Solar Panels - Yes or No

Eve2008

Hi All,

Im currently at roofing stage of myself build project and Im wondering if I should install solar panels.

The panels are costing in the region of about 5K. Im istalling an oil fired central heating system as well as a stove (with back boiler) and Im wondering if its worth spending money on the solar panels given the heating system that Im installing? Will this be money well spent?

Kevin007

Hi there
Why are you fitting a stove ? The best of the Solar panels are the glass tube type also known as Evacuated Tubes They pick up more heat and Heat water to higher temperature than the junk models made of copper tubing with aluminium fins There are at least 6 distributers of the good ones around Go 4 them. One of them is a crowd called Ecologics somewhere in Wickla Best of Luck

Eve2008

Thanks Kevin007.

Im putting in the stove as an alternative to the oil heating. The stove im installing will be capable of heating some of the rads in the house.

As the solar panels would have to be installed on the front of the hse I was going to install the flat panel. Do you think im wasting money installing the panels given my choice of heating system?

Kevin007

Hi again
The question is why do you want to fit an inefficient stove to back up an efficient oil system unless you like the idea of curling up in front of a fire
The efficiency of a stove at 40% efficiency cannot compare to the greater efficiency 80% of an oil boiler especially if it's a good one and properly designed. Stoves therefore are a luxury and not a practical solution to energy generation unless as I said b4 you just ' like ' them or have a ready source of very very cheap fuel. Ask your solar supplier what the payback is his panels In otherwords how long will it take you to get your money back onthe panels The performance of Evac Tubes is as good as is going as long as you have a need for 300 litres of Tepid water every day( 40Deg.C ) Regards K007

muffler

This will probably be better off in the RE forum.

Moved.

CJhaughey

Kevin007 wrote: »

Hi there
Why are you fitting a stove ? The best of the Solar panels are the glass tube type also known as Evacuated Tubes They pick up more heat and Heat water to higher temperature than the junk models made of copper tubing with aluminium fins There are at least 6 distributers of the good ones around Go 4 them. One of them is a crowd called Ecologics somewhere in Wickla Best of Luck

With all due respect Kevin, you are talking out of your hat if you say that all evacuated tubes are better then flat panels.
Flat panels are certainly not in the category of "junk".
This has been covered before here and I am not going to repeat it but there is a lot of evidence from various sources that flat panels are actually more efficient then evac tubes.

Eurorunner

How is stove efficiency 40%? Having gone through the process of purchasing one recently, I checked out a number of models from different manufacturers and they were all checking out with an efficiency level of 70-75%. Bear in mind also the capital cost is so much cheaper than outlay for solar. Although, ideally it really only suits someone that has access to a regular and relatively cheap source of solid fuel.
As regards Solar, I remain a sceptic. Whats the expected lifespan of the panels themselves before they need to be replaced??

Eurorunner

Eurorunner wrote: »

As regards Solar, I remain a sceptic. Whats the expected lifespan of the panels themselves before they need to be replaced??

I would suspect that flat solar panels, if well constructed should last as long as the roof! I don't know about the life expectancy of tubes - but they are fragile compared to flat panels.

The other thing to remember of course is that you need to replace other fuel boilers as well after a while.

Squints

Hi eve,
Just afew questions..
What area of solar do you intend to install? General rule of thumb is 1.5m2 4 each person in the household and 50-70 litres of hot water storage capacity for each person. Every installation can be designed to be effecient and cost saving regardless of current heating system if designed good.
Also flat panel collectors are no heap of junk. Evacuated tubes transfer heat at the same temperature as flat panel collectors, there benefit is they are more efficient at times when they sun is not directly above them as they are cylinderical. So you should evacuated if your roof is not directly south facing. Most flat collectors and evacuated tubes have guarantees of between 15-25 years.

Dr. Nick

deleted

homer911

Kevin007 wrote: »

Hi again
The performance of Evac Tubes is as good as is going as long as you have a need for 300 litres of Tepid water every day( 40Deg.C ) Regards K007

???

I've got 300l of water up to 85C on occasions with 4sqm of tubes.
Summer typically averages 60C

copper12

Eve2008 wrote: »

Hi All,

Im currently at roofing stage of myself build project and Im wondering if I should install solar panels.

The panels are costing in the region of about 5K. Im istalling an oil fired central heating system as well as a stove (with back boiler) and Im wondering if its worth spending money on the solar panels given the heating system that Im installing? Will this be money well spent?

Im currently at roofing stage of myself build project and Im wondering if I should install solar panels.
If you are at this stage, then the stove and the boiler are already fitted ?
If you are unsure about fitting the panels; then you can at least run the pipe work; and fit a three coil cylinder .
It’s better to be looking at it; than looking for it
If the wood is free, then I would consider leaving them out, as the cost would be to great

baldieman

Hi, The advantage of the stove, in my view, is your not dependent on one or the other fuel.
As for the solar, the system works and it could take 12 -15 years to pay back.
But once installed, the clock starts ticking. You're getting free hot water.
Although property values are poor at the moment, it should add that value on to your home. It will improve your energy rating for any future sale. As for which system, I prefare the tube, they ARE more efficient and while they can break down, they're not expensive and are easy to replace.

mad m

homer911 wrote: »

???

I've got 300l of water up to 85C on occasions with 4sqm of tubes.
Summer typically averages 60C

What are you getting lately? Mine was up to around 40c the other day...

ardara1

Stove in fore place means big fire, wine and the possibility of a Santa arrivin' 25th Dec. - don't knock it.

Solar - will gove you possibly 50% of your hot water requirement over the year (But mostly i Summer when you need cold showers! - but put them in.

Link the wood stove up to the tank - and when you're enjoying the wine in front of a roaring fire - the jacuzzi will be ready for later. Just leave the door open 24th.

CJhaughey

baldieman wrote: »

As for which system, I prefare the tube, they ARE more efficient and while they can break down, they're not expensive and are easy to replace.

That all depends on which tubes you buy and compared with which flat plate collector you have.
Plenty of shyte chinese tubes around, and conversely plenty of good chinese tubes around.
Do research before you buy, what is the manufacturers name? Are the collectors tested? What rating have they got?
Don't make the mistake of believing that all tubes are better than flat plates.
There are lots of good flat plate manufacturers in Europe with high efficiency panels, that are better than many tubes.
Tubes can be replaced, as long as the maufacturer still exists and the importer still brings them in....

RKQ

baldieman wrote: »

Hi, The advantage of the stove, in my view, is your not dependent on one or the other fuel.
As for the solar, the system works and it could take 12 -15 years to pay back.

I agree with baldieman, ardara1 and CJ.
If you like an open fire, then a stove is a more efficient way of having one. Don't knock the soothing relaxation of flickering warm flames. We have used Fire since we were in caves.

Triple coil cylinders are expensive but are worth the investiment. At least put in the piping for future use. The price of Oil will continue to rise in the future.

Providing an eco-element to your house is a requirement of the new building regulations. So . If you don't have a solar panel you may well be perceived as "old hat" or "outdated" in afew years time!

homer911

mad m wrote: »

What are you getting lately? Mine was up to around 40c the other day...

Right now its 42C

Mine os 46C right now and the panel is 55C

mad m

homer911 wrote: »

Right now its 42C

Thanks for that, I was getting paranoid with temps... I have 3 solar windhager intergrated flat panels with 300litre stainless steel dual coil cylinder..

baldieman

CJhaughey wrote: »

That all depends on which tubes you buy and compared with which flat plate collector you have.
Plenty of shyte chinese tubes around, and conversely plenty of good chinese tubes around.
Do research before you buy, what is the manufacturers name? Are the collectors tested? What rating have they got?
Don't make the mistake of believing that all tubes are better than flat plates.
There are lots of good flat plate manufacturers in Europe with high efficiency panels, that are better than many tubes.
Tubes can be replaced, as long as the maufacturer still exists and the importer still brings them in....

I agree, there are some dodgey tubes about and yes, making sure the spares are available. A box of spare tubes might be a good idea. (the tubes themselves are not that expensive.) The heat pipe system is the simplest to install. Other then the issue of getting up to the panel, two minutes would replace a tube, no tools needed. (the heat pipe tube has no liquid moving through it) no plumbing involved. The main reason,in my opinion, the tube is more efficient is low angle sun hitting a circular object is more likely to hit perpendicular and therefore penetrate compared to even the best flat panel. Low angle rays will hit the surface like a skimming stone on a lake.

Kevin007

Hi again
My comment on junk solar panels refers as I said firstly refers to models made of aluminium and copper tubing and this still holds. I have access to a test rig where every type of Solar panels can be tested accurately and yes there used be very good flat solar panels available but lately there are low grade panels available which will work well enough in Meditaranean climates but not so in Ireland in the off Summer season. The performance of Evac panels shows better outputs in the 'cooler' times of the year and this can show outputs some 50% greater than the the low grade units

iamlegend2008

Hi

Some of the previous posters make mention of checking whether the collectors are good ones but Im not sure how to check this. My plumber is recommending calpak collectors from RVR. This is registered on the SEI site but Im unsure how to check the rating for this model. I would appreciate if someone could PM me with their view of these collectors.

Thanks.

Kevin007

Hi
Being on the SEI List is not a recommendation as to the quality of product
Will try to get some info 4u on the RVR. They are a good Co. With lots of good product but can be expensive especially on service

baldieman

iamlegend2008 wrote: »

Hi

Some of the previous posters make mention of checking whether the collectors are good ones but Im not sure how to check this. My plumber is recommending calpak collectors from RVR. This is registered on the SEI site but Im unsure how to check the rating for this model. I would appreciate if someone could PM me with their view of these collectors.

Thanks.

Are they European? they look pretty good. How expensive? If your plumber has already used these, could you ask for some previous clients phone no's?
The product is one thing, how good a job the plumber does is another!

cabbott

i too am at roofing stage:D, and was considering solar palels, and was talked out of it by someone who sells pellet/timber boilers, he told me to give it a couple of years and there will be a new generation of pv (electric) panels available which will run an imersion, see how they go and then decide. im glad i didnt purchase now because my mother since got 2 panels in, i dont know what make, and the system leaves me unimpressed:(. granted the panels are about 45 ft away from the cylinder so it will take some time just to heat up the water in the feed pipes, plus there is the running cost of the pump which goes a lot of the time when there are little gains in cylinder temperature. over all in my opinion, big outlay, slow repayment, not completely free, and some luke warm showers:mad: when i expected them to be in some way hot. now that the heating is on in the evenings there is always very hot water there and the solar would never raise the temperature of the water above what it is.

Mossyfields

A correctly sized, solar system fitted during construction should pay back within 7 years ( at current fuel prices). I retrofitted an evacuated tube system during the summer. They are working great , a constant supply of hot water. The pay back time on my system will be under 10 years... I agree the stove is a good idea, the efficiency is better than an open grate , but is not 70%.

Gtec

calpak collectors from RVR.

I have 2 of these and they work fine in my opinion. I have full time monitoring on the system which is available to view on the web. PM me if you want a link to it (it's on a commercial site so i can't post here)

For me the fact that I only needed to add heat to the hot water on a handful of days between paddy's day and the end of September means the system works. Actual payback is a very different issue - it totally depends on the cost of the fuel on the day you buy / use it - compare the difference in the payback calculations from July when crude oil was over $150 a barrel and everyone was talking about it hitting $200, and today when it is (and I just checked;-)) $64 a barrel. I know we don't feed our houses on barrels of crude oil, but the cost of energy is at least loosely related to this cost.

I'm a believer, for me put them in now, while you have plumbers and roofer on site anyway. taking the logical extension of the other advice here which was to put in the triple coil cylinder and the pipe work, add the €1700 for 2 panels and fit them now.


Gtec

Eurorunner

Mossyfields wrote: »

I agree the stove is a good idea, the efficiency is better than an open grate , but is not 70%.

Not disputing this but if this is the case, is there any independent info out there confirming what % efficiency a stove offers? All the stove manufacturers are claiming 70-75%

Gtec wrote:

Actual payback is a very different issue - it totally depends on the cost of the fuel on the day you buy / use it

Had you worked out the payback based on the higher figure (lets face it, we will go back to that point once the markets recover) and if so, how many years was it?

Gtec

Had you worked out the payback based on the higher figure

No I never worked out the payback figure. The situation I found myself in was the imersion in the existing cylinder was gone, and the cylinder was leaking due to hard water damage. faced with having to replace the cylinder anyway, I opted for a solar system. To me the decision was partly eco, partly a wish to reduce the running costs of my house because I want to be able to retire early.

I did try to do payback calculations, but the reality is that I have absolutly no idea how much hot water I was using, nor what proportion of my anual bills went to heating water, without knowing how much I was spending I cannot calculate how much I am saving. There are just too many variable to get a good picture.

Gtec

copper12

mossy fields as you say; correctly sized and installed.
90 feet of pipe work; between tank and panels?
Lukewarm water
Pump running if there no heat gain
The above is unfortunately true, about a lot of systems, that cost a lot to install
The solar; will only be of benefit’ during the summer in this case
But probably a lot cheaper to fit them now than later
The cost of the solar would have to be compared to the free heat from the stove
This would make the pay back time take a lot longer

yop

Good reading lads, anyone installed the panels themselves?

I am wondering also if there is any point in my installing panels along with my DX geothermal system? I have a 500 litre tank installed as I am so it would need to be piped in there, but I am wondering now if anyone has done this?

copper12

Since the major cost in your system; is the cost of electricity
I would think it would be of more use to you; than others; that is if you use your dx system.
for hot water, in the summer, properly designed, and installed, preferably with a solar panel’ to run the pump, keeping the running cost to a minimal, then I could see the justification of installing solar

Mossyfields

A personal opinion....... geothermal should never be used to heat anything other than space heating. I have listened to sales guys telling how brilliant their system is but they will not tell you the high running costs.... A personal opinion.........geothermal should never be used for heating radiators but only for underfloor heating. Geothermal is very economic to run if it is used correctly , unfortunately it is missold and missused. To achieve tempratured above 30 degrees a heat pump looses it co-efficiency and the electricity costs become excessive. Getting heat from a geothermal source is like getting juice from an orange. Its easy to get the first half cup of juice..... but you have to use a lot of energy and muscle to fill the cup...... likewise getting heat from geothermal. Install solar panels for hot water........ turn off your heat pump during the summer months....... I believe ground source geothermal is the msot efficient method to heat your home....

copper12

A personal opinion........ I think your right

yop

Just to give an idea of our setup, we are using a heatplate/immersion for on demand hot water so the main heating is for the UFH, I have kept the loops of our UFH as tight as possible there for reducing the running temperature in the loops.

Based on readings I have taken we are running our geothermal system including all the hot water for between 500 and 600 euro per year.

I am seriously considering the solar panels also. One thing that does puzzle me though is that the installer, who also does solar, did not recommend them, he said that there would be no major benefit. Which is odd do you think?

Mossyfields

It does seem odd to me.. The only thing that comes to mind is, when he was quoting for the origional work he was trying to keep the cost down to win the contract.

May I ask, do you run your heat pump on night rate electricity ?

yop

Its on night ya Mossy. It is odd for sure, in fairness to the installers they were as neat at their work as I ever seen and came back to me within 24hrs when I had an issue 6 months later.

I must ring him and ask him again why he did not recommend it.

What do you lads honestly think?