TALLAHASSEE, FLA. — Florida State University is home to one of 14 off-grid zero emissions buildings (OGZEB) in the U.S. Developed by students and faculty of the university's Sustainable Energy Science and Engineering Center (SESEC), the building, located here on the University's main campus, was completed this summer and is registered to receive U.S. Green Building Council LEED Platinum certification.
The OGZEB is completely off grid — the house produces electricity from the 30 photovoltaic panels by SunPower and three AET water heating solar panels on the roof. During the day, the house runs off of the solar power, including the geothermal system and water heater. The water heater is a two-stage system; the sun heats up the water directly from the three AET solar panels first, then a hydrogen on-demand water heater is used if necessary.
“Part of the photovoltaic system is a 7,000 Watt inverter inside the building and SunPower pv modules generate electricity directly from the sun,” said David Smith, president of Sun Works, Jacksonville, Fla., installer and designer of the OGZEB's photovoltaic system. “They asked us for the best system available, meaning the highest efficiency, so we were able to specify the right inverter and sun power modules.
The geothermal system — an Envision system by WaterFurnace — was installed by The Earth Comfort Co., Savannah, Ga. The vertical geothermal loops have approximately 600 lineal feet of borehole, totaling 1,200-ft. of ¾-in. piping.
“Because they wanted to be off grid and have solar to power the house, the geothermal system uses less kilowatts to run the compressor and fan since it's a two-speed unit,” said Charles David, president and owner of Earth Comfort Co.
Any excess electricity not used in the house is stored in a hydrogen battery, a hydrogen storage system developed by SESEC, for use during the night. Tanks store up to 425 cubic meters of hydrogen that can be stored for 30 days. Not only is hydrogen used for power at night, it is also used to create power when not enough electricity is being produced by the solar panels, such on cloudy days.
“The hydrogen system is specifically a storage system in which excess electricity from the solar panels is used to split the water molecule into hydrogen and oxygen,” said Justin Kramer, research engineer with FSU's Energy and Sustainability Center. “The hydrogen is stored for rainy days and night time when the sun is unavailable. At night when electricity is required, the hydrogen is recombined with oxygen in a fuel cell and electricity is made.”
According to Kramer, when heating appliances like the stove, stored hydrogen will be combusted to create heat. The combustion technology was researched and developed at the University to find the parameters necessary to use it safely and efficiently. Also, the SESEC will most likely conduct tests and further research to develop new hydrogen technologies.
The OGZEB was built to research sustainable and alternative energy systems and technologies. Graduate students will live in the house for a semester or year at a time to test the sustainable technologies and their impact on energy consumption, air quality, humidity and temperature in the house.
“The house will be used to collect data on new sustainable and alternative energy technologies,” explained Kramer. “The house is designed such that it can be taken apart and put back together when new technologies are developed, so we can compare them to current technologies and develop methods to increase their efficiency, reliability and effectiveness.”
To conserve water, low-flow fixtures and a dual flush toilet have been installed, and the graywater system will be installed in phase two of the project after initial research data is taken.
“This is a research and development test bed for sustainable off-grid technology,” added Smith. “This is something that's not static; they are changing it and doing different things. We are excited FSU is really pursuing solar energy in a way that we have believed in for a long time. The research into sustainable technologies in the long run will benefit all of us.”
Additional information is available at: http://esc.fsu.edu/ogzeb.html.