1. Solar Energy

2. The Sun Mass ~ 2 x 1030 kg Diameter ~ 1 390 000 km
Surface temp ~ 6000 C
Power output ~ 3.8 x1026 W

3. How much of this power is available to us?
Distance from Earth-Sun = 1.5 x 1011 m.
Power received = Power of Sun
4πd2
This is a maximum power per square metre and although the atmosphere and Earth’s tilt diminishes some of this, there is still loads available.

4. Solar Cells Sometimes “photocells.” Made from Silicon
Light energy absorbed
Electrons freed from
Silicon crystals
Direct current

5. Pros and cons Pros Little maintenance except for keeping surface clean
Remote locations
Renewable source
Strong, zero emissions.
Cons
Not terribly efficient
Variable output according to season, latitude and cloud cover plus if dark… power = 0.

6. Solar cells are designed to work over quite a narrow band of wavelengths

7. Solar heating Curved shape means that maximum amount of heat
energy reaches
the pan!
Sizzlin’!

8. Passive solar heating can warm water and lower energy bills