EE 237 : Solar Energy Conversion

Transcription

1 EE 237 : Solar Energy Conversion Logistics Books Syllabus & Grading 1

2 Logistics Class Meets : M and W : 4:15-5:30pm Meets Where? : Instructors : Aneesh Nainani (Applied Materials/Stanford) nainani@stanford.edu Office Hours : M and W : 6-7pm, CISX-327 Krishna Saraswat (Stanford) saraswat@stanford.edu TA : Raisul Islam (raisul@stanford.edu) Office Hours : M 2:30-4pm, Th 3:30-5pm, Packard 106 2

3 Logistics: Class Website Website : Uses the newly Class2Go platform read video, interactive forum and exercises and big data applied to Stanford classes piazza integrated for discussions All problem set submissions by soft copy on the class website No class on: April 8 th, May 27 th Extra class: April 12 th and May 31 st 3

4 Logistics: Class format EE237 Typical 3 unit Stanford class - 50 min classroom interaction / unit - 2 lecture/wk (75 min) - 3 lecture/wk (50 min) hr/week of work on problem sets / projects ~ 75 min of short videos each week - 20 lectures - 5 guest lectures - 15 lectures (50% time on problem solving) hr/week of work on problem sets / projects 4

5 Logistics: Class format Adapted flip class room model Short videos are used to supplement class lectures Frees up class time for interactive sessions and discussion in class 5 guest lectures from engineers / entrepreneurs in PV Equation derivation etc happens in the videos, in class the focus is on discussing the physics and economics of PV Total : 20 lectures and ~100 short videos 5

6 Class Videos ee237.class2go.stanford.edu YouTube : Download Sync On your tablet / smartphone Subscribe 6

7 Class Videos PS1 PS2 Midterm PS3 7

8 Class Videos (last 6 months) US China 0 India 6500 S. Korea 1500 Taiwan

9 Books : Online & Free for Stanford Excellent book for introduction to PV Broad introduction not just PN junction solar cell 9

10 Books : Online & Free for Stanford Excellent book for semiconductor physics part of PV Broad introduction not just c-si based PN diode Slightly technical 10

11 Books Follow at least one book along with the class notes Additional reading from web resources and handouts will be prescribed as we go along All books / handouts FREE 11

12 Grading Grade : Letter (ABCD) or CR/NC 4 problem sets 40% Problem Set 1 : Week Problem Set 2: Week Problem Set 3: Week Problem Set 4: Week Project : 20% End Term : 40 % 12

13 Team of 3-4 students Project Each team will receive 25 c Si solar cells (Ever Bright cells), tabbing wire, bus wire, solder, and flux. You will also have some basic mechanical materials available to build simple concentrators. Each item you use will have a cost, you have to tally up the total to get a total $ (don t worry, you don t have to pay) You can design your panel to be tracking (1D or 2D), but the tracker will have a $/m2 associated with it. Your goal is to achieve the lowest $/Wh. 13

14 EE237: Bird Eye View Q: Assume ideal cell, each absorbed photon is collected, What will be efficiency of the solar cell? A: 100 % Solar Cell A. 32 % 14

15 Solar Radiation 15

16 Effect of bandgap 16

17 Solar Cell Efficiency Optical-Electrical Energy Conversion Efficiency = Solar Spectrum ElectronEnergy(Output) PhotonEnergy(Input) Energy Conversion Efficiency of Silicon Cell < E g Silicon 1 Junction Silicon Solar Cell > E g Max. Theoretical Efficiency ~32% 17

18 Week 1 Motivation - Overview - Real cost of solar (energy payback time) Basic physics of solar energy conversion - Nature of sunlight - Basic operation of a solar cell and loss mechanisms - Schockley-Queisser Limit and tandem cells 18

19 EE237: Bird Eye View Mirrors much cheaper than solar cell Cell efficiency increases with concentration Q: What's the limitation of this approach? 19

20 Week 2 Light trapping, light concentration and tracking - Etendue conservation, limits to concentration, types of concentrators - Tiedje/Yablonovitch limits to light trapping and current/future approaches 20

21 EE237: Bird Eye View Q: Most of the solar cell available in the market today, look very different from what you can buy in the market, why? 21

22 Week 3-5 Crystalline PV Technologies (lectures 5-9) - Silicon feedstock - Process Technology - Basic design of a c-si solar cell - Factors that limit efficiency - Surface passivation - c-si device designs - Multi junction III-V solar cells 22

23 EE237: Bird Eye View ~ 1/3 rd of the cost coming from cost of silicon wafer 23

24 Week 6-7 Thin-Film PV Technologies - Single junction a-si: carrier collection vs. light absorption. LID. - a-si tandems and triple junction cells - CdTe and CIGS solar cells - New approaches: organic PV, nanostructured PV, etc α-si CdTe CIGS OPV 24

25 η ~ 23 % EE237: Bird Eye View η ~ 20 % Q: What is the efficiency of the module? 25

26 Week 8 PV Systems - From cell to module (materials, efficiency losses) - Installations: sizing, effects of mismatch - Effect of shading and soiling - Inverters, microinverters and DC/DC conversion Central inverter Micro-inverter 26

27 Q: What is this? How does it compare to PV? 27

28 Week 9 Solar Thermal and Thermo- Photovoltaics - Principles of solar thermal energy conversion - Parabolic through, power tower and dish - Thermophotovoltaics 28

29 Week 10 Theoretical Limits and New Ideas - Ultimate solar conversion efficiency - Intermediate gap cells, luminescent concentrators, impact ionization, etc. 29

30 What can you expect to learn from this class? Solid foundation of solar energy conversion Broad overview of all PV technologies: advantages and pitfalls of each Understand the economics, system level issues, etc. PV is not just about a PN junction Understand where the main challenges are and opportunities to make the next big thing! By the end of the quarter you will be comfortable reading publications like and Greentechmedia and papers from Progress of Photovoltaic, PVSC etc. 30