Geothermal and UFH Vs Oil and Rads

nophd08

Jrochey wrote: »

Thanks again great responses from everyone. Just wondering the guys who did install the geo is there any changes they would make if they were going back again. Also just wondering would it be a good idea to heat downstairs with a heat pump and maybe the upstairs with an alternative heat source or is it just better to heat the whole thing with the geo. Or is it a waste of time. I'm going to go with concrete floors upstairs still wondering about underfloor upstairs tho not sure bout it any ideas from anyone. All the people who have the geo have said its great loads of hot water etc and all u have to do is put in loads of insulation. I know that no system is bombproof but starting out i'd like to cover all the bases. Thanks lads great advice just trying to decide hard to pinpoint would it be better just to insulate the beejaysus out of the house or is that going overbord.

A lot of very good information from all other posts and the one thing that is common in all of them is... INSULATION. When your house is properly insulated then it wont be expensive to heat.
I know of one 2800sq ft house built 10yrs ago and he spent over 8k punts on the best insulation available at that time. UFH installed on both levels and a few rads on 3rd level attic type room. About 1200litres of oil per year give or take to heat house and all DHW.
I think laying all pipes for UFH and Geothermal is the way to go.

freddyuk

I am almost convinced. Can I ask capital cost for the HP ? How much pipe was laid and how? Deep bore or slinky. Size?

My concern is always that you have one way of heating water. Any break in supply or equipment failure you can't even get a decent shower and it will happen on a Friday night Bank holiday.
Also we do not control the supply so it may rise especially as it is government controlled.
No one controls the solar.... and never will. Always free once paid for.

RavenII

freddyuk wrote: »

I am almost convinced. Can I ask capital cost for the HP ? How much pipe was laid and how? Deep bore or slinky. Size?

My concern is always that you have one way of heating water. Any break in supply or equipment failure you can't even get a decent shower and it will happen on a Friday night Bank holiday.
Also we do not control the supply so it may rise especially as it is government controlled.
No one controls the solar.... and never will. Always free once paid for.

Wrong there...the heatpump heats the water (it runs hotter for a short period to do this on priority) but there's immersions in the cylinder (unused) as backup and there's also an electric in-line immersion in the Nibe heatpump, also unused...so we have three ways of heating water...as I said before I spend so little of the total heating hot water (and I like solar) it's not worth my while spending a few grand on panels to reduce the €175 - 200 I spend on HW

The heatpump itself was about €6500+ we used a 150M borehole which cost about €4000 to do. Also there's about another 100M of pipe from the energy well to the house which saved us from having to do a deeper or second bore. The plumber got about €2000...We got a grant of €6500 from SEAI, which has been cut down to €3500 now and is only for existing houses. I think they take the view that new building regs make either solar or a HP mandatory so they don't need to support it.

RavenII

Jrochey wrote: »

Thanks again great responses from everyone. Just wondering the guys who did install the geo is there any changes they would make if they were going back again. Also just wondering would it be a good idea to heat downstairs with a heat pump and maybe the upstairs with an alternative heat source or is it just better to heat the whole thing with the geo. Or is it a waste of time. I'm going to go with concrete floors upstairs still wondering about underfloor upstairs tho not sure bout it any ideas from anyone. All the people who have the geo have said its great loads of hot water etc and all u have to do is put in loads of insulation. I know that no system is bombproof but starting out i'd like to cover all the bases. Thanks lads great advice just trying to decide hard to pinpoint would it be better just to insulate the beejaysus out of the house or is that going overbord.

Just use the geothermal HP for either floor heating or rads - I have both at home and the Nibe heatpump controls both systems linked to the weather which is good for comfort and savings.

If you're doing a concrete upper floor just put the UFH pipes into the screed attached to the steel mesh. (probably cheaper than rads) There's no insulation used (its an internal leaf in the house) and no additional structural expense, but another bonus is that you can getthe heatpump to run a little harder on the night rate and store the cheap energy in that slab.

shummy38

selfbuiler wrote: »

Hi, I just recived planing for my one off dream home. I`m unsure should I go for Geothermal and underfloor heating OR should I go for just and oil burner and Radiators. PLEASE HELP........

You can also go for underfloor heating with Oil. However the best option is to go with Geothermal and UFH. Cost is the issue here, with no grants available for new build your cost will be an additgional 5-6K over the oil/rads alternative . For a 3000 sq ft house you should save the best part of 2000 Euros per year with a heat pump.

I would suggest you go for one of the models that includes a hot water tank built into the heat pump

For choices I find Polytherm heating systems very helpful www.polytherm.ie or talk to Peter Mulvihill in their renewable energy sister company www.origen.ie 01-4191990 they are all in the same office and they sell rads and boilers too so they have no axe to grind either way.
Best of luck.

RavenII

Back-pedal to post no. 27 I left yesterday hope its a help...PM me if you want the installer etc. The heatpump is a 12kW Nibe 1145 model from www.unipipe.ie

shummy38

selfbuiler wrote: »

Hi, I just recived planing for my one off dream home. I`m unsure should I go for Geothermal and underfloor heating OR should I go for just and oil burner and Radiators. PLEASE HELP........

Thanks for that.

Im new to Boards so just getting the hang of things.

freddyuk

RavenII wrote: »

Depends on what the floor heating is in...ours is just at the back of the wooden floors in only 20mm screed and in alluminium plates elsewhere...it heats up almost as quick as rads...I just leave it on because we're 'having our cake and eating it'...at €1600 a year for the heatpump; my sister spends more on gas in her 3-bed semi in Foxrock!

What is under the 20mm screed? The whole idea of underfloor is to heat up the screed which is 75mm thick with 200mm of insulation underneath so it acts as a heat emitter. Once it is up to temperature it will maintain that heat for a long time in a well insulated draft free room. Mine will drop maybe 2-3 c overnight without any additional heating when it is several degrees colder outside. (Tiled flooring)
If you have 20 mm screed then your pipes are touching the timber floor as the o/s diameter of 15mm pipes is 18mm or thereabouts. This is why you need the heating on all the time because it will cool down very quickly if your pipes are not in 50 - 75mm of screed depth.
Thinking this through i guess you have thick timber flooring? The screed - if laid on 200mm of insulation would not be stable enough without a heavy flooring however you are then using the timber as your heat emitter?

RavenII

freddyuk wrote: »

What is under the 20mm screed? The whole idea of underfloor is to heat up the screed which is 75mm thick with 200mm of insulation underneath so it acts as a heat emitter. Once it is up to temperature it will maintain that heat for a long time in a well insulated draft free room. Mine will drop maybe 2-3 c overnight without any additional heating when it is several degrees colder outside. (Tiled flooring)
If you have 20 mm screed then your pipes are touching the timber floor as the o/s diameter of 15mm pipes is 18mm or thereabouts. This is why you need the heating on all the time because it will cool down very quickly if your pipes are not in 50 - 75mm of screed depth.
Thinking this through i guess you have thick timber flooring? The screed - if laid on 200mm of insulation would not be stable enough without a heavy flooring however you are then using the timber as your heat emitter?

The 20/25mm screed around my pipes is non-structural - its sitting on insulation boards between the joists. The floors are of course nailed to the joist. The Alluminium plates carry out the exact same function...the response time is quicker, but the really nice thing is that our heatpump is linked to the weather, so the floors change temperature with demand rather than most UFH systems which are set for the worst day at 45deg and then rely solely on thermostats for control which is a bit rough. When its say 7 outside the UFH water is around 31 deg...if its -1 out it climbs to about 39, so the heatpump always gives a very high return (C.O.P.).

I do the opposite in the rear of house, there's UFH in 150mm concrete - that's about a 1/3 of the total floor area. I stick an extra couple of degrees into that on the off peak rate and it acts as a flywheel effect to the entire system.

franb7111

"any half decent heatpump will return 4 units of heat for every 1 unit input,"

Hi all,
I will be starting a new build and looking at heating methods. However i have heard/ seen the above statement and was wondering if some one could explain it. Surely if you put in 1 unit (of energy ?) and get out 4 units this would solve the worlds energy problems? As far as i remember the law of conservation of energy states that " energy can neither be created nor destroyed but changed from one form to another " (except possibly in the case of nuclear fusion/ fission). I am not trying to be a smart A$$, Is this taking into account the total input of electricity over the entire year, (i assume that in the summer v little electricty is used) v the total heat output. Also If this is so wouldn't a geothermal system be far better than an airpump system as the temp difference in the winter between the air temp and several meters under the earth would be quite large (>10oC)

Plombier

Keeping the explaination very simple, in a heatpump you have a working gas, lets call it a heat transfer medium which, when compressed its temperature rises, so very simplified you supply 1 KW electricity(for compression) and get one KW heat from the heat transfer medium (1 KW in 1 KW out obeys the law), next the heat transfer medium is expanded back to normal pressure where it obviously drops in temperature because heat was extracted at the compression stage, next with an air source heat pump the fans blow vast amounts of air across the heat transfer medium which raises its temperature (this is the free bit but still obeys the law) and the cycle continues giving approx 3KW heat for 1KW electricity.

franb7111

Thanks Plombier, I just left there and visited a fw sites and i understand now, all the heat pump is doing is moving energy from one place the (out side) to another (the inside). However as the temp drops in the winter the free heat from the outside gets less and less so would you be better having an alternative heat source for UFH such as a wood burner or something. Also is geothermal not a much better option than a Air source pump or is the cost of geothermal usually cost prohibitive. I am building a 300sqm house to nearly passive standards and will be installing a HRV. The site is on a south facing aspect, so i probably won't need much heating from may to oct. (there is a 100 year old cottage on the site at the moment that we are in, its a bit of a wind tunnel but afgain we didn't need heating from may to oct) So i am wondering if one would still get the same benefit from a (COP 0f 3 to 4) from a heat pump is the heat output was measured over the colder months and not over 12 months

RavenII

Hi FranB, I see Plombier has explained the difference between power and energy!.... if you're building a super air-tight passive type house you should just look at using a smaller heat-pump...maybe an 8kW output unit instead of the 12kW one I have... in the coldest weather, a ground source heatpump is still cheaper than anything else at the moment and likely to remain that way. From the manual on ours if we have 7deg coming in from the collector in the garden and 35deg in our floor heating we get 5.7 units heat from each kW to run it.

An air to water HP will still work at -5 but its output is reduced on those occasional nights; thats why you always use some sort of 'back-up' with them,regardless of manufacturer or type. Also mind you don't over-ventilate the house with the HRV - another option too is to take the waste air into the heat-pump's collector fluid which is very clever.

weston1

trying to research all the heating systems out there and finding it hard to nail down the right one. firstly my insulation will be priority 1. 4000sq ft house, still unsure with the geothermal, and only cause i just feel i dont know enough. i was leaning towards that with ufh. now came across another system, turboburn. its a furnace that burns timber, waste oils, kerosene, whatever you have. it heats a large tank of water within the furnace rapidly and then the water sits there until needed, i assume the stats tell it when that is so. now you have to feed the furnace as required but this may be only once/twice daily in winter, every 3 to 4 days in the summer. just wondering has anyone heard anything about them. the salesman swears by it, as you would expect, but he sells the idea well and has good knowledge of heating. he runs a hostel on this and loves it. he has access to timber and used oils. he also told me he has a windmill up and it was the greastest waste of money ever. the unit is a copy of what is used in alaska. here's a link. i am intrigued by it but........ http://turboburn.co.uk/

RavenII

You will heat your house and HW very cheaply from the heat-pump- they run at around 1/3 of the cost of oil (SEAI's latest energy figures give oil at 10c / kW - the heatpump costs about 3.5c kW Hr)...it's not worth messing about with buffer tanks etc.

Above copied from my earlier post ...If you have a well insulated 4000sq. ft. house use a 12kW heatpump (I have a 12kW Nibe 1145 Geothermal heatpump in a slightly smaller house but it's not so well insulated) - It'll only cost about €1200 to €1500 for all heating and HW annually, and that's just a little machine like a fridge in your utility room which runs automatically...the other thing looks like it will be more expensive, has to have a boiler house... however if you like stoking boilers three times a day and heating is your hobby...!

Chipboard

I knew nothing about geothermal heatpumps or ufh until around 24 hrs ago and probably don't know alot more now, so maybe some of you my have some comments on the following;

I'm considering the purchase of a house which is 1,900 sq ft in area, a detached bungalow on its own large (exposed) site. I'm told the house is A rated but will be getting my own BER done just in case the first was fiddled. Two of the four bedrooms and all the living space have the sun all day (loads of windows).

The house has a Fighter 1220 system and under floor heating. I was a bit afraid after seeing a few posts on boards.ie complaining of high ESB bills so I bought an Owl energy monitor today and hooked it up to the fuseboard in the house (I have access even though I haven't even placed a bid yet).

I know nothing about how these things operate but it seems to have three distinct cycles so I monitored the power consumption and length of each and it was as follows;

Cycle 1 0.460 kw/hr 16 minutes
Cycle 2 4.380 kw/hr 3 minutes
Cycle 3 0.203 kw/hr 2 minutes

The only other power in use was a 200 watt bulb (no idea why he has 200 watt bulbs in several of the rooms) so the above is net of that.

I calculated from the above that it runs on each cycle for the following percentage of the day;

Cycle 1 76%
Cycle 2 14%
Cycle 3 10%

I used this to calculate that it will probably consume the following power;

Cycle 1 76% of 24 hrs 18.2 hrs @ 0.460 kw/hr = 8.37 kw
Cycle 2 14% of 24 hrs 3.4 hrs @ 4.380 kw/hr = 14.9 kw
Cycle 3 10% of 24 hrs 2.4 hrs @ 0.203 kw/hr = 0.49 kw

Total power consumption over 24 hours = 23.8 kw

23.8 kw X 14.1c per kw = €3.36 + vat = €3.81 per day

As it was around -2 degrees all day today this wouldn't seem an excessive cost to have the entire house heated and hot water.

Obviously it will be far cheaper for most of the year. Also, I'm fairly sure that tweaking the settings will bring efficiencies as the current settings were input by the auctioneer a couple of days ago and he knows even less than me about the system. I reckon I could turn down the heat a degree or two and still be comfortable.

I've left the energy monitor connected and will go back tomorrow to check the consumption over the 24 hours. The fact that the house isn't occupied will probably have an effect but I don't think it would affect it too much as the Fighter 1220 manual said something about appliances giving off heat.

Is the above too simplistic or just plain wrong?

freddyuk

Funnily enough i just received my free energy monitor from EON in the UK which i hooked up to my supply in Ireland last week. Change the currency and reset the rate and it was monitoring our usage which does not include any hot water or heating (except the C/H pump) as I have split U/F and radiators run off an oil boiler.
It had us mesmerized all week.
It averagely ran at 400 - 800 kwh daytime and 300-400 night time unless we used the oven or put the kettle on. I saw it peak at about 5.5 kw when both ovens were on. Microwave also pushed it over the 1 kw as they run at 700 - 800 kw however that is all very temporary. We have a gas hob. The mystery 1kw output during the night was traced to my well pump heater! Other large items include freezer and large fridge / freezer. Electrics on standby and computers are really irrelevant in the overall scheme of things. So I reckon my average was around 10-12kw per day which tallies with my recent Airtricity bills.
As i am fitting solar PV and DHW and possibly an Air Heat pump i am getting the before and after readings. It can be logged into the computer and charts set up to monitor the readings but sadly not into a MAC.

So to compare your readings for hot water and heating you can reckon the above numbers can be added as "other" non heating power. Not sure if hot water is included in your readings but the KWH number is getting scary.
We have 2100 sq ft. bungalow. Definitely not 'A' rated so we will have issues with insulation.
(I can confirm those instant one cup kettles use more power to make a cup of tea than a normal electric kettle.)

Maybe this will assist you.

Has not meant my wife has any clearer idea about zoning unfortunately.:D

Chipboard

Currently use 12KW per day so I expect to use nearly that much in the new house however I'm not factoring that in to my sums as I am only trying to guage the incremental cost of using geothermal and under floor instead of oil - I'll have the 12 KW 'other electrical costs' regardless of what house I am in.

If I use €4 on heating (for round figures) on the coldest day of the year and €0 on the warmest and average it out at €2 I would end up with a total annual bill of €730 for heating which would be fine as we currently use around 2.5 X 1000 litres X .55c which equates to almost €1400 per year on oil. They're are probably more cold days than warm in Ireland so will call it €1,000.

Even if it was the same cost it would be worth it as the quality of the heat is fantastic. The house we're in now, most of the time you feel a bit cold and you get the odd feeling of warmth when you are close to a rad but in the one with geothermal you can't feel the heat it just feels really comfortable. I'd say it will make it alot easier to get out of bed in the morning.

freddyuk

U/F is much better heat as you have noticed. It needs handling differently.
Let us know what the readings are today so we can make a better judgement.

Also getting oil for 55c is a bargain!! Where from?

RavenII

(FreddyUK) Meter reading 'scary'???? ....heating your house and running your lights, fridge, freezer etc etc for €3.84...I fail to see the scary bit there!

I don't understand the 'three cycles' bit?...the heatpump just does water heating (higher temperature & slightly higher power consumption when it's doing that job) and then the floor heating or rads at a lower temp.

Latest figures from SEAI: -
Oil Burnt at 80% efficiency 10.37 cent per kW - The heatpump averages (night/day rate) about 3 to 3.5 c per kW delivered.

Chipboard

I don't know how that gizmo works Raven but it was definitely running three distinct power consumption rates during the hour or so I was there yesterday and at the end of the third it went back to the first (4th used exactly the same power as the first).

At any rate I left the energy monitor there over night.

The estimate in my post yesterday would have been fine had it panned out.

I went up and collected the energy monitor this evening at 7 o'clock this evening. Brutal result.

It used 56.74kw in the 26 hours which equates to 52.4kw over a 24 hour period. This is for heating alone as there is nothing else powered up in the house - it doesn't even have a burglar alarm.

In monetary terms this would convert to a cost of €8.34 for the 24 hours and as the house was empty that was without hot water use and people opening and closing the external doors thus reducing the heat retention of the house.

Coincidentally, the auctioneer rang me today and told me that the BER rating (advertised as A rated on Daft) which he assured me was genuine two days ago, hasn't actually been done at all yet (never met an auctioneer yet who could tell the truth). I'm sure it will come in at alot less than A rated when its done.

I'm aware that the current weather is harsh but this location has got away lighter than almost everywhere else. The temperature was -2 for most of yesterday and -2 to -4 today. It hasn't snowed and all roads are easily passable.

The above daily rate would convert to €250 for a month. As our two monthly ESB bills are usually €120 in our current oil heated house, this means we could expect a bill of €620 for Dec Jan in the house we're looking at. It shouldn't cost this much to heat any house in cold but not extreme weather.

freddyuk

I rest my case!! If the "converts" can really prove these units work efficiently then let's see the proper proof. I am researching hard for proof and i asked someone who actually has the means to measure the results with no "angle" and we find the results suddenly become disappointing.
I am not casting aspersions here but simply seeking the truth as 90% of what i have researched has been negative from an efficiency standpoint.

Plombier

You said the house was 1900 sq ft(180 m sq) if the house is not up to current building regulations then I suspect that using a figure of 75 watts per meter sq. might be about right for this excercise, 180 msq times 75 is 12.6 KW just for heating, 12.6 times 24 is 304.4 KWH because of the current weather the heating system is at design condition and will run continuiously as would oil or gas, you measured 52.4 KWH of electricity for a 24 hr period giving 304.4 KWH of heat thats a COP of 5.8 which is excellent. Oil (approx 10KW/ltr.)for the same period with a 90% efficient boiler 10KWH times 90% is 9KW/ltr. 33.8 ltrs. per 24hr at the wonderful price of 55 cent will cost 18.60 for the same period but at 75 cent its 25.35.

HP____Oil@ 55c____ Oil@ 75c
€8.34__ €18.60_____€25.35

The cycles you see are related to different parts of the heatpump, compressor, heating pump, brine pump etc.

Chipboard

It could well be down to the BER rating of the house. It's advertised as A rated and I was assured this was genuine but it later transpired that the BER hasn't been done.

I'll post up the BER in a few days when it's done.

It's a disgrace that auctioneers can blatantly lie when selling houses and buyers have no recourse. Another couple have a bid on this house and if they buy it they are going to be robbed with high heating bills.

RavenII

If nothing is powered up in the house, I presume it's un-occupied so why don't you just turn it down? (the dial on the front of it)

My cost meter in the same weather, but probably a bigger heatpump as we have 350sQ. M ran to €10.30 for the lat 24hrs, but I'm not worried because when the weather's milder it uses much less; our total for the last year was €1620.00 only...our house was mostly built in 1971, so the insulation of your A rated house will be a world away.

The machine in a 180Sq. M house will probably be well under €1000 annually, so I wouldn't worry about it, its still the cheapest way of heating a house in Ireland by a country mile.

RavenII

Should have also mentioned that if the house is un-occupied, there's simply no other normal sources of heat from TVs computers, people etc etc, so its an innacurate reflection of what to expect

Chipboard

RavenII wrote: »

My cost meter in the same weather, but probably a bigger heatpump as we have 350sQ. M ran to €10.30 for the lat 24hrs, but I'm not worried because when the weather's milder it uses much less; our total for the last year was €1620.00 only...our house was mostly built in 1971, so the insulation of your A rated house will be a world away.

Raven do you mind me asking how many kw's you used in that 24 hrs - just in case we're using different cost per kw.

I'd be amazed if I got away with €1,000 for the year as my two monnthly bill for Dec and Jan will be €500 for heating alone based on the usage I'm seeing in the last two days.

I went up there just now and checked the accuracy of the energy monitor I used by reading the ESB meter - the result was the same - 53 kw per day to run.

Plombier

It will cost three times more to heat the house with oil, all your figures add up.

heinbloed

A horrible result when it comes to the real world, the usual experience of HP based heating systems, most fail the promises which are used to sell them ....

Chipboard wrote:

Cycle 2 14% of 24 hrs 3.4 hrs @ 4.380 kw/hr = 14.9 kw

Could it be that the cylinder (buffer, thermal storage ) is badly plumbed, badly insulated?

If this "cycle 2" (quoted above) really repeats every day without domestic hot water being drawn then the energetic loss of the thermal storage would be 100% per day....

If it repeats every second day the loss would be 50 % per day,and so on...

About 20-30 loss would be normal with a small wet storage system, around 300-500 liters as long as no thermal energy is drawn from it,consumed by opening the warm water tap.

It can be done much better,with less losses. But this is not the standard we see installed.

RavenII

My cost meter only shows the daily & running total (I re-set it yearly on 30/10) . It can also show how many kWs the machine is drawing, but not the total kW in the period.... since you asked I just checked it and the good news is I have it set wrong...its on my old ESB rate of 17.6c Day and 8.37c Night - we're now on Airtricity at about 12% less, so my last year cost more like €1420 not the €1600 odd I measured!

At a third of the price of oil, its such a no-brainer; I think the title of this thread is stupid ....but you do have to run the things correctly and use a good heatpump.... Your bill won't be as high as you think, as I said before there's nothing else happening in the empty house...are the curtains even drawn in the evenings etc etc