Sand battery more experiments.

  • Sand battery more experiments.

    Posted by MartHale7 on December 22, 2023 at 5:32 pm

    i am coming back to my sand battery experiments.

    I have changed direction with my goals as I have found the pex pipe for water is not rated for over 180 degrees, so I have removed the pex from my system.

    I found that the burner when surrounded with sand will burn out. The water heater element lasted months, but it burnt out and produced a small amount of glass.

    The pot I had burnt out -> Stainless steel pot.

    So I have swapped out the stainless steel pot for a cast iron pot. The burner comes from a single stove top burner from the dollar store.

    I have had other ideas of how to heat the inside of the sand battery, with 1) friction. 2) use the sand mixed with an electrolyte of some type to create a huge resistor perhaps graphite? But for right now I am still going to use the burner….. I have had thoughts of an inductive heater that runs off straight DC…

    This newest setup has the following.

    A stainless pot filled with sand in the bottom of the trash can. Above this is the single burner which I removed the plastic from and it is hooked up straight to my solar panels. The present one is showing signs of wear from where the sand leaked out of the stainless pot when it developed holes.

    So far in my testing I am hitting from 200 – 250 degrees inside the trash can which is inside a 55 gal barrel which has insulation around the outside of that, for over 6 hours of time.

    My goal is to get a cheap heater element that will be long lasting….. I am picking up cheap cookers from the thrift store as of now for testing.

    I have noticed the present setup has dried out the sand very very well, so I am thinking this could be used to dry firewood. I don’t want to cook in it as it is a galvanized trash can so fumes I don’t want on my food, if I remove that, then I might consider cooking food again.

    I want to see how the temp is affected by removing sand from the equation. I have had fun with this experiment as it has taught me the limitations of sand batteries, and some ideas on how to make them better.

    MartHale7 replied 1 month ago 3 Members · 6 Replies
  • 6 Replies
  • EvW

    Member
    December 22, 2023 at 7:56 pm

    Good luck!

    • MartHale7

      Member
      December 22, 2023 at 10:44 pm

      Thank you, I love to play with toys.

  • Njorun38

    Member
    December 22, 2023 at 8:55 pm

    Good luck! Let us know how the next experiment goes

    • MartHale7

      Member
      December 22, 2023 at 10:44 pm

      Will do.

  • MartHale7

    Member
    December 31, 2023 at 8:35 pm

    Today I decided to try using my solar sand battery to dry out stock I have for my kelly kettle. I put the semi moist wood in, and at end of the day I pulled out crispy dry kindling.

    With my tricks I have learned I was able to boil 6 cups of water in 5 and 1/2 minutes with the dry wood.

    I was wrong about how many solar panels I am using I have 3 240 watt panels hooked up to the single burner…. So at max 720 watts of power….

    So… At last my toy moves to being a dehydrator. I was using 5 panels before… I think because I had the nicrome wire part of the burner too insulated with sand that, and spilling sand on the burner is what killed it.

    Now I can dehydrate more things…

    I am getting like 6 hours of time at temps from 200 – 340 degrees F. Using 3 solar panels and 5 gallons of dry sand. Now, I believe I just need to improve insulation… I am thinking layers of cardboard around the outside should do the trick as I have an airgap between the trash can and the 55 gal barrel which is holding up well…

  • MartHale7

    Member
    January 28, 2024 at 8:14 pm

    Today hit the highest temp ever, over 803 deg F….

    It was a bright sunny day, I had replaced the wire with silicon covered wire..

    Also I removed some of the sand and I put a 12 inch long rail road rail in the dutch oven with some sand inside.

    I believe if I opened this up and put a pot on the top with water it would instantly boil……

    I am most curious how long this will take to cool off……

    The real questions I have now is how much mass can I add to this equation, as bricks or steel, and how does that affect the cool off time?

    Hitting this temp blew me away. Tomorrow is another sunny day, I imagine I will have some residual heat and the temp will get higher.

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