London Underground is looking for ideas to make use of the heat in its tube tunnels. There are a number of methods being used to help reduce the heat in the tunnels, but one of the issues or opportunities is to look for a use for the heat that is removed rather than just dumping it into the atmosphere.
The recent connecting of the Bunhill district heating network to a heat extractor inside a tube ventilation shaft has renewed interest in the idea of making use of the heat in the tube tunnels.
Concept schematic
In an “Early Market Engagement” notice, TfL said that it “seeks to inform the market of potential future opportunities to utilise waste heat from ventilation shafts which extract air from the London Underground deep tube network. TfL expects to publish a Market Sounding Questionnaire later in the year to invite feedback from the market to better understand the appetite for potential schemes among potential off-takers, as well as perceived risks and opportunities.”
This is not just an environmental way of reusing heat that would otherwise go to waste, but also potentially a revenue source for TfL. This is also part of the wider cooling the tube project which looks at a range of ideas to reduce the heat in the London Underground.
The lockdown of society may offer a modest respite from the heat for those who do travel at the moment, as there’s been a reduction in the number of trains in service, and it’s the trains that produce most of the heat in the tunnels. The fewer passengers in the trains make a negligible difference, but with less crowding, there’s more ventilation within the carriages, so they feel cooler.
I wonder if the heat build-up in the tunnels has abated over recent weeks with the greatly reduced service?
Yes it has and its lovely! So much more comfortable and you don’t arrive at work feeling like you need another shower!!
Are there any studies to date on the effect of the schemes that have been implemented on temperatures? I know it is early days but has Bunhill Energy Centre been effective in reducing the feel of the temperature to tube users?
That’s not its purpose – the heat was already being extracted from the tube tunnels, and what Bunhill does is then make use of the heat that was otherwise vented into the air and wasted.
I remember Ken Livingstone initiating a scheme for ideas to cool the tube system so that must have been prior to 2008. Twelve years later and still no real solutions. Has our famed engineering genius deserted us?
There’s been a project to cool the tube for several decades, and all Ken Livingstone did was offer a prize for a public idea that worked better than anything LU had managed to come up with (no one won) – and as you would expect with a heterogeneous network such as LU, there are loads of different methods used in different locations — and many are in use right now and have been for many years.
It is possible to convert low grade heat – that’s normally wasted – into electricity. I wouldn’t imagine that the process is hugely efficient but it would certainly be more convenient than trying to balance demand with a heating requirement above ground.
Presumably (?) there is a large seasonal variation in the temperature within the underground and that will coincide with the heating demand above ground.
Can anybody tell me why in the London Underground it is always warmer underground whereas in some other systems such as Prague which is also a deep tunnel system it is always cooler?
i suspect London Underground runs a more frequent service than somewhere like Prague – so more heat generation.
i think the heat builds up in the ground over years and years – and London Underground has been operating for a long time !