4 ms·
I wonder, are we now at equilibrium with the surrounding earth so the heat of the trains is now actually vented outside, or is the clay still absorbing heat? I
by Nextgrid 3y ago
I wonder, are we now at equilibrium with the surrounding earth so the heat of the trains is now actually vented outside, or is the clay still absorbing heat?
If it's the latter than this merely kicks the can down the road and ambient temperatures will keep rising.
- mannykannot 3y agoThe article is not quite explicit about that, but it does say "cooler running trains could help to cool the tunnels, but it would take decades to notice the difference, or they can use that temperature gap between the new and old trains to put air conditioning inside the carriages today... If a future plan to run even more trains through the tunnels goes ahead, that will require increased cooling in the stations, which, funding permitting, is being developed at the moment." The implication seems to be that an equilibrium (or something very close to it) has been reached for the current traffic volume (and putting aside climate change, presumably.)
- bluGill 3y agoThe earth is naturally at equilibrium with the average air temperature outside. (when you get really deep the earth's core makes a difference, but at these depths we can ignore that). However when you add heat like the tube does, the earth is enough insulation that it can be decades before it reaches equilibrium again. For purposes of this discussion clay should be seen only for the R-value. (absorbing heat is a very useful property of clay for other purposes, but in this discussion that is not relevant)