Do you remember, when we were young how we dug our toes in warm sand on the beach? Well, we may not have known it, but we were interacting with stored solar energy. Two young Finnish engineers from Kankaanpää, Tommi Eronen and Markku Ylönen were worrying about energy shortages. Then they wondered, could we make a sand battery to keep our toes warm all night long. Or words to that effect.
A Sand Battery Does More Than Keep Your Toes Warm
The two young men may not have been first with the idea. But they are first to produce a commercial working model. They piled 100 tons of building sand into a silo, and went live in late May. “We were talking about how – if we had the liberty to design a community for ourselves,” they explain. “How could we solve the energy problem in such a confined environment?”
Their sand battery gets super warm, using green energy from wind and solar in daytime. In fact, it gets positively hot at 500° C / 932° F, and can retain the heat for several months. “We wanted to find something that can be sourced nearly everywhere in the world,” they explain. “But is sand as ubiquitous as we might think?”
Releasing Energy From Sand Is Really Simple Too
Sand is not a super conductor. The battery heats the sand through resistive heating, whereby an electric current passes through causing friction. A heat exchanger then circulates the hot air through the silo.
The battery releases the hot air when required to warm water in the district heating network. Local residents, offices and even the local swimming pool benefits. “There’s really nothing fancy there,” Markku Ylönen explains.
“The complex part happens on the computer. We need to know how the energy, or heat moves inside the storage, so that we know all the time how much is available and at what rate we can discharge and charge.” We’ll remember that next time we visit the beach. Insights thanks to BBC Science.
Breaking News
Texas Adds Another 200 Megawatts Storage
Grid Scale Batteries the Best Option For Boost
