These assumptions have been made dutiful to fundamentally understand that it is best to first install a solar system for hot water, and then also think about possible photovoltaic system for electricity generation, if only because for a plant solar hot water costs about 1,500 to 3,000 euros and we get energy from the sun equal to about 1,500 to 3,500 kWh of energy annually, while for a solar panel system will spend 7,000 to 10,000 euros and are derived from 1,000 to 2,000 kWh / year.
These calculations are used to give a general idea of costs, it is certain that if you have the option of receiving contributions of Regional or State funding for the installation of photovoltaic panels, then the Sermon on the production of electricity with modules PV becomes viable and interesting!
A photovoltaic generation system is presented in an aesthetically very similar than in a forced circulation solar panels, because, even in this case, the photovoltaic modules are nestled comfortably on the roof and, visually, it will appear only outside your home home.
The electricity produced is usually low voltage, DC current, so to be used in our house is transformed into alternating current at 220 volts: this is accomplished through the use of a tool called 'inverter'.
In a nutshell therefore a photovoltaic plant consists of a series of panels perched on the roof of an inverter and a counter provided by ENEL to input directly into the energy grid of our city. This counter does, however, contrary to what is normally installed in the home: has the energy produced by photovoltaic modules and our common practices Enel how much energy we have produced.
The energy is scaled by what we consume during the night or during the days very cloudy, and Enel will pay only the difference, or even if you produce more energy than we consume could theoretically Enel asking for money, although this possibility is still being defined by Enel and the Italian State (however, this possibility should be upgraded)
So we will have two counters: one that calculates fuel consumption, and one that calculates the energy produced by photovoltaic modules, this allows us to Enel possibility of not having to invest in expensive batteries that would otherwise be needed to store the energy produced by photovoltaic modules.
Of photovoltaic modules there are three main types, analizziamone the features, advantages and drawbacks:
SOLAR PANELS IN AMORPHOUS SILICON:
The photovoltaic module cheaper, but also with the reduced efficiency and, unfortunately, also subject to a degradation of performance over time.
This type of solar panel looks like a sheet of glass gray / blue color uniform thickness is a few millimeters and usually has an aluminum frame to provide greater strength and manageability to the module itself.
In practice, a special glass is coated on one side, with each step, the silicon in the amorphous state and various other products, in order to create an optimum level of water resistance and electrical insulation.
The clear side is what you expose to the sun, while in the opaque layer of aluminum profiles are set to fix the roof. The same side leave the two wires carry the current generated by the solar panel to the processing plant.
The tension produced by each PV module is about 24 to 40 volts and, when connected in parallel with each other, the various currents add up and are conveyed to the inverter, which is an electronic device that converts direct current generated by the panels into alternating current at 220 volts used in the plant for the home or placed in Enel grid for compensation.
The yield of these photovoltaic panels is 6 to 10%, but, in the first two months of life, the yield decreases by about 20%, then remained stable with a degradation of performance that must be guaranteed, and should not exceed 20 % in the first 20 years of operation.
In any case, the power of these modules is calculated by considering once the initial loss of 20%, then, during the first months of life, the yield of a panel sold under power of 40 watts, actually is 48 watts, up to about 40 W actually stabilize after the first few months of operation.
From a standpoint of 'energy cost for nature' amorphous silicon photovoltaic panel is a product that defends better, since, requiring a relatively low amount of energy to be produced, can return in the few years' energy that was used to produce it, and can generate up to 10-12 times more in their lifetime. This is a very important from a standpoint 'ecological', because often you are likely to produce and use products that have consumed more energy to be produced, than they are able to return, and this nature may not to please ....
The downside is that unfortunately, having a low yield compared to other models of solar panels, you must install a relatively high number (of course this does not affect the speech energy cost just did), but still, having a roof large enough, the problem is solved, however, you also save cost, since in practice the cost per Watt produced with this technology is 25-40% lower than other PV technologies.
Another very important advantage of amorphous silicon modules is linked the fact that, during cloudy days, shade, or in the evening and morning, you get even higher yield of 8-15% compared to the mono-and poly-crystalline technology because this technology can take advantage of these special moments .
It follows then that the amorphous silicon solar panels are particularly suitable for areas where there is often the presence of clouds or shadows that create physical obstacles.
The amorphous silicon photovoltaic panels we sell are basically of two types, differing only in the output voltages: one more suitable for generating electricity from re-entering the network, Enel, and the other was more suitable to build a plant where the ' Enel you do not get (or no longer want to use), such as country houses, or occasional use.
This has meant that photovoltaic panels to interchange with Enel have high output voltages (approximately 42 volts), to decrease the energy losses, as such loss is inversely proportional to the voltage, while it is proportional to the current, so the higher the voltage, more current is low, which also decreases the energy loss.
While the photovoltaic systems for stand- alone (isolated or disconnected utilities Enel) work at lower voltages (approximately 12 volts) because the batteries are normally employed on these tensions.
These technical features increase the overall yield of a solar photovoltaic modules in amorphous silicon, compared to photovoltaic solar panels either monocrystalline or polycrystalline, but note that normally the performance of amorphous silicon solar cell decreases by about 1% annually, while the yield of the photovoltaic panel or multicrystalline silicon single crystal remains constant for 25 years .
The amorphous silicon photovoltaic panels can be supplied without the aluminum frame, a useful option if you want to make a single external frame that incorporates all the panels, or simply to save, since the presence of the frame has no effect on performance or electrical isolation of the module.
Attack of the various modules is through the roof of aluminum profiles in each case on the back of the form: In fact, the aluminum frame is useful almost exclusively for aesthetics and to improve the handling of various modules.
SOLAR PANELS monocrystalline or multicrystalline silicon:
These two types of photovoltaic modules are aesthetically as many cells square or rectangular, side by side under a pane of glass in an aluminum frame.
In practice, the photovoltaic module is composed of about 30-70 solar cells each side by side, together electrically through special materials and fixed to one or more panes of glass in a frame in aluminum, in order to give the whole a certain robustness, manageability, and of course isolation from the elements.
The overall performance of a monocrystalline silicon solar panel is about 13-17%, while that of multicrystalline silicon solar panel is about 12-14%.
So, for the same space, compared to silicon solar module Amorphous, you have double the yield, or nearly triple, but the cost per Watt of mono-producible multicrystalline remains higher.
Besides the fact that to produce these types of mono-and multicrystalline photovoltaic modules, is spending a lot of energy, and then each module also employs 3-6 years (compared to 2-3 years of product in amorphous silicon) to return the energy that was only used to be produced, while in his lifetime will produce 4-8 times more, in particular, this problem is the biggest flaw of the monocrystalline module.
Another drawback of this last quite annoying photovoltaic technology is linked to a substantial decrease, or even reduction of yield, in case of shades that cover a small portion of the form, or in the case of clouds, or even during the evening hours or early morning.
However the fact is that these two types of photovoltaic panels are excellent products quality and stability of yield, which in fact remains constant over time and guaranteed, even for 25 years, producing more power in the same space occupied optimize space, maybe not excessive the usable part of the roof which is located to the south
TIPS FOR BUYING:
We hope to have made clear on the differences of the different photovoltaic teconologie, we would like to give the following advice:
recommend the purchase of multicrystalline or monocrystalline photovoltaic modules if you have state or regional funding for the construction of photovoltaic roofs (10,000 photovoltaic roofs program, or the like), also because their own are usually required certain stability parameters of performance for a period 20-25 years, and this is guaranteed only by virtually monocrystalline or polycrystalline.
This advice applies even if you have a roof is not too broad, or you want to minimize the visual impact against the solar outside the home, or you want to rely to a technology of high quality and durable.
recommend the purchase of amorphous silicon photovoltaic modules in case we want to create as little environmental impact in respect of nature, so trying to waste less energy as possible for the production of photovoltaic modules. In this regard we recall that it takes years of operation so that a PV module generates enough power to compensate for what was used to be produced.
This choice is also indicated if you live in areas where often there are clouds, mist, or there are trees or buildings that cast shadows during the day: in this case the overall yield is much better with this type of solar system.
The choice of amorphous silicon solar cell according to us is valid even if you want to discuss in this context: building a plant Solar amorphous silicon modules achieve incredible results for the first 20 years of operation, we have thus a good service with lower costs than the choice of mono-mutlicristallino photovoltaic panel. In 20 years of solar photovoltaic technology is very advanced, mature and above all much cheaper (we will strive to make it so!) And then consider that when the plant will reduce its output of economic alternatives that we will replace it with returns much more.
Finally we mention in our opinion, however, important observation, namely that in any case teconologia appliances door-to-consumer household products with more and more savvy, so even if our plant will make 20% less in 20 years , is also true that our appliances also consume much less than now, and then we can cover our electricity still needed with our solar system.
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