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Re: [microhydro] Re: Some thoughts on micro-hydro in South Africa

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  • Rob Landau
    Hello Nando, others. I am attaching a spreadsheet program that calculates flow and power for a turbine in metric units. I am also attaching a user s guide to
    Message 1 of 5 , Jul 10, 2013
    Hello Nando, others.

    I am attaching a spreadsheet program that calculates flow and power for a turbine in metric units.  I am also attaching a user's guide to this spreadsheet. 

    In fact it calculates two flows and powers for two situations in order to make a comparison between the two input situations easier.

    Cheers  ~Rob


    On Tue, Jul 9, 2013 at 4:18 PM, nando37 <nando37@...> wrote:
     

    LAURENCE & TO ALL:

    The best thing somebody could do is to ELICIT " Where are the details " is to start a GOOD list of details and asking what other details are needed  or what other ideas I have to think about to be able to attain the necessary "documentation" to perform all the steps to develop in this case a local hydro electric Turbine within the capabilities of your own know how and with the assistance of those that have experience.

    I have been asking  for the "details" for many, many years -- and I have been attacked directly or via the group for asking those questions and one may end up saying, well quite a few think that I am trying to "get the business for himself"  THOUGH it is well known FACT since I have said it for so many times that I do not charge anything for the assistance ( Wrong I have said :  I charge one penny per hour ) .

    In reality it has cost me hundred of dollars and accusations that I was trying to get the business and me trying to copy other designs ---  this was one of the reasons I left OTHERPOWER.COM --that had or has a moderator of dubious behavior  assisted by another one in another European country that had or has worse behavior and otherpower.com lost the  opportunity of obtaining a TPCH for a wind mill in the small size ranges.

    Returning to hydro : To develop a small hydro turbine the first step is to determine the available pressure and volume seasonally to set the upper and lower power levels available or what can be obtained in the site being developed.

    The BEST arrangement is to determine the liter/sec of GPM  with the pressure ( head ) for such site.

    Volume of water within a pipe at full flow may not be the best idea because you are not obtaining the necessary pressure to have to make the turbine to generate its peak torque, unless the turbine is designed for open flow which is the lowest power available ( in principle).

    In your case if you have 40 M^3 @ 60 meter head this is  40000 liter/3600 sec = 11.1 l/sec -- THIS is the data needed  -- trying to use the other high volume parameters the computation may become more complicated and may cause many more errors

    So for your site  the water volume is 11.1 to  11.1 *60/40 = 16.666 == OR  11.1 to 16.66 l/s then the NEED to determine the penstock length , here you say around 1 km = 1000 meters  and in this case the need to determine the water friction losses due to the water velocity inside the pipe to find the head losses to find the NET  head the penstock may have

    When there are changes in pipe diameters then the need to determine the head losses at each diameter change and the determination  of what type of diameter changes and how was done because the common error of starting at the intake with a diameter then changing to a greater diameter down the head -- that can make the system useless sometimes-- it should be done the opposite largest diameter at the intake  then later maybe if absolutely necessary to smaller diameter if the pressure or volume limitations have to be imposed,

    We may need to assume certain minimum head losses, let's say 5 % of head -- in 60 meter head represents 3 meters  -- that  for 1000 meters penstock the losses in reality are too small indicating that the water flow will be very low ( the need to know the head losses versus  water flow calculations is here sometimes a bit to complicated 

    www.h-hydro.com site of Joe Hartvigsen has an excellent  Excel program that assists in the pipe flow and head calculations to obtain the best power curve for the site in question.  -- Unhappily JOE kept the calculations in the English system and did not make changes to use the METRIC SYSTEM a more logical system and I have been procrastinating for a long time in doing the necessary conversions steps to make it either way or to have two systems .

    Since this is a system to have a double duty, irrigation and power generation then some constrains are needed or other decisions to have either one fully or both partially effective or one partial and the second fully ( in this case irrigation should be the primary condition).

    I need a detailed description of the system from intake to the 2 bar irrigation with all the parameters to see what can be done , what can be obtained and what minimum changes may need to have to optimize both systems or again define the working parameters for each system.

    Anything I say here may be wrong in the installation of the system with dual capabilities.

    START by knowing and informing the DOLLAR exchange values with your currency to have a point of reference for  financial calculations.

    Nando





     

    On 7/9/2013 01:01, lombardm56 wrote:
     

    Nando - I thought my post would elicit your "where are the details?!" response. We, as do many farms around here have irrigation water under pressure in pipes available in winter. On our farm we would have around 40-60m3/hr at 60m head (in a 4" pipe). My idea was to make a 3-5kW system (the cost difference between a 3 and 5kW 2nd hand induction motor would not be great). Also standardizing would make manufacturing copies easier. I have ordered 24 greanspoons, arbor and 2 12.7mm (1/2") nozzles from Joe. Adjustments can be made by having between 1 and 4 nozzles and changing nozzle sizes.

    Regarding "sell the idea": I want to sell it firstly to myself - ie. prove to myself what is possible and that I can do it, also to see first hand what the costs are if do it myself. Once I have something to demonstrate I can show others. Micro-hydro it not nearly as well known here as in the US, most people would not know where to start.

    Nando "The ideal controller is the one that uses the zero crossing to do the TRIAC ballast loading changes to avoid a lot of noise in the power voltage" is music to my ears." . Where do I find such a controller - or the plans for such a controller. I do not have the knowledge to design such a controller, and the only plans for a controller are those for the hummingbird - that is why I have decided to try and build that.

    This is a project of passion - I would like to end up with a turgo model, a banki version, standalone or grid-tie. For standalone I need a dump-load controller and for grid-tie I need the safety switchgear that isolates the grid in case of grid-failure.

    The controllers on the web I have seen so far are

    http://www.powerflow.co.nz/
    http://www.renerconsys.com/
    http://www.retraceelectronics.com/Brochures/Brochure%20ELC%205i.pdf

    The powerflo costs about ZAR7500 . I would like to make as much myself to keep costs down. The parts for the hummingbird cost about R1600 so far - I have yet to build it though.

    --

    Regards
    Laurence



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