By CRAIG R. CLARK, P.E., and DAVE KOSTICK August 28, 2013
The Wellsville campus of Alfred State College in New York’s Southern Tier is known for its “learning by doing” trade programs. With most of the pro- grams focused on real-world work, such as building homes for sale, the school is one of the largest workforce providers for the state’s construction industry. So, during the past decade, as local businesses have asked for students with green technology skills, it was natural for us to deliver that training through hands-on experience.
The construction-related programs have been building and selling homes in Wellsville since 1966, homes built entirely by students through their laboratory coursework. Through a 2007 grant from the Appalachian Regional Commission (ARC), we took this program one step further: We would build a zero-energy demonstration home on campus to serve as a learning laboratory for students and the community. It would use sustainable building materials and techniques and be powered by photovoltaic (PV), solar thermal, geothermal and small wind systems. A monitoring and control system would generate real-time data for students to analyze and for displaying to the public.
Construction took place from August 2009 through May 2011, with the monitoring system installed that December. Last year the house earned National Association of Home Builders (NAHB) Gold Certification, the Association for the Advancement of Sustainability in Higher Education’s Best Campus Sustainability Award and the Siemens Application of the Year Award. Most importantly, the experience our graduates have gained through this project has helped them launch careers in sustainable building and renewable energy.
Going for Green Building Gold
Alfred State College is part of the State University of New York system, and its programs directly link to workforce development. Graduates typically have a 98 percent placement and transfer rate each year. Alfred State’s campus in Alfred, N.Y., houses the traditional two and four-year college programs. The Wellsville campus houses the skilled trades programs: building construction, electrical, automotive, culinary arts and computerized design and manufacturing. For the 800 students in these programs, a typical day will include 1.5 hours of lecture and 4.5 hours of laboratory. Labs might involve repairing vehicles in the auto shops or serving prepared food for customers.
Over the past 10 years, all five programs have integrated green technology into the course work, based on industry requests. In the construction-related programs in Wellsville, this integration was made possible through grants. Beginning in 2003, our focus on renewable energy began with a New York State Energy Research and Development Authority (NYSERDA) grant to train PV installers.
It was followed by a 2007 Appalachian Regional Commission grant to further develop the ability to teach PV systems and begin teaching the installation of small wind systems. In 2009, ARC funded grants to develop weatherization training and a green building laboratory. That same year, NYSERDA also award- ed a $2.2 million Clean Energy Training grant, to develop educational modules in geothermal, solar thermal, small wind and photovoltaic systems in a consortium of colleges led by Alfred State. The green home laboratory integrated all of this knowledge in a net-zero-energy demonstration home.
We had three goals for the home:
- To give students real-world experience with renewable energy technology and green construction techniques;
- To showcase the high-quality student work and demonstrate to the public that a typical-looking home can be built sustainably; and
- To provide a living laboratory for educating the future workforce in green building techniques.
This vision was funded by the ARC with a start date of April 2009. During the preparation year for the project, faculty selected a home layout and materials for most components. That included working with regional suppliers of appropriate green materials and discussions with the local and state NAHB organizations. The college decided to work toward a minimum goal of NAHB Gold certification. As it turned out, the biggest challenge of the entire project was following the NAHB standards, including collecting and weighing all materials to be recycled.
We selected a one-story home design, in order to assure accessibility for all visitors, regardless of mobility. The home is approximately 2,200 square feet (200 square meters) with three bedrooms, including a master bedroom suite with master bath and walk-in closets. Both the entryway/family room and master bedroom have cathedral ceilings. The house has a full dining room, den and kitchen with an eat-in breakfast area. There are two additional full bathrooms and a workshop, as well as a fireplace and an attached garage.
Since the home was to be a showcase home, we made some minor modifications to the layout. The master bedroom’s walk-in closet was modified to be a handicapped restroom and a storage closet for the laboratory. The workshop was modified to be the mechanical room so that all visitors could assess the mechanical space. The dining room and den are used for office space, and the master bedroom is used as a conference room. Many of the renewable energy components are installed in the garage.
We selected most of the materials, systems and construction techniques for their green attributes and because they were technologies we wanted to have the students install. Since all operations were to be on the ground floor, we eliminated the basement (a normal feature for homes in the area). We used a frost-protected shallow footer system, with footers capable of being located only 18 inches below grade — above the frost line. The protection includes placing insulation horizontal to the footings to prevent frost penetration.
We also installed a form-a-drain system, a hollow plastic material used to form the concrete footings. Form-a-drain is left in place to act as a drainage system and can also be used to vent the system from any radon in the soil.
Since there was to be a conditioned crawl space in the house for utilities, we used insulated concrete forms with an R-value of 17. The floor system was standard engineering I-joists and was built to tight tolerance since the wall system we selected was of structural insulated panels; their R-value is 24.3, at 40°F (4°C). Since most students will be installing trusses in their future jobs, we selected a truss system for the home. The roof system was very complicated due to the cathedral areas, and we found only one company in the area that could build the trusses.
All during the requisition of materials, we worked with local suppliers to obtain the appropriate green materials and certifications required for the NAHAB certification. The internal walls were constructed of 2×4 wood framing and were sheet-rocked.
The high-efficiency windows have U-values of 0.25. The outside building envelope was wrapped and sealed, and all cracks, including windows, were sealed.
Because the home was to be green and airtight, all finishes were selected to be low – to no – volatility material, including the paints and the carpeting. The oak kitchen cabinets were custom-built by students in the building trades program and, again, used low – volatility finishes. Interior design students on the Alfred campus selected colors, tiles, carpeting and lighting fixtures.
Installing RE Systems
The original plan for the house included renewable energy, but with additional grants, we were able to expand the renewable energy systems.
Students installed an 8.8-kilowatt PV grid-tie system as two arrays, with two separate inverters to allow for better monitoring. The 2.5-kilo- watt Proven 7 small grid-tie wind turbine was installed prior to the home’s construction as part of another grant.
During the home construction, students installed a 2-ton geothermal system with four vertical closed-loop wells. Working with the well driller, we had four different grouts installed. Each grout had different thermal transmittance properties.
Thermocouples were installed to measure the temperatures to the full depth of the wells. An eight-vacuum-tube solar thermal system was installed with a storage tank. Another electric water heater was installed to act as both a surge tank and a primary heat source when solar energy is inadequate. We also installed a Temp-Cast wood-burning fireplace that is about 97 percent efficient, using radiant heat.
The geothermal heat pump and solar thermal tanks are both installed in the mechanical room.
The inverters for the wind turbine and PV panels are located in the garage.
An air-exchange system with heat recovery is also located in the mechanical room. The home was wired for phone and communication systems that all terminate into one control panel in the garage, as well.
This is something the students do in all homes we construct, but this is the first home that we completed with cable, telephone and internet being operational. Because our goal was net-zero-energy usage, all of the appliances installed in the home are electric. This will allow us to better monitor the energy usage.
Monitoring for By-the-Moment Performance
By fall of 2011, the home was essentially complete and operating. We planned to build and operate a monitoring system that would allow the college to showcase the operation of the home. We also wanted to be able to operate the home with full loads to show the public its net-zero-energy operation.
Late in the summer of 2011, Alfred State College was introduced to IMT Solar, a maker of solar test, measurement and monitoring equipment, and, through the NYSERDA grant, we designed and installed a system that fall.
The system was essentially an expanded version of IMT Solar’s REVTOS (Renewable Energy Visual Tableau Operations System) monitoring and control system. IMT Solar had never before installed monitoring for geothermal or solar thermal systems, but they knew their system had the scalability and flexibility to include these as well.
Upon inspection of the house site, IMT Solar decided to divide the monitoring system into two control cabinets: one placed in the mechanical room and the other placed in the garage. That saved an enormous amount of wire runs from the various sensors and power monitors utilized in each system. In addition to the dedicated touchscreens located in the front door of each control cabinet, IMT Solar also mounted a 23-inch touchscreen PC in the living room of the home.
All three screens have graphic displays to show both real-time and historical data from the four renewable energy platforms. Additionally, temperature sensors are located in the ceilings and walls in two locations, each to measure the temperature differential between the inside of the drywall and just below the surface of the insulation.
An outside temperature sensor in a radiation shield displays the outdoor temperature at all times. An iPad, supplied as part of the system, also allows us to show the graphical data as we give tours of the house.
IMT Solar installed power meters on each of the power production platforms (the two PV inverters and one wind inverter), on the major power consumers (the geothermal heat pump system, backup resistive heating unit, heat-recovery ventilator, solar thermal pumps and electric backup water heater), and on the main power distribution panel. That allows us to see exactly what is going on, electrically, within the entire house.
Sixteen temperature sensors installed during installation of the four geothermal wells are also tied into the monitoring system. Doing so allows us to study the thermal transfer characteristics of the four different grout systems. Built-in web servers in the IMT REVTOS system allow the monitoring screens to be brought into any classroom on campus. The same data can also be seen via our website.
Screen captures of the real-time data, as well as the historical data files (stored in Microsoft Excel file format), will allow us to study all aspects of the renewable energy systems in the home, today and into the future.
All of the energy systems are performing exactly as projected. We had a good idea of what to expect with the PV arrays, having installed a 5.1-kW system, with monitoring, on campus a few years ago. As of Jan. 1, 2013, a year after our monitoring system went online, our total grid usage for the house for the year was 13 kilowatt- hours — about as close to zero-energy as you can get. See real-time data at alfredstate.edu/sustainability/zero-energy-green-home.
The home continues to be a learning laboratory for our students, local high school students, the public and the contractors. We give tours regularly, including tours for perspective students to the college. In the summer, we offer a two-day training event for high school technology teachers. We are now involved in constructing a much larger demonstration home in Alfred that will house the college president and be used for community events.
Craig R. Clark (email@example.com) is executive director and dean of Alfred State College’s School of Applied Technology in Wellsville, where he oversees the college’s satellite campus with an annual budget of more than $3 million with 65 faculty and staff. Clark has been associated with Alfred State College since 1979, serving in a variety of teaching and administrative capacities, including professor and department chair, Civil Engineering Technology, as well as interim vice president for academic affairs. He also is in charge of the Center for Renewable Energy at the college.
Dave Kostick is currently involved in commercial technical sales at Solar Liberty. He was formerly the sales manager and engineering manager at IMT Solar. Prior to that, Kostick spent many years in the industrial automation field, which led him to develop the REVTOS system using very robust, off-the-shelf, industrial automation components.