Last week I told you about Freedom Field Renewable Energy - a living laboratory. One of the great things about FFRE is its partnership with regional institutions of higher learning. Since the facility went live in 2010, dozens of students have performed internships and completed interdisciplinary capstone projects that provide hands-on experience to help them gain practical workforce skills. And the relationship works both ways; student projects help Freedom Field serve as a proving ground for advanced renewable energy technology. Here are a few examples of the work that students have done at Freedom Field.
Solar Assisted Electric Vehicles
One student in Rock Valley College's Sustainable Energy Systems (SES) program had a gasoline-powered go-cart, which he decided to convert into a solar-assisted electric vehicle (SAEV). He recruited two more students - one in Electronic Engineering Technology and another in Manufacturing Engineering Technology - to collaborate on the retrofit. The project would satisfy the students' capstone course requirement.
The trio stripped the vehicle down to the barest essentials in order to decrease its weight. They outfitted it with a series-wound DC motor which, when geared down, delivers plenty of low-end torque, and powered it with a pair of deep cycle lead-acid batteries. A 220 watt Universal Solar PV panel charges the battery and doubles as the car's roof. The SAEV can also be plugged into an AC outlet to charge the batteries when adequate sunlight is not available. The students added a charge controller, some pretty cool LED lighting, turn signals, and miscellaneous electronics to complete the job. Check out their video which shows the assembly process and the car in action.
SAEV1 converted a gasoline-powered go-cart into an EV. While the vehicle performed reasonably well, its frame was still a bit too heavy. A few years later, two students in RVC's Manufacturing Engineering Technology program decided to design and fabricate a new frame from scratch. They chose aluminum for its high strength-to-weight ratio and because it's a recyclable material.
SAEV2 uses a 36V DC motor, which requires three batteries. The motor connects to a chain drive to convert motor speed into torque. Like SAEV1, the solar panel and charge controller charge the batteries, and an AC adapter provides an alternate charging source.
Solar Photovoltaic Testing
In order to test various solar panel mounting configurations, Freedom Field supported three different projects, each consisting of four 220 watt PV panels. One team of students designed and built a fixed mount that faces due south. The array's tilt is adjustable so it can be optimized for the season. It's tilted at 43 degrees (the site latitude) during spring and fall, 58 degrees to capture the low winter sun, and 28 degrees for optimal summer performance. (Side note: one of the students was thrilled that he was able to apply his newly-acquired trigonometry knowledge in the design of this PV mounting bracket. Pay attention in math class, kids!)
Another team of students designed and assembled a similar mount, but faced the panels 20 degrees west of due south to capture more afternoon sun. Although panels facing due south will deliver the most energy overall, aiming the panels a bit west will capture more sunlight in the mid-to-late afternoon, when people are using more power. A solar array that faces southwest will provide more power during peak demand hours, which could be of greater value as utilities switch to time-of-use pricing schemes.
A third group wanted to experiment with a PV mount that tracks the sun during its daily east-to-west trek across the sky, but rather than using an electric motor with an electronic control system, they found a passive solar tracking device. The tracker consists of a tube filled with a fluid that boils as it gets heated by sunlight. This shifts the weight distribution of the tube, which, in turn, moves the panel. After taking data for over a year, students found that the system works very well in warm weather but not so well in the winter, making it more suitable for southern US locations.
You can see the data for these projects at FFRE's data page.
Inverter Test Stand
Danfoss is a local manufacturer of PV inverters and variable speed drives. Rock Valley College's multidisciplinary capstone course often matches students with local companies that have a project in mind but don't have the enough personnel to do it. In this case, Danfoss partnered with Freedom Field and RVC to develop an inverter test stand and a detailed safety and testing procedure. Students built the test stand, created the testing procedure (under the guidance of RVC professor Steve Fleeman), and wrote two manuals for technicians who will be using the stand.
Lighting Display Tent
LED bulbs are more efficient and longer-lasting than incandescent or fluorescent lights, and Freedom Field's executive director, Chet Kolodziej, wanted a testing and demonstration center to show various LED light bulbs. Two student interns spent a summer evaluating different bulbs for heat, light, and power consumption. FFRE purchased a tent, the lights, a lux meter, and identical light fixtures, as well as several WeMo smart outlets. The WeMos allow the bulbs to be controlled remotely and they keep track of how much total energy each bulb has used over a period of time. Visitors touring Freedom Field can walk through the tent and see several informational posters about lighting.
The tent also has a webcam for remote viewing. FFRE purchased an iPad on which a student intern installed and configured the WeMo and webcam apps. The iPad is now at Rock Valley College, where students in Sustainable Energy Systems classes can remotely operate and monitor the lighting tent.
ARoMA
Freedom Field is located near the Rock River Water Reclamation District, and on certain days … well, let's just say that you can tell that there's a sewage treatment plant nearby. Two electronic engineering technology student interns working at FFRE over the summer decided that the ventilation system should work harder when the air is unpleasantly aromatic. The students researched malodorous chemicals and found sensors that detect and measure those substances. They placed the sensors in various locations around the facility and set them up to transmit their data using the XBEE wireless protocol. They designed a control circuit that reads the sensor output and, based on the chemical composition of the air, adjusts the variable frequency drive that runs the fan motor.
The students dubbed their creation the "Automatic Removal of Miasmic Air" (ARoMA). You can read their technical report here.
Rock Valley College Water Quality Monitor
Freedom Field doesn't just support engineering and technology. The Rock Valley College campus is bisected by a creek that doubles as an outdoor biology lab. The college club Students for Responsible Environmental Sustainability (SRES) requested support from FFRE to design and install a water quality monitoring system in the creek. An array of sensors is powered by a battery that's charged by a small solar panel. The system transmits data over a cellular link, and the data is displayed on a public web page. Biology students are trained to collect and interpret data from the system.
The creek monitor was an interdisciplinary project - biology students listed the requirements, electronic engineering technology students specified the sensors, and sustainable energy systems students designed the solar battery charging system. Beyond academics, the college's Plant Operations and Maintenance department handled the logistics and oversaw the installation. Freedom Field Renewable Energy purchased the hardware and software.
Rock Valley College Multi-Purpose Solar Powered Station
Inspired by the US Environmental Protection Agency's Village Green project, RVC's environmental science students requested a multi-purpose weather station on campus. This interdisciplinary project included students in environmental science, sustainable energy systems, and building construction management, as well as RVC's Plant Operations and Maintenance department. The weather station was sponsored by Freedom Field, who used the proceeds from the 2015 Northern Illinois Renewable Energy Summit & Expo to fund the project.
The weather station is entirely off-grid, powered by a battery bank that's charged by a solar panel. It measures temperature, wind speed, barometric pressure, humidity, dew point, and precipitation. Data is sent to a server via a cellular link and is accessible through a public web page. Between the two seats, you can see the battery bank housing, which includes a pair of USB charging ports, so students can relax by the creek and charge their phones.
The original design called for a multitude of air quality sensors but that turned out to be too costly, so he students left room for additional sensors, making this a base for future capstone projects.
That's a tiny sample of the many activities that students have performed through the partnership between Rock Valley College and Freedom Field Renewable Energy. Collaborations among business, government, and academia provide opportunities for students to learn professional skills while attending college. At the same time, the students deliver valuable products and services to the region. A community is stronger when its agencies work together!
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