Sierra Club’s Geothermal Net-Zero Building — 4 Years Later

St. Petersburg, Fla., got its first net zero energy, fully self-sustaining commercial office building almost four years ago, in December 2012. Like so many other energy independent buildings, the path was fundamentally simple; reduce energy consumption as low as possible, make up the rest with solar PV power.

Pictured above, the building has four tenants and is set up like a classic strip-mall. The Sierra Club’s Florida headquarters fills the West end as the anchor tenant. When the building opened for business in 2012, there was a lot of publicity, but there’s really not been so much talk about it since then.

Over the past few years, I’ve visited the building a few times, always stopping in to visit the folks at the Sierra Club. Late in July 2016, I was entertaining an official from the Philippines on business; he’d asked to see some geothermal cooling sites in Central Florida. At one of our four stops that day, we visited the Sierra Club.

Frank Jackalone, Sierra Club’s Florida Senior Organizing Manager said that he’s very pleased with his almost-four-year-old accommodations. Frank willingly shared his experiences and thoughts on the building’s operation and how everything has been going.

Geothermal heat pump with exposed spiral seam ductwork

I asked Frank how well the building has been operating in a “Net Zero” capacity, knowing full well that cooling hours in Central Florida are high. Frank said the landlord reported to him that the building has produced 40 percent more energy than it has consumed. He noted that the building is fully occupied (Sierra Club is the anchor tenant; but there are three other lessees in the center).

When asked how the geothermal system is performing, he said the he is “…extremely happy…” with the system’s performance and the comfort level of the air conditioning.

Since the building has all electric geothermal heating, cooling and hot water, in addition to the normal complement of office equipment, I asked what he is charged for electric — thinking the landlord must charge them for maintenance or convenience fees. Frank told us that the Sierra Club has no electricity charges or fees at all. What a remarkable concept; all that comfort and dependability, no outdoor equipment noise or clutter, and no electric bill; truly Net Zero. And with no combustion heating, it’s likely close to Net-Zero emissions. By the way, Frank does drive an electric car, and, you guessed it, he fills up for free each day at work.

Electric Car Charging Station

When asked his recommendation to anyone desiring to go Net Zero, Frank cited three steps to follow.

“First, design the building envelope tight and well insulated,” he said. “Second, put in geothermal cooling and heating. Third, put in enough solar energy to cover the rest.”

A geothermal heat pump (GHP) is able to work effectively with fluid temperatures between 25F and 110F. When the GHP needs to heat, it extracts BTUs from the source (the earth). When it needs to cool something, it rejects BTUs back into the source.

Think about the temperature outside when air-conditioning is normally needed. Chances are that the outside temperature during the cooling season will be 80F, 90F or warmer. The 40F-70F earth is an excellent heat sink, providing energy efficiency that is far superior to any other cooling system.

Illustration Credit: Pixy Jack Press

The same principal works in the heating mode. Whether it’s 60F, or zero, the earth has loads of energy to supply the GHP, and the efficiency rating is superior to anything else available.

Sierra Club’s Florida headquarters are located at 1990 Central Avenue in Saint Petersburg, and the building is listed on the Department of Energy’s (DOE’s) Building Data Base. Next time you’re in Florida visiting, or if you’re on vacation, stop in, get a charge for your electric car, and tell the folks at Sierra Club that Jay sent you.

Special Thanks to PixyJackPress and Donal Blaise Lloyd for use of illustrations from the book, Geo Power.

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