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Category ArchiveRenewable energies and Systems


DECALOGUE of energy saving







  1. Use public transportation to go to school or prefer a bike to a car (anything but a diet!)                           
  2. Instead of taking the elevator, go up the stairs on foot. This will also do your figure good.
  3. If you are hot, do not open the window, ask for lowering the heating (or get undressed ?!)
  4. If you are cold, put on your wool sweater (they say it is sexy…)                                                                       
  5. When you leave the classroom or the building, close the door (do have you got a guilty conscience?)                                                                                                                                                     
  6. Do not keep the light bulbs on when they are not necessary. Turn off the bathroom light (after hitting the target!)                                                                                                                                            
  7. Do not let the water run in vain unnecessarily when you wash yourself and avoid too strong jets of water.                                                                                                                                                                  
  8. Do not cover the radiators with curtains or other objects.                                                                            
  9. Use electrical devices only for required time.                                                                                                  
  10. Do not leave electronic devices in stand-by, unplug the appliance.                                                                   




  • Photovoltaic panels
  • Electric cables
  • Inverter


Our class, with a Girasole company technician Mr. PIETRAGALLA Michele, experimented the method the photovoltaic panels are mounted by.

Initially, after having unloaded the material from the van, we placed the panels near each other and oriented towards the sun at the same angle, so that no shadows were created between them. Then we put the panels in communication with each other by connecting the positive pole of each of them to the negative pole of the next one, thus obtaining a block which in turn was connected to an inverter: an electronic device able to convert the continuous current input into alternating current output and to change the amplitude and frequency parameters.

And wonder of wonders, we understood how a photovoltaic panel can be really installed, and light was!!!



  • Photovoltaic panels
  • Electric cables
  • Inverter


Our class, with a Girasole company technician Mr. PIETRAGALLA Michele, experimented the method the photovoltaic panels mounted by.

Initially, after having unloaded the material from the van, we placed the panels near each other and oriented towards the sun at the same angle, so that no shadows created between them. Then we put the panels in communication with each other by connecting the positive pole of each of them to the negative pole of the next one, thus obtaining a block which in turn connected to an inverter: an electronic device able to convert the current continuous input into alternating current output and to change the amplitude and frequency parameters.

And wonder of wonders, we understood how a photovoltaic panel really installed, and light has been!!

Photovoltaic installation

In our path of work-school alternation we have collaborated with the “Girasole” green economy company and with Ing. Giambattista scocuzzo who taught us from the basics, how to install a photovoltaic system giving us all the necessary instructions, following us step by step.

To do all this, you must first complete a form with a whole series of data.

To start, you have to take all the data of the customer to mount the system, then personal data and customer type, or if the customer is a private individual, public body or for a company.

Then we move on to the type of installation, whether it is a building or a piece of land.

In the case of the building, it is necessary to indicate whether it is a flat roof or a pitched roof and specify the presence of a balustrade. If instead it is a land, you must indicate whether it is flat, sloping or terrace. Obviously we must refer to the type of roof that the building has, so if the roof is 1 or more pitches or if it is flat and specify the shape and type of tiles

Logistic information is very important. It is necessary to know if the installation site is in a limited traffic area and if the area has the road of sufficient size for access and for maneuvers and possibly list possible problems for unloading. You also need to know the installation area: whether it is in an urban area, on the outskirts, in an agricultural area or in an area free of obstacles and of course the region.

The most important part is to indicate the electrical characteristics of the system to be installed.

It is necessary to specify: Supply, position, inverter space contactor, technical compartment position, distances between inverter, generator and general panel and make sure that everything is in accordance with the law.

Finally, a map is drawn where there must be all the useful information for the engineer.

We class 4E have simulated the installation of the system on our school and each of us has compiled their own card with all the information useful to our school with the help and directions of the engineer. Giambattista Scocuzzo and Raffaele Cambriglia company manager.

It was a really useful and interesting experience.

Photovoltaic fields

The heat pump

The heat pump is a thermal machine that can transfer thermal energy from a source to a lower temperature to a higher temperature source, using different forms of energy, generally electrical.

The operation of the heat pumps is equal to the operation of a refrigerator. With the difference that the refrigerator cycle is inverted. The principle is simple: From a source of natural heat (geothermal, water, air) heat is absorbed to use it for heating. A heat pump heating system consists of three elements: energy-source plant, heat pump, distribution plant and accumulator.

Principle of operating a heat pump:

1: A thermal fluid transports thermal energy

The thermal fluid circulates inside a closed circuit and has the task of carrying and transmitting thermal energy.

You wonder where does the energy gain so typical of heat pumps come from? – The answer is simple: from the evaporator!

2: The thermal fluid evaporates in the evaporator

The name of the evaporator derives from the fact that the liquid coolant fluid boils, in other words evaporates inside it at very low temperatures and in the meantime absorbs energy from the environment.

The coolant fluid is thus in a gaseous state.

3: Under pressure the gas will heat up

At this point the coolant is compressed into the compressor and decreases its volume. During this process the pressure increases and consequently the temperature of the coolant fluid. The coolant fluid circulates to the condenser.

This is an exchanger in which the energy absorbed by the environment is transmitted to the heating system.

4: The coolant cools down and absorbs heat again

In the cooling process, the heat transfer fluid flows to the liquid state. The expansion valve decreases the pressure and

the fluid absorbs heat energy from the environment again.

The cycle then starts again.


The first advantage is undoubtedly the energy efficiency, which as mentioned is high. This makes the geothermal heat pump cost-effective even in the face of greater gas cost than electricity. The economic benefits of the heat pump are bigger than the more expensive and the more energy-efficient the plants to be replaced (those with fossil fuels such as diesel and LPG for example).

A well-designed and installed geothermal system in the right conditions saves billing for about 40% of total energy consumption expenditure (if the plant is equipped with a separate counter). The combination of the heat pump to a radiant heating and cooling system guarantees energy savings of 40% to 70% compared to traditional systems. From the environmental point of view, however, the heat pump with heating function increases the use of renewable energy and thereby reduces climatic emissions.

A heat pump user is guaranteed at least the comfort of classical combustion systems, as well as unprecedented economic and energy savings and a more modern and eco-friendly home.


Those who build apartments or houses should consider the fact that a heat pump, consuming less energy than a traditional system, automatically improves the energy class of buildings, paving the way for a property revaluation and privileged access to local incentives Or national targets in an ecologically viable zero impact.


Finally, heat pump installers can finally create a unique heating, cooling and hot water plant for healthcare, thus providing greater comfort and lower operating costs.

Moreover, the goal of the European community is to be taken into account: by 2020, by 2020, reduce energy consumption and CO2 emissions by replacing them with completely renewable and clean energy.

In this sense, heat pumps will definitely be able to contribute, as renewable heat sources, with 60% energy efficiency compared to conventional combustion systems and no CO2 emissions at the site where they are installed.

Whenever possible, it is always advisable to install a heat pump system to replace traditional heating; This way, it is possible to eliminate combustion and achieve a higher safety standard when gas line connections or gas storage facilities are not needed, such as LPG or diesel fuel, but a simple electrical connection.

A heat pump is ultimately easy to install and is therefore an ideal solution also during the renovation of houses or flats; In these cases, problems related to the availability of space or other structural constraints (especially evident in historical centers) can be more easily resolved.

Summarizing, the two main advantages associated with heat pump heating systems are:


A heat pump is a really flexible heating system that can be tailored to individual needs each time.


A heat pump is characterized by a high energy yield; Thanks to it it is able to present lower operating costs than conventional heating systems (such as autonomous systems, electric stoves, gas stoves, pellet stoves, etc.); In addition, a heat pump can be conveniently installed in either new-built homes or in existing or refurbished dwellings.

If we want to go further, a clear indicator of the convenience of a heat pump compared to a classic system is the so-called Time Backed Time (TBA), ie the time needed to match the savings (resulting from the resulting low running costs of a pump Heat) and the initial surplus.


What it is

The Sun is the source of solar energy produced using directly the rays arriving on Earth.

Solar Energy Source

The sun, a large sphere of incandescent gas, has got a much hotter surface than the Earth and for this reason it is similar to a huge thermal power plant.

The solar energy comes from the union of very small elementary particles, called protons, which constitute the majority of the mass of the sun. The protons, in continuous movement because of the high temperatures to which they are subjected, collide with each other, producing helium, a light gas, and a lot of energy. A part of it is transformed into light energy and is transmitted in space, but only a small quantity comes to us.

How it is exploited

The intermittent nature of solar radiation as an energy source makes indispensable the use of storage devices of the energy produced during the hour and favourable periods. The energy of solar rays can be used to produce electric power, through photovoltaic cells, or to produce heat, through solar panels.

The photovoltaic cells

The photovoltaic cells are very thin sheets of silicon which, affected by sunlight, generate electric power that can be directly used, they can only be used to power small appliances, since they have not great efficiency.

Solar panels

The photovoltaic panels are constituted by a kind of box with a sheet of glass positioned on the front surface and a black sheet positioned on the lower one. Between the two sheets there is a coil in which water circulates in the majority of cases and, only in a few cases, air. The glass lets the light filter; this one, then, is captured and converted into heat by the black surface. The heat cannot escape from the glass, so it heats the water that circulates in the coil and then it is put into a heating system. The cost of such a facility is quite high: a lot of panels are necessary to heat enough water and, in addition, the panels work well only in very sunny areas.

Environmental impact

Solar energy, like other renewable sources, is a clean energy, because its use is perfectly integrated into the natural cycles. Although some environmental effects are well visible, it does not produce polluting emissions and does not alter the environmental balances of our Earth.

Our Beautiful Country and the Photovoltaics

Uses and purposes of the technologies employed to harness solar energy
One of our main tasks to incorporate the alternative resources in order to protect our planet for generations to come. The solar energy is also an alternative to reduce the cost of electrical energy and it is a good resource because it can be used in different ways.
Different techniques for the use of solar energy have been developed in the corse of history, for example, for cooking, melting metals and even for war purposes (you have only to think of Archimedes’s burning glasses). However, the use of fossil fuels (gas, oil, coal) has prevailed in the modern era; all these are nothing more than solar energy by living organisms over millions of years and ready to use at any time.
The awareness of the relative scarcity of fossil fuels and the sensitivity towards their effects on the climate and the environment, as well as an adequate technological development, have led to search the uses solar radiation to replace fossil fuels, at least in part, for energy ends.
A first classification can follow the criterion the technological uses of solar radiation, that is of the ends they pursue.  

We can, thus, have:
• solar thermal which includes the technologies to get low and average temperature heat for the production of sanitary hot water, for the summer and winter air-conditioning of environments, for cooking (solar furnaces), for water treatment (desalination) and for some industrial processes (drying, ageing, etc.);
• solar power, whose technologies are aimed at the production of electrical energy in a direct way (photovoltaic, thermoelectric Seebeck effect) or by means of the heat collection at high temperature and its conversion with thermodynamic cycles (Rankine, Stirling).
• solar chemistry which includes different technologies for the utilization of solar energy as a driving force for chemical reactions aiming at the production of fuels, purification treatments or other industrial processes.
Finally, we can mention the exploitation of passive solar and natural light with technologies related to architecture which, beginning  from the first human experiences ( you have only to think of the Igloo or African huts with roofs of banana lives ) have become and more sophisticated.

 Italy: the first in the world for the use of solar energy, now covers 8% of requirements
The Snapshot of Global Photovoltaic Markets report sais that global production capacity of Photovoltaics in treased by 50 GW (gigawatts) in 2015, reaching at least 227 GW. The strongest growth was in China, with 15.3 gigawatts more in 2015, followed by Japan (11 GW), the USA (7 GW), the  EU (7 GW) and India (2 GW). The Asia-Pacific region alone accounts for 59% of the global solar energy market. After Italy, Greece and Germany the countries that use photovoltaics more are Belgium and Japan (around 4%), followed by Bulgaria, the Czech Republic and Australia (around 3.5%). China is the 21st, with only 1% of its requirements covered by the sun. Worse still the USA, at the 25th place with less than 1%.
These data confirm a strong position of our country in the field of clean energy. The main effort was made particularly in a period between 2007 and 2012 and renewable energies had the highest electricity production performance in 2014 (43%), when we had a historical record in the field of geothermal energy. Besides, at beginning of the referendum on the drills, the government has said that it to cover with renewable energies the 50% of electricity needs.
The commitment has been applied more to fossil fuels and less to renewable energies that are not properly supported. In fact, the retroactive cuts of Renzi’s government to the incentives and renewable energies appeared in Decree about “Competitiveness” and contributed to weaken investors’ interests in Italy last year. The consequence of this is that Italy is losing positions in the ranking globally pointing to new energy markets, after pulling the sprint in the most difficult moment, when costs were higher and yields lower.

Energy sources

The energy is actually a secondary energy source. This means that we get electricity through the conversion of other sources of energy, such as coal, nuclear, wind power or solar energy. These are called primary sources. The energy sources we use to make electricity can be non-renewable or renewable. The four most common non-renewable energy sources are oil and petroleum products, natural gas, coal and uranium. Non-renewable energy sources come out of the ground as liquids, gases, and solids. Petroleum is the only commercial non-renewable fuel that is naturally in liquid form. Natural gas and propane are normally gases, and coal is a solid. Coal, petroleum, natural gas, and propane are all considered fossil fuels because they were formed from the buried remains of plants and animals that lived millions of years ago. Renewable energy sources can be replenished.  The five most common renewable sources are biomass, water, geothermal energy, wind and solar energy. Unlike fossil fuels, non-biomass renewable sources of energy do not directly emit greenhouse gases. Power transmission in a country is generally done through a grid system, which supplies a whole country from a small number of very large and highly effective power stations. In power stations huge turbine generators transform mechanical energy into electric power. Turbines can be driven by different energy sources.

Here are the main types:


Thermoelectric Turbines are driven by the steam produced by the combustion of fossil fuels.
Nuclear Turbines are driven by the steam produced by the heat generated by the nuclear fission of 235-uranium.
Geothermal These power stations exploit the energy produced by underground steam.
Hydroelectric Turbines are driven by the kinetic energy of water collected in the reservoirs or by the movement of ocean tides and river falls.
Wind Power is produced by aerogenerators which harness the kinetic energy of wind.
Solar Special plates which exploit solar energy and transform it into electricity.


Renewable Energies

Renewable energies are energy sources whose use does not damage the natural resources available to man. The rate of regeneration of these resources is so high that, despite the continuous demand for energy, their quantity remains nearly unchanged and therefore they can be considered inexhaustible. Some renewable sources are available in large quantities and are not affected by their exploitation from man. A typical example of renewable energy is wind power.

Other renewable sources, however, can run out when man exaggerates the use of them. These sources are called exhaustible renewable energies. For example, wood is a renewable resource, because some trees are cut while others begin to grow. However, if the number of cut trees is higher than those that grow, there will be a progressive reduction of the forest in the course of time, until it completely disappears. In this second case, the excessive exploitation has transformed a renewable resource in an exhautible resource.

The main renewable resources

Solar power

It is the best known renewable source and is used to produce heat and, thanks to photovoltaic technology, to produce electricity.

Wind energy

It can be transformed directly into mechanical energy and indirectly into electric energy. Wind energy is one of the oldest sources of renewable energy. It has been the only source of energy for sea transport over long distances since millennia.


They are organic resources that can be used as fuels. For example, the inferior quality stuff from the agro-food processing can be used as raw material to produce thermal energy by combustion. Some organic substances can be transformed into biofuels.


It is the energy of the Earth and the heat coming from the subsoil. The temperature increases in hearthly depths. In some areas the thermic difference among the surface and the underground layers is greater and can be exploited to heat and create a motion of natural circulation of liquids.


It is the movement of water masses. The main sources of hydroelectric energy are generated by the natural cycle of water, by waves and tides.

The fossil energy sources and nuclear source are, however, considered to be of limited resources and non-renewable given that regenerate naturally through a much longer cycle compared to renewable ones.

Consumption of Primary Sources in Italy in 2004

To meet the energy demand millions of tonnes oil equivalent, on average 185 Mtoe, were consumed in Italy in 2004 by using various primary sources. The amounts of energy used for each primary source are specified in the following table:

Primary sources used in 2004








Nuclear (Mtoe) Total
97,046 58,128 13,305 12,601 4,120 185,200
52,4% 31,4% 7,2% 6,8% 2,2% 100%



What is the geothermal energy?

Geothermal energy is a form of exploitable and renewable energy , if used in a short time ,which is derived from the heat present in the deeper layers of the earth’s crust, where the temperature increases on average of about 30 ° C for km. The deposits of this energy, however, are dispersed and in depth so high as to prevent the exploitation. Therefore,in order to extract and use the heat trapped in the Earth, it is necessary to identify the areas where it is concentrated.

What advantages can we take of this energy?

The use of this energy has advantages as the inexhaustibility in short times, if it is exploited in a rational way, and less pollution of the surrounding environment,  as it is possible the presence of ​​toxic elements in the area, such as sulfur, mercury and arsenic contained in geothermal fluids. For this reason  these geothermal areas are subjected to annual environmental checks.

What are the disadvantages?

Among the several disadvantages, the main ones are:

  • The typacal unpleasant smell of rotten eggs of thermal springs caused by hydrogen sulphide also leaks out from geothermal power plants.This is a problem particularly adverse to the resident population in the vicinity of a geothermal power plant and solved by installing special abatement equipment.
  • The external impact of geothermal power plants may cause some landscaping problems. The plant , in fact, seems to be a tangle of typical anti-aesthetic pipes of industrial facilities. This problem can be easily solved by using an architecture that respects the landscape and the common sense of aesthetics.

What is the history of this energy?

Hot springs have been used for bathing since Paleolithic. The oldest known spa is a stone pool in China, built on Lisan Mount during the Qin Dynasty in the third century BC. In the first century AD, the Romans conquered Aquae Sulis, now Bath, in Somerset in England, and used the hot springs to feed public baths and underfloor heating, which probably represent the first commercial use of geothermal energy, although the most ancient geothermal heating system for a neighborhood was installed at Chaudes-Aigues,in France and became operational in the fourteenth century. The first industrial exploitation originated in 1827 with the use of the steam of a geyser to extract the boric acid from a mud volcano, at Larderello, in Italy. Today the United States has reached the position as a world leader in geothermal electricity production and the largest group of geothermal power plants around the world is The Geysers in California. The Philippines is the second largest producer; in fact, the ‘use of such energy constitutes about 27% of its own production of electricity.

What are the available areas to recover it?

Some particular areas may present conditions in which the temperature of the subsoil is higher than the average, a consequence of tectonic or volcanic phenomena. In fact,  energy  can be easily recovered using geothermal energy in these “hot spots”.

How many types of geothermal sources can be?

Geothermal sources can be divided into three types:

  • hydrothermal sources: the source is not too deep (1000-2000 m) and depending on the pressure it can be classified as a geothermal source steam or water-dominant
  • geopressurized sources: the source is located at greater depths (3000-10000 m) and the water contained therein is at high pressures (1000 atm) and at a temperature of 160 ° C
  • petrothermal sources: the source is located at greater depths than the previous ones and is composed of hot rocks (without water). About 85% of geothermal resources are of this type but they are also difficult to use because of the lack of water.