My son will soon be building a new house and intends to install a ground
source heat pump, hopefully as a main source of hear in conjunction with
solar panels.
He will be location the underground pipework in a pond beside the house.
The pond may be about 150 metres by 50 metres by 1.5 metres deep; it is in
Perthshire.
Does amyone have experience of ground source heating? How effective is it?
Can it ever act even for a short while as the primary heat source?
Is there an independant body that would give professional advice?
Thank you.

On Jan 30, 6:36 pm, "Stewart" wrote:
My son will soon be building a new house and intends to install a ground
source heat pump, hopefully as a main source of hear in conjunction with
solar panels.
He will be location the underground pipework in a pond beside the house.
The pond may be about 150 metres by 50 metres by 1.5 metres deep; it is in
Perthshire.
Does amyone have experience of ground source heating? How effective is it?
Can it ever act even for a short while as the primary heat source?
Is there an independant body that would give professional advice?
Thank you.

that sounds more like "water source heat pump"?
try a google?

Cheers
JimK

Stewart wrote:
My son will soon be building a new house and intends to install a ground
source heat pump, hopefully as a main source of hear in conjunction with
solar panels.

Good idea, except teh solar panels

He will be location the underground pipework in a pond beside the house.
The pond may be about 150 metres by 50 metres by 1.5 metres deep; it is in
Perthshire.

Definitely forget the solar panels.

I doubt the pond will be good enough..may need to use soil. Any fish
will suffer. A lot of ours are dead in a 1.5m pond anyway after these
frosts.



Does amyone have experience of ground source heating?

Yes and no. Did teh calc and decided it would have been a good original
install, but would cost too much to retrofit.

How effective is it?

Very.
Can it ever act even for a short while as the primary heat source?

All the time. No need for anything else.Only problem is cracking out
heat much above 45C. You will need large radiators or dense UFH to use
heat that low grade, and hot water will need an immersion top or a two
stage heat pump.


Is there an independent body that would give professional advice?

Pass.

Thank you.

In message , The Natural Philosopher
writes
Stewart wrote:
My son will soon be building a new house and intends to install a
ground source heat pump, hopefully as a main source of hear in
conjunction with solar panels.

Good idea, except teh solar panels

He will be location the underground pipework in a pond beside the
house. The pond may be about 150 metres by 50 metres by 1.5 metres
deep; it is in Perthshire.

Definitely forget the solar panels.

I doubt the pond will be good enough..may need to use soil. Any fish
will suffer. A lot of ours are dead in a 1.5m pond anyway after these
frosts.

Really ? mine are all OK here in a smaller pond
(just been out to check... )


--
geoff

"Stewart" wrote in message
...
My son will soon be building a new house and intends to install a ground
source heat pump, hopefully as a main source of hear in conjunction with
solar panels.
He will be location the underground pipework in a pond beside the house.
The pond may be about 150 metres by 50 metres by 1.5 metres deep; it is in
Perthshire.
Does amyone have experience of ground source heating? How effective is
it? Can it ever act even for a short while as the primary heat source?
Is there an independant body that would give professional advice?
Thank you.

It sounds like you can get useful heat from that size of lake, i have just
installed a GSHP on my place which is 170sqm of floor space. Its a 2kw/12kw
Heat Pump, but we use 600m of ground loop, some of it in a well.

Steve

In message , The Natural Philosopher
writes
Stewart wrote:
My son will soon be building a new house and intends to install a
ground source heat pump, hopefully as a main source of hear in
conjunction with solar panels.

Good idea, except teh solar panels

He will be location the underground pipework in a pond beside the
house. The pond may be about 150 metres by 50 metres by 1.5 metres
deep; it is in Perthshire.

Definitely forget the solar panels.

I doubt the pond will be good enough..may need to use soil. Any fish
will suffer. A lot of ours are dead in a 1.5m pond anyway after these
frosts.

That's a big pond. The pipe will be on the bottom where the water
temperature cannot fall below 4deg.C. (fishes lifeline) unless frozen
down to 1.5m.



Does amyone have experience of ground source heating?

Yes and no. Did teh calc and decided it would have been a good original
install, but would cost too much to retrofit.

How effective is it?

Very.
Can it ever act even for a short while as the primary heat source?

All the time. No need for anything else.Only problem is cracking out
heat much above 45C. You will need large radiators or dense UFH to use
heat that low grade, and hot water will need an immersion top or a two
stage heat pump.

What about ducted air?


Is there an independent body that would give professional advice?

Pass.

There was a thread on this. Gentleman from Ireland AIR.

regards

--
Tim Lamb

In message , Mr Sandman
writes

"Stewart" wrote in message
...
My son will soon be building a new house and intends to install a
ground source heat pump, hopefully as a main source of hear in
conjunction with solar panels.
He will be location the underground pipework in a pond beside the
house. The pond may be about 150 metres by 50 metres by 1.5 metres
deep; it is in Perthshire.
Does amyone have experience of ground source heating? How effective
is it? Can it ever act even for a short while as the primary heat
source?
Is there an independant body that would give professional advice?
Thank you.

It sounds like you can get useful heat from that size of lake, i have
just installed a GSHP on my place which is 170sqm of floor space. Its a
2kw/12kw Heat Pump, but we use 600m of ground loop, some of it in a well.

I'm close to the River Lea which is quite warm near the main source at
East Hyde sewage works.

My bright idea was to pump water from a shallow well, through a heat
exchanger supplying the heat pump and then back to a second well further
down the valley.

When I put this to the EA they batted it back with a reference to their
abstraction and discharge limits and a pointer to their charges.
Somebody here kindly calculated how much heat could be recovered from
the 20cu.m allowed abstraction. From memory this was only a few kWh.

regards

--
Tim Lamb

"The Natural Philosopher" wrote in message
...
Any fish will suffer. A lot of ours are dead in a 1.5m pond anyway after
these frosts.


What normally does for the fish is lack of oxygen rather than cold. If you
had a solid layer of ice covering the whole surface area the oxygen levels
could easily have dropped too low. Many pond owners have a small heater
which keeps just a tiny patch clear, we have a fountain which does the same
although in the last big freeze-up it only managed to preserve a very small
patch.

The other problem can be frogs. They have a nasty habit of dying in the
cold and decomposing in the water which poisons it.

Tim Lamb wrote:


My bright idea was to pump water from a shallow well, through a heat
exchanger supplying the heat pump and then back to a second well further
down the valley.

Why the open loop?

Just store enough water-propanol mix for the circuit and pump it up and down
the river bed.

AJH

On Sun, 31 Jan 2010 09:14:10 +0000, Tim Lamb wrote:

I doubt the pond will be good enough..may need to use soil. Any
fish
will suffer. A lot of ours are dead in a 1.5m pond anyway after
these
frosts.

But probably from suffocation from ice cover or gases from
decompostion in the pond base rather than the cold.

That's a big pond. The pipe will be on the bottom where the water
temperature cannot fall below 4deg.C. (fishes lifeline) unless frozen
down to 1.5m.

Naturally yes the bottom of a pond stays about 4C as that is the temp
that water is the densist but you will be pumping heat out of the
bottom of the pond thus setting up a circulation...

New build these days with good to high insulation levels a GSHP
system is almost a no brainer. High capital cost but *much* lower
fuel bills.

--
Cheers
Dave.

Dave Liquorice wrote:
On Sun, 31 Jan 2010 09:14:10 +0000, Tim Lamb wrote:

I doubt the pond will be good enough..may need to use soil. Any
fish
will suffer. A lot of ours are dead in a 1.5m pond anyway after
these
frosts.

But probably from suffocation from ice cover or gases from
decompostion in the pond base rather than the cold.

That's a big pond. The pipe will be on the bottom where the water
temperature cannot fall below 4deg.C. (fishes lifeline) unless frozen
down to 1.5m.

Naturally yes the bottom of a pond stays about 4C as that is the temp
that water is the densist but you will be pumping heat out of the
bottom of the pond thus setting up a circulation...

New build these days with good to high insulation levels a GSHP
system is almost a no brainer. High capital cost but *much* lower
fuel bills.



I calculated the break even price was about at 45p a liter for oil.

It doesn't do a lot unless you are using nuclear electric though, cos
otherwise electricity steps up along with the gas and oil that produce it.

capital cost £10-£15k probably.

New build its a no brainer. Retrofitting it - its a bugger. everything
up to and including hot water tanks has to change really. Larger bore
pipework, bigger heat exchangers in the tanks, bigger rads or UFH..

The Natural Philosopher wrote:
Dave Liquorice wrote:
On Sun, 31 Jan 2010 09:14:10 +0000, Tim Lamb wrote:

I doubt the pond will be good enough..may need to use soil. Any
fish
will suffer. A lot of ours are dead in a 1.5m pond anyway after
these
frosts.

But probably from suffocation from ice cover or gases from
decompostion in the pond base rather than the cold.

That's a big pond. The pipe will be on the bottom where the water
temperature cannot fall below 4deg.C. (fishes lifeline) unless frozen
down to 1.5m.

Naturally yes the bottom of a pond stays about 4C as that is the temp
that water is the densist but you will be pumping heat out of the
bottom of the pond thus setting up a circulation...

New build these days with good to high insulation levels a GSHP
system is almost a no brainer. High capital cost but *much* lower
fuel bills.


I calculated the break even price was about at 45p a liter for oil.

It doesn't do a lot unless you are using nuclear electric though, cos
otherwise electricity steps up along with the gas and oil that produce it.

capital cost £10-£15k probably.

New build its a no brainer. Retrofitting it - its a bugger. everything
up to and including hot water tanks has to change really. Larger bore
pipework, bigger heat exchangers in the tanks, bigger rads or UFH..

Don;t know about that....
We retro-fitted a GSHP here a couple of years back - original boiler was
a conventional oil-fired boiler. We did have to replace the hot water
cylinder because the coil was too small (wasn't transferring the heat
from the heat pump fast enough) - but we retained the existing radiators
and all's fine in that department.

Water from the heat-pump is circulating at about 45c - we've recently
started using the electric immersion for an hour each night just to top
off the hot water as the two of us like a bath in quick succession, and
the unassistaed tank wasn't quite hot enough - but, apart from that,
it's all fine.

Installation of the collector coils was made easier as we had a large
dip in the garden that needed to be infilled anyway - so we just dug
trenches in it and then dumped tonnes of soil on top !

All-in costs about 12k euro - less a 30% grant from the Irish Government.

Adrian

In message , andrew
writes
Tim Lamb wrote:


My bright idea was to pump water from a shallow well, through a heat
exchanger supplying the heat pump and then back to a second well further
down the valley.

Why the open loop?

Just store enough water-propanol mix for the circuit and pump it up and down
the river bed.

I doubt the fisheries dept. would allow anything to be installed in the
river itself. The most convenient bit has a flow rate of 4 knots or so
anyway.

At the moment I don't have a project requiring heat but, come the day I
finish the current barn rebuild, the old dairy/woodwork shop is
redundant and available for conversion. I would like to be able to offer
the planners something green by way of heating.

There are two alternatives. The old Cress ditch could be deepened, about
70m x 7m so small compared with the OP. There is also the grass strip
between that and the river which is 100m x 20m (assuming the EA allows
slinkies within 8m of the actual bank).

regards

--
Tim Lamb

All-in costs about 12k euro - less a 30% grant from the Irish Government.

If you don't mind me asking, how have your gas / electric bills
varied since it was fitted ?

Colin Wilson wrote:
All-in costs about 12k euro - less a 30% grant from the Irish Government.

If you don't mind me asking, how have your gas / electric bills
varied since it was fitted ?

HI Colin

Well - the original boiler was oil-fired (out here the only gas comes in
bottles!) - so I guess a fairer comparison would be CH oil + other
electric Vs all-electric....

I'll see if I can find out - haven't actually done the sums...
but if I can find the bills then I'll let you know

Adrian

"Calvin Sambrook" wrote in message
...
"The Natural Philosopher" wrote in message
...
Any fish will suffer. A lot of ours are dead in a 1.5m pond anyway after
these frosts.


What normally does for the fish is lack of oxygen rather than cold. If
you had a solid layer of ice covering the whole surface area the oxygen
levels could easily have dropped too low. Many pond owners have a small
heater which keeps just a tiny patch clear, we have a fountain which does
the same although in the last big freeze-up it only managed to preserve a
very small patch.

The other problem can be frogs. They have a nasty habit of dying in the
cold and decomposing in the water which poisons it.


I wonder if the filter has frozen?
Plays havoc with small ponds if you don't have a good filter 24x7.
Mine hasn't frozen yet even in these cold spells.

dennis@home wrote:


"Calvin Sambrook" wrote in message
...
"The Natural Philosopher" wrote in message
...
Any fish will suffer. A lot of ours are dead in a 1.5m pond anyway
after these frosts.


What normally does for the fish is lack of oxygen rather than cold.
If you had a solid layer of ice covering the whole surface area the
oxygen levels could easily have dropped too low. Many pond owners
have a small heater which keeps just a tiny patch clear, we have a
fountain which does the same although in the last big freeze-up it
only managed to preserve a very small patch.

The other problem can be frogs. They have a nasty habit of dying in
the cold and decomposing in the water which poisons it.


I wonder if the filter has frozen?
Plays havoc with small ponds if you don't have a good filter 24x7.
Mine hasn't frozen yet even in these cold spells.
what filetr?

This is just a hole in the ground full of water mate.

about 3x5 meters and about 2 meters deep. at its deepest.

"The Natural Philosopher" wrote in message
...
dennis@home wrote:


"Calvin Sambrook" wrote in message
...
"The Natural Philosopher" wrote in message
...
Any fish will suffer. A lot of ours are dead in a 1.5m pond anyway
after these frosts.


What normally does for the fish is lack of oxygen rather than cold. If
you had a solid layer of ice covering the whole surface area the oxygen
levels could easily have dropped too low. Many pond owners have a small
heater which keeps just a tiny patch clear, we have a fountain which
does the same although in the last big freeze-up it only managed to
preserve a very small patch.

The other problem can be frogs. They have a nasty habit of dying in the
cold and decomposing in the water which poisons it.


I wonder if the filter has frozen?
Plays havoc with small ponds if you don't have a good filter 24x7.
Mine hasn't frozen yet even in these cold spells.
what filetr?

This is just a hole in the ground full of water mate.

about 3x5 meters and about 2 meters deep. at its deepest.


Ah, a natural fish killer.
A lot will die every so often, some will probably survive to restock it.
A pump and a reed bed filter will work wonders.

"Stewart" wrote in message
...
My son will soon be building a new house and intends to install a ground
source heat pump, hopefully as a main source of hear in conjunction with
solar panels.
He will be location the underground pipework in a pond beside the house.
The pond may be about 150 metres by 50 metres by 1.5 metres deep; it is in
Perthshire.
Does amyone have experience of ground source heating? How effective is
it? Can it ever act even for a short while as the primary heat source?
Is there an independant body that would give professional advice?
Thank you.
Thanks all who replied:-
He is now thinking of a large area of solar panels coupled with as much
insulation as it is possible to incorporate in the walls.
Might use a high energy wood pellet furnace as back up source of heating the
house and swimming pool.

On 01/02/2010 13:30, Stewart wrote:
He is now thinking of a large area of solar panels coupled with as much
insulation as it is possible to incorporate in the walls.
Might use a high energy wood pellet furnace as back up source of heating the
house and swimming pool.

It's more efficient to design for passive solar than to try and use roof
mounted solar panels for heating. It's quite a tall order though!

There will need to be a lot of emphasis place on the details of
insulation and air-tightness to make it work properly - and most
builders aren't experienced in this yet.

Jim, he has already been advised that he will need air conditioning in the
summer because of the amount and quality of the insulation - solar panels
should operate this.


"Jim" wrote in message
...
On 01/02/2010 13:30, Stewart wrote:
He is now thinking of a large area of solar panels coupled with as much
insulation as it is possible to incorporate in the walls.
Might use a high energy wood pellet furnace as back up source of heating
the
house and swimming pool.

It's more efficient to design for passive solar than to try and use roof
mounted solar panels for heating. It's quite a tall order though!

There will need to be a lot of emphasis place on the details of insulation
and air-tightness to make it work properly - and most builders aren't
experienced in this yet.

dennis@home wrote:


"The Natural Philosopher" wrote in message
...
dennis@home wrote:


"Calvin Sambrook" wrote in message
...
"The Natural Philosopher" wrote in message
...
Any fish will suffer. A lot of ours are dead in a 1.5m pond anyway
after these frosts.


What normally does for the fish is lack of oxygen rather than cold.
If you had a solid layer of ice covering the whole surface area the
oxygen levels could easily have dropped too low. Many pond owners
have a small heater which keeps just a tiny patch clear, we have a
fountain which does the same although in the last big freeze-up it
only managed to preserve a very small patch.

The other problem can be frogs. They have a nasty habit of dying in
the cold and decomposing in the water which poisons it.


I wonder if the filter has frozen?
Plays havoc with small ponds if you don't have a good filter 24x7.
Mine hasn't frozen yet even in these cold spells.
what filetr?

This is just a hole in the ground full of water mate.

about 3x5 meters and about 2 meters deep. at its deepest.


Ah, a natural fish killer.
A lot will die every so often, some will probably survive to restock it.
A pump and a reed bed filter will work wonders.

Don't be silly. It gets fed loads of oxygenated rainwater, and that
seeps away into the subsoil.constantly renewed and plenty of oxygenating
plants

Jim wrote:
On 01/02/2010 13:30, Stewart wrote:
He is now thinking of a large area of solar panels coupled with as much
insulation as it is possible to incorporate in the walls.
Might use a high energy wood pellet furnace as back up source of
heating the
house and swimming pool.

It's more efficient to design for passive solar than to try and use roof
mounted solar panels for heating. It's quite a tall order though!

There will need to be a lot of emphasis place on the details of
insulation and air-tightness to make it work properly - and most
builders aren't experienced in this yet.

Heat recovery ventilation is mandatory of you want to get by on
sunlight. Otherwise the actual ventilation needs render insualtion
ineffective.


Also triple glaze and use insulation over windows at might as well -
curtains or shutters.

Need plenty of thermal mass inside the insulation to keep warm at night too.

Stewart wrote:
Jim, he has already been advised that he will need air conditioning in the
summer because of the amount and quality of the insulation - solar panels
should operate this.


He doesn't. What he does need is shade from midsummer sunlight -
overhanging eaves, and mass inside the insulation. Then open windows at
night when its cool, and seal up and shutter/curtain down by day.

works a treat here.

Mr Sandman wrote:

It sounds like you can get useful heat from that size of lake, i have
just installed a GSHP on my place which is 170sqm of floor space. Its a
2kw/12kw Heat Pump, but we use 600m of ground loop, some of it in a well.

600m seems a lot. Is that the normal sort of length for a ground loop
and (without the well) how much land would be needed?

Roger Chapman wrote:
Mr Sandman wrote:

It sounds like you can get useful heat from that size of lake, i have
just installed a GSHP on my place which is 170sqm of floor space. Its
a 2kw/12kw Heat Pump, but we use 600m of ground loop, some of it in a
well.

600m seems a lot. Is that the normal sort of length for a ground loop
and (without the well) how much land would be needed?

We have the same size of collector - 6 x 100m pipes,
in 3 trenches - comes back to a pair of manifolds (one flow & one return
so individual loops can be isolated if required...

Adrian

Roger Chapman wrote:
Mr Sandman wrote:

It sounds like you can get useful heat from that size of lake, i have
just installed a GSHP on my place which is 170sqm of floor space. Its
a 2kw/12kw Heat Pump, but we use 600m of ground loop, some of it in a
well.

600m seems a lot. Is that the normal sort of length for a ground loop
and (without the well) how much land would be needed?

a lot depends on the soil. dry sandy is crap, wet soggy clay is very
good. I was quoted 200-400m in clay, no loop within 2 meters of any
other, for 12kw peak.

so 400 square meters minimum, for me, 800 squares better.

If you don't mind me asking, how have your gas / electric bills
varied since it was fitted ?
I'll see if I can find out - haven't actually done the sums...
but if I can find the bills then I'll let you know

Cheers - might also be worth putting in the wiki to give others
an idea about real-world installations, rather than a salesmans'
"in a perfect world" figures...

The Natural Philosopher wrote:

Mr Sandman wrote:

It sounds like you can get useful heat from that size of lake, i have
just installed a GSHP on my place which is 170sqm of floor space.
Its a 2kw/12kw Heat Pump, but we use 600m of ground loop, some of it
in a well.

600m seems a lot. Is that the normal sort of length for a ground loop
and (without the well) how much land would be needed?

a lot depends on the soil. dry sandy is crap, wet soggy clay is very
good. I was quoted 200-400m in clay, no loop within 2 meters of any
other, for 12kw peak.

so 400 square meters minimum, for me, 800 squares better.

0.1 to 0.2 of an acre seems to give me a better idea of the size. Should
fit in some (but by no means all) back gardens but installation would
make a complete mess of said garden even if it is practicable to dig the
trenches at 2 metre centres. If I ever get round to it I might consider
the adjacent field instead but that could bring its own problems.

Adrian Brentnall wrote:

Mr Sandman wrote:

It sounds like you can get useful heat from that size of lake, i have
just installed a GSHP on my place which is 170sqm of floor space.
Its a 2kw/12kw Heat Pump, but we use 600m of ground loop, some of it
in a well.

600m seems a lot. Is that the normal sort of length for a ground loop
and (without the well) how much land would be needed?

We have the same size of collector - 6 x 100m pipes,
in 3 trenches - comes back to a pair of manifolds (one flow & one return
so individual loops can be isolated if required...

TNT's advice was that pipes should be at least 2m apart so did your
installer dig 2m wide trenches or work to a lower limit?

In message , Roger Chapman
writes
The Natural Philosopher wrote:

Mr Sandman wrote:

It sounds like you can get useful heat from that size of lake, i
have just installed a GSHP on my place which is 170sqm of floor
space. Its a 2kw/12kw Heat Pump, but we use 600m of ground loop,
some of it in a well.

600m seems a lot. Is that the normal sort of length for a ground
loop and (without the well) how much land would be needed?
a lot depends on the soil. dry sandy is crap, wet soggy clay is very
good. I was quoted 200-400m in clay, no loop within 2 meters of any
other, for 12kw peak.
so 400 square meters minimum, for me, 800 squares better.

0.1 to 0.2 of an acre seems to give me a better idea of the size.
Should fit in some (but by no means all) back gardens but installation
would make a complete mess of said garden even if it is practicable to
dig the trenches at 2 metre centres. If I ever get round to it I might
consider the adjacent field instead but that could bring its own problems.

If I ever get round to GSHP using buried pipe I will try to *mole* it in
rather than trench. Subsoils here are clays and gravel and I have pulled
50m lengths of blue poly for water supplies without problems. I like the
manifold idea as pulling loops with more than two legs would be
difficult. Luckily the *moles* will fill with water so there is no lack
of contact.

regards

--
Tim Lamb

Roger Chapman wrote:
Adrian Brentnall wrote:

Mr Sandman wrote:

It sounds like you can get useful heat from that size of lake, i
have just installed a GSHP on my place which is 170sqm of floor
space. Its a 2kw/12kw Heat Pump, but we use 600m of ground loop,
some of it in a well.

600m seems a lot. Is that the normal sort of length for a ground loop
and (without the well) how much land would be needed?

We have the same size of collector - 6 x 100m pipes,
in 3 trenches - comes back to a pair of manifolds (one flow & one
return so individual loops can be isolated if required...

TNT's advice was that pipes should be at least 2m apart so did your
installer dig 2m wide trenches or work to a lower limit?

It was a few years back......
but I'm fairly sure that the trenches were about that wide
- big bucket on the digger! Can't really remember the layout of the
pipes in each trench - they were laid flat not 'slinky' style

Can't find a photo that shows the tranches - but definitely 6 loops x
100m each

Actual depth of the pipes varies -probably 5 - 8 ft depending on the
slope of the land...

Roger Chapman wrote:
The Natural Philosopher wrote:

Mr Sandman wrote:

It sounds like you can get useful heat from that size of lake, i
have just installed a GSHP on my place which is 170sqm of floor
space. Its a 2kw/12kw Heat Pump, but we use 600m of ground loop,
some of it in a well.

600m seems a lot. Is that the normal sort of length for a ground loop
and (without the well) how much land would be needed?

a lot depends on the soil. dry sandy is crap, wet soggy clay is very
good. I was quoted 200-400m in clay, no loop within 2 meters of any
other, for 12kw peak.

so 400 square meters minimum, for me, 800 squares better.

0.1 to 0.2 of an acre seems to give me a better idea of the size. Should
fit in some (but by no means all) back gardens but installation would
make a complete mess of said garden even if it is practicable to dig the
trenches at 2 metre centres. If I ever get round to it I might consider
the adjacent field instead but that could bring its own problems.

Best done at the 'building / earthworks' stage.
We had an area that dipped away sharply - and we wanted it to end up
level so's we could put a big polytunnel on it.

Wet soil ? - we're in Ireland - not a problem!
In fact, for much of the winter months (and last summer!) the adjacent
stream makes its way down to the road via our garden & collector loops.
Most of the time it's underground - sometimes it just flows on the
surface. No shortage of water here g

Given that the average air temp in the UK appears similar to the ground temp
how much extra does a GSHP save over an ASHP? I was toying with the idea but
I would need a bore hole for a GSHP and they are not cheap. Also as the heat
for the GSHP is actually solar there must be a problem replacing the heat in
the bore hole if the neighbours also decide to drill them, there isn't
enough land in the cities to absorbed the solar radiation needed.

I wonder if BT or the cable co would notice if I pulled my collectors along
their ducts?

On Feb 2, 12:56 pm, "dennis@home"
wrote:
Given that the average air temp in the UK appears similar to the ground temp
how much extra does a GSHP save over an ASHP? I was toying with the idea but
I would need a bore hole for a GSHP and they are not cheap. Also as the heat
for the GSHP is actually solar there must be a problem replacing the heat in
the bore hole if the neighbours also decide to drill them, there isn't
enough land in the cities to absorbed the solar radiation needed.


so are you saying the deeper you drill the colder it gets?

JimK

Tim Lamb wrote:

snip

600m seems a lot. Is that the normal sort of length for a ground
loop and (without the well) how much land would be needed?
a lot depends on the soil. dry sandy is crap, wet soggy clay is very
good. I was quoted 200-400m in clay, no loop within 2 meters of any
other, for 12kw peak.
so 400 square meters minimum, for me, 800 squares better.

0.1 to 0.2 of an acre seems to give me a better idea of the size.
Should fit in some (but by no means all) back gardens but installation
would make a complete mess of said garden even if it is practicable to
dig the trenches at 2 metre centres. If I ever get round to it I might
consider the adjacent field instead but that could bring its own
problems.

If I ever get round to GSHP using buried pipe I will try to *mole* it in
rather than trench. Subsoils here are clays and gravel and I have pulled
50m lengths of blue poly for water supplies without problems. I like the
manifold idea as pulling loops with more than two legs would be
difficult. Luckily the *moles* will fill with water so there is no lack
of contact.

IIRC moles can't get down to the sort of depth really needed for heat
pumping but I would be glad to be proved wrong even though the back lift
on my neighbours tractor doesn't work properly so I would have to hire
the equipment to do it.

On a connected topic there is a particular form of plough used to make a
form of land drain. Can anyone tell me what it is called please. We have
a very boggy hollow that really needs draining presumably because the
land drain has collapsed. I can't find the actually drain but even if I
could I lack the resolve to dig out and rebuild what might be as much as
100 yards of drain having spent a couple of weeks last Autumn on a
section less than 15 yards long.

JimK wrote:
On Feb 2, 12:56 pm, "dennis@home"
wrote:
Given that the average air temp in the UK appears similar to the ground temp
how much extra does a GSHP save over an ASHP? I was toying with the idea but
I would need a bore hole for a GSHP and they are not cheap. Also as the heat
for the GSHP is actually solar there must be a problem replacing the heat in
the bore hole if the neighbours also decide to drill them, there isn't
enough land in the cities to absorbed the solar radiation needed.

Ground temperatures are much more even than air temperatures and the
deeper you go the more constant the temperature.

so are you saying the deeper you drill the colder it gets?

The deeper you go the warmer it gets but ISTR TNT saying here quite
recently that the major source of near surface heating is solar.

On Feb 2, 4:14 pm, Roger Chapman wrote:
Tim Lamb wrote:

snip



600m seems a lot. Is that the normal sort of length for a ground
loop and (without the well) how much land would be needed?
a lot depends on the soil. dry sandy is crap, wet soggy clay is very
good. I was quoted 200-400m in clay, no loop within 2 meters of any
other, for 12kw peak.
so 400 square meters minimum, for me, 800 squares better.

0.1 to 0.2 of an acre seems to give me a better idea of the size.
Should fit in some (but by no means all) back gardens but installation
would make a complete mess of said garden even if it is practicable to
dig the trenches at 2 metre centres. If I ever get round to it I might
consider the adjacent field instead but that could bring its own
problems.

If I ever get round to GSHP using buried pipe I will try to *mole* it in
rather than trench. Subsoils here are clays and gravel and I have pulled
50m lengths of blue poly for water supplies without problems. I like the
manifold idea as pulling loops with more than two legs would be
difficult. Luckily the *moles* will fill with water so there is no lack
of contact.

IIRC moles can't get down to the sort of depth really needed for heat
pumping but I would be glad to be proved wrong even though the back lift
on my neighbours tractor doesn't work properly so I would have to hire
the equipment to do it.

On a connected topic there is a particular form of plough used to make a
form of land drain. Can anyone tell me what it is called please. We have
a very boggy hollow that really needs draining presumably because the
land drain has collapsed. I can't find the actually drain but even if I
could I lack the resolve to dig out and rebuild what might be as much as
100 yards of drain having spent a couple of weeks last Autumn on a
section less than 15 yards long.

are you trying to actually create a drain with this plough? or break
up the so called "pan" between subsoil and topsoil with a "subsoiler"
plough?

Cheers
Jim

"dennis@home" wrote in message
...

... Also as the heat for the GSHP is actually solar there must be a
problem replacing the heat in the bore hole if the neighbours also decide
to drill them, there isn't enough land in the cities to absorbed the solar
radiation needed.


You're in good company with that sort of misconception. Darwin went to his
grave struggling to reconcile his calculations for the age of the earth
based on his theory of evolution with those of Fahrenheit (IIRC although it
could well have been Kelvin, history was never my strong point) who
calculated how hot the earth should be given that the only source of heat
was the sun. Of course that was before anyone knew about radioactivity.

In the case of GSHPs you're operating at a much smaller scale so you can't
really consider the system as closed. Effectively you're sucking heat out
of the earth but as there's an awful lot there in the first place you can
consider it nearly infinite. That said, I did read recently about some town
scale GSHP schemes (Southampton springs to mind) which will need to consider
the cooling effect they will have on the ground as it will make their
schemes less efficient over the decades.

Tim Lamb wrote:
In message , Roger Chapman
writes
The Natural Philosopher wrote:

Mr Sandman wrote:

It sounds like you can get useful heat from that size of lake, i
have just installed a GSHP on my place which is 170sqm of floor
space. Its a 2kw/12kw Heat Pump, but we use 600m of ground loop,
some of it in a well.

600m seems a lot. Is that the normal sort of length for a ground
loop and (without the well) how much land would be needed?
a lot depends on the soil. dry sandy is crap, wet soggy clay is very
good. I was quoted 200-400m in clay, no loop within 2 meters of any
other, for 12kw peak.
so 400 square meters minimum, for me, 800 squares better.

0.1 to 0.2 of an acre seems to give me a better idea of the size.
Should fit in some (but by no means all) back gardens but installation
would make a complete mess of said garden even if it is practicable to
dig the trenches at 2 metre centres. If I ever get round to it I might
consider the adjacent field instead but that could bring its own
problems.

If I ever get round to GSHP using buried pipe I will try to *mole* it in
rather than trench. Subsoils here are clays and gravel and I have pulled
50m lengths of blue poly for water supplies without problems. I like the
manifold idea as pulling loops with more than two legs would be
difficult. Luckily the *moles* will fill with water so there is no lack
of contact.


you hope. here they use moles to drain fields ;-)

regards