Technology.am (Aug. 29, 2009) — German scientists have developed a high-tech mug to keep coffee at the perfect temperature. They used a phase change material (PCM), a wax-like substance to keep drinks cold or hot for longer period.
Klaus Sedlbauer, the head of the Fraunhofer Institute for Building Physics, and his colleague Herbert Sinnesbichler created the first PCM mug using a porcelain shell whose hollow interior is filled with a honeycomb structure made of ribbons of highly conductive material, such as aluminum.
This honeycomb structure is then filled with PCM, if you are drinking hot coffee in one of these cups, the drink’s heat is directed straight into the still solid PCM. This heat, in term, melts the PCM and turns it into a liquid.
Once the material has become liquid, it retains thermal energy, but without absorbing any more heat. The temperature at which it becomes liquid depends on the specific type of PCM, each of which has slightly different chemical properties and melting temperature.
Warm drinks — like coffee or tea — are best enjoyed at 58 degrees Celsius, in order to reach and maintain this temperature; they fill the mug with a type of PCM that becomes a liquid at exactly 58 degrees Celsius. The optimal temperature can be maintained for 20-30 minutes.
PCM cups or mugs could be used to keep perishable foods from spoiling for longer or prevent sensitive machine components from overheating.
PCM cups or mugs can also regulated cold drinks or ice can. Beer tastes best at 7 degrees Celsius, and ice is best at -12 degrees Celsius.
PCM materials can also be used to blanketing the interior walls of museums with the non-flammable material in order to protect paintings from heat damage in case of a fire.
Researchers at the Bavarian Center for Applied Energy Research in Garching think that the fact that PCM is so cheap to produce could make it attractive for numerous additional applications.