For contractors and manufacturers in the geothermal segment of the HVAC industry, Zero-net-energy (ZNE) projects are becoming an increasingly popular way to save energy and showcase the green movement away from fossil fuels and carbon emissions.
The total amount of energy used by a ZNE site annually is the equivalent to (or near) the amount of renewable energy it creates.
“We are seeing new developments with the goal of net zero in numerous commercial projects,” said Doug Dougherty, president and CEO,Geothermal Exchange Organization (GEO). “The easiest way to a net-zero installation is a geothermal system. Those that are enlightened enough to try and achieve net zero typically always use geothermal.”
“Geothermal HVAC systems remove up to four times more kilowatts hours of consumption from the electrical grid per dollar spent than photovoltaic (PV) can add to the electrical grid per dollar spent,” said Jay Egg, president, Egg Geothermal, Port Richey, Florida. “Homes and businesses desiring a net-zero status come closer to making that a reality by first implementing geothermal HVAC technologies. When considering a net-zero application, this significantly reduces the size of the PV array and related costs.”
“ZNE was one of those things that was nice to think of, and you could sacrifice a ton to do it, but now you can reach these efficiencies without the sacrifice,” said Joe Parsons, COO of EarthLinked Technologies Inc.
Those efficiencies are quickly gaining momentum and becoming a reality, as ZNE commercial projects have been completed, or are currently underway, throughout the country.
Bullitt Center Building
The Bullitt Center office building in Seattle opened on Earth Day, April 22, 2013, and is owned by the Bullitt Foundation. The six-story, 50,000-square-foot Bullitt Center was designed to be one of the most energy-efficient buildings in the U.S., achieving an energy efficiency 83 percent better than the typical Seattle office building. In order to reach the goals of net-zero energy and water use, the Bullitt Center is equipped with a geothermal system, in-floor radiant heating, a canted and extended 14,000-square-foot rooftop with PV solar capture arrays to make electricity, a rainwater capture/purification system for potable systems with a 56,000-gallon basement cistern, on-site waste management, and thermally glazed curtain wall windows that open and close automatically in response to outside conditions to maximize daylight.
FHP Mfg. AP, CA, ES, EP, and WW Series heat pumps were specified by PAE Consulting Engineers comprising a total of 10 units. The conference rooms, elevator machine room, and data center all get their heating and cooling from the heat pumps. FHP water-to-water heat pumps are connected to Uponor PEX to deliver heated or chilled water for radiant heating or cooling, and to generate heat recovery for the ventilation system’s 100 percent outside air unit to precondition incoming fresh air with outgoing air. The vertical closed-loop geothermal system consists of 26 geothermal wells, each 400 feet deep.
According to Justin Stenkamp, mechanical engineer, PAE, the selection of the FHP products was made on the basis of their performance characteristics along with working relationships and a strong track record for service from FHP Bosch representatives on previous projects.
The building also aims for certification of the Living Building Challenge, a verification process consisting of 20 necessities that go beyond Leadership in Energy and Environmental Design (LEED) requirements.
“After seeing how the Bullitt Center performed in its first year, I’m certain we will be net positive energy, not just net zero,” said Denis Hayes, CEO of the Bullitt Foundation. “If we can do this in cloudy Seattle, owners in other cities should be embarrassed if they don’t achieve zero-net energy.”
Walgreens ZNE Retail Store
The Walgreens retail store located at 635 Chicago Ave. in Evanston, Illinois, opened in November 2013 and features a geothermal system, two wind turbines, and nearly 850 solar panels.
Mark Wagner, president of operations and community management, Walgreens, said, “This is the first time we are bringing all three of these technologies, along with many other technologies, together in one place. Our purpose, as a company, is to help people get, stay, and live well, and that includes making our planet more livable by conserving resources and reducing pollution.”
The store’s energy-efficient plans included drilling 550 feet underground and obtaining geothermal energy. The temperatures at that depth are more constant and allow for both heating and cooling of the store. However, there are many other green elements of the Walgreens, as the aforementioned turbines use wind from Lake Michigan to generate power and offset annual greenhouse gas emissions, and energy-efficient building materials were used in constructing the store. Green elements like an electric vehicle charging station and bike racks are also featured.
“We are investing in a net-zero energy store so we can bring what we learn to our other stores and share what we learn with other companies,” said Thomas Connolly, vice president of facilities development, Walgreens. “Because we operate more than 8,000 stores, anything we do to reduce our carbon footprint can have a broad, positive impact on the nation’s environment.”
Walgreens’ engineering estimates believe the store will use 200,000 kWh per year of electricity and generate 220,000 kWh, achieving the balance needed for ZNE.
The store is seeking platinum certification through the U.S. Green Building Council’s (USGBC’s) LEED program, Net Zero Certification through the Living Building Challenge, and it has received GreenChill platinum certification through the U.S. Environmental Protection Agency (EPA).
Lady Bird Johnson Middle School
Lady Bird Johnson Middle School in Irving, Texas, was among the first public schools in the U.S. to become ZNE.
The school features a variety of sustainable technologies, including FHP geothermal heat pump systems, to significantly reduce energy consumption. The installation includes 107 Bosch FHP model EV and EC geothermal water-source heat pumps fed from 505 geothermal wells bored approximately 250 feet deep.
The site also includes 2,988 solar PV panels with a 600-kW solar array and 850,000-kWh annual output, a wind turbine generating 2.4-kW electrical capacity, and light shelves and light harvesting for daylight in classrooms.
“LBJ middle school is the first school utilizing geothermal systems in the district, and the owner has been impressed with the geothermal system installed at this campus,” said Don Penn, engineer, Don Penn Consulting Engineer, Grapevine, Texas.
Jim Scrivner, accredited Texas energy manager, Irving Independent School District (IISD), said, in its first full year of operation, the school achieved more than 99 percent net zero. “When energy use is compared with other schools in the same district, LBJ Middle School consumes about 60 percent of average energy consumption.”
The school’s design was used as a means to motivate students and reduce energy use. Students are able to utilize an interactive monitoring center and take part in numerous class activities.