[OT] Ice rink energy consumption

[Vortex]

Hi,

There's been a lot in the news recently regarding the opening of seasonal outdoor ice rinks all over the UK. These things must be horribly energy inefficient.

I think it's a particular paradox that the Natural History Museum has one....at a time when the Governments climate change targets are such big news.

Does anybody have any idea what the energy consumption of an outdoor ice rink is?

[I guess it would be measured in kWh/sq.metre with some factor for ambient temperature above 0C].

OT and nerdy, I know.....

David

[Ian Stirling]

It's not nearly as bad as you might think. They get a fair amount of insulation (in low winds) from the cold air pooling on the ice.

[Vortex]

I found a fantastic manual in case you want to build your own Olympic size rink:

implies minimum 500 MWh per year just for electricity to support in indoor 30m x 60m sized (full size) ice pad.

D

[Ian Stirling]

1MWh/day , with 1000 customers/day is 'only' 1Kwh per customer, or 10p.

[--s-p-o-n-i-x--]

iirc, something is added to the water that encourages it to freeze at a higher temperature than normal.

sponix

[Ian Stirling]

Heavy water freezes at 3.81c.

[Mark]

Indeed, but at UKP 1500 per litre of heavy water, I suspect most people would choose to pay for the electricity instead.

[Owain]

Still couldn't run it off a 13A extension lead plugged in to the garden shed though, before anybody asks.

Owain

[John Schmitt]

Ice is also a remarkably good thermal insulator in itself, so once the initial energy to freeze the ice (which must be extracted, of course) has been expended maintenence of the situation is not to energy hungry.

While the overall energy may be that large, the financial model is probably pessimistic. The electricity companies give substantial discount to large users. For a start, their loading on the network is more predictable. A large number of small private users is their primary peak-lopping problem. You only need a penalty shoot-out to cause Dinorwig to kick in, because everybody wants to brew a cuppa beforehand. Big consumers work to a schedule.

John Schmitt

[Ian Stirling]

Course it could, you just need a sturdy nail!

[Andy Wade]

But you're only looking at 80-odd amps per phase - it's not a particularly heavy load.

[Martin Bonner]

It's probably even better than that. An ice-rink could stand a five minute power cut every twenty minutes no problem at all. Sufficiently big users can cut deals with the electricity suppliers whereby they cut your supply when they feel like it, in exchange for a reduced rate. It helps lop their peaks.

Mind you, isn't the biggest problem with out-door ice-rinks going to be rain? That's what will really melt the ice.

[sPoNiX]

Or mischievous children with buckets of road-salt?

sponix

[Adrian C]

Why not replace the ice / skate surfaces with PTFE and some PTFE based lubricant?

-- Adrian C

[Dave Liquorice]

Naw all that 'orrible orange gunk. Nice bit of "value" table salt, much cleaner and harder to spot...

[Ian Stirling]

Because ice is not a lubricant. The coefficient of friction of ice on steel is actually (IIRC) about the same as that of steel on rock. What happens at normal temperatures and pressures is that the friction of the skate melts a thin layer of water, and the skate then rides on this. Steel, or whatever on PTFE isn't nearly as good.

However, it's been done - the Roller Disco!

[NikV]

"What happens at normal temperatures and pressures is that the friction of the skate melts a thin layer of water, and the skate then rides on this. "

actually the PRESSURE of the skate on the ice induces localised melting allowing a thin film of water to lubricate the skate, you can see this effect by supporting a mass with thin wire looped over a block of ice. The local melting allows the wire to pass through the block which refreezes (under low temperature conditions) this effect is due to the pressure (ice has a larger volume than the water its made from so that pressure will temporarily liquify it - Le Chateliers principle IIRC)

[John Schmitt]

I've seen it done. No lubricant, just PTFE tiles about 12" square loose laid in a frame. I didn't try it myself, but it looked like hard work compared to real ice. Perhaps the blades were blunt. I'm no expert on skating, I spend quite a bit of the time either in mid-air or horizontal.

John Schmitt