Parabolic trough
The sunlight which enters the mirror parallel to its plane of symmetry is focused along the focal line, where objects are positioned that are intended to be heated.
This tracking method approaches theoretical efficiencies at the spring and fall equinoxes with less accurate focusing of the light at other times during the year.
Due to these sources of error, seasonally adjusted parabolic troughs are generally designed with a lower concentration acceptance product.
[10] In 2009, scientists at the National Renewable Energy Laboratory (NREL) and SkyFuel teamed to develop large curved sheets of metal that have the potential to be 30% less expensive than today's best collectors of concentrated solar power by replacing glass-based models with a silver polymer sheet that has the same performance as the heavy glass mirrors, but at a much lower cost and weight.
The glasshouse creates a protected environment to withstand the elements that can increase the reliability and efficiency of the solar thermal system.
Sheltering the mirrors from the wind allows them to achieve higher temperatures and prevents dust from building up as a result from exposure to humidity.
In November 2017, GlassPoint announced a partnership with Aera Energy that would bring parabolic troughs to the South Belridge Oil Field, near Bakersfield, California.
He, along with his technical advisor A. S. E. Ackermann and British physicist Sir Charles Vernon Boys,[citation needed] developed an improved system using mirrors to reflect solar energy upon collector boxes, increasing heating capacity to the extent that water could now be used instead of ether.
Shuman's plant used parabolic troughs to power a 45–52 kilowatt (60–70 hp) engine that pumped more than 22,000 litres of water per minute from the Nile River to adjacent cotton fields.
[16] In 1916 Shuman was quoted in the media advocating solar energy's utilization, saying: We have proved the commercial profit of sun power in the tropics and have more particularly proved that after our stores of oil and coal are exhausted the human race can receive unlimited power from the rays of the sun.Commercial plants using parabolic troughs may use thermal storage at night while some are hybrids and support natural gas as a secondary fuel source.
In the United States the amount of fossil fuel used in order for the plant to qualify as a renewable energy source is limited to a maximum 27% of electricity production.
[citation needed] Because they include cooling stations, condensers, accumulators and other things besides the actual solar collectors, the power generated per square meter of area varies enormously.
