OT: hydrogen economy

[The Natural Philosopher]

I thing gravity is how it got it in the first place,along with nuclear decay - heavy elements ends up in the middle - but gravity doesn't expand and contract

[Tim Streater]

Which reservoir would that be, then?

[Tim Streater]

Caused by what?

[Jethro_uk]

Build them. If we'd decided to do that 30 years ago, instead of waiting for the magic battery to appear, who knows how many we could have in place to be able to harness some of those useless windmills.

I'll caveat this with the obvious that I am not a reservoir expert :)

[Jethro_uk]

[Jethro_uk]

[Chris Hogg]

They say that "The most popular model of radioactive heating is based on the Bulk Silicate Earth (BSE) model (McDonough and Sun 1995), which assumes that radioactive materials, such as uranium and thorium, are found in the Earth?s lithosphere and mantle but not in its iron core". Is that a valid assumption? Bearing in mind that the earth's core, mostly iron in some form (liquid or solid) got there because iron is dense and it 'sank', and that thorium and especially uranium are significantly more dense, I would have thought they'd have 'sunk' too, even more so. So to calculate the heating effect of radioactive materials within the earth based on the concentration of those elements within the mantle and crust, must surely be questionable.

That's not to deny that subjecting the earth to gravitational stresses as it orbits the sun may produce some heating, viz. the tidal heating of the moons of Jupiter.

[The Natural Philosopher]

Where?

If we'd decided to do that 30 years ago, instead of waiting

We did build them 30 years ago. All the good sites are gone.

The cost of Dinorwig, which can give us a gigawatt for a couple of hours was about half the cost of a nuclear power station, that can give us a gigawatt continuously.And that was only because there was a suitable mountain there already.

more storage is just throwing good money after bad

[Chris Hogg]

Amen to that! :-)

[Max Demian]

I think your "sums" are a bit wrong.

A heat pump may be very efficient in the summer, but you don't want heating then.

I don't see how you can get more energy out of gas by converting it into electricity and then back into heat than burning it directly, unless your heat pump is conveniently next to a volcano or other load of hot rocks.

[Andy Burns]

And in cost terms, our domestic electricity price is one of the highest in europe, while our gas price is one of the cheapest, so it doesn't make heat pumps look as attractive as in Finland or Sweden ...

[newshound]

I havn't looked at the sums, but wasn't it Lord Thompson at the end of the 19th century who did a heat loss calc and reckoned the age of the earth couldn't be more than about 5 million years, otherwise the core would have solidified by now.

I suppose the earth gets extra gravitational stresses compared to Venus or Mars because of the moon.

[Tim Streater]

That's because no one knew about heat generated by radioactive decay, at that stage.

Yes. We're quite lucky having the Moon. It stabilises our spin axis, its creation (thought to be the early Earth being hit by a Mars-sized object), gave us a lot larger iron-core and radioactive material, also the Earth's thin crust, and plate tectonics. Having oceans and plate tectonics allows for carbon recycling in the subduction zones. Venus's atmosphere has a pressure of about 90 bar at ground level, most of it CO2, and so a surface temp of 500C or so.

It seems that if you do the sums, Earth's volcanoes have also outgassed about

90 bars' worth of CO2, only in our case almost all of it has been converted to carbonate by plankton etc and subducted back into the mantle.

[Jethro_uk]

It becomes tiresome after a while to keep pointing out to the hairshirt greenies that even if we could reduce our CO2 output by several orders of magnitude, it could be all for nowt when the next big volcano blows (and Vesuvius is due any century now ?).

It's not a reason for doing nothing. But it puts the whole thing into perspective.

[The Natural Philosopher]

Where then?

That is why I have a degree in engineering, and you cant do physics

>

[Andy Burns]

because you're not *just* converting the chemical energy in the gas to heat, you're pulling in extra heat from underground.

Doesn't need that much heat, remember even if the ground is 5C below freezing, that's still +268K

[newshound]

How big does your HX need to be in that case though? And don't you get a better performance coefficient with a hotter source (depends on your working fluid too of course).

[The Natural Philosopher]

..or the air..

tell him how a gas powered freezer works...

[The Natural Philosopher]

You do.

that's why sub zero you probably only get twice as ,much heat out of your pump as electricity in. when its in the low teens you cam get 4x or more #