Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie

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

Options
1356714

Comments

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


    to continue

    A pipe enters your cylinder and goes around and around in the shape of a spring and then exits the cylinder. If the liquid is hotter than the water inside the cylinder, and is travelling slowly enough, it will transfer the heat from the coil into the cylinder water.

    images?q=tbn:ANd9GcRXaxDqTi4pS-E-rZ_kdQyMggsJBAkODV762c7FYAFSe3JcHw67DQ

    I personally am trying to see if it's worth my while for this transfer to happen in the opposite direction - transferring surplus heat from the cylinder back into the radiator circuit. It's a larger scale version of heat dumping.

    Anybody done this ?


    C


  • Registered Users Posts: 1,020 ✭✭✭Coles


    championc wrote: »
    I personally am trying to see if it's worth my while for this transfer to happen in the opposite direction - transferring surplus heat from the cylinder back into the radiator circuit. It's a larger scale version of heat dumping.

    Anybody done this ?


    C
    One interesting way to deal with surplus summer/autumn heat would be to incorporate a seasonal thermal store, - basically an extremely well insulated and large thermal mass. Might be difficult to incorporate into an existing house, but if might work in some scenarios.

    Wikipedia link to 'Seasonal Thermal Stores'.


  • Registered Users Posts: 423 ✭✭ccsolar


    Coles wrote: »
    championc wrote: »
    I personally am trying to see if it's worth my while for this transfer to happen in the opposite direction - transferring surplus heat from the cylinder back into the radiator circuit. It's a larger scale version of heat dumping.

    Anybody done this ?


    C
    Hi Champion
    We fit this type regularly in existing houses when there is a circulating pump near the hot water cylinder.
    It works well in summer as a heat dump but you will need a special controller or a pipe stat to set it up.
    Cc


  • Registered Users Posts: 1,700 ✭✭✭firemansam4


    championc wrote: »
    I personally am trying to see if it's worth my while for this transfer to happen in the opposite direction - transferring surplus heat from the cylinder back into the radiator circuit. It's a larger scale version of heat dumping.

    Anybody done this ?


    C

    In one system we were working on in the past I seen this happen by accident,
    What happened was in mid summer the cylinder got to very high temperatures of around 90 degrees c, The solid fuel stat was probably located a little too close to the cylinder and the temperature traveled down the solid fuel pipe off the solid fuel coil in the cylinder, it then knocked off the solid fuel pump and took a good bit of heat out of the cylinder to the radiators, but they would of went just luke warm and reduced the temperature of the cylinder from 90 c to about 55 c. It was a 300 l cylinder.

    but even without this if lets say this time of year you start putting on your heating and it has been a very sunny day outside, it is possible that your cylinder can be up at 80 or 90 degrees and the heating system could be running at 70 degrees so what happens is opposite transfer through the heating coil only a small bit albeit


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


    but even without this if lets say this time of year you start putting on your heating and it has been a very sunny day outside, it is possible that your cylinder can be up at 80 or 90 degrees and the heating system could be running at 70 degrees so what happens is opposite transfer through the heating coil only a small bit albeit

    I know this is a very vague question but hopefully someone can give me a less vague answer - If my store was at 75 and I turned on my rads pump (without the boiler) to allow for the store heat to transfer into the rads circuit, how long would you expect before I would begin to feel some heat from rads - 10 mins, an hour ........

    My thought would be to put a temperature controlled valve in place to basically allow the store to dump heat once the store temp was over 55 deg.

    Or maybe a simpler proposition, In a typical setup that has a rad as a heat dump, how quickly does a rad like this heat up and how long would a store at 75 take to be reduced down to 55 (basically allowing for the use of the store hot water that night or the next morning)


    C


  • Advertisement
  • Registered Users Posts: 1,700 ✭✭✭firemansam4


    championc wrote: »
    I know this is a very vague question but hopefully someone can give me a less vague answer - If my store was at 75 and I turned on my rads pump (without the boiler) to allow for the store heat to transfer into the rads circuit, how long would you expect before I would begin to feel some heat from rads - 10 mins, an hour ........

    My thought would be to put a temperature controlled valve in place to basically allow the store to dump heat once the store temp was over 55 deg.

    Or maybe a simpler proposition, In a typical setup that has a rad as a heat dump, how quickly does a rad like this heat up and how long would a store at 75 take to be reduced down to 55 (basically allowing for the use of the store hot water that night or the next morning)


    C

    I think in my last example i give which would have been something like what you want to do, it took about 10 to 20 minutes to start feeling the radiators heat, but like i said it was only to a slight luke warm of all the rads, if you were doing this to try heat the house I personally cant see it really doing much, it might be of more use as something that would kick in maybe 20 minutes before the heating comes on, to save a little on the heating fuel costs.
    But this is just an opinion - I could very well be wrong, i've never actually tried fitting a solar system to heat radiators, just to heat DHW


  • Registered Users Posts: 1,382 ✭✭✭gjc


    Excuse me I am thinking of getting solar panels to heat water only looking at 300l tank evacuated tube system...trying to sift through info .....can I ask what temperature is the water heating up to at this time of year?? Also what is the best way of comparing different products. Any help would be grateful.


  • Registered Users Posts: 4,748 ✭✭✭Do-more


    gjc wrote: »
    Also what is the best way of comparing different products.

    Comparing different solar panels is not a particularly easy task (in my experience at least :o).

    Decent panels should be certified and appear in the Solar Keymark database. It's easiest if you are comparing two panels which are both certified by the same certification body such as DIN the German certification body.

    You will need get the licence number for the panels you are looking for from your supplier, hopefully it will be on their literature or website and then get the test data sheet for that panel from the data base. The licence number will look something like this: 011-7S206 R

    You should then be able to compare the performance of the panels under test conditions for a location in Germany.

    Whilst the output you get in Ireland won't be the same as for the test location it does at least give you a chance to make a comparison between panels and relating that back to the price you are being quoted for installation you can see which is giving you the most bang for buck.

    It's also helpful to look at the stagnation temperature of the panels which is given on the test data sheets the higher the temp. the better.

    The whole process is not very user friendly and can be pretty baffling but it's the best I can offer you.

    invest4deepvalue.com



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


    For 300l tank I would suggest 50 tubes.

    I have 30 and 180l and on a full sunny day at present, I can raise the whole store by about 15 deg C. The highest I've been during November is about 52 deg C (good sunshine 04 - 07 Nov) with the lowest at 15 deg C. I have a combi boiler so I can send pre-heated water to the boiler to then raise it to the required 45 / 46 deg C to deliver to the taps so I am never wasting any heat really - I only heat what I use.

    Here's a pic of my data from 22 Nov 2011
    22112011.jpg


  • Registered Users Posts: 423 ✭✭ccsolar


    gjc wrote: »
    Excuse me I am thinking of getting solar panels to heat water only looking at 300l tank evacuated tube system...trying to sift through info .....can I ask what temperature is the water heating up to at this time of year?? Also what is the best way of comparing different products. Any help would be grateful.
    PM sent
    Cc


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


    BTW, for anyone who is wondering, Kingspan re-badge Steca controllers


  • Registered Users Posts: 182 ✭✭saibhne


    gjc wrote: »
    Excuse me I am thinking of getting solar panels to heat water only looking at 300l tank evacuated tube system...trying to sift through info .....can I ask what temperature is the water heating up to at this time of year?? Also what is the best way of comparing different products. Any help would be grateful.

    Hi gjc,
    I've sent a PM to you about a free design service you can avail of which compares the output of different solar panel systems. Using the details of your particular site you can find out how much energy different systems will produce and figure out the cost/benefit.


    Thanks!

    S.


  • Registered Users Posts: 1,382 ✭✭✭gjc


    Solar panels installed this weekend question one..... is the system a silent system or do people get noise when the pump is running. my system is not noisy but certainly is not silent (small level of noise) when the pump is running is this normal?? Ta


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


    While my pump is in the attic, when up there, I can hear it whirling away but it's just a quiet whirling, nothing more


    C


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


    championc wrote: »
    While my pump is in the attic, when up there, I can hear it whirling away but it's just a quiet whirling, nothing more


    C

    Does it save you money on water heating even with the electric pump?


  • Registered Users Posts: 1,700 ✭✭✭firemansam4


    gjc wrote: »
    Solar panels installed this weekend question one..... is the system a silent system or do people get noise when the pump is running. my system is not noisy but certainly is not silent (small level of noise) when the pump is running is this normal?? Ta

    The pumps usually make a small swishing sound but it shouldn't be very loud at all, but sometimes slight air bubbles in the system can make them a lot louder, this will usually settle down after a while but then there are pumps that do seem to make a lot more noise than normal.
    Does it save you money on water heating even with the electric pump?

    I tried working out the cost of running a pump on the system for a year and by my estimations it worked out less than 20 euros a year. This was taking into account the amount of time they would usually be running on average every day in a year and the power of the pump which is usually set at about 50 watts or less. So from those figures I worked out how many kilowatts was used on an average year and multiplied it by the cost of a KW of electricity.


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


    And firemansam, do you get hot water all year round?


  • Registered Users Posts: 1,700 ✭✭✭firemansam4


    And firemansam, do you get hot water all year round?

    well its not going to provide you with 100 percent of your hot water needs in the winter months but most decent systems should provide between 60 - 70 percent of your hot water needs for a year, as well as having a little knock on effect of sometimes helping your heating system get up to heat a bit faster.


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


    Thanks, will put your comment behind my ear in case I ever have the money to do this.


  • Registered Users Posts: 1,382 ✭✭✭gjc


    Thanks for that feedback regarding noise of pump, the pump was only giving out a slight whirling noise there was indeed small amount of air in system which we have got rid of now...pump very quiet now...happy!!!


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


    Does it save you money on water heating even with the electric pump?

    Keep an eye on the big picture. I have been graphing my gas units usage since Jan 06. I have taken the bi-monthly readings, added up a years worth (6 bills) and divided by 365 to get a daily units average.

    So I started off in Jan 07 with about 4.8 units per day and rose to over 5.5. in Feb09 when I installed my system. May, Jul and Sep 11 have all stabilized at 4.0. So therefore, based on a running total of 6 bills, I'm down from about 2,000 units per year to about 1,450 and so, with costs per unit increasing, should turn into a pretty saving and well on it's way to paying for itself within 10 years.

    Since Feb09, my system has recorded that it has generated over 2400 hours of heat


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


    championc wrote: »
    Keep an eye on the big picture. I have been graphing my gas units usage since Jan 06. I have taken the bi-monthly readings, added up a years worth (6 bills) and divided by 365 to get a daily units average.

    So I started off in Jan 07 with about 4.8 units per day and rose to over 5.5. in Feb09 when I installed my system. May, Jul and Sep 11 have all stabilized at 4.0. So therefore, based on a running total of 6 bills, I'm down from about 2,000 units per year to about 1,450 and so, with costs per unit increasing, should turn into a pretty saving and well on it's way to paying for itself within 10 years.

    Since Feb09, my system has recorded that it has generated over 2400 hours of heat

    Wow!


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


    So by the second anniversary of it's installation, I just missed 2500 hrs by 15


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


    Now that the weather is really icy, how are your hot water solar panels performing?


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


    Here you go, the data from last Wednesday 01 Feb

    20120201.jpg


  • Registered Users Posts: 14,906 ✭✭✭✭CJhaughey


    My 400l tank is sitting at 68deg C after todays sun. Thats top of the tank, the bottom is 42deg.


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


    CJhaughey wrote: »
    My 400l tank is sitting at 68deg C after todays sun. Thats top of the tank, the bottom is 42deg.

    I assume that the sun brought the whole cylinder up to 68, and that you used some hot water, bringing cold water into the bottom of the cylinder and dropping it to 42...

    The other way this can come about is that the heating brought the top to 68 and the solar brought it to 42, but, eh, you didn't have the heating on today, surely:)


  • Registered Users Posts: 14,906 ✭✭✭✭CJhaughey


    Yep 2 kids and a dog use a bit of water especially in hot weather like this.
    It would have been a lot higher if it wasn't being used all day, I usually change the dishwasher feed over to HW this time of the year as well.
    The washing machine has hot and cold feeds so it uses what it need from each.
    Best to use it while its there.:)


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


    CJhaughey wrote: »
    Best to use it while its there.:)
    The kids were using the hot water on the water slide today & yesterday :D
    It's usually May at the earliest before this is done, though we did it in April last year.
    Bottom of 500l store was up to 69C with top at 74C this afternoon.

    I think it's 6 days since the stove was on.

    I'm delighted :)


  • Advertisement
  • Closed Accounts Posts: 11 solarstudent


    championc wrote: »
    For 300l tank I would suggest 50 tubes.

    I have 30 and 180l and on a full sunny day at present, I can raise the whole store by about 15 deg C. The highest I've been during November is about 52 deg C (good sunshine 04 - 07 Nov) with the lowest at 15 deg C. I have a combi boiler so I can send pre-heated water to the boiler to then raise it to the required 45 / 46 deg C to deliver to the taps so I am never wasting any heat really - I only heat what I use.

    Here's a pic of my data from 22 Nov 2011
    22112011.jpg

    to suggest you need 50 tubes for a 300l tank is absolutely incorrect I am afraid. if thats what you need then your system has a low efficiency and output, and therefore your installer has installed more tubes to make up for this deficit and at a greater cost to you


Advertisement