Recommended depth of horizontal geo collector

rodge123

After a quick google it seems that a lot of people are recommending the horizontal piping be under 5 or 6 feet of soil.
I suspect this is for cooler climate where frost penetrates deeper?

What would be the recommended dept in Ireland?
Are there scenarios where it will increase or decrease?

rodge123

rodge123 wrote: »

After a quick google it seems that a lot of people are recommending the horizontal piping be under 5 or 6 feet of soil.
I suspect this is for cooler climate where frost penetrates deeper?

What would be the recommended dept in Ireland?
Are there scenarios where it will increase or decrease?

Anyone?

KCross

Im not an expert but my understanding is that it is soil conditions dependent but typically a metre in depth.
Going to deep is bad and going too shallow is bad.
So, there isnt a recommended depth for Ireland.... it depends on your site.

Calahonda52

did u ask these guys?
http://gsi.ie

as stated its site /aspect/ topography specific

without links, comments like this
it seems that a lot of people are recommending the horizontal piping be under 5 or 6 feet of soil.

smacks of " let someone else do the work, for free"

rodge123

Calahonda52 wrote: »

did u ask these guys?
http://gsi.ie

as stated its site /aspect/ topography specific

without links, comments like this
it seems that a lot of people are recommending the horizontal piping be under 5 or 6 feet of soil.

smacks of " let someone else do the work, for free"

No, I didn't ask those guys.

What's "Let someone else do the work, for free" meant to mean?

air

There isn't any disadavantage to going too deep that I'm aware of.
The deeper you go the closer the temperature gets to the annual average temperature of the area and he less it varies with the seasons.
Below about 8m or so there is virtually no seasonal variation.
Obviously it's a case of diminishing returns as it's more work to go deeper, I believe most people shoot for about 1m in depth in Ireland.
Deeper trenches are used in colder climates.

Calahonda52

air wrote: »

There isn't any disadavantage to going too deep that I'm aware of.
The deeper you go the closer the temperature gets to the annual average temperature of the area and he less it varies with the seasons.
Below about 8m or so there is virtually no seasonal variation.
Obviously it's a case of diminishing returns as it's more work to go deeper, I believe most people shoot for about 1m in depth in Ireland.
Deeper trenches are used in colder climates.

For Horizontal pipes I see this somewhat differently and maybe incorrectly but lets give it shot from the science perspective.

The heat extracted from the soil needs to be replenished from somewhere.

If the pipes are " closer" to the surface then there is some chance that solar gain will replenish the heat extracted.
If they are "deeper" then the replenishment source and rate of replenishment is less obvious so what may be required is a much longer run of pipe to stop the ground being chilled.

The kit needs to be sized properly from end to end, based on heat demand.

Averge soil physical conditions are important as well, especially wet vs dry.

There are examples around of horiz=ontal pipe systems not working after period due to the over chilling.

If I can find one will come back with it

rodge123 wrote: »

No, I didn't ask those guys.

What's "Let someone else do the work, for free" meant to mean?

It always helps if links are provided for actual searches done to save on duplication so any additional suggestions can be complimentary

air

Calahonda52 wrote: »

For Horizontal pipes I see this somewhat differently and maybe incorrectly but lets give it shot from the science perspective.

The heat extracted from the soil needs to be replenished from somewhere.

If the pipes are " closer" to the surface then there is some chance that solar gain will replenish the heat extracted.
If they are "deeper" then the replenishment source and rate of replenishment is less obvious so what may be required is a much longer run of pipe to stop the ground being chilled.

The kit needs to be sized properly from end to end, based on heat demand.

Averge soil physical conditions are important as well, especially wet vs dry.

There are examples around of horiz=ontal pipe systems not working after period due to the over chilling.

If I can find one will come back with it

You can certainly over chill the ground with an undersized loop no problem.
However in winter, the deeper the pipe the more energy is available to replenish the heat from all sides.
Fair enough in the spring & autumn you might do better with a shallow pipe but in the depths of winter when the pump will run most the deeper it is the better in general.

Calahonda52

air wrote: »

You can certainly over chill the ground with an undersized loop no problem.
However in winter, the deeper the pipe the more energy is available to replenish the heat from all sides.
Fair enough in the spring & autumn you might do better with a shallow pipe but in the depths of winter when the pump will run most the deeper it is the better in general.

Can't and wont argue with that, like u I just want to highlight the issue that chilling needs to be considered and that one size fits all is not a design approach.
I suppose, theoretically at least, if u go deep enough horizontally, cost wise vertical might become an option, with less surface area needed.

Must be a cost curve somewhere:D
Keep well

air

Yes you're spot on, I'd imagine someone has done the figures to come to the 1m guideline figure for cost benefit in the Irish climate.
A mole plow might even be feasible at that depth if you had really nice soil free of rocks.
On US forums I see guys putting pipe runs down 8ft minimum but obviously this is in areas with long cold winter seasons.