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Solar Facts
What's the difference between solar water heating and solar electricity?
- Solar Photovoltaic(PV for short)
- Converts sunlight
into electricity
- 18-20% efficient(20% of the energy is converted to electricity)
- 15,000 megawatts worldwide
Solar Water Heating
- Directly heats fluid by solar heat
- Stores heat in a large tank for day/night use
- 60% thermal efficiency(system efficiency is 80%+ )
- 450,000 megawatts worldwide
The $5,800 solar water heater on the left produces the same amount of energy as the $30,000 PV system on the right
Solar water heater Solar PV panels
The Worldwide emergence of solar thermal water heating
- Woldwide, Solar thermal produces 30 times as much
energy as solar PV at a fraction of the cost.
- Over 90% of the homes in Israel and Cyprus use solar
water heating due to high energy costs
- As of 2009, close to 30,000 solar water heaters are installed every year in the U.S.
- China has over 27 million rooftop solar water heaters.
- Millions installed worldwide annually, Very common in Germany,
Austria, the Middle East, the Bahamas, anywhere energy prices are high.
- In the U.S., they are most common in Florida,
California, and Hawaii.
- Because of their tremendous efficiency, solar water heating is now required by code in all new homes in:
- Hawaii requires solar water heating in all new construction as of 2008.
- Austin, TX requires a solar water heater or a heat pump to be installed in existing homes with an electric water heater if the homeowner wishes to receive a solar PV rebate.
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