Renewable_Energy BIO 350

Renewable_Energy BIO 350 - Renewable Energy Options I Solar...

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Renewable Energy Options I Solar Energy A B Biggest drawback is that it is of low quality due to dispersion across the earth’s surface C Options for use 1. a) Passive solar heating i) Uses large windows to collect heat (a) South facing in northern hemisphere, north facing in southern hemisphere (b) Roof overhangs block most summer sunlight but allow winter sunlight to enter the house ii) Heat is stored in stone walls and floors to maintain temperature overnight iii) Entire building is well insulated (a) Can now use recycled fabrics which reduces solid waste iv) Cost is 10-15% higher than conventional home but will save 30-40% on heating costs over the life of the home. v) Net energy ratio: 5.8 b) Active solar heating i) Uses collectors on the roof to absorb heat and store in a liquid that circulates through the house ii) Can be used to heat water, warm air and floors iii) System is more expensive than passive heating systems due to higher maintenance costs iv) Net energy ratio: 3 – 4 2. Concentrated solar energy for producing high-temperature heat or electricity a) Solar-Thermal systems i) Concentrate sunlight with reflectors to heat oil in pipes to high temperatures ii) Heated oil can be used to produce steam for electrical turbines iii) System requires large land areas but the environmental impact is low compared to strip mining coal iv) Effectiveness is limited by cloudy days & night. Current systems supplement with natural gas. v) Net energy ratio: 0.9 b) Photovoltaic (PV) solar cells i) Use a thin, semi-conducting film to directly convert light energy to electricity ii) The newest generation of solar cells are cheaper, more efficient, and have longer lifespans than earlier cells. Some now look like roof shingles
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iii) Overall, installation still costs thousands of dollars, making it one of the more expensive forms of renewable energy (15 - 25 cents per kilowatt-hour). Payments can be incorporated into a mortgage. iv) Could be a significant source of municipal power if industrial & commercial rooftops are used. v) Net energy ratio: 4 – 5 II Wind A A form of indirect solar energy produced by the uneven heating of the earth’s surface and atmosphere. B Like direct solar energy, it is free, but it is also concentrated in certain areas depending on location & topography (coastal areas, islands, mountain tops & passes, open plains, etc.) C Has become one of the fastest growing sources of renewable energy (esp. in Europe) D System is simple 1. Wind pushes propellers elevated on a post. 2.
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This note was uploaded on 06/23/2008 for the course BIO 350 taught by Professor Gillespie during the Spring '08 term at Los Rios Colleges.

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Renewable_Energy BIO 350 - Renewable Energy Options I Solar...

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