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Chapter 13 Renewable Energy and Conservation

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Chapter 13 Renewable Energy and Conservation Powered By Docstoc
					Chapter 13
Renewable Energy and Conservation
            Overview of Chapter 13
o   Direct Solar Energy
    •   Heating Buildings and Water
    •   Solar Thermal Electric Generation
    •   Photovoltaic Solar Cells
o   Indirect Solar Energy
    •   Biomass Energy
    •   Wind Energy
    •   Hydropower
o   Other Renewable Energy Sources
    •   Geothermal Energy
    •   Tidal Energy
o   High and Low Technology Energy Solution
    •   Hydrogen and Fuel Cells
o   Energy Efficiency
            Direct Solar Energy
o   Varies with latitude, season, time of day,
    and cloud cover
        Heating Buildings and Water

o   Passive solar energy
    •   system of putting the sun’s energy to use
        without requiring mechanical devices to
        distribute the collected heat
o   Certain design features can enhance
    passive solar energy’s heating potential
    •   South facing windows (in N. hemisphere)
    •   Well insulated buildings
    •   Attic vents
    •   Overhangs and solar sunspaces
Solar sunspace

o   Utilizes passive
    solar energy to
    heat and cool
    homes
o   Can be added to
    existing homes
        Heating Buildings and Water
o   Active Solar Energy
    •   System of collecting and absorbing the sun’s
        energy, and using pumps or fans distribute the
        collected heat
o   Most common
    •   Series of
        collection
        devices on roofs
        or in fields
    •   Typically a black
        panel or plate
o   Used to heat
    water
        Heating Buildings and Water
o   Solar Thermal Electric Generation
    •   Means of producing electricity in which the
        sun’s energy is concentrated by mirrors or
        lenses to either heat a fluid filled pipe or drive
        a Stirling engine
o   More efficient than other solar
    technologies
o   Benefits
    •   No air pollution
    •   No contribution to global warming or acid
        precipitation
Solar Thermal Electric Generation
         Photovoltaic Solar Cells

o   Thin cells are treated with certain metals
    so that they generate electricity when
    they absorb solar energy
                        o Convert sunlight
                          directly into energy
                        o No pollution and
                          minimal maintenance
                        o Used on any scale
                         •   Lighted road signs
                         •   Entire buildings
            Photovoltaic Solar Cells
o   Can be incorporated into building materials
    •   Roofing shingles
    •   Tile
    •   Window glass
Cost of Electrical Power Plants
                Indirect Solar Energy
o   Biomass
    •   Plant materials used as fuel
         •   Ex: wood, crop wastes, sawdust, and animal wastes
    •   Contains energy from sun via photosynthesizing
        plants
    •   Renewable when used
        no faster than it can
        be produced
o   Can convert to biogas
    or liquids
    •   Ethanol and methanol
        Advantages and Disadvantages of
                    Biomass
o   Advantages
    •   Reduces dependence on fossil fuels
    •   Often uses waste materials
    •   If trees are planted at same rate biomass is
        combusted, no net increase in atmospheric CO2
o   Disadvantages
    •   Requires land, water and energy
    •   Can lead to
         •   Deforestation
         •   Desertification
         •   Soil erosion
         Indirect Solar
            Energy
o   Wind Energy
    •   Electric or mechanical energy
        obtained from surface air
        currents caused by solar
        warming of air
    •   World’s fastest growing
        source of energy
o   Wind results from sun
    warming the atmosphere
    •   Varies in direction and
        magnitude
o   New wind turbines harness
    wind efficiently
                    Wind Energy
o   Most profitable in rural areas with constant
    wind
o   Few environmental problems
    •   Kills birds and bats
o   No waste- clean
    source of energy
o   Biggest
    constraints
    •   Cost
    •   Public resistance
        Indirect Solar
           Energy
o   Hydropower
    •   Form of renewable
        energy reliant on
        flowing or falling water
        to generate mechanical
        energy or electricity
o   Sun’s energy drive
    hydrologic cycle
o   Most efficient energy
    source (90%)
                    Hydropower
o   Generates 19% of world’s energy
o   Traditional hydropower
    •   Only suited for large dams
o   New technology
    •   May be able to utilize low flow waterways
o   Problems with Dams
    •   Changes natural flow of rivers
    •   Disrupts migratory fish patterns
    •   Potential dam breaks
        Other Indirect Solar Energy

o   Ocean waves
    •   Produced by winds
    •   Has potential to turn a turbine- and create
        electricity
o   Ocean Temperature Gradients
    •   Use difference in temperature of surface and
        deep water to create electricity
Other Renewable
                  o   Geothermal Energy
Energy Sources
                      •   Energy from the
                          Earth’s interior for
                          either space heating
                          or generation of
                          electricity
                  o   From Hydrothermal
                      Reservoirs (left)
                      •   Created by volcanoes
                      •   Reservoirs used
                          directly for heat or
                          to generate
                          electricity
               Geothermal Energy

o   From hot, dry rock
o   Geothermal heat
    pumps
    •   Use difference in
        temperature between
        surface and
        subsurface
    •   Great for heating
        buildings
    •   Expensive installation
    Other Renewable Energy Sources

o   Tidal Energy
    •   Form of renewable energy that relies of the
        ebb and flow of the tides to generate
        electricity
o   Typical difference between high and low
    tide is 1-2 ft
    •   Narrow bays may have greater variation
o   Energy can be captured with
    •   A dam across the bay
    •   A turbine similar to a wind turbine
             Hydrogen as a Fuel Source

o   Advantages to Hydrogen as a fuel source
    •   Very high energy density
    •   Can be produced from any electrical source
         •   Electrolysis (see illustration on next slide)
    •   No greenhouse gases and few other pollutants
    •   Can be use in vehicles
o   Disadvantages to Hydrogen as a fuel
    source
    •   Highly volatile (requires special storage)
    •   Relatively inefficient
Hydrogen as a Fuel Source-
      Electrolysis
                 Hydrogen Fuel Cell
o   Fuel cell
    •   Device that directly converts chemical energy into
        electricity
    •   Requires
        hydrogen from a
        tank and oxygen
        from the air
o   Similar to a
    battery, only the
    reactants are
    supplied from
    outside source
    Future Applications of Fuel Cells

o   Vehicles
    •   Not yet commonly
        available
    •   Hydrogen is not
        yet readily
        available as a fuel
        source
o   Batteries in cells
    phones or laptops
Energy Consumption Trends and
          Economics
      Energy Efficient Technologies

o   Compact Fluorescent light bulbs
o   Condensing furnaces
o   Super-insulated
    buildings (right)
o   Energy efficient
    appliances
o   Automobiles
o   Aircraft technology
                Cogeneration

o   Production of two useful forms of energy
    from the same fuel
Energy Savings in Commercial Buildings
Saving Energy at Home

				
Lingjuan Ma Lingjuan Ma MS
About work for China Compulsory Certification. Some of the documents come from Internet, if you hold the copyright please contact me by huangcaijin@sohu.com