Recap of Energy Production Hydroelectric Energy Generation Nuclear transport containers Pro’s and Con’s for wind (from London England) Doc Zone special
What are the impacts – environmental, human health, economic…?
ENERGY Efficiency
% Efficiency Comparison of how much useful energy is converted in an energy transformation No energy transformation is 100% efficient, energy is lost in the form of heat, sound…
Units for Energy (E) Energy can be measured with many different units: Joules (J) kiloJoules (kJ) Calories (Cal) kiloWatt hours (kW∙h) Increase Unit Energy Size James Watt James Prescott Joule
Calculation % efficiency = energy out x 100% energy in % efficiency = E out x 100% E in NOTE: units for energy in and out must match
Sample Problem A light uses 230,000J of energy to produce 16,250J of light energy. What is the % efficiency?
Sample Problem 2 A refridgerator uses 450kWh of energy. If there is 497kWh of energy input to run the fridge how efficient is the refridgerator?
Energy efficient electronics are marked with the energy star symbol!