Prison engineering, greener way to boil water
 

This has got to be a more efficient method that a standard electric range:
https://m.youtube.com/watch?v=ah9dhq_Itzo

I have already used a commercially-available stinger at home. Some people in my homeland use it even to pre-heat the cooling fluid of old cars in the winter :D

Available on eBay right now... many versions and power ratings...

https://ecomodder.com/forum/attachme...1&d=1589140393

And different degrees of safety too.