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Geo Theromal Heating
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does that include the presurrised cylinder (Is it a thermal store)???
yes that includes the pressurised cylinder - but it's not a buffer tank or anything - ie it's part of the hot water system and it doesnt share energy with the heating system - there's no real need for a thermal store as i am on nightrate electricity and i am not using solar/ wind or anyting - so it just heats up the slab and the hot water tank in the night time and i have the heat during the day - but it can also come on at daytime if it gets coldAre you sure it is an 18kw heat pump, I have got in roughly 10 quotes for a 2100sq ft house and the max pump they recommend is 12kw.
pretty sure yea !!! - it was a size too big for the house but the company says its better to go a little too big so you have room to expand, etc. however the plumber who put the system in ( who is not really connected to the heating company ) said that he just worked on a house where the heat pump recomended was too small - so it can happen - i would at least give ecoheat a shot at a quote - they have a completely different approach to all the others - imo the more aspect/perspective you can get on a job like this the better !!!What sort of electric bill are you running?
dont know yet -- but be warned power bills for underfloor heating are massive for the first three months while the slab heats up and dries outHow long does it run for at nite?
not sure yet - too much other stuff on my mindDoes it mean you have constant heat in the UFH and hot water on demand?
well having ufh more or less implies constant heat anyway afaik - even if it's on a trad boiler - that's the way the systems are designed to operate - so the heat pump doesnt change this afaik
-- yes 24 7 hot water !!!
I presume it is a brine system you have in?
i dont think so !!! why would it be - you mean in the ufh - ?? - no the pipes are filled with regular waterAnybody know if it's possible to mix geothermal and wood pellet systems (as a kind of back up/supplement to the geo) or am I going for overkill?
first off i'd say imo it's a tiny bit overkill - but then it's your house so do it your way - on my system i know there is a facility for a backup boiler but a regular oil boiler would probably do as you will hardly ever need to use it - i mean it's not like the geothermal will not get enough heat or anything - however it's worth remembering that geothermal runs on esb so if the power goes for a few days you could be screwed unless you have a generator ( i invested in one myself - buy and sell 400 for a 5.5kva and then i got the electrician to install a transfer switch ) - which i suppose could be a little overkill in itself .... in general though i would be thinking more in terms of a backup system than a suppmental system - unless you go for solar/wind in which case i think you need a buffer tank to work it properly - and when i investigated that it was pretty costly
also the hot water cylinder which i got has a few spare coils which mean that i could potentially suplement the domestic hot water heating using solar/wind/backboiler or whatever ---that could save on the esbI think you can go for a dual coil buffer tank with some systems, one coil supplying heat from the geothermal and the other coil supplying heat from the open fire with back boiler, stove with boiler, oil boiler, gas boiler, etc.
yes it would make sense that if you had a buffer tank for the ufh you would be able to have a couple of coils in it which means that you can store heat from whatever heat source is available at the time - ie solar/wind/back boiler - so solar when it's sunny, wind when it's windy, back boiler when you've got the fire lit -- but it makes no sense to me to have an oil boiler connected to a buffer tank as it's always the same - ie you can turn it on at anytime an so there's no need to store the heat for later when you need it - the only real place an oil boiler has with a heat pump is in a backup scenario as the two do basically the same thing and if you are running a backup system then there's no need for a buffer tank as that's more for supplemental - you could however have a heat pump running an oil boiler as a backup and then having a buffer tank for use with solar/wind/bboiler but that could get really expensive
myself i have the generator as backup in case the power goes down and i MIGHT get a buffer tank in the future for use with a wind gen but afaik those things take about 14 years to pay for themselves
ps all this reminds me that dedicated cylinders are huge - and buffer tanks are even bigger and you really need to incorporate a suitable space for them aswell as all the rest of the plant - hot press just wont do- except it's a cool place for the ufh manifold --- also if you stick it on the end of a bungalow as i did then you'll have to wait a full minute for the water to come hot in the tap !! dont say you werent warned !!!0 -
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Thanks for the update, I can understand the oversizing alright, it gives you more room for expansion.
On the brine - this is the mix , water and anti-freeze that is pumped outside in your loop for the geo. I presume you have about 6 or 700 metres of pipe in the garden??
There now seems to be this D/X (Direct Expansion) system out there that uses a refrigerant instead of the brine, it means about 1/6th the amount of pipe and they say it gives you heat to 80 degrees Cent. so no need for domestic water kits or heat plates, as well as that they do not require a pump as the brine system does so therefore cuts down the number of working parts and also the cost of running the system.
The argument some companies have is that if you have your large thermal store or buffer tank is that there is store of water built up over night and you use it away, I presume you have the same idea, did you say you paid 4k for the cylinder???
Then there is the air 2 air solution!! Choices smoices, I will be gone mad!!
I was talking to a girl here at work and they have a 3300 sq foot castle, I mean house, and they have geo.
There elect bill was 500 yoyos for the 2 months. Have UFH as well.
Where are you based do you mind me asking???
I presume it is Lenister??
Did you get many other quotes??0 -
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Great topic - finally some people who have heard about Geothermal!! Read ALL the posts and must say - thanks for being so honest, the choice is amazing not to mention the price variations!!!
So, tons of ???s
Just building a 2700 sq ft block house on 2 acre site and would like UFH on both floors with geo thermal (thinking of Dunstar??), so here goes with the ???s
Don't want to pay ESB all that money on the pump - what other options do I have?? Have a south facing roof so was think solar but don't know anything about it or it's effectiveness and how it would work (doing my own electrics so not sure about this). Also thought about wind as site is quite windy BUT still concerned about the potential health hazards (I know, I know - not proven blah, blah, blah but don't want to take the chance).
Have 4 showers - do I need to go the "Bob" route in terms of hot water - hoping not?? If I don't go down Bob's route - what options do I have for hot water outside of immersion??
Can I integrate a solid fuel option with UFH and hot water even when using geo thermal??
Yop - you seem to have done some serious research - what did you decide in the end - let me know if you would prefer I PM you for that info??
Really appreciated any help - Deadwork is started so need to make decisions NOW.
BTW - why are there no other girls on here??? - do we only build our own homes in Cork??
Thanks in advance
Pitstop
PS - Saw a new development of 8 houses last week-end - developer used geo-thermal as a major differentiator to the market - the more popular it gets, the better!0 -
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BTW - why are there no other girls on here??? - do we only build our own homes in Cork??
Nope, I'm building my house in Wicklow...
Good questions though, I'm thinking along the same lines as you. I'm not happy about that ESB bill as I was hoping to be as self sufficient as possible. Anyone know the electricity needed to power a pump like that (like KWh per year etc), and whether wind/solar/both will do the job most of the time with ESB power there as back up.
If I were to integrate solid fuel (I'm thinking wood as it's CO2 neutral) would a rayburn do the job?0 -
Anyone know the electricity needed to power a pump like that (like KWh per year etc), and whether wind/solar/both will do the job most of the time with ESB power there as back up.
i think in our case the system takes 3.3kva -- which would mean that for instance if you had a petrol generator or something like that ( i know you wouldnt but just for ilustrative purposes) then you would need a 3.3kva generator for the heating alone
please double check that figure it is only from memory and i was never 100% sure of it anyway
oh and i think the esb provide you with a 12kva supply for a domestic house
the trouble with alternative sources of power like wind and solar is that they are not there all the time -- which means that you need to store them - which from an ufh point of view means that you either need in the case of wind power to get a battery bank and an inverter ( very expensive ) or in either case you can use what i think is called a buffer tank - also very expensive and very large ( though i think your domestic hot water cylinder can be incorporated into it also which saves a bit of space )
next problem is that with the battery/inverter setup the batteries will only last so long before you have to replace them - and they are the most expensive bit --- it all comes down to payback time and afaik the payback time on these systems is just too long ( it could be 10 - 15 years ) with very little other benefits
-- this seems to be one of the major benefits of the windsave system in that you dont have to worry about storage as the electricity is used straight away - having read about these in the last day or two i am not considering the notion that as heat pump houses would have a normally high esb bill that they could benefit from more than one of these devices - any comments anyone ???wind/solar/both will do the job most of the time with ESB power there as back up
this is the idea i originaly toyed with but i gave up on it because of the high cost of storage -- you should have a look into the windsave yourself as it seems a better idea than a standard turbine
solar - an ideal use of solar is to heat your hot water --- i think you can get 60% of your hot water free from the sun or something like that - i plan on investing at some stage myselfHave 4 showers - do I need to go the "Bob" route in terms of hot water - hoping not?? If I don't go down Bob's route - what options do I have for hot water outside of immersion??
im offended
-- no just kidding !!!
afaik the only real options are:
1 - use main hp to heat dom hw - ( prob is main hp comes on during summer and water may not be that hot so supplement with immersion and/or use a large ( HUGE) cylinder - or else put up with only one bath/shower at a time as cylinder will have to fill and heat again - ok for small occupancy )
2 have a secondary heat pump - this is what i did - pretty expensive but obviously i thought it was worth it - 24 7 365 cheapish hot water / pressurised system - no need for shower pumps - main heat pump doesn't come on if not needed
3 supplement either 1 or 2 using solar/wind/back boiler --- starting to get a bit expensive again i think but you might manage free hot water - in fact this is what i'm aiming at
4 same as 3 but have the primary emphasis on the solar/wind etc power
5 immersion only - argghh
6 cooker or something like a range heating the hot water
there are many other ways of heating your water but these seem like the most likely ones to me - it basicaly comes down to having either one or 2 heat pumps and either supplimenting that or not with wind/solar etc or else relying primarily on wind/solar and use an immersion for backup
i think this covers it but i'm open to suggestions and correctionsCan I integrate a solid fuel option with UFH and hot water even when using geo thermal??
not sure about the ufh ( you might need to have some kind of a buffer or something where the hp heat and solid fuel heat can mix ) -- but you can certainly do it with reguard to the hot water anyway i think because all you need is to have an extra coil on your cylinder and put the solid fuel heat through one and whatever you're using to heat the water through the other ( get lots of spare coils is my advice - you never know when you''ll want them)UFH on both floors
pitstop i did ufh upstairs on my house and i did the concrete screed method upstairs ( you can use the battens method either ) -- well just to say that it was a great decision - i dont think it was a large expense and the floor upstaris is very solid with minimal floor/ceiling noise too - everyone comments on it
another thing i think you should do is to put insulation between the floors - this is not normally done but it gives you a better chance of containing downstairs heat downstairs because all that heat downstairs can make upstairs pretty hot and you might not like it that wayI presume when the mains is not on the windsave doesn't provide your power.
i would say you are correct -- the windsave system needs to put it's ac output in phase with the house's , so it presumably copies it - and if the house has none then i would think it might not have anything to copy so it wouldnt surprise me if it just stopped - also it would not be safe to provide the power to the house though the ring main - i mean if someone turned on the hob ,oven and drier or something toghter then the ring main would be under serious pressure to cope --
personally i have a small backup generator powering the house via a transfer switch in case of powercut but i would imaging that the windsave would reference against that and it would take some of the load off the generator and give me a bit more headroom in terms of what i could turn on if the esb power was off-0 -
Bob
You're a star - thanks for all the answers!
Re: UFH - Do you have a first floor slab or joists - sounds like a slab - going with joists, but going with some sort of screed on/between them otherwise it's not going to be as effective.
Sounds like I will go your route (I really want that extra water!! - very clean people here ) and then put in windsave as well. I might also look at the solar option - I have loads of south facing space for it but as you say, the costs are not in the panel itself. However, as it will all add up in terms of costs, it's probably easier for me to add the winsave later than solar so that might make my mind up.
Had a politician at my door last night (Paddy's day - what's that about??) - told him my views about no grant aid for this - agree with you that it's bloody ridculous!!
Thanks a bunch - sorry, but I'm gonna plagued you with ???s!!
Pitstop0 -
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bobmurphy wrote:pitstop
joists - 9 by 4 i think ( or 3 maybe ?? ) - i can find out if you want. QUOTE]
Thanks Bob, one job that I now clearly know what to do!
Were the joists 4 or 3 because of UFH, standard is 9 x 2 (according to me )!!
Thanks again
Pitstop0 -
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got a 300L Buffer Tank/Thermal Store/Cylinder, he has his rads running off this, unlimited domestic hot water.
300l = 60gal -- that's only a standard size tank - considering that heat pump domestic hot water is not at all as hot as oil burner hot water, it seems like a small cylinder for his hot water needs let alone using it as a thermal store - personally i would want to have at least that for the domestic hot water - unless he has some way of getting the water a lot hotter !!!
i talked to a guy about a thermal store a while ago and it cost about 7k alone - i always thought that you needed to have a really big cylinder to use it as a thermal store !!! i really would not want my ufh to be able to "steal" my hot water on me just because the house got cold at the same time as i wanted to have a shower - think about it - you would def need contingency as it could get a bit messy !!!
just my 2c worthWere the joists 4 or 3 because of UFH, standard is 9 x 2 (according to me )!!
no the builder put them in that size because he's into that kind of thing i think - i didnt know any better at the time - but it's no harm anyway because they have to support the slab aswell as everything else - i'm really happy with them that way now !!0 -
yop wrote:PitStop - That 8k was for the whole unit, Air Source heapump, tank and controller unit.
I think that it is actually a good price.
Yip D/X is the way for me alright, I downloaded a couple of University papers from net last nite so I will be reading them to see if Air Source or Ground Source is the best system.
Ahem.....that is a good price - all in - WOW!
Yop - thought you were not into Air Source earlier on - did something change your mind???bobmurphy wrote:no the builder put them in that size because he's into that kind of thing i think - i didnt know any better at the time - but it's no harm anyway because they have to support the slab aswell as everything else - i'm really happy with them that way now !!
Happy with that - no harm in this at all (although me pennies are well spent so won't do ANYTHING extra at this stage)
Night lads
Pitstop0 -
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