One of my favorite projects at this year’s Science Fair was one that proposed to harvest useful energy from typical playground equipment.  Many pieces of playground equipment convert stored chemical energy in children’s bodies into kinetic energy.  The Science Fair project proposed to convert that kinetic energy into electricity through a simple turbine, much like a windmill.

The sample equipment identified was a typical merry go round.  This was indeed a good choice, as a merry go round concentrates all that energy on the axle buried in the ground, where a turbine could conceivably convert some of that energy into electricity.  Other playground devices would be harder to harvest energy from because there is no single point where energy is focused.  Swing sets are an obvious example.

Suppose all the kinetic energy of a playground could be captured?  How much energy is available?  An average, active, 6 year old consumes approximately  1,800 calories per day.  If that kid weighs 80 pounds and plays hard for 40 minutes, he may burn 200 calories.  An average suburban elementary school holds approximately 600students. So, the maximum playground energy, given one recess per child per day, would be 120,000 calories.  That equals 196 kWh.  A typical school in Colorado consumes .13 kWh per square foot per day, or 9,750 kWh for the entire building per day.

So, capturing playground energy could reduce school energy consumption by 2%.  That’s not a lot, but it’s a start, and it costs less than pv panels.  But, we’d have to think of another name for playgrounds.  We need something that sounds technical.  For the time being, I’d suggest Kinetic Energy Recovery Zones – KERV’s for short.  I can see that on our site plans already!

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