Many previous efforts have been made to achieve rapid drinks cooling on demand. The problem has always been the time it takes to effectively cool the liquid. If the cooling is very fast then the outer layers of liquid freeze before the inner liquid is cooled. This creates “slushing” which is unacceptable to consumers. The way to avoid slushing is to agitate the liquid, however, when this is done to carbonated drinks it causes ﬁzzing when the drink is opened.
The team found that by rotating the beverage at a certain speed to create a Rankine vortex the carbonated liquid could be mixed without disruption to the bubbles of carbon dioxide. The team also discovered that by simply rotating the beverage the vortex behaved like a solid, with the outer liquid cooling faster than the inner liquid. Tests showed that cooling rates could be improved by collapsing the vortex and then recreating it; this was achieved by a stop start rotational sequence. This pulsed rotation is the essence of the ﬁrst patent ﬁled by Enviro-Cool (UK) Limited.
Further tests revealed that it was possible to interrupt the vortex without stopping the rotation. This was achieved by rotating the beverage around twin axes. Cooling rates improved even further with this method, and a second patent was ﬁled by Enviro-Cool (UK) Limited to cover this process.
Regent and Pera Technology built three prototypes to demonstrate the proof of concept.