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Solar + Battery Storage on New Build Opinions

  • 30-06-2019 11:10pm
    #1
    Registered Users Posts: 1,365 ✭✭✭ blobert


    Hi Guys,

    I've had a largely negative experience with solar so far. I bought a newly built house with solar panels heating water about 4-5 years ago. I suspect is was a cheap system for compliance and the panels faced east on a sloped roof so don't get a lot of the sun. We had issues with the system from about 1 year in, I suspect the plumber that installed it was not an expert and the pressure kept dropping. He charged us several hundred euro to repressurise the system so the next time it broke we got someone else who also seemed to think it was leaking/poorly installed. In total I reckon we've spent far more on "maintenance" than it's generated in electricity.

    We're planning to move and build a new house in the next few months, I'm hoping to build a very efficient/airtight new house probably prefabricated by a German company. It's going to be a pretty big (circa 400m2) house and most likely a bungalow.

    While the house will probably be heated with a heat pump I suspect that alone might may not be sufficient for it to meet renewable energy requirements so we may have to have some sort of solar setup.

    The house will be facing perfectly south, with no shading and probably have a flat roof so I'm guessing with holders for panels we could pretty much have the perfect angle for solar.

    While I'm a bit reluctant to go the solar for water heating route again I was thinking of possibly going for quite a lot of panels and a battery storage system, ie going all out on it. I kind of like the idea of being able to produce much of our own electricity.

    Though from reading up on it here I get the feeling there is no rational economic basis to do this, ie battery storage is expensive and the payback time is likely to be 15+ years?

    Just one thing I've not seen discussed too much. If I went the battery storage route would I be able to charge the battery using night saver rates. Ie if the battery storage was sufficient to cover all our use day to day could I either get all our power from solar (in the summer months) or a combo of solar and night saver rates in the winter, ie basically never use day electricity rates. I'm guessing this might help a bit with the payback time of the system?

    Any advice on this would be much appreciated.


Comments

  • Registered Users Posts: 2,442 ✭✭✭ wexfordman2


    Thats what my system is doing, it can be programmed to program from ac at specific times, so one my solar production dips, I will turn on ac charging for night rate times, together me cheap rate power for the day (although the battery at 5kwh wont last a full day unless its topped up with solar),.

    Still, will be able to get some good savings from that during the winter.


  • Registered Users Posts: 585 ✭✭✭ peaceboi


    Thats what my system is doing, it can be programmed to program from ac at specific times, so one my solar production dips, I will turn on ac charging for night rate times, together me cheap rate power for the day (although the battery at 5kwh wont last a full day unless its topped up with solar),.

    Still, will be able to get some good savings from that during the winter.

    Sounds clever idea. Which company you used for your installation if you don't mind sharing? I got a quote of 16k eur from Tesla for 2 power wall plus solar panels.


  • Registered Users Posts: 2,442 ✭✭✭ wexfordman2


    I would guess that the Tesla battery system was white a large configuration at that.

    PM you the installer, but suffice to say, at the price you quoted above, you would get a maxed out solar Pv system, with 5kwh battery and an eddi hot water diverter while still having a large chunk of change left (ie several thousand left over).


  • Closed Accounts Posts: 3,364 ✭✭✭ rolion


    As we are on a public forum and you asked a question...

    I think that you are putting all the egs in a single basket.
    Also, that are following with one solution that everyone feels is doing fine because everyone else is doing it... cause thats all is at th epeak market today for the homes built in cities and big estates.

    So, without mentioning any budget at all, by you and by me, ok !?
    No matter whats the cost "TODAY" it will be targetted to be zero "TOMMOROW".

    You need in the new house, built by Germans for Germans on the Continent:
    electricity,220V and possible 12V
    fresh water for drinking and for domestic,probable for garden
    hot water for washing
    heating for rooms
    ventilation for your health and for your house well being

    I will go with:

    ground based heat pump,as deep as i can based on the location and cost.Get three pipes inside,one for the water,one for the heat pump and one for the air for heat recovery. You still need to drill one single hole,charged accordingly . Do all the "magic" in a single technical room and use it as a distribution room everywhere in the house.

    heat recovery ventilation,round plastic 90mm tubes, centralised solution, 2 manifolds, 550mc type unit.Get the input air for HRV from the pipe coming from the deeper grunds where a constant 15 degrees present all year along. Some manufacturers have a nice "magic" computerised solution.You can use that for heating or cooling the house as well,if you know how to use it "smart" way combined with the heat pump input and fit vertical pipes inside the walls.

    underfloor heating every where acrous the floors,centralised and controlled at manifold level, zoned by room type and / or by the surface size constraints,use computerised "magic" controls for sensors and for timers.

    solar tubes ,i know some of the posters here completely mad and hates them as the posters cannot comprehend tubes performance ,understand complexity and visualise usage of the tubes.I can confirm i was one of them until i got the tubes on my roof.Now,after 3 years of usage,they are a blessing and outperform pv panels any day of the year. Fit maybe 40-60 panels,max that you can afford and a good specs. Get a 1000L puffer and a 300L hot cylinder.Do "magic" in the tech room and you can have:
    -permanent hot water at sink
    -permanenet hot water at bath
    -hot water for underfloor heating at mild start-up mixed temperatures as you will have heat pump as well

    PV solar panels for all the electricity needs,maxim 6kw panels for out grid but you can have more Kw if you go three phases and you can have a "magic" configuration that limits the excess to Mr Grid, even with the FIT maybe present by then. Divert all the excess to the puffer and hot cylinder,with first output to the cylinder and second output to puffer' immersions.Then, FIT if needed so.

    Of course,"magic" means lots of home work and reading literature and documentation and "how-to" don't do things,as presented by other owners. Needs to do "thinking out of the box" and installlers to run it your way, not the most profit efficient for them.

    Regarding manufacturer,if you check the market on the continent,there are already pre-made solutions described above. Or,pick something from one single supplier only, dont mix more than one supplier in a single provided / installed / used solution as that will create issues and they will love pointing fingers to each another,even blaiming for a single valve that does not open as is fitted by other techie!
    Major "magic" here is to get something that can talk one to another ,maybe using BMS software solution so that all "magic" could happen in the technical room while you, as a happy owner, just check status and respond to alerts and / or changes on your smart device(s).
    Same,after sale ssupport is critical. If your one of the solutions installed above fails, you still have something to fall back and to use it,in any "recovery mode" limited usage scenarious without causing a total loss of service or giving out from your wife... we call in the office a "CV review generating events" .

    Thast all for a short 5 minute crash planning of your new home,please feel free to change or add...now let me check my Lotto tickets ... ;)

    In my culture, we say don't curse the man something bad...just wish him to build a house in his lifetime and that will be enough blessing!
    Good luck and God Bless you in the wonderful endeavour !


  • Registered Users Posts: 7,265 ✭✭✭ threeball


    blobert wrote: »
    Hi Guys,

    I've had a largely negative experience with solar so far. I bought a newly built house with solar panels heating water about 4-5 years ago. I suspect is was a cheap system for compliance and the panels faced east on a sloped roof so don't get a lot of the sun. We had issues with the system from about 1 year in, I suspect the plumber that installed it was not an expert and the pressure kept dropping. He charged us several hundred euro to repressurise the system so the next time it broke we got someone else who also seemed to think it was leaking/poorly installed. In total I reckon we've spent far more on "maintenance" than it's generated in electricity.

    We're planning to move and build a new house in the next few months, I'm hoping to build a very efficient/airtight new house probably prefabricated by a German company. It's going to be a pretty big (circa 400m2) house and most likely a bungalow.

    While the house will probably be heated with a heat pump I suspect that alone might may not be sufficient for it to meet renewable energy requirements so we may have to have some sort of solar setup.

    The house will be facing perfectly south, with no shading and probably have a flat roof so I'm guessing with holders for panels we could pretty much have the perfect angle for solar.

    While I'm a bit reluctant to go the solar for water heating route again I was thinking of possibly going for quite a lot of panels and a battery storage system, ie going all out on it. I kind of like the idea of being able to produce much of our own electricity.

    Though from reading up on it here I get the feeling there is no rational economic basis to do this, ie battery storage is expensive and the payback time is likely to be 15+ years?

    Just one thing I've not seen discussed too much. If I went the battery storage route would I be able to charge the battery using night saver rates. Ie if the battery storage was sufficient to cover all our use day to day could I either get all our power from solar (in the summer months) or a combo of solar and night saver rates in the winter, ie basically never use day electricity rates. I'm guessing this might help a bit with the payback time of the system?

    Any advice on this would be much appreciated.

    We used a gshp which is PV ready. It can be set up to recognise when power is going back on to the grid and it will utilise it to produce additional hot water or increase the floor temp.

    In the summer if you use the passive cooling function your pv would run that too. Couple that with a modest battery and you would end up with seriously low electricity bills. From my research solar thermal was never a great success from a payback perspective but PV is much better and much more reliable.


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  • Closed Accounts Posts: 3,364 ✭✭✭ rolion


    threeball wrote: »
    We used a gshp which is PV ready. It can be set up to recognise when power is going back on to the grid and it will utilise it to produce additional hot water or increase the floor temp.

    In the summer if you use the passive cooling function your pv would run that too. Couple that with a modest battery and you would end up with seriously low electricity bills. From my research solar thermal was never a great success from a payback perspective but PV is much better and much more reliable.

    Hi,

    I am not going to start again a war between PV panels and solar tubes...
    From my real usage for the past 3 (three) years of both systems, i can give feedback based on graphs and numbers.
    I can say here that people are afraid of solar tubes, cant visualise the functionality and running of them and throw the negativism about the whole solution. "Yes, PV panels are much better, i can see the cables attached and the panels on the roof and voila...they are magnifique" !

    Also, more people don't realise that there is a generous grant for both systems ,as well.
    To get a 300l cylinder warmed up 9 out of 12 months, with solar tubes, cost you installed and with grant around €2,500 on the roof.
    To get same results, you will need a minimum guaranteed 3KWh installed power to give you a constant immersion wattage to warm up the water over couple of hours. So, that will be maybe 6KW panels !? Priced at over €5k maybe !?
    AND, there are days when solar PVs are warming the inverter while solar tubes keeps the pump running at maximum speed assuring a much better heat transfer through the solar coil than a "sticky" immersion stick .

    Yesterday, my solar tubes have raised the temperatures top to bottom in the 300l cylinder to over 70 degrees, by 2pm and with no one using the water.
    By same time, my PV panels have produced maybe 13KWh,with an overall across day of 22KWh … AND gave free to grid 4Kwh after hot tank sensor were on.
    I confirm that my both systems are not fully optimised due to location compromised.


    In relation to heat pumps and PV module, i did my home work years ago and they demanded a minimum running power from the grid with the excess from PVs used to add extra capacity. I will not be happy to have the Heat pump running of the PV solar panels at all... but a heat pump with solar tubes and some "magic" in the technical room makes a much more and better overall return of investment and , to quote you, payback, reliable and comfort.

    Regarding battery, i have to be crazy mad blind deaf to invest in a battery these days to run anything than the lights and life critical equipment in case of power failure. How many richest of the richer have battery installed in their homes... I will be curious to see how many batteries systems are installed in Ireland AND I bet you those that got the battery installed...got it installed so that the grant covered some of the cost and installer made a better profit on installation. Let's talk about same batteries in one / two years when winter-summer-winter cycled the life SOCs of those lithium cells...

    Plan your systems for minimum output to outside of your house boundary and maximum efficiency for internal usage... I prefer to run a pump all day watering the garden from a well than to give it to grid for free...

    Good luck...


  • Registered Users Posts: 7,265 ✭✭✭ threeball


    rolion wrote: »
    Hi,

    I am not going to start again a war between PV panels and solar tubes...
    From my real usage for the past 3 (three) years of both systems, i can give feedback based on graphs and numbers.
    I can say here that people are afraid of solar tubes, cant visualise the functionality and running of them and throw the negativism about the whole solution. "Yes, PV panels are much better, i can see the cables attached and the panels on the roof and voila...they are magnifique" !

    Also, more people don't realise that there is a generous grant for both systems ,as well.
    To get a 300l cylinder warmed up 9 out of 12 months, with solar tubes, cost you installed and with grant around €2,500 on the roof.
    To get same results, you will need a minimum guaranteed 3KWh installed power to give you a constant immersion wattage to warm up the water over couple of hours. So, that will be maybe 6KW panels !? Priced at over €5k maybe !?
    AND, there are days when solar PVs are warming the inverter while solar tubes keeps the pump running at maximum speed assuring a much better heat transfer through the solar coil than a "sticky" immersion stick .

    Yesterday, my solar tubes have raised the temperatures top to bottom in the 300l cylinder to over 70 degrees, by 2pm and with no one using the water.
    By same time, my PV panels have produced maybe 13KWh,with an overall across day of 22KWh … AND gave free to grid 4Kwh after hot tank sensor were on.
    I confirm that my both systems are not fully optimised due to location compromised.


    In relation to heat pumps and PV module, i did my home work years ago and they demanded a minimum running power from the grid with the excess from PVs used to add extra capacity. I will not be happy to have the Heat pump running of the PV solar panels at all... but a heat pump with solar tubes and some "magic" in the technical room makes a much more and better overall return of investment and , to quote you, payback, reliable and comfort.

    Regarding battery, i have to be crazy mad blind deaf to invest in a battery these days to run anything than the lights and life critical equipment in case of power failure. How many richest of the richer have battery installed in their homes... I will be curious to see how many batteries systems are installed in Ireland AND I bet you those that got the battery installed...got it installed so that the grant covered some of the cost and installer made a better profit on installation. Let's talk about same batteries in one / two years when winter-summer-winter cycled the life SOCs of those lithium cells...

    Plan your systems for minimum output to outside of your house boundary and maximum efficiency for internal usage... I prefer to run a pump all day watering the garden from a well than to give it to grid for free...

    Good luck...

    I think your research on pv and heat pumps is out of date. The one I bought can sense how much energy is going back on to the grid then modulate the compressor to just below this level to allow for drop offs due to cloud cover etc. Getting 5 to 1 on free electricity is as good a deal as you'll get anywhere and far far better than solar thermal tubes.


  • Closed Accounts Posts: 3,364 ✭✭✭ rolion


    threeball wrote: »
    I think your research on pv and heat pumps is out of date. The one I bought can sense how much energy is going back on to the grid then modulate the compressor to just below this level to allow for drop offs due to cloud cover etc. Getting 5 to 1 on free electricity is as good a deal as you'll get anywhere and far far better than solar thermal tubes.

    Great, thanks for sharing and happy to see tech has evolved.
    May I ask what brand model you have please !?

    I was looking at Panasonic then I started falling in love with Viessman and to Nibe as they had all built-in units … but few guys around here knew to speak their language...
    Here, if is not "Made in England" is not good supported.


  • Registered Users Posts: 7,265 ✭✭✭ threeball


    rolion wrote: »
    Great, thanks for sharing and happy to see tech has evolved.
    May I ask what brand model you have please !?

    I was looking at Panasonic then I started falling in love with Viessman and to Nibe as they had all built-in units … but few guys around here knew to speak their language...
    Here, if is not "Made in England" is not good supported.

    We went with Ovum, an Austrian manufacturer. The Irish supplier was not far from us either which helps.


  • Registered Users Posts: 1,365 ✭✭✭ blobert


    Thanks very much for the replies guys I really appreciate them.

    The ground based heat pump combined with mechanical heat recovery system sounds interesting.

    Particularly as it might offer an option for cooling the house in summer without needing air conditioning (which I hate)

    Our current house A Rated, has lots of windows and suffers from getting incredibly hot in the summer (it was 40+ degrees when we came back from a holiday!) and the new house will probably have a ton of south facing glass so I'm keen to find a way to be able to keep the house warm in the winter (not hard) but also relatively cool in the summer without needing air conditioning.

    If we went the ground based heat pump route that might cover us in terms of Part L so we could leave the solar requirement altogether or wait a bit longer till the battery storage prices come down to levels to make it more attractive.


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  • Closed Accounts Posts: 3,364 ✭✭✭ rolion


    If you design your house so that it can take advantages of the Sun position, the angle of the roof and the windows. Same, combined with the floor type, it can be used as a heat storage too...
    There is a clips on YT that explains in more details how to do it, i think is "earth homes", i will attach it later on.

    484224.jpg

    484225.jpg

    Also,forget about the batteries "today", they are not a good solution unless you are going off the grid.

    The reverse of the heating is the cooling !
    Cooling a house can be down with ground heat pump, heat recovery ventilation and ..underfloor heating ! ;) All is in the "magic" from the technical room.


  • Registered Users Posts: 7,265 ✭✭✭ threeball


    blobert wrote: »
    Thanks very much for the replies guys I really appreciate them.

    The ground based heat pump combined with mechanical heat recovery system sounds interesting.

    Particularly as it might offer an option for cooling the house in summer without needing air conditioning (which I hate)

    Our current house A Rated, has lots of windows and suffers from getting incredibly hot in the summer (it was 40+ degrees when we came back from a holiday!) and the new house will probably have a ton of south facing glass so I'm keen to find a way to be able to keep the house warm in the winter (not hard) but also relatively cool in the summer without needing air conditioning.

    If we went the ground based heat pump route that might cover us in terms of Part L so we could leave the solar requirement altogether or wait a bit longer till the battery storage prices come down to levels to make it more attractive.

    Ground source will almost certainly get you passed without any other system. You can leave the panels til later, just make sure to run the cables etc. That's what I did. Way more expensive to do it after. Put out the cable for a car charger too.


  • Registered Users Posts: 10,927 ✭✭✭✭ Calahonda52


    400 sqm flat roof: check that you can get house insurance.
    400 sqm flat roof, check out decrement delay
    You need to take the new part L and F into the mix.
    You will need solar shading on the south

    Solar Thermal vs Solar PV
    The fundamental issue with Thermal is that it only gives you hot water.
    The concept of "free" hot water from Thermal is driving bad behaviour on water usage, both cold and hot.
    PV gives you better options with a higher grade of energy.
    The setup is much less complex, with little maintenance.

    The best example I have seen with Thermal is a guy who buried a series of concrete tanks in his front garden and fed the solar thermal into the tanks so it used all the heat the sun could offer: he had 6 by 30 tubes :)
    He then used a GSHP setup, with the coils in the tanks....


  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 58,874 CMod ✭✭✭✭ unkel


    Brother in law uses 90 tubes to heat his indoor swimming pool. Pretty efficient use of solar thermal too.

    "Wind is Ireland's oil" - An Taoiseach, 25/05/2022



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