UAU212F Spring 2012 Throstur Thorsteinsson ([email protected]) 1 Sustainable Energy Options UAU212F SOLAR ENERGY Throstur Thorsteinsson [email protected]2012 NASA's Solar Dynamics Observatory snapped this view of the powerful X1.7-class solar flare that erupted at 1:37 p.m. EST on Jan. 27, 2012. http://www.space.com/14388-massive-flare-tops-sun-active-week.html - video Solar energy - overview ⇨ Solar energy is intercepted by the Earth is about 10,000 times greater than the rate at which humankind consumes energy ⇨ The world installed capacity of solar thermal systems at the end of 2009 has been estimated to be 180 GWth. ⇨ As of the end of 2009, the installed capacity for PV power production was about 22 GW Solar power potential - technical For the minimum estimates, minimum annual clear-sky irradiance, sky clearance and available land used for installation of solar collectors are assumed For the maximum estimates, maximum annual clear-sky irradiance and sky clearance are adopted with an assumption of maximum available land used. Solar power potential Solar power ⇨ Use of Solar energy to heat houses, water or to produce electricity - issues: ⇨ Solar energy is subject to daily and seasonal variations – which necessitates a backup system driven by other fuels. ⇨ Is subject to geographical variation – the availability of solar energy depends on latitude. Areas near the equator get more solar energy than e.g. Canada. ⇨ Weather conditions: cannot collect solar energy if it is cloudy, and the solar irradiance is diffuse requiring significant land space. ⇨ Siting option: available land for large scale use of solar power is limited by the current use of land – e.g. urban areas, agricultural areas etc.
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Sustainable Energy Options - University of Iceland · Sustainable Energy Options UAU212F SOLAR ENERGY Throstur Thorsteinsson ... ⇨ As of the end of 2009, the installed capacity
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⇨ Passive ⇨ Architectural designs. Capture solar energy and use to
heat or cool houses e.g. ⇨ Sunrooms
⇨ Solar cookers
⇨ Block high angle sunlight, but allow winter sunlight
through
⇨ Active ⇨ Solar domestic hot water heater system
⇨ Solar space heating- either water or air
Passive systems
⇨ Captures sunlight within
a structure and converts
to heat ⇨ Efficient windows
⇨ Thermal mass to absorb heat
(capacity to store heat)
⇨ Direct or indirect gain
Solar collector
Unglazed Solar Collectors are primarily used to pre-heat make-up ventilation air in commercial, industrial and institutional buildings with a high ventilation load.
Active system
⇨ Solar domestic hot water
heater system:
⇨ Consists of three
components: i. solar collector panel
ii. storage tank
iii. circulator system to transfer
the heat from the tank to the
use area.
⇨ Pump driven by electrical
power - thus active
High T power system
⇨ All rely on four basic elements: 1. collector/concentrator – captures and concentrates the
solar energy which is then transported to a....
2. receiver, absorbs the sunlight transferring the heat
energy to a working fluid e.g. steam
3. transport/storage passes the fluid from the receiver to
the power generation system. – and may be stored for
later use.
4. power conversion from AC to DC electricity.
Types
A) Parabolic trough: Solar farm. Consists of long
parallel rows of identical concentrator modules
concentrates solar radiation.
B) Central receiver/power tower: Huge arrays of
computer controlled mirrors called heliostats track
the sun and focus sunlight onto a fixed receiver
which is located on the top of a tower.
C) Parabolic dishes: Parabolic shaped focus
concentrator in the form of a dish that reflects solar
radiation onto a receiver mounted at the focal point.
Solar collectors capture and concentrate sunlight to heat a synthetic oil called therminol, which then heats water to create steam. The steam is piped to an onsite turbine-generator to produce electricity, which is then transmitted over power lines. On cloudy days, the plant has a supplementary natural gas boiler.
Photovoltaics is the direct conversion of light into electricity at the atomic level. Some materials exhibit a property known as the photoelectric effect that causes them to absorb photons of light and release electrons. When these free electrons are captured, an electric current results that can be used as electricity.
As light hits the solar panels, the solar radiation is converted into direct current electricity (DC). The direct current flows from the panels and is converted into alternating current (AC) used by local electric utilities. Finally, the electricity travels through transformers, and the voltage is boosted for delivery onto the transmission lines so local electric utilities can distribute the electricity to homes and businesses.
Cost of PV Photovoltaic costs (1985 Yen per Watt installed) as a function of cumulative installed capacity (in MW), Japan 1976–1995. Data source: [Watanabe, 1995] and Watanabe, 1997.
Energy Economics Volume 20, Issues 5–6, 1 December 1998, Pages 495–512