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

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


    It is important to get the correct sized collector for the size of the cylinder lots of tepid water will result.
    You say your system auto vents? Please explain.
    If there is an auto vent on the system you will lose all your fluid if it gets hot enough! A bypass cools the system without any drama, damage or refilling.


  • Registered Users Posts: 6,079 ✭✭✭championc


    freddyuk wrote: »
    It is important to get the correct sized collector for the size of the cylinder lots of tepid water will result.

    Indeed, I'm glad I never got 30 tubes with 300l store or you'd need nearly a week of sunshine I reckon to get over 60 deg - so long as to water is not heated by other means like an immersion or CH
    freddyuk wrote: »
    You say your system auto vents? Please explain.

    I understand that there is something special about the manifold / tube nozzles of the Kingspan tubes. There's no loss of fluid


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


    Rule of thumb is quoted as 7.5 litres per tube (1.8m x 58mm tubes) although some reckon 5 per tube is better as over sizing gives you a longer "season" so yours is not over sized.
    The essential thing is to have a way to cool the system down in the event of over heating which will happen in Summer and a basic bypass achieves this very effectively although it relies on an electronic valve to operate. Thermomax rely on an integrated spring valve device to retain steam in the system which is great providing it lasts 20 -30 years. In the event it fails the system will evacuate into the safety container and need recharging. I am not sure there is way of servicing this device so if it is required after some years of inactivity you just hope it works and is not corroded up. I can check my valve manually to ensure it works but for most customers this would not be an option unless they are keen DIY'rs. Keep it simple!!
    Let us know how the new system performs.


  • Closed Accounts Posts: 6,498 ✭✭✭Mothman


    freddyuk wrote: »
    It is important to get the correct sized collector for the size of the cylinder lots of tepid water will result.
    I don't subscribe to this thinking. Its important that supply meets the outgoings, usage plus loses. Once this happens, then generally the size of tank is not a major concern once the tank temperature is up. Though if it is poorly insulated then the losses are an issue and its harder to get through cloudy periods without backup and to keep tank temp up.

    I used to have 300l tank with my 6 sq m flat plates. My tank failed and I replaced it with a 500l store. Once I dealt with the tank loses (it was badly insulated) I am really thrilled with how its performing and it seems to be performing much better than my previous arrangement. The solar coil in this store is much larger than the previous tank and I guess I'm harvesting more energy. For past 4 weeks, I haven't needed any backup. Have had panels for 14 years and have always used backup in early April. I think my new store is part of the reason, the other is the sunny weather, well above average though not as sunny as last year or 2007.


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


    Yes - OK if the tank is stone cold and you get a half-decent day, you will end up with 500L of lukewarm water that day, but sooner or later the heat will accumulate, provided you aren't losing it through poor insulation.

    By the way, there is a myriad of "solar" cylinders that have two coils, but the bottom one for solar is not a high surface area coil. I have seen 300L ones with coils that had a surface area less than 0.7M2. Ideally the coil should have a surface area of at least 0.25 sqM per sqM of solar panel.


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  • Registered Users Posts: 6,079 ✭✭✭championc


    freddyuk wrote: »
    Let us know how the new system performs.

    There was a setting missing on the controller which I have had clarified this morning with Steca. The threshold for the upper section was set to 60 deg C but over the weekend, it kept dumping the heat into the bottom section even though the top was at 51 deg C. It needs a "Quick Charge" function to be turned ON.

    So hopefully, by the weekend, I can look forward to +50 deg C hot water in the top section for a large portion of the year and the same in the bottom section full during the summer months.


  • Registered Users Posts: 6,079 ✭✭✭championc


    I had a call with the Steca guy in Germany today who basically said that the system balances between top loading and boosting the whole system in the cleverest way, getting the best use from the energy being harvested (at least I think that's what he was getting at)

    I have reviewed my data from today and the bottom seems to be getting topped up as it goes along, staying within about 8 deg of the top temperature which is not quite what I had hoped for.

    I'll reserve judgement until I have lots more data but it certainly does not seem possible, using the controller, to load the top up to a certain level and then go to the bottom.


  • Registered Users Posts: 16 johnfoyvision


    could you pm the company me too please.....


  • Registered Users Posts: 6,079 ✭✭✭championc


    My Data is now online 24 x 7 x 365

    See https://cosm.com/feeds/71436


  • Registered Users Posts: 315 ✭✭RTT


    championc wrote: »
    My Data is now online 24 x 7 x 365

    See https://cosm.com/feeds/71436

    Impressive! Are they the temperatures you are achieving at the moment without any other source of heat other than solar?


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  • Registered Users Posts: 6,079 ✭✭✭championc


    RTT wrote: »
    Impressive! Are they the temperatures you are achieving at the moment without any other source of heat other than solar?

    Absolutely, no other source

    I have a Combi boiler if the solar comes up short during the year.


  • Posts: 21,179 ✭✭✭✭ [Deleted User]


    It costs me 30 Euro's or so to heat the water with the immersion over the 5 months a year we don't need the heat.

    In winter the heating heats the water costing hardly anything extra.

    That's a very very very long time to pay back a 3k + solar thermal system ?

    I would have thought Solar P.V would have been a better option for people because when your solar is generating it can continually export to the grid when you don't need it making you money. Or you buy it back at half the price during the night.


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


    Quick calculation says that is only using immersion for half an hour once a day for 150 days? (excluding standing charge and VAT)
    If you use hot water for baths/showers, washing up/dishwasher, washing machine it is not a huge amount of hot water. If you have a cold fill washing machine then you not using that but if you have hot fill machines the solar goes straight in so can be a benefit.
    My temp in West Cork now are 50c on the roof and 45c in the buffer. It is a nasty day for solar! 39 tubes into 200 litre buffer. It may have dumped some heat into the DHW cylinder already - but unlikely today.


  • Posts: 21,179 ✭✭✭✭ [Deleted User]


    freddyuk wrote: »
    Quick calculation says that is only using immersion for half an hour once a day for 150 days? (excluding standing charge and VAT)
    If you use hot water for baths/showers, washing up/dishwasher, washing machine it is not a huge amount of hot water. If you have a cold fill washing machine then you not using that but if you have hot fill machines the solar goes straight in so can be a benefit.
    My temp in West Cork now are 50c on the roof and 45c in the buffer. It is a nasty day for solar! 39 tubes into 200 litre buffer. It may have dumped some heat into the DHW cylinder already - but unlikely today.

    Including vat excluding standing charge which I and solar Thermal users have to pay anyway.

    If you use loads of hot water maybe I can see a few year payback, but not for us as we conserve and we waste as little as possible.

    Our yearly electric bill is around 550 per year in total. including a cold fill washing machine and to be honest you would want your washing machine close to the hot water cylinder to benefit as it would be nearly full by the time it fills up, unless you run the tap first.

    We don't have a dish washer and a kettle of water does the job nicely.

    I'd be more willing to install a night saver meter if I used a lot of leccy over a solar thermal.

    If I could have solar thermal for my heating it might be more worth my while, but I would think that would have to be pretty large and expensive and then in winter daylight hours are short.


  • Registered Users Posts: 235 ✭✭steifanc


    sinnerboy wrote: »
    I'll sticky this awhile and add

    Please indicate

    cost self installed 3k
    year of installation last week
    m2 area 80,tubes
    orientation south
    flat plate or tubes tubes
    cylinder size 300lt
    summer heat dump strategy , ability to transfer from the 300l tank to a 500lt buffer and after that into the floor , when the 300l tank hits 70 degrees it dumps ontill it reaches 60 degrees
    So far happy , plenty of hot water this week , tanks sits around 55/60 all this week , hopefully it performs in the winter

    Reminder - no trade / company names please

    .
    .


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


    championc wrote: »
    My Data is now online 24 x 7 x 365

    See https://cosm.com/feeds/71436

    Well today I had /have 72c on the roof and buffer is 67 top and 66 bottom in 200 litres which seems pretty good compared to your expensive thermomax against my cheapo Chinese kit. :D


  • Posts: 21,179 ✭✭✭✭ [Deleted User]


    freddyuk wrote: »
    Well today I had /have 72c on the roof and buffer is 67 top and 66 bottom in 200 litres which seems pretty good compared to your expensive thermomax against my cheapo Chinese kit. :D

    Can you provide a link to the kit you got ?


  • Registered Users Posts: 6,079 ✭✭✭championc


    freddyuk wrote: »
    Well today I had /have 72c on the roof and buffer is 67 top and 66 bottom in 200 litres which seems pretty good compared to your expensive thermomax against my cheapo Chinese kit. :D

    There are potentially so many variables here but as a matter of interest,

    a. how many tubes do you have ?
    b. how many deg of an increase did you get today ?

    The great thing about data is that you can visibly see if something is not working correctly.


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


    Of course there are and I am just tweaking you a bit! But anyway I did post my reading yesterday above. There is no log burner going so no additional heat into the buffer it is all Thermal at the moment.
    42 tubes are 58mm


  • Registered Users Posts: 6,079 ✭✭✭championc


    So 40 up to 66 - not bad at all. Decent return on your investment there.


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


    I am at 70c today top and bottom.


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


    30 Chinese tubes into 200 litre tank was at 65* yesterday having started the day at 31* it also heat dumped twice into central heating circuit yesterday as i dont let the water go above 65*(hard water)


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


    Nice one! Up the Chinese!!:D


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


    Would anyone know what the *wholesale* price of solar panels is? I mean, if the Government bought half a million of them wholesale, and employed all the workless builders and plumbers and electricians to put them in on people's rooves (thus slashing Ireland's carbon footprint), with people paying the wholesale price plus the installers' wages, how much would the panels cost?


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


    Would anyone know what the *wholesale* price of solar panels is? I mean, if the Government bought half a million of them wholesale, and employed all the workless builders and plumbers and electricians to put them in on people's rooves (thus slashing Ireland's carbon footprint), with people paying the wholesale price plus the installers' wages, how much would the panels cost?

    Not an awful lot less I'm afraid. There are also cylinders, pipes, pump stations etc. Most suppliers are working on lower margins than most hardware these days.


  • Registered Users Posts: 4,939 ✭✭✭goat2


    i do not use the immersion, in fact i have disconnected it from the mains, as it is not needed, could one get a spiral going from the solar panel to the tank taking out the immersion element and using the intrance of the element to put in a spiral from the panels, and in doing so save the price of tank and labour time


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


    goat2 wrote: »
    i do not use the immersion, in fact i have disconnected it from the mains, as it is not needed, could one get a spiral going from the solar panel to the tank taking out the immersion element and using the intrance of the element to put in a spiral from the panels, and in doing so save the price of tank and labour time

    There is a unit that can replace the immersion (and which has a replacement, smaller immersion) for about €250. PM Sent. Or you could get a unit made up by someone with oxy-actetylene.

    However, there are other issues to watch out for. You can only use this with quite a small panel, and usually the existing cylinder is quite poorly insulated. But if that suits your needs for a modest hot water supply it is a convenient solution. You will need to insulate other pipes coming from the cylinder to ensure there is no heat loss into the heating system for example.


  • Registered Users Posts: 45 Roundtd181


    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!!


  • Registered Users Posts: 6,079 ✭✭✭championc


    I've never heard Chinese and Kingspan and Poor Quality ever being mentioned in the same sentence.

    As for Tubes vs Flat Plate - do some research but my understanding is that Flat Plate deliver more heat under a cloudless sky but significantly less under broken sunshine. I think they also rely on the Sun to be alot more overhead so would not be too good with winter sunshine. With tubes, if you have a cloudless sky, you'll have no shortage anyway of hot water so you really want to maximize gains in Spring and Autumn

    Hope this helps


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  • Registered Users Posts: 45 Roundtd181


    championc wrote: »
    I've never heard Chinese and Kingspan and Poor Quality ever being mentioned in the same sentence.

    As for Tubes vs Flat Plate - do some research but my understanding is that Flat Plate deliver more heat under a cloudless sky but significantly less under broken sunshine. I think they also rely on the Sun to be alot more overhead so would not be too good with winter sunshine. With tubes, if you have a cloudless sky, you'll have no shortage anyway of hot water so you really want to maximize gains in Spring and Autumn

    Hope this helps

    Sorry shouldn't be slating Kingspan like that. One particular renewable guy near to where i live is selling and fitting solarfocus panels and he insists these are a far superior panel to the Kingspan panels. I would be interested to find out some thoughts from someone who knew both systems as he could be saying this as a selling tool.

    Taking into account the pro's and con's of flat plate and tubes i will go going with the flat plate as the house is new build and i am doing this purely for aesthetics.


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