RenewableRenewable Energy: Energy: Solar EnergySolar Energy

Types of Renewable EnergyTypes of Renewable Energy• Solar Solar • WaterWater• WindWind• BiomassBiomass

–burningburning–conversion to liquid fuelsconversion to liquid fuels

• Geothermal Geothermal • Solar-HydrogenSolar-Hydrogen

Current Sources of EnergyCurrent Sources of Energy

Direct Solar EnergyDirect Solar Energy

• Used toUsed to– Heat houses and buildingsHeat houses and buildings

– Heat waterHeat water

– Create high temperature heatCreate high temperature heat

– Create electricityCreate electricity

• Methods of creating electricityMethods of creating electricity

– Biomass EnergyBiomass Energy– Wind EnergyWind Energy– HydropowerHydropower– OTECOTEC– Waves & TidesWaves & Tides

Indirect Solar EnergyIndirect Solar Energy

Passive Solar HeatingPassive Solar Heating

• Uses special materials, design Uses special materials, design orientation and space to utilize orientation and space to utilize

solar energy.solar energy.• Considers exposure direction, Considers exposure direction,

windows, building materials, windows, building materials, eaveseaves

• Requires NO input of energyRequires NO input of energy• East CoastEast Coast

Trombe WallTrombe Wall• Passive Passive

heating system heating system where a where a massive wall is massive wall is built behind a built behind a window window exposed to the exposed to the sun that will sun that will retain and re-retain and re-emit solar heat.emit solar heat.

Extended EavesExtended Eaves

• Passive heating that blocks the Passive heating that blocks the summer sunsummer sun

Water HeatingWater Heating• Flat box with glass on top, black on the Flat box with glass on top, black on the

bottom, water tubes in middlebottom, water tubes in middle–Hot water coming Hot water coming

out of tubes is placed out of tubes is placed in top of water tankin top of water tank

–Cooler water from bottom Cooler water from bottom returned to returned to collectorcollector

Passive Solar HeatingPassive Solar Heating

• Solar Solar CookersCookers–metal lined metal lined

box and box and mirrors mirrors focus solar focus solar energy to energy to cook foodcook food

Fresh Water Solar PondsFresh Water Solar Ponds• Passive: Holes are

dug and lined with black plastic.–Water heats up,

but heat is prevented from escaping with insulating panels.

• Doesn’t require expensive storage

Active Solar HeatingActive Solar Heating• Input of Input of

energy to gain energy to gain full benefits full benefits from solar from solar heating.heating.

• Ex: using Ex: using pumps or fans pumps or fans to utilize sun to utilize sun energyenergy

PV Cells: Active Heating• Photovoltaic cells• When photons from

sun hit a thin wafer of metal, a small elec. current is produced

• Many cells must be linked to prod usable energy

• Used in remote areas, calculators, watches

Solar Cell Backpack Anyone?Solar Cell Backpack Anyone?

It will charge It will charge your iPodyour iPod

PV Solar CellsPV Solar Cells

• Pros: used in remote areas, no greenhouse gas emissions emitted, noiseless

• Cons: initial cost, much land is needed, many must be used to be efficient, wears down over time, breaks easily, materials aren’t recyclable.

Grid vs Stand Alone PV CellsGrid vs Stand Alone PV Cells• Grid: PV Cells Grid: PV Cells

linked together; can linked together; can send power back to send power back to city’s lines. Can get city’s lines. Can get $$$$

• Stand Alone: PV cell Stand Alone: PV cell by itself (not by itself (not connected to city’s connected to city’s power). Needs a power). Needs a battery to store battery to store energy when sun energy when sun not available. (Hg)not available. (Hg)

Active HeatingActive Heating• Solar TowersSolar Towers

–many mirrors are used to focus many mirrors are used to focus solar energy solar energy heats oil heats oil turbineturbine

Solar-Hydrogen Energy- TheorySolar-Hydrogen Energy- Theory• H gas used for energy in 2 ways:

–burned directly - since no carbon, it burns cleanly

–combined with oxygen gas to produce water (fuel cells)

• Problems:–H2 gas is costly to make through

chemical rxns

Fuel CellFuel CellDevice that takes H and O to make

electricity. Byproduct = water & heat.

Fuel Cell Car

Fuel CellsFuel Cells

• Pros: 1. No CO2 emitted2. H can be produced from water3. High efficiency

• Cons: 1. H is very flammable2. H not found alone in nature3. Energy is needed to produce fuel (from

water)4. No distribution system in place.