ES2325848B1 - HYDROGEN AND ELECTRICAL ENERGY PRODUCTION SYSTEM FROM PHOTOVOLTAIC ENERGY. - Google Patents

Abstract

Hydrogen and energy production system Electrical from photovoltaic energy.

It has at least one cell module photovoltaic (1) that feeds an electrolyzer (3) that generates hydrogen and that has hydrogen storage media produced; including at least one fuel cell (2) that allows to generate electricity from hydrogen stored; facilitating improvements in production performance of electrical energy from photovoltaic energy and its availability when hydrogen is used as an energy vector of intermediate storage

Description

Hydrogen and energy production system Electrical from photovoltaic energy.

Object of the invention

The present invention, as expressed in the statement of this specification refers to a system of hydrogen production and electrical energy from photovoltaic energy whose purpose is to facilitate a independent energy source that can be used as a means of sourcing in isolated sites of the distribution networks of commercial electric power, or as a means of support when produce failures in the commercial network; also being facilitated by the invention the improvement in energy production performance electricity from photovoltaic energy and its availability, due to the use of hydrogen as an energy vector of intermediate storage

The main objective of the invention is in facilitating the development of power generation plants Electrical and production, storage and use of hydrogen, making use of what is known as the solar cycle of hydrogen.

Background of the invention

The current energy system is based on the use of fossil hydrocarbons, which has an associated series of problems.

First of all it should be mentioned that it is from a source with limited reserves, and although there is speculation about the duration of these reservations, it is true that they will not reach supply the entire 21st century. On the other hand, combustion of fossil hydrocarbons generates greenhouse gases such as CO2, together with other pollutants such as NOx, SOx that involve a serious threat to Public Health and the Environment. During the Kyoto summit, a global commitment was made to the reduction of greenhouse gas emissions, in special CO2.

This reduction can be undertaken by two Clearly different approaches. On the one hand, developing systems of CO2 sequestration associated with the use of fossil hydrocarbons However, in this approach it remains latent the problem linked to the duration of their reservations. OR well, you can give it another approach, which is the approach of the use of an alternative energy system that is not based on the carbon cycle, so that emissions from pollutants, and on the other hand, that this energy system is sustainable and have a renewable base. To achieve this end, you can use hydrogen, the most abundant element in the nature to be part of the water. However, hydrogen is an energy vector and is not free in nature, for what you need from an energy contribution to obtain it.

On the other hand, in numerous applications it is it is necessary to have electrical power generation systems independent of the commercial supply network, as per example, in isolated telecommunications systems, maintenance of computer networks, any application in which there is no access to the commercial network, or as an independent support system that comes into operation when a network failure occurs commercial distribution Conventionally these problems are solve using diesel or natural gas generators that in some cases are associated with a set of batteries that allow energy storage When the commercial network fails, it starts the diesel generator and the batteries are normally used to supply power to the system while the fault is detected in the commercial network and is put into operation the generator If the generator fails, the batteries They continue to run until downloading occurs.

The expectations of the hydrogen economy are based on the fact that it can be produced from domestic resources, economically and environmentally acceptable. Insofar that these expectations are reached, a hydrogen economy will benefit the world by providing greater energy security and higher environmental quality. Hydrogen and electricity they can become two complementary energy carriers and interchangeable which, depending on the type of energy demand and from the place of final energy supply, may offer minors or zero pollutant emissions (hydrogen and electricity renewable).

The complementarity of hydrogen and electricity is based on the existence of electrolysers, which consuming water and electricity produce hydrogen and oxygen, and of the fuel cells that from hydrogen and oxygen of the Air produce electricity.

The favorable properties of hydrogen for be used as fuel are well known since ancient times: virtually unlimited reserves, complete combustion facility and low level of air pollutants.

On the other hand, there are unfavorable aspects that have prevented the diffusion of the use of hydrogen as fuel: there is no free nature, the traditional schemes of Obtain a negative energy balance throughout the life cycle, as well as a high production cost, and presents a low energy density per unit volume that makes it difficult and makes handling and storage more expensive.

Currently, almost 95% of the world's hydrogen is produced from fossil fuels, mainly by natural gas reforming, and is used as a component that is part of many conventional industrial processes (ammonia, oil refining, methanol, etc. ). It is used around 4% of the hydrogen produced to other transformations of the chemical industry and the rest, is used in vehicle propulsion
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In this sense, it should be emphasized that the Hydrogen is not a resource. Hydrogen is not free in nature, it cannot be accessed by mining or extraction as in fossil fuels. Therefore, if we want to obtain hydrogen, it will necessarily have to be produced from some raw materials (water, hydrocarbons, biomass) and in the process of transformation of these materials to produce hydrogen, we will have to  consume some primary energy (fossil, renewable, nuclear).

One of the most promising methods for produce hydrogen in a clean way from the point of view Environmental is through the Solar hydrogen cycle. In this felt several studies have shown that electrolysis can be use to obtain hydrogen from water using as Electricity source solar energy. The production of hydrogen using direct solar energy can be achieved from Two ways: electric power generation from energy sun thermal and thermolysis; and photovoltaic electrical energy and electrolysis. This second method has the advantage that the generated electrical energy can be applied directly to a electrolyzer

Therefore combining water electrolysis with a fuel cell it is possible to generate electricity at from the water In the electrolyzer the water decomposes to get hydrogen, and this hydrogen is used as fuel in the fuel cell If, in addition, a source of clean energy - solar energy - to generate electricity necessary to carry out the electrolysis of water, the whole of the three systems would allow a clean and inexhaustible source of Energy.

The main components of a reactor electrochemical to carry out water electrolysis are the Separators and electrodes. The separators that can be Use are of three types: diaphragms, polymeric membranes and ceramic membranes

The difference between the different electrolysers to carry out water electrolysis to getting hydrogen will depend on the nature of the electrodes, of the nature of the separator and the type of electrolyte used. Thus, these electrolysers can be divided into several types in function of the type of separator used and of the greater or lesser degree Development reached:

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Alkaline Electrolysers

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PEM type electrolysers.

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Oxide electrolysers solid.

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Alkaline electrolysers refer to that use sodium or potassium hydroxide as an electrolyte, since these solutions pose less corrosion problems than acid solutions. The electrolyte is formed by a solution of the base at concentrations close to 40%, which present the maximum conductivity at the working temperature which is normally of the order of 80ºC.

The cells are built in carbon steel, being cooled by water that dissipates the heat generated. The electrodes are located in two compartments separated by a diaphragm made of ceramic material. The anode material is nickel, while the cathode is usually made of stainless steel. In bipolar cells connect two of them in series through a nickel separator, which makes in an anode cell and in the contiguous cathode, which achieves a significant reduction  in the volume of the device. This process can be carried out at atmospheric pressure or high pressure, of the order of 30 bar with in order to eliminate the compression stage of the gases formed for storage

PEM type electrolysers can operate at low temperatures and pressures. The operation of this type of Electrolysers is inverse to the fuel cell type PEM The advantages of PEM type electrolysers over alkalis focus primarily on using older current densities (referred to the surface of the electrodes) which, together with the reduced membrane thickness (0.25 mm) allows a substantial decrease in the volume of the equipment.

With respect to oxide electrolysers solid, they operate at very high temperatures, of the order of 1000ºC, So electrolysis is carried out on water vapor.

Low temperature electrolysers, alkaline and PEM type are the most suitable for the present invention, using in a preferred design the alkaline electrolysers

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Regarding fuel cells (fuel cells, FC) are electrochemical devices that allow transform the chemical energy contained in the reagents into electrical energy, water and a certain amount of heat. These Electric generators have the following advantages:

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They constitute safe sources of energy and devoid of noise FCs lack moving parts and therefore their Operation is silent. These systems do not use substances corrosive like lead acid batteries which decreases handling risks

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Do not They pollute the environment. The product of the FC reaction that use hydrogen as fuel is water, so these constitute systems with zero emissions of pollutants

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High efficiency (≥ 50%). The efficiency of the FC in the production of electrical energy is higher than that of petrol internal combustion engines and diesel. In batteries that operate at high temperatures (> 600ºC) total efficiency, more electric power generation Heat exceeds 70%.

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Modularity. Depending on the application different devices can be designed sizes.

Different types of batteries are known fuel, such as membrane fuel cells polymeric proton exchange (PEMFC), fuel cells alkaline (AFC), phosphoric acid fuel cells (PAFC), molten carbonate fuel cells (MCFC), batteries Polymeric direct methanol fuel (DMFC) and batteries solid oxides fuel (SOFC). Among these types of batteries fuel, and according to a study of its characteristics, batteries Low temperature fuel (PEMFC, AFC, PAFC) are the most indicated for the present invention, being used in a design preferably those of the PEMFC type.

Fuel cell devices require from a source of hydrogen. The spectacular efficiency boom experienced by fuel cells in the last decade has remarkably driven the accumulation research of H2. This is a problem that far from being trivial has been qualified by the High Level Group for Hydrogen and the Fuel Cells of the European Union as the current neck from bottle to a hydrogen based economy. The solution of the problem of how to accumulate H_ {2} efficiently is, by Therefore, of great importance.

Six different methods of accumulation of H2 are currently investigated:

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Gas compressed.

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H2 liquid.

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Adsorption in high compounds effective surface (activated carbon, zeolites, etc).

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Conventional metal hydrides (LaNi5, Mg)

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Complex hydrides (AlNaH4, NaBH_ {4}, etc)

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Chemical hydrolysis reactions (for example, MgH 2 + 2H 2 O => Mg (OH) 2 + 2H2).

Moreover, solar energy systems photovoltaic convert the energy that comes from the sun directly in electrical energy The simplest and most extended way of harnessing the sun's radiant energy to generate electricity is based on the photovoltaic effect that takes place when the light hits a specially designed device to favor said conversion and called solar cell. So, one solar cell is the element that converts the photons that come of the sun in an electric current that circulates through another element which is called load; being the most efficient solar cells currently solid state devices manufactured with semiconductor materials.

In addition, various types of followers are known solar that improve the performance of solar cells, which they can be applied to the present invention, although at present the vast majority of photovoltaic installations have a fixed orientation throughout the year mainly due to that the energy gain that would involve the use of systems Automatic solar tracking (maximum latitudes and conditions Optimal plots - how much of the territory of Spain -), does not compensate for the cost and complexity that occurs in the Current tracking systems.

Inventions related to the hydrogen production from renewable energies, such as photovoltaic energy; but most of those inventions differ from the present invention in that they focus on achieving a increase in the yield of the energy generated in the plates solar to optimize the hydrogen production of the electrolyzer (see US Patents 20030006136 and ES 2137349). Too we know inventions related to portable systems photovoltaic (ES 1027970) as well as portable integrated systems hydrogen generators from solar energy or through a turbine (US 20060066105).

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We do not know in the current state of the art no energy production system based on a module photovoltaic cells that feed an electrolyzer to produce hydrogen and store it with a stack of batteries fuel for power generation from hydrogen stored, and focused on improving the energy efficiency of the corresponding installation, as the system of the present invention

Description of the invention

To achieve the objectives and avoid drawbacks indicated in previous sections, the invention It consists of a hydrogen and energy production system electrical from photovoltaic energy where energy photovoltaic is obtained with at least one cell module Photovoltaic from solar radiation.

Novelly, according to the invention, said module feeds an electrolyzer that generates hydrogen from of water electrolysis and that has storage facilities of hydrogen produced; including at least one stack of fuel that allows the generation of electrical energy from of stored hydrogen; so that the improvement in the electric energy production performance from energy photovoltaic and its availability, when hydrogen is used as intermediate storage energy vector.

According to a preferred embodiment of the invention, said photovoltaic cell module has A solar tracking device.

According to a preferred embodiment of the invention, the electrolyzer is preferably low temperature (alkaline or PEM).

The referred fuel cells are preferably low temperature (PEMFC, AFC, PAFC).

On the other hand, in the preferred embodiment of the invention, the H 2 storage system is sized  for an autonomy of at least three days.

According to the preferred embodiment of the invention, the system has an additional reserve of hydrogen stored in the form of gas under pressure.

The system of the invention can be realized with Easy portability components, as well as having a control subsystem for monitoring and remote control by an Internet connection or through a local network; being able including sending alarms about system status and / or faults in it through GSM or similar text messages.

According to a preferred embodiment of the invention, the system thereof can be structured in a plant of energy production whose functional blocks consist of that the photovoltaic cell module connect to an inverter DC / AC for conventional energy production or with the electrolyser, generating hydrogen that will be stored and will consume in the fuel cell, generating electricity; feeding that inverter to water pumps and air compressors of the plant, as solenoid valves and flow meters of the they are powered by the photovoltaic module itself through DC / DC converters. The electrolyser is fed by the PV module directly or through DC / DC converters or through a rectifier that connects to the mains conventional or with the photovoltaic module through an inverter DC / AC The connection with the photovoltaic modules or with the network Commercial is done through a photoelectric switch.

With the structure described, the system of the invention has the main advantage that it allows obtain an improvement in the energy efficiency of the corresponding photovoltaic installation guaranteeing the continuous availability of energy.

The invention facilitates integration and optimization of an autonomous-portable system of generation of hydrogen and electricity from an energy renewable as the photovoltaic solar, optimizing the production of hydrogen by electrolysis, and integrating this system with a battery of fuel that allows the stationary generation of electricity, controlling and optimizing consumption. The invention provides a new system that allows solving the current problematic that photovoltaic energy possesses in its discharge to the electricity network, which is considerably destabilized, solving problems of adaptation between the hours of maximum production and hours of consumption, since generally those hours of maximum production coincide with the hours of consumption Valley.

Then, to facilitate a better understanding of this descriptive report and being an integral part of the same, some figures are accompanied in which with character illustrative and not limiting the object of the invention.

Brief description of the figures

Figure 1.- Represents a block diagram functionalities of a hydrogen and energy production system electrical from photovoltaic energy made according to the present invention

Figure 2.- Represents a component scheme which are used in the system of the previous figure 1.

Figure 3.- Represents a flow chart of the system of the previous figures in regard to the hydrogen generation

Figure 4.- Represents a flow chart of the system of figures 1 and 2 as regards the generation Of electricity.

Description of an embodiment of the invention

Following is a description of a example of the invention referring to the above figures.

Thus, the hydrogen production system and of electrical energy from photovoltaic energy of the present example has a module of photovoltaic cells 1 that feeds an electrolyzer 3 capable of generating hydrogen from water electrolysis and it has storage media hydrogen produced, for example in the form of metal hydrides, also including a fuel cell 2 that allows generating Electric power from stored hydrogen.

The system of the present example is structured in an energy production plant whose functional blocks can be seen in figure 1 and that interconnect as seen in said figure and as described below. So, the module of photovoltaic cells 1 connects to a DC / AC inverter 4 to conventional energy production and also to feed the electrolyser for the production of H2 that will be used by the fuel cell to generate electricity.

The referred inverter 4 feeds water pumps 6 and air compressors 7 of the plant, while solenoid valves 8 and flow meters 9 thereof are powered by the photovoltaic module 1 itself through DC / DC converters 5.

On the other hand, the electrolyzer 3 is fed through other DC / DC 5 converters, through the module photovoltaic 1 and through a rectifier 11 that connects to the network conventional electric 12 and with the aforementioned module 1 through a photoelectric switch 10.

Figure 2 shows all the components of the energy production plant of this example, becoming reference to them in a more detailed description that is exposed to continuation.

The plant is autonomous from the point of view of its operation, since during the day the solar panels they provide enough energy to supply the needs for which the plant has been designed, for the obtaining hydrogen through an electrolyzer and for operation of all plant components. In the moments when there is no solar radiation, energy is supplied by the fuel cell that runs on the hydrogen generated from water electrolysis and that is stored, for example, in the form of metal hydrides, having the system (fuel cell-metal hydrides) an autonomy of three days. To guarantee the supply of energy in times of absence of solar radiation or when produce some failure in the solar panel system photovoltaic, there is a reserve of hydrogen stored in form of gas under pressure, whose autonomy can be variable and it will depend on the specific characteristics of the place where it It will implement the plant.

The plant object of the patent is completely portable, which makes it especially applicable for supply electrical power in remote places without access to commercial distribution networks, although it can be used in combination with them.

The plant has a control system that allows its monitoring and remote control through a connection to Internet or a local network based on wimax or similar technology, Depending on availability or not, Internet connection. He sending alarms about the state of the plant or faults in it, it would be done by using text messages via GSM or Similar.

The main source of energy is energy photovoltaic solar that is used during the day to generate the electricity required for the application in question and for feed an electrolyzer that is used to produce hydrogen from the electrolysis of water. Hydrogen produced during the day it is stored and consumed in a fuel cell at times when there is no sunlight, or peaks occur excessive, in energy demand.

The system includes the following components:

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A set of photovoltaic solar panels (MF) that transform the solar energy in electrical energy in the form of direct current (DC) Solar panels can be sized to operate in two shapes. One possibility is to use a part of the set of photovoltaic panels to generate the necessary electrical energy for application consumption through AC conversion using an inverter, and another part of the set would be used to directly feed the electrolyzer, in current Continuous (DC) without going through the inverter. Another possibility, but there is a demand for energy, it is to use the whole set of panels photovoltaic to generate electrical energy that feeds the electrolyzer for the production of hydrogen that is stored and subsequently consumed in a fuel cell, generating electrical energy in the form of direct current (DC) that passes to through an inverter to become alternating current (AC) which supplies the energy demanded by the application particular.

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He photovoltaic field (MF) is formed by a set of panels Photovoltaic connected in series / parallel combinations. Field photovoltaic produces electrical energy in the form of current continuous, from the solar radiation that affects the same.

Each photovoltaic panel generates a voltage and current, at the point of maximum power that depends on the model of panel used. This invention supports the use of any type of crystalline silicon photovoltaic panel, amorphous silicon, organic or other, as long as it allows its interconnection with others in series or in parallel, so that the voltage and current can be adjusted late.

The connection of photovoltaic panels in series or in parallel it allows to increase the voltage or the total current of the photovoltaic field. Thus, when connecting different panels Photovoltaic series generates a voltage that is the sum of the individual voltages of each panel while the current resulting corresponds to that of a single panel of the field photovoltaic When photovoltaic panels are connected in parallel the current resulting from the field, is the sum of the currents individual produced by each panel while the tension Final is the one corresponding to a single panel. By means of the combination of serial / parallel connections, you can get the voltage or current required by the specific application.

The photovoltaic field of the plant object of the This invention is sized and calculated according to the mode of operate, of the energy needs of the application, and of the specifications imposed by the generator electrolyzer hydrogen in terms of voltage and working current.

To meet the needs of the electrolyzer, the serial / parallel field connection is optimized photovoltaic although if necessary, you can use a DC / DC converter also between the photovoltaic field and the electrolyzer

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A inverter that allows the transformation of the energy produced by the photovoltaic field or the fuel cell, in both cases in the form of direct current (DC) in alternating current (AC) to feed the needs of the specific application, as well as the compressor motors, pumps and the computer system of monitoring and control The power of the inverter is dimensioned in  function of the energy demands of the specific application. To the investor will be incorporated a PFC (Factor Corrector Power) to reduce reactive power consumption consumed by pumps and motors. With this improvement in consumption, we ensure an increase in component performance previous.

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He hydrogen generation system is formed by a electrolyzer (EL) and a compressor (CP).

In the electrolyser (EL) energy is used electric to carry out water electrolysis in such a way that hydrogen is obtained at the cathode and oxygen at the anode. He Electrolyzer can be alkaline or membrane type of proton exchange (PEM type). For this application they have discarded high temperature electrolysers for reasons of safety and for the easiest operation of the electrolysers operating at low temperature. Water fountain to carry out electrolysis comes from a tank of storage (H2O). If an electrolyzer is used alkaline, the electrolyte can be a hydroxide solution sodium NaOH) or potassium hydroxide (KOH) that can be stored in the storage tank (H2O) or within the own electrolyzer, in which case in the storage tank (H2O) pure water or tap water will be stored. In the case of using a PEM type electrolyzer, deionized water will be used which is stored in the storage tank (H2O). Water The electrolyser is delivered by a pump (B-1).

The electrolyzer (EL) can work with the electric power supplied directly from the solar panels photovoltaic (MF) or by means of the electrical energy coming from the commercial network. If it is fed from solar panels it is it is necessary that these have the appropriate serial / parallel configuration to provide the DC voltage that the electrolyser needs, or use a DC / DC converter to match the output voltage of photovoltaic solar panels (MF) with working voltage of the electrolyzer (EL). In the event that the electrolyser (EL) be powered by electric power from the commercial network will be It is necessary to use a current rectifier.

The output of the photovoltaic panels is Connects to the input of a photoelectric switch. This switch connects to another input that is coupled to the current rectifier which in turn is connected to the network of commercial distribution This switch allows the electrolyzer works from the energy supplied by the photovoltaic panels (MF) or from the commercial network, in case if available, when there is no sun. The direct current that out of the photoelectric switch is fed to the electrolyser to carry out the electrolysis of water. The position of switch depends on the energy that comes from the panels photovoltaic (MF). If the electrical energy that comes from the photovoltaic panels (MF) is enough for the electrolyzer (EL), the switch is in position "Off" while the electric power that comes from Photovoltaic panels (MF) is not enough for the correct Electrolyzer (MF) operation photoelectric switch goes to the "On" position, running the electrolyser with the energy provided by the network, in case there is connection to said network.

When the voltage is fed to Electrolyser (EL) is adequate, electrolysis of the water and hydrogen is obtained at the cathode and oxygen at the anode. He Oxygen can be used or not. In the first case it is stored at pressure in suitable containers, in the second case it is poured into outside, while hydrogen passes into a system of purification (SP) and a compressor (CP-H) for your subsequent storage in pressure tanks.

In the purification system (SP) the hydrogen water and this passes to the compressor (CP-H).

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He compressor (CP-H) is put into operation when the hydrogen pressure at the outlet of the purification system (SP) reaches the appropriate value and compresses the gas to the pressure at that pressure tanks are loaded. To control the compressor operation a pressure sensor is used (S-1) and a mass flow controller (CF-1). The mass flow controller (CF-l) will allow to evaluate the performance of the electrolyzer (EL).

In the event that the electrolyzer (EL) operates at a high enough pressure to load directly the tanks of the metal hydrides (HYDRAUR) are not will use the compressor (CP-H). In this case the hydrogen generated in the electrolyzer passes to the system of purification (SP) and from this to storage tanks.

As a hydrogen storage system, For this specific example, a set of tanks has been chosen  of metal hydrides (hydrides). For this type of application, it has opted for a type of metal hydride that allows hydrogen storage at low recharge pressure up to 10 Pubs. Although any type of metal hydride can be used that needs a higher recharge pressure, the fact of working with hydrides that can be recharged at low pressure allows in some cases the direct storage of hydrogen produced by the electrolyzer (depending on the pressure reached by the electrolyzer), without the need for a compression stage, at the same time which guarantees the safety in the operation of the plant.

The hydrogen stored in the tanks of Metallic hydrides (HYDRIDES) can be consumed in a stack of fuel (FUEL BATTERY) when solar panels Photovoltaic (MF) do not generate the required energy.

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He hydrogen enters the hydride storage tanks Metallic (HYDROID) coming from the compressor through the valve (EV-1) and leaves the tanks storage to the fuel cell through the valve (EV-4). The storage capacity of Metallic hydride tanks (HYDRIDES) are measured by the pressure sensor (S-1). In hours of sunlight, yes the pressure of metal hydride tanks is less than one default value the electrolyser (EL) and the compressor (CP-H) and the valve opens (EV-1) with which the hydride tanks are loaded Metallic (HYDROIDES). When metal hydride tanks (HYDRIDES) have reached the maximum load pressure, or when starts the fuel cell (FUEL BATTERY) close the valve (EV-1) the compressor stops (CP-H) and the electrolyzer (EL) and the valve (EV-4) that allows hydrogen to escape from the metal hydride tanks (HYDRATIONS) to the battery fuel (FUEL BATTERY).

The fuel cell (FUEL BATTERY) produces electrical energy from stored chemical energy in a fuel such as H2. For this two are carried out electrochemical semi-reactions. The H2 is fed into the anode fuel, where it oxidizes producing electrons and H +. The H + pass to the cathode through an electrolyte (typically polymeric membrane) where they combine with the O 2- ions resulting from oxygen reduction (typically the content in the air) to form H2O. The electrons that are generated in the anode is circulated towards the cathode through a circuit exterior, in which a load is placed, to close the system.

The type of fuel cell used in this invention is a low temperature fuel cell, being able to be of the type PEMFC, AFC, PAFC and other, provided that you use H_ {2} As fuel.

The hydrogen that is added to the pile of fuel, comes from the one stored in the metal hydrides (HYDRATIONS) or in case of failure or periods prolonged with absence of sun from which it is stored in form of compressed gas in the reserve system (HYDROGEN). He hydrogen flow that is fed to the fuel cell, is function of the power demanded and controlled with the controller mass (F-1) in the same way, the pressure of H2 that is fed to the battery is controlled by an electrovalve proportional (P-2) and a pressure sensor (S-2). The system is calculated and sized so that the necessary hydrogen is fed at all times, depending on the power demanded by the fuel cell. If necessary, it can purge hydrogen by opening the solenoid valve (EV-7).

The oxygen needed to complete the reaction electrochemistry that occurs in the fuel cell (PILA FUEL) is contributed to it in the form of air. The air is generated in a compressor (CP-A), passes through a filter (F) and the fuel cell is fed through a tube and solenoid valve (EV-8). The amount of air to be fed to the fuel cell (FUEL BATTERY) It is variable and depends on the power demanded of it. The air flow is controlled with the mass controller (F-2) and the pressure at which the air is fed, is controls with the working regime of the compressor (CP-A).

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The optimum working temperature of the battery fuel, in our case, being fuel cells of low temperature, it is around 60ºC. To get bliss operating temperature, a circuit of cooling consisting of a water tank (DS), a pump drive (B-2), a heat exchanger (I-1), and two temperature sensors (at the entrance and at the exit of the battery). Water is driven from the tank (DS) through the cooling circuit, through the pump (B-2), then going to the heat exchanger (I-1) in which its temperature is adapted to the Optimum input to the fuel cell (FUEL BATTERY). Then it enters the fuel cell in which it dissipates the thermal power required depending on the electrical power demanded and returns to the deposit (DS).

The plant has a security system to stop its operation in the event that there are hydrogen leaks. After stopping the system, all conduits through which hydrogen circulates, as well as the stack of Fuel (FUEL BATTERY) is filled with nitrogen.

In case of hydrogen leaks, the control system closes the solenoid valves (EV-1) or (EV-4) corresponding to the hydrogen stored in metal hydrides or in the system of security storage, depending on where you are feeding H_ {2} to the fuel cell, and open the solenoid valve (EV-2) corresponding to the line of nitrogen (NITROGEN).

Similarly, the electrolyzer (EL) stops at If you are producing hydrogen and the hydrogen compressor (CP-H) would stop working, in case It was working.

The plant has a detection system for H_ {2} for the identification of leaks.

Once the plant components have been described, its operation can be explained by following the flow patterns of Figures 3 and 4.

Figure 4 shows the mode of operation of the plant from the point of view of needs energy sources, while in the scheme of Figure 3 represents its mode of operation from the point of view of the Obtaining hydrogen.

From the point of view of energy demand of the system, the plant works as follows:

In case you have access to a network commercial the plant object of the patent would work as support and / or  replacement of the commercial network when a failure occurs in this one, while when the commercial network works correctly the energy supplied by the photovoltaic panels during the hours of sunlight or by the fuel cell, you can enter the commercial network once it has become current Alternate using the DC / AC inverter. Through this work mode, if there is a commercial network available, the energy will be used electricity from the commercial network for the consumption of needs of the application in question and to generate hydrogen through the electrolyser in the event that the tanks of hydrides are not full. To generate hydrogen in this case it will be necessary to transform the supplied AC electric current through the commercial network in DC and adapt it to the characteristics of the electrolyser by means of the current rectifier.

In case you do not have access to a network commercial or in case you want to generate energy in a way independent of a commercial network, the energy needs of the application will be covered from the photovoltaic panels or from the fuel cell, and only when there is a failure in the photovoltaic panels and in the fuel cell would make use of the commercial network if available. To operate in this way is it is necessary to check if the energy generated by the panels photovoltaic is enough to meet the demand of the application, or if it is not. In hours of sunlight in which the energy generated by photovoltaic panels (MF) is sufficient to meet the needs of the application, the DC power is will use for consumption following the previous stage of conversion in AC through the DC / AC inverter and to generate hydrogen in the Electrolyser (EL) in the event that hydride tanks (HYDRIDES) are not full following the diagram shown in Figure 3.

Finally when a network is not available commercial and not enough sunlight to generate power by means of photovoltaic panels (MF) energy needs they would be covered by the fuel cell. The pile of fuel generates DC electricity from the reaction between a fuel, which in the case of the present application is hydrogen and an oxidant that in this case is the oxygen in the air. So that the battery function properly and generate the desired energy must feed with the necessary hydrogen and air flow rates to the adequate pressure Therefore so that the fuel cell is put into operation, first check if the pressure of hydrogen in the storage system either tanks hydrides, or pressure bullets, is correct. If the pressure of hydrogen is not adequate the production system is checked and  hydrogen storage while if the pressure of hydrogen is correct the flow rate and pressure of the air coming from the air compressor (CP-A); feeding the compressor with an intermediate starting system (supercapacitors, etc). The air flow is determined from of the power demanded from the fuel cell (PILA FUEL) from the application and is regulated by the mass flow controller (F-2) while the Air pressure is regulated from the speed of the compressor (CP-A) using a PID controller designed to This application. The DC electric current generated by the battery fuel is sent to the DC / AC inverter where it is converted into AC electric current that is used in the application that try.

Due to the reaction that occurs within the fuel cell and the Joule effect, the fuel cell It tends to get hot when it's working. To avoid a excessive heating and to achieve maximum performance of the fuel cell it is necessary to control the temperature of operation of the same, through a cooling system.

Refrigeration of the fuel cell (PILA  FUEL) is carried out by means of a circuit that uses water and consisting of a water storage tank (DS), a pump of recirculation (B-2) and a heat exchanger (I-1).

The temperature control of the battery fuel is made by regulating the flow of water to through the pump (B-2) depending on the operating temperature of the fuel cell (PILA FUEL).

Hydrogen production can be followed through the scheme presented in Figure 3.

Hydrogen is obtained from the Water electrolysis in the electrolyser (EL). The needs of  hydrogen production are determined from the pressure of the hydride tanks (HYDRAUR) that is measured by the sensor pressure of energy availability to power the electrolyzer (EL) and fuel cell operation (FUEL BATTERY). When the storage pressure of the hydride tanks (HYDRAUR) is less than the maximum established and the fuel cell is not working it would be necessary to produce hydrogen in the electrolyzer (EL). If the fuel cell is running to provide power to the application considered, then hydrogen is being consumed from the tanks of hydrides (hydrides) and hydrogen will not be produced in the electrolyzer (EL). The possibility of producing is not contemplated hydrogen at the same time it is consumed, since the main application of the plant is to produce hydrogen from solar energy photovoltaic in hours of sunlight and consume it in the stack of fuel when there is no solar energy available.

To control the loading of the hydride storage tanks (HYDRAUR) with the hydrogen generated in electrolyzer (EL) and its discharge to provide hydrogen to the fuel cell, in addition to the pressure sensor there are two valves (EV-1) and (EV-4). When the hydride tanks (HYDRID) are being charged with the hydrogen generated in the electrolyser (EL) the valve (EV-1) would remain open and the valve (EV-4) would remain closed, while when the hydride tanks (HYDRID) ) are being discharged to provide hydrogen to the fuel cell (FUEL BATTERY) the valve (EV-1) would remain closed and the valve would open
(EV-4).

Once the relative checks have been made to the needs of hydrogen production, if the tanks of hydrides (hydrides) are not full and the fuel cell is not The type of energy available is checked. Yes there are available solar energy will be used to produce hydrogen, while when there is no sunlight the hydrogen will be obtained using energy from a commercial network if there is availability of it. In case there is solar energy available, the electrolyzer (EL) will be put into operation when the DC voltage generated by the photovoltaic panels (MF) is appropriate, while if the energy is used of a commercial network the AC electric current will be transformed into DC and the electrolyzer voltage (EL) will be adapted by rectifier.

Depending on the characteristics of the panels  Photovoltaic (MF) and electrolyzer (EL) may be it is necessary to use a DC / DC converter to transform the voltage DC generated through photovoltaic panels (MF) in the DC voltage required for electrolyzer operation (HE).

The electrolyser (EL) works by producing hydrogen from the electrolysis of water as long as the maximum storage pressure of the hydride tanks (HYDRAUR) is not reached. The hydrogen storage pressure in the hydride tanks (HYDRATIONS) is recorded continuously by the pressure sensor (S-1). If the pressure at which the hydrogen is produced inside the electrolyzer (EL) is sufficient to recharge the hydride tanks (HYDRAUR) it would not be necessary to use a hydrogen compression system and the recharge of the hydride tanks would be carried out directly . If the working pressure of the electrolyser (EL) is not sufficient to recharge the hydride tanks (HYDRAUR), a compressor would be needed to compress the hydrogen that exits the electrolyzer (HYDRAUR) to the refill pressure of the hydride tanks (HYDRAUR) . In the latter case, the hydrogen compressor (CP-H) would be put into operation when the pressure of the electrolyzer (EL) is necessary for its correct operation. To regulate this form of operation, the pressure at which the electrolyzer (EL) supplies the hydrogen is continuously recorded by the pressure sensor integrated in the electrolyzer itself. When the pressure of the electrolyzer (EL) is adequate, the valve (EV-1) would be opened and the compressor (CP-H) would be put into operation. Finally, when the hydride tanks (HYDRID) are full, which is detected by the pressure sensor (S-1), the compressor (CP-H) and the electrolyzer (EL) would stop and the valve would close
(EV-1).

In order for the plant to operate in accordance with the specifications that have been previously mentioned,
A plant monitoring and control system that allows the monitoring of the values of all the variables that define the behavior of the plant and its control is developed. The monitoring and control of the plant can be carried out in situ or remotely by means of a computer program that has been developed specifically for the patent application.

The program consists of 3 main stages: one initialization stage; a monitoring and control stage that runs continuously while the plant is running, and a completion stage. In the stage of initialization the working conditions are indicated from the point from the point of view of obtaining hydrogen and from the point of view of the generation of energy for the application in question. In addition, at this stage all ports are opened and checked at that the different instruments are connected, they are initialized variables and the data transmission system is initialized to Remote plant monitoring. In the stage of completion all control ports of the Different instruments and remote data transmission. Finally, in the monitoring and control stage they are executed all the necessary sequences for the correct functioning of the plant in the manner described above. From this program stage controls all necessary instrumentation for the monitoring and control of the plant, which consists fundamentally of the following components:

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A data acquisition and control system with several modules analog input and output whose channels connect the measuring devices and actuators respectively.

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A set of temperature sensors, pressure controllers mass flow, solar radiation and hydrogen sensors that allow to monitor the behavior of the plant.

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A set of actuators such as valves and pumps, which allow control the operation of the plant from the point of view of obtaining hydrogen and the energy needs of the application.

Claims (10)

1. System for the production of hydrogen and electrical energy from photovoltaic energy, where photovoltaic energy is obtained with at least one module of photovoltaic cells (1) from solar radiation; characterized in that said module (1) feeds an electrolyser (3) that generates hydrogen from water electrolysis and that has storage means for the hydrogen produced in storage systems; including at least one fuel cell (2) that allows the generation of electric energy from the stored hydrogen; so that the improvement in the production performance of electric energy from photovoltaic energy and its availability is facilitated, when hydrogen is used as an energy storage intermediate vector. 2. System for producing hydrogen and electrical energy from photovoltaic energy, according to claim 1, characterized in that said photovoltaic cell module (1) has a solar tracking device. 3. Hydrogen and electrical energy production system from photovoltaic energy, according to claim 1, characterized in that the fuel cells (2) are low temperature (PEMFC, PAFC, AFC). 4. System for the production of hydrogen and electrical energy from photovoltaic energy, according to claim 1, characterized in that the H 2 storage system is sized for an autonomy of at least three days. 5. System for the production of hydrogen and electrical energy from photovoltaic energy, according to claim 1, characterized in that the system has an additional reserve of hydrogen stored in the form of pressurized gas. 6. System for the production of hydrogen and electrical energy from photovoltaic energy, according to claim 1, characterized in that it is made with components of easy portability. 7. System for the production of hydrogen and electrical energy from photovoltaic energy, according to claim 1, characterized in that it has a control subsystem for monitoring and remote control via an Internet connection or through a local network. 8. System for the production of hydrogen and electrical energy from photovoltaic energy, according to claim 7, characterized in that said subsystem includes sending alarms about the state of the system and / or failures thereof, by means of GSM text messages or the like . 9. System for the production of hydrogen and electrical energy from photovoltaic energy, according to claim 1, characterized in that it is structured in an energy production plant whose functional blocks consist of the photovoltaic cell module (1) connecting with a DC / AC inverter (4) for conventional energy production or with the electrolyzer (3), generating hydrogen that will be stored and consumed in the fuel cell (2), generating electric power; feeding this inverter (4) to water pumps (6) and air compressors (7) of the plant, while solenoid valves (8) and flow meters (9) of the same are fed by the photovoltaic module itself (1) to through DC / DC converters (5); the corresponding electrolyzer (3) being fed, through other DC / DC converters (5), by means of the photovoltaic module (1) or by means of a rectifier (11) that connects with the conventional electricity grid (12) and with the referred module ( 1) through a photoelectric switch (10). 10. System for the production of hydrogen and electrical energy from photovoltaic energy, according to claim 1, characterized in that the hydrogen is produced by electrolysis of water, in a low temperature electrolyser, of the alkaline type or PEM type.