Lets Talk Solar - opinions please!

freddyuk

Slieve wrote: »

Yeah. Got it installed at the start of February. Happy with it so far. Constant heat in the house, loads of hot water. if my calculations are right looks like halving my oil bills, with a constant heat in the house which we never had.

They want both parties for the presentation because it is a large investment, I personally am glad we were both there and made a decision on the information we heard from him and not second hand from one of us.

The important thing to remember is that you will need a second source, we turned the oil off in mid April and went solar from then. It was working great until last week when we had to turn the oil on again for two days, horrendous weather, turned it off again after that and it its all good again.

So when the heating is turned of (if you can turn it off) where is the excess heat
then stored? As you have a "reference" installation deal I guess you can show others how it works?
What size collector total area and what size thermal store do you have.

Slieve

Hey, I'm not getting into all that. I'm not here to sell this product. Get it in, don't get it in, I don't care. I got it in and so far I'm happy with it. If you want to find out more about the system then ring them.

air

Any idea how much electricity the system is using yet Slieve?
Would you be willing to share any photos of your installation?

Slieve

Electricity: It doesn't seem to have made any difference to electricity, I should state that I received an estimate reading and have not submitted an exact meter reading yet to get an exact bill.

Photo: The only difference that you can see are solar panels on your roof. There is a much larger water tank in the hot press, you don't see that until you open the door and they put everything else in the attic. If you were walking around the house you wouldn't know it was there.

air

Thanks Slieve.
So how does it provide heating to the house then?
Does the hot water tank act as a thermal store of sorts with heat taken out through a boiler coil to your radiators?
Is there a compressor or something in the hot press also?

freddyuk

There is nothing "clever" about the system. I have exactly the same solar set up with oil and stove feeding in energy. Having solar means the "free" solar energy is fed into a simple solar cylinder where it is stored until used. The solar input is in the lower coil whereas having this into top coil first and then transfer to the bottom coil is way more "clever" and efficient. You draw hot water from the top of the cylinder.
The boiler is then doing less work as the cylinder is preheated by solar all day long thus the water is only heated from maybe 35c averagely or not at all when the sun is shining. Savings on oil could be significant. This system is cheap and effective for domestic hot water and will potentially provide excess hot water in summer and a contribution in winter. Too much solar input and insufficient storage / cylinder means the system overheats in summer so systems have to be balanced.
If you want to have central heating running off this too you need a massively oversized solar collector hence the reason for 5 or 6 collectors on the roof. Also you need underfloor heating and/ or massively oversized radiators to work with low temperature water. If there is insufficient solar the boiler comes on as is normal to support the heating. Nothing "clever" there. It is possible to have control over normal radiator system and underfloor via a control valve but I don't know if the system is this clever or not.
Underfloor or low temperature heating is badly effected by draughty houses or poorly insulated houses thus this is the first priority to spend money on.
In winter the solar will not do much for the heating input so the boiler will be working providing low temperature heating via a TMV thus the boiler may not be suitable or working efficiently. This could be extra costs.
In summer the solar will be producing gallons of hot water and the heating is off so what happens to all that heat which is not used? Unless there is a "waste" dump via a by pass system then the system will overheat very quickly.
So by having an unbalanced system solar is a small contributor in winter and will be dumped to waste in summer ( if there is a device to do this).
So the difference between this system and mine is 3 or 4 times more tubes as the rest of the system seems bog standard technology.
Tubes cost hundreds not thousands.
I would be interested in knowing where my assumptions are incorrect or unreasonable?
Anyone with the system should have been given the figures to back up the claims.
The terms and conditions talk all about the money and nothing about the system performance or expectations.

John T Carroll

brightspark wrote: »

My wife would have no real understanding of the technology, just as I have no understanding of the many things she excels at. She would be bored listening to the presentation, her only concern would be how hot the water and house would be.

What I really needed to know was the cost of an installed system so that I could then decide if the cost of ownership, including servicing etc would be justifiable over the expected life of the system.

As others have suggested, it appears they rely on a particular sales technique to sell their systems instead of being able to make a proper economic case. I'm going with my gut instinct and won't be dealing with them again.

Had an acquaintance quizzing me re the feasibility of solar space heating for the past few weeks as he claims he can get 6 X 30 Tube (almost 20 M2) panels and a number of 300 Litre storage cylinders "on the cheap", he could ground mount them he says. He asked me to see what kind of savings he might expect with this set up before he makes any sort of move so I put a few numbers in this spreadsheet based on the Solar Radiation at Roches Point, Cork for 2014 Jan to April and Sept to Dec inclusive, I would think that this radiation amount wouldn't vary by much more than 10% on any year or at any location.

Wearb

Well done on those figures. I will check them on my computer later (on my phone.now)
Did you cost it to work out a payback period?

John T Carroll

Wearb wrote: »

Well done on those figures. I will check them on my computer later (on my phone.now)
Did you cost it to work out a payback period?

No, its not as straightforward as that as he already has a 40 tube array plus a 300 litre cylinder and what he wanted to see was the incremental savings with 20M2 during the winter months. Practically speaking he would have to use it it all year round to supply hot water as well but heat dumping would be an nightmare with that monster as he would need a 9 kw heat dump. He can self install everything himself, what is really driving this is the knockdown price, which he will know shortly, he has to take the lot. Of course he doesn't have to install the full 20M2, he may be able to combine the two systems, another (the proper one) calculation can be done then on a year round basis of supplying both his hot water requirements and contributing towards his space heating.

freddyuk

You have to factor in the storage and control cost. Do you shut down 75% of the system in summer or build a swimming pool.? Getting the basic kit cheap still requires the control and storage cost. What is the heating system it will feed?
There is a big danger of having plenty of not very hot water if the system is not carefully designed and controlled.
Series connection is ok for a limited number of collectors but then you have to go to parallel or have complicated control system which needs monitoring/maintaining.
Look forward to some calculations on the plan

Wearb

John T Carroll wrote: »

No, its not as straightforward as that as he already has a 40 tube array plus a 300 litre cylinder and what he wanted to see was the incremental savings with 20M2 during the winter months. Practically speaking he would have to use it it all year round to supply hot water as well but heat dumping would be an nightmare with that monster as he would need a 9 kw heat dump. He can self install everything himself, what is really driving this is the knockdown price, which he will know shortly, he has to take the lot. Of course he doesn't have to install the full 20M2, he may be able to combine the two systems, another (the proper one) calculation can be done then on a year round basis of supplying both his hot water requirements and contributing towards his space heating.

Looking at it on PC now. Nice piece of work. I see that if oil jumped to €1 the savings would be almost €500. That excludes the hot-water benefit in the summer also.
As for the excess heat, it would be ideally suited to a paddling pool or similar.
It is difficult to do a cost analysis on solar, with initial costs plus maintenance/replacements etc.

I have often thought of installing some solar (I don't have it here), but I have never been able to get favourable figures to justify it. ( I must get and input the solar output for the SE and see how much of a change it makes to those figures)

Thanks again for those figures. I know you are not trying to promote it, just giving the facts.

John T Carroll

Yes, of course it would need some very detailed engineering by someone qualified to do so, I was asked to look at it purely from any potential saving point of view.

John T Carroll

Wearb wrote: »

Looking at it on PC now. Nice piece of work. I see that if oil jumped to €1 the savings would be almost €500. That excludes the hot-water benefit in the summer also.
As for the excess heat, it would be ideally suited to a paddling pool or similar.
It is difficult to do a cost analysis on solar, with initial costs plus maintenance/replacements etc.

I have often thought of installing some solar (I don't have it here), but I have never been able to get favourable figures to justify it. ( I must get and input the solar output for the SE and see how much of a change it makes to those figures)

Thanks again for those figures. I know you are not trying to promote it, just giving the facts.

No, I have no vested interest one way or the other, I never gave solar space heating in Ireland a thought until I was asked to do this little exercise. I have now done the sums with the 20M2 supplying both space heating and domestic hot water, see spreadsheet. It is again is based on the solar radiation for Roches Point, Cork, but obviously for the full year, the 2014 solar radiation was 1084 Kwh/M2.

A few numbers from the spreadsheet based on oil fired heating cost of €0.68 per Litre.

Saving €378/annum using 100 LPD of hot water at 60C which equates to 147 LPD at 45C.

Saving €404/annum using 150 LPD of hot water at 60C which equates to 220 LPD at 45C.

Saving €429/annum using 200 LPD of hot water at 60C which equates to 294 LPD at 45C.

Saving €455/annum using 250 LPD of hot water at 60C whiche quates to 367 LPD at 45C.

The solar circ pump efficiency has a marked effect on the savings but I dont think I have underestimated this, however that may be pinned down more accurately later, if required.

My acquaintance now has three choices, Do nothing. Uninstall his 40 tube system and install the 20M2 as above or Retain his 40 tube system for hot water and install the 20 M2 system for space heating only and then mothball it for 4 months of the year!.

Option 1. He will continue to save around €160/annum based on his 40 tube system.

Option 2. He will save €429/annum based on a hot water consumption of 200 LPD at 60C.

Option 3. He will save €160/annum from his 40 tube system plus €345/annum from his 20 M2 system (space heating only) giving a total saving of €505.

He has a conventional oil fired system with radiators and cylinder coil, he uses around 16000 Kwh of oil. (1500 Ltrs/annum)

garybiz1

I got the system in last November and am very please with the whole set up. Major saving on heating oil. I was spending €2700 a year to heat the house and I estimate cost of oil is now €600 -€700. Always have hot water and house is always at a comfortable temperature. Yes it was expensive. €16000 with grants etc. that price is down to alittle over €12000 net price. took 2 days to install and cylinder was much bigger than the old one so did loose hot press space. Im only sorry I didnt get them to put the cylinder up in the attic. I can check the temperature of the panels on the roof and from my phone here in work. I can check temp in every room in the house also. Today is pretty overcast and temperature on the roof is 61 C... I must say I was sceptical of their claims, but Lets Talk Solar did what they said they were going to do.. "Transform our home" I would have no problem recommending them. I worked it out that between Electricity,Oil and solid fuel savings system will have paid for its self in 5 - 6 years. now thats taking into account the rise in fuel costs. This system also improved the BER rating I got the new results there last month. Was a D1 and now a C1. I have to say I did jump into this head first only to check out their claims after getting the system in but I found no customer complaints and all claims stated are facts.

Wearb

garybiz1 wrote: »

I got the system in last November and am very please with the whole set up. Major saving on heating oil. I was spending €2700 a year to heat the house and I estimate cost of oil is now €600 -€700. Always have hot water and house is always at a comfortable temperature. Yes it was expensive. €16000 with grants etc. that price is down to alittle over €12000 net price. took 2 days to install and cylinder was much bigger than the old one so did loose hot press space. Im only sorry I didnt get them to put the cylinder up in the attic. I can check the temperature of the panels on the roof and from my phone here in work. I can check temp in every room in the house also. Today is pretty overcast and temperature on the roof is 61 C... I must say I was sceptical of their claims, but Lets Talk Solar did what they said they were going to do.. "Transform our home" I would have no problem recommending them. I worked it out that between Electricity,Oil and solid fuel savings system will have paid for its self in 5 - 6 years. now thats taking into account the rise in fuel costs. This system also improved the BER rating I got the new results there last month. Was a D1 and now a C1. I have to say I did jump into this head first only to check out their claims after getting the system in but I found no customer complaints and all claims stated are facts.

Glad that you are so happy with your investment. Could you elaborate a little please. You say you were spending €2700 on oil and now about €700. Does this mean that it was costing you €2000 per year to heat your hot-water?

garybiz1

Wearb wrote: »

Glad that you are so happy with your investment. Could you elaborate a little please. You say you were spending €2700 on oil and now about €700. Does this mean that it was costing you €2000 per year to heat your hot-water?

No.. I think you picked me up wrong. I heat my house now with solar and gives me all the hot water I require. It uses the oil as a back up. I reckon I'm now saving €2000 a year on oil.

Wearb

garybiz1 wrote: »

No.. I think you picked me up wrong. I heat my house now with solar and gives me all the hot water I require. It uses the oil as a back up. I reckon I'm now saving €2000 a year on oil.

What sort of setup have you got that can save you so much? €2000 worth of heating oil would have given you about 55 Kw of energy daily. (That is if my head is working properly when getting a lie-in)
That is averaged out over the year and obviously that number would increase during the winter months.

I would love to be able to save that much.

mp31

Slieve wrote: »

Hey, I'm not getting into all that. I'm not here to sell this product. Get it in, don't get it in, I don't care. I got it in and so far I'm happy with it. If you want to find out more about the system then ring them.

Did you notice a difference in the hot water pressure e.g. does the shower appear to have more pressure?
Also, how many panels do you have?

Slieve

hot water pressure increased.

6 panels which I am glad of this summer with the weather!!!

esox28

we were working in a domestic house today that had 90 tubes 500ltr buffer and combi 170ltr dhw storage, the first floor of the house was 24*c due to the 670lts of 60*c stored water, tank and all associated pipework was lagged but even so its emitted secondary heat regardless.

im not convinced.

also i was reading about a 160*m passive house in mayo which has a total heat load of 10w/m* and a solar system of 40*m which by my crude calculations

would be 10'000kwh/annum from solar

and a requirement of 1'600kwh/annum

where does all the heat go in the summer? surely a 3kw electric, heater pv panels and maybe two panels for hotwater but not even necessary.

John T Carroll

esox28 wrote: »

we were working in a domestic house today that had 90 tubes 500ltr buffer and combi 170ltr dhw storage, the first floor of the house was 24*c due to the 670lts of 60*c stored water, tank and all associated pipework was lagged but even so its emitted secondary heat regardless.

im not convinced.

also i was reading about a 160*m passive house in mayo which has a total heat load of 10w/m* and a solar system of 40*m which by my crude calculations

would be 10'000kwh/annum from solar

and a requirement of 1'600kwh/annum

where does all the heat go in the summer? surely a 3kw electric, heater pv panels and maybe two panels for hotwater but not even necessary.

Assuming solar radiation of 1000 Kwh/M2/Annum
a 90 tube system with most manufacturer,s claimed system efficiency of 55% should give a yearly solar output of 5330 Kwh, in my opinion the efficiency would be closer to 45% giving 4360 Kwh/annum. On a good sunny summers day it should produce about 30 Kwh, enough to heat 573 Litres of water from 15C to 60C. (30*860)/(60-15).

John T Carroll

John T Carroll wrote: »

Assuming solar radiation of 1000 Kwh/M2/Annum
a 90 tube system with most manufacturer,s claimed system efficiency of 55% should give a yearly solar output of 5330 Kwh, in my opinion the efficiency would be closer to 45% giving 4360 Kwh/annum. On a good sunny summers day it should produce about 30 Kwh, enough to heat 573 Litres of water from 15C to 60C. (30*860)/(60-15).

40 M2 of Tubes would/should give respectively 22000 to 18000 Kwh/Annum and 2366 Ltrs/day of hot water....quite alot!.

esox28

John T Carroll wrote: »

40 M2 of Tubes would/should give respectively 22000 to 18000 Kwh/Annum and 2366 Ltrs/day of hot water....quite alot!.

no from what I could tell they were panels 500kwh/annum.

John T Carroll

esox28 wrote: »

no from what I could tell they were panels 500kwh/annum.

Fair enough, IF they are flat plates or similar, these would give an annual efficiency of around 25% and 500 Kwh/annum per "2 M2" F.Plate, I have 2 of these myself and get a measured fairly constant 1000 Kwh/annum. Are you actually saying that there are 40 M2 of installed Solar on this house?...if so then your number of 10,000 Kwh/annum, in my opinion, is spot on and a good summer day should give around 55 Kwh and 1050 Litres of hot water, so I agree, what do you do with it?? except you allow the system to stagnate or have a heat dump. In fairness, the Irish heating requirement goes on for 8 months of the year. A non passive house might need anything between 10,000 Kwh and 16,000 Kwh of energy per year for space heating alone and that system would make some bit of sense then.

freddyuk

I am still waiting for the answer to the "where does the heat go in the summer" question?
It may be the system on average can generate sufficient annually to heat a well insulated home throughout the year BUT in winter there can be 2 weeks solid of virtual darkness where the days are grey and very dull when the system is not replenished thus another source of heating is required. The system has to be able to heat the home AND regenerate the thermal store. A tall order with 4-5 hours of decent sun/daylight?

Slieve

Except this summer when you need the rads pumping out heat all day every day!!!!

freddyuk

Certainly true in West Cork!!

mp31

Slieve wrote: »

hot water pressure increased.

6 panels which I am glad of this summer with the weather!!!

Another question if I may - did the salesman use any hard sales tricks e.g. cost x but discount to y if you sign today?
I'm considering calling them but I don't want to have to go thru the sales spiel only to be told that the price is only discounted there and then. I like to get a quote and then think about it for a few days before making my mind up.

Slieve

No. Not on me anyway. He called and it was maybe a week later when we decided to get it in. There was no pressure put on us with regard to 'special offer if you sign now' sort of stuff.

mp31

Slieve wrote: »

No. Not on me anyway. He called and it was maybe a week later when we decided to get it in. There was no pressure put on us with regard to 'special offer if you sign now' sort of stuff.

OK thanks for that - it's a relief to know they are not doing that sort of stuff.

Sorry one more question (I should ask them all together but I can't think of them all at the same time ) - how is the system performing in this latest 'heatwave' that we are having. OK, I know it's a stretch to call it a heatwave but I'm guessing that your hot water tank is full of really hot water and so what happens to all the heat coming from the panels on the roof? Does it get diverted to a radiator somewhere in the house?