The solar energy can be used in two different ways. As once did Romans Greeks and all the classic peoples who worshiped you can use the heat energy that gives us, so, with solar collectors of different types, heaters and concentrators can heat water, but not at very high temperatures, they can not overcome the 4000 ° k so that solar energy will not be useful when melting metals in blast furnaces etc. .
But some things can be achieved, depending on the ingenuity of the designer and the technological possibilities: To collect the heat energy from the sun several devices are used for flat plate collectors: flat plate collectors intercept solar radiation on an absorber plate by passing the so-called carrier fluid.
(This, in liquid or gaseous state, is heated passing through the channels by heat transfer from the absorber plate).
The energy transferred by the carrier fluid, divided by the solar energy incident on the collector and expressed as a percentage, is called instantaneous collector efficiency. The flat plate collectors generally have one or more transparent plates to help minimize heat loss from the absorber plate in an effort to maximize efficiency coverts. They are capable of heating carrier fluids up to 82 ° C and get between 40 and 80% efficiency.
The flat plate collectors have been used effectively to heat water and for heating. Typical systems used for home-room fixed collectors mounted on the roof. In the northern hemisphere they are oriented towards the south and south to the northern hemisphere.
The optimum angle of inclination to mount the collectors depends on the latitude. In general, for systems used throughout the year, such as producing hot water, collectors are tilted (the horizontal plane) equal to 15 ° latitude angle latitude and 20º S and 20º latitude orient N, using so more solar energy.
In addition to the flat plate collectors, typical hot water systems and heating consist of circulation pumps, temperature sensors, automatic controllers to activate the pump and a storage device.
The fluid may be both air and liquid (water or water mixed with antifreeze), while bedrock or an insulated tank serve as storage of energy.
Concentrating solar collector energy:
For applications such as air conditioning and central generation of energy and heat to cover large industrial needs, flat plate collectors do not provide fluids with temperatures high enough to be effective. They can be used in a first stage, and then the fluid is treated with conventional heating means. Alternatively, collectors can use more complex and costly concentration.
They are devices that reflect and concentrate solar energy incident on a small receiving area. As a result of this concentration, the intensity of the solar energy increases and temperatures receptor (called “target”) can approach several hundred or even thousands of degrees Celsius.
Concentrators must move to follow the sun if they are to act effectively; the devices used for this are called heliostats, mirrors that are mechanically moving or computerized control to reflect the maximum amount of solar radiation at the target.
Ovens solar energy are an important application of high temperature concentrators. The biggest, located in Odeillo, on the French side of the Pyrenees, has 9,600 reflectors with a total area of about 1,900 m2 to produce temperatures up to 4,000 ° C.
These furnaces are ideal for research that requires high temperatures in pollutant-free environments, for example in materials-research.
Central receivers of solar energy:
Centralized electricity generation from solar energy is developing. The concept of central receiver power tower or a matrix of reflectors mounted on computer-controlled heliostats reflect and concentrate the sun’s rays on a water boiler situated on the tower. The steam generated may be used in conventional cycle power plants to generate electricity.
The houses of the future:
Often speaks of smart homes, houses built and specially designed to reduce household energy consumption by focusing especially on energy saving and heat loss. These smart homes, for example have large windows facing south to heat inside in winter and some blinds designed to generate inside a refrigerated space in summer, without spending all electric or fossil energy for heating or cooling.
Also the walls are constructed from ceramic materials that keep heat in winter and in summer expel addition to using concrete tanks or water tanks to keep the heat for the winter night.
These small changes in our lifestyle as smart homes or use double glazing, insulate the house to avoid losses etc. to avoid the risk of passing as in photography; will make in the future global energy consumption is reduced considerably and so, like a domino effect, can save nature and our quality of life much better.
As described in the introduction, and in relation to the previous point, there is theoretically what are called black bodies (bodies would be able to absorb all the radiation incidiesen upon him), that if someday encontrasen would be a invaluable as devices such as flat plate collectors and solar cells would yield very close to 100% and the scientists only have to worry about how to avoid heat loss and electric resistance and the like; the energy crisis would be solved, with solar energy solution.