16.3Jenna Popik, Melanie Schuster, & Alyssa Pugely

Concept 16-3

Passive and active solar heating system can heat water and buildings effectively, and the costs of

using directly sunlight to produce high-temperature heat and electricity are coming down.

We Waste Huge Amounts of Energy

Four widely used devices that waste energy1. Incandescent light bulb2. Motor vehicle with internal combustion engine3. Nuclear power plant4. Coal-fired power plant

Passive and Active Solar Heating Systems

• Passive Solar Heating Systems: Absorbs and stores heat from the sun directly within a well-insulated structure.

• Active Solar Heating Systems: Captures energy from the sun by pumping a heat-absorbing fluid (such as water or antifreeze solution) through special collectors, usually mounted on a roof or on special racks that face the sun.

White or light-colored roofs reduce overheatingVent allows hot

air to escape in summerSummer

sun Heavy insulation

Winter sun

Superwindow

Super- window

Stone floor and wall for heat storage

PASSIVE

Solar collector White or light-colored roofs reduce overheating

Heat to house (radiators or forced air duct)

PumpHeavy insulation

Super- window

Hot water tank

Heat exchanger

We Can Also Cool Buildings Naturally

• Technologies available– Open windows– Use fans– Superinsulation– Overhangs– Light colored roof– Geothermal pumps

We Can Concentrate Sunlight to Produce High-Temperature Heat and Electricity

Solar thermal systems use different methods to collect and concentrate solar energy in order to

boil water and produce steam for generating electricity. These systems are used mostly in

deserted areas with ample sunlight.

We Can Use Sunlight to Produce Electricity

• We can convert solar energy into electrical energy using photovoltaic cells, commonly called solar cells.

• Solar cells gather sunlight and release electrons into wires

• There are some key problems with using solar energy: – Costly– Needs to be located in a desert area– Fossil fuels are used in production– Contain toxic materials

• Will the cost drop with– Mass production – New designs– Government subsidies and tax breaks

Using Sunlight to Produce Electricity