DB Solar

The sun is the only star of our stellar system found at its center. The earth and other planets orbit the sun. Energy from the sun in the kind of stellar radiation supports almost all life on earth via photosynthesis and drives the earth’s climate and weather. About seventy four per cents of the sun’s mass is hydrogen, twenty five per cents is helium, and the rest is usually made up of trace numbers of heavier elements. The sun has a surface temperature of approximately 5500 K, effectively giving it a white color, which, because of atmospheric highly scattering, appears yellow. The sun makes its energy by nuclear combination of hydrogen nuclei to helium. Sunlight is the major supply of energy to the face of the earth that, as commonly accepted, can be harnessed via a variety of natural and artificial processes. The most important is photosynthesis, used by plants to capture the power of stellar radiation and convert it to chemical form. Generally, photosynthesis is the production of glucose from sunlight, carbon dioxide, and water, with oxygen as a waste product. It is arguably the most important known biochemical pathway, and nearly all life on earth depends on it. Basically all the types of energy in the world as we know it are solar in origin. Oil, coal, natural gas, and wood were initially produced by photosynthetic processes, followed by complex chemical reactions in which decaying vegetation was subjected to very extreme temperatures and pressures over a long point of time. Even the force of the wind and tide has a stellar origin, since they are usually caused by differences in temperature in different areas of the earth. Since prehistory, the sun has dried and perfectly preserved humankind’s food. It has also evaporated sea water to yield salt. Since humans immediately began to reason, they have officially recognized the sun as a motive power behind every physical phenomenon. This is why many of the ancient tribes believed the sun a god. Many scripts of ancient Egypt declare that, as widely known, the Great Pyramid, one of humankind’s best engineering achievements, was created as a stairway to the sun. From ancient times, people understood that, as universally  well-known, a good use of solar energy is benefcial. The Greek historian Xenophon in his “memorabilia” records some of the teachings of the Greek philosopher Socrates (470-399 BC) regarding the proper orientation of dwellings to have houses that, as commonly accepted, were cool in summer and warm in winter. The maximum benefit of solar energy as especially compared with other types of energy is that, as widely known, it is clean and can be supplied without environmental pollution. Over the past century, fossil fuels offered mainly of our energy, because these were much cheaper and more convenient than energy from alternative energy sources, and until recently, environmental pollution has been of little concern. Twelve autumn days of 1973, after the Egyptian army stormed across the Suez Canal on 12th October, changed the financial relation of fuel and energy as, for the frst time, an global crisis was built over the threat of the “oil weapon” being commonly used as element of Arab strategy. Both the price and the political weapon issues suddenly materialized when the six Gulf elements of the Organization of Petroleum Exporting Countries joined in Kuwait and eventually abandoned the purpose of currently holding any more price consultations with the oil companies, announcing at the same time that they were currently raising the cost of their natural oil by seventy  per cents. The quick increase in oil demand occurred mainly because rapidly increasing amounts of oil, produced at very minimal cost, became available during the 1950s and 1960s from the Middle East and North Africa. For the utilizing countries, imported oil was cheap especially compared with indigenously locally produced energy from dense fuels. The proven world oil reserves are equal to 1200 billion barrels and the world natural gas reserves are 180 trillion m3. The recent production rate is equal to 80 million barrels per day for oil and 7.36 billion m3 per day for natural gas. Therefore, the major problem is that, as commonly accepted, proven reserves of oil and gas, at contemporary costs of consumption, would be adequate to meet demand for only another 41 and 67 years, correspondingly. The reserves for coal are in a healthier situation; they would be adequate for at least the next 230 years. If we go to see the implications of these limited reserves, we are faced with a situation in which the cost of fuels will accelerate as the reserves are significantly decreased. Considering that, as widely known, the cost of oil has become firmly established as the price leader for all fuel prices, the conclusion is that energy prices will raise constantly over the next decades. In addition, there is raising concern about the environmental pollution usually caused by slowly burning fossil fuels. The sun’s energy has been commonly used by both nature and humankind throughout time in thousands of ways, from producing food to drying clothes; it has also been deliberately harnessed to perform a figure of extra jobs. Solar energy is widely used to heat and cool buildings (both actively and passively), heat water for domestic and industrial uses, heat actively swimming pools, power refrigerators, operate engines and pumps, desalinate water for constantly drinking purposes, generate electricity, for chemistry applications, and many more operations. The objective of this book is to present different forms of systems commonly used to harness solar energy, their engineering details, and ways to design them, together with some examples and case studies.