EE Students Complete Photovoltaic R&D for Industry in Electrical Engineering Curriculum

Rowan University is committed to providing undergraduate engineering students with experience in real world problems as part of its engineering curricula. Through the participation of Industrial Affiliates, we have been able to involve undergraduate students in a number of renewable energy research and design projects. This paper describes the structure and methodology of Rowan University’s Junior and Senior year clinic model as well as a specific clinic project that provides students with the experiential learning opportunity in which they can apply their engineering knowledge and resourcefulness to a real-world project. During the 2010-2011 academic year, Kaneka Corporation of Osaka, Japan sponsored the design, engineering, permitting and installation of a photovoltaic (PV) system test bed located at Rowan University’s Rowan Hall, utilizing Kaneka’s new multi-junction “Hybrid” amorphous modules. The installation required that all work be completed in accordance with local laws and codes as well as be designed for optimal array output. Working in an engineering clinic environment, modeled after the medical school approach, undergraduate engineering students were charged with design and installation of this system to meet any necessary political and design specifications. This involved every aspect of design, including obstruction shading analysis, PV array layout, single-line design, specification, procurement and purchasing of all required balance of system (BOS) equipment, as well as plan submittals for Rowan University and New Jersey Department of Community Affairs (DCA) approval. Through this engineering clinic model, students learned all the inner workings of how a grid-connected PV array goes from concept to reality, ending with a finished product for the client. Most importantly, the Rowan University clinic experience allowed students to effectively communicate with representatives of the sponsoring agency and report the findings of a semester long research, design and development project. Background The four Rowan University Engineering programs offer an inter-disciplinary Engineering Clinic program, which consists of an eight-semester sequence of courses that must be taken by all Engineering students [1]. Freshman students in Chemical Engineering (ChE), Civil and Environmental Engineering (CEE), Electrical and Computer Engineering (ECE), and Mechanical Engineering (ME) take a 2-credit hour clinic during the fall and spring semesters. At this level, the emphasis is on learning the process of engineering through measurements on exemplar engineering systems, and reverse engineering of typical appliances or processes to illustrate key engineering concepts [2]. Students are managed as a class with the composition of each class a mixture of all four disciplines. During the sophomore year, students take 4-credit hour clinics. In the fall, the general education Composition course is integrated with a design project. This emphasizes the importance of technical writing as an integral part of the engineering process. In the spring, the general education Public Speaking course is again integrated with a design project underscoring the importance of oral communication as a vital component of engineering. The final four semesters of Engineering Clinic are designed to provide junior and senior students with the opportunity to collaborate on real world projects for external clients or sponsors and to present solutions by applying multi-disciplinary engineering concepts. Each department sponsors approximately 8-15 projects and solicits students from each discipline as appropriate to the project. Students work in small teams usually consisting of 2-5 students. Their projects are typically sponsored by industry partners, government agencies, or can also be student-led, entrepreneurial efforts. Recent examples of sponsored projects within the Electrical & Computer Engineering department include: development of a statewide energy assurance plan, immersive virtual reality system for storm run-off modeling, algorithm development for early detection of Alzheimer’s, and a large number of projects focused on the evaluation, design, and implementation of photovoltaic (PV) systems. Example Clinic projects sponsored by other disciplines, such as the Civil & Environmental Engineering and Mechanical Engineering departments include aquifer recharge analysis, fatigue and fracture mechanics studies on recycled concrete aggregates, and development of an automatic energy harvesting kite. A typical Clinic project sequence includes: development of a clear and concise problem statement, background information search and review; design approach development, analysis and simulation, prototyping, testing, and presentation of results via written report and presentation [3]. There are Professional Engineers (PEs) on the faculty to provide the required supervision for those projects that require sealed drawings, etc. From the engineering curriculum standpoint Clinic projects provide an opportunity to develop many important skills that expand, reinforce, and complement the student’s educational experience. The junior and senior Clinic projects help students progress from basic problem solving techniques to the more advanced techniques needed to deliver a professional final product. At the same time, the Clinic experience helps students improve their technical writing and presentation skills as they work with a customer. Clinic also provides opportunities for evaluating economic, environmental, and societal impacts of their work. More details about the Clinic program experience can be found elsewhere [3-6]. Photovoltaic Clinic Project In September of 2010, Kaneka Corporation, one of the world's largest thin-film amorphous silicon solar module manufacturers, sponsored the development of a research test bed through the Engineering Clinic to evaluate its multi-junction technology solar PV modules. This sponsored project was an ideal fit to Rowan University’s Clinic program. A one-year project was defined as a multidisciplinary project available to junior and senior students from the four Engineering disciplines (ChE, CEE, ECE, and ME). The objective of the project was to design, permit, specify, install, and monitor a 1.65kW multi-junction PV system. This Clinic project provided students with the opportunity to research a cutting-edge technology solar module design, implementation, and performance assessment. One of the motivations for sitting the system on Rowan Hall, was to produce energy to offset the electricity cost for illuminate a memorial flagpole for Robert Dusseau, a former Rowan University Engineering student. Once Clinic students complete the design and installation of the array, the system will also generate funds via the Solar Renewable Energy Credit (SREC) program to help supplement a scholarship fund in Robert's name. Solar PV Engineering Clinic Project Overview The design of a solar PV system started with a fundamental review. Clinic students researched and reviewed the basic concepts behind solar PV and the theory of the operation of solar modules in order to gain knowledge and prepare for the assigned project. During their research phase, students learned that a PV system refers to the array of solar modules, their orientation and mounting, wiring and connectors, and the other key components (inverter, switches, fuses) that are used to convert sunlight into electric power and provide it to the grid. The multidisciplinary nature of the students group (the team included ECE, ChE, and CEE students) provided students with the opportunity to develop cross-over skills. For example, CEE students learned the dialog of power, and ECE students learned the dialog of structures. The design of the PV system consisted of a series of steps that are critical for determining the efficiency of the system in term of its output and in consideration of the system's installation and maintenance costs. The key steps followed for the design of the PV system at Rowan Hall were: 1) Maximize Solar Resource Irradiance can be defined as the measure of the power density of sunlight and is measured in watts per square meter. Irradiation can be defined as the integration of the irradiance over all daylight hours. On a given time or day, irradiance will vary depending on the time of the day, time of the year, weather and shading. Typically, regardless of weather conditions, irradiance in the middle of the summer is much greater than in the middle of the winter. This is due the orbit and inclination of the earth. The inclination of the earth causes the sun to be higher in the sky in the summer than in the winter and therefore longer days during this period and shorter days during winter. Some of the key concepts students learned as part of the project include: solar modules consist of an array of PV cells, which are constructed of a semiconductor material (usually silicon). Sunlight is made up of energy packets known as photons; each individual solar cell is designed with a positive and negative layer in order to create an electrical field. As photons from sunlight are absorbed into the cell, they provide enough energy to allow for a flow, or current, of electrons towards the bottom of the cell and ultimately through the cell’s junction in the form of electricity. The generated current of electricity comes in the form of direct current (DC). However, electrical grid power is alternating current (AC) and therefore an inverter must be used to convert the current from DC to AC and step the voltage up to the required system voltage level. Efficiency of a PV system depends on the irradiance that it is exposed to. Maximizing the efficiency of a PV system requires that solar modules are installed in an area with no obstructions that may shade the PV array, since shading can significantly decrease the power output of a solar module. The orientation of the PV system is se