After years of sweating obnoxiously while cross-training, I recently discovered a novel feature of the new exercise equipment at the Hartford Hospital gym: all the machines have cooling fans embedded in the console that blow cold air directly at the user. This of course got me thinking about how great it would be if these cooling fans could be driven in real-time by the mechanical work of the user. How efficient to have the power we produce through exercise be harnessed for beneficial means to reduce the environmental footprint of a piece of gym equipment!
Full disclosure: I’m not the first to think this way. My colleague Amanda sent me this article by Tom Gibson recently, which details several start-up companies that convert gym equipment into power-producing machines that generate small amounts of electricity. In the most basic sense, entrepeneurs have recognized that attaching a generator to an elliptical machine, stationary bike or treadmill can generate 50 to 150 watts of power during an hour of strenuous exercise. An elite athlete may be able to produce close to 400 watts, more than half a horsepower! So is it worth it? What can that amount of power produce? According to Gibson, “if the average piece of exercise equipment is in use 5 hours a day, 365 days a year, generating 100 watts electricity/user, that machine creates some 183 kilowatt-hours of electricity a year. Commercial power costs about 10 cents per kilowatt-hour on average in the United States, so the electricity produced in a year from one machine is worth about US $18 dollars.” Given that it costs a gym about $500-$1000 to modify each exercise machine, saving $18 a year would take decades to offset the initial investment.
But thinking a little more creatively, what if we just reduced energy redundancies in exercise machines so that we could use our power to cool ourselves, listen to music and watch TV while exercising? According to this data visualization from GE looking at the energy use of household appliances, a standard tv requires 150 watts of energy, a portable fan requires 100 watts of energy, and a stereo somewhere been 7-60 watts. With Northeast Utilities sponsoring the Hartford Marathon this year, and an increasing focus on “green” races and events, it seems a better time than ever to consider how to combine environmental, health and cost efficiencies into capitalizing on the energy produced through exercise.