TOM SCOTT: The Youth Winter Olympic Games
have brought me out to Lillehammer, in Norway, and to this:
the Hunderfossen Bobsleigh Track,
the second largest freezer in Norway.
I know, you see "Norway" and "freezer",
and you think about the seed vault that's up in the Arctic
which is technically bigger than this
but this track really is one giant freezer.
This track stays frozen in temperatures up to 20°C
so athletes can speed down here
and pull 4G on the final turn
even when there really shouldn't be any ice for them to slide on.
JAN ODDVAR TANGEN: We can keep it frozen
during the summer -- in a normal Norwegian summer!
It's built with concrete. Inside the concrete,
there are lots of layers with pipes.
Inside the pipes, it's running with ammonia.
TS: When a liquid evaporates, it pulls in heat from the surrounding area.
So there are 90 tonnes of ammonia circulating in pipes
inside this freezer, underneath the track,
being repeatedly compressed and then evaporated
to move heat away. Ammonia, by the way,
really dangerous if it's not handled properly.
JOT: Because ammonia is the fastest working fluid to drag away the warmth.
All the ammonia is going inside 65km of pipes
and it will stay inside the pipes in all conditions.
If something happens, I will shut down the spots
that accidentally have the leaks.
It's lighter than air, so it will be going upwards
so you won't be harmed!
TS: But the laws of thermodynamics always hold true.
You can't create cold. You can only ever move heat.
And in the process of moving it, you generate more heat.
That's why the back of your fridge at home is warm,
and why air conditioning units need to vent outside.
And on a freezer this big? That's quite a lot of heat to move.
JOT: The first thing we're doing is cleaning the track
with normal hoses with water, cleaning from the summer.
And then, start of the season, we're running with luge the first week,
and then we start with the skeleton bob after approximately 10 days
because then the ice thickness is thick enough
to cope with the bob and skeleton.
TS: And with bobsleigh and luge runs being measured
in hundredths of a second,
keeping the ice consistently frozen
is important for what is called "competitive parity":
basically, making sure everyone has a fair shot.
A little bit more or less friction over a day could change the result.
And when there's this much riding on how fast someone goes down a track?
Turns out having a big freezer is really important.
There's a load more videos over on the Olympics channel
and on my channel, go check 'em out, go subscribe,
and thank you to the Youth Winter Olympic Games
for bringing me out here to Lillehammer.
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