Why It's (Almost) Impossible To Cool The London Underground
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- Опубликовано: 13 сен 2024
- The London Underground is a marvel of British engineering, but right now it’s also really hot. Here is why the tube is experiencing a heatwave, and some ways in which we’re trying to cool it down.
Engineering Europe, Episode Seven | Into the Inferno
#EngineeringEurope #London #UnitedKingdom
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Translations
CZECH: Ondřej Špika & Martin Hofman
GERMAN: Aaron Kerker
INDONESIAN: Anugrah No'inötö Göri
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It’s literally so hot they’re thinking of using it as a fucking geothermal energy source.
adapt, improvise, overcome
>use it for geothermal energy
>power ac units
problem solved
Stonks
@UCH8ykuGprgc1GmeC9YUmT-g be quiet
I heard they are considering atomic fusion since the temperatures are already very close to what is needed for that.
Hey! Really great video, well made and interesting, excellent work.
Hi! Thanks so much! So happy that you took some time to watch it, and pleased that you found it engaging. Hopefully I'll get a chance to visit London again and see some of the cool things you've shared.
Hey Chris, fancy seeing you round here :)
:O hi
Oh hi cris I love ur videos
@@AtomicFrontier this is actually so good, you remind me of the B1M
I didn’t know about the clay gradually holding more and more heat thing, that explains why the heat seems weirdly radiant in the tube!
It's incorrect. Otherwise the tube wouldn't be comfortable in winter. Clay still dissipates the heat. Just much more tube traffic then in the past decades.
@@Dosedmonkey Some lines really aren’t that much better in winter, and it doesn’t make the clay holding heat untrue, it’s just that it’s obviously easier to get the air temps down there slightly lower using the ventilation shafts, when the air outside is freezing cold. Crazy I know. Almost like cold air is easier to push downwards or something. Hmm.
Or I assume that they have a good amount of air circulation from the outside. And if 10° c air is heated to 23°c air its still very comfortable. But if the outside air is 28° the inside will be boiling
idea: install air conditioners in stations and release the hot air outside
I frankly don't buy the "80%" figure, but it's certainly the case that the tunnels would have been cool to start with, would have warmed up as they were used, and will hold onto and radiate heat back into the interior.
The majority of the heat in a space is typically in the material of the construction rather than the air, and this is only going to be exacerbated in a tunnel where the walls are, for all intents and purposes, infinitely thick, and surrounding a comparatively tiny interior. Which should be obvious. An average house weighs in the neighbourhood of 60,000 kg (minus foundation, which might be 1-2x as heavy as the rest of the house. In contrast, the average house contains only about 700 kg of air.
I'm so used to the litany of smaller vents/grates all over NYC that I never considered how important they are to temperature regulation. This was great!
I love those vents! Great for warming yourself during the cold winters. Maybe we could repurpose some of the transit heat into warming stations
For having a seemingly low budget, the content in this video is amazing! Descriptive, yet quick, detailed, yet not boring, and all very clear, yet still concise. Even the graphics were great too! I can't wait to see the content that you will produce as this channel keeps growing!
Low Budget? Look at his wrist.
Mommy and daddy have full pockets
@@maxkraus7063 Because young people can't possibly be economicly succesful right? The fact that you're a useless NEET doesn't mean everyone is.
I thank Tom Scott for getting me here. You make some amazing content that is very interesting. :D
Me too. Well done, young fella. Liked and subscribed.
Same, he deserves the extra attention. Especially from the Audience of Tom which means many will like his content as well.
That's how I found him too 👌 they should do another collaboration
Wow, I didn't expect the simple image of someone sitting on a tube without a mask to look so weird
Filmed before COVID-19 🙂
@@samuelfellows6923 I know
It really does feel weird now.
That is sad :(
@Cian MacGana cool who asked
The Bunhill Energy Centre shown in the video isn't near a tube line, and isn't the one using heat in the manner described. What you're referring to is Bunhill 2, which is a red building on City Road.
I was expecting all those passengers to contribute more of the heat, I was surprised.
...as was i ...perhaps on the carriages, if crammed full it be a different experience
Ask anyone from up north, they'll tell you how cold Londoners are 🤣
Most of the stiffling "heat" you sense in a crowded space is actually water vapour and carbon dioxide triggering your breathing reflex.
Sure, you add a little bit of heat in a small room, but the energy levels needed to push all that air around (the syringe effect) as well as the stop/start corresponds to huge amounts of energy, all of it being dumped as heat.
The heat load of each person is around 200W, made up of sensible heat (dry) and latent heat (vapour).
@@stevieinselby as long as we aren't stingy, nothing else matters :P
The trains *do* use regenerative braking. They put current back into the 4th rail for use for trains.
4th rail? I've only seen a 3rd power rail. Why would you use 4, rather than the 2 used for rolling grounded?
@@RobBCactive LUL uses 4th rail. Two primary rails, a center rail and outer rail that are a positive 420V above earth, and a negative thats 210V below earth.
I guess the reason being was to reduce voltage drop between earth and live.
@@thetrainshop Thanks!! I hadn't ever seen that detail and was thinking of the old rickety 3rd rail in S. England trains which aren't served by overhead supplies.
If that is deployed over most of the tube lines, some major rebutting should be going on, as it's a very common reaction to be surprised by that.
I just remember discussion decades ago why regen was not more widely deployed.
I was legit surprised that Britain's subway cars use friction breaking. Never would I have guessed that an all electric train WOULDN'T use regenerative braking, which automatically removes a massive amount of maintenance cost, but also heat and brake dust that's going to build up. Seems like a no-brainer, but alas, humans be humans.
When they were designed, regenerative braking wasn't really a thing and no-one has thought to change it since
@@icedragon9097 when they were designed? How old do you think those cars are? Disney's monorail trains were built before 1970, and had regenerative braking. Diesel-electric locomotives have regenerative braking, and how long have they been around?
@@ElementofKindness pretty sure the tube is over a hundred years old haha
@@RichardLDN not the trains though!
This video was very poorly researched in many strange ways, you can see some people explaining errors in the comments.
That is pretty amazing that 80 % of all heat ever produced in London's underground is still there. Is that really true? I mean you would think the heat would leave via warm air. Then there is conduction and so on.
Well if that is the case, then that's pretty amazing.
It's all about the clay retainment.
Need to blow more freezing air down there in winter.
"Brakes on a Train" The Hollywood sequel we've all been waiting for.
It boggles the mind that clay is so good at holding on to heat, that you can store it for colder months like it's dried fruit or something!
Funnily enough, built a box out of clay, place fruit and other perishable food inside and seal it up, and that food will be able to stay edible for much longer. Many medieval castles used underground clay pantries to seal up food incase of a siege cutting off access to food supply.
Not only clay. It's a general thing with earth mass. That's why the warmest months are July and August, although the sun is most intense before and after June 21st. The storing of heat causes the delay.
Dig down 6 meters and the ground has the yearly average temp all the time.
@@GrandTheftChris Funny that, I always read that it's the sea that moderates heat, land warming quickly heats air which draws in cooler maritime air.
Hence continental interiors having greater extremes between summer & winter
Hurricane season is later, powered by warm upper layers of water
Yeah, it's incredible, you'd think someone would have thought to line large ovens with clay fire bricks... Ohh, errr
One thing I never understood, the Madrid subway is immaculately cool and all stations & trains are air conditioned. It’s a more modern system to be sure and probably less of the clay issue, but it proves that it certainly is possible to have an air conditioned train system including the stations.
True, many stations in New York have air conditioning, but many also do not. It's annoying, at least the train itself has air conditioning
London tube lines in centre can be deeper tunnels barely larger than the trains lined with ceramic tiles with large distances between stations. Most city metros are shallow cut n cover construction built beneath large roads, with the space for vents and easier access to the surface. Their stations are generally short walks apart like city bus stops.
There's also something dubious about this film, as if the tube were an oven, it'd be uncomfortably hot all year round, not just in summer months. It's mainly a ventilation problem with the air pushed by trains significant.
Just hire Australian train drivers, then they'll complain about the cold
Thank you algorithm 👍🏼
Glad it recommended your video, it was well explained and moderately entertaining.
As a newcomer to London, I already find the Tube in winter horribly hot, and I can only imagine how horrible it must be on summer!
It's not that bad, there is a rush of air and it's not as if people hang around, everyone is in a rush. People just need to make sure they wash and wear deoderant, that's all 🤣
Incredible video. This was so well produced and executed. Kudos
Very well done video, i'd be interested to see more London related content. I came here via your comment on a video called 'Londons empty houses'.
*London's fake houses
Thanks! Will definitely be back soon!
Same here 😄
Hell freezes over ever year- it’s in Norway.
Good vid by the way.
Thanks! And check 4:04 in the video.
You don't store the energy from braking, it just gets put back into the network and is used instantaneously by a train accelerating elsewhere on the network
@@TMinusRecords you could but it would be relatively worse than using it instantly. Storing energy on that scale generates heat, transfering energy produces negotiability amounts of heat
Spinning rotors generating electricity do store energy, that's why when power shortfalls occur you see frequency drops.
There are also back generation effects caused by inductance, which effect large motor systems.
Great video, subscribed
This is so well produced!!!!
I was surprised to see that you only have 40k subs. This is really well made, high quality content. I'll definitely be sticking around
“They say that hell will freeze over before you can find a seat at rush hour.”
Me: looks at date posted
Oh you sweet summer child
Great channel by the way! Keep up the amazing work!!
69th like
I have a bag around my waist which makes me look pregnant. That way I get a seat at rush hour!
Don’t get it
@@asherjackson4504 Video is from 2019. 2020, Corona.
@@asherjackson4504 During the 1st lockdown trains were empty. 2nd lockdown they were sparse. 3rd lockdown you can easily get a seat but there's still too many people coughing on the lines
Melbourne's city loop tunnels don't have this issue, despite having compressor air conditioned trains with disc and pad brakes, as the tunnels are short enough that the piston effect keeps outside air coming in, along with a couple strategically placed ventilation shafts. However our new train tunnel currently being built is substantially longer, time will tell if overheating will become an issue, but you'd hope they took some experience from tunnels elsewhere including the London tube and designed accordingly!
How is your production value so good, I feel like I'm watching an old school Discovery Channel documentary
Regarding air conditioning, 1 cubic meter of ice (1 metric ton), can absorb ~97kwh of heat. I wonder if air-conditioning would be viable if it consisted of blocks of ice which would be produced and swapped at the terminal stations. Heat stays out this way, the ice can be produced during off-peak hours, 1 metric ton is around the weight of 11-12 adults which is a tiny addition to a train that can transport hundreds at a time. The ice can be positioned at a central location with fan coils cooling each wagon.
Good to see you back, all of your content is wonderfully informative and well paced, taking on many obscure topics. love it!
Thanks! Its been a hectic semester, but so glad to be back making videos.
RUclips algorithm starting to blow this up. Here's to a million views.
The structure in your videos are brilliant. Keep up the brilliant work. Thanks to Tom Scott for the recommendation!
In Bucharest, the metro system is a fan favourite during summer because it stays way colder than any bus or tram. Imagine my shock when I first used the London Underground
Interesting video! Might be worth mentioning that quite a lot of tube trains already use regenerative braking - the 1995 Northern Line stock and all subsequent fleets (and the 92 stock Central Line trains are currently being modified with new traction motors to enable regen braking)
That reservoir idea is freaking genius! I love it.
Lovely stuff! Very informative and brilliantly delivered. Thank you!
Hi there, just dropped in from recommendations and I have to say I was rather impressed by the cinematography in your video as well as the infographics. The video was informative, concise and entertaining with good introductions to each segment. Good work! You have a new sub!
I always thought they should use a heat exchanger to capture the heat from the tunnels and use it elsewhere. Glad someone is looking at it. Get @LinusTechTips on it to watercool it 😂
High praise for studio voice over. My ears are thankful
The production on this is brilliant. You deserve way more subs
Glad you think so!
Having lived in London I always liked how they were nice and warm in the winter. In the 80s it was kind of pleasant. Dunno about since about 2000.
That's a really well-produced video! Thanks!
You make really cool content and explain things in an easy to understand and engaging way!
Excellent animations
Hahaha that's a classic BBC documentary voice.
Good stuff!
*Sherlock theme plays*
Oh yeh now it’s getting hot in here
I was in NYC and damn this is so hot down there! Here in Nuremberg, Germany we do not only have fully self driving subways but it is also so cool down there in the hot summer. While outsite is 38°C down there it is about 15-20°C which is awesome.
Amusingly, the Montreal Metro has a much cleverer and simpler system for slowing down trains as they reach the station. The stations are elevated higher than the general track, so the train loses speed as it goes up the hill. Then when leaving the station, it goes back down and gains speed. This is far more efficient than basically any other option.
That is ingenious, I had never heard of that but I hope the designer was applauded for it.
@@krashd It's pretty cool system overall, though i imagine the boutique decisions add cost. They use rubber wheels for deceleration and acceleration that make no contact at any other time.
Obviously the "hump system" is nearly impossible to retrofit, but it's cool.
Clever, gravity is an excellent way to store energy. It also means the stations are closer to the surface and thus there is less distance for passengers to travel down.
Awesome vid!
You're doing a great job with these videos. Keep it up, it's very interesting!
great video thanks I could not understand as a Aussie why I was dying in the London Underground and couldn't figure out why they didn't get rid of the heat in it... you have answered all my many years of questions in just 6 minutes lol
Using the waste heat to warm homes makes sense. I'm curious how much electricity can be generated by the facility, though, given that the efficiency of generating electricity from heat differentials depends on the magnitude of the differential
I'm really skeptical the waste heat will be useful. It might be possible to use the heat to warm a few homes but I really don't see a way the heat could be used to generate electricity.
My city has vents that go through the street down to the subway
In Vienna, Austria, we use regenerative braking for decades already.
And:
The trains push the air through the tunnels and hence it gets warmer because of friction.
In order to reduce the amount of air blowing through the stations there are tunnels connecting the two train tunnels through which the air can escape to the other one.
In a few (too little) spots they installed heat exchangers in those connecting tunnels and are heating houses with that excess energy.
Compare the size and age of these transit systems. Some lines have used regenerative braking.
But that narrow tube with a moving wall of air is the ventilation system in tunnels in parts of the network.
New lines cost huge amounts of money and deliver far more benefit, than re-digging extra tunnels that disrupt services a huge city relies on.
Older lines suffer from a lack of will to invest on maintenance.
Honestly i would install radiators, but cycle cool water trough it. Afterwards cycle warmed up water trough thermal exchanger and use heat to either supply homes with free heating during winter, warm water or electricity productions. Waste heat could disposed trough evaporators.
Seoul, Korea seperates the platform from the trains with a wall of automatic doors that open when the train doors open. Would that make any difference?
The London tube will be having platform screen doors soon so mabey that can help
Im pretty sure the canary wharf stations have that
@@nealeellis4455 yeh they do i should have said some stations already have them
Great video, can't wait for new content!
I am quite disappointed....
by that low subscriber number.
This video was really good. Nicely illustrated and easily to be understood even by myself (not a native speaker).
Looking forward to watching all other videos.
Gotta thank someone's comment on @Jagohazzard' s YT channel. Very well informed and presented material. Think you got yrself another sub. Thumbs up!
I think you should so an episode on rollercoasters, mabye how they are operated or how much power they use or something
This is a video that is really well done. I love your research and the graphics. It is informative whilst concise. I look forward to seeing more content.
Thx for keeping videos short enough
Trains already use regenerative braking, but not in the sense you might think. Physical brakes are the last ditch effort in emergency braking while normal braking is done via the same motors that actually power the train turning the motors into generators. This generated energy must be deposited somewhere or the motor wouldn't be able to brake so the train has heating elements that soak up that electricity which are much like sauna stove or swimming pool heaters.
Excellent video! Very relevant and interesting topic with extremely high production value! Incredible talent!
This looks very professional!
Many New York subway stations get hot as well. At least the train itself is cooler on the inside with air conditioning. The heat is terrible though, I wish you's good luck.
NYC is far hotter than London in Summer/Autumn and colder in winter.
It's tunnels are square construction, not narrow lined tube tunnels, which can be much deeper.
A/C would increase overall energy consumption significantly, likely exacerbating the problems of a poorly ventilated tunnel network
_Laughs in ventilated tunnels of Moscow Subway_
I once caught cold in August because I didn't put my jacket when going to work
Except colds are caused by viruses, not low temperatures :)
@@dunebasher1971 But rhinoviruses which cause the common cold love cold temperatures.
Great video ,very informative and interesting also top notch editing
The Geothermal Idea is such a good one. That combined with some of the other ideas presented would definitely do at least something.
The problem is that the air is not warm enough to be true geothermal with decent efficiency. It wont get much above 40 C anyway. Sure, using a heat pump you might be able to create a heating network that uses 50% electricity instead of 90% fuel, but it is still woefully inefficient.
Once they solve that little problem stemming from the laws of physics, I am all ears.
@@57thorns Actually that’s not a problem at all considering that in colder countries such as Norway air-to-air A/C units are used to heat your home even though the outside temperature is as low as -10°C
@@koppadasao Those heat pumps have an energy usage compared to direct heating of between1:2 and 1:3 at those temperatures. Not better than burning things given that they use all electricity.
If you have a hotter temperature like 60-80C you just need to restrict the heat flow with a minimum of electrical input, and those are the operating temperature of district heating, which this might be used for.
The limited air capactity of those chambers, and the limited temperature would make it impossible to use for producing electricity, and the low thermal mass would be used up in no time even if used for direct heating.
You are better off using forced ventilation in the tube itself. This sounds just one more of those magical "energy from nothing" schemes (scam if the people behing it actually know enough to understand that it can't work).
@@57thorns The way to get usable heat energy out of all this would be to have water pipes running in the clay near the tunnels where they'd pick up the heat in the ground around the tunnels. Those pipes would be tied into the heat exchangers. Who knows how many buildings could be heated this way but it would be pretty efficient. Moreover, the overall goal is to lower the temperature in the tunnels (doing something useful with the heat is a side benefit), which this would eventually achieve.
The main issue would be the practicality of laying pipes (you'd use flexible pipe to be sure) in close proximity to existing tunnels, but new tunnels anyway could have them incorporated during construction.
@@davidjames4915 That is definitely an idea I could see working. Heat, but not electricity.
Really good video especially given he seems to have done most of the work himself.
Really great videos!
5:40 They say that hell will freeze over before you find a seat during the rush hour.
well actually
starting and stopping all the time without regenerative breaking?
wasteful!
I was surprised to hear they don't have that yet. Amazing, I'd imagine it would save them so much money in electricity. And the tech exists since decades.
They do, at least on some stock - Northern Line and S-stock, certainly. There are brake gauges in some carriages and you can see that they don't budge until the car is virtually at a standstill.
TfL have a calculation of what regeneration saves both in terms of electricity and 'cost of cooling', can't remember where I saw it.
They’ll probably get round to installing it in 2040...
Also remember they're pushing a huge wall of turbulent air like a plunger in narrow tunnels, that gives an air brake effect. Infra red shots of trains in stations just after braking, will show heat.
If this magical clay oven existed, winter temperatures would be excessive too.
Really it's caused by inadequate ventilation.
Props on the production quality. Keep it up you're going places with this.
Nice work!!
Excellent video.
Brilliantly interesting as ever.
This channel is both very cool and, I should hope, heating up fast!
Well done, James -a really interesting video. A couple of questions: (1) Is the storage of summer warm air to supply the Bunhill Energy Centre during the winter actually in operation now or it an idea that is being considered? and (2) What's the connection between the Perth Rail Heritage Museum and the London Underground? Is it one that I, as a longtime resident of Perth who was born and brought up in London, should be familiar with? Whatever the reason it was great to see the Bassendean Museum in your video.
Wow, great spotting and good questions! (1) At the moment Bunhill is just fed directly from the lines, with the key seasonal change being that it pumps extra air in during the summer. Stage Two of the project (taking place now) plans to increase capacity by a further 1000 homes by using an extra ventilation shaft from the Northern Line, but again this is just direct heating. Tunnel storage has been discussed, but there aren't any plans to implement it just yet. (2) There doesn't appear to be any connection between the Rail Museum and the London Underground (beyond some of the trains being built in the UK). However, since I wasn't able to perform any demonstrations while travelling, and my Australian lab isn't nearly as exciting as the one I used while at Leeds (featured in some of the earlier episodes), I thought the historic trains at the museum provided the perfect backdrop. Had no idea the museum existed before the video, will definitely be back!
Hope that helps! - James
Very nice and informative video, thanks :)
I hadn't realised heat retention was such an issue for the Tube. Thank you for an excellent video. Time to read up on heat exchangers now in use/planned.
They could of course also just cool it with evaporative cooling or some good old pipes with cold water.
The idea of generating electricity from the "only" 40 degree tube air seems very optimistic. And properly will not justify the cost of the generation equipment, over just blowing outside air down with a fan, or fancy convection.
Andreas Fønss Evaporative cooling wouldn't work - it's already quite humid down there and anything that increases humidity makes the problem even worse. There are stations cooled using water passing through large heat exchangers that look like air conditioners - green park I believe is one, I think they use ground water that's then re injected into the ground through boreholes.
Great video!
Atlanta’s deepest station is cut into solid granite. It’s usually cooler than outside in our scorching summers.
Time will tell if that heat dissipates adequately or it becomes like London's tube. Granite is a better heat conductor at 3.2 as compared to clay at 1.7 to 2.26. Sources:
Granite:material-properties.org/granite-density-heat-capacity-thermal-conductivity/
Clay: www.sciencedirect.com/science/article/pii/S0375650520302017
Also Atlanta’s system is air conditioned. London’s isn’t
This video was surprisingly interesting and informative. Glad I've found your channel, you're going places.
Thanks for the video. This is one of the things I noticed about the deep level tube stock while I was travelling around London back in 2014 and 2016. The designers of the newer tube trains still had not considered the AC in mind compared to the MRTs in Singapore which have air conditioning since it began operations in '87.
They need to do a cad on the entire network. Then actively pressure surged controlled and oneway dampers. Bit job
They should do it the way my local subway does it, in the winter all the rails snap because of the cold so they have to shut the subway down so the tracks don't snap, and in the summer they get what they call spaghetti rail, so they have to shut the tracks down so they can cool down.
Good content! Keep up the good work :)
Great video, thanks 😁
This is a really cool video
Normally when the British complain about heat it’s something like 22c or close to it. But for once the British have a right to complain and therefore win this round, 40c(104f) is in fact hot enough for even us Americans to complain.
Good production values. Well done.
Presumably this is why the Victoria line is cooler, because the tracks are shaped to make the train slow naturally as it enters the station.
Sounds like the average summer temp where I am at. Been triple Digits for almost two months. Like imagine it is 100-110 degrees everyday with 80 degree nights. Stays into the 90's even still come mid October. Good times.
Definitely wasn't expecting to see the Western Australian Rail Heritage Museum in Perth appear in this video!
Another great video, James - it makes me nostalgic for the Auld Country! Why is the video from 5'40" a mirror image?
Hi! So happy you keep enjoying them. Its flipped because of the idea that things that travel left to right (how we read) feel more natural, and makes the audience feel like we're moving forward in the plot. I managed to keep that working in all shots except for two, so needed to mirror the image to ensure we kept that flow going throughout.
@@AtomicFrontier You're an absolute genius.
Thank you for asking this! I was wondering too!
A water jacket might do it. You could pump water from the Thames into pipes with relatively high surface-to-liquid volume ratios lining the inside of the tunnels and then pump it right back out to the Thames.
Great video, it really makes ya think.
I never knew I wanted to see a T-Rex with a sword. But now that i did, I love it
another brilliant video!