Solar technologies

Solar technologies are broadly characterized as either passive solar or active solar depending on the way they capture, convert and distribute solar energy. Active solar techniques include the use of photovoltaic panels and solar thermal collectors to harness the energy. Passive solar techniques include orienting a building to the Sun, selecting materials with favorable thermal mass or light dispersing properties, and designing spaces that naturally circulate air.

Solar power

Solar powered electrical generation relies on heat engines and photovoltaics. Solar energy's uses are limited only by human ingenuity. A partial list of solar applications includes space heating and cooling through solar architecture, potable water via distillation and disinfection, daylighting, solar hot water, solar cooking, and high temperature process heat for industrial purposes.To harvest the solar energy, the most common way is to use solar panels.

Solar energy

Solar energy, radiant light and heat from the sun, has been harnessed by humans since ancient times using a range of ever-evolving technologies. Solar radiation, along with secondary solar-powered resources such as wind and wave power, hydroelectricity and biomass, account for most of the available renewable energy on earth. Only a minuscule fraction of the available solar energy is used.
 

The Sun & Energy

Friday, September 24, 2010

The sun is a star.  It is the largest object in our solar system and one of the larger stars in our galaxy.  The source of energy in the Sun is at its core where hydrogen is converted to helium in a thermonuclear reaction.  This energy travels from the core to the surface of the Sun and is released into space primarily as light.  The energy that comes to the Earth is in 2 main forms, heat and light.

Every hour, enough sunlight energy reaches the Earth to meet the world’s energy demand for a whole year.

--- U.S. Department of Energy ---

The amount of energy from the Sun that reaches the Earth annually is 4 x 1018 Joules.***

4 x 1018 Joules/ Year ÷ 365 Days/ Year = 1 x 1016 Joules/ Day
1 x 1016 Joules/ Day ÷ 24 Hours/ Day = 4 x 1014 Joules/ Hour
The amount of energy consumed annually by the world's population is about 3 x 1014 Joules.

Speed of Light Energy from the Sun to Earth.

The earth is the third planet from the sun at a distance of about 93,000,000 (93 million) miles.  If you could pitch a fast baseball to the sun at 100 miles per hour (mph) it would take the ball over 100 years to get there.  On the other hand, it only takes light energy 8½ minutes to reach the earth from the surface of the sun, traveling at the speed of light of course.

Pitching a Baseball at 100 mph to the Sun***

93,000,000 miles ÷ 100 miles/ hour
= 930,000 hours to reach the Sun.;
930,000 hours ÷ 24 hours/ day
= 38,750 days to reach the Sun;
38,750 days ÷ 365 days per year
= 106.16 years to reach the Sun.

Light Energy traveling to Earth***

The speed of light is equal to about 11,000,000 (11 million) miles/ minute. 
93,000,000 miles ÷ 11,000,000 miles/ minute
= 8.45 minutes for light  to travel from the Sun to Earth.
***Calculations are rounded for simplicity.
Posted by Rahul at 6:45 AM

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