Climate & Energy Ohio University

Ping’s Green Machines: The Science Behind Cardio Lookout

Sophomore Emily Brandenburg (left) and Freshman Casey Harchaoui (right) working out and creating energy at Ping’s Cardio Lookout. Photo by CG Science Writer Elizabeth Cychosz.

By Elizabeth Cychosz, CG Science

Through the front doors, past the desk, up the stairs, and around the corner. There.
Twenty Precor ellipticals face the floor-to-ceiling windows overlooking Ohio University’s Ping
Recreation Center’s front lawn, and overworked students line up to burn off the stress of the day.
This is Cardio Lookout, known for its view and for those hand-scrawled signs boasting the
number of kilowatt hours gym-goers have contributed to the electrical grid.

Ping Director Hafedh Benhadj identifies these ellipticals as one of the most popular
machines, perhaps because they are so eco-conscious-friendly. “We thought it [was] a good idea
to contribute to the green movement in a tangible way where our students can have an impact on
what they do,” he said. “In this case, a work-out can generate electricity.”

Cardio Lookout arrived to the Ping scene in 2009. ReRev, of Sunquest Energy, retrofitted
the ellipticals with its ReCardio system. According to Sunquest Energy’s vice president of sales,
Glen Johansen, the system takes the natural leftover kinetic energy from a work-out, converts it
into a form electrical circuits can use, and feeds that energy back into the building.

“There’s energy that’s wasted now, [and] we’re capturing it and putting it back into our
grid,” Johansen said. “Buildings are often big consumers of energy. That’s where we want to
put the energy back.”

And back it goes. Before being fitted for ReRev, ellipticals are powered through wiring,
and their energy consumption shows up on Ping’s electrical bill. ReRev makes these same
ellipticals self-sustaining with leftover energy, only using 10% of the ultimate wattage for their
own power.

“We harness energy that was wasted in the form of heat into the room … and just burnt
off through resistors,” said Johansen. “The energy, as you work out, goes back to a box, and
we convert that energy. And that box, then, transfers it into the building, and that will allow it to
be absorbed into the building’s power grid.” This conversion refers to ReRev’s patent-pending
process in which kinetic and heat energy becomes direct current (DC) and then alternating
current (AC) — something the building can actually use. “In essence, we’re creating a kind of
micro-wind-farm, if you will. You’ve got all these little generators in the room that are spinning
from people’s workouts, and we’re harnessing that energy for them,” said Johansen.

ReCardio works best on a commercial scale. The retrofitting process involves rewiring
these machines individually and connecting them to a large unit that does the conversion. This
unit makes the system cost-prohibitive on a small-scale, but works well in a commercial gym

In 30 minutes on one of these retrofitted machines, one person can put 50 watt hours
back into the grid — enough energy to power a laptop for an hour or a CFL light bulb for two
and a half hours. Last school year, from July through the end of May, Ping patrons produced 400
kilowatt hours on the ellipticals at Cardio Lookout.

ReRev has been working to implement its system onto other exercise machines, as well,
like treadmills. “Treadmills are really unique, because they have a motor in them that requires
that they deliver a steady pace for people,” said Johansen. “But this treadmill is self-powered,
so, rather than consuming three to four hundred dollars a year in electricity, this one doesn’t take

According to Benhadj, Ping does not have plans at this time to expand its storage of
ReCardio machines because of funding and space reasons. But for now, for those who are
looking for a way to spend rainy days or winter months getting “green” exercise, Cardio Lookout
is the place to be.