OBJECTIVES

The overall objective of this course is to apply engineering science principles for analysis of solar energy systems. Upon successful completion of the course, students will have the ability to:

• identify and evaluate the role of solar energy technologies to address energy needs, recognizing both the opportunities and limitations.
• identify and analyze available solar radiation resources for conversion to useful energy. Absorbed solar radiation, which can be converted to either thermal or electrical energy, depends on location, time, sky conditions, and the properties of the collection material.
• analyze the conversion of solar radiation to useful energy and its subsequent utilization and storage.. For thermal systems, the absorbed energy is transferred to a working fluid, which can be analyzed using principles of thermodynamics and heat transfer. For PV systems, the absorbed energy is converted to electricity, which can be analyzed using principles of electrical circuits.
• identify and evaluate PV technologies and systems for grid-tied and stand-alone applications, including residential and commercial buildings as well as remote and developing world applications.
• identify and evaluate solar thermal technologies and systems. Specifically, you will understand the application of solar energy for thermal applications, including water heating, space conditioning, and process heating.
• identify and evaluate concentrating solar power systems for both building and utility-scale applications. While you will get most experience with linear parabolic trough collectors, the principles will also apply to dish and power tower applications.
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EVALUATION

Your understanding of the course material and your ability to apply the material to engineering problems will be evaluated through a combination of quizzes and projects. One quiz will be given at the end of each course day for a total of five quizzes. A course project, described below in more detail, will provide hands-on learning by applying to course principles and techniques.

PROJECTS

Students will complete one small homework project and one final project during the course. The projects will be completed in teams of 2-3 students. The homework project will be completed on the first day of the course and will consist of developing a spreadsheet tool to calculate the solar resource striking an arbitrary surface. For the final project, students will design, analyze, and/or evaluate solar energy technologies or system applications. Student teams are welcome to develop their own project ideas with the approval of the instructor or select from the following choices.
The final project deliverable will be a presentation in PowerPoint format. A copy of presentation material will be submitted to the instructor for evaluation. The project grade will be determined based on equal weighting of the following considerations:

• Understanding: use of resources to develop understanding of project, independent evaluation of contributing factors, demonstrated understanding of factors affecting project problem.
• Engineering Analysis: evaluation of project requirements, analysis of alternatives, appropriate level of analysis for project tasks.
• Tool Usage: appropriate use of analysis and simulation tools
• Presentation Quality: clear problem description, organized approach, clear presentation of results, quality of graphics and images.
• Teamwork:  uniformity of contributions from team members, utilization of diversity of team background

Passive Solar Building Design

Students develop an energy-efficient building design that uses passive solar heating and cooling strategies to minimize the need for HVAC equipment energy use. Given a set of building requirements – building usage, size, and location – the team will select house footprint shape, envelope materials and insulation characteristics, window sizes and locations, window shading devices, and internal thermal mass quantities and distributions. The designs will be developed with the use of building energy simulation programs, such as Energy-10 or eQUEST, provided by the instructor. The teams are welcome to identify their building requirements or can select from the following

• a 160 m2 single-family affordable home for Bedouins in the deserts of the Middle East or indigenous people of Mexico
• a four-story apartment building in Oslo or Mexico City (or anywhere else) with sixteen 80 m2 units
• a 1500 m2 office building in Monterrey or Istanbul or Denver (or anywhere else)

PV or Solar Thermal System Design

Students develop a design of a solar energy system to meet a specific set of application needs. Given the application needs, which determine the load on the system, students layout the system configuration, identify component characteristics, and select and size system components. The teams will then perform a cost benefit analysis to evaluate the economic benefits. The teams are welcome to identify their own application requirements or can select from the following.

• a solar thermal system to meet the hot water needs of a building. Examples buildings includea small hotel, a residence, the university offices or student housing (maybe in a different location).
• a grid-tied PV system that meets a building or process load, but also interacts with the electrical grid. The evaluation might include the contributions to the utility load profile and an economic assessment under different regulatory conditions. The design could be based on a building-integrated system where the constraints may be significant.
• a stand-alone PV system for application in developing communities. Specific applications might include water pumping, a health center, a refrigeration system, or a remote school. Size the PV and batteries for load and resource.

Village Power System Design

Students design a power system to meet the needs of a remote village. The students identify the load requirements and select among a variety of power system to meet the needs. Options include solar PV, as well as diesel generators, and wind turbines, with and without battery storage. These projects will use the HOMER program to identify the economically optimal design for the particular load, resources, and costs.

CSP System Analysis

Design a 50 MW CSP power plant and estimate the cost of the system necessary to compete with electricity production at a cost of $0.10/kWh. While such a design can involved very complicated analysis of both the CSP system and its power block, performance estimates can be obtained with relatively simple calculations and informed assumptions. It is also suggested the Solar Advisor Model (SAM) be used to analyse system performance and evaluate alternative designs.

COMPUTER TOOLS

Design and analysis of solar energy systems are not performed by hand with pencil and paper alone. Rather, there are many computer-based tools available to the engineer.  Some of these tools are comprehensive computer simulation programs that calculate system loads and performance hour-by-hour throughout the year. Other tools provide an environment or component models that allow faster calculation of user-defined problems. Others are simple tools for preliminary design calculations. While these tools will not be used by all students, individual project teams will be encouraged to use them as appropriate.

• Spreadsheet programs, specifically Microsoft Excel, will be used for solar geometry calculations and simple PV sizing calculations. In addition to the well-known calculation capabilities of these programs, we may also explore using VisualBasic programs to extent Excel beyond simple spreadsheet calculations.
• TRNSYS (pronounced “tran-sis”) is a modular simulation package specifically developed for transient simulation of solar energy systems. In use since 1973, it is arguably the most well-known solar system research tool in the world. Its modularity makes it a flexible and powerful research tool. Unfortunately, its complexity precludes us from considering it for use in this course.
• fChart and PVfChart are two design tools that predict the performance of a solar system in meeting specified loads based on monthly calculations. Each program estimates the fraction of the load met by the solar system – the f in fChart – and performs basic life cycle cost calculations. These tools are particularly useful for system sizing.
• Energy-10 and eQUEST are two building energy simulation programs that are commonly used in the schematic design of building energy performance. While these programs are not specifically designed for passive solar heating systems anlaysis, they are effective for evaluating the impact of window size and location, window shading, and thermal mass.
• HOMER (Hybrid Optimization Model for Electric Renewables) is a software tool originally developed at the US National Renewable Energy Laboratory (NREL) (http://www.homerenergy.com). The program simplifies the task of evaluating design options for both off-grid and grid-connected power systems for remote, stand-alone, and distributed generation (DG) applications. HOMER's optimization and sensitivity analysis algorithms allow you to evaluate the economic and technical feasibility of a large number of technology options and to account for variation in technology costs and resource availability.
• Solar Advisor Model (SAM) is another software tool developed at NREL for the analysis of utility-scale PV and CSP systems and their economics (http://www.nrel.gov/analysis/sam). The tool allows relatively detailed analysis of alternative technologies and has often been used as a policy analysis tool.
• RETScreen is a spreadsheet-based tool for screening renewable energy technologies developed by Natural Resources Canada (http://www.retscreen.net). The software, provided free-of-charge, can be used worldwide to evaluate the energy production and savings, costs, emission reductions, financial viability and risk for various types of Renewable-energy and Energy-efficient Technologies (RETs). The software (available in multiple languages) also includes product, project, hydrology and climate databases, a detailed user manual, and a case study based college/university-level training course, including an engineering e-textbook.

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Instructor: Michael J. Brandemuehl, PhD, PE

University of Colorado at Boulder Civil Environmental, and Architectural Engineering