Solar Water Heaters

1. Solar Water Heaters

2. Objectives • Define absorb, reflect, solar collector • Compare the effect of black and white collectors in solar water heaters • Compare the temperature change in covered and uncovered solar heaters

3. How can we catch the energy we receive from the Sun and put it to work for us?

4. Solar Collector Any material or object placed in the sun to absorb solar energy for transfer to water or air

5. Absorb – to take up, soak in, or capture • Reflect – to bounce back.

8. Sunlight

10. reflected (bounce back)absorbed ( soak in)

11. When light is absorbed, kinetic energy increases. • When kinetic energy increases, temperature usually increases.

13. How did the black collector make water hotter? • Black containers absorb energy from the sun. As they absorb energy, they get hot.

14. How did the covered container make water hotter? • A covered container keeps air from carrying heat away.

15. How did energy absorbed by black plastic heat the water? • Energy absorbed by the black plastic transfers to the water by contact (conduction).

16. What is the best design for a solar water heater? • It should be black to absorb the sun’s energy, contain water that is in contact with the collector, and have a cover to keep air from cooling the water.