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Will the Tube be cooler when all this is over?
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HSTEd
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The deep tunnels are buried sufficiently far below ground level that the rock temperature is essentially constant. Seasonal variations become negligible.
We then dump huge amounts of heat energy into the tunnel that cause the temperature in the tunnel to be higher than the surrounding rock - over years and decades this slowly heats the surrounding rock.
I don't think a few months of reduced input will do very much unfortunately.
Certainly not without taking measures to take advantage of the de-facto closure such as deploying chillers in stations.
We then dump huge amounts of heat energy into the tunnel that cause the temperature in the tunnel to be higher than the surrounding rock - over years and decades this slowly heats the surrounding rock.
I don't think a few months of reduced input will do very much unfortunately.
Certainly not without taking measures to take advantage of the de-facto closure such as deploying chillers in stations.
Thanks guys. I was under the impression that body heat from passengers was part of the problem as well as just brake heat.
Utterly trivial compared with the other aspects of this of course but it will be interesting to see if this makes even a slight difference to tube temperatures- enough to measure if not to feel.
Utterly trivial compared with the other aspects of this of course but it will be interesting to see if this makes even a slight difference to tube temperatures- enough to measure if not to feel.
ChiefPlanner
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The Bakerloo can be a killer in the hot weather , the Central awful. Lovely in winter though.
Some seasoned LT sage told me that the clay surrounding the B/loo was probably baked to terracotta standards by now . I can believe him.
Some seasoned LT sage told me that the clay surrounding the B/loo was probably baked to terracotta standards by now . I can believe him.
A human body dissipate around 100W of heat. Thus a packed train might have 1000 pasengers on board and (say) there is a headway of 2 minutes with an average passing time of 20 seconds. That's equivalent to a continuous dissipation of 100kW x 120/20 ~= 17kW. Now compare that with the power drawn by the traction system, maybe a maximum of 30% of the time in Central London with a thermal efficiency of 70%. As a guess, the installed power in '92 stock is around 1.0 MW so the heat contribution of the trains electric would be 1000kW x0.3x0.3 #= when running in central London sections which is about 90kW over the whole journey. So the human contribution of a crush loaded train would be around 20% of the train's power load. That figure would be valid for less than about 15% of all time. A lower figure would be in quieter times.
There have been plans for quite some time to design, build, and use such a train (the job is currently done manually, which stretches how effective it can be). Unfortunately nothing has yet materialised.
NORMAN471
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On Wednesday 25 March The One Show had a short film about City Road Tube Station on the Northern line. (10.13 minutes into the programme) It showed how tfl were harnessing the heat from the underground to power properties including a school. It may be of interest.
ChiefPlanner
Established Member
I think they had one - (but it may have caught fire ......) - the Paris Metro certainly has one.
Clearly the values isn't exactly the same for all persons, but I've been aware of a nominal value of 300-350BTUs/hr from decades ago. 341BTUs/hr = 100W. It's true that an extreme athlete/cyclist can generate as much as 400W for short periods, but that isn't relevant here, - unless they are having to push the train along.
https://uk.ramboll.com/projects/ruk/heating-up-london
Ramboll was commissioned by Islington Council in London to design and deliver a district-wide heating network to provide cheaper and greener heat to 1,350 homes plus community buildings in north London, using unwanted heat from the London Underground.
Lots of information and diagrams of what is being built on City Road.
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