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Solar Energy. Solar energy has been an under-achiever. Source: U.S. Department of Energy. http:// symposium2011.serdp-estcp.org/Technical-Sessions/3C. Solar Energy Has A Long History. 2500+ years Passive – take advantage of ambient conditions 250+ years
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Solar energy has been an under-achiever Source: U.S. Department of Energy
Solar Energy Has A Long History • 2500+ years • Passive – take advantage of ambient conditions • 250+ years • Active Loop – capture, store, & deliver thermal energy • 50+ years • Photovoltaics – convert sunlight into electricity • 25+ years • Hybrid Systems - concentrating collectors & others
Passive solar collectors can be as simple as a house designed to take advantage of daylighting.
Passive solar heating recognizes the seasonal position of the sun.
Passive Day Lighting System • tracking dish to collect sunlight • visible spectrum transmitted using fiber optics • packaged like a fluorescent light • commercialization underway by Oak Ridge Lab
How does a photovoltaic cell work? http://science.nasa.gov/headlines/y2002/solarcells.htm
Optimum Mounting Angle • Solar tracking systems improve overall efficiency up to 30% by keeping panels perpendicular to the sun. • A fixed panel set at the same angle as the latitude of the site will receive the maximum annual solar radiation. • If the load demand is high in the winter (northern hemisphere), set the panel tilt at latitude plus 15°. • If the load demand is higher in the summer (northern hemisphere) set the array tilt angle at latitude minus 15°.
Solar Energy Influenced by: • atmospheric conditions • geographic location • time of day • pollution • season
Average sunshine hours (hr/day) Sizing a Photovoltaic Array Electric Loads daily energy requirements (kW-hr)/day Array Size in kW = How much solar energy is available?
Quantifying Home Electric Loads • Search using some of the following terms • Residential • Electric • Calculator • http://www.nhec.com/residential_energycalculators.php • http://www.tampaelectric.com/TEHMEnergySaversCalc.html
Web-Based PV Array Sizing • Combine the power of • Mapping programs • PV sizing algorithms • Satellite-based weather data • Databases of rebates, tax credits, and other incentives • http://www.nrel.gov/eis/imby/
Solar energy challenges • Better methods of energy storage • Cheaper manufacturing methods • Better installation techniques • Higher efficiency
pro’s free, renewable, and non-polluting provides day-lighting, heat, & electricity low maintenance independence con’s more expensive than conventional power energy source fluctuates Is solar energy a viable option? must evaluate case-by-case