Under Floor and Geothermal

whitelightrider

Right folks, Im in need of advice. We are just looking at the heating for a new build and we are putting in UFH upstairs and downstairs with heated towel rails in the bathrooms. Someone mentioned Geothermal, our plumber isnt mad about it. We just sank a well on the site and there is about 20ft of solid rock underneath the house. The Geothermal that was mentioned to us was the type thats bored instead of the looped kind. But with that amount of rock under the site is it really gona work?

whitelightrider

Anybody know about this? Spoke to one of the guys in Systemlink who said that rock is probably the best when using the Bored Geothermal.

smooth operater

I would consider heating upstairs with radiators instead, as for downstairs, yes go with the underfloor heating.
As regards the rock issue, i haven't a clue, i think i read somewhere that horizontal boreholes would have a better c.o.p., not sure how true that is though. Im sure someone else will be along soon to clarify

danyosan

smooth operater wrote: »

I would consider heating upstairs with radiators instead, as for downstairs, yes go with the underfloor heating.
As regards the rock issue, i haven't a clue, i think i read somewhere that horizontal boreholes would have a better c.o.p., not sure how true that is though. Im sure someone else will be along soon to clarify

Nope other way round mate, vertical is better COP.

The fact you have rock close to the surface is a good thing, it'll mean you won't need as much steel casing to keep the hole from caving in on itself.

sinnerboy

smooth operater wrote: »

I would consider heating upstairs with radiators instead, as for downstairs, yes go with the underfloor heating.
As regards the rock issue, i haven't a clue, i think i read somewhere that horizontal boreholes would have a better c.o.p., not sure how true that is though. Im sure someone else will be along soon to clarify

rads upstairs will need to oversized to run at low temp . may or may not be an issue .......

you will MOST LIKELY need 3 phase ESB supply twin tarrif meter . apply ASAP ESB can be slow ........

ardara1

I hear the AECB in UK have called for GROUND SOURCE HEAT PUMPS to lose their 'renewable' label and to stop any grant aids for their installation.
(Association of Environmentally Conscious Builders - or the Sustainable Building Association)

'Widespread COPs of less than 2.0 - people installing a system that cost 3 or 4 times the cost and emits more CO2 than the gas boiler it replaces'

Not encouraging!

yop

sinnerboy wrote: »

rads upstairs will need to oversized to run at low temp . may or may not be an issue .......

you will MOST LIKELY need 3 phase ESB supply twin tarrif meter . apply ASAP ESB can be slow ........

3 phase supply for a heat pump is it? Not at all if thats what you mean, standard supply is sufficent, you will be asked to specify your load usage when applying but definately not a 3 phase.

You can use the Solo rads upstairs but dont use normal rad with your heatpump as this will cost you a fortune, use UFH both up and downstairs if you can, keep the loops as tight as possible there fore given bigger heat coverage, lower running temps and savings on your running costs.

Just Learning

yop wrote: »

3 phase supply for a heat pump is it? Not at all if thats what you mean, standard supply is sufficent, you will be asked to specify your load usage when applying but definately not a 3 phase.

You can use the Solo rads upstairs but dont use normal rad with your heatpump as this will cost you a fortune, use UFH both up and downstairs if you can, keep the loops as tight as possible there fore given bigger heat coverage, lower running temps and savings on your running costs.

I am just looking at putting this system in a listed building refurb. The bad news is that you do need 3 phase electricity, if you have above average size house. I have been reading the threads and people are talking about 18 to 20K for the geothermal. I have 5k sq ft and have been quoted 75k for geothermal and underfloor heating throughout the house. Where are you guys getting these quotes from, I want to know?? Oh and the more rock you have to drill through the better - perfect for geo-thermal.

Just Learning

The house I am refurbing is built on granite and the two geothermal companies have said it is the best thing as when you put the rods in they are protected all the way down and supported by the rock. I am not surprised your plumber is not mad about it because you need a specialist to put it in and they do all the plumbing and installation, not something I would think about asking the plumber to install.

yop

Just Learning wrote: »

I am just looking at putting this system in a listed building refurb. The bad news is that you do need 3 phase electricity, if you have above average size house. I have been reading the threads and people are talking about 18 to 20K for the geothermal. I have 5k sq ft and have been quoted 75k for geothermal and underfloor heating throughout the house. Where are you guys getting these quotes from, I want to know?? Oh and the more rock you have to drill through the better - perfect for geo-thermal.

Well if you are dealing with a 5k sq ft house then you are not really talking normal alright

We paid 17k for 2100 sq ft house for geo and ufh both upstairs and downstairs. 75k is some price

Just Learning

Your right 75K is a lot! Is the price dependant on the type of pump you get, the equipment, how far you drill down, or just what the company want for doing it? Do you mind me asking you who you used to put yours in?

sinnerboy

yop wrote: »

3 phase supply for a heat pump is it? Not at all if thats what you mean,

In my experience with heat pumps, which I admit is limited and recently acquired - 3 phase is required .

I also note that the standard ESB application form has a dedicated section for heat pumps anticipating 3 phase + night rate taffif / twin metering .

ESB can be SLOW to deliver so any one thinking heat pumps needs to establish this EARLY ON in the build

yop

sinnerboy wrote: »

In my experience with heat pumps, which I admit is limited and recently acquired - 3 phase is required .

I also note that the standard ESB application form has a dedicated section for heat pumps anticipating 3 phase + night rate taffif / twin metering .

ESB can be SLOW to deliver so any one thinking heat pumps needs to establish this EARLY ON in the build

Must be a recent thing as we dont have 3 phase or does any of about maybe 10 people who I know put in heatpumps. Me thinks that some is fooling someone, I presume it is dearer to get in 3 phase and dearer to run it? ESB making soft money?

Goreme

You could always try an Air to Water heat pump. Also, with the heated towel rails in the bathroom - this can be problematic when there is an individual thermostat in the bathrooms themselves. The towel rails are enought to heat the rooms, therby turning off the water circulating in the underfloor. Result, a warm bathroom, but a cold floor!

bauderline

If you have a look at the specs for the popular heat pump systems available anything that has an output above 17kw seems to require a 3 phase supply. Kensa do a 20kw pump that uses single phase and it costs around 11k sterling.

Don't get ripped off for UFH, its a fairly simple system and the pipe is not that expensive, try a google for 300m pex. All you need is a manifold on each floor to run the pipes from each room back to. Rooms greater than 25m2 will need a second run. Put down your insulation, insulate around the edges, put down the clips for the UFH, lay the pipe starting at the manifold, running through the clips at 200 or 250mm spacings, no sharp bends nice curves, and then back to your manifold again.

Once you have all hooked up pressure test thoroughly for 24 hours to check for leaks before you even think about putting screed down...

75k ? Divide by two and then round down to the nearest 10k and you are in realistic territory.....

I picked up a good document at the weakend that illustrates the layour of UFH rather well, I will pull it off the pen drive later and post it..

b.

bertie1

I have a 3000sq ft house & put under floor in ( bungalow)
The drawings were sent to Quality Plastics who came back with detailed runs for each zone . Thermostat in each room , 2 manifolds, actuator pipe & tracks came in at €5000.00

We added towel rails ( which bypass the under floor temperature control)
Boilder ( condensing keroscene ) €2200.00 + vat

After that is was just the plumbers time , ware for the ensuites , & water storage tanks in the attic space

Solar panels & dual coil 450 ltr tank ( stainless becuase copper corrodes where we live €6000.00

In total €20000.00 covered everything . 1 bathroom , 4 ensuites with pumped showers

75K for geothermal is an awful lot of oil even at todays prices.
The running cost of the geothermal will be about 1/3 of the oil consumption price

yop

If you 1/2 them gaps on the UFH you will reduce your running costs big time and get wider heat coverage. I put ours in at max 100mm, it was tricking on the bends but patience is the thing

bauderline

Tip top document explaining the issues around Heat Pump electricity supply requirements and single / three phase supply...

http://www.kensaengineering.com/pdf/faq/Fact_Sheet_-_Power_Supplies_For_Kensa_Compact_Heat_Pumps.pdf

b.

bauderline

The two documents below give a good idea on how UFH should be layed out and also provide some useful information on how it should be installed and brought online for the first time....

HTH... Baud.

Edit : The second pdf is too big to attach, so here is the link....

http://www.underfloorheatingsystems.co.uk/pdf/UHS_One_Large_Zone_23_5_2007.pdf

sinnerboy

ardara1 wrote: »

I hear the AECB in UK have called for GROUND SOURCE HEAT PUMPS to lose their 'renewable' label and to stop any grant aids for their installation.
(Association of Environmentally Conscious Builders - or the Sustainable Building Association)

'Widespread COPs of less than 2.0 - people installing a system that cost 3 or 4 times the cost and emits more CO2 than the gas boiler it replaces'

Not encouraging!

AFAIK - please correct me if wrong

this is the only independent heat pump test centre in Europe

they test about 25 heat pumps annually - results can be downloaded here

Heat Pump Test Center WPZ
University of Applied Sciences NTB
Werdenbergstr. 4
CH-9470 Buchs
Phone: +41 (81) 755 33 55
FAX: +41 (81) 755 34 40

http://www.ntb.ch/3896.html

Wobs

sinnerboy wrote: »

AFAIK - please correct me if wrong

this is the only independent heat pump test centre in Europe

they test about 25 heat pumps annually - results can be downloaded here

Heat Pump Test Center WPZ
University of Applied Sciences NTB
Werdenbergstr. 4
CH-9470 Buchs
Phone: +41 (81) 755 33 55
FAX: +41 (81) 755 34 40

http://www.ntb.ch/3896.html

There is a place called Arsenal Research, think they are in Austria, they also test heat pumps.


Bauderline, that would be a bad design layout of UFH to run with a heat pump. As you can see it says it is designed to run at 45-55 degrees, heat pump are more efficient at lower temperatures. One of the reasons a lot of people are getting high running cost from their heat pumps can be down to a badly designed UFH system.

bauderline

Wobs,

Are you talking about the pdf I posted ? Can you please explain WHY that would be a bad design ?

How would you layout the pipes differently ? And I would not suggest that you run them at 55 either....

Wobs

I was talking about the installation guide you posted.

They talk about spacings of 200-300mm and loops of over 100m long.

Spacings should be 100mm, definetly no more than 150mm and the loops should really be no longer than about 80m.

Also coming into to a room and simply going up and down from one end to the other and coming straight back out is not the best way to do it. You need to be coming back the same way, either in a circular pattern or back between the up and down pattern. This will give you a more even distribution of heat.

bauderline

Wobs,

Not doubting you, but that flies in the face of a lot of the documentation I have read. The above system appears to be a fairly common practice install, which you appear to be saying is in fact bad practice.

I will hold my hand up and say I am no expert, I just go by the information I manage to find.

Can you outline your experience in this area ? Maybe your worth mining for further information....

yop

bauderline wrote: »

Wobs,

Not doubting you, but that flies in the face of a lot of the documentation I have read. The above system appears to be a fairly common practice install, which you appear to be saying is in fact bad practice.

I will hold my hand up and say I am no expert, I just go by the information I manage to find.

Can you outline your experience in this area ? Maybe your worth mining for further information....

Most of them are designed to run around 45-50 degrees which is common practice, not saying that is right

As I have said above you can achieve a much lower running temp with narrow loops.
We have a water flow temp of 28 degrees since our loops are so close together = Save Euro

leprechaun1916

Hi there

I, like so many people on here ,am stressing over which form of heating to use for my new build.

I was wondering how much does the Heat pump cost\? ( I appreciate it will vary in accordance with the size of the house etc) but as a percentage of the cost of installation.

Lots of people are claiming that the heat pump will have paid for itself in at most 20 years, however have they factored in maintenance costs and worst case scenario ,a replacement heat pump?

Id be extremely interested in hearing peoples own experiences with Geo Thermal ,Solar and any other forms of heating, with respect to a new build. I'm looking for some form which will save money and if I can help the environment,great!