Are you all pleased with your solar panels for hot water heating

John T Carroll · 19-10-2012 8:44pm

Roundtd181 wrote: »

Just a rant here. see people have been putting in the Chinese tubes that Kingspan are buying and selling as part of their kit, i hear they are of very poor quality and there is a lot less output in heat compared to other panels like the Solarfocus.

Anybody know anything about Worcestor Bosch?
What about swedish/norwegian/icelandic panels, i would be interested ins talking to a supplier for them.

At the minute i am going with 2 flat plate solar panels with a new 350litre Maxipod tank unless can be convinced otherwise!!

As a Flat Plate user, I would consider 2 Flat plates + a 350 litre Cyliner as grossly underpowered. I even consider the ubiquitous 3 Flat plates + 300 litre Cylinder as underpowered. A Flat Plate Collector will rarely stagnate especially if you set the Max Cylinder Temperature at 80C. The highest cylinder temperature observed on my system was 76.5C with little or no usage and on inhibiting the solar circ pump,the max collector temperature observed was 110C.
I would consider 4 Flat Plates as the minimum for a 350 litre Cylinder and even 5 (10M2) might not be outrageous. The Cylinder looses 0.3C to 0.5C per hour, with say 15 hours between "solar periods" at night, the cylinder will loose 4.5C overnight....nor alot, but this is over 1.8 KWH which must be made up one way or the other to get back to where you were the previous evening. An extra Flat Plate will take care of this with a good bit to spare for useful heat input. My system has 150/4, or 37.5 litres/M2 of collector.
350 litres with 4 Flat plates (8M2) gives 350/8, or 43.75 litres/M2. 350 litres with 5 Flat Plates (10M2) gives 350/10, or 35 litres/M2.

dathi · 20-10-2012 12:08pm

hi roundtd the simplest way of comparing solar collectors is to use the heatloss data and the optical efficiency data . the heatloss data refers to the amount of heat that the panel reflects back to the air around it, and it is shown in two numbers a1 and a2, these should be as low as possible . the optical efficiency/conversion data should be as high as possible as the higher it is the better it is at converting light into heat. had a look at your solarfocus and the figures they give are as follows .heatloss a1(they called it k1)(3.3 ) a2 (0.012) optical efficiency /conversion 0.74 just looked at some sites to compare it so the following is a flat plat from rvr a1 (3.26) a2(0.016 ) optical(0.745) so as you can see the out puts are fairly similar for the two flat plates. the out puts for thermomax hp400 are a1(1.18) a2 (0.0095) optical(0.75)so the output per m2 is very similar but as it is a tube system it looses much less heat to the air so will work better in spring or summer.and finally wimex tubes (Chinese) a1(1.34) a2(0.0101) optical (0.61) so from these figures thermomax is 14%more efficient at turning light into heat than these Chinese tubes but if you have the space for extra tubes the cost may favor the Chinese system hope this helps

John T Carroll · 20-10-2012 2:49pm

dathi wrote: »

hi roundtd the simplest way of comparing solar collectors is to use the heatloss data and the optical efficiency data . the heatloss data refers to the amount of heat that the panel reflects back to the air around it, and it is shown in two numbers a1 and a2, these should be as low as possible . the optical efficiency/conversion data should be as high as possible as the higher it is the better it is at converting light into heat. had a look at your solarfocus and the figures they give are as follows .heatloss a1(they called it k1)(3.3 ) a2 (0.012) optical efficiency /conversion 0.74 just looked at some sites to compare it so the following is a flat plat from rvr a1 (3.26) a2(0.016 ) optical(0.745) so as you can see the out puts are fairly similar for the two flat plates. the out puts for thermomax hp400 are a1(1.18) a2 (0.0095) optical(0.75)so the output per m2 is very similar but as it is a tube system it looses much less heat to the air so will work better in spring or summer.and finally wimex tubes (Chinese) a1(1.34) a2(0.0101) optical (0.61) so from these figures thermomax is 14%more efficient at turning light into heat than these Chinese tubes but if you have the space for extra tubes the cost may favor the Chinese system hope this helps

In fairness to Solarfocus, their claim to superior (F.Plate) performance is based on the fact that their panels are fitted with a "Cylindrical Aluminium Reflector" which passively tracks the sun and is akin to the "Compound Parabolic Concentrator" or CPC fitted to some evacuated tubes. It will/should give better performance than the "standard" Flat Plate. A company called Genersys were are? making a Flat Plate that is vacuum sealed, has anyone out there got them?. JTC

championc · 20-10-2012 3:16pm

Can your installer not give you any data from a real live working system ? You can never argue with live data.

John T Carroll · 20-10-2012 4:49pm

dathi wrote: »

hi roundtd the simplest way of comparing solar collectors is to use the heatloss data and the optical efficiency data . the heatloss data refers to the amount of heat that the panel reflects back to the air around it, and it is shown in two numbers a1 and a2, these should be as low as possible . the optical efficiency/conversion data should be as high as possible as the higher it is the better it is at converting light into heat. had a look at your solarfocus and the figures they give are as follows .heatloss a1(they called it k1)(3.3 ) a2 (0.012) optical efficiency /conversion 0.74 just looked at some sites to compare it so the following is a flat plat from rvr a1 (3.26) a2(0.016 ) optical(0.745) so as you can see the out puts are fairly similar for the two flat plates. the out puts for thermomax hp400 are a1(1.18) a2 (0.0095) optical(0.75)so the output per m2 is very similar but as it is a tube system it looses much less heat to the air so will work better in spring or summer.and finally wimex tubes (Chinese) a1(1.34) a2(0.0101) optical (0.61) so from these figures thermomax is 14%more efficient at turning light into heat than these Chinese tubes but if you have the space for extra tubes the cost may favor the Chinese system hope this helps

The attached simple SpreadSheet may be a help in comparing these efficiencies.

John T Carroll · 21-10-2012 9:35am

championc wrote: »

Can your installer not give you any data from a real live working system ? You can never argue with live data.

Some data here from a UK government report but includes some Irish sites.

Roundtd181 · 22-10-2012 9:40am

Some great Info there lads. Getting some great feedback. John T im near sure Genersy's are based in Co.Down.

John T Carroll · 23-10-2012 4:24pm

Roundtd181 wrote: »

Some great Info there lads. Getting some great feedback. John T im near sure Genersy's are based in Co.Down.

Thanks for that Roundtd, can someone please tell me what the Kingspan SC 100 Controller is in Steca? form.

freddyuk · 27-11-2012 5:42pm

Sun!!! We had 60c at the tubes and got 54c top and 53c bottom into the 200l cylinder today. Starting point was 38c.:D

Qualitymark · 27-11-2012 6:06pm

freddyuk wrote: »

Sun!!! We had 60c at the tubes and got 54c top and 53c bottom into the 200l cylinder today. Starting point was 38c.:D

Wow! And today was *icy*!

sas · 28-11-2012 11:33am

Qualitymark wrote: »

Wow! And today was *icy*!

Solar panels are more dependent on light than heat.

On mild damp grey days this time of year I literally get nothing from my array.

The best possible weather at the moment is clear blue skies, regardless of the actual outside temps.

I've a 1000litre tank.
Yesterday morning when I left the bottom 20 and the middle was 52. I've no stat at the top so no reading for there.
When I got home the bottom was 46 and the middle was 56.

We were able to run our UFH yesterday evening directly off the tank i.e. solar heated ufh. It doesn't happen very often but it was great that conditions let us do this every so often.

Qualitymark · 28-11-2012 11:35am

sas wrote: »

Solar panels are more dependent on light than heat.

<snippety>

We were able to run our UFH yesterday evening directly off the tank i.e. solar heated ufh. It doesn't happen very often but it was great that conditions let us do this every so often.

UFH?

sas · 28-11-2012 12:19pm

Qualitymark wrote: »

UFH?

Under floor heating

Qualitymark · 28-11-2012 3:19pm

sas wrote: »

Under floor heating

Envyyyyyyyyy!!!

sas · 28-11-2012 4:26pm

Qualitymark wrote: »

Envyyyyyyyyy!!!

Yeah, I wouldn't get too upset. My solar set up cost me OOohhhh so much more than it should have. The system (and I) will have to still be around in 2100 for it to break even.

You live and learn I suppose.

dathi · 28-11-2012 4:58pm

30 tubes into 200ltrs collector temp was -2 this morning at 9am tank was 18 btm 23top this evening 42 top and btm

Qualitymark · 28-11-2012 5:46pm

sas wrote: »

Yeah, I wouldn't get too upset. My solar set up cost me OOohhhh so much more than it should have. The system (and I) will have to still be around in 2100 for it to break even.

You live and learn I suppose.

What would you do if you were doing it now?

sas · 28-11-2012 6:38pm

Qualitymark wrote: »

What would you do if you were doing it now?

Note: My house is passive so my needs are pretty minimal

2 options:

1. Get an air source heat pump and use that for everything. Currently I have oil and solar. This could give me an issue with building reg compliance!

2. Purchase solar tubes but import directly the cheapest possible chinese tubes that I can find. I know someone who did this and he spent 1/4 on his tubes compared to what I spent. While they likely won't offer the same performance as mine, they sure as hell aren't offering 1/4 the performance either.

dathi · 28-11-2012 6:56pm

on paper my Chinese tubes are 14% less efficient than thermo but were considerable more than 14% cheaper

sas · 28-11-2012 7:05pm

dathi wrote: »

on paper my Chinese tubes are 14% less efficient than thermo but were considerable more than 14% cheaper

Yeah, there you go.

Qualitymark · 28-11-2012 11:39pm

sas wrote: »

1. Get an air source heat pump and use that for everything. Currently I have oil and solar. This could give me an issue with building reg compliance!

a) What's an air source heat pump?

b) Why would having it, oil & solar give you trouble with building compliance?

sas · 29-11-2012 11:12am

Qualitymark wrote: »

a) What's an air source heat pump?

b) Why would having it, oil & solar give you trouble with building compliance?

Google will answer a) for you much better than I can.

I was suggesting that I would only have an ASHP, not also with the oil and solar. There is a requirements under Part L of the regs to get a certain % of your energy through renewables. This can be tricky in a low evergy home. I "might" have a problem is simply what I was attempting to state.

freddyuk · 01-12-2012 8:04am

I thought it may be useful to see in real time what a simple thermal system will achieve in depths of winter in Ireland. Here is an image of my flow side gauge and the weather outside which was about to rain (yesterday morning).
The incoming water to my cylinder at 30+c is going to give the boiler less to do to get it to 55c than normal mains incoming water at 10-12c.
I do not think the ambient temperature has that much influence as there is so little water in the roof part of the system. There is certainly no direct sunlight.
http://i1145.photobucket.com/albums/o517/freddyuk1/IMG_0879.jpg
http://i1145.photobucket.com/albums/o517/freddyuk1/IMG_0876.jpg

jakko86 · 02-02-2013 12:06pm

Hi was just a quick question I was looking at a roof last week and the solar panels were all condensation? I presume this is bad or why would this happen??

jdrysdale · 03-02-2013 5:10pm

sinnerboy wrote: »

I'll sticky this awhile and add

Please indicate

.

cost 2000 euro ish
year of installation 2006
m2 area 1.2
orientation south
flat plate or tubes tubes
cylinder size 120
summer heat dump strategy ( if any ) three way valve to radiator

Upgraded to 2 sq metres with overhaul upgrade of tubes. Performance was adequete but declining, now excellent, upgrade cost about two hundred euro with a good bit of elbow grease.

Qualitymark · 04-02-2013 12:50am

jdrysdale wrote: »

cost 2000 euro ish
year of installation 2006
m2 area 1.2
orientation south
flat plate or tubes tubes
cylinder size 120
summer heat dump strategy ( if any ) three way valve to radiator

Upgraded to 2 sq metres with overhaul upgrade of tubes. Performance was adequete but declining, now excellent, upgrade cost about two hundred euro with a good bit of elbow grease.

Does that include getting someone to instal the panels, plumbing and immersion, or did you do that work yourself?

And what kind of heat are you getting at different times of year?

jdrysdale · 04-02-2013 8:37am

Qualitymark wrote: »

Does that include getting someone to instal the panels, plumbing and immersion, or did you do that work yourself?

And what kind of heat are you getting at different times of year?

I did all the install but had to pay a plumber to sign off on the install. I had being getting satisfactory hot water between April and sept when central heating is off. Although 2012 was not great.
Hoping for a better performance this year and the indication is good so far.

quentingargan · 04-02-2013 9:10am

dathi wrote: »

on paper my Chinese tubes are 14% less efficient than thermo but were considerable more than 14% cheaper

Often the "on paper" figures don't include incidence angle modification" or IAM. The Chinese tubes are better on this than flatplates within a tube type systems.

lainatro · 21-02-2013 2:47pm

any comments on thermomax??

championc · 21-02-2013 7:34pm

lainatro wrote: »

any comments on thermomax??

Read through the thread

07-06-2013 2:40pm

Nice weather for it

championc · 07-06-2013 3:01pm

If your system is not up to max temperature at this stage after these continuous days of sunshine, then your system has a serious issue. My whole tank was at 80 deg C yesterday afternoon. So it's MAX'ed out now.

C

07-06-2013 3:44pm

No temperature probe at the top of the tank but temp. at base of tank >70degrees, <75 degrees for the past while, boiler hasn't fired in about a month and if anything DHW usage has increased.
Internal room temperatures have been hanging out at 22 to 25 degrees for the past while also, it's all good.

Qualitymark · 07-06-2013 3:52pm

Fellow came to the door offering solar panels to heat radiators, for €9k-€13k; when I queried this (and his claim of a five-year payback) he said they used a "new chemical". No brochure, no identification of the "new chemical"....!

John T Carroll · 07-06-2013 3:59pm

championc wrote: »

If your system is not up to max temperature at this stage after these continuous days of sunshine, then your system has a serious issue. My whole tank was at 80 deg C yesterday afternoon. So it's MAX'ed out now.

C

Just saw the post(s) on my EMail, Championc, the circ pump seems to have stopped with the following temperatures....Roof:83C. Bott.Buff:74C. Mid.Buff:75C. Top.Buff:75C. Have you lowered your max cylinder temperature to allow this to happen? or is there another reason?....I didnt see your trends yesterday but if the whole tank went to 80C yesterday then it should attempt to do likewise today?......John

championc · 07-06-2013 5:18pm

Hi John

I actually had it set to max at 85 so I've reduced it to 75 since plenty of water was being released via whatever safety valves are in the setup and so plenty dripping out from the vent pipe.

The whole store went to 85 yesterday so 75 seemed more sensible. However, I think you saw the data John just when the pump was knocking off because the roof temperature naturally shot up and has been in the mid 150's deg C for the past hour !! The sun has now passed over and it's reducing. But hey, it's a Kingspan system and the Kingspan is designed to auto-vent.

I expected it to go up to about 130 but 150 was a surprise. Aparently, the system and Glycol is safe up to 170 - phew.

josip · 27-09-2013 10:34am

I think €4000 - around €1000 grant = net €3100
2011
m2 area - Whatever 18 tubes gives
Due South - 35 degrees pitch
Tubes
250l
No summer heat dump strategy

This year, I've been very happy. Yesterday I blipped the gas boiler to heat the water for the first time since 26th of March. 6 whole months of 100% free water.

The system has been troublesome before now however. Distance between panels and pump caused the pump to burn out, apparently due to conductive heat transfer one summer while we were on holidays. A longer pipe seems to have fixed that, but the pump twice since stopped workiing due to bubbles. We've been told this is more likely to happen because the pump is installed in the attic, not much below the panels.

quentingargan · 27-09-2013 10:55am

josip wrote: »

Distance between panels and pump caused the pump to burn out, apparently due to conductive heat transfer one summer while we were on holidays. A longer pipe seems to have fixed that, but the pump twice since stopped workiing due to bubbles. We've been told this is more likely to happen because the pump is installed in the attic, not much below the panels.

The pump is more likely to have suffered stagnation where the fluid in the panel and nearby turned to steam and moved to the expansion vessel. A heat dump would prevent this (unless there is a power cut) but you can also mitigate this by ensuring that stagnation doesn't go through the pump by the use of a high temperature non-return valve.

leo738 · 04-11-2013 7:23pm

This is a realtime feed of my system. The text at the bottom of the page is difficult to read but the details are there.

http://xively.com/feeds/61072

championc · 04-11-2013 11:28pm

And mine

https://xively.com/feeds/1928576781

John T Carroll · 08-11-2013 10:38pm

leo738 wrote: »

This is a realtime feed of my system. The text at the bottom of the page is difficult to read but the details are there.

http://xively.com/feeds/61072[/QUOTE]

Hi Leo,
I was looking through your interesting trends just now, I cant see in any period where SI (Solar Fluid temperature In) is higher than CB (Bottom of Cylinder temperature). Today, at 1200 hrs, SI was 42.0C (SO was 40.5) and CB was 46.6C. At 1300 hrs, SI was 44.7C (SO was 42.7) and CB was 53.1C.
Is there some factor being used in the SI and SO temperature indications? or maybe I'm just not interpreting the readings correctly. John

championc · 09-11-2013 1:14pm

Correct John

Looking at it right now, Leo's bottom of the cylinder is showing as 47 while Solar Fluid In is saying 43 and with both increasing, it doesn't make sense.

Qualitymark · 09-11-2013 4:43pm

How's the price of solar hot water systems moving these days, lads? Dearer or cheaper?

wonga77 · 13-11-2013 4:46pm

Are there grants available anymore for solar panels? I guessing not?

BryanF · 13-11-2013 4:57pm

wonga77 wrote: »

Are there grants available anymore for solar panels? I guessing not?

€800

gooseygander · 13-03-2014 9:41am

BryanF wrote: »

€800

I take that this grant is only available to renovations and that a new build does not qualify, is this the case ?

BryanF · 14-03-2014 2:40am

gooseygander wrote: »

I take that this grant is only available to renovations and that a new build does not qualify, is this the case ?

No new build grants. The Costs just keep rising..

championc · 14-03-2014 10:43am

BryanF wrote: »

No new build grants. The Costs just keep rising..

Maybe so but with the right system setup correctly, it will be paying fpr itself in about 10 years (based on current energy prices) or maybe less.

Follow my systems performance at

https://xively.com/users/championc/develop

JDoubleU · 28-03-2014 9:56am

I'm interested in solar thermal panels and the savings they provide. It would be great to hear from people (not companies) who have realised actual savings from solar thermal. I'm interested to know:

Your savings are in Euro.
If you have tube or flat plate
What direction they face.
Hot water or hot water & heating
What part of the country you live in.
What convinced you to buy that particular panel e.g. were you fed bs on savings etc. I have come across one company who shall remain nameless and have to say I'm not impressed with their BS.

I know savings will vary for each home depending on use but it would be great to see differences and get a real picture of what's out there.

Thanks in advance.

BryanF · 28-03-2014 5:02pm

JDoubleU wrote: »

I'm interested in solar thermal panels and the savings they provide. It would be great to hear from people (not companies) who have realised actual savings from solar thermal. I'm interested to know:

Your savings are in Euro.
If you have tube or flat plate
What direction they face.
Hot water or hot water & heating
What part of the country you live in.
What convinced you to buy that particular panel e.g. were you fed bs on savings etc. I have come across one company who shall remain nameless and have to say I'm not impressed with their BS.

I know savings will vary for each home depending on use but it would be great to see differences and get a real picture of what's out there.

Thanks in advance.

have read back through this thread

Are you all pleased with your solar panels for hot water heating

Comments