Home Forums Permaculture Discussion Forum Water to store solar electricity

This topic contains 8 replies, has 7 voices, and was last updated by  Miro 20 hours, 56 minutes ago.

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  • #12477

    Paul
    Participant

    Hi
    Has anyone got practical experience in pumping water up hill using abundent solar energy and running it back down through a small turbine at night?
    Thanks heaps
    Paul

    #12660

    Henry J
    Participant

    Not personally, but I would have assumed the costs involved would make it more profitable to sell it back to the the grid (unless you have a turbine etc already)

    #12737

    Meghan
    Participant

    Paul,

    You should do it! And let us know what you find out :)

    Meghan

    #13031

    Elmer
    Participant

    It would probably pump better with a windmill into a water tank than a solar pump (If you have the space to do this.)

    Each option is pricey.

    #13096

    Paul
    Participant

    Thanks for the replys.
    Yeah I think I’ll give it a go. Grid power is too far away and I have no desire to play their game anyway. The creek is low in the valley so wind is not regular and gusting. A ram pump will work for over 6 months of the year but for the rest solar is abundant cause when te creeks not flowing well the sun is out in force. I’ve got a few cheap ($20) 12v diaphram pump that can pump up to 1mpa in small volumes 4l/m which I want to set up for the water supply on the top of the ridge at least 100m elevation above the creek and use 3 of them to get the water up that high. Then I’ll use the same pipe to run water back down through a home made turbine on a car alternator. Try this out as a test run and if it has potential put some bigger pumps with bigger solar panels and more storage up high. I don’t mind even > 50% loss if I can avoid the expensive and consumable batteries which I’m replacing. I’m thinking I might need a small deep cycle as a power buffer and some voltage switch to start the water flow and alternator when the voltage of that battery drops low. Enjoy.

    #13133

    Henry J
    Participant

    Good luck with your mill. Other ideas to store energy could be heat in bricks or running a compressor with a tank. You can run a suprising amount of tools on compressed air. I looked into it more when Bill Mollison says about building a trompe (an air compressing device with no moving parts on a river) in one of his videos.

    #13314

    Jacqueline
    Participant

    You could use a solar to pump water up hill then run it down through a turbine to get some energy for however long the water lasts or you could perhaps use the solar to directly charge 12volt batteries that are then used to power a site. Another method to get water up hill may be focused sunlight on a copper pipe. This causes water to boil and the steam rises then use a still type device to cool the water at the other end so it drips into the catchment area. I suspect both the methods I suggest here will cost less than a solar panel or wind turbine and be more efficient in that the processes are shorter..

    This video shows how heat can be used to cause water to pump quite quickly https://www.youtube.com/watch?v=rrGMidc_P7s hope it gives you some ideas

    #13350

    Neil
    Participant

    Would be better using a diesel pump/motor unit that has been modded for biofuel or some such (or a Stirling, whatever you got handy). Problem to this is that it encourages water usage to get sufficient charge/running time=empty water tanks. Fit an alternator/turbine to your outlet by all means but only use it as a battery top-up.

    #16777

    Miro
    Participant

    Hi Paul,

    When building my own system i first wanted to go off-grid. So i implemented a battery bank, charge controller, inverter, panels and so on. The panels were super expensive so I started small. I refitted lights superefficient appliances and so on as every watt saved was a watt not needing to be captured… I had to buy many panels as the batts just weren’t being charged. Eventually i reached a plateau and i decided to get a small gridfeed inverter to dump excess charge back in the grid. I then had a bank failure and as i rewired the system to run partially off the grid (i live in the city) i noticed that i was feeding the grid way more kwh than when i had the batts on line. I did soe calculations and figured that the battery bank is a rather nefficient beast and for every kwh pulled out much more has to be fed in. The net result for me was to use the grid as a battery bank as this setup is way more efficient whilst I am in town. Your water pump setup is one such battery and I am pondering about the efficiency of such a setup. If you haea surplus of power above your daily needs by all means put it to use but other than this I think the generation and pumping losses would make it a poor/inefficient battery. You would really need to put on many extra panels just to get sufficient water up hill to still give you meaningful power levels when generating.

    Keep thinking tho because somehow we need to get power happening at night.

    I was looking into fuel cells as little units were becoming available at local electronic store. The added bonus is that they can be used as generators by adding fuel. Ie add alcohol or methane and away they go…. Should be quite efficient.. I’ve yet to see actual numbers. Another thing I was thinking that by fermenting your food wastes prior to composting and return to earth we may be ave to either get methane or alcohol either can be used a fuel in a fuelcell or an appropriately adapted generator. What are your thoughts?

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