Solar Energy Resources

Dish Concentrator for Photovolatic / Thermal (PV/T)

2012-01-04T00:46:00.000-08:00

Photovolatic low efficiency, the researchers tried to make a new breakthrough, by concentrating the sun's rays into one place, so that the received solar radiation energy can be many-fold,

utilization of solar energy is still lacking, while the source of energy from the sun, very abundant, approximately 50% of wasted sunlight absorbed by land and sea, because it recently, various studies conducted to find the optimal utilization of solar energy so that dependence fossil energy can be reduced.

sunlight concentration method is very diverse, one of which is to use dish stirlling, pictured above is a dish that concentrates sunlight onto a central point, and paired PV / T in the middle, PV / T receives 150 times the concentration of sunlight

see the result, nearly 1 kW/m2 can be generated by the concentration of these methods.

Reference

A.Royne,C.J.Dey,D.R.Mills,Cooling o fphotovoltaic cells under concentrated
illumination: acritical review,Solar Energy Materials and Solar Cells86
(2005) 451–483.
L.Zhu,Y.P.Wang,Z.Y.Zhang,Z.L.Fang,Y.Fang,Study the weather-resistance
of dimethyl polysiloxane used in liquid-immersing CPV receivers,Acta
Energiae SolarisSinica31(2010)191–196

Photovoltaic Cell History, Time line of Invention, Type of PV and efficiency

2012-01-03T18:30:00.000-08:00

There are four types of PV are currently being investigated, until in 2005 the maximum efficiency of PV base on Lab. Test is about 40% findings NREL (National Renewable Energy Laboratory) called Spectrolab.
In General, both types of PV are being researched and developed can be divided into four types
1. Multijuction Concentrator (three junction type and two junction type)
2. Crystalline Si Cell (single cell, and thin Multicrystalline Si)
3. Thin Film Technologies (Cu SA2, CdTe, amorphous SRH)
4. Emerging PV (Cell and organic dye cells)

More completely can be seen in the figure below

Source : “Organic-based photovoltaics: toward low-cost power generation”, MRS Bulletin, 30, 2005, p. 10, (www.mrs.org/publications/bulletin)

each type of PV was tested, based on lab results, the resulting efficiency can be seen on the right line, The Si Cell is a product the most are in the market and sold freely, in the Laboratory The Cell is able to produce electricity with efficiency up to 25%, but in fact actually effisiensinya ranged 11-16%, this is because it is influenced a lot of things, such as ambient temperature, altitude and so on.

History of Solar Energy

2008-01-03T21:14:00.000-08:00

Solar energy was used from the 7th Century B.C. to today. We started out concentrating the sun’s heat with glass and mirrors to light fires. Today, we can see that solar energy used in various tool from car, satellite space, calculator, watch, building and mass generated electricity.

7th Century B.C
Magnifying glass used to concentrate sun’s rays to make fire and to burn somethings

3rd Century B.C.
Greeks and Romans use burning mirrors to light torches for religious purposes

20 A.D.
Chinese document use of burning mirrors to light torches.

1st - 4th Century A.D
The Roman bathhouses in the first to fourth centuries A.D. had large south facing windows to let in the sun’s warmth.

1200s A.D
Ancestors of Pueblo people called Anasazi in North America live in south-facing
cliff dwellings that capture the winter sun.

Then the solar Energy Development begin again after 1976, the time line history from those years until now is :

In 1767,
de Saussure set out to determine how effectively glass heat traps could collect the energy of the sun.De Saussure first built a miniature greenhouse five walls thick. He constructed it from five square boxes of glass, decreasing in size from 12 in. on a side by 6 in. high to 4 in. on a side by 2 in. high.

1830’s
Sir John Herschel, the noted astronomer, made a hot box while on an expedition in the 1830’s to the Cape of Good Hope in South Africa. It was a small mahogany container blackened on the inside and covered with glass.(http://solarcooking.org/saussure.htm)

1816
On September 27, 1816, Robert Stirling applied for a patent for his economiser
at the Chancery in Edinburgh, Scotland,a
solar thermal electric technology that concentrates the sun’s thermal energy
in order to produce power.

1839
French scientist Edmond Becquerel,discovered the photovoltaic effect while experimenting with an electrolytic cell made up of two metal electrodes.

1860s
French mathematician August Mouchet proposed an idea for solar-powered steam
engines,These engines became the predecessors of modern parabolic dish collectors.

1876 - PHOTOELECTRIC DREAMS
William Grylls Adams and his student, Richard Evans Day, discovered that an electrical current could be started in selenium solely by exposing it to light, they felt confident that they had discovered something completely new.

1880
Samuel P. Langley, invents the bolometer, which is used to measure light from
the faintest stars and the sun’s heat rays.

1883
Charles Fritts, an American inventor, described the first solar cells made from selenium wafers

1887
Heinrich Hertz discovered that ultraviolet light altered the lowest voltage ca-
pable of causing a spark to jump between two metal electrodes.

1891
Baltimore inventor Clarence Kemp patented the first commercial solar
water heater.

1904
Wilhelm Hallwachs, discovered that a combination of copper and cuprous oxide was photosensitive. Einstein published his paper on the photoelectric effect

1914.
the existence of a barrier layer in PV devices was reported.

1916
Robert Millikan provided experimental proof of the photoelectric effect.

1918
Polish scientist Jan Czochralski developed a way to grow single-crystal
silicon.

1921
Albert Einstein wins the Nobel Prize for his theories (1904 research and techni-
cal paper) explaining the photoelectric effect.

1932
Audobert and Stora discover the photovoltaic effect in cadmium sulfide (CdS).

1947
Passive solar buildings in the United States were in such demand, as a
result of scarce energy during the prolonged W.W.II

1951
A grown p-n junction enabled the production of a single-crystal cell of germanium.

1953
Dr. Dan Trivich, Wayne State University, makes the first theoretical
calculations of the efficiencies of various materials of different band gap
widths based on the spectrum of the sun

1954
The PV effect in Cd was reported; primary work was performed by Rappaport, Loferski and Jenny at RCA. Bell Labs researchers Pearson, Chapin, and Fuller reported their discovery of 4.5% efficient silicon solar cells; this was raised to 6% only a few months later (by a work team including Mort Prince).

1955
Western Electric began to sell commercial licenses for silicon photovoltaic (PV)
technologies.

Mid-1950s
Architect Frank Bridgers designed the world’s first commercial office building
using solar water heating and passive design.

1957
Hoffman Electronics achieved 8% efficient cells. "Solar Energy Converting Apparatus," patent #2,780,765, was issued to Chapin, Fuller, and Pearson, AT&T.

1956
William Cherry, U.S. Signal Corps Laboratories, approaches RCA Labs’ Paul
Rappaport and Joseph Loferski about developing photovoltaic cells for
proposed orbiting Earth satellites.

1958
Hoffman Electronics achieved 9% efficient PV cells. Vanguard I, the first PV-powered satellite, was launched in cooperation with the U.S. Signal Corp. The satellite power system operated for 8 years.

1959
Hoffman Electronics achieved 10% efficient, commercially available PV cells and demonstrated the use of a grid contact to significantly reduce series resistance. Explorer-6 was launched with a PV array of 9600 cells, each only 1 cm x 2 cm.

1960
Hoffman Electronics achieved 14% efficient PV cells

1961
The UN conference on Solar Energy in the Developing World was held. The precursor to the PV Specialists Conference, the Meeting of the Solar Working Group (SWG) of the Interservice Group for Flight Vehicle Power, was held in Philadelphia, Pennsylvania.

1963
Japan installed a 242-W PV array on a lighthouse, the world's largest array at that time.

1964:
The Nimbus spacecraft was launched with a 470-W PV array.

1960
Silicon Sensors, Inc., of Dodgeville, Wisconsin, is founded. It starts producing
selenium and silicon photovoltaic cell.

Solar radiation map of the world

2007-12-11T06:42:00.000-08:00

At this post you will learn about various map of Solar radiation in the worlds, so you will able to more understand the radiation map of solar in the worlds. The solar energy impinging the surface of the earth is depicted at this picture below
This map divides the world into five solar performance area based on yearly averages of daily hours of sunlight and temperature

Source : http://www.oksolar.com

the red area is most powerful for Solar radiation power generation,
everyday there is plenty of energy from the sun hitting the earth but today those energy still doesn't have priority at the worlds, picture below taken from Nate Lewis of the California Institute of Technology, shown that six solar radiation power plant can produce about 20 Tera watts of electrical power. That would totally solve humanity's energy problem.

after we know the total energy average per years, we should known where is the total yearly energy capture potential of the site that determines the economical viability of installing a power plant.

at picture below shown USA solar radiation map

this map have same with previous but more clearly and this map is for Solar thermal energy map, not solar radiation,

The Solar Energy Resource

2007-09-20T13:11:00.000-07:00

The sun is a vast nuclear power plant of the fusion variety which generates power in the form of radiant 23 kW. An extremely small fraction of this is intercepted by Earth, but even energy at a rate of 3.8 x 10 14 kW. On the average, about 60% of this this small fraction amounts to the huge quantity of 1.8 x 10 energy, incident at the outer edge of the atmosphere, reaches the surface. To compare these numbers with our energy needs, consider the present electrical-generating capacity in the United States, which 8 kW. This is equivalent to an average solar radiation falling on only 1000 is approximately of 7 ﾗ 10 square miles in a cloudless desert area. It must, however, be remembered that solar energy is distributed 2
Compared to other over the entire surface of Earth facing the sun, and it seldom exceeds 1.0 kW/m sources, such as fossil fuels or nuclear power plants, solar energy has a very low energy density. However, solar radiation can be concentrated to achieve very high energy densities. Indeed, temperatures as high as 3000 K have been achieved in solar furnaces
Knowledge of the quantity and quality of solar energy available at a specific location is of prime importance for the design of any solar energy system, picture below show highest radiation area in the world, It is the primary task of the solar energy system designer to determine the amount, quality and timing of the solar energy available at the site selected for installing a solar energy conversion system.

Solar Energy Colection - Thermal type

2007-09-20T12:39:00.000-07:00

Various way able to catch the energy of heat from sun, us we know the fact from solat that :
ONE HOUR OF DIRECT SUNLIGHT = 1 KWH
1 KWH = 3,400 BTU’s
1 gallon of fuel oil = 150,000 BTU’s

The solar thermal energy is collected by concentrators the radiation to make heat more powerfully then the thermal use as boiler to run the generator and make electricity. same configurations of the concentrators are shown follows:
1. Disc System
Concave mirrors and lenses have been used for ages to concentrate the sun’s rays on a single point and therefore multiply its strength this type of concentrating solar collector that uses U-shaped troughs to concentrate sunlight onto a receiver tube, containing a working fluid such as water, The heat-conducting fluid is heated up to 400 ºC and by means of a turbine and generator then produces electric current, look at picture below for more detail

Parabolic Dish
The parabolic dish tracks the sun to focus heat, which drives a sterling heat
engine-generator unit. This technology has applications in relatively small
capacity (tens of kW) due the size of available engines and wind loads onthe dish collectors. Because of their small size, it is more modular than other
solar thermal power systems, and can be assembled in a few hundred kW
to few MW capacities. This technology is particularly attractive for small
stand-alone remote applications.
picture below show 25 kW Dish Stirling system at sunset at Stirling Energy Systems, Inc. (SES)/Boeing

Central Receiver
Solar thermal electric power plant generates heat by using lenses and reflectors to concentrate the sun's energy. and then stored, so they can generate power when it is needed, day or night, rain or shine.
In the central receiver system, an array of field mirrors focus the sunlight on the central receiver mounted on a tower. To focus the sun on the central receiver at all times, each heliostat is mounted on the dual-axis sun tracker to seek position in the sky that is midway between the receiver and the sun. Compared to the parabolic trough, this technology produces higher concentration, and hence, higher temperature working medium, usually a salt.
heliostat is Solar power towers use thousands of individual sun-tracking mirrors

Solar Energy

2007-03-21T07:42:00.000-07:00

Energy from the sun travels to the earth in the form of electromagnetic radiation similar to radio waves, but in a different frequency range, The sun's heat and light provide an abundant source of energy that can be harnessed in many ways. There are a variety of technologies that have been developed to take advantage of solar energy. These include concentrating solar power systems, passive solar heating and daylighting, photovoltaic systems, solar hot water, and solar process heat and space heating and cooling.

Solar power can be used in both large-scale applications and in smaller systems for the home. Businesses and industry can diversify their energy sources, improve efficiency, and save money by choosing solar technologies for heating and cooling, industrial processes, electricity, and water heating. Homeowners can also use solar technologies for heating and cooling and water heating, and may even be able to produce enough electricity to operate "off-grid" or to sell the extra electricity to the utilities, depending on local programs. The use of passive solar heating and daylighting design strategies can help both homes and commercial buildings operate more efficiently and make them more pleasant and comfortable places in which to live and work.
is constantly replenished and will not produce harmful pollution unlike fossil fuels. Solar energy may be used passively, such as to heat and light buildings, or technology may be used to harness the sun's energy by collecting it and transforming it to generate electricity. Current technologies include photovoltaics, concentrating solar, solar hot water