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

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  • Closed Accounts Posts: 757 ✭✭✭John T Carroll


    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.


  • Registered Users Posts: 1,391 ✭✭✭dathi


    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


  • Closed Accounts Posts: 757 ✭✭✭John T Carroll


    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


  • Registered Users Posts: 6,084 ✭✭✭championc


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


  • Closed Accounts Posts: 757 ✭✭✭John T Carroll


    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.


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  • Closed Accounts Posts: 757 ✭✭✭John T Carroll


    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.


  • Registered Users Posts: 45 Roundtd181


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


  • Closed Accounts Posts: 757 ✭✭✭John T Carroll


    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.


  • Registered Users Posts: 1,110 ✭✭✭freddyuk


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


  • Closed Accounts Posts: 6,824 ✭✭✭Qualitymark


    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*!


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  • Registered Users Posts: 1,282 ✭✭✭sas


    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.


  • Closed Accounts Posts: 6,824 ✭✭✭Qualitymark


    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?


  • Registered Users Posts: 1,282 ✭✭✭sas


    UFH?

    Under floor heating


  • Closed Accounts Posts: 6,824 ✭✭✭Qualitymark


    sas wrote: »
    Under floor heating

    Envyyyyyyyyy!!!


  • Registered Users Posts: 1,282 ✭✭✭sas


    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.


  • Registered Users Posts: 1,391 ✭✭✭dathi


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


  • Closed Accounts Posts: 6,824 ✭✭✭Qualitymark


    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?


  • Registered Users Posts: 1,282 ✭✭✭sas


    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.


  • Registered Users Posts: 1,391 ✭✭✭dathi


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


  • Registered Users Posts: 1,282 ✭✭✭sas


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

    Yeah, there you go.


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  • Closed Accounts Posts: 6,824 ✭✭✭Qualitymark


    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?


  • Registered Users Posts: 1,282 ✭✭✭sas


    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.


  • Registered Users Posts: 1,110 ✭✭✭freddyuk


    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


  • Registered Users Posts: 308 ✭✭jakko86


    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??


  • Closed Accounts Posts: 8 jdrysdale


    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.


  • Closed Accounts Posts: 6,824 ✭✭✭Qualitymark


    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?


  • Closed Accounts Posts: 8 jdrysdale



    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.


  • Registered Users Posts: 1,627 ✭✭✭quentingargan


    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.


  • Registered Users Posts: 3 lainatro


    any comments on thermomax??


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  • Registered Users Posts: 6,084 ✭✭✭championc


    lainatro wrote: »
    any comments on thermomax??

    Read through the thread


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