ground source heating

[Fredxx]

Do you accept that the deeper you go, it gets hotter? A yes / no answer would be fine.

[dennis]

I have already answered that many times and shown the physics of why. It is not relevant to what TNP said, i.e. it is not why mines are hot and has nothing to do with GSHP or even geothermal power.

[Fredxx]

Once more time wouldn't hurt.

Is the ground hotter at 1 km depth than at the surface? YES/NO?

[The Natural Philosopher]

Thats because you haventt. and you haven't.

That entitrely depends on how deep you go.

No, I pointed out that they were not hot because 'people were working in them'

No, they do not.

Which is hot.

so you agree that the mine needs cooling.

Thats because its normally not worth going a mile down to extract geothermal rather than solar, heat. However. once you have an abandoned mine that deep, you can.

yes. essenitally.

yes, but not to the scale that you suggested. Its not the size of the borehole, at ground level its a complex calculation concerned with the conductivity of the ground. Essentially a sinle borehole will be abstracting energy more or less over a very wide area indeed. Probably at least as wide as it is deep for 90% of its energy, and about 70 % from the first few square meters around it. I have shown that is more than enough incident energy to do that even at high densities of boreholes.

If its used for aircon, they will alse be higher. In late summer/eraly winter.

That's what the ground does, stoopid.

trhats only becaiuse you are thicker than Drivel.

wrong.

? you are talking drivel.

NO one mentioned shared boreholes

Why dont you.

I have.

You cant.

[The Natural Philosopher]

No, you haven;'t. UYou have spouted garbage as if it were real scince.

It has everything to do with geothermal power.

It IS geothermal power.

[Man at B&Q]

Glad to see you've finally grasped that bit.

MBQ

[dennis]

Oh go on then tell me where I am wrong!

8<

The hell you have. Even then your so called argument actually agrees with what I said apart from the area you think is needed.

See you are agreeing again while trying to make out that I haven't already stated that.

Now you are being stupid enough to call me stupid when its obviously you that doesn't understand the basics.

How stupid to state that when it is obviously untrue.

Oh do try and keep up!

So you feel its necessary to snip my argument and counter it with more personal insults. What makes me think that you just don't know anything at all about GSHP.

[dennis]

You are stupid. Men die in mines where its not cooled as all the heat from working has nowhere to go. Rock is a poor conductor so the mines get really hot, its the same in tunnels, they get really hot even though they are horizontal which according to you and TNP would keep them at the same temperature. What else have you failed to grasp?

Try this one..

if it is 5C at the top of a GSHP's borehole what temp will it be at 100 m deep? Explain why?

[Fredxx]

Must be too difficult for Dennis to answer.

[dennis]

I would say the answer is too difficult for you to understand as you obviously haven't.

[Fredxx]

The required answer was yes or no. The question is simple enough, is rock a km down hotter than the surface. What is there to understand?

[dennis]

The physics I stated tells you the answer and also tells you why its irrelevant to the argument. Is that too hard for you to understand? I expect so.

BTW the argument is is a mine hotter or not, not a rock and the answer to that has also been explained but I expect that was too hard for you too.

[Fredxx]

You were trying to argue that a mine is hotter because at some point in its history it had been worked. Others here said it was geothermal heat energy which caused the higher temperature. I simply asked the question "Is the ground hotter at 1 km depth than at the surface? YES/NO?" You claimed you answered it, but now you're wriggling by saying that this question isn't related to the thread.

Once again; Is the ground hotter at 1 km depth than at the surface? YES/NO?

[dennis]

Well OK as you don't understand the physics and can't understand that I have already answered the question I will answer it in a different way that you still won't like..

I offer you the temperature at the bottom of the Antarctic ice sheet which is more than a km vs. the temp at the top of the Antarctic ice sheet. It must be colder at the bottom or the ice would melt under the increased pressure. If heat conducted from the core had any significant effect this could not be true. Of course you can't measure it easily as drilling a hole will increase the temp at the bottom due to the energy needed to drill the hole.

[Fredxx]

Are you trying to being extra stupid or just plain ignorant, didn't you know there were lakes under the Antartic ice sheet?

I quote "The average water temperature is around ?3 °C (27 °F); it remains liquid below the normal freezing point because of high pressure from the weight of the ice above it. Geothermal heat from the Earth's interior warms the bottom of the lake."

How much longer are you carrying on with this charade of ignorance in the face of facts?

[The Natural Philosopher]

Bwahaha!

[The Natural Philosopher]

Forever, old son.

People like Dennis HAVE TO BELIEVE they are right.

For them, the recieved knowledge they have, is never examined, never modified, but is immaculate, perfect and eternal. Dennis thinks, after all, that he is God.

[Fredxx]

It's sad that he has some good points, that rock acts as an insulator, and the continuous flow of heat is limited from any drilling. But he needs to accept that the flow is at least "positive".

I've been long fascinated with Lake Vostok which has come back in the limelight with collaborative programs to send probes to Jupiter's Europa.

[The Natural Philosopher]

well it is somewhat between an insulator and a conductor.

Otherwise GSHP wouldn't work at all..

But its right to say that it limits geothermal extraction where there is no local magma. It doesn't prevent it..an old mine can be pumped for many years before heat output goes down to a steady and lower value. It does not stop though.

and

Indeed.

Viz

"The Earth's internal heat naturally flows to the surface by conduction at a rate of 44.2 terawatts, (TW,) [20] and is replenished by radioactive decay of minerals at a rate of 30 TW. [21] These power rates are more than double humanity?s current energy consumption from all primary sources, but most of it is not recoverable. In addition to heat emanating from deep within the Earth, the top ten metres of the ground accumulates solar energy (warms up) during the summer, and releases that energy (cools down) during the winter.

Beneath the seasonal variations, the geothermal gradient of temperatures through the crust is 25-30 °C per kilometre (km) of depth in most of the world. The conductive heat flux is approximately

0.1 MW/km2 on average. These values are much higher near tectonic plate boundaries where the crust is thinner. They may be further augmented by fluid circulation, either through magma conduits, hot springs, hydrothermal circulation or a combination of these.

A geothermal heat pump can extract enough heat from shallow ground anywhere in the world to provide home heating, but industrial applications need the higher temperatures of deep resources. [1] The thermal efficiency and profitability of electricity generation is particularly sensitive to temperature. The more demanding applications receive the greatest benefit from a high natural heat flux, ideally from using a hot spring. If no hot spring is available, the next best option is to drill a well into a hot aquifer. If no adequate aquifer is available, an artificial one may be built by injecting water to hydraulically fracture the bedrock. This last approach is called hot dry rock geothermal energy in Europe, or enhanced geothermal systems in North America. Much greater potential may be available from this approach than from conventional tapping of natural aquifers. [5] "

The problem with geothermal is that as stated the heat flux is only about 0.1W per square meter. compared with a couple 40-200 W from insolation.(UK)

so a typical 1-2KW average domestic usage represents about 10-20,000 square meters.of land area that you need to 'rob' of geothermal heat. sort of football pitch sized.

But efficiencies are better, as you can get boiling water a couple of Km down.

Its interesting to see who much solar energy per head of population greater London receives.

Its area is about 1600 square kilometers, and there are about 5M people in it, so every person has about 300 sq meters of land if allocated evenly.

So somewhere between 12Kw and 60Kw of average solar energy per head in greater London.

Probably ten times more than the space heating requirements of london, so a 10% efficient (in terms of converting ground stored insolation to hot water) pump could in theory heat the whole of london perfectly adequately. Especially if air con pumped heat back into the ground in summer.

[geoff]

In message , "dennis@home" writes

And there I was making such an effort to stay out of this thread and sit back and eat the popcorn but ...

Oh Pennis you are such a stupid thick d*****ad, I just couldn't let this one go. Drilling a hole (a gnats fart of f*ck all energy in the great scheme of things) changing the temperature of cubic kms of water?

I don't think so

As usual you have no sense of proportion

You stupid, stupid eejit

What little credibility you had is now well and truly gone

(Apart from the fact that you couldn't just give a straight answer to the question above)