Engineer Designs Mug to Keep Coffee Temperature Just Right
A material (possibly paraffin) that melts/solidifies at the right temperature, so the liquid stays warm for an extended period of time. Reminiscent of Coffee Joulies. Which don’t seem to work as well as advertised, especially in an open ceramic mug. A test with lids in place shows better performance. This mug has a vacuum insulation layer and a lid, but caveat emptor. Though the physics behind the concept is sound.
The concept of a “phase-change” coffee mug to keep beverages warm was patented in the 1960s, but never made it to the marketplace due to manufacturing difficulties. But Maxwell happened to meet an engineer named Dean Verhoeven who had already solved the manufacturing problem. Dean and Maxwell teamed up and Joeveo was born
Their kickstarter closes on Jan 1, with delivery slated for next summer, so not a last-minute gift idea for this year, but perhaps an early shopping idea for next, even if delivery gets delayed a little.
Paraffin wax, commercial “mid-melting” is 135°F to 145°F, /_H(fusion) ~50 cal/g
Polyethyleneglycol (Carboxwax) 4600, mp = 54 – 60°C, /_H(fusion) ~0.5 cal/g
Paraffin solid density is ~0.9 g.cm^3 and molten is ~0.8 g/cm^3 or less. The large enthalpy of fusion includes dense crystal packing. A container without headspace will burst on melting. With headspace, solidification pulls a vacuum, offering atmospheric crushing.
Haga…I actually thought of this idea independently a couple of years ago, but when I googled, I learned it was already done.
http://phys.org/news170425949.html
I guess that one never successfully made it to market. I wonder if crowdfunding is what it needs to give the idea some momentum.