Two high-rise apartment buildings in New York City’s (NYC) Bronx borough are revolutionizing the way water is heated by combining wastewater energy transfer and geothermal technologies. The Amalgamated Housing Cooperative, made up of two 20-story affordable housing towers, is transitioning from fossil fuel-powered steam heat by installing a new geothermal capture system from SHARC Energy Systems.
The company combines underground geothermal energy with power captured from the building’s wastewater as it flows through the pipes. The system works in both warm and cold climates and may provide a remarkable solution to shrinking large buildings’ carbon footprints.
The Amalgamated Housing co-op is using funds from a $3 million state grant to explore the effectiveness of combining these two technologies into an efficient wastewater heat recovery system that can be used globally. With more than 350 billion kilowatt-hours of energy from the heat being dumped into American sewers annually, it’s a seemingly limitless sustainable powerhouse resource.
“It’s just this tremendous energy source,” said Lynn Mueller, Vancouver-based SHARC’s CEO. “The energy never leaves the building.”
This circular approach works thanks to 14-foot-deep tanks installed in a building’s basement. There, wastewater is cleaned before it goes through a heat exchanger, which captures the heat before transferring it to the building’s HVAC system. After the heat is removed, the wastewater continues onto the sewer.
In mild climates, that alone is enough to heat the building. SHARC drills holes deep into the earth in colder climates to access the ground’s steadier and warmer temperature. Drilling down means the system can work in densely populated cities.
With cities like Manhattan requiring large buildings to cut emissions by 40% before the end of the decade, technologies such as SHARC’s system are taking center stage.
Some city landmarks, such as St. Patrick’s Cathedral, are already using geothermal technology to stay warm. The move to the new technology may mean savings for residents, who will not be charged for the technology and may see significant cost reductions in their utility bills.
“The … system is a worldwide opportunity and a blueprint for what an energy-resilient, cost-effective, and carbon-free system should look like,” Mueller said. “This is just the beginning for the partnership between wastewater energy transfer and geothermal.”
“We’ll be saving money and the environment,” said Charles Zsebedics, Amalgamated Housing property manager. “Some building boards look at the emissions cut as a daunting mandate, but this board sees it as the opposite — as a chance to embrace emerging technologies to electrify our buildings and become carbon neutral.”