I was watching a building program yesterday, and the builder said it was
12c constantly 2 metres underground. They was building a house in
Maidstone, Kent.

I know builders are known for telling porkies, but is it true that just
2 metres underground the temperature is constant?
--
Joe Egginton
Wolverhampton
175m asl

"Joe Egginton" wrote in message
...
I was watching a building program yesterday, and the builder said it was
12c constantly 2 metres underground. They was building a house in
Maidstone, Kent.

I know builders are known for telling porkies, but is it true that just 2
metres underground the temperature is constant?
--
Joe Egginton
Wolverhampton
175m asl

Hmmm I wonder how that squares with heatpumps? May that's the temp they
bring the mains up to.

"Lawrence Jenkins" wrote in message
...
|
| "Joe Egginton" wrote in message
| ...
| I was watching a building program yesterday, and the builder said it was
| 12c constantly 2 metres underground. They was building a house in
| Maidstone, Kent.
|
| I know builders are known for telling porkies, but is it true that just
2
| metres underground the temperature is constant?
| --
| Joe Egginton
| Wolverhampton
| 175m asl
|
| Hmmm I wonder how that squares with heatpumps? May that's the temp they
| bring the mains up to.
|
|
Your builder was right. Sub-soil temperatures in the UK are standard at
about 50F (10C). This applies from 2 feet down to a couple of hundred feet,
but may vary depending on the depth of the water table. This is why
underground caves are always at pretty much the same temperature throughout
the year irrespective of surface weather conditions.

To use geothermal heat pumps, you would have to drill down a couple of miles
before finding any appreciable rise in temperature, and then the deeper you
go, the hotter it gets. Generally, for every kilometre depth, the
temperature rises by about 30C, so at 3km, the rock temperature will be 90C
above the surface temperature, enough to produce boiling water.

The above figures are not necessarily true in areas of volcanic activity,
and especially suspect in places like Iceland!

jim, Northampton

On Jun 14, 11:54*pm, Joe Egginton wrote:
I was watching a building program yesterday, and the builder said it was
12c constantly 2 metres underground. *They was building a house in
Maidstone, Kent.

I know builders are known for telling porkies, but is it true that just
2 metres underground the temperature is constant?
--
Joe Egginton
Wolverhampton
175m asl

Pretty well true. The temperature will be equal to the long-term
average air temperature. 12°C seems a bit high, even for Maidstone.
Probably 11°C.

Tudor Hughes, Warlingham, Surrey.

"Joe Egginton" wrote:

I was watching a building program yesterday, and the builder said it was
12c constantly 2 metres underground. They was building a house in
Maidstone, Kent.

I know builders are known for telling porkies, but is it true that just 2
metres underground the temperature is constant?
--

I found this:

"The range of temperature diminishes quickly below the soil surface.
The day-night and summer-winter fluctuations are still evident but
there is a delay in the time of maxima (and minima) because the
conduction of heat downwards continues after the time of maximum
heating by the sun. In lowland Britain, at 8cm (3in) below the surface
the extreme temperature are around 24°C and -4°C, and 30cm (1ft)
down 21°C and 0°C. Thus only in the very coldest winters does frost
penetrate to a depth greater than one foot.

By the time we get 60cm (2ft) down the temperature variation
between day and night is very small, less than 2degC, warmest
early-evening and coldest mid-morning. Once we reach 90cm
(3ft) - the precise depth varies with soil type - the diurnal
fluctuation disappears altogether.

And at 1.2m (4ft) the highest reading, typically 17°C, occurs in
early-September while the lowest reading, about 4°C is usually
obtained in early-March. Day-to-day temperature changes at
this depth are always very small, measured in fractions of a degree.

Measurements at greater depths are not normally made, but a
series of observations were taken by a Colonel H.S. Knight at
Harestock, near Winchester, in the 1890s. His records showed
that at 3m (10ft) the temperature ranged from 7.9C in April to
11.7C in October, and at 6m (20ft) the warmest month was
December with 10.4°C and the coldest July with 9.5°C.

At 9m (30ft) there was no evident annual cycle and all months fell
between 9.6°C and 10.2°C. At 20m (66ft) the temperature appeared
to be constant at exactly 10.0°C."

Philip

"Philip Eden" philipATweatherHYPHENukDOTcom wrote in message
...
At 9m (30ft) there was no evident annual cycle and all months fell
between 9.6°C and 10.2°C. At 20m (66ft) the temperature appeared
to be constant at exactly 10.0°C."

This may well be a stupid question, but in view of the figures above, why
does the London underground get unbearably hot during hot weather?
Shouldn't it stay roughly the same all year round?
--
Hungerdunger
To reply by email, remove the MARX from my address

hungerdunger wrote:
"Philip Eden" philipATweatherHYPHENukDOTcom wrote in message
...
At 9m (30ft) there was no evident annual cycle and all months fell
between 9.6°C and 10.2°C. At 20m (66ft) the temperature appeared
to be constant at exactly 10.0°C."

This may well be a stupid question, but in view of the figures above, why
does the London underground get unbearably hot during hot weather?
Shouldn't it stay roughly the same all year round?

Presumably people

--
Joe Egginton
Wolverhampton
175m asl

On Mon, 15 Jun 2009 23:45:45 +0100, "hungerdunger"
wrote:

"Philip Eden" philipATweatherHYPHENukDOTcom wrote in message
.. .
At 9m (30ft) there was no evident annual cycle and all months fell
between 9.6? and 10.2?. At 20m (66ft) the temperature appeared
to be constant at exactly 10.0?."

This may well be a stupid question, but in view of the figures above, why
does the London underground get unbearably hot during hot weather?
Shouldn't it stay roughly the same all year round?

100W+ per person, a couple of MW per train. It all ends up as heat.


--
Regards, Paul Herber, Sandrila Ltd. http://www.sandrila.co.uk/

In article . net,
Paul Herber wrote:
On Mon, 15 Jun 2009 23:45:45 +0100, "hungerdunger"
wrote:

"Philip Eden" philipATweatherHYPHENukDOTcom wrote in message
.. .
At 9m (30ft) there was no evident annual cycle and all months fell
between 9.6? and 10.2?. At 20m (66ft) the temperature appeared
to be constant at exactly 10.0?."

This may well be a stupid question, but in view of the figures above, why
does the London underground get unbearably hot during hot weather?
Shouldn't it stay roughly the same all year round?

100W+ per person, a couple of MW per train. It all ends up as heat.

Note that the trains don't have regenerative braking either!

--
Rodney Blackall (retired meteorologist)(BSc, FRMetS)
Buckingham, ENGLAND
Using Acorn SA-RPC, OS 4.02 with ANT INS and Pluto 3.03j

"Paul Herber" wrote in message
ell.net...

100W+ per person, a couple of MW per train. It all ends up as heat.

Yes, but from my (now possibly incorrect) memory of living in London many
years ago, I seem to remember the Tube was OK in cool weather, but very hot
in hot weather. My point was: shouldn't the temperature be relatively
stable all year round?

--
Hungerdunger
To reply by email, remove the MARX from my address