Free solar system?

unkel

Flyer in the letterbox this week from Ecolodge stating:

Package II

This higher capacity package is designed to meet hot water demand of larger families with 4+ members. It is a fully equipped solar system with all key components present including a 250 L hot water storage tank. This is an amount of water sufficient for almost any rate of daily consumption.

Specification for the package is as follows:

2 × 18 tube vacuum collector (6.0 m2 total area)
250 L stainless steel water tank with a double coil immersion heater
Expansion vessel 24 litre
Single line pump station and control unit

Cost of package II : .......................................................€2150
Estimated installation cost: ........................................... €1300*
SEI grant: ................................................................... € 1325
Cost to you: ............................................................... € 2125

*(all installation material such as fittings, pipes, valves etc. are included in this estimate)

Estimated payback time 36-48 months

With the option of "pay as you sav€" : "is a finance offer where your monthly installments equals the savings made by your solar system. Terms and conditions apply"

They also state in the flyer that Dublin receives more sunshine than Paris

Seriously tempting. Can't seem to find the terms and conditions on their website http://www.ecolodge.ie though...

Any advice? The rear of my small semi-d house is south facing and the roof has 2 large and 1 small Velux window (attic conversion).

gizmo555

It is generally accepted that a good rule of thumb for Irish conditions is that a well specified and installed solar h/w system may provide up to 60% of a household's needs.

This proportion can be reduced significantly by factors such as dishwashers and washing machines, which typically account for about 20% of hot water usage. Almost every such machine on the market now has a cold water only inlet and heats water internally, meaning this hot water use can't be replaced with a solar h/w system. Things like electric showers can reduce the amount of hot water usage available for substitution with a solar system even further.

So, for most households a good solar system can produce 60% of 80% (if you follow my arithmetic!) of your hot water needs, i.e., just under half.

Now look again at these figures and ask yourself is it really plausible that you currently spend between about €1,000 and €1,400 a year, just on hot water?

gizmo555

Just had a look at the Ecolodge website and they give an estimate for a 4.9m2 system that it will yield 1,302kWh in energy annually This on its own seems reasonable enough. Increase this by about 20% for a 6m2 system to, say, 1,600 kWh.

The most expensive energy this could be substituting for is day rate electricity at 16c/kWh. So the system would save about €260 p.a. If the energy being replaced was from, say, an oil fired-boiler or night rate electricity the savings would be much lower.

These figures are, to put it mildly, inconsistent with the estimate above that one might save over €700 p.a. from such a system

unkel

Thanks a mill, I was hoping for some replies with numbers.

Some of my thoughts on this. The 36/48 month payback time they state is clearly rubbish. That said, if I could save 260 p.a. as per your post, the payback time (ignoring interest) is about 8 years. Not bad at all compared with most rough ideas of payback time on any solar project I've seen. And pay back is one thing, after pay back you start making money and making your home more valuable / easier to sell. And of course help saving the world

More details about my situation. We're a family of 5 (3 kids under 5) so lots of showers / baths and lots of runs of the washing machine. Our washing machine does indeed take a hot water feed and we run about 7 or 8 full washes a week. Our dishwasher does not take a hot water feed, so no savings there.

We heat our water via the gas boiler in winter, but we use immersion in summer, typically from mid April till the end of September. I presume we would have very little savings during winter, but most during summer. We do indeed pay the day rate of 16c per kWh for our electricity (the cheapest available to us: Bord Gais, direct debit - the dual meter would not really give us any savings last time I checked)

And there's the luxury aspect. The water pressure in our showers was just about adequate (as in any cheap recently built Irish house, I suspect) until we converted the attic, meaning the attic water basin was moved down to the corner of the attic, losing at least a metre in height. We've had bathroom upgrades, including an electric waterpump in the hot press. This works great, but empties our standard water tank (are these 120l?) in about 10 mins at full flow. That's not great. A 250l tank would be lovely to have especially knowing that heating it wouldn't cost anything.

unkel

Quick analysis of my electricity consumption:

1095 late dec - late feb
897 late oct - late dec
1391 late aug - late oct
1486 late jun - late aug
908 late apr - late jun
1043 late feb - late apr

Total 6820 kWh

Rough guess is that 900 kWh per two months is needed for non-water heating in winter and 500 in summer. Say something like:

900 late dec - late feb
900 late oct - late dec
700 late aug - late oct
500 late jun - late aug
500 late apr - late jun
900 late feb - late apr

Total 4400 kWh

So using 2420 kWh p.a. on heating water electrically. At 70%

gizmo555 wrote:

most households a good solar system can produce 60% of 80% (if you follow my arithmetic!) of your hot water needs

efficiency during the summer and 0% efficiency during winter (I'd like to take the prudent approach) we are talking a saving of 70% of 2420 = 1694 kWh (pretty close to the figure of 1600 kWh you quoted, gizmo555) so at 16c we are talking a saving of €271 p.a.

saibhne

unkel wrote: »

T


And there's the luxury aspect. The water pressure in our showers was just about adequate (as in any cheap recently built Irish house, I suspect) until we converted the attic, meaning the attic water basin was moved down to the corner of the attic, losing at least a metre in height. We've had bathroom upgrades, including an electric waterpump in the hot press. This works great, but empties our standard water tank (are these 120l?) in about 10 mins at full flow. That's not great. A 250l tank would be lovely to have especially knowing that heating it wouldn't cost anything.

Hi Unkel, Their prices are pretty reasonable though there a few things I would check:
1. Your attic conversion could cause a significant obstacle to the pipe run - (it is the first question we ask when talking about the roof space) so your installation may not be straightforward and thus your installation charge will likely change because of this. Before committing get a solid quote for the installation
2. It sounds like your pump pumps at about 12L per min which for a 5 min shower is 60L per shower, for five of you to have a 5 min shower in the morning and to feed your washing machine you will need a bigger cylinder then 250L. 300L would be minimum here in my opinion and maybe consider installing a less powerful pump as well - water charges are on the way.
3. Are these prices inclusive of VAT? There is a little anomaly here in that the materials price if bought alone is subject to 21% VAT and the labour charge 13.5% - if purchased together the labour component needs to be more than 33% of the final cost to be eligible for the 13.5% rate. I have to say the installation charge of 1300 incl VAT and all pipework, insualtion and fittings seems good at first look.
4. The surface area of the heat exchange coil within their cylinders is quite small. With solar you should look for 20% of the surface area of the array to be represented on the surface area of the coil in the tank. This is to maximise your heat exchange from the panel to the water in the cylinder. It's a little more difficult to gauge the surface area with evacuated tubes but the rule of thumb for a 300L cylinder would be a solar coil with about 1.2m2 of surface area - theirs is 0.7m2 http://www.ecolodge.ie/Domestic_solar/domestic-solar-components.html

Cheers,

S.

unkel

Some great points there, saibhne. Thanks for your help!

1. Attic conversion making installation more difficult - I would make sure I'd get a fixed quote

2. Capacity. I should have been more specific. We're talking 2 adults and 3 young kids (under 5) here. Not 5 * 5 minute showers first thing in the morning More like 1 * 5 minute shower first thing in the morning, 1 * 5-10 minute shower a few hours later plus a baby bath (equivalent to a 1 minute shower) plus a full bath every other day in the evening. As it stands the 120l is adequate. Double that would be more than luxurious!

3. As for the VAT, it is not directly stated it is included. That said, on the flyer it says "cost to you" and on the website it says "price to pay". This implicitly means the VAT is indeed included. When quoting a consumer (not business) price I think it is a legal requirement to quote the price including VAT anyway and a flyer was dropped in peoples homes and the website prices that match the flyer were in the section "domestic solar systems - price list"

4. I'll keep that in mind and I'll look into that further! I'm obviously a complete novice in this area and if it wasn't for comments like yours, I'd have been ignorantly accepting anything offered to me. Thanks again!

saibhne

unkel wrote: »

Some great points there, saibhne. Thanks for your help!

2. Capacity. I should have been more specific. We're talking 2 adults and 3 young kids (under 5) here. Not 5 * 5 minute showers first thing in the morning More like 1 * 5 minute shower first thing in the morning, 1 * 5-10 minute shower a few hours later plus a baby bath (equivalent to a 1 minute shower) plus a full bath every other day in the evening. As it stands the 120l is adequate. Double that would be more than luxurious!

No worries Unkel! Just a quick word on the capacity, an evacuated solar panel should last at least 15 -20 years or so, through this time your kids may grow up to be shower hungry teenagers.. (although by then they may have different views on water conservation.) The point is that to get the best economy out of a solar system it needs to operate in the long term so you should consider future proofing your system if you can. You would be the best judge of that!

Cheers,
S.

selfbuildache

I'm also looking onto Solars at the moment and the name Ecolodge rang a bell - back last summer they were a timber frame company (I had emailed them for a quote for a house we're building.)
I'm about to email them now for a quote for solar (thanks OP!) but am wondering if there's anything to be suspicious about in that they seem to have completely changed operations - or am I missing something obvious??

I've just spoken to an Ecolodge rep. who told me he'll 'have to get back to me' as to why there's no website for the timber frame company anymore....??

quentingargan

One more point I would add to this; Their system doesn't seem to include a heat dump. When the cylinder is up to temperature, the system has to shut down. The water in the panels boils, turns to steam (which is sent to the expansion vessel), and evacuated tube systems will reach 220 degrees. This damages the anti-freeze, damages insulation in close proximity to the panels, and puts undue pressure on seals in the system.

There are other technical specs, and claims on the website that would worry me, but I have to say that I wonder about a company that is peddling the notion of a 3 year payback time on a system. They know better than that :rolleyes:

Crazy Taxi

Even in winter these vacuum tube systems generate enough heat to pre-warm your cylinder and therefore give your boiler less to do! <SNIP>

Edit: Do not name company on thread.
The following is taken from the forum charter: Any threads naming specific companies/traders will be deleted. Read the charter before posting again.

ccsolar

Hi
Just a few things about this flyer and quote.

1. The 250ltr water tank with this system is a bit on the small side. You would be better to go with a 40 tube and 300ltr tank in a family home.
2. You will most definitely need a heat dump with this size tank as these tubes are very high peforming.
3. The tank itself is a good quality tank but I think it only has 1/2" coils where as most tanks now come with 3/4" coils. The warranty with most stainless steel tanks is 20/25 years. How long is the warrenty on this tank? Possibly only 5 years.
4. The heating element is only a 2kw and the diameter is different than most sizes available in Ireland and you might have to look around in a few years for a new element.
5. The SR 962 controller in the flyer is not the controller that you have been quoted for as this controller is a Dual pipe controller and you have only been quoted for a single pipe/line controller. Is this not false advertising?
6. I think that you have been quoted for the SR961 controller which is the basic model.
7. Their website states that this controller has a manual heating function. This is correct if you only have a 2kw immersion in the tank otherwise you will also need a relay installed as the controller only has a max output of 10amp.
8. It also states that it can be used for system venting. This only applies to the dual pipe controller(SR962). Not the single pipe controller.
9. The SF flat plate solar panel collector on their website is NOT on the SEI register list at present but this site might not have been updated yet. The SF collector Might Not Have the solar key mark Cert according to my research.
10. The tube collector that is on the flyer has a solar key mark and is SEI registered.
11. The quote is very good but the fitting cost is over inflated in my opinion. If you buy the system supply only, will you still get everything you need, for example materials such as fittings, pipes, valves etc. OR will your installer have to buy some of the fittings himself.

CC

ccsolar

selfbuildache wrote: »

back last summer they were a timber frame company (I had emailed them for a quote for a house we're building.)
I'm about to email them now for a quote for solar (thanks OP!) but am wondering if there's anything to be suspicious about in that they seem to have completely changed operations - or am I missing something obvious??

I've just spoken to an Ecolodge rep. who told me he'll 'have to get back to me' as to why there's no website for the timber frame company anymore....??

Selfbuildache.
I was also trying to contact them a few months ago but the ph was no longer in service and the window/timber frame web site has been taken down and replaced with solar.
I think you are missing the obvious.
Was the reps name Aiden?

CC

theg81der

First a few points -

Is your roof south facing? (if not forget about it)
Is it approx 30 degree angle?
Is the product of good quality? (you can`t tell from a picture, it could be rubbish)
Are they reputable plumbers?
Are they insured?
Will you use €3450 on heating your water? (I very much doubt it)
Can you predict the Irish weather, last time I looked it wasn`t the mediteranian?

quentingargan

theg81der wrote: »

Is your roof south facing? (if not forget about it)
Is it approx 30 degree angle?
Is the product of good quality? (you can`t tell from a picture, it could be rubbish)
Are they reputable plumbers?
Are they insured?
Will you use €3450 on heating your water? (I very much doubt it)
Can you predict the Irish weather, last time I looked it wasn`t the mediteranian?

It is perfecly feasible to put panels facing away from south as far as east / west, or even east and west. You may need a slightly larger panel area, but this does not push up the overall project price significantly, particularly with vacuum systems.
30 degrees is optimum for midsummer production, but usually you are trying to optimise production for spring and autumn. There will be plenty of hot water at mid-summer. I would argue that a pitch of 40 to 45 degrees is better, but it makes little overall difference.
The payback time on a system depends very much on your hot water use obviously, but oil is the only commodity I know of that went up by 700% in such a short time. OK, that fell back to about 350% currently, but I think forecasting the amount of money you will spend on hot water in the coming years is even more difficult than forecasting our weather.
And lastly, solar panels, particularly vacuum systems, work well in this climate and don't need to be on the Med.:rolleyes:

theg81der

I don`t agree, theres too many variables involved and the price is overinflated.

The point about the Med is it offers a gaurentee of conditions whereas here theres no guarentee :rolleyes:.

I`m a fan of renewable energy and I wouldn`t touch this with a barge poll.

unkel

theg81der wrote: »

I`m a fan of renewable energy and I wouldn`t touch this with a barge poll.

I'm a novice in this field, but a €2k system that will save €250 per year (a very conservative figure, not taking into account any winter savings) is about the quickest repaying renewable energy system I have seen in this country, isn't it?

And yes, my roof is 100% south facing and I don't know the angle but I would guess it is in the 30-40 degrees range.

theg81der wrote: »

the price is overinflated.

Have you seen any other 250l system for less than €2k?

ccsolar

Hi Unkel

1. The price of the fitting is overinflated.
Could this be to hide the cost of some of the fittings?

2. These panels should work between 10 degrees and 60 degrees.

3. The price of the system you have been quoted for does not look like the same as the system on the flyer. The controllers are different.;)

4. Is the VAT inc?

CC

unkel

ccsolar wrote: »

1. The price of the fitting is overinflated.
Could this be to hide the cost of some of the fittings?

All fittings are included in the fitting price - or so they say. The bottom line would be the total fixed price, I'd make sure of that.

ccsolar wrote: »

2. These panels should work between 10 degrees and 60 degrees.

Could you explain in simple terms to a n00b what this means?
What happens when the water in the tubes goes over 60 degrees?

ccsolar wrote: »

3. The price of the system you have been quoted for does not look like the same as the system on the flyer. The controllers are different.;)

Yeah I got your point. I'd look into this before I'd go ahead.

ccsolar wrote: »

4. Is the VAT inc?

Yes it is included, see my previous points on this

ccsolar

unkel wrote: »

All fittings are included in the fitting price - or so they say. The bottom line would be the total fixed price, I'd make sure of that.
Could you explain in simple terms to a n00b what this means?
What happens when the water in the tubes goes over 60 degrees?

Yes it is included, see my previous points on this

Sorry Unkel
The 10-60 degrees is the roof angel not water temp.
There is no water in these tubes only in the manifold at the top of the collector.
€1300 for 2 days work is a lot, and what about the warrenty on the tank?

CC

pirateireland

We have flat panel collectors which is a copper pipe with a heat absorber panel/fin, all painted black inside a glass case. While not the evacuated tubes (which are more efficient) the collector is still a good way to go. I can't give you exact numbers right now but we have a temperature read out in the hotpress that tells us what temperature the water in the tank is and what temperature it is on the roof i.e. in the collector pipe work, which inturn goes through a heat exchanger and heats the tank.

Even on overcast not so warm days of 8-12 degrees. The collector still heats the water. Obviously best results is when the sun is splitting the proverbials, but as previous poster said collectors can warm the water to reduce heating requirements.

On hot sunny days sometimes the water is BOILING on the roof, and 50, 60 odd degrees in the tank. The whole tank mind.

20 mins of your immersion will not heat the whole tank, just enough for a shower maybe. The Immersion...god help us!

My advice would be to invest in a bigger tank too, because you will find the tubes will heat your regular tank in no time.

These systems do work if installed correctly by certified tradespeople of course. They will save you money, it is an investment over time but well worth it. Don't mind the people who nay say them. We're lucky to have a turbine, PV panels and water heaters, sometimes our ESB bill is €0

quentingargan

unkel wrote: »

What happens when the water in the tubes goes over 60 degrees?

If you are in a soft water area, you can let your cylinder go up to 85 degrees, and bring it down to 60 degrees using a thermostatic mixing valve. The mixing valve should be standard practice on all systems, but it often isn't. If the cylinder is at 85, the panel often will be at 90 to 100 degrees. That's fine - the fluid in the system is under pressure and won't boil until it gets to somewhere between 120 and 140 degrees, depending on the pressure.

If your water is hard, because of limescale, you can't let the cylinder go above 60 degrees. That is where this figure comes from.

But what happens, when you go on holidays and don't use yesterday's water? Or if it is an exceptionally good day and the cylinder is up to temperature at 2.00pm? On the vast, vast majority of systems installed, the controller will stop the pump. The fluid in the panels will heat up to 140 degrees, boil, turn to steam, and the fluid will be pushed into the expansion vessel. The panel will then continue to rise to about 220 degrees centigrade. It can't be helped if this happens during a power cut, and it is safe, but doing it regularly puts stress on the fittings, over-heats the pipe insulation in close proximity to the panel, and it rapidly degrades the anti-freeze fluid.

To prevent this, you can install a heat dump. This usually consists of a diverter valve which directs the fluid from the panel through a radiator to dump the surplus heat. Often this is put in the bathroom (but must be positioned high to prevent someone covering it in towels). In other houses, it is put into the loft. The radiator(s) must be large enough to disperse any heat the panel can generate.

The heat dump is best practice, but seldom included in bargain package prices. Most controllers include a relay for it, a high temperature motorised valve is about €150 and the radiators, pipework etc. probably another €100 or so.

There have been problems with systems that didn't have heat dumps. Usually they manifest their problems while the family is away on holidays. It is a false economy that will severly shorten the working life of systems and ultimately cost more in most cases, particularly where a system is designed to maximise the amount of the year over which it will work.

You cannot design a system that provides 100% of your hot water in March, April, August & September, but doesn't have a surplus in May, June & July. You can mitigate the problem by under-sizing the panels and topping up the hot water supply during spring and autumn, but that is a compromise, and it still doesn't get you through the holiday periods.

Bugnug

gizmo555 wrote: »

It is generally accepted that a good rule of thumb for Irish conditions is that a well specified and installed solar h/w system may provide up to 60% of a household's needs.

This proportion can be reduced significantly by factors such as dishwashers and washing machines, which typically account for about 20% of hot water usage. Almost every such machine on the market now has a cold water only inlet and heats water internally, meaning this hot water use can't be replaced with a solar h/w system. Things like electric showers can reduce the amount of hot water usage available for substitution with a solar system even further.

So, for most households a good solar system can produce 60% of 80% (if you follow my arithmetic!) of your hot water needs, i.e., just under half.

Now look again at these figures and ask yourself is it really plausible that you currently spend between about €1,000 and €1,400 a year, just on hot water?

Gizmo,

Are you sure about those figures? €1000 to €1400 a year on hot water? The price of space heating for the average Irish house is around €1400 to €1600 per annum and water heating equates for approximately 25% of that again. Solar installations cost around €4k to €5k if you take into account disrution and replacement of the cylinder. You would heat a tremendous amount of hot water for that kind of money. I would be more inclined to spend my money on insulation.

recedite

The SEIA grants for a solar system are based on the panel aperture area.
I notice that the strategy here is to use a lot of tubes, tightly packed,, and skimp on everything else. This maximises the grant and inflates the heat output figures a bit beyond that which might get used. The aperture ratio of 0.75 is good for evacuated tube panels. Not a bad marketing ploy I have to say, in these times when the punter won't pay out for anything.:)

quentingargan

recedite wrote: »

The SEIA grants for a solar system are based on the panel aperture area.
I notice that the strategy here is to use a lot of tubes, tightly packed,, and skimp on everything else. This maximises the grant and inflates the heat output figures a bit beyond that which might get used. The aperture ratio of 0.75 is good for evacuated tube panels. Not a bad marketing ploy I have to say, in these times when the punter won't pay out for anything.:)

Actually, on the system shown, it is the gross area that is 6 sq m. The aperture area of a system with 36 tubes would be about 3.4 sq m (giving a grant of about €1020. However, the grant appears to be €1325, which I assume is courtesy of reflectors (which SEI, mistakenly in my opinion, includes in the aperture area).

Reflectors really confuse the issue because they substantially improve the performance of panels during their EN12975 tests. They rely on reflectors shining light up into the back of the tube. However, after a couple of years in Irish weather, either the reflectors themselves, or the back of the tubes are usually filthy and there is no effective gain from the reflectors.

However, you now have the wind loading of a huge flatplate panel, surface mounted on your roof. I prefer to have systems without reflectors - the wind blows through the tubes and you don't get anything like the lift and buffeting you will have with a panel that has reflectors included. Most importantly, the output is consistent with the figures that are used in computer simulations which are designed to match cylinder, panel and household use.

recedite

OK so the reflectors are perhaps better at harvesting grants than actual solar energy.:D

The other thing here is the FREE idea based on Pay As You Save.
The Pay As You Save scheme is not up and running yet afaik .
In Pay As You Save, you don't pay the capital costs, the utility company does. Then they keep the fuel bills at the previous level until all repayments are done. Only then does the fuel bill come down. In the meantime, if you move house, the arrangement passes to the new owner.

In this one you do pay the capital costs. Hopefully you will get a loan, and hopefully the fuel bill reductions will equal the loan repayments, and hopefully you won't want to move house in the meantime.
Now there is nothing wrong with pointing out that the potential savings will cover the outlay, but you could say that about buying double glazed windows, a new bike, LED christmas tree lights or just about anything.
It's not the Pay As You Save scheme though.

quentingargan

recedite wrote: »

OK so the reflectors are perhaps better at harvesting grants than actual solar energy.:D

The other thing here is the FREE idea based on Pay As You Save.
The Pay As You Save scheme is not up and running yet afaik .
In Pay As You Save, you don't pay the capital costs, the utility company does. Then they keep the fuel bills at the previous level until all repayments are done. Only then does the fuel bill come down. In the meantime, if you move house, the arrangement passes to the new owner.

In this one you do pay the capital costs. Hopefully you will get a loan, and hopefully the fuel bill reductions will equal the loan repayments, and hopefully you won't want to move house in the meantime.
Now there is nothing wrong with pointing out that the potential savings will cover the outlay, but you could say that about buying double glazed windows, a new bike, LED christmas tree lights or just about anything.
It's not the Pay As You Save scheme though.

Thanks. Jeff Colley of Construct Ireland Magazine has been doing a lot of pushing for the Pay as you Save concept. It could apply to a lot of energy areas and is a great idea. But I don't know if any of the utility companies have immediate plans to launch this.

I don't think it will take the form you describe though, as ESB for example doesn't know if you replaced your immersion heater with a 52" plasma TV or an electric car. I think the plan would still be to estimate savings and add them to your utility bill.

recedite

Bugnug wrote: »

Gizmo,

Are you sure about those figures? €1000 to €1400 a year on hot water? The price of space heating for the average Irish house is around €1400 to €1600 per annum and water heating equates for approximately 25% of that again. Solar installations cost around €4k to €5k if you take into account disrution and replacement of the cylinder. You would heat a tremendous amount of hot water for that kind of money. I would be more inclined to spend my money on insulation.

And the amount heated by solar is only just over half of that 25%, so lets say €200 per year.
Worst case scenario is payback after 16 years @ €200 per year with a quality system costing €4500 (say €3200 after grants)
That's shorter payback time than they used to quote for getting double glazed windows, which was about 20 years.
Can you imagine anyone who still has single glazed windows now saying, "Yeah I'm glad I didn't get those double glazed windows 20 years ago."

recedite

quentingargan wrote: »

Thanks. Jeff Colley of Construct Ireland Magazine has been doing a lot of pushing for the Pay as you Save concept. It could apply to a lot of energy areas and is a great idea. But I don't know if any of the utility companies have immediate plans to launch this.

I don't think it will take the form you describe though, as ESB for example doesn't know if you replaced your immersion heater with a 52" plasma TV or an electric car. I think the plan would still be to estimate savings and add them to your utility bill.

They won't be going on the meter reading, they will send someone out. They already have the Halo scheme running as a forerunner. They will recommend some upgrades, and if the customer agrees to go ahead, take it from there. They might even get involved in the contract work eventually, who knows?

SOLARTUBE

Not all evacuated tube systems require a heat dump.
The <SNIP> has an integral heat limiter in the top of each tube, this prevents overheating during periods of low occupancy in the property, i.e holidays etc.
Just putting the record straight in case the thoughts of dumping heat would put people of solar. I have a evacuated tube system installed now over 2 years, working a dream, did not do for the cheapest and glad. Lots of hot water during the summer, I do not use immersion to heat the water and my gas bill for the summer was 4 Euro. During winter depending on the day the tank can get to 40deg on a typical day, but on a cold sunny day tank can be satified by solar alone.

Edit: Do not name a Company on post it is against the Charter

quentingargan

SOLARTUBE wrote: »

Not all evacuated tube systems require a heat dump.
The XXXX has an integral heat limiter in the top of each tube, this prevents overheating during periods of low occupancy in the property, i.e holidays etc.

This system relies on a weld between the glass and the copper heat pipe to hold in the vacuum. Where you have two materials with different coefficients of expansion heating and cooling, you may eventually get a loss of vacuum. Keeping the heat within the tube during times of low occupancy etc., exacerbate the problem because they further raise the temperature within the tube.

You won't have a failure at the plumbing end of the system, but you may get failures with the tubes, and I have seen this happen with this type of system in houses where the system regularly over-heated.

As far as I know, the company you name now recommends installing heat dumps with their systems.

Should the vacuum fail with this type of tube, a replacement tube is extremely expensive. Replacement flasks for other systems are mass-produced in numerous factories, all working to the same standard sizes, so replacement flasks are available off the shelf, usually for about €10.

SOLARTUBE

That is not exactly correct.
Yes the company in question does recommend a heat dump on the DF100 model (direct flow) which does not have a limiter, however the HP200 tube does not require a heat dump. Their website and design guide does point the differences out.
I have been involved in solar for over 15 years both Ireland and Internationally and I have yet to see a heat pipe tube with limiter fail due to stagnation occurring in normal usage, nobody would recommend a collector to be left in permanent constinuous stagnation (8 weeks over) but you will agree in a domestic household it is max 3 weeks you would see stagnation.
Also the heat dump you mention only works with power on the building, what happens in a power cut? or the property is between rentals, or unsold, I have seen 100's of systems fail where they have relied on heat dumps, and in all cases the supplier walked away saying the failure was outside their control.

I also believe the manufacturer mentioned has just attained Irish Agrement certification on their product, basically meaning they are the only product that shows compliance with the Irish Building regulations. They are also manufactured in Ireland <SNIP>. The product has been manufactured for over 25 years in ireland and they offer a 10 year warranty. It is the only product sold in Ireland that does not originate in China!!


With regard to the cost of replacemet tubes which is an extremely rare occurance, the typical cost is 25€,

SOLARTUBE

Sorry forgot to mention in my rant that the weld is not between the glass tube and the heat pipe.

The vaccum is sealed using a hermatic seal between the glass and a furrell through which the heat pipe passes through.

It is recognised as being an extremely surperior seal then many of the machanical seals seen on many other vacuum tubes.

On the China tube issue, they all use Borosilicate glass, it is well know that Borosilicate glass is permeable to helium, see the following paper :

Solar Collectors, Energy Storage and Materials : 5 (Solar Heat Technologies)

F. Dewinter, MIT Press (1992) : ISBN 0262041049

It is shown in this paper that Borosilicate glass tube heat losses increase by 20% after 4.5 years and continue to do so.

Good manufacturers use Sodalime glass which is not effected by helium.

Rgds

quentingargan

SOLARTUBE wrote: »

I have been involved in solar for over 15 years both Ireland and Internationally and I have yet to see a heat pipe tube with limiter fail due to stagnation occurring in normal usage

That's funny. I've seen quite a few.

SOLARTUBE wrote: »

Also the heat dump you mention only works with power on the building, what happens in a power cut? or the property is between rentals, or unsold, I have seen 100's of systems fail where they have relied on heat dumps, and in all cases the supplier walked away saying the failure was outside their control.

Really?? Hundreds?? What happens during a power cut is what happens with most systems that have no heat dump. The water goes into the expansion vessel and the system sits in stagnation. This shortens the life of the system, but generally the system should withstand an occasional power cut. In the long term, if allowed to happen regularly, it will degade antifreeze and insulation, but if the system fails on its first stagnation, it is because the expansion vessel was badly set up.

SOLARTUBE wrote: »

It is the only product sold in Ireland that does not originate in China!!

Really? Most of the better flatplate systems come from Austria or elsewhere in mainland Europe. As for the !! bit after China, is this a slur on Chinese quality? The laptop I am typing this on (which is a Japanese brand) is made in China, as are most things these days. China was one of the early adopters of solar water heating and makes a very simple, cheap and effective vacuum flask system which is robust, reliable and affordable.

SOLARTUBE

quentingargan wrote: »

That's funny. I've seen quite a few.


Really?? Hundreds?? What happens during a power cut is what happens with most systems that have no heat dump. The water goes into the expansion vessel and the system sits in stagnation. This shortens the life of the system, but generally the system should withstand an occasional power cut. In the long term, if allowed to happen regularly, it will degade antifreeze and insulation, but if the system fails on its first stagnation, it is because the expansion vessel was badly set up.


Really? Most of the better flatplate systems come from Austria or elsewhere in mainland Europe. As for the !! bit after China, is this a slur on Chinese quality? The laptop I am typing this on (which is a Japanese brand) is made in China, as are most things these days. China was one of the early adopters of solar water heating and makes a very simple, cheap and effective vacuum flask system which is robust, reliable and affordable.

Hi
I am not picking a fight but I have yet to see one hermatic seal product whereby a failure was caused by your explanation.

Yes 100's, all where a heat dump was installed as a solution to stagnation, the temperatures in the system went above 175degC, cracked the propylene glycol and changed the ph from an alkali to an acidic solution and caused damage to the system. As I hope you will be aware, the stagnation is not contained in the vessel alone, continuous thermal shocking of the vessel will cause premature failure. The saftey valve will eventually lift under stagnation, even if the vessel is sized and commissioned correctly, this will allow air to enter the system and increase the likelyhood of stagnation by an airlock in the collector manifold.
Many of the heat dump solutions use a 3 port valve on a simple on/off relay, and in some cases I have found the valve pattern in the worng direction, down to poor supplier information and lack of installer knowledge.
A majority were new houses without occupants and as a result no power.


The reference to China was based on Evacuated tubes and not flat plate, yes there are many very good flat plates manufactured in Europe. I did not infer any slur against Chinese product, but why are so many importers of product into Ireland from China so afraid of being honest and open. Many tube collectors are assembled in Europe with the glass sourced from China, but they balk and dispute the fact the glass comes from China.

I have been to a plant in China (a large supplier of product) and to be fair and no reflection on other companies within China the quality and work conditions were not good. A picture of the same plant was in the Sun Wind Energy magazine a few months back and it was not pretty.
However as with all product it is the manufacturer and not the country of origin that counts.
The difficulty in Ireland is mis-information, lack of knowledge, and mis-selling by some distributors, this will cause a problem for the industry as a whole into the future.

That is why I recommend to all parties interested in solar, to seek out reputable, knowledgeable installers/suppliers with a good track record with good warranties (no less then 10 years) and with site references.

recedite

SOLARTUBE wrote: »

I also believe the manufacturer mentioned has just attained Irish Agrement certification on their product, basically meaning they are the only product that shows compliance with the Irish Building regulations. They are also manufactured in Ireland <SNIP>.

I'm all for supporting Irish industry, but this "monopoly of approval" seems to be raising a few eyebrows. Where does it say in the building regs that all materials must be approved by IAB?
AFAIK all materials are to be fit for purpose and carry a european technical approval, for example the solar keymark.

SOLARTUBE

recedite wrote: »

I'm all for supporting Irish industry, but this "monopoly of approval" seems to be raising a few eyebrows. Where does it say in the building regs that all materials must be approved by IAB?
AFAIK all materials are to be fit for purpose and carry a european technical approval, for example the solar keymark.

I agree, there are other manufacturers going through approval either through IAB or BBA.

The solar keymark is only a performance and collector durability standard but does not take into consideration the system as a whole.
The new requirement for a 60 year deisgn life on in roof collectors does seem unjust, but they are reducing this to 20 years on the basis of easy access.


I do not think monoploy comes into it as the DoE have been accepting 3rd Party Interim certs, but it is probably just a case of first past the post but that will not be the position for much longer With regard to your comments where the standard comes from:

See below extracts:

SEI, Greener Homes Scheme, Phase III, Registered Solar Collector Product List (Introduction)
"It should be noted that the dwellings as a whole, incorporating these products, must comply with all parts of the Building Regulations.
Issues of particular relevance where, for example, roof mounted solar panels are fitted may include: weather tightness, fire safety, structural safety etc. Third party certification bodies eg NSAI/IAB are available to assess compliance with all parts of the Building Regulations."
　
In addition to the above, guidance is also contained in the Floor Area Compliance Certificate Memorandum HA1, Part C, 5.
The relevant extract from H.A.1 (conditions for FACCs) referred to is as
follows:
　
"General Design and Construction Standards
The house/apartment must be of good design providing a suitable living environment for prospective occupants. It must be constructed in accordance with good building practice and in compliance with the requirements of the Building Regulations 1991, including any amendments thereto (hereinafter referred to as the Building Regulations). Where the Technical Guidance Documents, which accompany the Building Regulations, are not followed, compliance with the Regulations must be demonstrated. Where unconventional materials or methods of construction are used, certification by a competent body as to their suitability and compliance with the Building Regulations will be required.
The certification should confirm the suitability and durability of the material/product and method of construction in the context of:-

(a) its use for residential purposes,
(b) the conditions in which it is to be used, and
(c) the climatic conditions pertaining to the location of the
house/apartment.


The real issue is that EN12975 / 76 are not European harmonised standards, also there is no CE mark for solar product, due to this the door is open to requests from the DoE to look for 3rd party competant assesments i.e. IAB Agrement.

There is a new standard coming downstream in 2011/2012 whereby it will be a harmonised standard which will do away from individual market testing requirements.

Hope this helps

recedite

"Third party certification bodies eg NSAI/IAB are available to assess compliance with all parts of the Building Regulations."

That's just a statement of fact from SEIA. They should have specified ;"Third party certification by a body such as NSAI/IAB is required to assess compliance with all parts of the Building Regulations."

I suppose someone will also argue that our climactic conditions are unique and can only be properly certified by IAB.

I still say the building regs issue is only a smokescreen. Compliance is one thing. Certification of compliance is another.

SOLARTUBE

yep you are 100% right
They have required a wind load test is excess of the standard EN12975 due to higher wind velocities.
The real problem is that EN12975 is not a European Harmonised standard, therefore it cannot be used to show compliance with any building regs.
It should be noted that the MCS scheme in the UK is taking the same route and also the French also have their own national requirements.

gizmo555

Bugnug wrote: »

Gizmo,

Are you sure about those figures? €1000 to €1400 a year on hot water?

I'm sure they make no sense, which is the point I was making.

Bugnug wrote: »

I would be more inclined to spend my money on insulation.

I agree 101%!

recedite wrote: »

And the amount heated by solar is only just over half of that 25%, so lets say €200 per year.
Worst case scenario is payback after 16 years @ €200 per year with a quality system costing €4500 (say €3200 after grants)
That's shorter payback time than they used to quote for getting double glazed windows, which was about 20 years.
Can you imagine anyone who still has single glazed windows now saying, "Yeah I'm glad I didn't get those double glazed windows 20 years ago."

A major difference between double glazing and a solar hot water system is that the double glazing not only saves energy, but makes the house more comfortable by helping to maintain a more even temperature and making it faster to warm up when the heating comes on. Depending on location, it may also reduce street/traffic noise. Assuming one can already get all the hot water one needs one way or another, whether from electricity, oil, etc., solar adds nothing to the comfort of the house.

saibhne

SOLARTUBE wrote: »

On the China tube issue, they all use Borosilicate glass, it is well know that Borosilicate glass is permeable to helium, see the following paper :

Solar Collectors, Energy Storage and Materials : 5 (Solar Heat Technologies)

F. Dewinter, MIT Press (1992) : ISBN 0262041049

It is shown in this paper that Borosilicate glass tube heat losses increase by 20% after 4.5 years and continue to do so.

Good manufacturers use Sodalime glass which is not effected by helium.

Rgds

Two things on this - the paper listed above is actually a book which costs Euro 120 to buy - it's hard to verify what you are saying on this issue by using this reference. Also when citing a book it would be good to indicate the page no. you are referencing. I am sceptical about this information for this reason and also for the fact that the research must have occurred in the 80s more than 20 years ago.. I keep an open mind but would need more persuausion on this.

Secondly you mention that good manufacturers use sodalime glass but the supplier in question also uses borosilicate glass on their DF range of panels. Link It seems strange that they would persist with this if it is such a bad idea..

quentingargan

SOLARTUBE wrote: »

On the China tube issue, they all use Borosilicate glass, it is well know that Borosilicate glass is permeable to helium, see the following paper :

Solar Collectors, Energy Storage and Materials : 5 (Solar Heat Technologies)

F. Dewinter, MIT Press (1992) : ISBN 0262041049

It is shown in this paper that Borosilicate glass tube heat losses increase by 20% after 4.5 years and continue to do so.

The "company's" selective use of that reference is a pretty poor show. First of all, this figure was based on a theoretical equation, not an actual test. Secondly, the VERY NEXT SENTENCE after the 20% one that you selectively quote says "The envelope of evacuated collectors .... generally operates at much lower temperatures and would be less vulnerable to helium penetration”. (see extract from book reproduced below).

An actual test of borosilicate glass shows that in fact after 6 months at a steady 300 degrees centigrade, the efficiency was reduced by 2%. See here

yuloni

This post has been deleted.

Turbo33

Hi,

I have thinking of getting a solar solution ( new to this also and learning ) and most likely the vacuum tube type as they appear more effecient and easy to replace the tubes if damaged etc. I assume anyone can buy these tubes as replacements and they are standard type fittings i.e. easy enough to replace.

Just wondering is there any advantage to having a dual pump station and control unit over a single line pump station and control unit? Anyone know?

thanks
T.

quentingargan

Turbo33 wrote: »

Hi,

I have thinking of getting a solar solution ( new to this also and learning ) and most likely the vacuum tube type as they appear more effecient and easy to replace the tubes if damaged etc. I assume anyone can buy these tubes as replacements and they are standard type fittings i.e. easy enough to replace.

Just wondering is there any advantage to having a dual pump station and control unit over a single line pump station and control unit? Anyone know?

thanks
T.

The tubes are easy enough to replace. The Chinese type, which is a single glass flask, is generally easier and cheaper to replace. If the tube is either 47mm or 58mm in diameter, it is a fairly standard size which you could buy from any number of suppliers. Other sizes tend to be more proprietary.

The twin-line pump station includes an air vent, and may have some slight benefits in certain situations, but generally the single line is commonly used, and easier to fit as well. I personally prefer to get the pump station separate from the controller and put the controller somewhere more convenient than at the back of the hotpress. It is your only means of knowing how hot the water in your cylinder is, so stick it somewhere handy:)

SOLARTUBE

saibhne wrote: »

Two things on this - the paper listed above is actually a book which costs Euro 120 to buy - it's hard to verify what you are saying on this issue by using this reference. Also when citing a book it would be good to indicate the page no. you are referencing. I am sceptical about this information for this reason and also for the fact that the research must have occurred in the 80s more than 20 years ago.. I keep an open mind but would need more persuausion on this.

Secondly you mention that good manufacturers use sodalime glass but the supplier in question also uses borosilicate glass on their DF range of panels. Link It seems strange that they would persist with this if it is such a bad idea..

The DF product does not use Borosilicate, they switched to Sodalime many years ago, there is an updated cert which corrects the comment, see ISFH report 108-06/Q3 dated 09/03/2009

yuloni

This post has been deleted.

quentingargan

SOLARTUBE wrote: »

The DF product does not use Borosilicate, they switched to Sodalime many years ago, there is an updated cert which corrects the comment, see ISFH report 108-06/Q3 dated 09/03/2009

So this company used to use borosilicate, but has since mended its ways, seen the light and switched to soda lime glass? Or maybe it just switched to soda lime glass (which after all, is a bit cheaper) and has seen a marketing opporunity by mis-quoting a textbook.

The most disturbing bit of your post , and it concurs with claims I have seen on the web, is a pathetic attempt to discredit the use of borosilicate glass.

I find it unbelievable that a company working in what would be perceived as a very ethical industry, could selectively extract a single line from a textbook which theorises that borosilicate might lose efficiency, and then ignore the very next sentence which disputes such a conclusion.

People are confused enough about various types of solar panels without being subjected to this sort of nonsense.:mad:

starfish12

An earlier post mentioned the ESB HALO scheme, are they now involved in solar panels? It doesnt say so on their website? am just wondering as am also interested in installing solar, but most of the companies offering seem v.dodgy from the outset! timber frames houses last year, solar this year, who knows what next year, what happens in 2-3 years time if they malfunction etc?

Turbo33

Hi,

Sorry for the silly question but i am a noobie to solar panels... Just to be clear from a performance point of view there is no major difference between the two types of solution in Glass i.e. Soda-Lime glass versus borosilicate glass?

I got this from wikipedia under Solar thermal collector....

"
Soda-lime glass is used in the higher quality evacuated tubes manufacture. Newer technology evacuated tube systems use a coated glass-and-metal absorber. The glass is a boron silicate material and the aluminum absorber plate and copper heat pipe are slid down inside the open top end of the tube. In lower quality systems moisture can enter the manifold around the sheet metal casing, and may eventually be absorbed by the glass fibre insulation and finds its way down into the tubes. This can lead to corrosion at the absorber/heat pipe interface area or freezing ruptures of the tube itself if the tube absorbs water.
"

I am a bit confused...Does this article from wikipedia say that the boron silicate is the newer and better choice?

cheers
T.

quentingargan

starfish12 wrote: »

An earlier post mentioned the ESB HALO scheme, are they now involved in solar panels? It doesnt say so on their website? am just wondering as am also interested in installing solar, but most of the companies offering seem v.dodgy from the outset! timber frames houses last year, solar this year, who knows what next year, what happens in 2-3 years time if they malfunction etc?

ESB invited companies on the SEI list to quote for both product supply and installation. AFAIK, that tendering process is still going on.

I would say that there are very few dodgy companies in this industry, and I wouldn't like my last post to be taken as implying that any company referred to was "dodgy" as such, just has an over-exuberent marketing employee who slightly lost their way.

There are a few entrants to the market whose sales techniques are reminiscent of double glazing a few years back - I've come across a few people who were bamboozled into signing contracts by one particular operator, a forged TUV certificate from a second operator, and a couple of other operators whose practices I would call into question, but that is out of quite a pool of suppliers. The usual caution is needed. Despite the presence of cowboys, there is still a buoyant second-hand car market:rolleyes:.