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Energy Efficiency

Energy Efficiency

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Energy Efficiency

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Presentation Transcript

  1. Energy Efficiency

  2. Key Questions: How do we heat/cool our homes? How do we get our heat? How does heat transfer? How do we increase energy efficiency? Why increase efficiency?

  3. How do we heat/cool our homes? • Forced Air Heating and Cooling • What? • Air heated/cooled • Distributed through ductwork • How? • Natural Gas/Electricity • Why? • Can be used for heating and cooling • Relatively inexpensive • High Annual Fuel Utilization Efficiency (AFUE) • Efficiency of converting fuel to energy.

  4. Coal Power Plants

  5. Coal Power Plants: Air

  6. Coal Power Plants: Land

  7. Coal Power Plants: Water

  8. Natural Gas: Air

  9. Natural Gas: Land

  10. Natural Gas: Water

  11. How Do We Get Our Heat?

  12. How Does Heat Transfer? • Second Law of Thermodynamics • Heat goes from a warm place to a cold place. • In homes: • When heating, heat is lost to the outside. • Hot objects will cool to room temperature. • When cooling, heat is gained from the outside). • Cool objects will warm to room temperature.

  13. Conduction • Heat is transferred through materials by direct contact (transferred to adjacent molecules). • Ex. Putting a spoon in hot water

  14. Thermal Conductivity Conductors vs. Insulators

  15. Convection • Heat is transferred by mass motion fluids such as air or water. • Ex. Forced air by fan • What happens to particles when you heat them?  • They spread out  less dense. • Hot air rises, cool sinks down and takes it place

  16. Convection

  17. Radiation ? • Heat is transferred by electromagnetic waves. • The source heats an object but not the median in between. • Ex. The Sun heating a house.

  18. Radiation Absorption vs. Emission

  19. How Do We Increase Energy Efficiency?