The Incredible Solar Energy

Summary
If we could harness a miniscule of solar energy then the entire need of electrical energy created from other renewable and non-renewable resources could be solved. All the 44 renewable energy resources so far identified, have the Sun as primary source. In future nano technology may offer a solution to miniaturization of large volume and mass of equipments needed for converting solar energy into electrical and thermal energy. The rendezvous to the Mount Everest may become a matter of adventure fun. Our Sun is a star. With billions of stars as powerful as our Sun in the universe acting as power stations, are we not nearing the expertise used in UFO’s which facilitates their journey of millions of light years a matter of sightseeing?.

The Incredible Solar Energy
The Earth receives sunlight all the 24 hours of the day. When the Sun is above the horizon, it is day light. When the Sun is hindered by clouds or reflected off by other objects, it comes in as diffused light. Technically, when an Earth’s surface receives 120 watts per square meter of solar radiation then that period of time is termed as sunshine duration. Bright sunlight falling on the surface of Earth has a luminance of 100,000 lux.
The universe that we have fathomed has around 3 to 7X 1022 (30 to 70 sextillion) stars spread over 80 billion galaxies. Sun is a star of the Milky Way galaxy. Sun is brighter than about 85% of the stars in the Milky Way, most of which are red dwarf. The surface temperature of the sun is 5778 degree Kelvin.
The Sun emits radiation in the form of electromagnetic waves. The entire spectrum from 100 to 100,000,000 nanometer starts from Gamma rays, X rays, ultraviolet, visible, infrared, microwave and radio waves with cosmic radiation participating during galactic alignment by Proton-Proton cycle. The visible part of solar ray is only about 0.004%of the total spectrum spanning only 400 nm between 380 to 780 nm.
Of all the known energy resources, solar energy is the largest. The word ‘infinite’ can be easily used for it. The land masses, ocean and the clouds absorb about 70% of the incoming solar radiation. This incoming solar energy in one year is twice as much as could be obtainable from all known actual and potential resources of non-renewable energy. This is approximately 3,850,000 exajoules per year. The world uses energy equivalent to one hour of this energy in a year. This solar energy reaching the Earth atmosphere is only a miniscule of the total energy radiated from the Sun. Around 174 petawatt of solar energy reaches Earth’s surface of which 30% is reflected back.
All the other 44 identified renewable energies have Sun as its primary source. Geothermal energy has also ancestral link with the Sun. Tidal energy is linked to the Sun via the moon.
Solar technology got a start in the 1860’s.Commercial solar water heater became viable in the United States by the 1890’s. Increasing availability of coal and petroleum suppressed its development in the early 19th.century. It again got impetus from the oil crisis of 1973 and energy crisis in 1979. There has been a steady increase of 20% since 1999.
Man has been using solar energy since the beginning of his existence. He based his agricultural pursuits on solar energy and rain. He built his home which could easily be termed as a green home. Before, he knew fire; he must have been preparing delicacies using solar heat. As if we have taken a clue from our ancestors, we are using solar technologies in almost every field, namely architecture and urban planning, agriculture and horticulture, lighting, heating and cooling, ventilation, cooking, water treatment etc. In ancient times, passive solar technologies were practiced. Now, both active and passive solar technologies are in use. Passive technologies are generally immovable such as selecting materials with desired thermal mass or light dispersion, orienting a building to the Sun to get desired seasonal results, designing spaces having naturally circulating air and the likes. Active technology is conceived into manufacturing and using photovoltaic panels, solar heat collectors etc. to capture solar energy.
Solar energy got wide attention as it was identified as a viable alternative to fuel based electrical energy with the natural resources dwindling at a faster rate.
Solar lighting can reduce up to 25% of lighting related energy. This is achieved by designing building to capture solar light where it is needed and avoiding where it is not needed. This is accomplished by careful selection of window with respect to its size, orientation, single or double paneling, and its location. Saw-toothed roofs, light shelves, skylights such as north windows, light reflecting tubes strategically placed keeping glare in perspective, total heat flux and movement of the Sun, are some of the most used technologies to derive sufficient Sunlight. Active solar energy may be incorporated with hybrid solar lighting using focusing mirrors set with the proper angle of reflection together with optical fibers that transmit Sunlight into building. Solar light using phovoltaic panels and batteries are used for street and pathway lighting.
Urban Planning & Architecture for humid and hot subtropical climate is based on orientation of buildings relative to the movement of the Sun. Surface area exposed to the Sun is kept low in comparison to the volume of the building thus minimizing absorption of large radiation. Shading or overhangs are so located that the same give greater protection from the solar heat. The building is made with materials having low thermal mass which remains insulated. Similarly good ventilation is achieved by taking benefit of the wind rose diagram of the year round. Green belt is developed with dense trees and bushes to provide fresh air and shade. The leaves of the trees further adsorb dust and particulate matters thus cleansing the environment. By painting the roof, walls and the roads with white paint has been found to decrease the ambient temperature by at least 3 degree Celsius. Further computer programmed enrichment for solar heating, lighting and ventilation together with active solar equipments such as fans, pumps and switchable windows help in lot of saving.
The world has over 200 GW of total installed capacity of solar water heating system with Chile leading the deployment with over 75 GW. Over 90% of residential complexes and homes are using this system in Cyprus and Israel. Solar water heaters for domestic application comes in two varieties; evacuated tube collector and glazed flat plate collectors. Such facility for swimming pool water heating comes as unglazed plastic collectors. USA, Australia and Canada are the largest user of unglazed system. Solar thermal technologies are also being used for process water heating, space heating and cooling.
Requirement of solar energy for various crops and plants is different. Modern agricultural and horticultural technologies make use of customized solar radiation by way of timed planting cycles, staggered height between rows and changing row orientation. Mixing of plant varieties such as placing plants needing less solar radiation by the side of high agricultural growth gives a higher yield. Solar energy is further utilized in drying crops, pumping water, brooding chicks, drying manure and fuel woods. Glass houses and now covers of tarpaulin and PVC tents to develop greenhouse effect for rearing plants and fruits all through the year have brought about a revolution in higher yield and availability of winter fruits in all seasons.
Solar energy is being used for water distillation, waste water treatment, water disinfection, and water desalination. Solar distillation by double slope stills is most economical and is in greater use for domestic purpose. Large scale application of solar energy for distillation makes use of multiple effect units. These stills can operate in active, passive or hybrid mode. Water filled polyethylene terephthalate bottles are exposed to harsher Sun light for at least 6 hours to several hours to achieve disinfection. Water stabilization ponds to treat waste water have been a natural process of anaerobic treatment using solar radiation. Growth of algae in such water ponds further consumes Carbon dioxide. Such water can be safely used for gardening or industrial processes.
Solar cooker has become a household feature now. Solar bowl, its developed version, in which a spherical reflector concentrates the falling radiation, is capable of raising the temperature of water to 150 degree Celsius. Flexible parabolic dishes in tandem combine solar energy whereas polar trackers rotate to keep it facing the moving Sun. Such arrangement can attain 650 degree temperature. Tracking cookers are employed in Rajasthan and Shirdi (India) for cooking 40,000 meals in a day. Solar concentrating technologies are being widely used for providing process heat for commercial and industrial applications. These are extension of ancient ideas of concentrating salt from evaporating ponds or drying clothes spread in air and Sun.
Solar power plants utilize solar energy by conversion into electricity using photovoltaic cells. Now the process has been modified to use concentrated solar power through lens, mirror and tracking to obtain a large concentration of Sunlight for most of the time and large array of PVs to get enough electrical energy. The largest solar power plant is the 354 MW SEGS unit in the Mojave Desert in California.
Solar powered vehicle, solar sail, solar balloon, high attitude airship, are some other area where solar energy may be competing with other conventional and non-conventional energy resources.
Since solar energy is Sun dependent, its availability in the night hours has become the key to its profitable use. Various energy storage media are being deployed which have high thermal mass such as salt, water, Earth and paraffin wax. Glauber’s salt and molten salt have been found to give encouraging result with proven capacity to keep temperature around 64 degrees Celsius. Traditionally, Photo voltaic systems use rechargeable batteries to store excess electricity. With grid ties systems such excess electrical energy can be linked to transmission grids.
With the onset of nano technology there is every possibility that solar energy would be utilized at far off, remote and difficult places such as the Mount Everest. All the equipment, kits, gears and dresses including tents needed at such places may be harnessed with miniature photovoltaic cells produced from nano technology with tremendous capacity to convert solar energy into electrical energy.
Our Sun is a star. All stars are as powerful as the Sun. There are billions of stars in the universe that we could fathom so far. There may rest the secret of unidentified flying objects getting recharged to float to millions of light years without having inconvenience of carrying loads of liquid fuel as we do.