1 / 19

ECE 333 Green Electric Energy

ECE 333 Green Electric Energy. Lecture 14 Monthly Clear-Sky Insolation , PV Intro Professor Tim O’Connell Department of Electrical and Computer Engineering. Announcements. Exam 2 is next Thursday , 8:00AM – 9:20AM Change from the original syllabus

beata
Download Presentation

ECE 333 Green Electric Energy

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ECE 333 Green Electric Energy Lecture 14 Monthly Clear-Sky Insolation, PV Intro Professor Tim O’Connell Department of Electrical andComputer Engineering

  2. Announcements • Exam 2 is next Thursday, 8:00AM – 9:20AM • Change from the original syllabus • ECE 431 field trip next Thursday (March 20th) • We are working on a Conflict Exam for Wednesday, March 19th. • Start reading Chapter 5 • Today: Finishing Chapter 4, Starting Chapter 5

  3. Review: Solar Insolation on a Collecting Surface • Direct-beam radiation on the collector face is just a function of the angle between the sun and the collecting surface (i.e., the incident angle q): (4.24) Units are [W/m^2]

  4. Daily, Monthly and Annual Insolation • If we integrate IBC (which varies throughout the year) over a day, a month or a year, we find the energy collected (in kWh, for example) per unit area of collector. • The total energy gathered annually doesn’t vary too much with orientation for fixed collectors • However, the month-to-month numbers can vary greatly depending on the orientation • This is an important distinction depending on what type of solar installation is planned • Grid-connected systems can fluctuate monthly, standalone systems should have flatter supply

  5. Daily, Monthly and Annual Insolation • Annual insolation curves are similar for varying collector orientations • South-facing collectors tend to be the best Σ Figure 4.31

  6. Daily, Monthly and Annual Insolation • Daily insolation curves vary with orientation much more than annual curves A collector with S = L has the flattest curve Larger tilt angles get more insolation in the winter, smaller angles get more in the summer Figure 4.32

  7. Improvement Due to Tracking • Adding a tracking system (one- or two-axis) can have large benefits Figure Not in Text • Two-axis only marginally better than one-axis during the summer months Figure:

  8. US Annual Insolation Champaign averages about 4.7 [kWh/(m^2-day)]

  9. Illinois Insolation Data [kWh/(m^2-d)] Daily average = 4.69 [kWh/(m^2-day)] Yearly average = 1.7 [MWh/(m^2-yr)] “Evaluation of the Potential for Photovoltaic Power Generation in Illinois” by Angus Rockett, 2006

  10. Interpreting the Data • Units on insolation maps are [kWh/(m^2-day)] • DEFINE:1-sun of insolation = 1 kW/m^2 • Estimate of the insolation at the Earth’s surface on a bright sunny day with the sun high in the sky • Other values of insolation can be referenced to this standard • 1 sun of insolation for 1 hour (or, 1 hour of full sun) gives 1 kWh/m^2 • Champaign’s yearly average isolation of 4.7 kWh/(m^2-day) can be interpreted as 4.7 hours of full sun per day, on average.

  11. Worldwide Annual Insolation [MWh/(m^2-yr)] Champaign is about 1.7 In 2011 worldwide PV capacity was about 70GW, with about 1/3 in Germany (25GW), 12.8 GW in Italy, 5 GW in Japan, 4.5 GW in Spainand 4 GW in the US http://www.ren21.net/Portals/97/documents/GSR/GSR2012_low%20res_FINAL.pdf

  12. End of Chapter 4 • Questions?

  13. Photovoltaics (PV) Photovoltaic definition- a material or device that is capable of converting the energy contained in photons of light into an electrical voltage and current University of Illinois Solar DecathalonHouse “Gable Home” – 2nd place overall in 2009 "Sojourner" exploring Mars, 1997 Rooftop PV modules on a village health center in West Bengal, India http://www.solardecathlon.uiuc.edu/gallery.html# http://www1.eere.energy.gov/solar/pv_use.html

  14. Photovoltaics • Illinois 2011 Solar Decathlon house “Re_home” • Now resides on South First Street http://www.solardecathlon.gov/past/2011/team_illinois.html#nogo

  15. PV History Edmund Becquerel (1839) Adams and Day (1876) Albert Einstein (1904) Czochralski (1940s) Vanguard I satellite (1958) Today… Cost/Capacity Analysis (Wp is peak Watt) http://www.nrel.gov/pv/pv_manufacturing/cost_capacity.html

  16. PV System Overview • A solar “cell” is a diode • Photopowerconverted to DC • Shadows & defects convert generating areas to loads • DC is converted to AC by an inverter • Loads are unpredictable • Storage helps match generation to load Shadows

  17. Some General Issues in PV • The PV device itself • Efficiency, cost, manufacturability/automated production, testing • Encapsulation • Cost, weight, strength, yellowing, etc. • Accelerated lifetime testing • 30 year outdoor test is difficult • Damp heat, light soak, etc. • Inverter & system design • Micro-inverters, blocking diodes, reliability

  18. What are Solar Cells? Load - + • Solar cells are diodes • Light (photons) generate free carriers (electrons and holes) which are collected by the electric field of the diode junction • The output current is a fraction of this photocurrent • The output voltage is a fraction of the diode built-in voltage p-type n-type Open-circuit voltage Voltage Maximum Power Point Current Short-circuit current

  19. Standard Equivalent Circuit Model Where does the power go? Series resistance (minimize) Photocurrent source Shunt resistance Load Diode (maximize)

More Related