Active solar
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Active solar technologies are employed to convert solar energy into usable heat, cause air-movement for ventilation or cooling, or store heat for future use. Active solar uses electrical or mechanical equipment, such as pumps and fans, to increase the usable heat in a system. Solar energy collection and utilization systems that do not use external energy, like a solar chimney, are classified as passive solar technologies.
Solar hot water systems, except those based on the thermosiphon, use pumps or fans to circulate water, an anti-freeze mixture, or air through solar collectors, and are therefore classified under active solar technology. The solar collectors can be nonconcentrating or 'flat-plate', or of various concentrating designs. Most solar-thermal collectors have fixed mounting, but can have a higher performance if they track the path of the sun through the sky. Solar trackers, used to orient photovoltaic arrays, may be driven by either passive or active technology.
[edit] Solar technology comparison
Active solar-thermal systems, via small pumps or fans, can have significantly higher solar savings fractions than passive solar technologies due to greatly-enhanced heat transfer and transport. An interesting hybrid approach is to use photovoltaics to power pumps or fans. A computer analysis, using thermodynamics and heat transfer software, can be used to compare the performance of various active and passive solar thermal strategies
[edit] See also
- Autonomous building
- Architectural engineering
- Passive solar
- Renewable energy
- Renewable heat
- Solar Power
- Zero energy building
