Is TfL losing the battle against heat on the Victoria line?

Yikes. I posted this, and I missed that, something I realised soon into my first year physics degree lab. I learnt more than just dipping calculators in liquid nitrogen for fun.

I apologise.

Feynman was complaining about this error appearing in textbooks back in the sixties[0].

The trouble (of course) is that Celsius properly is not a proper unit, but a "scale", or a "unit of difference" (equal to kelvin), or even torsor[1].

The trouble with the kelvin here is that if you see the 7 kelvin increase as a proportion of the 295K starting temperature the you only get a 2% increase. Nobody is going to buy your newspaper if you're putting up weak numbers like that.

[0] https://mathematicalcrap.com/2024/03/05/the-feynman-story/ [1] https://math.ucr.edu/home/baez/torsors.html

And they manage to make it even more crazy by also comparing it to average external temperatures.

== The Victoria Line average temperature in August last year was 60% higher in temperature than the average external temperature that month, measured at 19.5 degrees. ==

Certainly for January it must have been hundreds of percent higher.

And what would the numbers be for e.g., the Moscow metro in winter months where the average outside temperature is negative?

It would definitely be crazy in Fahrenheit, but in centigrade I think it makes some sort of intuitive (if not scientific) sense. (Together with the sea-level assumption we always make in casual temperature discussion anyway.)

Is it? I think it puts the Victoria rise in perspective to the other lines quite effectively.

Everyone knows where the zero is in Celsius using countries anyway and days in the negative are so rare in the UK you can discount them (plus they are none inside the tube).

I don’t know if I’m worried about it. While the measurement makes little scientific sense it makes intuitive sense, and, importantly, the intuitive implications are the scientific implications.

It’s a huge increase, if not for the reasons they describe.

I logged in just to give this an upvote :-)

A problem is the clay surrounding the tunnels insulates them - it traps heat because heat flows through it very slowly. So you drill down and put a heat exchanger pipe down there, you pump heat from 3cm of clay around the pipe and now no heat flows through the clay to your pipe even though there’s a lot of heat still down there.

Your pipe becomes a tiny worm of cold pipe in a big lump of hot clay and you’ve done very little to cool the underground or warm your water. That is, if heat moved easily through the stuff then the problem of heat buildup would be easy to solve but in that case heat wouldn't build up so there wouldn't be a problem; and vice-versa.

The problem isn’t so much finding uses for the heat, it’s getting the heat out of the tunnels to begin with.

These are some of the deepest tunnels going under some of the most built up parts of the UK.

There is at least one on this line (north of Kings Cross) and one on the Northern line (north of Moorgate). It's for district heating or electricity generation.

>wouldn't the people living above the tubes be happy to get a heat exchanger (passive) or heat pump (active, but takes more of the heat) that prewarms their hot water supply

Ground source heat pumps are expensive to build, even more so in a dense area like London. So even if everything you said is true, I suspect the juice isn't worth the squeeze.

What do you do in the summer when the homes don’t want the heat?

Your are correct in principal, though implimenting your idea, now, is essentialy impossible as installing the plumbing after the fact might cost more than just starting over with a whole new line, and would in fact make things much worse durring the many years it takes to find out if the added systems even work. Given that there is only clay under London, it is by far better to start over and build a whole new line, and/or go all in on a mega high tech ,high pressure refrigeration systems for the human occupancy areas, and hope that there are no break downs in the "hot zones" orrible mess

AC will only make the problem worse in the long term. Picadilly got AC because it has above-ground sections.

This. Brake friction pumps heat into the ground at a higher rate than it could dissipate away.

You can blame Blair, I think, for the fashion of putting “for” into the names of administrative organisations.

> This article seems in a similar genre to the breathless advice to remain inside in Britain when the outside temperature might get above 27C / 81F, otherwise known as a not-particularly-warm spring day in much of the US in most years.

It’s really not breathless, because high temperatures and how to handle them is completely absent from the cultural baggage. I don’t live in the UK, but in a place which similarly does not have much in the way of high temperatures historically and low AC penetration, and during heat spikes I see a significant fraction of my neighbours with windows wide open at 4PM.

Habituation is also a significant factor. The UK does not get a smooth transition into higher normals, it gets heatwaves.

Surely that says more about how NYC than it does about London?

If I had to suffer overcrowded trains with standing room only, people’s armpits in my face and all, at 40C temperatures everyday in the summer, then I wouldn’t be laughing at London for trying to avoid the same fate. I’d be complaining that my own city isn’t taking their problems seriously enough.

I'm only in London occasionally but I can confirm that some lines are unbearably hot, in the summer I have no idea how people commute in that heat every day. And I'm originally from a much hotter country than the UK.