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
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
        devices on roofs
        or in fields
    •   Typically a black
        panel or plate
o   Used to heat
        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
o   Benefits
    •   No air pollution
    •   No contribution to global warming or acid
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
    •   Renewable when used
        no faster than it can
        be produced
o   Can convert to biogas
    or liquids
    •   Ethanol and methanol
        Advantages and Disadvantages of
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
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
o   New wind turbines harness
    wind efficiently
                    Wind Energy
o   Most profitable in rural areas with constant
o   Few environmental problems
    •   Kills birds and bats
o   No waste- clean
    source of energy
o   Biggest
    •   Cost
    •   Public resistance
        Indirect Solar
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%)
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
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
                  o   From Hydrothermal
                      Reservoirs (left)
                      •   Created by volcanoes
                      •   Reservoirs used
                          directly for heat or
                          to generate
               Geothermal Energy

o   From hot, dry rock
o   Geothermal heat
    •   Use difference in
        temperature between
        surface and
    •   Great for heating
    •   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
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
    •   Highly volatile (requires special storage)
    •   Relatively inefficient
Hydrogen as a Fuel Source-
                 Hydrogen Fuel Cell
o   Fuel cell
    •   Device that directly converts chemical energy into
    •   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
    •   Hydrogen is not
        yet readily
        available as a fuel
o   Batteries in cells
    phones or laptops
Energy Consumption Trends and
      Energy Efficient Technologies

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

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
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