Stories of Technology, Innovation, & Entrepreneurship in the Southeast

Knoxville Business News Tennessee Mountain Scenery Background
April 15, 2019 | Tom Ballard

Michael Garrabrant sees “light at the end of the tunnel,” but also “a lot of work to do”

By Tom Ballard, Chief Alliance Officer, PYA

“We can see a light at the end of the tunnel, but we still have a lot of work to do,” Michael Garrabrant of Stone Mountain Technologies Inc. (SMTI) told us recently.

We had followed-up with the company’s Chief Executive Officer to learn more after he presented an update at last December’s “Opportunities in Energy” forum hosted by the Tennessee Advanced Energy Business Council (TAEBC). It’s been a 10-year journey for the start-up focused on developing a new generation of thermal compressors that will be deployed as a key component of gas heat pumps for space, water and pool heating.

“We started with me, myself and I when we incorporated in September of 2008,” Garrabrant explained. Today, the Johnson City-based company has 16 full-time employees and nearly a dozen test units deployed in both residential and light commercial pilots.

“We’re getting a lot of good data from those test sites,” he said. For example, there are five homes in the Los Angeles area that are using the compressors for water heating and several in the Upper Midwest that are using them for both space and water heating and even a couple of restaurants that are using the device for both air conditioning and water.

“We had not contemplated that opportunity,” Garrabrant says of the air conditioning possibility. “We are providing air conditioning for free; they don’t have to use electricity to provide it.”

Is performance of the new compressor satisfactory?

Garrabrant cites a house in the Upper Midwest where a prototype unit had been installed. The outside temperature dropped to 30 degrees below zero during the recent Polar Vortex, yet the house remained warm.

“That was a major accomplishment,” he said. “We now have proof that it (our technology) can keep the house warm and not have a back-up heating source.” That’s huge for heat pump manufacturers seeking increased efficiency at a reduced cost.

SMTI is working with two major customers that hope to have its thermal compressors installed in their heat pumps by the end of 2020 or early in 2021. To meet those needs, Garrabrant says he and the team are now focused on “diving deep . . . optimizing our design for cost and manufacturing.”

One of the ways that the company has advanced its technology is through grants from the U.S. Department of Energy. SMTI is now working on a prototype for the National Resources Canada (NRCan). The winters are clearly more challenging in that region, and the government wants to find ways to reduce its carbon footprint.

“Canada is way ahead of the United States,” Garrabrant says in relation to carbon footprint reduction. “The government is considering mandating heat pumps by 2030. That would be a real competitive advantage for SMTI.”

There are also potential opportunities in Europe that might come 12 months or so after launching the thermal compressors here in the U.S.

SMTI recently graduated from TAEBC’s “Energy Mentor Network” that is offered in conjunction with Launch Tennessee. “It was a great experience,” Garrabrant said. “I’m very appreciative of the feedback we got and the contacts we made.”

As he moves closer and closer to full-scale production, he expects to launch a Series A funding round by mid- to late summer. With that goal in mind, Garrabrant is very pleased that SMTI was selected as one of 20 companies participating in the annual “Industry Growth Forum” hosted May 9 and 10 in Denver by the National Renewable Energy Laboratory.


Don’t Miss Out on the Southeast’s Latest Entrepreneurial, Business, & Tech News!

Sign-up to get the Teknovation Newsletter in your inbox each morning!

  • This field is for validation purposes and should be left unchanged.


No, thanks!