My house is built on 26 screw piles. I was just chatting with my piles designer and he mentioned a new product he is offering:  piping for a ground-source heat pump (GSHP) built-in to the screw piles used for a foundation.

 

I thought it was be a nice solution. If you're planning to build a screw-piled raft foundation, you an add in GSHP loops for a low marginal extra cost.

 

He is based in East Anglia. https://www.enviga.co.uk

37 minutes ago, Dreadnaught said:

My house is built on 26 screw piles. I was just chatting with my piles designer and he mentioned a new product he is offering:  piping for a ground-source heat pump (GSHP) built-in to the screw piles used for a foundation.

 

They have "Geothermal" in their title, how deep are those piles going? Surely typical piles for housing would require there to be ground water flowing beneath the building, within the depth of the piles, as there won't be any direct "solar gain" or geothermal heat transfer.

There's not much info on the site linked, do they have any technical info available online? 

Edited February 19, 20251 yr by IanR

@IanR, he sent me a PDF on it. If you're interested I am sure he'd send it to you too. There is an enquiry form on the (pretty minimalist) website.

Boreholes need to be quite far apart too, so sounds a little too good to be true tbh.

 

@Dreadnaught, can you post the pdf if possible? 

If you work on 20 W.m^-1 of borehole depth and 2500 hours extraction per year, how do the numbers look.

 

(I seem to remember that this has come up before @Onoff asked me something about it a while back)

I'm too much of a sceptic to be cheeky enough to ask to be sent a copy.

 

What kind of ground do you have and where is the water table?

 

On clay it seldom works economically, 40m deep isn't unknown.*

On sand you've a chance due to water change.

On Norwegian rock it can be a bit different.

* I helped some people get the GS turned off and changed to air source. It was costing them thousands p.a. 

Here is the PDF for those interested …

 

Enviga Thermo Screw Pile™ Flyer (2025).pdf

39 minutes ago, Dreadnaught said:

Here is the PDF for those interested …

So no technical information what so ever.

Best to forget all about it.

 

 

38 minutes ago, Dreadnaught said:

Here is the PDF

Thanks. Interesting. Very believable for the less sceptical ( and experienced).

 

Storing solar energy in the ground will help but not in the winter. 

I don't want a legal battle so I will say nothing more about the claims made.

 

Is there another page with conditions and limitation? About the ground suitability, and any guarantees on performance and how this is guaranteed?

 

Just now, saveasteading said:

Is there another page with conditions and limitation? About the ground suitability, and any guarantees on performance and how this is guaranteed?

 

No, that's all I have. Would suggest contacting them for more information. I have no link to the product. Just thought it might be interesting for some. I'd consider using it if I was doing another build with a raft foundation on screw piles.

17 minutes ago, saveasteading said:

Storing solar energy in the ground will help but not in the winter. 

Any ground water movement will soon sap all the energy out of the ground.

5 minutes ago, Dreadnaught said:

I'd consider using it if I was doing another build with a raft foundation on screw piles.

I wouldn't.

I could say more but can't get too specific.

Sufficient to say that I studied the subject closely, got close to some experts, and would only consider it in very special circumstances.

Perhaps 15 years ago there were dozens of companies doing it, subsidused by government grants, ....and then there weren't.

There were some very professional companies who refused to do inappropriate projects,  and they lost their business through no fault of their own.

 

Air source meanwhile flourishes. That is because the air is exchanged for fresh and warmer air continuously whereas the ground gets colder, even freezes, unless flowing water replenishes the heat or heat is pumped in....all year.

 

If you can get a price and any technical info it would be interesting and a service to the community.

@Dreadnaught

 

Have you created an energy analysis yet?

 

If you have extremely low energy usage, then that will change the type of technology you use.

1 minute ago, SteamyTea said:

Any ground water movement will soon sap all the energy out of the ground

Ground water movement would provide some fresh energy resource so might make it feasible.

Ahh I see what you mean....you can't have both as a benefit.