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Engineering 102. Lecture 8 – Even More Solar Oven. Administration. Tomorrow: Main Lecture meets on the mall the cactus garden (NOTE: location change!) Pick Up Solar Oven Supplies next week Room 200, Engr. Building Thermometer must be returned Tuesday, Mar. 1: No regular class
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Engineering 102 Lecture 8 – Even More Solar Oven
Administration • Tomorrow: Main Lecture meets on the mall the cactus garden (NOTE: location change!) • Pick Up Solar Oven Supplies next week • Room 200, Engr. Building • Thermometer must be returned • Tuesday, Mar. 1: • No regular class • Suggested: team work time • Our classroom is open and I will be there
Administration • Solar Oven Comparisons Team HW due Mar. 1 (pg. 29, Solar Oven Document) • Solar Oven Excel Prediction Model Team HW due Mar. 3 (pp. 30-33, Solar Oven Document) • Excel Spreadsheets: enter angles (trig. functions) in radians, not degrees • First oven testing: Tuesday, Mar, 8 • Meet on the mall near the stage • Bring your team’s oven and thermometer
Administration, cont. • SolidWorks Homework (individual) due Mar. 8 (Part 1, “30 minute Tutorial”) and Mar. 11 (Part 2, other 3 tutorials) • Submit files as pdfs to D2L dropboxes (NOT SolidWorks files!) • SolidWorks Tutors in OSCR lab Mar. 2 through Mar. 11 • Installing SolidWorks on your own computer is optional
Administration, cont. = Lab open and SolidWorks tutor(s) there = Lab closed
Today’s Agenda • Solar Oven Project • Emphasis on the gain, G, from the addition of the reflectors • Effective Presentations
G: The Gain from Reflectors • See pp. 13 – 20 in Solar Oven Document • Remember our VIF* from the last lecture: * Very Important Formula IoAwt a G UwAw + UsbAsb T = Toven – Tambient= The Gain from reflector(s)
G: The Gain from Reflectors Modeling the Gain, G: Figure 3. Solar Oven Geometry with Reflectors
G: The Gain from Reflectors Where: N = the number of reflectors r = the reflectivity of the aluminum foil on the reflectors (see Table 3, page 13) M = the length of the reflectors L = the length of the oven window α = the angle by which light from the reflectors enters the window (when the window is normal to solar radiation) Equation 28, page 17
G: The Gain from Reflectors Solving for α, we can obtain the more useful lid angle, Ω: Table 4. Reflector Settings for an Oven with Θs + β = 90
Solar Oven Resource Dr. Tharp’s video from Fall, 2010: http://www2.engr.arizona.edu/~tharp/102/index.html • Excellent overview of solar oven modeling and equations • Use Internet Explorer – does not work in Firefox
One moment, please • Switching to Effective Presentations topic