Announcement Announcement Module
Collapse
No announcement yet.
Thoughts on solar hot water heaters Page Title Module
Move Remove Collapse
X
Conversation Detail Module
Collapse
  • Filter
  • Time
  • Show
Clear All
new posts

  • Thoughts on solar hot water heaters

    I have a solar hot water heater system installed in my house. It works in conjunction with an electric water heater. Well, I'm planning on replacing the roof this week, and I am debating on whether to just toss the solar system. I will have to remove the panels anyways to lay down the new roof. I just don't know if it is worth reinstalling the panels. The system is 26 years old and the circulator pump seems to run constantly. The pump pulls less than 1 amp at 115volts. What is the typical life expectancy of a solar hot water system. Are they even cost effective anymore?
    Last edited by fronty; 06-07-2007, 09:46 PM.

  • #2
    Re: Thoughts on solar hot water heaters

    The pump should run almost continuous during the day depending on the control package.
    26 year old system might have another 10 years or more left in it.
    What's the condition of the brackets and panels? Are they cloudy?
    Either way you will have to drain the glycol from the system and store it for reuse or dispose of it legally. That can be expensive.

    Comment


    • #3
      Re: Thoughts on solar hot water heaters

      Originally posted by plumberscrack View Post
      The pump should run almost continuous during the day depending on the control package.
      26 year old system might have another 10 years or more left in it.
      What's the condition of the brackets and panels? Are they cloudy?
      Either way you will have to drain the glycol from the system and store it for reuse or dispose of it legally. That can be expensive.
      Yes, the panels are cloudy. I felt the recirculating tubes and they are not warm/hot. I'm not sure if this system is still working.

      Comment


      • #4
        Re: Thoughts on solar hot water heaters

        Originally posted by fronty View Post
        Yes, the panels are cloudy. I felt the recirculating tubes and they are not warm/hot. I'm not sure if this system is still working.
        Cloudy panels? that makes your decision alot easier doesn't it?

        Too bad really I've done a bit of solar work and hate to see someone walk away from it.

        Comment


        • #5
          Re: Thoughts on solar hot water heaters

          Can you buff up the panels with an automotive type paint restorer (fine polishing grit in solution)? I did this to my clouded and sand blasted headlights and they came out like new.

          Comment


          • #6
            Re: Thoughts on solar hot water heaters

            I think Wayne is refering to Rubbing Compound which you can buy at auto parts stores and sometimes I've seen it at Walmart. It's great for removing scratches as long as you're willing to do some work rubbing away with a rag. When done, wash it off and rinse. Then have a look.

            By the way it also comes as paste in small cans like auto wax does.
            Attached Files

            Comment


            • #7
              Re: Thoughts on solar hot water heaters

              Since you have been using this system for so long you may have lost track of how much (if at all recently) money or energy the solar system saves you.

              Before you give up on it altogether, why not do some simple research. Shut the system down for a month and see what you electric bill is. Then compare it to last months and also the same month in past years (however far back your records go). Is it higher or lower? From this simple comparison is the system saving you enough money to justify repair/replacement of the panels?

              Are you losing money (burning kilowatts on the circular and not getting anything worthwhile in return)? Maybe its time for a completely new system or do away with it entirely if the cost to bring its performance back it prohibitive to you.
              ---------------
              Light is faster than sound. That's why some people seem really bright until you hear them speak.
              ---------------
              “If I had my life to live over again, I'd be a plumber.” - Albert Einstein
              ---------
              "Its a table saw.... Do you know where your fingers are?"
              ---------
              sigpic http://www.helmetstohardhats.com/

              Comment


              • #8
                Re: Thoughts on solar hot water heaters

                truthfully, the savings for a residential hot water solar system are not there.

                back in the 70's when they had all the tax credits, it paid. today the cost for a replacement tank is more than any savings a residential customer will receive.

                now solar for a pool still pays. quick payback and cheep to install and maintain.

                solar electric. still a good tax incentive and a relative short payback period.

                solar domestic water heating. a big joke no tax incentives and you'll never recoupe your investment.

                rick.
                phoebe it is

                Comment


                • #9
                  Re: Thoughts on solar hot water heaters

                  I appreciate the help guys. I haven't even looked into this system yet. I guess I was wrong in the way I was thinking this thing worked. I thought that the water from the expansion tank just circulated up through the panels. I didn't know that glycol was involved and a heat exchange process. Well, I'll snap a few pics tomorrow. My hot water heater is in the attic and the solar water tank is HUGE. If I remove the solar system, I'm just going to install a new water heater in its place and eliminate the water heater in the attic (repipe everything). Well, it has been pretty hot these days. Couldn't I just take a temp reading at the ingoing and outgoing pipes. I don't really know how to even diagnose it to see if it is still functional at this point. Can someone give me a quick run through of how it is supposed to operate?

                  Comment


                  • #10
                    Re: Thoughts on solar hot water heaters

                    i doubt that your system uses glycol. this is a domestic hot system right

                    i wouldn't spend the money on reinstalling it on a new roof. i doubt that the utility charge at the end of the month will change much.

                    rick.
                    phoebe it is

                    Comment


                    • #11
                      Re: Thoughts on solar hot water heaters

                      Originally posted by PLUMBER RICK View Post
                      i doubt that your system uses glycol. this is a domestic hot system right

                      i wouldn't spend the money on reinstalling it on a new roof. i doubt that the utility charge at the end of the month will change much.

                      rick.
                      fronty does not say where he lives but it would not be unusual to have a shell and tube exchanger using Propylene Glycol Antifreeze as a transfer liquid for a domsetic water solar heating.

                      Mark
                      "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

                      I never lost a cent on the jobs I didn't get!

                      Comment


                      • #12
                        Re: Thoughts on solar hot water heaters

                        I agree with Mark if the location is anywhere where the temperature could approach freezing that a glycol system would be needed with a heat exchanger in that case.

                        Rick, you said you don't think the electric bill would show much difference w/o the solar heater in service. If that is the case then I would not bother with it. Too much maintenance and extra equipment to maintain for no return. Here in NJ I don't think a solar HW heater would pay back fast enough.

                        I don't think you'll gain enough information measuring the input and output temperatures over a short period to know if the system is working or has some level of efficiency at which you could say it is profitable to continue to operate it.


                        I'd like to put in a PV system and help cut my dependance on the grid for all my power. I don't know if we will be in this house long enough to make it worthwhile though, so maybe the next home. I am just beginning to investigate systems and have a plenty of questions.

                        One of the four utilities that operates in NJ has said they will provide up to 100 million dollars in loans to residential and business customers for solar systems.
                        ---------------
                        Light is faster than sound. That's why some people seem really bright until you hear them speak.
                        ---------------
                        “If I had my life to live over again, I'd be a plumber.” - Albert Einstein
                        ---------
                        "Its a table saw.... Do you know where your fingers are?"
                        ---------
                        sigpic http://www.helmetstohardhats.com/

                        Comment


                        • #13
                          Re: Thoughts on solar hot water heaters

                          Sorry, I live in central Florida. This is a residential installation. I'll post pics tomorrow of the system.

                          Comment


                          • #14
                            Re: Thoughts on solar hot water heaters

                            I'm with Rick get rid of it.
                            THE GLASS IS ALWAYS HALF FULL

                            Comment


                            • #15
                              Re: Thoughts on solar hot water heaters

                              Originally posted by PLUMBER RICK View Post
                              i doubt that your system uses glycol. this is a domestic hot system right
                              rick.
                              Frankly I'd be surprised if it didn't use Glycol. Most solar systems do and it probably wouldn't have lasted 26 years without it.

                              Without seeing your system but I'm guessing you have a huge insulated storage tank which has a heat exchanger inside of it and a separate electric heater next to it. Glycol fluid is circulated through the heat exchanger up and across the panels on the roof to be heated . The hot Glycol on a sunny day can be over 150 degrees. This heats the water inside the storage tank. Now this process takes a long time so if you are using more hot water than the panels can recover or on a cloudy day the electric water heater kicks in. The beauty is you are only paying for the circ. pump to run. The reason why I asked you about the cloudy panels this reduces the efficiency of the system. Not enough heat transfer to the fluid. So you felt the pipes and neither one was even warm. Even a really poor panel system with produce heat so my guess it something else is wrong. First confirm that the pump is running. Now look on the roof for a oily stain near the panels where the glycol would have leaked out from maybe some storm damage? While you are up there see if the panels have a small bleed valve. Your system may just be low on Glycol. If so you'll have to pump some in there from the attic while someone else bleeds the air out. It would only be low if there was a leak or someone accidently drained some out through a valve. I don't know why your system doesn't have a temperature gauge installed- it should.

                              Now with all that being said if you can get it working with little or no money then I say reinstall the panels after the new roof goes on.

                              But if you are a wealthy tree hugging ex hippy eco-maniac looking to reduce his carbon footprint then a new system can be purchased for about 8k.

                              ~Bill
                              Last edited by plumberscrack; 06-07-2007, 03:42 PM.

                              Comment

                              Working...
                              X