TRAVIS CANTY, Texas (KXAN) — After nearly an entire summer without rain, storm clouds finally rolled over Texas this week. The rain brought with it cold temperatures that had been absent for months. While many looked to the sky for relief, the residents of Whisper Valley looked underground.
“It’s literally underfoot … the ground you’re standing on,” Greg Wolfson said. He mentioned how the homes were cooled this summer: geothermal technology.
“Whether there’s snow on the ground or whether it’s 105 degrees outside, it’s always 72 or 74 degrees underground.” Wolfson is chief technology officer of EcoSmart Solutions. The company provides green building options to developers, including solar panels and geothermal technologies.
Each home at Whisper Valley, located in far eastern Travis County, is built with energy efficiency in mind, lined with solar panels, Tesla Powerwalls and EV chargers.
What is missing? Air conditioners. Instead, each home is cooled using geothermal energy. “They draw less energy than an equivalent size traditional air source heat pump or certainly an air conditioner,” Wolfson said.
How does heat from the Earth keep a home cool?
Wolfson said geothermal energy works much like an AC unit, except homes use the ground instead of a big, bulky machine.
A pipe runs from each home’s HVAC system into the ground, going down about 30 feet. So deep in the Earth the temperature remains a constant 72-74 degrees in central Texas. This temperature changes over thousands of years, but does not otherwise change.
This pipe is filled with water that is constantly flowing. According to Wolfson, water absorbs heat much more easily than air. Heat from the HVAC system is pushed into the water, which then flows underground, where it releases the heat into the ground.
“In the winter, the heat pump reverses and will basically pull the heat out of the ground and put it into the house,” Wolfson said.
The water then circulates back into the home to absorb more heat. It’s basically a cycle.
Creation of geothermal technology
The system can be accessed through a hatch in the backyard of any home. “All this connection is done before a home is built.” Bundles of cables stick out of the ground where new homes in the development will be built.
According to Wolfson, all of the neighborhood’s geothermal energy is grid-connected. All pipes are connected to an energy center that regulates the system. Cooling towers are also connected to help during extreme weather days.
Wolfson said because of the connections, if something were to happen to the home’s geothermal system, she could rely on the other homes on the network.
The mesh also means less drilling is required. Wolfson said that for most homes, it would take three holes and three pipe loops to keep those homes cool. Because of the grid, each home only requires one hole and one loop.
If the system fails, which Wolfson says is unlikely, the easiest way to repair geothermal technology is to drill a new hole.
400 homes in Whisper Valley are currently occupied, with another 400 under construction. This is the first of several development phases. They hope to build apartments and commercial space in the near future.