posted on April 02, 2014 |
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Maintaining the temperature of a beverage, hot or cold, has been a challenge for years. It has also been addressed by engineers in innumerable iterations of insulated mugs. The problem? The mugs only acts to maintain beverages at their current temperature. They don’t actively control the temperature.
Logan Maxwell, a chemical engineering student at North Carolina State University, wasn’t satisfied with current offerings. As part of a senior project, he and classmates came up with the idea to create a travel mug which would regulate the temperature of hot beverages by cooling them to a safe drinking temperature quickly and also retain that temperature for hours.
The idea was a good one but not a new one. Engineer, Dean Verhoeven, had been working on the concept for about 15 years. He was surprised to find that a group of students was approaching the challenge just as he had. And they happened to be doing so just down the road.
The mug works by phase change. Like many others, the mug uses vacuum insulation. Unlike others, there is another insulative layer that regulates temperature. This “Temperfect” insulation is active.
Above 140 °F, where it can be dangerous to consume liquids, the insulation melts and absorbs the excess heat. This quickly cools the beverage to an enjoyable temperature. Over time, the insulation returns the heat as it converts back to a solid.
Don’t worry, the insulation is separated from the beverage and is reported to be perfectly food safe (a food-grade wax, perhaps?). All of this melting and solidifying is happening behind the scenes, so to speak, and the mug doesn’t appear out of the ordinary.
In a first-order phase transformation, as the material melts, it maintains the melting temperature until completely transformed to liquid (likewise when solidifying). In this scenario, the steady-state temperature of the beverage could be controlled by varying the material, and, therefore, the melting point.
The material must also be able to absorb enough energy to regulate the liquid volume before the phase transition completes. The specific heat (or heat capacity) of the material will determine how much beverage it can regulate. If it absorbs a lot of heat during its phase transition, then it would not require much of this active insulation to regulate a relatively large amount of liquid.
This could have applications in realms outside of beverages as well. For instance, what about a bath tub for infants which keeps the water at a safe temperature longer, or thermal management to mitigate brief spikes in temperature, perhaps in electronics?
The general public backs the idea. The two teamed up and successfully launched a KickStarter campaign which raised $269,271. The company, Joeveo, is now seeking to bring you “beverage bliss.” Certainly a happy ending to a senior project. I’ll drink to that!
Below is a video from the KickStarter Campaign that explains the concept and pairing.
Photos courtesy of Joeveo via KickStarter