solid-state (i.e., without gases) refrigerators and air conditioners, overcoming the need to use expensive and heavy magnets.

"When facing a challenge as big as climate change and reducing carbon emissions to net zero, we tend to focus on how we generate energy - and rightly so - but it's critical that we're also looking at the consumption of energy," said co-author Dr Xavier Moya from Cambridge's Department of Materials Science & Metallurgy.

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Producing Cooling Effect Using Electric Field

• The current study included scientists from Cambridge in collaboration with teams at Japan and Costa Rica
• In the current study, the thermal changes in temperature are voltage driven. Using voltage instead of pressure to drive cooling is easier from an engineering point of view, and allows its application in existing designs, overcoming the need for magnets
• The study team used high-quality layers of PST with metal electrodes sandwiched in between. This enabled the PST to withstand application of higher voltages, with better cooling over a much wider range of temperatures

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Previous Research to Produce Cooling Using Magnetic Fields

• In fact, earlier research teams have been trying to improve cooling technology by replacing the current toxic gases with solid magnetic materials, such as gadolinium.
• However, they observed that the performance of prototype devices was not as good as expected, since changes in temperatures are driven by permanent magnets with limited magnetic fields.

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Future Plans

• In future research, the team plan to employ high-resolution microscopy to examine the PST microstructure, and determine if it can be optimized further to make it withstand higher voltages
• The same Cambridge-led team in a study published earlier this year, identified a cheap, widely available solid material that could replace conventional coolants when put under pressure. Developing this material for cooling purposes needs a lot of redesigning, which is also being actively pursued by the Cambridge team

In summary, the identification of a new cooling to replace existing coolant gases that are toxic greenhouse gases could be good news for the environment with regards to reducing the risk of global warming and climate change.

Reference:

1. Large electrocaloric effects in oxide multilayer capacitors over a wide temperature range - (https://doi.org/10.1038/s41586-019-1634-0)

Source-Medindia