Solar-Derived Energy Resources - Direct Solar Power
- Created by: Megan Cameron
- Created on: 18-02-13 19:03
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- Solar-Derived Energy Resources - Direct Solar Power
- Photothermal systems
- Sunlight can be used to heat buildings and water.
- Passive solar heating is the heating of a building by absorbing sunlight without the use of additional equipment.
- Building design can increase passive solar gains by having large windows or a conservatory facing in the direction from which most sunlight will be absorbed.
- Hot water can be produced in solar panels, which are usually mounted on roofs. Their efficiency can be increased by careful orientation and good design.
- Photovoltaic systems
- Sunlight absorbed by the surface layer of photovoltaic cells displaces electrons that can be used to drive electrical appliances.
- When they were first developed, photovoltaic cells were very expensive but mass production has reduced costs.
- Photovoltaic schemes that feed electricity into the mains electricity grid are becoming more common, especially in countries with a sunny climate.
- The output of the cells can be increased with heliostats that turn the panels so that they always face the Sun
- The solar insolation that reaches the Earth's surface has a low energy density and its intensity fluctuates in daily and seasonal cycles.
- The angle of incidence also changes in daily and seasonal cycles so there is no single optimum position for a solar panel to harness solar power.
- This can be solved by 'tracking' the sun with a heliostat so the receiver is always at the optimum angle to receive sunlight.
- Clouds, smoke and dust can reduce the intensity of the insolation. They can also scatter the light.
- The angle of incidence also changes in daily and seasonal cycles so there is no single optimum position for a solar panel to harness solar power.
- Environmental Impacts
- Electricity may be used to pump water in photothermal systems or to rotate heliostats
- Maintenance will result in some transport impacts
- Extraction and processing of the materials used in construction, such as glass, copper, aluminium and plastics
- No habitat loss during installation as usually put on buildings
- Photothermal systems
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