3 ms·

The real issue is the excess heat from losses (breaking, mechanical etc.) [1]. This heats the stone of the tunnels since the tube was built. The heat can't dis

The real issue is the excess heat from losses (breaking, mechanical etc.) [1]. This heats the stone of the tunnels since the tube was built. The heat can't dissipate fast enough. The tunnels get hotter every year. Because of this the tube has gone from a cool place you escape to in summer, in the early 19th century, to a place you'd look for warmth in winter. And a sauna in summer. Any air-conditioning system that produces excess heat as a side effect will make this worse. Even if the passengers on those trains will feel it less. [1] https://www.wikipedia.org/wiki/London_Underground_cooling https://www.wikipedia.org/wiki/London_Underground_cooling

kwhitefoot 3y ago
Can't this be regarded as an opportunity instead of a problem? Sink a few shafts and use heat pumps to extract the heat to a district heating system.
- SideburnsOfDoom 3y ago
  If it was logistically easy to sink air shafts, it would have been done a long time ago, just to vent hot air, long before also using that heat was an idea. It's a densely built up area. Space above and below ground is hard to find.
maherbeg 3y ago
I wonder if they could bore some geothermal loops to move the heat someplace else to dissipate more easily.
- eesmith 3y ago
  Being done. https://www.ianvisits.co.uk/articles/cooling-the-tube-engineering-heat-out-of-the-underground-20873/ https://www.ianvisits.co.uk/articles/cooling-the-tube-engine... (from 2017, 59 HN comments from 2022 at https://news.ycombinator.com/item?id=31694445 https://news.ycombinator.com/item?id=31694445) says > Elsewhere, they’ve been using cool groundwater to cool some of the stations. An experiment at Victoria station was the first, as water from the River Tyburn was used to cool the air in the station. This was only an experiment, but at Green Park, a permanent version was installed in 2012. > There, five boreholes were drilled deep down into the ground, and here cool water is sucked up to the surface, used to cool a separate water supply which is pumped down to cool the platforms, and the warmed groundwater is also pumped back into the ground.
rtkwe 3y ago
They took some heat sources away by switching to regenerative braking and moving to LED lights so the AC has some head room to play with for not introducing more heat. These trains are supposed to run cooler overall than the ones they're replacing taken as a whole including the new AC.

kwhitefoot 3y ago

Can't this be regarded as an opportunity instead of a problem? Sink a few shafts and use heat pumps to extract the heat to a district heating system.

SideburnsOfDoom 3y ago
If it was logistically easy to sink air shafts, it would have been done a long time ago, just to vent hot air, long before also using that heat was an idea. It's a densely built up area. Space above and below ground is hard to find.

maherbeg 3y ago

I wonder if they could bore some geothermal loops to move the heat someplace else to dissipate more easily.

eesmith 3y ago
Being done. https://www.ianvisits.co.uk/articles/cooling-the-tube-engineering-heat-out-of-the-underground-20873/ https://www.ianvisits.co.uk/articles/cooling-the-tube-engine... (from 2017, 59 HN comments from 2022 at https://news.ycombinator.com/item?id=31694445 https://news.ycombinator.com/item?id=31694445) says > Elsewhere, they’ve been using cool groundwater to cool some of the stations. An experiment at Victoria station was the first, as water from the River Tyburn was used to cool the air in the station. This was only an experiment, but at Green Park, a permanent version was installed in 2012. > There, five boreholes were drilled deep down into the ground, and here cool water is sucked up to the surface, used to cool a separate water supply which is pumped down to cool the platforms, and the warmed groundwater is also pumped back into the ground.

rtkwe 3y ago

They took some heat sources away by switching to regenerative braking and moving to LED lights so the AC has some head room to play with for not introducing more heat. These trains are supposed to run cooler overall than the ones they're replacing taken as a whole including the new AC.