OT: Liquid air power storage

The liquefaction process gives off heat, and I assume they store some of that to make the gasification process more efficient?

This is only a pilot plant, so I suppose we'll have to see how it works out. I'm sure they have done all the sums.

At the end of the day, it doesn't need to be efficient. It is utilising essentially free surplus wind energy. Or, if you prefer to look at it differently, surplus from nuclear.

Meanwhile on the DT, the commentators are getting angry in the atrticle about the hinted break-up of National Grid :-

Phil Collins

@George Herraghty @Phil Collins Batteries, nuclear, (some) gas, solar, biomass, hydro, French and Dutch nuclear.

I can?t see any indication of a breath of wind as I look out to sea right now, yet gridwatch tells me 16% of our electricity is coming from wind.

Andrew

You mean like hot based power stations most have lots of cool input, needed to create a temperature differential.

AIUI there is a lot of available "stuff" at ambient temperature (~10 Celsius).

Not so easy without a large and well designed "collector". Air source heat pump external heat exchangers will "frost up" in humid conditions requiring a bit of reverse cycle.

That worried me too. Harrabin is not too bad, but he's not that good either.

Not if the ambient temperature is warm enough. In freezing fog maybe.

It's not a heat pump. It is just using ambient temperature to provide the heat to warm the liquid air.

They are just dumping cold in the same way normal power stations dump heat.

I would guess pumping water over a heat exchanger would do the trick.

Wasn't there a similar pilot done on the old Didcot site?

Probably. People keep truing to square the circle, not understanding that the reason it keeps failing is that it can't be done...

There's rather a lot of peer-reviewed academic papers which suggest this is not "cold fusion" revisited - bearing in mind the plant uses both "waste heat" and "waste cold". Whether the figures can be delivered at scale is of course a separate question which the next implementation will test.

What do you mean by ambient temperature? Yes, you might put the tubes in a vacuum and let the sky and the land radiate to them, but more likely you are using a fluid. Either air, in which case any surface carrying liquid air will suck all the water out and deposit it as frost. Or water, in which case this will collect a layer of ice unless you have a huge area, or are pushing a lot of water rapidly past it.

And have you seen the size of structures needed to do that?

Don't think anyone would confuse this with cold fusion magic.

It probably fits better next to a "nuke" (as a source of waste heat) than most other things. After all it is relatively easy to turn off a fossil fuel plant (and save fuel) when you have excess generation. I suppose you could bury the HX pipes in the sand around a solar plant in the desert somewhere. There is still the issue of what to do with the surplus heat in the compression part of the cycle.

Use it to heat water which is later used to gasify the liquid air.

Or better still, that sodium acetate mix that gives up its latent heat of crystallisation when you trigger it. Then you don?t have to worry about heat loss whilst it?s being stored. You might need rather a lot of it though... ;-)

Tim

Good idea!

Some power stations use heat exchangers using river or sea water.

I could not recall a more recent example of a claim related to energy generation which violated the generally accepted "laws" of physics (c.f. the OP's "This project seems to require one or more laws of thermodynamics to be revoked!").

No such thing as "cold". There's only an absence of heat. To boil off the liquid air requires an input of heat, which has to flow from somewhere. So your boil-off rate is limited by the rate at which you can supply heat. Try to get it too quickly and you just freeze the system you have to transport the heat.

Everything contains heat, even the liquid air.

You radiate it away, like spacecraft do in the outer reaches of the Solar System. These are typically craft which are powered by plutonium oxide (Pu-238), and if they don't need the power at that particular moment, it has to be gotten rid of.