Integral Collector Storage

Integral collector storage (ICS)Integral collector storage is a method of storing thermal energy within the collector itself. Although a standard thermal collector has some storage capacity in its piping, ICS employs either oversize piping or large formed rectangular box channels, to increase the stored liquid capacity within the collector. This allows for additional thermal capacity without requiring a separate insulated storage tank

Flat Plate Collectors

Flat plate collectorsFlat-plate collectors, developed by Hottel and Whillier in the 1950s, are the most common type. They consist of (1) a dark flat-plate absorber of solar energy, (2) a transparent cover that allows solar energy to pass through but reduces heat losses, (3) a heat-transport fluid (air, antifreeze or water) to remove heat from the absorber, and (4) a heat insulating backing. 

Evacuated tube collectors

Evacuated tube collectorsMost vacuum tube collectors in use in middle Europe use heat pipes for their core instead of passing liquid directly through them. Direct flow is more popular in China. Evacuated heat pipe tubes (EHPTs) are composed of multiple evacuated glass tubes each containing an absorber plate fused to a heat pipe. The heat from the hot end of the heat pipes is transferred to the transfer fluid (water or an antifreeze mix—typically propylene glycol) of a domestic hot water or hydronic space heating system in a heat exchanger called a "manifold". The manifold is wrapped in insulation and covered by a sheet metal or plastic case to protect it from the elements.

Solar Air Heat Collector

Solar air heat collectors heat air directly, almost always for space heating. They are also used for pre-heating make-up air in commercial and industrial HVACs stems. They fall into two categories: Glazed and Unglazed.Glazed systems have a transparent top sheet as well as insulated side and back panels to minimize heat loss to ambient air. The absorber plates in modern panels can have an absorptivity of more than 93%. Air typically passes along the front or back of the absorber plate while scrubbing heat directly from it. Heated air can then be distributed directly for applications such as space heating and drying or may be stored for later use.

Solar Bowl

Solar bowlis a type of solar thermal collector that operates similarly to a parabolic dish, but instead of using a tracking parabolic mirror with a fixed receiver, it has a fixed spherical mirror with a tracking receiver. This reduces its efficiency but makes it cheaper to build and operate. Designers call it a fixed mirror distributed focus solar power system. The main reason for its development was to eliminate the cost of moving a large mirror to track the sun as with parabolic dish systems

Types of Solar Collectors for

Electricity Generation

Parabolic Trough

This type of collector is generally used in solar power plants. A trough-shaped parabolic reflector is used to concentrate sunlight on an insulated tube (Dewar tube) or heat pipe, placed at the focal point, containing coolant which transfers heat from the collectors to the boilers in the power station.

Parabolic trough

Parabolic Dish

Parabolic dishWith a parabolic dish collector, one or more parabolic dishes concentrate solar energy at a single focal point, — similar to the way a reflecting telescope focuses starlight, or a dish antenna focuses radio waves. This geometry may be used in solar furnaces and solar power plants

Solar Tower

Concentrated solar power (also called concentrating solar power, concentrated solar thermal, and CSP)-systems use mirrors or lenses to concentrate a large area of sunlight, or solar thermal energy, onto a small area. Electrical power is produced when the concentrated light is converted to heat, which drives a heat engine (usually a steam turbine) connected to an electrical power generator or powers an, experimental as of 2013, thermochemical reaction- is surrounded by tracking mirrors called heliostats. These mirrors align themselves and focus sunlight on the receiver at the top of tower, collected heat is transferred to a power station below.

Advantages of Solar Tower

-Very high temperatures reached. High temperatures are suitable for electricity generation using conventional methods like steam turbine or a direct high temperature chemical reaction such as liquid salt.-Good efficiency. By concentrating sunlight current systems can get better efficiency than simple solar cells.-A larger area can be covered by using relatively inexpensive mirrors rather than using expensive solar cells.-Concentrated light can be redirected to a suitable location via optical fiber cable for such uses as illuminating buildings.-Heat storage for power production during cloudy and overnight conditions can be accomplished, often by underground tank storage of heated fluids. Molten salts have been used to good effect.

Disadvantages of Solar Tower

-Concentrating systems require sun tracking to maintain Sunlight focus at the collector.-Inability to provide power in diffused light conditions. Solar Cells are able to provide some output even if the sky becomes a little bit cloudy, but power output from concentrating systems drop drastically in cloudy conditions as diffused light cannot be concentrated passively.

DarkEnergy

Why is the universe speeding up?In 1998, two teams of astronomers studying distant supernovae made the remarkable discovery that the expansion of the universe is speeding up. Yet, according to Einstein's theory of General Relativity, gravity should lead to a slowing of the expansion. To explain cosmic acceleration, cosmologists are faced with two possibilities: Either 75% of the universe exists in an exotic form, now called dark energy, that exhibits a gravitational force opposite to the attractive gravity of ordinary matter, or General Relativity must be replaced by a new theory of gravity on cosmic scales.The Dark Energy Survey (DES) is designed to probe the origin of the accelerating universe and help uncover the nature of dark energy by measuring the 14-billion-year history of cosmic expansion with high precision. More than 120 scientists from 23 institutions in the United States, Spain, the United Kingdom, Brazil, and Germany are working on the project. This collaboration is building an extremely sensitive 570-Megapixel digital camera, DECam, and will mount it on the Blanco 4-meter telescope at Cerro Tololo Inter-American Observatory high in the Chilean Andes. Starting in Sept. 2012 and continuing for five years, DES will survey a large swath of the southern sky out to vast distances in order to provide new clues to this most fundamental of questions.

Albert Einstein, 1947. Einstein used his "cosmological constant" to help describe a static universe. When he learned the universe was expanding, he discarded it.

Einstein theorized that mass warps the shape of space, creating the force we call gravity.

Einstein theorized that mass warps the shape of space, creating the force we call gravity.

Supernova 1994D in NGC4526

The Corpuscular Theory The Corpuscular Theory The Corpuscular Theory The Corpuscular Theory The Corpuscular Theory

The Corpuscular Theory--- Created in the seventeenth century by Sir Isaac Newton 

--- States that light emitted by luminous objects consist of tiny particles of matter called corpuscles. When corpuscles hit a surface, each partice is reflected. --- Thought that light traveling from air into water will increase the speed, while light entering water will decrease the speed.

The Wave Theory--- Discovered by Christian Huygens, a Dutch scientist, also in the seventeenth century 

--- States that light is emitted in a series of waves that spread out from a light source in all directions. These waves are not affected by gravity. --- Furthermore, he disagreed with Newton and said that light traveling from air to water will decrease the speed, and vice versa. Huygens was proved later to be correct. 

--- 100 years later, Englishman Thomas Young completely disproved the corpuscular theory by showing that light waves can interfere with each other.

The Electromagnetic Theory--- Discovered in the nineteenth century by James Maxwell 

--- Proposed that light waves do not require a medium for transmission. --- Light waves posses electrical and magnetic properties and can travel though a vacuum. Light waves are a part of a larger family of electromagnetic waves and make up the electromagnetic spectrum.

THE QUANTUM THEORY---discovered by  Max Planck, a German scientist in 1990

--- Stated that light waves travel as separate packets of energy called quanta or photons. --- Merged the subjects of the Corpuscular, Wave, and Electromagnetic Theories together.Later, it was proved that the correct and most accurate theory was the Quantum Theory.

Speed of LightThe speed of light is much greater than the speed of sound. 

      Olaus Roemer --- Danish Scientist, 1st method to find the speed of light, used the planets, he calculated the speed of light was 227,000 kilometers per second 

      Albert A. Michelson --- 1926, developed a more modern method to determine the speed of light, used mirrors, calculated the speed of light to be 186,285 miles per second (299,796 kilometers per second) 

The wavelength of any electromagnetic vibration x its frequency = the speed of the electromagnetic vibration 

Scientists have determined that the speed of any electromagnetic vibration = the speed of light (approximate value of the speed of light is 300,000 kilometers per second) 

The speed of an electromagnetic wave is not affected by temperature, but it is affected by the medium through which it travels.

Transmission of LightLight can travel through a vacuum. 

      Opaque Objects --- completely block light and through which you cannot see 

      Transparent Objects --- readily transmit light and through which you can see clearly 

      Translucent Objects --- allow light to pass through partially or that distort the light so that you cannot see through them

Behavior of LightLight travels in a straight line. 

      Pinhole Camera --- the object that is viewed is upside-down 

      Shadow --- the dark space behind an object that is formed when light is blocked by that opaque object 

      Umbra --- the darker central portion of the shadow that receives no light from the source 

      Penumbra --- the lighter shadow that surrounds the umbra and receives some light from outer edges of the light source