Solar Energy

1. Photovoltaic Systems: Convert sunlight directly to electricity.
a. Solar cells absorb packets of sunlight called photons
b. The energy carried by the photons is converted to electricity
c. Photovoltaic Cells are used for producing electricity for many off-grid applications and for consumer items such as calculators and watches.
d. National Center for Photovoltaics:http://www.nrel.gov/ncpv/
e. DOE’s Photovoltaics Program http://www.eere.energy.gov/pv/
f. Flash Animation on how Photovoltaic Cell Works: http://www.eere.energy.gov/pv/video.html

2. Concentrating Solar Energy: Sunlight heats water to a boil and steam rotates a turbine attached to the generator that produces electricity
a. Three types of systems are Parabolic-Trough, dish/engine, and power tower
b. U.S. Departments of Energy’s Sun Lab:http://www.eere.energy.gov/sunlab/

3. Passive Solar: Buildings are designed to be easily heated and cooled
a. In the northern hemisphere the south side of a building receives the most sunlight because the winter sun rises in southeast and sets in southwest
b. Large south facing windows allow sunlight to enter building
c. Interior floors and walls absorb and store sun’s heat, releasing it slowly at night when heating is needed
d. NREL research in passive solar technologies from its High Performance Buildings Research Initiative. http://www.nrel.gov/buildings/highperformance/

4. Solar Hot Water: Sunlight is used to heat water or another liquid that is circulated throughout a building for use as heating source
a. Flat Plate Collectors, thin boxes with a transparent top and black heat absorbing bottom are placed on southern facing roofs
b. Water in tubes inside the collector are heated
c. Two types of systems – Active and Passive
d. Active Systems use pumps requiring an external power source to move liquid between collector and storage tank
e. Passive systems use gravity and water’s tendency to circulate as heated so do not require an external power source
f. U.S. Department of Energy’s Solar Buildings Program: http://www.eere.energy.gov/solarbuildings/

5. Solar Process Heating: Techniques used for heating and cooling large buildings using solar energy
a. Ventilation Air Preheating: Large black panels are installed on the exteriors of building and air passes through panels into an enclosed area
b. Air is heated because black panels absorb heat and fans at the top of the enclosure blow in warm, rising air
c. Energy from solar panels used to create electricity to power cooling devices
d. Find out about NREL solar technologies research for nonresidential buildings from its Advanced Desiccant Cooling & Dehumidification Program (http://www.nrel.gov/desiccantcool/) and also see the U.S. Department of Energy's (DOE) Solar Buildings Program. (http://www.eere.energy.gov/solarbuildings/)
e. DOE also has the following reference briefs: Solar Industrial Process Heat (http://www.eere.energy.gov/solarbuildings/) and Active Solar Cooling and Refrigeration. (http://www.eere.energy.gov/consumerinfo/refbriefs/ac2.html)
f. For more information, you might want to see Advanced Buildings Technologies and Practices. (http://www.advancedbuildings.org/)

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