The solar energy
he solar energy was already used in ancient Greece mainly in architecture. The ancient Greeks used solar energy to heat their houses, because they had cut out all the trees in the Greek areas, and the import of the trees was very expensive.
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The past, the presence, and the future
of the solar energy
The meaning of the solar energy: Natural, regenerating source of energy. It is coming from our sun. This kind of radiating energy gets free, when hydrogen atoms unite to helium. While one kg of helium is developed 180 KWh-s of energy gets free. From the sun to the atmosphere gets approximately 1,37KW/ square meters energy while to the ground it arrives only 0,34KW/square meters. To the ground it gets 12000 times as much energy as the worlds whole energy consumption is.
The solar energy was already used in ancient Greece mainly in architecture. The ancient Greeks used solar energy to heat their houses, because they had cut out all the trees in the Greek areas, and the import of the trees was very expensive. So they had to find out a new source of energy. They started solar architecture, which means that they built their houses, so that the houses could intercept the sunshine. The buildings were open on the south side. This way the sun could easily warm up the rooms in the building. The north side of the house was well built , it had large walls so the house was well protected against the north wind and cold. The ancient Greeks used solar energy this way.
In the Roman Empire the solar energy was used for the same purpose and a similar way, but they developed on the Greeks technique. So they built different houses for areas with a different climate. Besides they used glass for windows. So their houses were more protected against wind and cold. The glass also made the glass house effect, because sunshine got through the glass easily but the wind and cold couldn’t.
Usage of the solar energy in the middle age and in the Renaissance
In these times the solar architecture was forgotten and people tried to use solar energy for tactical purposes. So they wanted to set enemies, ships , and houses on fire with the help of concave mirrors. Some famous natural-scientists also were interested in these plans. For example Leonardo Da Vinci ,and Roger Bacon. In the 1200s Bacon suggested the catholic church should set the Arabic army with concave mirrors on fire which attacks the crusade. From year 1600 bigger and bigger parabolic and ground mirrors were built. These mirrors were 2-3metres in diameter. These had disadvantages too. For example if they were made from one piece they were very heavy. For these problems Peter Hoesen who found the solution in the 1700s built his mirror from segments. He also put wheels on his mirror ,so it could be transported easily. To boot the angle could be changed too.
The spread of the glass houses: From the XVI. century spread fast in Europe. These were founded on the glass house effect. The sunshine gets easily trough the windows than it warms up the inner place, because the windows don’t let the sunshine out. The glass houses spread because of the big discoveries, because the plants brought from the new explored areas needed warm and suitable circumstances to be grown. There was often glass house built near flats, which had a window so the glass house could warm up the flat. However after the First World War the popularity of the glass houses started to get lower.
Significance of hot boxes: People knew glass house effect from the ancient times, but its scientical examination started in the end of the XVIII. century. In 1767 Horace De Saussure a French natural philosopher was who made first experiments about the glass house effect. For his experiments he made a well insulated and big wooden box, on which he could fix several layers of glasses. He called his apparatus hot box because at first in the box the temperature was 190,40 Fahrenheit. After some perfection the temperature in the box reached the 228,20 Fahrenheit.
Sir John Herschel the famous astronomer built a similar hot box too, which he used on his expeditions to cook. Not much later Samuel Langleg proved that 212,00 Fahrenheit also can be achieved where the temperature is under freezing point. The significance of hot box examinations is that they served as a basis of the warm water producing sun collectors.
Warming water with solar energy: The usage of solar energy to warm up water set off from the United States. In the beginning people put black barrels on their houses. In sunny weather these barrels warmed up in one or two hours and there was warm water. However the black barrels had the disadvantage that if the weather wasn’t sunny the barrels cooled down very fast. This problem was solved by Clarence Kamp in Baltimore, in 1891. He put the barrels in glass covered glasses, so because of the glass house effect the heat insulation became better. So that he made the Climax water heater mechanism, which claimed a huge success. After that several people improved Kamps idea. So did Charles Haskell ,who perfected the mechanism. Instead of the cylindrical barrels , which got warm slowly used flat cisterns with a big surface. This way the water could warm up faster. In 1909 William Bailey developed the machine. The new machine was able to produce warm water at night too with a big output. He adapted a store cistern to his mechanism. The store cistern was upper than the water heating collector so the warm water went into the store cistern because of the conventional measures. The cold water was supplied with an automatic valve. This technique was used since the end of the 1920s in California.
In the 1925s making sun collectors was very popular in California. They made further perfections. For example they conducted the water through the collector in thin pipes. In addition they used a pump which circulated the water. In Israel people used sun collectors too because Israel was pour in oil and natural gases, but it is in the sunniest region. In the 1940s Levi Yissar founded the first sun collector works in Israel. Producing of these collectors was for decades as popular as in California, however after the six days war in 1967 in which Israel conquered the Sinaian peninsula with its big oil, and natural gas stocks the produce of the collectors got lower and lower. After the war the cheap oil and gas for a short time crowded out the collectors from the economy. In these times people used the primer circuited and the most simple collectors because they were cheap with a simple buildup and a good efficacy.
Solar energy in architecture, or the houses of Massachusetts Institute of Technology:
The investment started in the USA in 1938 and terminated in 1962. The reason of starting this engagement was to find a solution for heating the houses with solar energy. Those days heating the houses took much more energy than the whole industry of the USA took. The program was supported by a businessman from Boston. He gave 650000$ (USD). During this program four houses were built, in which the builders would like to make the hot water support and the hot-water heating with the usage of solar energy.
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