Cooling the tube – Engineering heat out of the Underground (2017)

Post by Havoc » Fri, Jun 10, 2022, 10:07 PM UTC

cogman10 wrote: post #40

Makes me wonder if we can do something more productive with the heat. They mention energy generation, but what about heat pumps and water heaters for the above ground buildings? Probably cost prohibitive, but wouldn't it be neat if the waste heat from the brakes ended warming a building or hot water heater?

Post by Havoc » Fri, Jun 10, 2022, 10:10 PM UTC

mountain_peak wrote: post #34

interestica wrote: post #19

I think the Montreal metro faces a lot of these same issues. It works out in the winter where you don't need to actively heat the space. In the summer, it can be unbearable. I'm not sure if the type of rolling stock (rubber tires + tunnel track) has a major difference from other typical subway cars.

I personally don't find Toronto or Montreal subways unbearable (warm, but not crazy), while my time in the London Underground was absolutely miserable - I'm not sure how locals handle that kind of stifling heat. Actually, there was one time I was in the old Toronto Osgoode (pre-opera house) station with a -30 degree wind blowing through - that was chilly! Actually, I'm kind of sad that Montreal has so few cars left t…

Post by andbberger » Fri, Jun 10, 2022, 10:13 PM UTC

fredley wrote: post #17

aaaaaaaaaaab wrote: post #4

Regenerative braking would improve a lot with not just the heat issue, but also air quality. Commuters on the London Underground get a characteristic grey/black snot from the brake dust they inhale. If you stare into the tunnel after a train left you can literally see a haze of brake dust in the air.

It's already got a primitive version of regenerative braking! The deep-line tubes—those that have the heating problem—are designed so that the stations are at peaks in the line. As the train is approaching the platform the uphill slope helps it decelerate, and the downhill helps it accellerate again.

Post by na85 » Fri, Jun 10, 2022, 10:49 PM UTC

Havoc wrote: post #42

SoftTalker wrote: post #38

Earlier quoted context omitted.

I wondered about that. I know a few people with GT systems and it has never been an issue, perhaps because we have real summer and winter here, so the heat dumped underground in the summer would be offset by the heat extracted in the winter?

You know people that have a personal geothermal system?

Post by jamincan » Fri, Jun 10, 2022, 10:59 PM UTC

dtgriscom wrote: post #36

jamincan wrote: post #15

Earlier quoted context omitted.

Regenerative braking generates electricity and there's really no reason modern trains wouldn't use them. Another approach that can be used when initially building the system is to have a slope leading into/out of stations so that energy can be stored as gravitional potential. I know the Montreal Metro was built this way.

Your second point was stated exactly in the parent of your parent comment.