ITBO20110314A1 - COMBINED SYSTEM FOR ENERGY COGENERATION STARTING FROM RENEWABLE SOURCES - Google Patents

Description

â € œCOMBINED PLANT FOR ENERGY COGENERATION FROM RENEWABLE SOURCESâ €

DESCRIPTION OF THE INVENTION

The present invention is part of the technical sector relating to the production of energy starting from renewable sources.

In particular, the present invention relates to a combined plant that uses various renewable natural sources for the direct generation of electrical and thermal energy, and for the production of energy carriers to be used on site or to be supplied to third parties.

It is well known that efficient exploitation of renewable sources for the production of energy that can be used for human activities, in any form, has now become an indispensable requirement to allow sustainable economic and social development, which does not involve the destruction of natural resources and which does not significantly contribute to polluting the atmosphere, water resources and arable land.

In recent decades, various technologies have been created and perfected that currently allow the most common renewable natural energy sources to be used more or less efficiently, namely solar energy, wind energy and energy. mechanics generated by water falls. Considerable progress has also been made in the use of resources of more complex exploitation, such as, for example: the energy of the sea derived from waves, from tidal differences in height or from temperature differences at different depths; the geothermal energy contained in the superheated vapors and gases or in the high temperature water coming from the subsoil; the energy deriving from the biogas produced by the digestion action of the organic compounds present in waste vegetable biomass or in sewage from farms or from the sewage network.

As is well known, the exploitation of each of the aforementioned sources has peculiar advantages and limits, which essentially depend on the type of source itself. For example, you can produce energy from the sun (in the form of solar thermal energy or electricity from photovoltaic systems) only during the day, in variable quantities depending on the time and cloud cover, electricity from the wind when its speed It is included in a useful range, and energy from the waves when the sea is rough or rough.

The production of energy from the aforementioned sources therefore has the characteristic of being highly discontinuous. To ensure an efficient and acceptable use of the same, it is therefore necessary to provide storage systems for the energy produced in the periods in which production exceeds consumption (for example, packs of rechargeable batteries) and, together with these or alternatively, a supply of energy through more conventional sources.

As regards the production of energy from the sun and wind, to allow optimal exploitation of the plants it is preferable to locate them in areas where the particular resources are present in a particularly intense form, such as for wind farms or large solar thermal or photovoltaic plants. , or distribute them patchy throughout the territory (mainly small solar thermal or photovoltaic systems), taking advantage of the possibility of finding unused surfaces and using the energy produced directly on site.

In any case, conventional plants for the production of energy from renewable sources are designed and located in such a way as to make the most of a particular natural resource present in a specific site. It is therefore clear that the availability curve of the energy produced by the plant depends on the trend of the availability of the relative resource; this also implies that, when the power available from the natural resource is lacking or becomes insufficient, it is necessary to resort to conventional sources for the uses normally supplied by that plant.

For known production plants this occurs for a good percentage of the time (usually, from 30% in wind installations to 50-60% in solar installations, depending on the seasons and climatic conditions).

It is also true that the energy produced in these plants is generally of a single type, for which the same plants are foreseen. Thus, for example, a photovoltaic system, a wind power plant or a hydroelectric plant will only supply electricity, while a solar thermal system will only supply hot water.

One purpose of the present invention is to propose a combined plant for the cogeneration of energy starting from renewable natural sources capable of making the most of all the energy resources present in a given site.

A further purpose of the invention is to propose a cogeneration plant capable of supplying different types of energy or energy carrier.

Another purpose of the invention is to propose a configuration of a cogeneration plant in which the various sources contribute to guaranteeing the maximum continuity of supply of the energy produced.

Another object of the invention is to propose a cogeneration plant with a compact structure and relatively little invasive of the site in which it is located.

The aforementioned purposes are entirely achieved, in accordance with the content of the claims, by a combined plant for the cogeneration of energy intended to be installed in a site where there is a plurality of renewable energy resources to be exploited.

The combined plant includes an anaerobic biodigester suitable for processing sewage and other biodegradable organic material to produce combustible gas; this in turn comprises a digestion tank, inlet and outlet conduits for the material and agitating means for the same inside the digestion tank. A wind turbine is also provided, arranged above the biodigester and comprising a plurality of wind turbines designed to rotate a drive shaft to produce mechanical energy, and to operate the agitator means and an electric generator. The plant also includes a photovoltaic type solar generator, intended to produce electricity, placed above the biodigester and below the wind generator. An insulated tank is also provided, designed to contain water to be heated and connected to a hot water distribution system. The system also includes a solar thermal generator, located below the wind turbine and above the biodigester, and connected to a heat exchanger placed inside the tank to heat the water contained inside. internal.

The plant also includes a conventional cogeneration unit, intended to be activated in the event of insufficient production of solar or wind electricity or thermal energy, and a storage-production-distribution unit of gas, intended to receive gas produced by the biodigester and from the public gas network to power the cogenerator.

The characteristics of the invention, as will appear from the claims, are highlighted in the following detailed description, with reference to the attached drawing tables, in which:

Figure 1 schematically illustrates a configuration of a combined cogeneration plant made according to the present invention;

Figure 2 illustrates a block diagram of the configuration of a combined cogeneration plant according to a first embodiment of the invention.

A combined plant for the cogeneration of energy realized according to a first embodiment of the invention is indicated with 100 with reference to figure 1, in which a preferred arrangement of the different components is schematically illustrated, and to figure 2, in which instead, the interactions between the various components are illustrated in the form of a block diagram.

As will be better detailed below, plant 100 comprises a plurality of interacting energy generation, storage or use units. Although each of the aforementioned generating units may have a rather complex structure, the technology underlying the operation of each of them is fully known and does not present aspects that directly affect the present invention. These units will therefore be described, for reasons of simplicity of presentation, in their most general terms, and only those aspects relating to the respective interactions in this combined plant 100 will be detailed.

Plant 100 is intended to be installed in any site where there is a plurality of renewable energy resources to be exploited.

In particular, the combined plant 100 comprises an anaerobic biodigester 10, intended to process sewage and other biodegradable organic waste material to produce combustible gas, typically methane. The biodigester 10 can therefore be fed with sewage from sewers, animal waste from farms of all sizes, vegetable waste of agricultural origin, etc.

The biodigester 10 comprises a digestion tank 11, preferably buried in correspondence with the installation site of the combined plant 100 and provided with inlet 12 and outlet 13 ducts for the material to be processed, operating for example according to the known technology of the digester to loop.

Inside the tank 11 there are agitator means 14 for the material itself, substantially constituted by a plurality of paddles 15 keyed on a vertical shaft 16 and able to be rotated to mix the contents of the tank 11 and facilitate the digestion phases anaerobic. The operating modes of the vanes 15 will be better detailed later, as well as the destination of the natural gas produced by digestion.

The combined plant 100 also provides for a wind turbine 20, intended to exploit the wind to produce rotational mechanical energy. The wind turbine 20 is arranged above ground above the biodigester 10 and comprises a plurality of wind turbines 21 and a drive shaft 22 rotatably supported in a substantially vertical position. In particular, in the embodiment illustrated in the figure, the drive shaft 22 is mounted in axis with the vertical shaft 15 of the agitator means 14 of the biodigester 10. In this way the rotational mechanical energy produced by the action of the wind on the wind turbines 21, or at least part of it, is immediately used without wastes and drops in yield to mix the material being treated in the biodigester 10.

Since usually the energy produced by the wind turbine 20 is somewhat greater than that necessary for the operation described above, the crankshaft 22 is also connected, by means of a mechanical motion transmission device 23, to an electrical generator 30, capable of transforming the excess mechanical energy from the wind turbine 20 into electrical energy.

The generator 30, in turn, is electrically connected to an electrical distribution unit 40, by means of a connection indicated with â € œAâ € in the figures, destined to receive all the electricity produced in the combined plant 100, at distribute it to the intended uses in the same plant, and to introduce the excess production into the network.

The combined plant 100 also includes a photovoltaic type solar generator 50, intended to directly convert solar energy into electrical energy and to transfer it to the aforementioned distribution unit 40 by means of a connection indicated with the reference â € œDâ € in the figures.

According to the invention, the photovoltaic generator 50 is composed of a plurality of panels organized in a structure having an approximately paraboloid shape, or in any case having a concave active surface 51 suitable for reflecting the solar radiation which it does not absorb for the production of energy , and in particular infrared radiation, in the direction of its own axis of symmetry.

In the embodiment illustrated, the photovoltaic generator 50 is also arranged above ground, above the biodigester 10 and below the wind turbines 21 of the wind turbine 20, with the drive shaft of the latter substantially in axis with the symmetry axis of the photovoltaic generator 50 itself.

Immediately above the photovoltaic generator 50, the combined system 100 provides for an additional solar generator 70, of the thermal type, capable of exploiting solar radiation to produce thermal energy. In particular, the heat generator 70 comprises a plurality of panels arranged obliquely and converging towards each other upwards. Preferably, the same generator has a pyramidal or truncated cone shape, with the broken vertex facing the other, has a vertical axis substantially coinciding with the aforementioned axis of the photovoltaic generator 50 and with the motor shaft 22 of the wind turbine 20 and it is positioned in such a way as to advantageously collect, in addition to direct solar radiation, also the infrared radiation reflected by the active surface 51 of the same photovoltaic generator 50.

The structure described above of the solar thermal generator 70 allows it to define a large space 73 inside, suitable for housing further components of the combined plant, as will be evident in the following description. For example, in the space 73 the above described electric generator 30 is housed, as illustrated in Figure 1.

In particular, inside space 73 there is an insulated tank 60, suitable for containing water to be heated and connected, by means of an outlet duct 61, to a hot water distribution system leaving the plant combined 100. The outgoing hot water is compensated by the cold water inlet from an inlet duct 61, and regulated by known level control means, not shown.

The above described solar thermal generator 70, in this regard, is suitably placed in fluid connection with a heat exchanger 71 arranged inside the tank 60, so as to transfer the water contained in the latter to the water contained in the latter. € ™ thermal energy produced. In figure 1 the heat exchanger 71 has been reproduced split, so as to serve the two opposite halves of the heat generator 70 separately and more efficiently.

Inside space 73, the combined plant 100 includes a conventional cogeneration unit 80, intended to be activated in the event of insufficient production of solar or wind electricity or thermal energy, to produce electricity in turn and thermal to forward to uses. The cogeneration unit 80 comprises an internal combustion engine, powered by natural gas, hydrogen or both fuels, and a corresponding electric generator, capable of exploiting the mechanical energy produced by the aforementioned engine to generate electricity and transfer it to the distribution unit 40 described above, with a connection indicated with the reference â € œBâ € in the figures.

The cogeneration unit 80 also comprises a first heat exchanger 81, arranged inside the tank 60 and able to transfer the cooling heat of the internal combustion engine to the water contained therein; the structure of this first heat exchanger is typically the forced circulation one normally used in the aforementioned motors, with a recirculation pump mechanically operated by the same motor.

The conventional cogeneration unit 80 also advantageously comprises a second heat exchanger 82, arranged inside the tank 60 and able to transfer part of the residual heat contained in the engine exhaust gases to the water. A third heat exchanger 83 is also provided, arranged inside the biodigester 10 and able to transfer to the material contained therein the residual heat present in the exhaust gases of the same engine, not used in the second exchanger 82.

In fact, the anaerobic digestion function that takes place inside the biodigester 10 takes advantage of even modest increases in the temperature of the material, such as those that can provide the aforementioned residual heat present in the exhaust gases before they are conveyed towards the ™ external.

The combined plant 100 also provides for a gas storage-production-distribution unit 90, whose functions are manifold. In particular, this unit 90 is intended to receive and store the gas produced by the biodigester 10, through a connection indicated with the reference â € œG1â € in the figures, and to make it available for the operation of the cogeneration unit 80 when necessary. In addition, an arrival terminal G2 of the public gas network is optionally connected to unit 90, intended to make up for any insufficient production by the biodigester 10.

The unit 90 can also be equipped with a known device for the on-site production of combustible gas, for example a carbide gasometer.

In any case, unit 90 is intended to supply the cogeneration unit 80 with all the gas necessary for its operation, preferably using that produced by the biodigester 20 and, alternatively, that produced on site or from the public network. of gas.

A particularly advantageous aspect that can be deduced from what has been described for the structure of the combined plant 100 lies in the fact that the same provides a configuration of the various components substantially in a pyramid shape, with the structure having an enlarged base and which gradually narrows towards the € ™ high. In this structure the photovoltaic generator 50 provides that its concave active surface consisting of photovoltaic panels is arranged at the base of the same pyramid, and oriented upwards. The solar thermal generator 70 has a plurality of solar panels, with natural or preferably forced circulation, arranged oblique and converging towards the top and is positioned in correspondence with the central part of the photovoltaic generator 50, and contextually defines in the central area of the Plant 100 a large space 73. The wind turbine 20 is arranged with its shaft 22 vertical in correspondence with the central axis of the pyramid and the underground biodigester 10 is placed immediately below the base of the pyramid, with the shaft of the agitator means 14 arranged in axis with the drive shaft 22 of the wind turbine 20. The tank 60, the electric generator 30 and the conventional cogeneration unit 80 are arranged inside the aforementioned space 73 defined by the generator solar thermal 70.

This configuration is extremely compact, minimizes the environmental impact of the system 100 and also optimizes the performance of some of its components, such as the photovoltaic generator 50, the heat generator 70 and the functions for maintaining the temperature of the tank water 60.

According to a further advantageous result of the aforementioned system configuration, the shaft 22 of the wind turbine 20 passes inside the tank 60, to release part of the mechanical energy to the water contained therein and increase the temperature due to the viscous drag effect. This also entails that the water in the tank 60 simultaneously acts as a brake of the wind turbine 20 itself in the event of too strong winds, preventing the wind turbines 21 from rotating too quickly and being damaged.

Depending on the particular needs of the site of use, for example in the event that an injection connection to the electricity grid is not available, the combined plant 100 can comprise means of generating hydrogen 110, together with a corresponding storage plant, which they are not illustrated for simplicity. As universally known, hydrogen is one of the most sought after and attractive energy carriers, both for the high density of energy it contains, and because the conversion into other forms of energy more immediately usable, such as energy electricity or thermal energy, takes place in an absolutely clean way and not harmful to the environment.

The production of hydrogen can take place in electrolysis starting from the electricity distributed by the distributor 40. In this particular case, the hydrogen produced can be used in combination or as an alternative to gas to power the engine of the aforementioned cogeneration unit 80 .

In the event that a water fall of sufficient flow is present near the installation site, the combined plant 100 can also advantageously provide a hydroelectric unit 120, for example placed underground near the biodigester 10. The hydroelectric unit 120 comprises a turbine 121 and a hydroelectric generator 122 mechanically connected thereto. The electricity produced by the aforementioned generator 122 is also intended to be sent for use, with a connection indicated with the reference â € œCâ € in the figures, through the aforementioned distributor 40.

A second embodiment of the invention provides that within the combined plant 100 the distribution of the mechanical energy produced takes place hydraulically. In this case, a single suitably sized electric generator is provided, driven by a single hydraulic motor. The drive energy of the hydraulic motor, consisting of a circulation of hydraulic fluid with suitable characteristics at high pressure, is supplied by a plurality of hydraulic pumps, each driven by a respective generator of mechanical energy. In particular, the hydraulic pumps will be driven by the wind turbine 20, by the internal combustion engine of the conventional cogenerator 80 and possibly by the hydraulic turbine 121, if the combined plant 10 also includes the hydroelectric unit 120.

The construction details deriving from the aforementioned second embodiment of the invention, which include the structure of the different hydraulic pumps and the hydraulic motor, as well as the hydraulic circuits and the connecting components, are not illustrated and will not be further explored, in virtue of their belonging to the average knowledge of any plumbing system designer appointed to collaborate in the construction of the combined system 100.

An obvious advantage offered by the invention is that of bringing together, in a single compact and extremely minimally invasive plant, the efficient and synergistic exploitation of all the natural energy resources that any site can offer, integrating it with the minimum production of energy with traditional means sufficient to guarantee a constant supply of electrical and thermal energy for a community or for an agricultural, artisan or industrial complex. Alternatively, the combined plant 100 can simply operate as a clean and environmentally sustainable power plant that guarantees a constant injection of electrical and thermal energy into the related public distribution networks.

It is understood that the above has been described purely by way of non-limiting example. Therefore, possible modifications and variants of the invention are considered to fall within the protective scope accorded to the present technical solution, as described above and claimed hereinafter.

Claims (10)

CLAIMS 1. Combined plant for the cogeneration of energy, said plant 100 being intended to be installed in a site where there is a plurality of renewable energy resources to be exploited, characterized by the fact that it includes: at least one anaerobic biodigester 10 suitable for processing sewage and other biodegradable organic material for producing combustible gas, comprising a digestion tank 11, inlet 12 and outlet 13 conduits of said material, and agitator means 14 of the same inside said digestion tank 11; at least one wind turbine 20, arranged above said biodigester 10 and comprising a plurality of wind turbines 21 suitable to rotate a drive shaft 22 to produce mechanical energy, the latter being in turn adapted to actuate the aforementioned agitator means 14 and, with the excess mechanical energy, to drive an electric generator 30 to produce electric energy and convey it to an electric distribution unit 40; at least one solar generator of the photovoltaic type 50, intended to produce electrical energy and transfer it to said distribution unit 40, said photovoltaic generator 40 being arranged above the aforementioned biodigester 10 and below the aforementioned wind generator 20; an insulated tank 60, suitable for containing water to be heated and connected, by means of an outlet duct 61, to a hot water distribution system, control means being provided to compensate for the water delivered through an inlet duct 62 ; a solar generator of the thermal type 70, arranged below the aforementioned wind generator 20 and above the aforementioned biodigester 10, said heat generator 70 being placed in fluid connection with a heat exchanger 71 arranged inside the aforementioned tank 60 to heat it the water contained inside; a conventional cogeneration unit 80, intended to be activated in the event of insufficient production of solar or wind electric or thermal energy, comprising an internal combustion engine and an electric generator, capable of exploiting the mechanical energy produced by said engine to generate electricity and transfer it to the aforementioned distribution unit 40, and also comprising a first heat exchanger 81, arranged inside the aforementioned tank 60 and able to transfer the cooling heat of the engine to the water contained therein ; a gas storage-production-distribution unit 90, intended to receive gas produced by the aforementioned biodigester 10 and from the public gas network to power the aforementioned cogenerator 80. 2. Combined plant for the cogeneration of energy according to claim 1, characterized in that it provides a substantially pyramid-like configuration of the various components, in which said photovoltaic generator 50 comprises a surface of panels arranged at the base of the same pyramid and oriented towards the High, said solar thermal generator 70 has a plurality of panels arranged oblique and converging towards the top and is positioned in correspondence with the central part of said photovoltaic generator 50, said wind generator 20 is arranged with its shaft 22 vertical in correspondence of the central axis of said pyramid and with said biodigester 10 underground and placed immediately below the aforementioned photovoltaic generator 50, with the shaft of the aforementioned agitator means 14 arranged in axis with said shaft 22 of the wind generator 20 and directly connected, with said tank 60, said electric generator 30 and said unit of cogeneration 80 being arranged inside the space 73 defined by the internal part of the aforementioned solar thermal generator 70. 3. Combined plant for the cogeneration of energy according to claim 1, characterized in that said conventional cogeneration unit 80 also comprises a second heat exchanger 82, arranged inside the aforementioned tank 60 and able to transfer to the water part of the residual heat of the engine exhaust gases and a third heat exchanger 83, arranged inside the aforementioned biodigester 10 and able to transfer to the material contained therein the residual heat present in the exhaust gases of the engine of the aforementioned system cogeneration 80. 4. Combined plant for the cogeneration of energy according to claim 1, characterized by the fact that the shaft 22 of the aforementioned wind generator 20 passes inside the aforementioned tank 60, to transfer part of the mechanical energy to the water in contained and increase the temperature due to the viscous drag effect, and at the same time operate as a brake of the wind generator itself in the case of too strong winds. 5. Combined plant for the cogeneration of energy according to claim 1, characterized by the fact that the aforementioned photovoltaic generator 50 is shaped like a paraboloid, and by the fact that the solar thermal generator 70 is shaped like a truncated cone and has the its axis substantially coincides with the axis of the aforementioned photovoltaic generator 50. 6. Combined plant for the cogeneration of energy according to claim 1 or claim 5, characterized by the fact that said solar thermal generator 70 contains inside the aforementioned tank 60, with the shaft 22 of the aforementioned wind generator 20 centered on the axis of the same photovoltaic generator 50, and also contains inside the electric generator 30 and the conventional cogenerator 80. 7. Combined plant for the cogeneration of energy according to claim 1, characterized in that the aforementioned gas storage-production-distribution unit 90 also provides a carbide gas generator, intended to generate gas on site independently in case insufficient supply by the aforementioned biodigester and / or temporary unavailability of the network gas supply. 8. Combined plant for the cogeneration of energy according to claim 1, characterized in that it further comprises generating means of hydrogen 110 for electrolysis starting from the electrical energy distributed by the aforementioned distributor 40, said hydrogen being usable as an alternative to gas to feed the engine of the aforementioned cogeneration unit 80. 9. Combined plant for the cogeneration of energy according to claim 1, characterized in that a hydroelectric unit 120 is also provided, comprising a turbine 121 and a hydroelectric generator 122 mechanically connected to it, the energy produced by said generator 122 being also sent for use through the aforementioned distributor 40. 10. Combined plant for the cogeneration of energy according to claim 1, characterized by the fact that the distribution of mechanical energy takes place hydraulically, by means of hydraulic pumps that drive a single hydraulic motor, which in turn drives a single electric generator .