My wife recently got me a new travel coffee mug and it’s the best one I have ever had as far as keeping the coffee really really hot for a long time. It is very thin walled and I just don’t understand how the heat does not transfer to the outside surface of the cup.
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It’s probably a thermos. The mug is made of two layers of aluminum with a gap between them. In high quality thermoses, this gap is vacumed out but either way this gap is extremely difficult for heat to cross. You’ll still get heat loss from the rim and cap but it’s very slow, keeping your coffee hot longer.
If it was just a thin metal wall then the wall would quickly feel hot and the coffee would cool down.
Chances are that’s not the case, based purely on you saying that it works really well. It is probably double walled with either a thin layer of some insulation between the two metal walls, or if the metal is thick enough it could have a vacuum between the walls.
Does it have a Ceramic coating? they are good at stopping heat transfer. I have seen those coatings on racing exhaust pipes.
Does it have a Ceramic coating? they are good at stopping heat transfer. I have seen those coatings on racing exhaust pipes.
That depends on what you mean by thin walled. A soda can usually have less then 0.1mm thick walls. But in order to make the walls rigid and durable you would have to make the walls at least 0.5mm thick. This is the advantage of using metals as you can make very strong thin structures. But most travel mugs are double walled. And if we take two of these 0.5mm thick metal walls and space them 5mm apart we get a total thickness of 6mm. That is about the same thickness as a thin ceramic mug. But there is 5mm of insulation in the form of vacuum or a thin gas.
Vacuum between the inner and outer walls. Meaning, your coffee can’t cool down via conduction(like when you touch something hot) or convection(like when the blow dryer heats up your hair). Only method of heat transfer left is radiation , and your coffee is not the temp of a neutron star, so the coffee’s radiation and therefore it’s overall heat transfer, happen much more slowly. This keep the coffee hot.
Heat transfer is my jam.
That depends on what you mean by thin walled. A soda can usually have less then 0.1mm thick walls. But in order to make the walls rigid and durable you would have to make the walls at least 0.5mm thick. This is the advantage of using metals as you can make very strong thin structures. But most travel mugs are double walled. And if we take two of these 0.5mm thick metal walls and space them 5mm apart we get a total thickness of 6mm. That is about the same thickness as a thin ceramic mug. But there is 5mm of insulation in the form of vacuum or a thin gas.
Vacuum between the inner and outer walls. Meaning, your coffee can’t cool down via conduction(like when you touch something hot) or convection(like when the blow dryer heats up your hair). Only method of heat transfer left is radiation , and your coffee is not the temp of a neutron star, so the coffee’s radiation and therefore it’s overall heat transfer, happen much more slowly. This keep the coffee hot.
Heat transfer is my jam.
Does it have a Ceramic coating? they are good at stopping heat transfer. I have seen those coatings on racing exhaust pipes.
Vacuum between the inner and outer walls. Meaning, your coffee can’t cool down via conduction(like when you touch something hot) or convection(like when the blow dryer heats up your hair). Only method of heat transfer left is radiation , and your coffee is not the temp of a neutron star, so the coffee’s radiation and therefore it’s overall heat transfer, happen much more slowly. This keep the coffee hot.
Heat transfer is my jam.
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