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Re: [microhydro] What type of generator

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  • Nando
    Wayne: Your are looking to have continuous and stable power . First you need to determine the water volume ( minimum and maximum) and the head ( height
    Message 1 of 6 , Jun 30, 2007
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      Wayne:

      Your are looking to have continuous and stable power .

      First you need to determine the water volume ( minimum and maximum) and the head ( height difference between he intake and where the turbine is located.

      This way one can suggest the best way to go.

      If you are thinking that the hydro system needs to be close to a petrol generator, you are making a mistake

      A KVA generator needs a turbine that gives you such power and boat propeller is designed to Putout power not to take input power.

      If it is run of the river system, do detail the river characteristics , depth, volume, velocity, etc.

      Nando


      ----- Original Message -----
      From: waroca2000
      To: microhydro@yahoogroups.com
      Sent: Saturday, June 30, 2007 8:35 AM
      Subject: [microhydro] What type of generator


      I am looking in to building a run of the river system on the creek out
      back of our house. However, the bottom mount generators seem to cost
      close to AU$2000 for a small one but I can get a 4kva brushless
      generator coupled to a good Robin petrol motor for around AU$600. My
      question is, could I use this 4kva generator coupled to a 14" boat
      propeller mounted on a long shaft in the creek as it seems a much more
      affordable option??

      Thank you for your consideration and assistance.
      Wayne





      [Non-text portions of this message have been removed]
    • Michael Lawley
      Hi Wayne, In short no. You have to match the rpm of the turbine to that of the generator at the correct rpm and power output. Taking a propeller at random and
      Message 2 of 6 , Jun 30, 2007
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        Hi Wayne,



        In short no. You have to match the rpm of the turbine to that of the
        generator at the correct rpm and power output.



        Taking a propeller at random and connecting it to a high speed generator
        from a small generator set is very unlikely to work and it if does it will
        not work well, unless you get very lucky.



        You really need to start with some calculations based on the energy in the
        flow, the power you can extract at the maximum rpm you can get for the
        turbine type you are considering. Then find a good generator match and do a
        few iterations.



        Once the calculations work you have a reasonable chance of making it work in
        practice.



        We have observed many practical people over the years chasing imaginary
        power.





        Regards





        Michael Lawley

        Renewable Energy Engineer

        EcoInnovation

        EcoInn/EcoBach

        671 Kent Road

        R.D.1

        New Plymouth

        New Zealand

        Phone: (NZ) 06 752 2765

        Fax: (NZ) 06 7522768

        Web site: HYPERLINK "http://www.ecoinnovation.co.nz/"www.ecoinnovation.co.nz
        or HYPERLINK "http://www.ecoinn.co.nz/"www.ecoinn.co.nz

        HYPERLINK "http://www.ecoinnovation.co.nz/pdf/Customer_comments.pdf"Customer
        Comments 50 kB PDF

        email: HYPERLINK
        "mailto:michael@..."michael@...



        _____

        From: microhydro@yahoogroups.com [mailto:microhydro@yahoogroups.com] On
        Behalf Of waroca2000
        Sent: Sunday, 1 July 2007 1:35 a.m.
        To: microhydro@yahoogroups.com
        Subject: [microhydro] What type of generator



        I am looking in to building a run of the river system on the creek out
        back of our house. However, the bottom mount generators seem to cost
        close to AU$2000 for a small one but I can get a 4kva brushless
        generator coupled to a good Robin petrol motor for around AU$600. My
        question is, could I use this 4kva generator coupled to a 14" boat
        propeller mounted on a long shaft in the creek as it seems a much more
        affordable option??

        Thank you for your consideration and assistance.
        Wayne




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        Checked by AVG Free Edition.
        Version: 7.5.476 / Virus Database: 269.9.14/880 - Release Date: 29/06/2007
        2:15 p.m.



        No virus found in this outgoing message.
        Checked by AVG Free Edition.
        Version: 7.5.476 / Virus Database: 269.9.14/880 - Release Date: 29/06/2007
        2:15 p.m.



        [Non-text portions of this message have been removed]
      • Sombre one
        Hi Wayne, First, hats off to you for the effort! It is great to see folks like those on this site taking the thought process to reality in their projects. I do
        Message 3 of 6 , Jul 1, 2007
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          Hi Wayne,

          First, hats off to you for the effort! It is great to see folks like those on this site taking the thought process to reality in their projects.

          I do agree with the few who have already responded to your project and that is it will be difficult to make a formerly petro driven alternator, connected directly to a 14" prop work in a free flowing stream.

          The petrol alternator will be a high speed unit, designed to 'start' at a fairly high speed and produce it's design output at or near the petrol engines maximum torque design speed, likely to be between 2000-3000 rpm.

          In a free flowing stream, these RMPS are difficult to do with an open propeller. However, lets try to solve problems and make something viable for you.

          First the alternator: Low speed units seem to be considerably more expensive and even harder to find than off the shelf petrol driven units. High speed untis can be used in conjuction with a ratio increase from a gearbox (expensive) or belts and pulleys. Both of which incidently, do rob you of some efficeincy, though this can be minimized with well designed and properly setup systems. I would suggest high quality belts and pulleys,Gates for example. I don't know if these folks do business in Austrailia, but they sell an alternator that could work and it is £200. http://www.machinemart.co.uk/shop/search/filter/alternators/page/1


          Here is the description of a system I designed for a friend in the US; he has a rather fast moving stream on his property in Connecticut that is approximately 10 feet wide and on average, 2 feet deep. He has a high of 3 feet deep and a low of 1 foot. He is quite reliable getting 1.5 KW and this is just about the average amount of energy he uses in his house providing nearly a net $0.00 yearly power bill.

          To minimize the negative effect of the seasonal and rather large depth change on his stream, I designed what is escentially an undershot water wheel on pontoon floats that are teathered to the banks on both sides.

          The pontoons have been designed and then ballested to make maximum use of available flow. The turbine blades (waterwheel) are 1 inch off the ground when the assembly is flat on the stream bed (low flow season) and the system floats only when at high water levels.

          We are using a toothed belt/pulley system because part of the ratio reduction system runs in the water and this avoids slippage. The water bennefits the system a bit in that it is all watercooled, the belts, pulley, bearings etc. due to direct submersion or slash. Gates on-line calculator estimates a 15% power loss. but this is acceptable in this system.

          The most difficult part of the design were the electronic controls. I had to create a system that enabled the generator to turn at 'best speed' by reducing the load, regardless the flow. Off the shelf I would imagine this would have cost him £2-£3k, but the parts I used to soldier it all together came to about £200, including the micro-controller circuit.

          It is all automated and actually quite tollerant of debris, which I was quite worried about. The fact that the turbine is steel and quite robust, it pretty much just chews through the trash and sticks floating down the stream. It has been in operation now for 2.5 years and has only stopped five times due to large logs jamming underneath. In each instance, he just lifted the system a bit from the shore by pulling on one of the teathers holding the system in place.

          Finally, I think we spent about £1200 in total, but did every bit of work ourselves.

          Best of luck and I hope you have found an idea or two for your project.

          Best regards,
          David

          Michael Lawley <ecoinn@...> wrote:
          Hi Wayne,

          In short no. You have to match the rpm of the turbine to that of the
          generator at the correct rpm and power output.

          Taking a propeller at random and connecting it to a high speed generator
          from a small generator set is very unlikely to work and it if does it will
          not work well, unless you get very lucky.

          You really need to start with some calculations based on the energy in the
          flow, the power you can extract at the maximum rpm you can get for the
          turbine type you are considering. Then find a good generator match and do a
          few iterations.

          Once the calculations work you have a reasonable chance of making it work in
          practice.

          We have observed many practical people over the years chasing imaginary
          power.

          Regards

          Michael Lawley

          Renewable Energy Engineer

          EcoInnovation

          EcoInn/EcoBach

          671 Kent Road

          R.D.1

          New Plymouth

          New Zealand

          Phone: (NZ) 06 752 2765

          Fax: (NZ) 06 7522768

          Web site: HYPERLINK "http://www.ecoinnovation.co.nz/"www.ecoinnovation.co.nz
          or HYPERLINK "http://www.ecoinn.co.nz/"www.ecoinn.co.nz

          HYPERLINK "http://www.ecoinnovation.co.nz/pdf/Customer_comments.pdf"Customer
          Comments 50 kB PDF

          email: HYPERLINK
          "mailto:michael@..."michael@...

          _____

          From: microhydro@yahoogroups.com [mailto:microhydro@yahoogroups.com] On
          Behalf Of waroca2000
          Sent: Sunday, 1 July 2007 1:35 a.m.
          To: microhydro@yahoogroups.com
          Subject: [microhydro] What type of generator

          I am looking in to building a run of the river system on the creek out
          back of our house. However, the bottom mount generators seem to cost
          close to AU$2000 for a small one but I can get a 4kva brushless
          generator coupled to a good Robin petrol motor for around AU$600. My
          question is, could I use this 4kva generator coupled to a 14" boat
          propeller mounted on a long shaft in the creek as it seems a much more
          affordable option??

          Thank you for your consideration and assistance.
          Wayne

          No virus found in this incoming message.
          Checked by AVG Free Edition.
          Version: 7.5.476 / Virus Database: 269.9.14/880 - Release Date: 29/06/2007
          2:15 p.m.

          No virus found in this outgoing message.
          Checked by AVG Free Edition.
          Version: 7.5.476 / Virus Database: 269.9.14/880 - Release Date: 29/06/2007
          2:15 p.m.


          [Non-text portions of this message have been removed]






          ---------------------------------
          Pinpoint customers who are looking for what you sell.

          [Non-text portions of this message have been removed]
        • Manfred Mornhinweg
          Hi Wayne! ... A classical example for economy of scale! For every hydro generator sold, it s likely that several thousand gasoline powered gensets are sold!
          Message 4 of 6 , Jul 1, 2007
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            Hi Wayne!

            > I am looking in to building a run of the river system on the creek out
            > back of our house. However, the bottom mount generators seem to cost
            > close to AU$2000 for a small one but I can get a 4kva brushless
            > generator coupled to a good Robin petrol motor for around AU$600.

            A classical example for economy of scale! For every hydro generator
            sold, it's likely that several thousand gasoline powered gensets are sold!

            > My
            > question is, could I use this 4kva generator coupled to a 14" boat
            > propeller mounted on a long shaft in the creek as it seems a much more
            > affordable option??

            No. There are several flaws with your proposition:

            - That generator most likely needs to run at 3000 rpm. A boat propeller
            mounted in a creek might run at 100 rpm or so, depending on the speed of
            the water. You would need an extremely fast running creek to get enough
            propeller speed for driving that generator!

            - The typical creek will never come anywhere close to 4kW output from a
            14" propeller! Again, it would have to flow extremely fast for that.
            Such a fast speed would very quickly erode the streambed, widening and
            deepening it and thus slowing down the stream!

            - A boat propeller is made as a propeller, not as a turbine. It will
            work as a turbine, but at much lower efficiency than a true turbine. The
            same is true when trying to use aircraft propellers as wind turbines.
            It's no good. They are just made the other way around!

            - The generator on that Robin motor almost certainly has only one
            bearing. To use it without the engine, you would have to make a new
            faceplate, with a shaft extension and ball bearing.

            This is just for starters. There are several more problems with your
            proposed setup!

            It would be better if you started by measuring the flow and speed of
            your creek, its dimensions, any head you might be able to get, and then
            it would be possible to start estimating how much power you could get
            from it. If it comes out attractive, then the second step would be to
            think about what kind of turbine and generator could harvest that power.

            Manfred.

            --------------------------
            Visit my hobby homepage!
            http://ludens.cl
            --------------------------
          • Wayne
            Hi all and thank you for your valuable advice. The stream I want to use has a summer flow of about 200 litres a second, (about a foot deep x 4 feet wide) and
            Message 5 of 6 , Jul 2, 2007
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              Hi all and thank you for your valuable advice. The stream I want to use
              has a summer flow of about 200 litres a second, (about a foot deep x 4
              feet wide) and a maximum winter flood flow (which happens regularly) of
              about 7 feet deep x 15 feet wide.
              The other problem I have is that as I am on the edge of town I cannot dam
              the creek.

              I guess what I need to do next is to install a pipe in the bottom of the
              creek to concentrate the flow and mount the propeller in it to see what
              revolutions the prop will generate and the amount of tourque developed.

              Then I can look for a suitable generator. Mind you, any suggestions are
              always welcome.

              Either that or I need to look at other systems such as a floating
              waterwheel as suggested by another.

              Thanks again, Wayne


              > Hi Wayne!
              >
              >> I am looking in to building a run of the river system on the creek out
              >> back of our house. However, the bottom mount generators seem to cost
              >> close to AU$2000 for a small one but I can get a 4kva brushless
              >> generator coupled to a good Robin petrol motor for around AU$600.
              >
              > A classical example for economy of scale! For every hydro generator
              > sold, it's likely that several thousand gasoline powered gensets are sold!
              >
              > > My
              >> question is, could I use this 4kva generator coupled to a 14" boat
              >> propeller mounted on a long shaft in the creek as it seems a much more
              >> affordable option??
              >
              > No. There are several flaws with your proposition:
              >
              > - That generator most likely needs to run at 3000 rpm. A boat propeller
              > mounted in a creek might run at 100 rpm or so, depending on the speed of
              > the water. You would need an extremely fast running creek to get enough
              > propeller speed for driving that generator!
              >
              > - The typical creek will never come anywhere close to 4kW output from a
              > 14" propeller! Again, it would have to flow extremely fast for that.
              > Such a fast speed would very quickly erode the streambed, widening and
              > deepening it and thus slowing down the stream!
              >
              > - A boat propeller is made as a propeller, not as a turbine. It will
              > work as a turbine, but at much lower efficiency than a true turbine. The
              > same is true when trying to use aircraft propellers as wind turbines.
              > It's no good. They are just made the other way around!
              >
              > - The generator on that Robin motor almost certainly has only one
              > bearing. To use it without the engine, you would have to make a new
              > faceplate, with a shaft extension and ball bearing.
              >
              > This is just for starters. There are several more problems with your
              > proposed setup!
              >
              > It would be better if you started by measuring the flow and speed of
              > your creek, its dimensions, any head you might be able to get, and then
              > it would be possible to start estimating how much power you could get
              > from it. If it comes out attractive, then the second step would be to
              > think about what kind of turbine and generator could harvest that power.
              >
              > Manfred.
              >
              > --------------------------
              > Visit my hobby homepage!
              > http://ludens.cl
              > --------------------------
              >
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