Model-based design and optimization of solar energy technologies Raymond A. Adomaitis Chapter 0 1/27 Who am I? Ray Adomaitis Professor, University of Maryland Department of Chemical & Biomolecular Engineering Institute for Systems Research Maryland NanoCenter Maryland Energy Innovation Institute Background: BS, PhD Illinois Institute of Technology; postdoc at Princeton University Research: Simulation-based design of thin-film processes for energy and spacecraft applications Teaching: Solar energy, chemical engineering process design, computations Globex: I have taught this class at PKU in 2013, 2016, and now in 2019 2/27 27,000 undergraduate and 11,000 graduate students, 4200 faculty map university of maryland college park - Google Maps 6/30/13 12:46 PM To see all the details that are visible on the screen, use the "Print" linkFounded next to the map. in 1856 https://maps.google.com/maps?client=safari&oe=UTF-8&q=map+dc&ie=UTF-8&hq=&hnear=0x8…f6e45b:0xc2524522d4885d2a,Washington,+DC&ei=8V_QUci5OsrOkwX1g4DgBA&ved=0CCsQ8gEwAA Page 1 of 2 3/27 Course overview Course management Homework, exams, grading Textbook Software Motivation for this course Course content Draft schedule 4/27 Course management See class syllabus 5/27 Course notes Course lecture notes will evolve while the class is taught. The starting point for this class will be classNotes.pdf. A look at the textbook, current version 6/27 Course software Course software is written in Python and was converted to a web-based interface in summer of 2013. It continues to be upgraded and can be found at http://dev.eng.umd.edu/adomaiti Name: solar Password: PKUsolar2013 7/27 Class description The emphasis of the class is on developing a conceptual understanding of the device physics and manufacturing processes of crystalline and thin-film photovoltaic cells, and to develop elementary computational skills necessary to quantify solar cell efficiency. The class material includes detailed, system-level energy balances necessary to understand how solar energy fits into the complete energy generation, conversion, and storage picture. Quantitative comparisons of PV technology to solar chemical conversion processes and biofuels are made. 8/27 Energy - basic concepts The conversion of solar radiant energy to electrical, chemical, or kinetic energy is central to our class... ....so starting with a review of the basics of energy, power, and radiant intensity unit definitions makes sense. First, consider the central focus of this class: 9/27 The architecture of a typical Si PV cell hυ e- n0 - n 1 + - n-type n2 + + + h e + - - - - emitter + - h e Ie,sc h+ e- p-type I h,sc h+ e- base + 10/27 2 How do we develop mathematical models describing the electrical power produced by PV cells? 3 How do we engineer the PV cell components to optimize cell performance? 4 How do we expand our fundamental knowledge of solid-state PV devices to electrochemical and biological systems? PV cell issues Basic questions we seek to answer include 1 How do we relate photon energy and flux to the electrical power produced by the PV cell? 11/27 3 How do we engineer the PV cell components to optimize cell performance? 4 How do we expand our fundamental knowledge of solid-state PV devices to electrochemical and biological systems? PV cell issues Basic questions we seek to answer include 1 How do we relate photon energy and flux to the electrical power produced by the PV cell? 2 How do we develop mathematical models describing the electrical power produced by PV cells? 11/27 4 How do we expand our fundamental knowledge of solid-state PV devices to electrochemical and biological systems? PV cell issues Basic questions we seek to answer include 1 How do we relate photon energy and flux to the electrical power produced by the PV cell? 2 How do we develop mathematical models describing the electrical power produced by PV cells? 3 How do we engineer the PV cell components to optimize cell performance? 11/27 PV cell issues Basic questions we seek to answer include 1 How do we relate photon energy and flux to the electrical power produced by the PV cell? 2 How do we develop mathematical models describing the electrical power produced by PV cells? 3 How do we engineer the PV cell components to optimize cell performance? 4 How do we expand our fundamental knowledge of solid-state PV devices to electrochemical and biological systems? 11/27 Renewable power 09/02/13 09/02/13 2500 45000 geothermal demand wind scaled renewables solar 2000 40000 1500 35000 MW MW 1000 30000 500 25000 0 20000 5 10 15 20 5 10 15 20 time of day time of day Renewable energy production (left) and overall electricity demand (right) in California during a 24 hour period in late summer 2013. Source of data 12/27 Energy - basic concepts We note: 1 Renewable energy sources introduce a high degree of dynamic (in time) variability in the power supply: 1 wind variations 2 clouds passing between the sun and solar modules 2 The temporal variations have multiple time-scales: 1 higher-frequency fluctuations with time scales measured in seconds or minutes 2 diurnal variations that take place over the day 3 There is a strong incentive to include energy storage elements in the overall design to reduce the power fluctuations and to allow for peak power delivery at the 5 pm demand peak. Bottom line: 1 PV and other elements cannot be studied in isolation 2 renewable resources require integration of a number of energy generation, conversion, and storage technologies 13/27 Chapter 1: Energy and thermodynamics review Account for wide range of student backgrounds Course motivation Elementary review of thermodynamics Base SI units Derived units of energy and power, with emphasis on quantities relevant to electric circuit analysis and radiant energy 14/27 Chapter 2: The sun The logical starting point Solar spectrum Radiant flux as a function of time, date, and latitude Spectral irradiance, irradiance, insolation Atmospheric absorption models Time-averaged quantities, NREL and other insolation data 15/27 Chapter 3: Transient energy balances Crucial to modeling PV cells and energy conversion systems Conservation of energy - steady versus dynamic processes Modeling PV and energy storage systems Modeling solar thermal systems, closed and open 16/27 Chapter 4: PV device physics Following the charge carriers Band structure of metals, semiconductors, and insulators p-n junctions and derivation of the diode equation Charge carrier diffusion and drift Photon interactions with semiconductors 17/27 Chapter 5: Cell architecture and manufacturing The mc-Si PV cell Manufacturing the Si substrate Manufacturing steps for an elementary PV cell Advanced cell architectures Thin-film PV Amorphous Si CIGS - Copper indium gallium (di)selenide CdTe - Cadmium telluride 18/27 Chapter 6: The equivalent circuit model Computing PV cell power Cell current-voltage characteristics; the equivalent circuit Using module measurements to identify PV cell model parameters Real cells: modeling nonidealities 19/27 Chapter 7: Quantum efficiency How effectively are photons converted to electrical power? Internal/external quantum efficiencies Theoretical computations Multijunction devices Anti-reflection coatings 20/27 Chapter 8: Arrays of PV cells PV cell interconnection and unexpected behavior Arrays of cells, modules Shaded cells Blocking diodes and other electrical elements 21/27 Chapter 9: Dye-sensitized PV cells A move towards electrochemical systems and alternate charge-separation mechanisms Electrochemistry overview Operating principles The equivalent circuit model 22/27 Chapter 10: Photoelectrochemical cells Use solar energy to directly create storable fuels Electrolysis PEC cell electrochemistry for solar water splitting Modeling PEC cell performance 23/27 Chapter 11: Photosynthesis and biofuels Comparing nature to engineering Overview of natural and artificial processes Ethanol and other biofuel production technologies Comparative mass and energy balances for biofuel production routes: what is the overall efficiency? 24/27 Chapter 12: Review of numerical techniques This is an engineering class, so quantitative solutions are expected Interpolation and quadrature Finite differences and the Euler integrator Newton's method Solution of elementary differential equations Note: You are free to use what software you like (MatLab, Python, C, VB, Excel, etc.) =) You may want to review your computing/plotting skills asap 25/27 How will we cover all this? Again, see class syllabus and HW assignment schedule 26/27 Next lecture Objective: review Chapter 1 concepts and terminology. Base and derived units Basic thermodynamics review 27/27.