A Dutch cafe, Natuurcafé La Port, has installed a revolving door that is not only heat-efficient but also generates power as you walk through it. It will generate approximately enough energy to power one house. It’s not a ton, but it’s something!
Via GIZMODO.
OMG thats my idea, i alway hate it when its winter and people leave a cafe door open and you get a cold chill sitting down, damn! hahaha good work!