ECET 4801 PV Systems Design and Applications (3 Credit Hours)

Transcription

1 ECET 4801 PV Systems Design and Applications (3 Credit Hours) I. Course Overview The design of solar electric systems is often subject to several considerations. Principal among these is the specific energy need that the system will b required to meet. This consideration together with the fact that solar electric systems are opportunistic gives rise to various forms of PV electric systems. In this course, various PV systems will be studied in other to acquaint the student of the various considerations used in system design. Examples/applications will be used to illustrate critical design considerations and discretions. II. Expected Learning Outcomes The central objective of this course is to equip the student with the knowledge and skills required to design and implement various forms of PV systems for different applications and load types. The student who successfully completes this course will therefore be expected to have gained certain competences. These competencies include a mixture of abilities to explain certain theoretical concepts in PV systems and to implement some practical applications of PV systems. Behavioral objectives of this course include ability to: Determine appropriate type of system for a given application Size appropriate system to meet demand Determine a system with operating plan for a limited budget Design and implement a stand alone PV system Design and implement a PV/Gen hybrid system Design and implement a PV village power system Design and implement a utility interactive PV system III. General Information for Students Textbook The primary textbook for this course is Photovoltaic Systems Engineering by Roger Messenger and Jerry Ventre, CRC Press, latest edition. This is a required test book. Reference materials are listed in the pertinent modules syllabi. Students are advised to see the department s student hand book and the university catalogue for applicable rules and regulations as the classes for this course will be conducted strictly according to those rules and regulations. Other rules of conduct may be announced by the instructor. Prerequisites A fundamental knowledge of electrical systems terminology and properties is required. Also required is an understanding of the fundamentals of photovoltaics science. The student therefore must have successfully completed ECET 3801 before enrolling in this course. Electrical wiring skills will be advantageous. IV. Instruction Units/Modules This course is designed to develop the cognitive skills of the learner. No extensive laboratory exercises are involved. A full description of each of the following units of instruction covered in the course is given in the module syllabus: Unit 1. Load analysis and system sizing Unit 2. System electronics and balance of system (BOS) components Unit 3. Site assessment and selecting a system design Unit 4. Adaptation of mechanical design to site Unit 5. Adaptation of electrical design to site and system type Unit 6. Stand alone PV systems Design Unit 7 PV/Gen hybrid system design Unit 8 Village power systems Unit 9 Utility interactive PV systems

2 V. Evaluation of Learning Outcome A variety of instruments and methods will be used to assess the pertinent task analyses or competencies the student has acquired. These include a test at the completion of each instructional module; a final comprehensive examination to measure the ability of the student to retain and synthesize information from the various modules for an integrated body of knowledge; and a design project to evaluate the students ability to derive ideas from what was learnt and to formulate concept based on knowledge gained from the course. Specific instruments for evaluating the effectiveness of the instructional activities and strategies for each unit are listed in the modules syllabi.

3 VI. Course Specifications # Section of Task Analysis 1 System analysis & design 2 System design; PV System assembling 3 Site assessment; System analysis & design 4 System wind load analysis, System design 5 System design, Compliance with regulation and codes Instruction Unit Load analysis and system sizing System electronics and balance of system (BOS) components Site assessment and selecting type of system Adaptation of mechanical design to site Adaptation of electrical design to site and system type 6 System design Stand alone PV systems Design 7 Hybrid system design, Gen use optimization 8 Demand/load calculation, load shading 9 Grid interconnection PV system design PV/Gen hybrid system design Village power systems Utility interactive PV systems Level of Training/ priority Table1. Course Specifications Matrix % Course time Allotted Time (Weeks) Location and/or Facilities Very High Lecture room, laboratory Very High Lecture room, Laboratory High 07 1 Lecture room, Field Very High 14 2 Lecture room, field, laboratory Very High 14 2 Lecture room, laboratory High Lecture room, Laboratory high Lecture room, Laboratory high 14 2 Lecture Room, field high 07 1 Lecture room, field Total Materials and Supplies Pyranometer, PV modules, MPT Charge controllers, Inverters, etc pyranometer Geometry set Mechanical tools PV arrays, BOS, electrical parts PV arrays, BOS PV arrays, Generator set PV arrays, BOS, Generator set PV arrays, BOS Resources/ references NSol! PV System Sizing Program, V2.8, Orion Energy Corporation, Ijamsville, MD. UL 1741: 1999, Standard for Static Inverters and Charge Controllers for use in PV Systems Taping into the sun: Today s application of PV technology. Post, H. N., Low cost structures for PV arrays, Proc. 14 th IEEE PV Specialists Conf. Jan. 7-10, Design Guide & Catalog, Alternative Energy Engineering, Redway, CA, 1997 Stand-Alone PV Systems: A handbook of Recommended Practices, Sandia National Lab Onan Corporation, Gensize TM 96 Software for sizing gensets Design Guide & Catalog, Alternative Energy Engineering, Redway, CA, 1997 Wills, R. H., The Interconnection of PV Pwr Sys with Utility Grid. An overview for Engineers, SNL.

4 Instruction Unit One Load Analysis and System Sizing Introduction It is important to operate the PV system near its maximum power points. This requires that all the power produced by the system be used by the load at all times. This is a challenging problem since loads are not generally adjustable in quick order as system availability may fluctuate. The I V characteristic of the ideal load will, however, always intersect with the I V characteristics of the PV array at the maximum power point for various illumination levels or times. This unit discussing how to obtain an array/load match such that the intersection of their I V characteristics will not depart significantly from the maximum power point of the PV source during desired operation times. Also presented in this unit is load classification and analysis and a detail discussion of system sizing. Required Entry Behavior of PV systems. Students are expected to be familiar with the fundamentals Use the maximum power tracker, MPT. Classify PV system loads Determine system availability Size PV systems for specific applications Pyranometer, PV modules, MPT Learning Activities and Strategies This unit consists of classroom and field activities. The classroom presentations will be punctuated with demonstrations both inside and outside the classroom. The following is a tentative plan for covering the instructional materials for achieving unit objectives: PV system load 60 minutes Operation of the MPT 45 minutes PV system availability 60 minutes System sizing 45 minutes Hour Test 60 minutes 270 minutes (1.5 weeks) I V characteristics and maximum power point. Variation of a resistive load to track maximum power from a PV array. Hour Test Reference Materials NSol! PV System Sizing Program, V2.8, Orion Energy Corporation, Ijamsville, MD.

5 Instruction Unit Two System Electronics and Balance of System (BOS) Components Introduction The basic electronic components of PV systems are introduced in this unit. These components include charge controllers, inverters and electronic maximum power trackers. The description and simplistic explanation of the operation of each of these components are given. In the explanation of a component, emphasis is placed on system performance requirements and how best to achieve them. Also discussed in this module are the balance of system (BOS) components. These components include mounting materials for modules, wiring components, battery containers, grounding connections and lightening protectors. Required Entry Behavior Students are expected to be familiar with the fundamentals of PV systems. Proficiency in electrical wiring and knowledge of power electronics will be very helpful. Describe electronic maximum power tracker, MPT and explain how it operates. Describe the circuitry and function of various inverter circuits Describe the essential features of charge controllers and how they operate Construct a PV system Pyranometer, PV modules, MPT, Inverter, charge controller, BOS components Learning Activities and Strategies This unit consists of classroom and laboratory activities. The classroom presentations will be followed with laboratory exercises. The following is a tentative plan for covering the instructional materials for achieving unit objectives: Charge controllers 60 minutes Maximum power trackers 30 minutes Inverter circuits 60 minutes Balance of system components 30 minutes PV system assembling 90 minutes Battery charging and discharging. PV system construction. 270 minutes (1.5 weeks) Group project/project report Reference Materials UL 1741: 1999, Standard for Static Inverters and Charge Controllers for use in PV Systems

6 Instruction Unit Three Site Assessment and Selecting a System Design Introduction The purpose of this unit is to acquaint the student with some of the considerations used in the design of PV systems. Chief among these considerations are the conditions of the site, including the solar resources at the site. Other site assessment factors to be considered include environmental impact, safety and aesthetics. A pre step towards system design is analysis. Since a design problem does not necessarily have a single best solution, the designer should consider all alternative methods of achieving the purpose of the system. This unit presents an exercise in the selection of alternatives. The tradeoffs and compromises among competing parameters such as reliability, performance and cost, as well as the discretions of the designer are discussed. Required Entry Behavior Students are expected to be familiar with the fundamentals of PV systems, PV system economics, and solar radiation and insolation. Select an appropriate PV system for a particular load/application. Determine the environmental impact of a system Determine system availability and reliability for a particular site Optimize system performance at a site. Pyranometer, Solar radiation map Learning Activities and Strategies This unit consists of classroom and field activities. The classroom presentations will be punctuated with demonstrations both inside and outside the classroom. The following is a tentative plan for covering the instructional materials for achieving unit objectives: Site assessment 30 minutes Environmental effects of PV system deployment and operation 30 minutes Cost considerations 60 minutes System reliability considerations 30 minutes Quiz 30 minutes 180 minutes (1 week) Measurement of solar radiation Determination of solar radiation/solar resources using the radiation map Quiz Reference Materials Taping into the sun: Today s application of PV technology.

7 Instruction Unit Four Adaptation of mechanical design to site Introduction This unit emphasizes the role and importance of mechanical design components of the PV system. The purpose is to encourage the student to pay as much attention to mechanical aspects of the system design as she would to the energy convention aspect. The life expectancy of PV modules is between 20 to 25 years. It is important that the other components of the system, including the mechanical components, have lifetimes equivalent to those of the PV modules. Furthermore, the mechanical design requirements of the system must also be consistent with the performance requirements as well as the operational requirements for a robust design. This unit explores the design requirements of the mechanical components of the PV system. Required Entry Behavior Students are expected to be proficient in elementary Euclidian geometry and trigonometry. Knowledge of mechanical and chemical properties of materials and statics will be helpful. Describe the important properties of materials. Establish mechanical system requirements Compute mechanical forces on system Design array mounting systems Mechanical tools, geometry sets Learning Activities and Strategies This unit consists of classroom and field activities. The classroom presentations will be punctuated with demonstrations both inside and outside the classroom. The following is a tentative plan for covering the instructional materials for achieving unit objectives: Important properties of materials 60 minutes Mechanical system design requirements 60 minutes Computing mechanical forces 60 minutes Array mounting system design 120 minutes Hour Test 60 minutes 360 minutes (2 weeks) Array mounting system design and implementation Hour Test Reference Materials Post, H. N., Low cost structures for PV arrays, Proc. 14 th IEEE PV Specialists Conf. Jan. 7-10, 1980

8 Instruction Unit Five Adaptation of electrical design to site and system type Introduction Electrical codes and standards are generally established for the safety of electrical systems. These codes and standards also protect knowledgeable technicians and other electrical workers from safety hazards as well as contribute to system reliability and efficiency. Since PV systems are capable of generating sufficiently high voltages that potentially pose electrical safety hazards, they are included in electrical codes and standards. This unit of instruction is an overview of wiring and code compliance requirements of various PV systems for various sites. Required Entry Behavior of PV systems. Students are expected to be familiar with the fundamentals Demonstrate an understanding of the National Electric Code. List some of the codes that may apply to PV installations Discuss the IEEE Code 929 Determine appropriate wiring and other code compliance components PV arrays, BOS, electrical parts Learning Activities and Strategies This unit consists of classroom and field activities. The classroom presentations will be punctuated with demonstrations both inside and outside the classroom. The following is a tentative plan for covering the instructional materials for achieving unit objectives: The National Electric Code (NEC) 60 minutes Voltage Drop and Wire Sizing 60 minutes Switches, Circuit Breakers, Fuses and Receptacles 60 minutes Ground Fault, Surge and Lighting Protectors 60 minutes IEEE Standard 929, and Other Codes 60 minutes Hour Test 60 minutes Wire sizing for stand alone PV system. 360 minutes (2 weeks) Hour Test Reference Materials Design Guide & Catalog, Alternative Energy Engineering, Redway, CA, 1997

9 Instruction Unit Six Stand alone PV systems Design Introduction This unit introduces the student to the design process for a complete stand alone PV system. As part of the learning by example exercise, a design implementation will be explored, including design optimization and life cycle cost analysis to illustrate the interactive process that produces reasonable system cost effectiveness. Several examples of stand alone systems (applications) will be presented. Required Entry Behavior of PV systems. Students are expected to be familiar with the fundamentals Design a simple stand alone PV system. Optimize a system design. Determine system life cycle cost Compare design options based on performance and cost effectiveness. PV modules, BOS, electrical parts Learning Activities and Strategies This unit consists of classroom and field activities. The classroom presentations will be punctuated with demonstrations both inside and outside the classroom. The following is a tentative plan for covering the instruction materials for achieving unit objectives: Design Specifications/Introduction 15 minutes Load Determination 60 minutes Battery Selection 60 minutes Array Sizing and Tilt 45 minutes Controller, Inverter and/or dc:dc Converter Selection 30 minutes Wire, Fuse and Switch Selection 30 minutes Balance of System Component Selection 30 minutes Life Cycle Cost Analysis 30 minutes Total System Design 30 minutes Some Typical Stand Alone PV Applications 30 minutes 360 minutes (2 weeks) ac refrigerator Implementation of a PV system for a 12 cubic-foot 120 V Design project Reference Materials Stand-Alone PV Systems: A handbook of Recommended Practices, Sandia National Lab, Other

10 Instruction Unit Seven PV/Gen hybrid system design Introduction The opportunistic nature of PV systems makes an economic design to meet load requirements or system availability at all times a tricky undertaken. If for example a PV array is installed to meet load requirements for minimum sun availability, then it will result in significant excess generation during periods of high insolation and thus much of the PV output will be wasted during the high sun availability months. To avoid the waste and save cost therefore, one would install array capacity less than required for minimum sun availability and seek other means of meeting margin during periods of low insolation. Furthermore, it has been observed that there is a significant cost increase between sizing a PV system to provide 95% system needs vs. providing 99% system needs. Hence, using a generator for increasing system availability from general to critical may also be cost effective. This unit of instruction investigates the method of choosing alternative generation capacity to supplement the output of the PV array when there is a large discrepancy month-to-month system needs vs. month-tomonth PV generation capacity and/or to for increasing system availability from general to critical in other to reduce overall system cost. Required Entry Behavior of PV systems. Students are expected to be familiar with the fundamentals Design PV/genset hybrid system. Optimize hybrid system operation Perform system cost cycle analysis PV array, genset, Orion Energy APEX 1000 hybrid system Learning Activities and Strategies This unit consists of classroom and field activities. The classroom presentations will be supplemented with demonstrations with PV/gen hybrid system. The following is a tentative plan for achieving unit objectives: Design Specifications 60 minutes Design Implementation/Component Sizing/ Component Selection 90 minutes Generator Operating Cost optimization/hybrid Control system 30 minutes Seasonal or Periodic Battery Discharge 30 minutes Hour Test 60 minutes generator operating cycles. 270 minutes (1.5 weeks) Variation of hybrid system operating points to vary Hour Test Reference Materials NSol! PV System Sizing Program, V2.8, Orion Energy Corporation, Ijamsville, MD. Onan Corporation, Gensize TM 96 genset sizing software.

11 Instruction Unit Eight Village power systems Introduction Electric power needs of off grid communities such as remote villages in developing countries can be met with PV systems. In many instances these communities may be too poor to pay for the systems which will meet their electric power needs. Multilateral agencies and philanthropies have done a lot to help the impoverished communities by funding rural electrification projects using PV systems. It is sometimes more economical to provide electricity to a small community with a central system than with individual stand alone systems. The so called village power system can also increase access to electricity in the community since it can provide power for several community services and facilities than can not be served by the individual stand alone units. This unit of instruction investigates the method for designing and implementing a village power system. The rules of operation are also discussed. Required Entry Behavior Students are expected to be familiar with the design and implementation of PV/gen hybrid systems and stand alone PV systems. Design village power distribution system. Operate a village power system Determine system availability for a given community Size village power system for specific applications Orion Energy APEX 1000 hybrid system Learning Activities and Strategies This unit consists mainly of classroom activities. The following is a tentative plan for covering the instructional materials for achieving unit objectives: Distribution system design 60 minutes Load assessment 60 minutes Power system sizing 60 minutes System operation/load assignment 60 minutes System Optimization 60 minutes Hour Test 60 minutes 360 minutes (2 weeks) Hour Test Reference Materials Design Guide & Catalog, Alternative Energy Engineering, Redway, CA, 1997; Pyramid Hybrid Power Handbook; Other.

12 Instruction Unit Nine Utility interactive PV systems Introduction A number of electric utilities have initiated programs for the installation of utility interactive PV generation. Additionally, in some states, it is becoming cost beneficial for individuals to augment their grid electric service with PV since they can now sell power back to the grid at peak demand period when power is most costly. There is however a number of technical and non technical issues that so far inhibit a widespread of utility interactive PV use. This unit of instruction investigates the barriers to utility interactive PV use. Required Entry Behavior Students are expected to be familiar with the design and implementation of stand alone PV systems. Discuss the non technical barriers to utility interactive PV use. Discuss the technical considerations for connecting PV system to grid Design a small residential utility interactive PV system Learning Activities and Strategies This unit consists mainly of classroom activities. The following is a tentative plan for covering the instructional materials for achieving unit objectives: Non technical barriers to utility interactive PV Systems 60 minutes Technical Considerations for Connecting to The Grid 60 minutes Small Residential utility interactive PV System Design Example 65 minutes 180 minutes (1 week) Home work Reference Materials Wills, R. H., The Interconnection of PV Power System with Utility Grid. An overview for Engineers, Sandia National Laboratories, Albuquerque, MN, 1998.