Wastewater is and will always be warm, and its heat so far has usually been lost, without powering anything (but bacteria). To prevent this precious (filthy) energy go down the drain, NovaThermal Energy LLC, based in Philadelphia, wants to implement what they call a “sewage geothermal” technology, meant to recover most of it.
“It’s just like geothermal energy, but we’re using a different well source, so to speak,” said Elinor Haider, NovaThermal Energy CEO.
The philosophy is simple: wastewater picks up heat from a number of sources, including dishwashers, showers, industrial processes and “biomatter.”
It can reach 60 degrees in the winter and over 75 during the summer, so its heat can easily be extracted by a regular heat pump like those used in mainstream geothermal systems.
Before entering the pump, the wastewater is cleaned from larger debris. This step protects the heat pump from being destroyed.
NovaThermal’s project has been funded $150,000 through a federal stimulus grant, money that helped build a pilot plant at Philadelphia’s Southeast Wastewater Treatment Plant, near the Walt Whitman Bridge. The company also intends to install a commercial-sized project in Camden, NJ, at a local sewage treatment plant.
Now, the interesting news is that the technology hasn’t been invented in the U.S.. NovaThermal Energy LLC uses a Chinese patent issued to Jin Da Di Energy Engineering and Technology Co. Ltd. in Tianjin.
In fact, the Chinese company already installed their sewage geothermal system in China, where the energy extracted is used for both heating and cooling a hotel, a 1 million-square-foot train station in Beijing (imagine the size of that) and a 450,000-sq-ft high-rise apartment building in Tianjin.
Applied on U.S. soil, NovaThermal Energy’s sewage geothermal system is meant to reduce energy costs by up to 40 percent and have a return on investment period of less than eight years. This can actually happen because they are using infrastructure that is already installed, unlike Rabtherm’s, their Swedish competitor.
Now, while recovering energy from waste heat may seem like a no-brainer to some, transferring Chinese patents to be used in the U.S. is something worth noting. And the way that geothermal equipment is being put to use in a totally different (but still inhospitable) environment is brilliant.