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So what is the correct figure, and where do you get it from?

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says that you have to go three metres down their particular bore-hole to get around a six month lag.

The paper seems to date from December 2017 and clearly isn't the source I've been citing (which is merely something I thought that I remembered).

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Bill Sloman, Sydney
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bill.sloman
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In Nicosia it is closer to three metres than 50cm down one particular bore-hole. Quite how krw might find out what's "obvious to a sane person" is something of a mystery. He only trusts what he already knows, and he clearly isn't sane.

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Bill Sloman, Sydney
Reply to
bill.sloman

On Sunday, April 8, 2018 at 11:59:04 PM UTC-4, snipped-for-privacy@ieee.org wrote: .

the temperature by 180 degrees. But it is not true.

get around a six month lag.

've been citing (which is merely something I thought that I remembered).

Like you the source I remember is something I saw a long time ago and I do not know where I saw it. But if you look at Figure 1 of the source you fou nd, the 0 meter depth has a minimum at about day 35 , the

1 meter depth has a minimum at about day 90 and the 2 meter depth has a min imum at about day 150. and the 4 meter depth has a minimum at about day 210 . So 180 days from the 0 meter minimum is almost 180 degrees out of phase with the temperature minimum at 4 meters. The 20 meter temperature minimum is hard to estimate from the chart , but is about 180 degrees from the 0 m eter depth.

But the temperture change at 4 meters is only about 2.5 degrees C. and not significant as far as a geothermal heat pump.

But in all cases the lag at 50 cm is not close to 180 degrees.

Around here geothermal heat sinks are usually about 6 feet because that is a reasonable depth for a back hoe and the system does not depend on any the rmal lag.

Dan

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dcaster

gs the temperature by 180 degrees. But it is not true.

o get around a six month lag.

I've been citing (which is merely something I thought that I remembered).

o not know where I saw it. But if you look at Figure 1 of the source you f ound, the 0 meter depth has a minimum at about day 35 , the

inimum at about day 150. and the 4 meter depth has a minimum at about day 2

  1. So 180 days from the 0 meter minimum is almost 180 degrees out of phas e with the temperature minimum at 4 meters. The 20 meter temperature minimu m is hard to estimate from the chart , but is about 180 degrees from the 0 meter depth.

ot significant as far as a geothermal heat pump.

It's a particular example. What we are looking at is distributed resistor/c apacitor network. The heat capacity of the soil isn't going to constant fro m one site to the next,or even with changing depth on a single site, and th e thermal resistance isn't going to be any more predictable.

If you want to have an opinion on the subject, go and find some more data. So far you have just been carping.

s a reasonable depth for a back hoe and the system does not depend on any t hermal lag.

Well, it wouldn't. I don't think that I ever suggested that it might. Tempe rature variation does decrease rapidly with depth, which was the point I wa s trying to make.

The paper I originally cited (which you snipped, and probably didn't look a t) was about putting your geothermal heat sink under your slab, rather than drilling a longish bore hole.

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You do put a lot of effort into looking like a spiteful kind of trivial twi t. With a bit more effort you could elevate yourself to being a patronisng trivial twit, but you can't raise your game even that far.

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Bill Sloman, Sydney
Reply to
bill.sloman

Sounds like the worst of all possibilities. A terrible idea for putting in a geothermal unit in an existing house. Not a good idea if pipe is ground springs a leak. And it would be cooling the slab when you are trying to heat the house. Dan

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dcaster

ok at) was about putting your geothermal heat sink under your slab, rather than drilling a longish bore hole.

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in a geothermal unit in an existing house.

Obviously. A bore hole in the garden is a much better solution for an exist ing house.

Plumbing gets buried in the slab too - if it leaks you have to jack-hammer into the slab to get at the leaking pipe. Clearly, these kinds of leaks are rare.

My parents copped a variation of this when the crooked plumbing sub-contact or used copper pipe in the visible bits, and iron in the connection to the municipal water supply. After twenty years, the iron pipe had corroded to a n extent that perceptibly impeded water flow, so they offending pipe had to be exposed and replaced. It was expensive and inconvenient, but perfectly practical.

There's nothing to stop you burying a couple of inches of expanded polystyr ene, rigid isocyanate foam or the like between the slab and the thermal res ervoir.

A foot or so of dry dirt might be enough.

Since the report I cited - the one you keep in snipping, without marking th e snip - was published by the US Department of Energy, it's clearly not a " terrible idea". You may be terrified by it, but you clearly can't do quanti tative thinking - one might have expected that your elite education might h ave been able to instil this skill, as it mostly does in the students they let in.

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Bill Sloman, Sydney
Reply to
bill.sloman

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