What Are Solar Panels?
Solar panels are technological devices able to exploit solar energy for electricity production or heating domestic water.
Taking the definition, we can say that a solar panel is „a panel designed to absorb the sun’s rays as a source of energy for generating electricity or heating.”
Mainly there two different types of devices used for different needs:
– photovoltaic panels;
– thermal solar panels;
Photovoltaic panels have the function of producing clean energy, while the second one makes possible the production of domestic hot water.
A photovoltaic system is a system composed of one or more solar panels combined with an inverter and other electrical and mechanical hardware that use energy from the Sun to generate electricity, while a solar thermal panels are devices that are mounted on your roof to absorb the sun’s heat and use it to heat water, stored in a cylinder.
How Do They Work?
The use of these panels is constantly growing.
Now we’ll find out how do they work.
While the photovoltaic solar panel uses the energy of the Sun to produce electricity, and consequently, it lowers the electricity bill, the solar thermal panel, on the other hand, uses the sun’s energy to produce thermal energy, which is used to heat water at variable temperature.
Their performance depends on several factors:
– quality of the components;
– absence of shading;
– the inclination of the panels (the optimal inclination is about 30 °);
– the orientation of the panels (the optimal orientation is towards the South);
– type of modules* chosen; *(we’ll find out the meaning in a while)
What Kind Of Installation To Choose
The kind of installation to choose depends on different factors:
First of all the energy consumption, which depends on the size of your house and the number of people living there.
The yearly energy consumption of a small house with two people is around 3200 kWh, and to cover this need, the solar panels must be able to cover the power of 3800 kWh.
To achieve this, you will need 15 solar panels of 260 Wp.
What we have seen until now is what are solar panels, how do they work, and we’ve made a distinction between photovoltaic panels” and thermal solar panels.”
Now let’s see more specifically the first one: photovoltaic panels.
-The photovoltaic system and system solar thermal panels
The photovoltaic system is composed of modules that convert solar energy into direct current, and is converted into alternating current through an inverter.
The types of photovoltaic systems;
Photovoltaic systems can be:
connected to the electricity grid (grid-connected).
Stand-alone systems are not connected to the electricity grid, providing a solution in those cases where the connection is not possible, such as in mountain shelters.
Grid-connected systems aren’t able to cover the energy needs of a household but can make a significant contribution to lightening the bills.
In cases where the energy generated by the plant exceeds the requirement, it can be fed into the grid.
System Solar Thermal Panels
As we said before, there is a different operation regarding thermal solar panels.
There is often confusion between photovoltaic systems and solar collectors, also known as thermal solar panels.
Despite both exploiting the sun, Solar COl is used for the production of hot water and space heating.
Solar thermal panels are mainly of two types:
– glazed floors;
– with the vacuum tube.
The first has the advantage of being less expensive and is particularly common in Italy.
The second, on the other hand, offers greater performance and is, therefore, a bit more expensive.
Always talking about the solar thermal panels, there is the most used system whose name is: the flat collector.
The flat collector is the most used system to obtain low temperatures, between 50 ° C and 90 ° C, which is easily obtained by heating the flat sun surfaces.
A flat collector consists of:
-A transparent glass plate, which allows incoming radiation to pass and blocks outgoing radiation
-A copper absorber, which is a good conductor of heat, contains many channels in which water or air circulates.
The Sun warms the plate, which in turn heats the water or the air.
-Thermal insulation, which prevents heat dispersion.
We can even mention other systems, such as:
– flat non-glazed thermal solar panels;
– glazed solar thermal panels;
– vacuum thermal solar panels; and
– flat air thermal solar panels.
The modules play a fundamental role in the functioning of the devices.
There are three different types:
– polycrystalline; and
– with amorphous silicon.
Solar panels with monocrystalline silicon are the most expensive and those with the highest performance and leare recognized for their black color.
Polycrystalline ones have a simpler and faster production process.
For this reason, their price, as well as their yield, is lower compared to monocrystalline panels.
However, the differences between the two variants aren’t so excessive – especially in the case of domestic installations.
Polycrystalline panels can have different colors and are generally blue or purple.
Between the two different kinds of a solar panel, there is a difference in colors: monocrystalline panels are black, and polycrystalline panels are generally blue or purple.
Finally, panels with amorphous silicon are the type with the lowest performance and the lowest cost.
These do not use silicon crystals like the two previous types, but silicon powder, which makes them more flexible.
Because of their lower efficiency, they occupy a greater surface area than poly and monocrystalline panels.
They can be effective in case of high temperatures.
Got to this point, we could ask ourselves why to install solar panels on our home.
In addition to economic reasons, many choose to install a photovoltaic system also for ecological reasons: the use of renewable energy sources makes it possible to reduce its ecological footprint, reducing carbon dioxide emissions into the atmosphere.
Talking about the benefits aspect, we can say that becoming part of the world of renewables involves a lot of advantages that touch our family as much as the environment in which we live.
Photovoltaics produce clean energy without CO2 emissions and reduce our dependence on the price of alternative raw materials on the market.
They also lead to a significant reduction in the bills and allow us to save money which we can then use for other purposes.
Furthermore, the value of a house equipped with a photovoltaic system increases, and this represents a strength because of a possible future sale.
Now let’s talk about another important aspect that also concerns this field:
Most components of a solar module can be re-used.
Thanks to the technological innovations that have occurred in recent years, up to 95% of some semiconductor or glass materials, as well as vast quantities of ferrous and non-ferrous metals used in photovoltaic modules can be recovered, a remarkable and very important fact.
From a standard 21 kg module, about 15 kg of glass, 2.8 kg of plastic, 2 kg of aluminum, 1 kg of silicon powder, and 0.14 kg of copper can be recovered, of course, very good news.
Taking as an example, Italy, more than 100 million photovoltaic modules are installed, and the module recycling market will start in a few years, considering that the lifetime of a photovoltaic system is 20-25 years.
With the new technologies recently introduced, however, it’s already advantageous to replace the old modules with those of the latest generation that guarantee greater efficiencies.
Let’s see how photovoltaic modules are recycled.
It takes place in three steps: in the first one, the aluminum frame and the electrical branches are mechanically separated. In the second one, the EVA, the glass, and the Tedlar are separated from the cells, this can be done either by a thermal process or by a chemical process.
In the last step, the silicon must be purified from the antireflection layer, from the metals and the semiconductors, and so a chemical treatment or purification by laser is used, which, however, has high-cost low efficiencies and long times.
Till now, we’ve seen what the solar panels are, how they work, and in how many and which types they’re divided.
Of course, as already mentioned, one of the fundamental factors is solar energy (Solar energy is the energy associated with solar radiation and is the primary source of energy on Earth), without which the process of transformation into energy wouldn’t be possible.
Heat Home With Solar
To have a house heated by solar energy, it must first of all be equipped with good thermal insulation.
This one has to be capable of reducing consumption for space heating.
Among the various types of thermal plants we have: the Combi (combined) plant that produces both ACS and energy to heat the house.
With this type of system, it’s also possible to supply a cooling system for the summer period or to heat a swimming pool.
The size of the system depends on energy consumption and other technical features of the house.
If we reduce the energy needs of a building, we make it more suitable to be heated with a solar heating system.
By reducing the demand for thermal energy, the relative contribution given by the solar system increases and also reduces the effects of a possible summer overproduction.
A properly sized system can meet the energy needs of your family and allows you to lower your electricity bill, ensuring savings of up to 40% thanks to direct self-consumption.
The energy produced by the photovoltaic system, in fact, is fed directly into the home network and is ready to be used for lighting, TV, dishwasher, and all small and large appliances.
By integrating a heat pump into the photovoltaic system, you can completely reduce the cost of the gas bill, as regards the production of domestic hot water and heating.
The latest generation appliances work both as water heaters and air conditioners: by exploiting the natural heat present in the air, they produce thermal energy and transfer it to the water system.
They do not require gas, oil, or any other type of fossil fuel, but they use the electricity produced by the photovoltaic panels for kindling, continuing to function thanks to the heat available in nature.
Counting that 75% of a family’s consumption comes from heating, the heat pump is certainly a convenient and very advantageous solution for those who have already decided to exploit a renewable source such as the sun to satisfy their energy needs.
A photovoltaic system has a cost, not only initial.
As many are subject to think, there are numerous costs that are part of the life span of the entire plant and are related to its functionality, its maintenance, its cleaning and, its insurance.
An important starting point before buying and choosing a photovoltaic system for your home is to know all the primary factors that vary, increase, and reduce the initial price of a photovoltaic system.
Making a general estimate, it’s possible to say that a photovoltaic system for a standard house of around 100 square meters has a cost that is around € 3,000 per kW installed.
In the initial purchase of a photovoltaic system, there are additional costs to be considered, which are:
-the price of the photovoltaic panel;
-the installation phase and the necessary components for its durability and resistance on the roof as the supporting structures of the photovoltaic panel;
-phase of planning and installation of the photovoltaic system on the roof; and the
-installation phase and need for masonry work on the roof to install the photovoltaic system.
Currently, most of the studies focus on new generations of photovoltaic cells with greater efficiency.
More ambitious studies point to the creation of orbiting solar power plants.
These plants should collect solar rays directly into space and transmit the power absorbed to the Earth using and microwaves or laser beams.
The energy obtained through the use of solar panels can bring many benefits, and over time, it becomes more and more normal to see solar panel installations on different houses and structures of all kinds.
Surfing the Internet, we can see that many say they’re satisfied with their choice to change, so why not get better informed and make the right choice?