ground source heating

[The Natural Philosopher]

Have you been down a mile deep cave, Dennis.?

I HAVE been down deep mines.

I am not lying.

Oh really. Ypou mean that all that solid rock they are in contact with is a perfect insulator.

Read on. As you get deeper, the heat rises. Due to getting near the earth's core.

You didnt bother to read hat bit though.

I originally said, that the top 100 meters or so is more or less constant temperature from the median of the air temp. About 9C in this part of the world. Below that it gets hotter and hotter.

more dickbrained half assed analsyis.

[The Natural Philosopher]

That might work then.

[dennis]

No one said you were AFAICS.

OK so explain where the extra energy is going to come from? You stated that it comes from the Sun. You posted a link that says the same. I happen to agree. So if the housing density is high as it is here just explain where the energy is going to come from if there are suddenly a lot of bore holes sucking heat out of the ground. Just do the maths and state how many square meters of land are needed per dwelling if you are so certain you are right. As an approximation I will assume the 200m run of pipe work spaced no closer than 2m implies the experts think you need 400 m2.

[Man at B&Q]

qpp$jd0$ [e-mail]...

That's not a "bore hole", FFS.

MBQ

[dennis]

Sod off you are about as useful as drivel.

[Man at B&Q]

I'm beginning to think you ARE Drivel, or a close relation.

A "bore hole" GSHP is a vertical system, probably a sq m or two all in surface area. Not "200m run of pipe work spaced no closer than 2m implies the experts think you need 400 m2"

If you don't like being corrected, don't post crap in the first place.

MBQ

[dennis]

So you think its going to get all its solar energy out of a 4 m2 space, you really are being stupid.

Don't start arguing again I don't like having to call you stupid and I like it even less when you are so obviously stupid.

[Andy Champ]

Apparently the earth's core shoves about about 4x10^13W and is about

5x10^14 square metres. About 0.1W / square metre. It better be insolation...

However you can get it from your neighbour's gardens and ground water - unless you all start doing it.

Now how's about this idea:

Get yourself a water-cooled generator. Feed the coolant into your heating system, motor will run happily with coolant around boiling so that's easy. That's maybe a third of your energy with conventional CHP.

Another third comes out as mechanical energy, you can run a heat pump with that or make electricity and use that. Again, conventional CHP.

The last third comes out as the hot exhaust. Why not blow that on the cold end of a heat pump? Take it down to near freezing and you've even got most of the latent heat of condensation from the water.

Andy

[Man at B&Q]

[e-mail]...

A *BORE HOLE* goes deep enough not require recharging from solar energy.

A system of pipe laid out over a large area may well require solar recharging, I leave that to others.

You seem unable to distinguish between the two.

It takes two to argue.

Kettle, pot, black.

MBQ

[dennis]

messagenews: [e-mail]...

A 200m borehole is not deep enough to tap into geothermal energy in the UK. Try posting to alt.iceland.D-I-Y.

You obviously can't so don't waste peoples time.

[andrew]

10 years ago we had a 3 cylinder Lister with an asynchronous (capacitively excited) 10kVA genset. We achieved around 20% conversion of fuel to electricity. In those days the fuel cost/kWhr was about the same as grid electricity/kWhr, now it's double.

We reckoned 33% waste heat to coolant 66% to exhaust, the 33% was enough for our purposes. The big problem that hit conversion efficiency was sizing the genset for the peak load and only averaging about 20% of that. I'd do it differently now. The O+M costs of running 2000+ hours/year aren't insignificant nor the capital depreciation on GBP4000 genset cost then.

AJH

[The Natural Philosopher]

But the solar energy comes from the whole area..each persons house occupies a LOT more than that area.

more than enough for the average household as it happens. If mutiplied by 50% (pump factor) and if taken as an average.

average insolation is about 100W/sq meter. Over the year.

Typical outside temps are an average of 9C, so for say 19C indoors, that's a 10C drop.

Taking a smallish house as a cube of say 100 sq meters floor area, total external area is 600 sq meters.

That will in some way be warming the ground it stands on at a rate of

10,000W - 10KW average.

so to achieve thermal balance we need a U value of 10000/600 divided by

10 degrees C. about about 1.6 or so. Well within current standards.

Ergo a house receives enough solar energy to completely heat it. Provided that the ground under it gets the benefit of that warmth in summer, and its pumped out again in winter.

[The Natural Philosopher]

messagenews: [e-mail]...

That is irrelevant. The borehole taps stored heat from the whole mass surrounding it. Essentially what counts is how much area of ground it 'has to itself.

It cant be smaller than the plot of land the house stands on, and as I have shown, that's adequate to heat the subsoil more than enough in the summer.

when the blind lead the blind, they both shall fall into a ditch.

If you examine the numbers you find out what GSHP works, and solar panels dont.

The solar panel collects from at best a few square meters. The GSHP, even in a borehole scenario, collects from several hundreds.

>

[<me9]

There are (were before MT closed them down) hot mines and cold mines, wet mines and dry mines gassy mines and safe mines. It all depends on the geological conditions.

[dennis]

messagenews: [e-mail]...

No you haven't. You have quoted a load of guff that is inconstant with the stuff you have previously quoted. You even invented some sort of irrelevant cube to create a bigger m2 figure in the hope we wouldn't notice. If the land area was enough I wouldn't need a bore hole and all the companies say I do. A bore hole is just a way of "stealing" some of the heat from the neighbours AFAICS and will soon cause trouble if everyone does. The only way I can see a bore hole working well is if I use active cooling in the summer and shove the heat back down the hole.

I have examined the numbers and someone is making them up. You either need the area to put the collectors in or you don't, there is no magical increase in available area just because you sink a borehole. I have no doubt that boreholes work ATM, they are few and very far between, however its a lot of cash to put down a hole only to find that the neighbours all do the same and make it not work in twenty years time.

[Roger Chapman]

I am intrigued. Caves with a vertical depth of more than a mile, where in the world is that? But perhaps more pertinent to temperature at depth where in the world will you find an unflooded cave below local sea level let alone a mile below.

[The Natural Philosopher]

No they were not cold mines. They were coal mines.

All mines get hot as you go deeper.

[The Natural Philosopher]

fascinating article here.

a mile below ground, temps of 120F.

[Dave Liquorice]

there are quite a few with that sort of depth but it probably isn't in a continuous vertical drop.

The South African diamond and gold mines are 3.5km deep and are heading for 5km at such depths the temp is 70C...

But perhaps more pertinent to temperature at depth where in the world

Donno if the deepest caves listed above go below sea level or not but don't forget the heat will tend to be the same at the same depth from the surface (assuming the mantle is at the same depth).

[Dave Liquorice]

Our absloute peak load is just over 7kW at breakfast with a ring on for porridge, grill on for toast, kettle on for tea and coffee machine on for coffee. Our base load is about 1kW or 15% ish.

Most other peaks are around 3kW from the kettle they could be knocked back by not having a rapid boil kettle of course.

Would that be a battery bank and 10kW invertor to meet the peaks with a smaller set to provide base load and top the batteries up?