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Human powered refrigerator

  1. Feb 13, 2012 #1
    I make human powered machines for offgrid living and have been getting ready to start on a human powered fridge. The idea is to use a deep freezer and replace the compressor with an automotive one, and connect the shaft to pedals (might require two riders).

    1) Are the freon types compatible?
    2) Are the pressures compatible, or the compressor modify-able?
    3) Due to the surplus power, would like to charge up a large pressure tank of coolant to circulate and cool the system after riding for say 5 minutes.

    Any thoughts smart guys/gals?

    thanks for any insights into this!
  2. jcsd
  3. Feb 18, 2012 #2
    If it was me, I would rethink that power source. Humans basically working out on treadmills in order to keep said food cold are going to consume a lot of the said food. Not good for a survival point either- you need to be able to do other things yes?

    As far as I know the freon is not compatible either, not sure if the lines would need changing or not? They have different viscosity so the port sizes are what matter I think, to avoid any plugs.

    Those systems dont like start/stop conditions either.. So human power is going to be very uneven.

    Assuming a creek is nearby, you could have cold water being pumped through the unit to minimize work on the cooling system. Then run a 12v compressor or belt drive an automotive one whenever the temperature rises too much?
  4. Feb 19, 2012 #3
    let's say a fridge uses 200 KwH of power (a very generous rounding)

    one joule/second = 1 watt
    1000*60*60 j/s = 1 kwh
    a 200 kwH fridge needs 1000*200 kw every hour. that's 1000*200/(60^2) = 55 joules/second

    let's say an out-of-shape cyclist can generate 200 watts
    that's 200 joules/second

    you'd have to ride 6 hours/day to run the fridge (assuming you have a flywheel, or battery, or something harnessing the spare energy)
    i guess 3 hours in the morning, and 3 hours before bed seem feasible
    it'll probably be closer to 8 hours/day
  5. Feb 21, 2012 #4
    Liked the idea but as the above two posters said, the amount of energy to be put in by humans hardly justifies its feasibility.
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