Ground source heat pumps

[Silinman]

We are thinking of self-build next time around, and being mindful of the current environmental problems, we like the idea of installing a ground source heat pump.

Question for all you pro installers out there and anyone who has gone down this route, any general advice or tips? I understand that to gain maximum benefit the system should be used with under floor heating.

Is ground loop better than vertical bore hole? Do they provide enough heat, or must other heating be installed?

Any tips or advice would be very welcome.

TIA

Silinman

 

[doitall]

For ground source you need an area of shade free ground approximately twice the size the footprint of the property.

Bore holes are good provided you can get approval from the water Company, and tap into a good water course.

A large pond/lake is the best

 

[senator3litre]

I have no knowledge of the installation of these systems, just their use. My sister lives in Devon, and has one of these systems fitted in her cottage.

The only advice I can give you concerns noise. The pump and associated plant for my sisters system is in the kitchen. Be warned these systems can be quite noisy, especially when they start up. In the kitchen, its not such a problem, but you wouldn't want the equipment near your lounge or bedrooms. See if the equipment can go in an outbuilding, etc.

Its just one thing to consider at the planning stage.

 

[Biggles..]

Heat provision without Aux heating is between 35 and 42 degC on most current domestic units so combined with UFH it works a treat.Rads its not so clever.

All work via weather comp so your getting the best control to performance available individual controlled zones creates its own problems cos the heat pump alone isnt designed to operate that way.

Equipment is large and with associated parts,brine filters coneections,vessels and possable buffers space is required.

Loop size on the last few we've done all come back around 200m for an average 3/4 bedroom barn conversion.trench depth 1m and pip layed at 750-1000mm apart.It does start to cover a large area.

 

[doitall]

lcgs.

You can lat 32mm mdpe at 600mm centers, 1200 + deep without any problems.

The loops want to all be the same length for balancing, 100m rolls are ideal, and use a reverse return, if you use a manifold

 

[fitz1]

Dont forget your using electricity to run it and with the install its probably cheaper to fit and run gas condensing boiler.

 

[Biggles..]

Dont forget your using electricity to run it and with the install its probably cheaper to fit and run gas condensing boiler.

Most have COP of 4.whatever.

Electric usage is minimal unless using the aux heat settings.

At present Danfos are supply and fit of their unit for 3K all you have to do is the internals and the loop,they'll do the rest. Its a good offer cos their trying to break into the market,their kit is of a company they've just aquired that have been in the game for years.

Nebe units are good bits of kit but come at a price.

John- each manufacturer is different but all the ones we've done recommend as standard HDPE not MDPE and all with pipe sizes not smaller than 40mm.

 

[doitall]

That would account for the wider centers.

Don't you find the 40mm bumps the price up considerable over 32mm. ?

 

[Silinman]

Thanks everyone for your replies - I went to the self build centre in Swindon recently and got some good information, but I'm really interested in knowing if such a system can provide enough heat - i.e. similar to a typical CH system with wet rads and a boiler.

I've never been in a house with UFH so have no idea how warm they get. I guess the answer is to make sure the house is well insulated to start with. As we are self building, that is part of the overall plan to incorporate as much modern insulation material in the walls, floors and roof space.

 

[Biggles..]

Conventional radiator heating works around flow temps from boilers above 60deg c which you'll never get out of a GSHP without massive electric backup reducing the COP down to that of standard heating methods.

UFH gives the same heat effect throughout the home without the required heat form the boiler,generally UFH is blended down to aroun 40deg which from aGSHP is spot on,theres no need to blend the UFH manifolds because your getting the right temps.

UFH is a more comfortable and even heat in my opinion.

Expect 19-21deg average temp from a GSHP running UFH.Radiators will be cool to touch and will only give you the same temp range,so save your self the wall space and fit UFH if your still at the design stage.

 

[doitall]

Why anyone would want to fit radiators in a new built is mind boggling, absolutely no sense whatsoever.

We could get 55c from our heat pumps (Alpha Inatec) so oversized rads and you could get away with it.

 

[charliechaplinspants]

Not a genius but have been involved in the install of these, but it was for a block of apartments (flats we call`em) Very noisy, very prone to breakdown because they were installed in an outbuilding. Not hugely reliable in my opinion, but I`m not a Professional or anything. Loads of callbacks throughout the apartments, all had underfloor heating and unvented cylinders, great hot water. heating was a bummer.

 

[charliechaplinspants]

Heat provision without Aux heating is between 35 and 42 degC on most current domestic units so combined with UFH it works a treat.Rads its not so clever.

All work via weather comp so your getting the best control to performance available individual controlled zones creates its own problems cos the heat pump alone isnt designed to operate that way.

Equipment is large and with associated parts,brine filters coneections,vessels and possable buffers space is required.

Loop size on the last few we've done all come back around 200m for an average 3/4 bedroom barn conversion.trench depth 1m and pip layed at 750-1000mm apart.It does start to cover a large area.

Is anyone meant to understand this? If you Guy`s would like to help out mere mortals, can you forget trying to impress each other?

 

[Biggles..]

I thought you guys spoke english so re rereading what i put i dont actually get what you dont think is simple laymans terms apart from some awful spelling

but just in case Aux heat is electric immersion backup(refered to on the inbuilt menus as Aux)

and UFH is underfloor heating.

The units DIA used are fantastice but are more a commercial based product. current domestic marketed units dont get those figures due to the quality of the refridgerant used.

Radiators are normally oversized by 20% and up to allow for the differing performance figures.

 

[charliechaplinspants]

Sorry, it`s probably me. I was under the impression that you were inebriated.