The central line can get quite toasty in the summer, especially at peak travel times. I'd be interested in an estimate of how much of that heat is a direct result of the current friction braking system. Will the stations get noticeably cooler if induction braking is adopted? "Enough [electricity] to power more than 100 homes for a year" coming out of a single station over just five days sounds like a ton of energy, all of which is currently being dissipated as heat.
I've always wondered if there was some way to allow buildings to prewarm water for boilers using subway heat.
It'd be an interesting experience without all the extra heat, especially in the winter. (Now we just need to go full circle and use that saved electric to heat the station :-p)
> Additionally, regenerative braking doesn’t produce the heat that conventional friction braking does, so the tunnels themselves stay cooler, requiring less energy expenditure on climate control (and keeping Tube riders happier in the process).
That statement in the article didn't make any sense to me. By my understanding it's a violation of the second law of thermodynamics. You can't take a process that creates waste heat and convert that into energy with less entropy, electricity in this case, and have less total resultant waste heat. Any physicists care to chime in?
Sure you can. As long as overall entropy increases, you're AOK.
Imagine a thought experiment not too dissimilar. You have a bike, that you pedal up to speed. You then let yourself slow to a stop naturally. All the energy you put in goes to heat.
Then you do the same again, pedal the bike up to speed, but this time you click a dynamo (attached to a battery) into place and let yourself stop naturally. This time some of the energy is converted to heat, and some into energy in the battery.
It the same principle of hydro electric power. You can let water just move down some tunnels from high to low gravitational potential energy (GPE -> water velocity), or you can put some turbines in the way.
First, note that the Underground already uses regenerative braking. This article is about a new generation of braking technology.
The Gizmodo article at http://gizmodo.com/london-underground-is-trialling-regenerat... is better than this BBC article. (And the similarities help show which parts come from the press announcement.) It also mentions a £6m/$9m per anum power savings across the entire system.
