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August 30, 2017 | Tom Ballard

Garrabrant approaching a decade of work on technology about ready for the market

SMTI(EDITOR’S NOTE: This is another in our series of articles spotlighting Northeast Tennessee entrepreneurs. We also recently posted this article about a grant that Stone Mountain Technologies Inc. received after this article was finalized.)

By Tom Ballard, Chief Alliance Officer, PYA

Michael Garrabrant of Stone Mountain Technologies, Inc. (SMTI) is rapidly approaching a decade of work on an energy efficient technology that he hopes will be commercialized by late 2019 or 2020.

The Johnson City-based entrepreneur first shared his vision for the start-up in this early 2015 article on, and we had a chance to get an update from Garrabrant during a recent visit to Northeast Tennessee.

“We are ready to go,” he says after about $7 million of investment, mostly through government-funded research and development from the U.S. Department of Energy (DOE) and gas utilities, as well as the Army. “The next round of field testing will validate the performance and reliability of the technology.”

Between now and the end of 2017, Garrabrant and his team of 10 employees are completing a dozen units of the device they call the SMTI Thermal Compressor. Ultimately, it will be a component of gas heat pumps for space, water and pool heating made by large Original Equipment Manufacturers (OEMs).

“Our heat pump technology functions like a boiler that sits outside the building (of a user),” he explains. For a home, the gas heat pump can replace the function of a gas furnace and water heater, reducing energy costs from 30 to 50 percent while providing warm temperatures even on very cold nights.

Field testing of the latest iteration of the technology will begin in 2018, and it will include two full-service restaurants that use 2,000 to 4,000 gallons of water a day.

“While we’re heating water, we’re also going to provide air conditioning for the kitchen,” Garrabrant explained. “We’re providing a savings on the gas bill for heating and electricity for cooling. We hope to show a payback of about one to two years.”

SMTI just finished work on a 140,000 Btu/hr GAHP (gas fired absorption heat pump) under a Cooperative Research and Development Agreement with Oak Ridge National Laboratory. The commercial-sized prototype achieved a 1.41 COP (coefficient of performance). In essence, the higher the COP, the lower the cost of operating a unit.

The results obviously translate into a value for the consumer, but there are also important benefits to the OEMs that SMTI is targeting for sales.

“They are looking for a (product) differentiator for the consumer as DOE raises efficiency standards higher and higher,” Garrabrant says. “They (efficiency standards) are almost at max already.”

The other benefit to OEMs is offsetting those who complain about too much use of natural gas.

“They can put a much better solution on the market that is more environmentally friendly and cheaper,” Garrabrant explains.

International markets are also a key target for SMTI.

“The top five space heating countries in Europe are France, Germany, the Netherlands, Northern Italy and the Netherlands,” Garrabrant says. With gas and electricity prices between one and half and two times the costs in the U.S., there is an even faster payback opportunity on the investment in the new SMTI technology.

“As European Union countries impose caps on energy usage in new construction, we will be a most cost-effective option,” he says, noting that the SMTI technology is considered renewable in Europe.

There’s also Asia – China, Japan and Korea – that offers significant growth opportunities.

As Garrabrant looks to the future, he’s exploring a manufacturing base in Northeast Tennessee from which he would supply the compressor to OEMs. He’s also getting serious about a Series A round of $2 to $2.5 million.

The company has one issued patent, four applications that have been filed, and another that will be filed as a provisional later this year.

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