Off-Grid Renewable Energy Student Design Project as Means ... · performed laboratory experiment...

Session ETD 375

Proceedings of the 2014 Conference for Industry and Education Collaboration Copyright ©2014, American Society for Engineering Education

Off-Grid Renewable Energy Student Design Project as Means of Hands-On Renewable Energy Education

Elena V. Brewer, Anthony P. Dalessio, Richard J. Hill

Erie Community College Abstract The Electrical Engineering Technology (EET) department at Erie Community College (ECC) currently offers a course in Photovoltaic Systems that provides students with a solid background in the design and operation of photovoltaic (PV) modules, inverters, batteries, charge controllers and balance of system components (BOS). As a part of the course, students perform sizing calculations and system design for a hypothetical PV system. In Spring 2013, the department took it one step further by offering students a real life renewable energy design project. This design project provides students with experience in sizing, designing and installing a renewable energy system for the college’s overhead construction and climbing facility. Students had to perform the following steps during the design stage: load analysis; site analysis; shading analysis using two different techniques; sizing calculations for the hybrid PV-wind system with battery backup that included temperature and rate of charge/discharge effects on the different system components; and financial considerations to keep the project within the allocated budget. The project was supported by a mini-grant from the ASEE's Engineering Technology Division (ETD) with 50% matching cost from the college. Students had access to various PV/wind system components already acquired by the EET department together with the additional funding from the ASEE-ETD mini-grant. Several student design groups were competing for the best project design with the intention of the best project to be installed at the site. The design projects were presented by the students to a panel of faculty and representatives from the local renewable energy industry. After the system installation, students will be able to document their work on the project for future industry certifications from organizations such as the North American Board of Certified Energy Practitioners (NABCEP) and the Interstate Renewable Energy Council (IREC). In addition to generating power for our off-grid overhead construction and climbing facility, PV and wind data generated by the installed system will be used by other departments in various ECC course offerings. Introduction The historic debate about what is the best and most effective way of teaching the student population is now as robust as ever. In the field of technologies, the hands-on or practical application approach is by far the leading effort in making education more effective1,2. It has been known for a long time that the best way of learning is by “doing it” yourself. That is one of the reasons Electrical Engineering Technology (EET) department at Erie Community College (ECC) is trying to actively incorporate such approach into various courses within the program.

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In 2011, the EET department introduced a new course in Photovoltaic Systems (PV Systems) EL 264 into the curriculum. The PV Systems course was designed in such a way as to balance the following required competencies: “sufficient theoretical background in PV modules operation and battery operation; overview of electronics in charge controllers, inverters and other components, necessary for understanding their behavior under various weather and load conditions; understanding and ability to perform load analysis, site survey, and shading analysis; ability to perform sizing analysis of modules, inverters, charge controllers and Balance-of-System (BOS) components to complete the PV system design in accordance with National Electrical Code (NEC) requirements; familiarization with wind load and other structural analysis techniques; and an ability to conduct economic analysis of the PV system” 3. The only feasible way to allow students to internalize this complex and comprehensive spread of information was to apply the knowledge acquired in the course towards the design project. The final team project included application of all learned steps and techniques to design a viable PV System. The deliverables of this team project were final project report and 15-20 minute PowerPoint presentation3. The design project course component was definitely a success allowing students to apply learned skills and techniques towards development of a viable PV system. However, the feedback from this project indicated that it would be even more valuable experience if students designed and implemented the real-life PV system. So in Spring of 2013, the department took it one step further by offering students a real life renewable energy design project. In Spring of 2013, the EET department had a unique situation where most of the second-year students were taking the PV Systems course and a newly developed Wind Power (EL 268) course at the same time which allowed them to learn photovoltaic and wind power generation and systems concurrently. The Wind Power course provided students with basic knowledge and skills on conducting wind turbine site analysis, wind resource analysis, wind turbine power/energy output, and mechanical and electrical components of the wind power system. This background gave students enough expertise to be able to incorporate a wind turbine into the renewable energy system in addition to the photovoltaic component. Therefore, the next logical step was to offer students a choice of designing the renewable energy system that is either PV or hybrid PV/wind system. Need for the Real Life Off-Grid Power System The EET department presently offers a certificate in Energy Utility Technology (EUT) for potential overhead electric line workers. The department runs an overhead construction and climbing facility during summers at the ECC south campus for this program. The facility is utilized for the climbing school for three to six weeks each summer, 40 hours per week. Since the climbing school is conducted outdoors with no access to electrical power, there is a definite need for an off-grid power system to power lights, power tools and additional appliances at the site4. The EET department was considering the possibility of installing the small renewable energy system to provide power for the climbing school. A 12V 350W wind turbine was installed at south campus during summer 2012 climbing school (Fig. 1). The department was going to complete the stand-alone wind/PV system for data acquisition purposes (for PV Systems, Wind Power and Renewable Energy in Electric Power Systems courses) and to run lights in the trailer for the climbing school. However, budgetary issues prevented us from completing this project in 2012.

Session ETD 375


Figure 1. Superwind 350 Turbine Installation

Student Design Project In the Fall of 2012, ASEE ETD division announced the competition for mini-grants (up to $5,000) for partial funding on projects which would benefit ETD or a segment of the engineering technology community. ETD gave as much latitude as possible to ETD members in the choice of projects. The project could focus on a single discipline and/or be of use to a particular college or system, so long as the results would benefit the larger ETD community. It was an excellent opportunity to finance the completion of the project the department was working on. EET department applied and won one of three mini-grants awarded. The mini-grant was allocated for the off-grid renewable energy student design project. It provided up to $5,000 towards the project assuming that at least 50% of the total project cost is matched by the college. The EET department’s matching contribution was over 50% and included the following: $2,500 Superwind 350 24V or 12V wind turbine with wind charge regulator and dump load; assortment of PV charge controllers ($400 - $1,500), eight 140W solar panels; 10 available absorbed glass mat (AGM) 105 Ah batteries; up to $1,000 from EET department budget; and installation of the utility pole ($1,400) plus pole cost ($600). The abovementioned equipment was made available to the students by the EET department with an understanding that students could choose some/all of this equipment or could specify different equipment altogether if it better fits their system design. The students were given the list of “customer” requirements specified by the summer climbing school

Session ETD 375


instructors and the EET department. System requirements included the following:

• 20A 120V AC circuit to provide lighting, charging capabilities for power tools, and power for small appliances such as portable ice maker inside the 40 ft. trailer (Figure 2),

• capability to power small monitoring/data logging system with the wireless access point for remote access of the collected data,

• low maintenance, sealed lead acid batteries (either AGM or gelled electrolyte) due to impossibility of conducting maintenance during winter months (the project site does not receive plowing services during winter),

• low voltage drops in the wiring since the system could be mounted up to 40 ft. high and 30-40 ft. away from the storage trailer where lighting was required (Figure 3).

Figure 2. Project Site – Storage Trailer Figure 3. Project Site – Outside View

The project site has fairly good wind resource throughout the year. Since there was no wind data available directly from the project site, data for average wind speeds was obtained from the National Weather Service located near the Buffalo International airport and used to determine Rayleigh wind speed distribution and projected turbine generated energy output. Students estimated that the average daily energy output from the Superwind 350 (24V, 350W) turbine should be at least 1KWh/day. The shading analysis, performed with the Solar Pathfinder, indicated that the PV panels will not have

Session ETD 375


any shading issues from 10:00AM until sunset throughout the year. Four groups of students performed laboratory experiment for shading analysis and tested numerous possible PV array/panel locations such as pole mounted, ground mounted on the south end of the trailer, mounted on the roof of the trailer, etc. Figure 4 demonstrates the shading pattern on the ground next to the outer most south pole. The only possible detriment to the PV array/panel production is the heavy snow during months of January through March which would decrease the power production from the PV array/panel. At this point, EET department left it to students’ discretion to decide how many PV panels they can use in the PV array. Another important aspect for consideration was the cold temperatures during winter in the Buffalo, NY area. The average low winter temperature is -8C with the record low temperature of – 29 C. This factor will substantially decrease the performance of the batteries during winter and will result in the somewhat oversized battery bank to sustain the operation of the project system.

Figure 4. Shading Analysis with Solar Pathfinder

Several student groups (2-3 students each) competed for the best design of the system within current specifications (energy audit, wind resource analysis, shading analysis, customer load requirements, customer system requirements, budgetary constraints, already existing equipment, NEC requirements, etc.) during Spring 2013 semester. This design competition provided students with real life experience designing actual renewable energy system. As was mentioned before, the combination of PV Systems course and Wind Power course (both are technical electives) provided students with unique background for possible design of the hybrid PV-Wind system. The deliverable for the design of the viable PV/Wind/hybrid stand alone system with battery bank was a PowerPoint presentation in front of judging panel with the portfolio of supporting materials (wind resource and shading analysis, load specs, major system components specs, array and battery bank sizing calculations, wire sizing calculations, etc.) provided at the time of presentation. The competition judging panel consisted of PV/wind industry representatives, customers (instructor from National Grid teaching the overhead construction and climbing course), ECC EET faculty and technical staff. Students presented four group design projects which ranged from systems utilizing only PV array to hybrid systems with wind turbine and PV panels. The winning project was determined based on judging panel scores and completeness of students’ portfolio. The course grade for the student design

Session ETD 375


project was determined based on judging panel scores, portfolio with system specification, presentations performance, and student peer- and self-evaluation.

The following judging criteria were utilized during competition and evaluated on the scale of 1 to 10: load analysis, minimum load requirements, space requirements, shading analysis, available wind energy analysis (if applicable), sizing calculations (PV array/wind turbine, charge controller, battery bank, inverter, balance of system components), identification of vendors and pricing, project budget considerations, completeness of specs for all system components, completeness of the project, and room for expansion. In addition to these technical criteria, presentation criteria were used for evaluation: eye contact, team work, appropriate use of PowerPoint, technical content, timing, elocution and appropriate audio level. In the process of assigning the grade towards the course for the team project, peer evaluation and self-evaluation were also included. Peer evaluations covered the following: clarity in definition and execution of roles within the team; following schedule for timely completion; group consensus, negotiation and compromise; equitable participation of all team members; flexibility to changing requirements and shared responsibility for success and failure. Self-evaluations included behavior rubric, organization rubric, and time management rubric. The winning project was the stand-alone off-grid hybrid PV-wind system prepared by Mathew Hawley, Louis Schiumo, and Eric Sturm. The group estimated load requirements at 1,429 Wh/day during summer use of the system (during climbing school) with the following loads utilized: 4x High efficiency light bulbs inside conex box (LED 15W, 25,000hr lifespan), portable ice maker (Ice under 10 min), flood light – ECC sign, outlet in conex box for charging cell phones, inverter, and PM-100-D PentaMetric data-logging tool. For the spring/winter/fall months, the load requirements were estimated at 588 Wh/day. The critical design month analysis indicated that the month of December is going to be the critical design month. This means if the system can provide enough energy during critical design month, it should definitely be able to provide enough energy during the rest of the year. The proposed system configuration included 120W Solarland High Efficiency Multicrystalline panel at 28º tilt angle (to maximize summer PV output during largest load power consumption period), 24V SuperWind 350 Micro turbine, Samlex America PST-2000-24V inverter, CSR 24 Marine 40A 24V charge controller, and 8x 105Ah 12V AGM batteries. The simple pole mount design for the PV panel and the turbine was utilized4. The minimum power rating of the solar panel was determined to be 107W. Figure 5 shows the hybrid system layout. Student Project Implementation/Installation One of the main difficulties of the project was the coordination of various project stages. In order for students to come up with the competent system design, they needed to cover most of the topics in the PV Systems course. This resulted in scheduling the actual system design competition at the end of the Spring 2013 semester. The competition took place at the beginning of May of 2013. The equipment requirements were finalized within the following week. However, some of the aspects of the students’ winning project had to be modified due to the logistics of ordering equipment through the county purchasing system where equipment items must go out for bid unless they are ordered from a vendor on the State’s contract list. The college must adhere to the county purchasing policies and we did not have much control over this issue. The items affected by this were batteries, battery box, and enclosure box for the charge controller and inverter.

Session ETD 375


Figure 5. Student Circuit Diagram4

Figure 6. System Installation

With the equipment being ordered at the very end of the Spring 2013 semester, the same group of students who designed the system were not able to perform the system installation. By the time all equipment was delivered, the senior class of students already graduated from the college. However, the students were offered an opportunity to come and participate in the installation process voluntarily. On the other hand, students enrolled in the Electrical Utility Technology summer climbing school had a chance to do the installation on the pole for the main components of the

Session ETD 375


system. The last portion of the equipment (charge controller and battery bank) was installed by the EET department’s faculty and technical staff at the end of summer (Figure 6). The only plausible way to overcome the scheduling difficulties would be to run two courses in PV Systems (basic and advanced), but the way the EET curriculum is built, students are ready to take higher-level electives (such as PV Systems or Wind Power courses) during their fourth and last semester. So, there is not much flexibility in this matter and having different groups of students performing design and installation tasks might be just an unavoidable aspect of performing real-life design and installation projects. Conclusion The off-grid renewable energy student design project was an overall success. Students designed and presented several viable renewable systems, ranging from pure PV system to hybrid PV/wind systems. They did get exposed to the “real world” design project starting with communication with customers and ending with the presentation of the final project. The winning student design system was installed, with slight modifications, at the Energy Utility Technology climbing school at ECC’s south campus. The system was a simple pole mounted hybrid PV/wind system with battery bank, charge controller, and inverter. The system will be used by EET department during summer climbing school to power up conex box lights and small appliances. It will also be used by the department to power up small data acquisition system (monitoring PV power output, wind power output, and battery bank charging state) and a wireless access point year around. The data obtained from this system will be utilizes in three different courses run by the department: PV Systems, Wind Power, and Renewable Energy in Electric Power Systems. In addition, the data will be utilized in various courses from Environmental Science program as well as from other programs. Bibliography

1. John R. Mergendoller, Nan L.Maxwell, and Yolanda Bellisimo, The Effectiveness of Problem-based Instruction: A Comparative Study of Instructional Methods and Student Characteristics. The Interdisciplinary Journal of Problem-based Learning, 2006. 1 (2): p. 49-69.

2. David Gijbels, et al., Effects of Problem-Based Learning: A Meta-Analysis from the Angle of As- sessment. Review of Educational Research, 2005. 75 (1): p. 27-61.

3. Elena V. Brewer, Anthony P. Dalessio, “Effective Low-Budget Approach to Teaching Photovoltaic Systems to Electrical Engineering Technology Students at Community Colleges”, Proceedings of the ASEE 2012 National Conference – Energy Conversion and Conservation Division, 2012.

4. Elena V. Brewer “Real-Life Design Project Approach to Teaching Renewable Energy”, 2013 Sustainability Conference, Alfred State SUNY College of Technology 2013.

Biographical Information ELENA V. BREWER, PHD

Session ETD 375


Elena V. Brewer is a Chair of and Instructor at the Electrical Engineering Technology department at Erie Community College. She received her BS in Physics from Irkutsk State University in Russia and her PhD in Physics from the State University of New York at Buffalo. Her current interests include renewable energies in general and photovoltaic systems in particular, nanotechnology, physics, electrical circuits, PLCs and automation. ANTHONY P. DALESSIO Anthony P. Dalessio is an Assistant Professor of Electrical Engineering Technology at Erie Community College. He received his BS and MS in Electrical Engineering from the State University of New York at Buffalo. His teaching interests include analog and digital electronics, RF circuits and systems, renewable energy, and semiconductor fabrication. RICHARD J. HILL Richard J. Hill is a Master Electronic Technician and Assistant Professor PT of the Electrical Engineering Technology at Erie community College. He received his AAS in Electrical Engineering Technology from Alfred State College. His interests include photovoltaic systems, wind power, nanotechnology and electronics fabrication. On more personal note, his hobby is getting friends and family out of technical mishaps created by new technology.

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Off-Grid Renewable Energy Student Design Project as Means of Hands-On

Renewable Energy Education

Dr. Elena V. Brewer, Anthony P. Dalessio, Richard J. Hill

Erie Community College

2014 ASEE/CIEC Conference, Savannah, GA, February 5, 2014

Final Budget Breakdown


Equipment and installation ECC‐match

Utility pole and installation $2,000

Superwind 350 24V wind turbine with SCR 24 Marine charge controller

$2,500

Power Bright 24V 400W inverter $ 36

Wind Turbine mount $ 238

Steel NEMA 3 Enclosure 24X20x8” $ 254

Steel NEMA 3 Enclosure 8X8x4” with distribution block $ 53

24V to 12V, 3.8A DC to DC Converter $ 5

Bogart Pentametric Monitoring System (system input, monitor display unit and ethernet interface)

$ 413

Miscellaneous (wire, conduit, brackets, hardware and mounting structure)

$ 650

TOTAL $6,149

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Equipment and installation ECC‐match Grant‐financed

Ground Fault Protector and Rail Mount Breakers $ 98

100A / 100mV DC Shunt $ 54

4 245‐AH Sealed AGM Batteries, 12 VDC $1,671

Battery Terminal Adaptors, Cable Assembly, etc. $ 326

NEMA 3R Aluminum Battery Enclosure, 16x48x24”

$1,085

120W 24V Multicrystalline Solar Panel, Solarland $ 227

Conference presentation $ 800

Delivery charges $ 739

TOTAL: $5,000



ECC‐match Grant‐financed

$6,149 $5,000

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Conclusions

• Designed hybrid system met most load requirements and specified system requirements

• The system (with minimum modifications) was installed within the budget constraints

• Students received valuable experience designing real‐life hybrid stand‐alone system

• EET and EUT students gained hands‐on experience during installation of the system


Conclusions

• The installed system will be utilized to power lights, ice maker, and other small loads during summer climbing school

• The rest of the year, the system will provide power for monitoring/ data collection system allowing us to collect data pertinent to solar and wind power production at the site. EET department has plans of offering this site as a testing site for various small turbines in the future.


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Conclusions

• Generated data can also be used in the various courses related to renewable energy generation, for example PV Systems course offered in Spring 2014.

• System was already utilized for the Environmental science course during Fall 2013.


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