System for the partially converting the chemical energy included in an electrolytic solution into electrical energy, process actuatable by said system and electrolytic solution supplied to said system

Abstract

The invention relates to a system for converting, at least partially and without combustion, into electrical energy of chemical energy included in an electrolytic solution, being also a subject of the invention, comprising copper hydroxide, potassium hydroxide, ethanol with an alcohol content greater than 90% and double-distilled water. The system (1) comprises an electrolytic cell (3) for subjecting the aforesaid electrolytic solution to electrolysis, and a fuel cell (25) for producing electrical energy from the aeriform mixture generating in the electrolytic cell (3). A further solution (26), also electrolytic, exits from the fuel cell (25) and is re-introduced into the electrolytic cell (3) by means of the passage through a recovery tank (28). The invention further relates to a process, also actuatable by means of the aforesaid system (1), for converting, at least partially and without combustion, into electrical energy the chemical energy included in the aforesaid electrolytic solution.

Description

[0001] System for the partially converting into electrical energy the chemical energy included in an electrolytic solution, process actuatable by said system and electrolytic solution feedable to said system for partially converting into electrical energy the chemical energy included therein

[0002] Field of application of the invention

[0003] The present invention finds application in the field of energy and concerns, in particular, systems suitable for converting, at least partially, chemical energy into electrical energy without resorting to combustion.

[0004] Overview of the prior art

[0005] The systems for at least partial conversion of chemical energy into electrical energy which do not resort to combustion are known. Among this type of system, which can be qualified as "electrochemical", the most common are electric accumulators and fuel cells.

[0006] Objects of the invention

[0007] The object of the present invention is to indicate a system for converting, at least partially and without combustion, chemical energy into electrical energy, which forms an alternative to the known systems of the same type. Another object of the present invention is to indicate both a process actuatable by the aforesaid system, and a liquid usable in said system so as to convert at least part of the chemical energy included in said liquid into electrical energy.

[0008] Summary and advantages of the invention

[0009] A subject of the present invention is an electrolytic solution (and therefore a liquid) including:

[0010] • copper hydroxide for a percentage by weight between 3% and 7%;

[0011] • potassium hydroxide for a percentage by weight between 35% and 75%;

[0012] • ethanol with an alcohol content greater than 90% for a percentage by weight between 10% and 30%;

[0013] • double-distilled water for a percentage by weight between 10% and 45%.

[0014] A person skilled in the art is capable of preparing an electrolytic solution including the above-listed components in the amounts indicated above. Therefore, further details will not be provided regarding the preparation of the aforesaid solution. Another subject of the present invention is a system for converting, at least partially and without combustion, into electrical energy the chemical energy included in the electrolytic solution of the invention, said system comprising:

[0015] • an electrolytic cell including:

[0016] - a tank comprising: at least one wall delimiting, at least partially, a cavity at which said tank is suitable for housing said electrolytic solution; at least one access opening to said cavity;

[0017] - an electrical voltage generator;

[0018] - at least one pair of electrodes, each electrode of said pair being housed in said cavity at least at a portion thereof, each electrode of said pair being made of steel and / or titanium and / or tungsten at least at said portion, said generator being connected to the electrodes of said pair so as to be suitable for applying an electrical voltage thereto, said generator, when said electrolytic solution is housed in said cavity in an amount such that each electrode of said pair is submerged in said electrolytic solution at least at part of said portion, being also suitable for applying an electrical voltage to the electrodes of said pair such as to subject said electrolytic solution to electrolysis, with consequent formation in said cavity of an aeriform mixture including hydrogen, oxygen and nitrogen, and tending to exit said cavity through said opening, said wall of said tank being suitable for conducting, away from said cavity, heat when generating inside said cavity by electrolysis of said electrolytic solution;

[0019] • a first pressure sensor suitable for detecting the absolute pressure of said aeriform mixture when forming in said cavity;

[0020] • first control means connected to both said first sensor and to said generator, said first control means being suitable for operating said generator (i.e., for adjusting the electrical voltage applicable by said generator to the electrodes of said pair) so that, when said electrolytic solution is housed in said cavity in an amount such that each electrode of said pair is submerged in said electrolytic solution at least at part of said portion, the electrolysis of said electrolytic solution takes place and the absolute pressure of said aeriform mixture generated inside said cavity for electrolysis of said electrolytic solution is kept below a first limit value without however falling below a second limit value lower than said first limit value;

[0021] • a second temperature sensor suitable for detecting the temperature of said electrolytic solution when housed in said cavity;

[0022] • cooling means suitable for:

[0023] - subtracting, at least in part, heat from said wall when conducted by the same away from said cavity (following a generation of said heat inside said cavity by electrolysis of said electrolytic solution), and for

[0024] - expelling, at least in part, from said heat system when subtracted from said wall;

[0025] • second control means connected to both said second sensor and to said cooling means, said second control means being suitable for operating said cooling means, when said electrolytic solution is housed in said cavity, every time the temperature of said electrolytic solution is equal to or greater than a third limit value, so as to cool said electrolytic solution sufficiently that the temperature of said electrolytic solution falls below said third limit value without, however, falling below a fourth limit value lower than said third limit value;

[0026] • a hydrogen and oxygen PEM-type fuel cell, said fuel cell comprising:

[0027] - at least one anode;

[0028] - at least one cathode;

[0029] - at least one proton exchange membrane interposed between said anode and said cathode, said fuel cell being connected to said tank at said opening so that said aeriform mixture, when generating in said cavity by electrolysis of said electrolyt- ic solution, tends to flow from said cavity into said fuel cell, feeding the latter so that:

[0030] - at least part of the hydrogen included in said aeriform mixture reaches said anode and

[0031] - at least part of the oxygen included in said aeriform mixture reaches said cathode, so that said fuel cell is suitable for:

[0032] - converting at least partially into electrical energy the chemical energy included in said aeriform mixture and coming from said electrolytic solution and for

[0033] - outputting therefrom an "additional" solution, also electrolytic, and forming simultaneously with an at least partial conversion into electrical energy of the chemical energy included in said aeriform mixture and coming from said electrolytic solution, said fuel cell being active, so as to at least partially convert into electrical energy the chemical energy included in said aeriform mixture when entering said fuel cell, if the hydrogen concentration in said aeriform mixture is greater than a predetermined limit concentration, said fuel cell being active, so as to at least partially convert into electrical energy the chemical energy included in said aeriform mixture when entering said fuel cell even if the hydrogen and nitrogen concentration in said aeriform mixture is overall greater than said predetermined limit concentration (so that the fuel cell therefore considers nitrogen as if it were hydrogen), regardless of whether or not the concentration of hydrogen alone in said aeriform mixture is greater than said predetermined limit concentration.

[0034] To avoid any misunderstanding, a person skilled in the art is capable of modifying the electronics of a common hydrogen and oxygen PEM-type fuel cell so that the fuel cell is active if the concentration of hydrogen and nitrogen in the aeriform mixture fed to the fuel cell is overall greater than the aforesaid predetermined limit concentration, regardless of whether or not the concentration of hydrogen alone is greater than the aforesaid predetermined limit concentration. By way of explanation, to obtain the aforesaid result, it is necessary to intervene on the fuel cell firmware so as to significantly increase the electrostatic cycles of the cell FCU in the unit of time, for example from 300 per second to 500 per second;

[0035] • filtering means, said fuel cell being connected to said tank with the interposition of said filtering means so that said aeriform mixture, when formed in said cavity by electrolysis of said electrolytic solution, can reach said fuel cell only by passing through said filtering means, said filtering means being suitable for preventing, at least partially, the transit towards said fuel cell of aeriform mixture possibly condensed after exiting from said cavity;

[0036] • a recovery tank, said fuel cell being connected to said recovery tank so as to introduce said additional electrolytic solution therein when dispensed by said fuel cell simultaneously with an at least partial conversion into electrical energy of the chemical energy included in said aeriform mixture and coming from said electrolytic solution, said filtering means being also connected to said recovery tank so as to introduce into the same aeriform mixture possibly condensed after exiting from said cavity and the transit of which towards said fuel cell has been prevented by said filtering means, said recovery tank therefore being suitable for housing an "additional" electrolytic solution therein and comprising:

[0037] - said aeriform mixture possibly condensed after exiting from said cavity and the transit of which towards said fuel cell has been prevented by said filtering means and

[0038] - said additional electrolytic solution when dispensed by said fuel cell simultaneously with an at least partial conversion into electrical energy of the chemical energy included in said aeriform mixture and coming from said electrolytic solution; • separating means, said fuel cell being connected to said recovery tank with the interposition of said separating means so that said additional electrolytic solution, when dispensed by said fuel cell simultaneously with an at least partial conversion into electrical energy of the chemical energy included in said aeriform mixture and coming from said electrolytic solution, can reach said recovery tank only by passing through said separating means, said separating means being suitable for:

[0039] - preventing air possibly contained in said recovery tank from coming into contact with said fuel cell and consequently for

[0040] - allowing said additional electrolytic solution, when dispensed by said fuel cell simultaneously with an at least partial conversion into electrical energy of the chemical energy included in said aeriform mixture and coming from said electrolytic solution, to enter said recovery tank without air possibly contained in the latter reaching said fuel cell;

[0041] • first pumping means connected to said recovery tank and to said tank of said electrolytic cell, said first pumping means being suitable for introducing said additional electrolytic solution in said cavity when housed in said recovery tank, adding it to said electrolytic solution when present therein, so as to give rise to a "further" solution, also electrolytic and, to an electrolysis of the latter by means of said electrolytic cell, to a further aeriform mixture tending to flow in said fuel for feeding the latter;

[0042] • a third level sensor suitable for detecting the level of said electrolytic solution, or of said further electrolytic solution, in said cavity when said electrolytic solution, or said further electrolytic solution, is housed in said cavity;

[0043] • third control means connected to both said third sensor and to said first pumping means, said third control means being suitable for operating said first pumping means, when said electrolytic solution, or said further electrolytic solution, is housed in said cavity and every time the level of said electrolytic solution, or of said further electrolytic solution, in said cavity is lower than a fifth limit value, so as to introduce said additional electrolytic solution in said cavity sufficiently so that the level of said further electrolytic solution in said cavity reaches or exceeds said fifth limit value but does not exceed a sixth limit value, greater than said fifth limit value.

[0044] Other innovative features of the present invention are disclosed in the following description and mentioned in the dependent claims.

[0045] According to an aspect of the invention, said cooling means comprise:

[0046] • a coating wall enveloping said tank at least at part of said wall thereof, and so that between said wall of said tank and said coating wall there is a gap crossable by a fluid (for example water), said fluid, at a crossing of said gap, being suitable for subtracting, at least in part, heat from said wall of said tank when conducted by the same away from said cavity (following a generation of said heat inside said cavity by electrolysis of said electrolytic solution);

[0047] • a heat exchanger crossable by said fluid and by a further fluid not comprised in said system, said heat exchanger being connected to said gap so as to form a circuit along which said fluid can:

[0048] - enter said gap;

[0049] - cross said gap (flowing, at least partially, around said wall of said tank);

[0050] - exit from said gap and enter said heat exchanger;

[0051] - cross said heat exchanger;

[0052] - exit from said heat exchanger and re-enter said gap, said heat exchanger being such that said fluid, upon crossing said heat exchanger, transfers, at least in part, heat to said further fluid when subtracted from said wall of said tank, so as to expel from said system, at least in part, said heat subtracted from said wall;

[0053] • second pumping means suitable for circulating said fluid along said circuit, said second control means being connected to said second pumping means and being suitable for operating the latter, an actuation of said second pumping means corresponding to an actuation of said cooling means.

[0054] The aforesaid further fluid could correspond to water intended to become domestic hot water, or water intended to flow in a heating system.

[0055] According to another aspect of the invention, said filtering means comprise a container connected to both said tank and said fuel cell so that said aeriform mixture, when formed in said cavity by electrolysis of said electrolytic solution, can reach said fuel cell only by passing through said container, said container being connected to said tank, and being shaped so that, said aeriform mixture, when formed in said cavity by electrolysis of said electrolytic solution, flows through said container following a path including a descending section followed by an ascending section so that at least part of the aeriform mixture possibly condensed after exiting from said cavity cannot completely travel said ascending section and consequently remains housed in said container (thus without being able to reach said fuel cell), said container being connected to said recovery tank:

[0056] • at a portion thereof (of said container) where aeriform mixture possibly condensed after exiting from said cavity and remained housed in said container tends to accumulate,

[0057] • so that aeriform mixture possibly condensed after exiting from said cavity and accumulating in said portion of said container tends to flow into said recovery tank, entering the same.

[0058] According to another aspect of the invention, said system comprises an expansion vessel, said fuel cell being connected to said tank also with the interposition of said expansion vessel so that said aeriform mixture, when formed in said cavity by electrolysis of said electrolytic solution, can reach said fuel cell only by passing through said filtering means and said expansion vessel, said expansion vessel being suitable for absorbing, at least partially, pressure changes of said aeriform mixture when formed in said cavity by electrolysis of said electrolytic solution.

[0059] Another object of the present invention is a process for converting, at least partially and without combustion, into electrical energy the chemical energy includ- ed in the electrolytic solution of the invention, said process comprising the following steps: a) producing the electrolytic solution of the invention and preparing the system of the invention by setting:

[0060] • as said first and second pressure limit values 55 kPa and 45 kPa, respectively;

[0061] • as said third and fourth temperature limit values 95 C and 45°C, respectively;

[0062] • as said fifth level limit value a value such that, when the level of said electrolytic solution, or of said further electrolytic solution, in said cavity corresponds to said fifth limit value, said cavity (of said tank of said electrolytic cell) is occupied by said electrolytic solution, or by said further electrolytic solution, for a percentage of the volume thereof between 50% and 65%;

[0063] • as said sixth level limit value a value such that, when the level of said electrolytic solution, or of said further electrolytic solution, in said cavity corresponds to said sixth limit value, said cavity (of said tank of said electrolytic cell) is occupied by said electrolytic solution, or by said further electrolytic solution, for a percentage of the volume thereof comprised between 66% and 80%.

[0064] Incidentally, it is not necessary to set the aforementioned "predetermined limit concentration" (forming a constraint for the operation of the fuel cell) since it is implicitly set by the fuel cell manufacturer according to the parameters of the latter; b) introducing said electrolytic solution into said cavity in an amount such that each electrode of said pair is submerged in said electrolytic solution at least at part of said portion; c) operating said first, second and third control means and said fuel cell so that:

[0065] • said generator, by means of the electrodes of said pair, subjects said electrolytic solution to electrolysis and subsequently said further electrolytic solution and the absolute pressure of said aeriform mixture, and subsequently of said further aeriform mixture, generated by electrolysis from said electrolytic solution, or from said further electrolytic solution, is maintained below said first limit value but without falling below said second limit value;

[0066] • the temperature of said electrolytic solution, or of said further electrolytic solution, is maintained by said cooling means below said third limit value but without falling below said fourth limit value;

[0067] • said fuel cell, if the hydrogen concentration in said aeriform mixture, or in said further aeriform mixture, entering said fuel cell is greater than said predetermined limit concentration, or if the concentration of hydrogen and nitrogen in said aeriform mixture, or in said further aeriform mixture, entering said fuel cell is overall greater than said predetermined limit concentration, converts at least partially into electrical energy the chemical energy included in said aeriform mixture, or in said further aeriform mixture, entering said fuel cell;

[0068] • the level of said electrolytic solution, or of said further electrolytic solution, in said cavity is maintained by said first pumping means equal to or greater than said fifth limit value without, however, exceeding said sixth limit value.

[0069] Advantageously, by actuating the process of the invention using the system of the invention and the electrolytic solution of the invention, the electrical energy which is dispensed by the fuel cell of the system of the invention is greater than that consumed overall by the generator of the electrolytic cell, by the fuel cell, by the separating means, by the pumping means and by the control means. Brief description of the drawings

[0070] Further objects and advantages of the present invention will become clear from the following detailed description of embodiment examples thereof and from the accompanying drawing (Figure 1 ) given purely by way of non-limiting explanation, and diagrammatically showing a system according to the present invention for converting, at least partially and without combustion, into electrical energy the chemical energy included in the electrolytic solution of the invention.

[0071] The scale and proportions of the various depicted elements do not necessarily correspond to the real ones. Detailed description of preferred embodiments of the invention

[0072] Figure 1 shows, diagrammatically, a system 1 of the invention for converting, at least partially and without combustion, into electrical energy the chemical energy included in an electrolytic solution 2. The latter, also being a subject of the invention, comprises copper hydroxide for a percentage by weight between 3% and 7%, potassium hydroxide for a percentage by weight between 35% and 75%, ethanol with an alcohol content greater than 90% for a percentage by weight between 10% and 30% and double-distilled water for a percentage by weight between 10% and 45%.

[0073] The system 1 comprises an electrolytic cell 3 including a tank 4 comprising one or more walls delimiting, at least partially, a cavity 6 at which the tank 4 is suitable for housing the solution 2. The tank 4 further comprises an opening 7 for access to the cavity 6. The tank 4 is, by way of explanation, substantially shaped as a rectangular parallelepiped and therefore comprises four side walls 5 arranged vertically in the figure, a first base 8 arranged below in the figure and a second base 9 arranged above in the figure. The walls 5 and the bases 8 and 9 (also corresponding to walls of the tank 4) delimit, at least partially, the cavity 6. The opening 7 is preferably made in the base 9. The tank 4 is preferably made of AISI 316 steel. The cavity 6 preferably has a volume of four liters.

[0074] The electrolytic cell 3 comprises at least one pair of electrodes connected to an electrical voltage generator 10 suitable for applying an electrical voltage thereto. Regarding the aforesaid pair of electrodes, the anode, on the left in the figure, is marked by reference numeral 11 and the cathode, on the right in the figure, is marked by reference numeral 12. Each of the electrodes 11 and 12 passes through the base 9 so as to lie inside the tank 4 (and therefore so as to be housed in the cavity 6) at least at a portion thereof. Each of the electrodes 11 and 12 is, at least at the aforesaid portion and preferably completely, made of steel and / or titanium and / or tungsten.

[0075] When an amount of electrolytic solution 2 is housed in the cavity 6 such that each of the electrodes 11 and 12 is submerged in the electrolytic solution 2 at least at part of the aforesaid portion (as shown in the figure), the generator 10 is suitable for applying an electrical voltage (for example of 8 V) to the electrodes 11 and 12 such as to subject the electrolytic solution 2 to electrolysis, with the consequent formation of an aeriform mixture 13 in the cavity 6 (diagrammatical- ly shown in the figure for the sake of simplicity by bubbles) including hydrogen, oxygen and nitrogen, and tending to exit from the cavity 6 (and consequently from the tank 4) through the opening 7. The aeriform mixture 13 is advantageously free of organic species.

[0076] Incidentally, and as visible in the figure, to subject the electrolytic solution 2 to electrolysis, the cavity 6 is only partially filled with the electrolytic solution 2 so that the aeriform mixture 13 can be generated in the upper portion of the cavity 6 not occupied by the electrolytic solution 2. Preferably, at full capacity, the cavity 6 is occupied by the electrolytic solution 2 or, as will be illustrated in the following of the present description, by a further electrolytic solution 34, for a percentage of the volume thereof preferably between 50% and 80%.

[0077] The system 1 comprises a pressure sensor 14, suitable for detecting the absolute pressure of the aeriform mixture 13 when it is formed in the cavity 6. The sensor 14 is connected to a first control unit 15 which adjusts the electrical voltage applied by the generator 10 to the electrodes 1 1 and 12. More precisely, the control unit 15 is suitable for operating the generator 10 so that, when the electrolytic solution 2 is housed in the cavity 6 in such an amount so that each of the electrodes 11 and 12 is submerged in the electrolytic solution 2 at least at part of the aforementioned portion thereof, the electrolysis of the electrolytic solution 2 takes place and the absolute pressure of the aeriform mixture 13 generated by electrolysis of the electrolytic solution 2 is maintained below a first limit value without however falling below a second limit value lower than the aforesaid first limit value. 55 kPa and 45 kPa are preferably set as the first and second pressure limit values, respectively. Incidentally, the control unit 15 is connected, in addition to the sensor 14, to the generator 10. Again incidentally, the system 1 , after having introduced an appropriate amount of electrolytic solution 2 into the cavity 6, is hermetically closed. For this reason, the absolute pressure of the aeriform mixture 13 can be maintained below atmospheric pressure by the control unit 15.

[0078] The electrolysis of the electrolytic solution 2 releases heat which is conducted (i.e., transmitted by thermal conduction) from the walls 5 and from the bases 8 and 9 of the tank 4 away from the cavity 6. The temperature of the electrolytic solution 2 is preferably maintained between 45°C and 95°C by a cooling system 16 suitable for subtracting, at least in part, heat from the walls 5 and the bases 8 and 9 when conducted by the same away from the cavity 6 (following a generation of said heat inside the cavity 6 by electrolysis of the electrolytic solution 2), and to expel heat, at least in part, from the system 1 when subtracted from the walls 5 and from the bases 8 and 9. The system 1 also comprises a temperature sensor 17, suitable for detecting the temperature of the electrolytic solution 2 when housed in the cavity 6 and connected to a second control unit 18 which controls the cooling system 16. More precisely, the control unit 18 is suitable for operating the cooling system 16 so that, when the electrolytic solution 2 is housed in the cavity 6 in an amount so that each of the electrodes 11 and 12 is submerged in the electrolytic solution 2 at least at part of the aforementioned portion thereof, every time the temperature of the electrolytic solution 2 is equal to or greater than a third limit value, the electrolytic solution 2 is cooled sufficiently so that the temperature thereof falls below a third limit value, but without however falling below a fourth limit value lower than the aforesaid third limit value. Consequently to what was previously mentioned, 95°C and 45°C are preferably set as the third and fourth temperature limit values, respectively. Incidentally, the control unit 18 is connected, in addition to the sensor 17, to the cooling system 16.

[0079] Preferably, the cooling system 16 comprises a coating wall 19 enveloping the tank 4 at least at part of the walls 5 and of the bases 8 and 9, and preferably completely. The wall 19 envelops the tank 4 so that between the tank 4 (i.e., the walls and the bases thereof) and the wall 19 there is a gap 20 that can be crossed by a fluid 21 , preferably consisting of water. The fluid 21 , at a crossing of the gap 20, is suitable for subtracting, at least in part, heat from the walls 5 and the bases 8 and 9 of the tank 4 when conducted by the same away from the cavity 6 (following a generation of heat inside the cavity 6 by electrolysis of the electrolytic solution 2). The cooling system 16 preferably also comprises a heat exchanger 22 crossable by the fluid 21 and by a further fluid 23 not forming part of the system 1 and corresponding, by way of explanation, to water intended to become domestic hot water, or water intended to flow in a heating system. The heat exchanger 22 is connected to the gap 20 so as to form a circuit, travelling along which the fluid 21 can enter the gap 20, cross the latter (flowing, at least partially, around the tank 4), exit from the gap 20, enter the heat exchanger 22, cross the latter, exit the heat exchanger 22 and re-enter the gap 20. At a crossing of the heat exchanger 22, the fluid 21 transfers, at least in part, heat to the further fluid 23 when subtracted from the walls 5 and the bases 8 and 9 of the tank 4, so as to expel, at least in part, said heat from the system 1 . A pump 24, falling within the aforementioned "second pumping means", circulates the fluid 21 along the aforesaid circuit. The control unit 18 is connected to the pump 24 and controls the actuation of the latter. Incidentally, an actuation of the pump 24 corresponds to an actuation of the cooling system 16.

[0080] The system 1 also comprises a hydrogen and oxygen PEM-type fuel cell 25. The fuel cell 25 comprises at least one anode, at least one cathode and at least one proton exchange membrane interposed between the anode and the cathode of the fuel cell 25. Preferably and similarly to the known fuel cells of the same type, the fuel cell 25 comprises multiple pairs, each of which including an anode and a cathode, and multiple proton exchange membranes respectively interposed between the anodes and the cathodes of the aforesaid pairs. The fuel cell 25 is hermetically connected to the tank 4 at the opening 7 so that the aeriform mixture 13, when generating in the cavity 6 by electrolysis of the electrolytic solution 2, tends to flow from the tank 4 into the fuel cell 25, feeding the latter so that at least part of the hydrogen included in the aeriform mixture 13 reaches the anodes of the fuel cell 25 and at least part of the oxygen included in the aeriform mixture 13 reaches the cathodes of the fuel cell 25, so that the latter is suitable for converting at least partially into electrical energy the chemical energy included in the aeriform mixture 13 and coming from the electrolytic solution 2, and to output an "additional" solution 26 also electrolytic and simultaneously forming during an at least partial conversion into electrical energy of the chemical energy included in the aeriform mixture 13 and coming from the electrolytic solution 2. The fuel cell 25 is active, so as to at least partially convert into electrical energy the chemical energy included in the aeriform mixture 13 when entering the fuel cell 25 if the concentration of hydrogen in the aeriform mixture 13 is greater than a predetermined limit concentration. With respect to the known fuel cells of the same type, the fuel cell 25 has been modified so that the fuel cell 25 is active, so as to at least partially convert into electrical energy the chemical energy included in the aeriform mixture 13 when entering the fuel cell 25, not only if the hydrogen concentration in the aeriform mixture 13 is greater than the aforesaid predetermined limit concentration, but also if the concentration of hydrogen and nitrogen in the aeriform mixture 13 when entering the fuel cell 25 is overall greater than the aforesaid predetermined limit concentration (regardless of whether or not the concentration of only hydrogen in the aeriform mixture 13 is greater than the aforesaid predetermined limit concentration).

[0081] The fuel cell 25 is preferably connected to an electrical energy accumulator 27 for storing the electrical energy, in which the chemical energy included in the aeriform mixture 13 and coming from the electrolytic solution 2 is partially converted.

[0082] The generator 10, the control units 15 and 18, the pump 24 and also the fuel cell 25 itself are preferably connected to the accumulator 27 for a powering thereof.

[0083] The system 1 comprises a recovery tank 28 to which the fuel cell 25 is connected so as to introduce the additional electrolytic solution 26 therein, when dispensed from the fuel cell 25 simultaneously with a conversion at least partially into electrical energy of the chemical energy included in the aeriform mixture 13 and coming from the electrolytic solution 2.

[0084] As can be seen in the figure, the fuel cell 25 is connected to the tank 4 with the interposition of an anti-condensation filter 29 and preferably also of an expansion vessel 30, so that the aeriform mixture 13, when formed in the cavity 6 by electrolysis of the electrolytic solution 2, can reach the fuel cell 25 only by passing through the filter 29 and, if present, the expansion vessel 30. Incidentally, the expansion vessel 30 is suitable for absorbing, at least partially, pressure changes of the aeriform mixture 13.

[0085] The filter 29 is suitable for preventing, at least partially, the transit towards the fuel cell 25 of aeriform mixture 13 possible condensed after exiting from the cavity 6. The filter 29 preferably comprises a container 31 connected to both the tank 4 and the fuel cell 25 so that the aeriform mixture 13, when formed in the cavity 6 by electrolysis of the electrolytic solution 2, can reach the fuel cell 25 only by passing through the container 31. The container 31 is connected to the tank 4 and is shaped so that the aeriform mixture 13, when formed in the cavity 6 by electrolysis of the electrolytic solution 2, flows through the container 31 following a path including at least one descending section followed by an ascending section so that at least part of the aeriform mixture 13 possibly condensed after exiting from the cavity 6 cannot completely travel the aforesaid ascending section and consequently remains housed in the container 31 (thus without being able to reach the fuel cell 25). The container 31 is connected to the recovery tank 28 at a portion thereof (of the container 31 ) where aeriform mixture 13, possibly condensed after exiting from the cavity 6 and remained housed in the container 31 , tends to accumulate. The container 31 is connected to the recovery tank 28 also so that aeriform mixture 13 possibly condensed after exiting from the cavity 6 and accumulated in the aforesaid portion of the container 31 (and therefore the transit of which towards the fuel cell 25 has been prevented by the filter 29) tends to flow into the recovery tank 28 entering the same.

[0086] In light of the foregoing, the recovery tank 28 is suitable for housing an “additional" solution 32, also electrolytic and comprising aeriform mixture 13 which has possibly condensed after exiting from the cavity 6 and the transit of which towards the fuel cell 25 has been prevented by the filter 29, and additional electrolytic solution 26 when dispensed by the fuel cell 25 simultaneously with an at least partial conversion into electrical energy of the chemical energy included in the aeriform mixture 13 and coming from the electrolytic solution 2.

[0087] Again as can be seen in the figure, the fuel cell 25 is connected to the recovery tank 28 with the interposition of a device 38, so that the additional electrolytic solution 26, when dispensed from the fuel cell 25 simultaneously with an at least partial conversion into electrical energy of the chemical energy included in the aeriform mixture 13 and coming from the electrolytic solution 2, can reach the recovery tank 28 only by passing through the device 38. The latter compris- es an air separator so as to prevent air possibly contained in the recovery tank 28 from coming into contact with the fuel cell 25, expelling the air outside the system 1 . More precisely, the device 38 is suitable for allowing the additional electrolytic solution 26, when dispensed by the fuel cell 25 simultaneously with an at least partial conversion into electrical energy of the chemical energy included in the aeriform mixture 13 and coming from the electrolytic solution 2, to enter the recovery tank 28 without air possibly contained in the latter being able to reach the fuel cell 25. The device 38 preferably comprises a tank in which the additional electrolytic solution 26 exiting the fuel cell 25 precipitates. The tank of the device 38 is connected to the recovery tank 28 to allow the additional electrolytic solution 26 to flow from the device 38 into the recovery tank 28. Preferably, a solenoid valve controlled by a level sensor adjusts the emptying of the tank of the device 38: upon the additional electrolytic solution 26 reaching a limit level inside the tank of the device 38, an opening of the aforesaid solenoid valve takes place and consequently a transfer of additional electrolytic solution 26 from the device 38 into the recovery tank 28 without allowing any air possibly contained in the latter to flow into the fuel cell 25 (by virtue of the presence of the air separator).

[0088] The device 38 is preferably connected to the accumulator 27 for a powering thereof.

[0089] The system 1 comprises a pump 33 corresponding to the aforementioned "first pumping means" and connected to both the recovery tank 28 and the tank 4 of the electrolytic cell 3. The pump 33 is suitable for introducing into the cavity 6 of the tank 4 the aforesaid additional electrolytic solution 32 when housed in the recovery tank 28, adding it to the electrolytic solution 2 when present therein, so as to give rise to a further solution 34, also electrolytic, and with an electrolysis of the latter by means of the electrolytic cell 3, to a further aeriform mixture 35 tending to flow into the fuel cell 25 for feeding the latter.

[0090] The system 1 also comprises a third level sensor 36, suitable for detecting the level of electrolytic solution 2, or of the aforesaid further electrolytic solution 34, in the cavity 6 (when the electrolytic solution 2, or the aforesaid further electrolytic solution 34, is housed in the cavity 6) and connected to a third control unit 37 which controls the pump 33. More precisely, the control unit 37 is suitable for operating the pump 33 so that, when the electrolytic solution 2, or the aforesaid further electrolytic solution 34, is housed in the cavity 6, every time the level of the electrolytic solution 2, or of the aforesaid further electrolytic solution 34, in the cavity 6 is lower than a fifth limit value, the additional electrolytic solution 32 is introduced by the pump 33 into the cavity 6 sufficiently so that the level of the further electrolytic solution 34 in the cavity 6 reaches or exceeds the aforesaid fifth limit value but without exceeding a sixth limit value greater than the aforesaid fifth limit value. Preferably, as the fifth level limit value, a value is set such that, when the level of the electrolytic solution 2, or of the further electrolytic solution 34, in the cavity 6 corresponds to the aforesaid fifth limit value, the cavity 6 is occupied by the electrolytic solution 2, or by the further electrolytic solution 34, for a percentage of the volume thereof between 50% and 65%. Preferably, as the sixth level limit value, a value is set such that, when the level of the electrolytic solution 2, or of the further electrolytic solution 34, in the cavity 6 corresponds to the aforesaid sixth limit value, the cavity 6 is occupied by the electrolytic solution 2, or by the further electrolytic solution 34, for a percentage of the volume thereof between 66% and 80%. Incidentally, the control unit 37 is connected, in addition to the sensor 36, to the pump 33. The control unit 37 and the pump 33 are preferably connected to the accumulator 27 for a powering thereof. Subject of the invention is also a process for converting, at least partially and without combustion, into electrical energy the chemical energy included in the electrolytic solution 2. The process begins with the production of the electrolytic solution 2 and with the preparation of the system 1 by setting as first and second pressure limit values 55 kPa and 45 kPa respectively, as third and fourth temperature limit values 95°C and 45°C respectively, as fifth level limit value a value such that, when the level of the electrolytic solution 2, or of the further electrolytic solution 34, in the cavity 6 corresponds to the fifth limit value, the cavity 6 is occupied by the electrolytic solution 2, or by the further electrolytic solution 34, for a percentage of the volume thereof between 50% and 65%, and as sixth level limit value a value such that, when the level of the electrolytic solution 2, or of the further electrolytic solution 34, in the cavity 6 corresponds to the sixth limit value, the cavity 6 is occupied by the electrolytic solution 2, or by the further electrolytic solution 34, for a percentage of the volume thereof between 66% and 80%.

[0091] The process then involves introducing the electrolytic solution 2, preferably at room temperature, into the cavity 6 in an amount such that each of the electrodes 11 and 12 is submerged in the electrolytic solution 2 at least at part of the aforesaid portion thereof, and operating the control units 15, 18 and 37 and the fuel cell 25, so that:

[0092] • the generator 10, by means of the electrodes 11 and 12, subjects the electrolytic solution 2 and subsequently the further electrolytic solution 34 to electrolysis and the absolute pressure of the aeriform mixture 13, or of the further aeriform mixture 35, generated by electrolysis from the electrolytic solution 2, or from the further electrolytic solution 34, is kept below 55 kPa without however falling below 45 kPa;

[0093] • the temperature of the electrolytic solution 2, or of the further electrolytic solution 34, is kept by the cooling system 16 below 95°C but not below 45°C;

[0094] • the fuel cell 25, if the hydrogen concentration in the aeriform mixture 13, or in the further aeriform mixture 35, entering the fuel cell 25 is greater than the aforementioned predetermined limit concentration, or if the concentration of hydrogen and nitrogen in the aeriform mixture 13, or in the further aeriform mixture 35, entering the fuel cell 25 is overall greater than the aforementioned predetermined limit concentration, at least partially converts into electrical energy the chemical energy included in the aeriform mixture 13, or in the further aeriform mixture 35, entering the fuel cell 25;

[0095] • the level of the electrolytic solution 2, or of the further electrolytic solution 34, in the cavity 6 is maintained by the pump 33 equal to or greater than the aforementioned fifth limit value without, however, exceeding the aforementioned sixth limit value.

[0096] Incidentally, as the process proceeds, further aeriform mixture possibly condensed exiting from the cavity 6 and the electrolytic solution exiting from the fuel cell 25 accumulate in the recovery tank 28, and both are introduced into the cavity 6 to be subjected to electrolysis again to generate again an aeriform mixture with which the fuel cell 25 is feedable, as described above.

[0097] As previously specified, by actuating the process of the invention using the sys- tern 1 and the electrolytic solution 2, the electrical energy which is dispensed by the fuel cell 25 is greater than that consumed overall by the generator 10, by the pumps 24 and 33, by the fuel cell 25, by the device 38 and by the control units 15, 18 and 37.

[0098] Based on the description provided for a preferred embodiment, it is apparent that some changes can be introduced by those skilled in the art without departing from the scope of the invention as defined by the following claims.

Claims

C L A I M S1 . An electrolytic solution (2), characterized in that it includes:• copper hydroxide for a percentage by weight between 3% and 7%;• potassium hydroxide for a percentage by weight between 35% and 75%;• ethanol with an alcohol content greater than 90% for a percentage by weight between 10% and 30%;• double-distilled water for a percentage by weight between 10% and 45%.

2. A system (1 ) for converting, at least partially and without combustion, into electrical energy the chemical energy included in an electrolytic solution (2) according to claim 1 , said system (1 ) being characterized by comprising:• an electrolytic cell (3) including:- a tank (4) comprising: at least one wall (5, 8, 9) delimiting, at least partially, a cavity (6) at which said tank (4) is suitable for housing said electrolytic solution (2); at least one access opening (7) to said cavity (6);- an electrical voltage generator (10);- at least one pair of electrodes (11 , 12), each electrode (11 , 12) of said pair being housed in said cavity (6) at least at a portion thereof, each electrode (11 , 12) of said pair being made of steel and / or titanium and / or tungsten at least at said portion, said generator (10) being connected to the electrodes (11 , 12) of said pair in order to be suitable for applying an electrical voltage thereto, said generator (10), when said electrolytic solution is housed in said cavity (6) in an amount such that each electrode (11 , 12) of said pair is submerged in said electrolytic solution (2) at least at part of said portion, being also suitable for applying an electrical voltage to the electrodes (11 , 12) of said pair such as to subject said electrolytic solution (2) to electrolysis, with consequent formation in said cavity (6) of an aeriform mixture (13) including hydrogen, oxygen and nitrogen, and tending to exit said cavity (6) through said opening (7),said wall (5, 8, 9) of said tank (4) being suitable for conducting, away from said cavity (6), heat when generating inside said cavity (6) by electrolysis of said electrolytic solution (2);• a first pressure sensor (14), suitable for detecting the absolute pressure of said aeriform mixture (13) when forming in said cavity (6);• first control means (15) connected to both said first sensor (14) and said generator (10), said first control means (15) being suitable for operating said generator (10) so that, when said electrolytic solution (2) is housed in said cavity (6) in an amount such that each electrode (11 , 12) of said pair is submerged in said electrolytic solution (2) at least at part of said portion, the electrolysis of said electrolytic solution (2) takes place and the absolute pressure of said aeriform mixture (13) generated inside said cavity (6) for electrolysis of said electrolytic solution is kept below a first limit value without however falling below a second limit value lower than said first limit value;• a second temperature sensor (17) suitable for detecting the temperature of said electrolytic solution (2) when housed in said cavity (6);• cooling means (16) suitable for:- subtracting, at least in part, heat from said wall (5, 8, 9) when conducted by the same away from said cavity (6) and for- expelling, at least in part, heat from said system (1 ) when subtracted from said wall (5, 8, 9);• second control means (18) connected to both said second sensor (17) and to said cooling means (16), said second control means (18) being suitable for operating said cooling means (16), when said electrolytic solution (2) is housed in said cavity (6), every time the temperature of said electrolytic solution (2) is equal to or greater than a third limit value, so as to cool said electrolytic solution (2) sufficiently so that the temperature of said electrolytic solution (2) falls below said third limit value without however falling below a fourth limit value lower than said third limit value;• a hydrogen and oxygen PEM-type fuel cell (25), said fuel cell (25) comprising:- at least one anode;- at least one cathode;- at least one proton exchange membrane interposed between said anode and said cathode, said fuel cell (25) being connected to said tank (4) at said opening (7) so that said aeriform mixture (13), when generated in said cavity (6) by electrolysis of said electrolytic solution (2), tends to flow from said cavity (6) into said fuel cell (25), feeding the latter so that:- at least part of the hydrogen included in said aeriform mixture (13) reaches said anode and- at least part of the oxygen included in said aeriform mixture (13) reaches said cathode, so that said fuel cell (25) is suitable for:- converting at least partially into electrical energy the chemical energy included in said aeriform mixture (13) and coming from said electrolytic solution (2) and for- outputting an "additional" solution (26) therefrom, also electrolytic and forming simultaneously with an at least partial conversion into electrical energy of the chemical energy included in said aeriform mixture (13) and coming from said electrolytic solution (2), said fuel cell (25) being active, so as to at least partially convert into electrical energy the chemical energy included in said aeriform mixture (13) when entering said fuel cell (25), if the hydrogen concentration in said aeriform mixture (13) when entering said fuel cell (25) is greater than a predetermined limit concentration, said fuel cell (25) being active, so as to convert at least partially into electrical energy the chemical energy included in said aeriform mixture (13) when entering said fuel cell (25), even if the concentration of hydrogen and nitrogen insaid aeriform mixture (13) when entering said fuel cell (25) is overall greater than said predetermined limit concentration, regardless of whether or not the concentration of hydrogen alone in said aeriform mixture (13) is greater than said predetermined limit concentration;• filtering means (29), said fuel cell (25) being connected to said tank (4) with the interposition of said filtering means (29) so that said aeriform mixture (13), when formed in said cavity (6) by electrolysis of said electrolytic solution (2), can reach said fuel cell (25) only by passing through said filtering means (29), said filtering means (29) being suitable for preventing, at least partially, the transit towards said fuel cell (25) of aeriform mixture (13) which has possibly condensed after exiting from said cavity (6);• a recovery tank (28), said fuel cell (25) being connected to said recovery tank (28) so as to inject introduce said additional electrolytic solution (26) therein when dispensed by said fuel cell (25) simultaneously with an at least partial conversion into electrical energy of the chemical energy included in said aeriform mixture (13) and coming from said electrolytic solution (2), said filtering means (29) being also connected to said recovery tank (28) so as to introduce into the same aeriform mixture (13) which has possibly condensed after exiting from said cavity (6) and the transit of which towards said fuel cell (25) has been prevented by said filtering means (29), said recovery tank (28) therefore being suitable for housing an "additional" solution (32) therein, also electrolytic and comprising:- said aeriform mixture (13) which has possibly condensed after exiting from said cavity (6) and the transit of which towards said fuel cell (25) has been prevented by said filtering means (29) and- said additional electrolytic solution (26) when dispensed by said fuel cell (25) simultaneously with an at least partial conversion into electrical energy of the chemical energy included in said aeriform mixture (13) and coming from said electrolytic solution (2);• separating means (38), said fuel cell (25) being connected to said recovery tank (28) with the interposition of said separating means (38) so that said additional electrolytic solution (26), when dispensed by said fuel cell (25) simultaneously with an at least partial conversion into electrical energy of the chemical energy included in said aeriform mixture (13) and coming from said electrolytic solution (2), can reach said recovery tank (28) only by passing through said separating means (38), said separating means (38) being suitable for:- preventing air possibly contained in said recovery tank (28) from coming into contact with said fuel cell (25) and consequently for- allowing said additional electrolytic solution (26), when dispensed by said fuel cell (25) simultaneously with an at least partial conversion into electrical energy of the chemical energy included in said aeriform mixture (13) and coming from said electrolytic solution (2), to enter said recovery tank (28) without air possibly contained in the latter reaching said fuel cell (25);• first pumping means (33) connected to said recovery tank (28) and to said tank (4) of said electrolytic cell (3), said first pumping means (33) being suitable for introducing into said cavity (6) said additional electrolytic solution (32) when housed in said recovery tank (28), adding it to said electrolytic solution (2) when present therein, so as to give rise to:- a "further" solution (34), also electrolytic and- to an electrolysis of said further electrolytic solution (34) by means of said electrolytic cell (3), to a further aeriform mixture (35) tending to flow in said fuel cell (25) for feeding the latter;• a third level sensor (36) suitable for detecting the level of said electrolytic solution (2), or of said further electrolytic solution (34), in said cavity (6) when said electrolytic solution (2), or said further electrolytic solution (34), is housed in said cavity (6);• third control means (37) connected to both said third sensor (36) and said first pumping means (33), said third control means (37) being suitable for operating said first pumping means (33), when said electrolytic solution (2), or said further electrolytic solution (34), is housed in said cavity (6) and every time the level of said electrolytic solution (2), or of said further electrolytic solution (34), in said cavity (6) is lower than a fifth limit value, so as to introduce said additional electrolytic solution (32) in said cavity (6) sufficiently so that the level of said further electrolytic solution (34) in said cavity (6) reaches or exceeds said fifth limit value without however exceeding a sixth limit value greater than said fifth limit value.

3. A system (1 ) according to claim 2, characterized in that said cooling means (16) comprise:• a coating wall (19) enveloping said tank (4) at least at part of said wall (5, 8, 9) thereof, and so that between said wall (5, 8, 9) of said tank (4) and said coating wall (19) there is a gap (20) crossable by a fluid (21 ), said fluid (21 ), at a crossing of said gap (20), being suitable for subtracting, at least in part, heat from said wall (5, 8, 9) of said tank (4) when conducted by the same away from said cavity (6);• a heat exchanger (22) crossable by said fluid (21 ) and by a further fluid (23) not comprised in said system (1 ), said heat exchanger (22) being connected to said gap (20) so as to form a circuit along which said fluid (21 ) can:- enter said gap (20);- cross said gap (20);- exit from said gap (20) and enter said heat exchanger (22);- cross said heat exchanger (22);- exit from said heat exchanger (22) and re-enter said gap (20), said heat exchanger (22) being such that said fluid (21 ), upon crossing said heat exchanger (22), transfers, at least in part, heat to said further fluid (23) when subtracted from said wall (5, 8, 9) of said tank (4), so as to expel from said system (1 ), at least in part, said heat subtracted from said wall (5, 8, 9);• second pumping means (24) suitable for circulating said fluid (21 ) along said circuit, said second control means (18) being connected to said second pumping means (24) and being suitable for operating the latter, an actuation of said second pumping means (24) corresponding to an actuation of said cooling means (16).

4. A system (1 ) according to claim 2 or 3, characterized in that said filtering means (29) comprise a container (31 ) connected to both said tank (4) and said fuel cell (25) so that said aeriform mixture (13), when formed in said cavity (6) by electrolysis of said electrolytic solution (2), can reach said fuel cell (25) only by passing through said container (31 ), said container (31 ) being connected to said tank (4) and being shaped so that said aeriform mixture (13), when formed in said cavity (6) by electrolysis of said electrolytic solution (2), flows through said container (31 ) following a path including at least one descending section followed by an ascending section so that at least part of the aeriform mixture (13) possibly condensed after exiting from said cavity (6) cannot completely travel said ascending section and consequently remains housed in said container (31 ), said container (31 ) being connected to said recovery tank (28):• at a portion thereof where aeriform mixture (13), possibly condensed after exiting from said cavity (6) and remained housed in said container (31 ), tends to accumulate,• so that aeriform mixture (13) possibly condensed after exiting from said cavity (6) and accumulating in said portion of said container (31 ) tends to flow into said recovery tank (28) entering the same.

5. A system (1 ) according to one of claims 2 to 4, characterized in that it comprises an expansion vessel (30), said fuel cell (25) being connected to said tank (4) also with the interposition of said expansion vessel (30) so that said aeriform mixture (13), when forming in said cavity (6) by electrolysis of said electrolytic solution (2), can reach said fuel cell (25) only by passing through said filtering means (29) and said expansion vessel (30),said expansion vessel (30) being suitable for absorbing, at least partially, pressure changes of said aeriform mixture (13) when forming in said cavity (6) by electrolysis of said electrolytic solution (2).

6. A process for converting, at least partially and without combustion, into electrical energy the chemical energy included in an electrolytic solution (2) according to claim 1 , said process being characterized by comprising the following steps: a) producing an electrolytic solution (2) according to claim 1 and preparing a system (1 ) according to claim 2, by setting:• as said first and second pressure limit values 55 kPa and 45 kPa, respectively;• as said third and fourth temperature limit values 95 C and 45°C, respectively;• as said fifth level limit value a value such that, when the level of said electrolytic solution (2), or of said further electrolytic solution (34), in said cavity (6) corresponds to said fifth limit value, said cavity (6) is occupied by said electrolytic solution (2), or by said further electrolytic solution (34), for a percentage of the volume thereof between 50% and 65%;• as said sixth level limit value a value such that, when the level of said electrolytic solution (2), or said further electrolytic solution (34), in said cavity (6) corresponds to said sixth limit value, said cavity (6) is occupied by said electrolytic solution (2), or said further electrolytic solution (34), for a percentage of the volume thereof between 66% and 80%; b) introducing said electrolytic solution (2) into said cavity (6) in an amount such that each electrode (11 , 12) of said pair is submerged in said electrolytic solution (2) at least at part of said portion; c) operating said first, second and third control means (15, 18, 37) and said fuel cell (25) so that:• said generator (10), by means of the electrodes (11 , 12) of said pair, subjects said electrolytic solution (2) to electrolysis and subsequently said further electrolytic solution (34)and the absolute pressure of said aeriform mixture (13), and subsequently of said further aeriform mixture (35), generating by electrolysis from said electrolytic solution (2), or from said further electrolytic solution (34), is maintained below said first limit value but without falling below said second limit value;• the temperature of said electrolytic solution (2), or of said further electrolytic solution (34), is maintained by said cooling means (16) below said third limit value but without falling below said fourth limit value;• said fuel cell (25), if the concentration of hydrogen and nitrogen in said aeriform mixture (13), or in said further aeriform mixture (35), entering said fuel cell (25) is overall greater than said predetermined limit concentration, converts at least partially into electrical energy the chemical energy included in said aeriform mixture (13), or in said further aeriform mixture (35), entering said fuel cell (25);• the level of said electrolytic solution (2), or of said further electrolytic solution (34), in said cavity (6) is maintained by said first pumping means (33) equal to or greater than said fifth limit value, without however exceeding said sixth limit value.

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