1.  This presentation deals with solar water heaters.  There are two categories (passive, active)  There are two common types (conventional, vacuum tubes); uncommon - reflective  Any of these may operate on one of two principles : direct or heat exchange. objective

2. A B C

3.  Objective 4.6 b : Students should be able to relate the principle of thermal energy transfer to the design of devices – solar water heater.  Our Focus : Conventional passive direct.  Pre-requisite : (a) Thermal transfer ( b) Absorption of radiation lesson Conduction (solids) Convection (fluids) Radiation (vacuum) Flat black objects

4. Passive : Outlet from collector is lower than inlet of hot water inlet to storage tank. No pump required. Active : Outlet from collector is higher than hot water inlet to storage tank. Pump required. More passive More active

5. To active slide

7. More conventional More vacuum tubes

8. To vacuum tubes

13. A : How heat reaches Earth from Sun B : Why the glass? C : Copper tubes with heat sinks, painted flat black. D1 – D2 : Collector slanted with outlet at upper end and inlet at lower end. E : Insulated storage tank. F : Hot water outlet from tank to house at top of tank. critical thinking

14. State two correct features of the above diagram and one bad feature. Please pause the video now, think about this for a few minutes, and then continue to find out how your answers compare with mine.

15. questions Please pause the video now, think about this for a few minutes, and then continue to find out how your answers compare with mine.

16.  1: By what method does heat from the sun reach Earth?  Radiation  2. What effect does the glass of the collector produce?  Greenhouse effect  3. Why is everything in the collector painted flat back?  Flat black – best absorber of infrared radiation  4. What is the process by which heat is transferred through the walls of the copper tubing?  Conduction More questions

17.  5. In the passive system, by what process does the water flow through the tubes and into the storage tank?  Convection  6. Why would 4 mm PVC (plastic) be a better material for the inside of the storage tank than 1 mm steel (assuming that both have the required strength)?  4 mm PVC is a better insulator.  7. Why is the hot water pipe to the home connected to the top of the storage tank?  The hot water, being less dense, floats at the top. passive resources

18.  http://www.energysavers.gov/your_home/water_heating/index.cfm/mytopic=12850 http://www.energysavers.gov/your_home/water_heating/index.cfm/mytopic=12850  http://www.builditsolar.com/Projects/WaterHeating/water_heating.htm http://www.builditsolar.com/Projects/WaterHeating/water_heating.htm  http://chinasolarwaterheater.blog.com/working-principle-of-solar-water-heater.html/ http://chinasolarwaterheater.blog.com/working-principle-of-solar-water-heater.html/  http://www.motherearthnews.com/Renewable-Energy/1979-09-01/A-Homemade-Solar-Water- Heater.aspx http://www.motherearthnews.com/Renewable-Energy/1979-09-01/A-Homemade-Solar-Water- Heater.aspx  http://www.youtube.com/watch?v=oBpKPes3cEE http://www.youtube.com/watch?v=oBpKPes3cEE passive Conventional passive Please visit http://csecphysics.weebly.com to view this presentation and to download a copy of the accompanying brochure or this PowerPoint presentation. To take the quiz, you will need an access code (available to my students).http://csecphysics.weebly.com

19. To active slide Reduce your carbon footprint Save on electricity bill