Bill Bradley’s Testimony to THE UNDERGROUND’S CLIMATE CONTROL
By STUART MOORE
Photograph by Anthony Scarlati
At the center of our earth’s core, the temperature is hotter than the surface of the sun. Here in Middle Tennessee, however, dig anywhere from three to five feet down or deeper, and depending upon the composition of the soil, the temperature is a constant 55 to 60 degrees. That consistency makes possible the utilization of geothermal heating and cooling for our homes. The term “geothermal” is a misnomer here in Tennessee, (think Iceland), but it has become the go-to term for using the earth as an energy source or energy saving mechanism.
A Williamson County resident for over a dozen years, Bill Bradley installed his first geothermal system in Ohio in 1992. The motivation was not to be environmentally friendly or even to save money, but for the sake of silence. “I spend a lot of time outdoors. I love to garden, and here I’m listening to this conventional system all of the time making noise,” explained Bradley. “I hated the noise!” So different means of heating and cooling his home were researched and it was discovered that a geothermal system would solve the noise problem.
Geothermal heating and cooling systems take advantage of the ground’s constant temperature 365 days a year. But instead of digging trenches or boring straight down with wells, Bradley used a quarter-acre pond as the “heat sink,” utilizing water’s superior method of heat transfer. Pipe was installed on the bottom of the pond, with a combination of water and propylene glycol filling the piping. A compressor converts Puron®—the refrigerant—from liquid to a gas and vice versa, depending upon if it’s appropriate to heat or cool the space.
It is the earth’s constant temperature that saves energy, as opposed to directly raising or lowering dramatically varying air temperatures. The process is not complicated and requires the same components of the heat pump—a condenser, evaporator, compressor and blower.
Not surprisingly, given his distaste for noise, Bradley’s business has everything to do with sound. He spent 25 years making a living as a recording engineer, and falling in love with the sound quality of vacuum tube microphones. Today he repairs and sells those microphones to studios and musicians all over the world; a product he believes is superior to modern transistor types. Bradley moved from Ohio to Williamson County in 1996, because he loved the Middle Tennessee landscape. It’s a location that provides Bradley with ideal environments for both business and daily living.
When he built his custom home on Waddell Hollow, there was no question what type of heating and cooling system he planned to install. Bradley chose to sink two geothermal wells, each approximately 150 feet deep and fifteen feet apart, creating a closed loop system. In this system the anti-freeze solution is pumped through loops, and then through a heat exchanger with the refrigerant. He chose this method instead of a heat sink like he had in Ohio, because his present pond is too far away from the house. The prevalence of limestone in Middle Tennessee lends to an excellent medium for geothermal when digging wells for the heat sink.
Bradley’s home has three floors, including the basement. “Each floor has its own duct system, cold air return and thermostat. I can shut off any system in the house that is not being used. The water furnace system drives these three floors independently of each other. Now you don’t have to have geothermal to do the zone thing, but it feels like a winning situation when you know the earth is involved and your costs are down,” explained Bradley. He estimates that his savings per month exceeds $100. The entire system cost in the $20,000 range, “with all of the bells and whistles.” This is twice the amount of a standard heat pump, but geothermal will pay for itself in six to seven years.
According to Bradley, “There is very little maintenance on the system. I also used flex pipe for the air ducts, which adds to the quietness factor. Geothermal is a great idea. Its time has distinctly come, and if you deal with people who know it, and know the system well, they will do you well.”
According to the E.P.A., geothermal heat pumps are the most energy efficient, environmentally clean and cost effective systems for temperature control. The Federal government is now subsidizing the cost of geothermal installations to the tune of a 30 percent tax credit of the total cost, with no upper limit for existing or new home construction through 2016. The earth provides in amazing ways.
Williamson County resident Stuart Moore lives in the Fernvale Community and is a landscaper, writer and advocate for planet-friendly lifestyles.