AU2020291632A1

AU2020291632A1 - Hybrid solar high-efficiency thermodynamic device and hydrogen-oxygen pair producing a plurality of energies

Info

Publication number: AU2020291632A1
Application number: AU2020291632A
Authority: AU
Inventors: Sylvain Pare
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-06-13
Filing date: 2020-05-26
Publication date: 2022-01-20
Also published as: IL288881A; WO2020249884A1; EP3983729A1; CA3142977A1; KR20220024541A; FR3097305A1; FR3097305B1; JP2022537691A; CN114127485A

Abstract

The invention relates to a power generation system comprising a solar energy collection means and electricity generation means, characterized in that the electricity generator comprises an absorber (5) receiving solar energy for heating a thermodynamic device, said absorber (5) being arranged in an optional heating zone by a burner (8).

Description

HYBRID SOLAR HIGH-EFFICIENCY THERMODYNAMIC DEVICE AND HYDROGEN-OXYGEN PAIR PRODUCING A PLURALITY OF ENERGIES

Field of the invention

The present invention relates to the field of solar energy production from a system of concentrators ensuring the heating of a heat transfer fluid to high temperatures, up to 5000 or even more than 7000 C, in a thermal collection element with an absorber placed at the focus of the concentrator or the series of concentrators.

In general, the purpose of a solar energy conversion device is to provide useful power by transforming the energy of the collected solar radiation. For this purpose, it comprises an absorber, that is to say, a physical element whose function is to convert the incident solar electromagnetic energy into another form of useful usable energy (for example, electrical energy in the case of a photovoltaic module or a thermoelectric module, thermal energy in the case of a solar water heater, etc.). However, the useful power delivered by the device depends on several factors, including the conversion efficiency of the absorber, the surface area of the absorber allocated to collecting solar radiation (or "collector area") and the power of the incident solar radiation on the absorber. Since the efficiency of the conversion depends on the technology used to produce the absorber, for a given technology, the useful power is therefore regulated by the surface allocated to the collection and the power of the radiation.

In particular, when the surface allocated to collecting solar radiation is small, for example to limit the cost of the absorber, it is typical to concentrate the power of the solar radiation on the absorber by means of a solar concentrator (for example a Cassegrain system, a parabolic mirror, a standard or linear Fresnel lens, a set of lenses, etc.). The solar concentrator is an optical system that focuses solar radiation on a focal plane, and the collector area of the absorber, which is planar, coincides with the focal plane of the concentrator. Focusing the radiation on the collector area of the absorber thus makes it possible to compensate for the small size thereof.

However, a solar energy conversion device based on a solar concentrator is sensitive to the angle of incidence of the solar radiation, and especially as the collector area of the absorber is reduced. In fact, there is always an angle of incidence of solar radiation, defined with respect to the optical axis of the solar concentrator, beyond which focusing is no longer carried out on the absorber itself.

In addition, the incidence of the sun varies throughout the day, which is why concentrating solar conversion systems are motorized (e.g. using a tracker) to track the progression of the sun in the sky, in order to ensure a normal incidence of solar radiation. However, this type of system requires very precise tracking of the sun, a slight angular shift (e.g. 0.10) with respect to the sun directly resulting in a significant drop in the performance of the device.

Prior Art

International patent application W02013142911 is known in the state of the art, describing a hybrid receiver-combustor for capturing heat energy from a solar source and from a fuel source, the hybrid receiver-combustor comprising: a chamber operable as a combustion zone for production of heat energy through a combustion process using the fuel source; the chamber having an aperture through which concentrated solar is receivable; and a fluidic seal system associated with the aperture, the fluidic seal system being operable to establish a fluidic seal for restricting fluid flow through the aperture during the combustion process.

Patent US 5,884,481 is also known, describing a heat engine heater assembly for transferring heat to working fluid within said heater assembly from solar energy and combustion gases produced by burning a fuel, said heater assembly comprising: • a housing, forming a chamber, • a plurality of heater tubes within said chamber, for containing the working fluid, wherein said heater tubes are positioned about a central axis and said heater tubes form a substantially opaque surface for incident solar radiation, • said housing having an aperture allowing said heater tubes to be inserted, • a fuel combustor, for mixing and burning air and fuel to produce combustion gases in said housing, • air supply means for supplying air to said fuel combustor, • fuel supply means for supplying fuel to said fuel combustor,

• combustion gas circulation means for circulating said combustion gases past said heater tubes, and sealing means for inhibiting said combustion gases from escaping said housing through said aperture.

Drawbacks of the Prior Art

The drawback of the solutions of the prior art is that in the absence of sun or cloud cover, the level of energy production decreases considerably and no longer makes it possible to provide the expected energy. These installations therefore require association with other installations or access to an independent electricity network to overcome the random production interruptions inherent to solar power plants.

Moreover, in the solution described in patent application W02006027438, significant losses occur in the primary and secondary working fluid circuits.

Solution provided by the invention

In order to remedy these drawbacks, the present invention relates to a system for generating power by a solar energy collection means and an electricity generation means, characterized in that the electricity generator comprises an absorber receiving solar energy for heating an expansion gas, said absorber being arranged in an optional heating zone by a burner.

Advantageously, the system according to the invention has all or some of the following features: - it further comprises hydrolysis means. - the electricity generation means are designed to receive thermal energy resulting from the recombination of the hydrolysis products in the absence of solar energy. - the gas in the thermodynamic device is placed at the focus of a concentrator. - it further comprises means for supplying the electrical production means with an additional energy source in a reversible manner.

Description of the Invention

Thermodynamic device of the free piston type, all operating either with concentrated solar energy or with solar fuel (without sun), or even biogas or any other conventional heat source. Hot source THT and cold -253°. Variable speed HP and THT/TBT th module. Cloudy passage detection = preheating. Electricity production by a linear alternator

NREs (New Renewable Energies) have become essential, but solar energy is undoubtedly the source of NRE (New Renewable Energy) most in line with global energy needs and in response to climate challenges. The present invention relates to the field of transforming solar energy into electricity with efficiencies of up to 60%, i.e. times more than conventional PV (Photovoltaic) technology.

Current NRE solutions such as PV or CSP (Concentrating Solar Power Plant) do not adequately meet current and future energy needs due to their very low "real" efficiencies of barely 6 to 20%, their high price, their implementation using complex and expensive means requiring specialists, the pollution they generate during their manufacture, the need to make abundant use of limited land resources, the impossibility of recycling their components, their mono-production of electricity only. Known thermodynamic devices require heavy maintenance and have a limited service life

Furthermore, these methods require storage means based on molten salt or expensive and polluting electrochemical batteries, which have particularly limited capacities and reduced and decreasing service lives.

The present invention overcomes these problems by offering an extremely intelligent, efficient, durable and environmentally friendly solution for transforming solar energy owing to an extremely simple, efficient and particularly innovative method with a very low cost and a very high efficiency, in which the storage is done by means of solar fuel in a closed circuit with a service life of up to 40 years. In addition, the device can easily be produced with a carbon footprint close to zero.

Detailed description of the invention

A thermally insulated vacuum chamber closed by a window transparent to solar radiation receives solar energy concentrated on an absorber, which will convert the solar energy into high temperature thermal energy that can be 12000 C to transfer it into the working fluid within the thermodynamic device, the fluid being hydrogen.

The vacuum chamber can be insulated either by a set of vacuum walls (Dewar type) or by suitable high temperature insulation. The heat losses are used to produce heat for various applications related to the device (cryogenic production) or for external applications (cooking, sterilization, hot air, etc.).

Apart from solar irradiance, the thermodynamic process is supplied with heat via a burner receiving solar fuel (h2/o2), which produces a powerful exothermic reaction that is transmitted to the absorber. The solar fuel is ideally in liquid cryogenic form, becoming gaseous after passing through an exchanger, for reasons of volumetric storage density, and its very low temperature allows the efficiency of the thermodynamic device to be increased correlatively. The burner accepts any other suitable gas mixture (biogas, methane, oil, etc.), and the absorber accepts any suitable heat source.

The solar fuel combustion residue is water vapor, which can be recycled indefinitely in a closed circuit method. The heat produced by the water vapor can ideally be recovered via an exchanger, as can all the heat losses of the invention that make it possible to supply a certain number of thermal processes such as cooking, sterilization, drinking water production by distillation, or even supplying a thermodynamic device allowing cold production in a whole range of temperatures, including cryogenic, the immediate application of which is the liquefaction of solar fuel.

The advantage of liquefaction is to obtain a storage volume at least double that of compression methods such as in tanks at 700 bars, the density then being 42 kg of h2/m3 and 71 kg of h2/m3 in cryogenic form. The other advantage is that storage in liquefied form avoids the risk of explosion associated with pressurized tanks.

This liquefaction being carried out with the heat losses from the vacuum chamber/absorber via a module, for example of the Stirling type, there is therefore no additional cost, which makes it possible to liquefy the solar fuel almost free of charge.

The solar fuel being composed of h2 and o2, the device can be continuously recharged with h2 working gas from the thermodynamic device to compensate for the losses caused in particular by the gas diffusion phenomenon. These losses usually prevent the use of h2 and require the use of a non-renewable rare and expensive gas, such as helium, the performance of which is lower.

This solar fuel can be partly produced in the enclosure owing to the concentrated solar radiation causing a high temperature on the absorber on which a thin stream of water is sent, which breaks down into h2 and o2 under the effect of the intense heat. A device is then added to allow the separation of the two gaseous compounds.

Furthermore, any thermodynamic device operates with a hot source and a cold source, the terminal efficiency being a function of the temperature difference; the higher this differential, the greater the final efficiency. The best-known thermodynamic machines, of the Stirling type, make it possible to obtain efficiencies of the order of 40% with a hot temperature of 800 0C and a cold temperature linked to the ambient temperature, that is to say, approximately 250 C.

The invention makes it possible to obtain much higher working temperatures, with a hot temperature of about 1200 0C and a cold temperature which is that of liquid hydrogen, i.e. minus 253 0C, thus making it possible to reach efficiencies greater than %.

The hot temperature is obtained from the absorber that receives the heat from the concentrated solar flux or from the flame from the solar fuel, which reaches 28000 C at the hottest point, or from another heat source (biogas, methane, oil, etc.). The choice of an absorber made of suitable materials makes it possible to work in a temperature class of 12000 C, in particular with certain materials or ceramics. This absorber transmits this high temperature to the working fluid, which is hydrogen due to its particular properties. The absorber is designed to receive both concentrated solar radiation and a flame or to produce solar fuel at high temperature by thermolysis of water on the absorber.

The thermodynamic device consists of a method with free pistons being coaxial in a cylinder, the whole being in a closed cavity filled with h2 at high pressure, for example 150 or 200 bars, the h2 being the working fluid. The first piston, called the displacer, is located in the immediate vicinity of the absorber. When the gas heats up, its volume increases and moves the displacer piston, this volumetric change acting on the second so-called working piston, which will move in proportion to the first.

As the working gas makes a loop between the two pistons from the outside of the coaxial cylinder, a rapid imbalance is created that displaces the working gas in an exchanger that is ideally cooled by the liquid h2 circuit or any coolant at low temperature, the sudden volume change causing a strong imbalance that returns the displacer piston to its original position, and the cycle begins again. In the external circuit between the two pistons there is a device called regenerator, the thermal inertia of which makes it possible to carry out a heat transfer such that it contributes to the energy improvement of the overall efficiency.

Under ideal conditions of pressure, temperature, stroke, frequency and other physical parameters, the phenomenon is self-sustaining. As soon as one of the parameters varies, the power available to the working piston varies, the latter driving a linear alternator; the output power varies in proportion to the amplitude of the stroke.

The best rate of energy production, or efficiency, occurs when the device resonates, implying that the assembly is "tuned," and therefore all the parameters are perfectly optimized and controlled. Since the power of the assembly varies with the thermal power received, the latter varies in particular based on the solar irradiance. The known machines are equipped with mechanical springs and are adjusted so as to generate a resonance at a predetermined frequency, which is fixed to produce an alternating current of a certain frequency that is suitable for electrical networks, such as 50 or Hz. As a result, the efficiency is limited due to the fact that the operating parameters such as the resonance cannot be adjusted, in particular involving an adjustment of the stroke of the pistons.

Unlike known machines, the device according to the invention makes it possible to maintain this resonance by continuously acting on the stroke of the pistons. To do this, the alternator's control electronics generate a counter-electromotive force, called CEMF, which makes it possible to vary the power of the alternator and therefore to act on the stroke of the pistons while producing a spring effect maintaining the resonance. This CEMF can be located on both pistons if necessary to obtain a very fine regulation and therefore the best efficiency, each piston then being equipped with a stator, i.e. the static part of the electromagnetic circuit, and a linear "rotor," or moving part of the electromagnetic circuit.

To prevent wear and ensure a long service life for the device, the pistons move and are centered by an "air cushion," which is h2, called an h2 cushion. This h2 cushion is generated by grooves located on the periphery of the pistons, these generating micro vortices within the cavities thus created, which result in local overpressures and thus prevent the pistons from touching the walls of the cylinder and therefore avoid any friction, thus causing no wear and thus making it possible to produce a hermetic unit like refrigeration compressors, with a service life of the order of 40 years.

Aim of the invention

The present invention relates to a system for generating power comprising a solar energy collection means and an electricity generation means, characterized in that the electricity generator comprises an absorber receiving solar energy for heating a thermodynamic device, said absorber being arranged in an optional heating zone by a burner.

Advantageously, the system comprises a vacuum chamber having internal/external thermal insulation and an anti-reflective window.

It also relates to the use of a cryogenic cold h2 at approximately minus 253 degrees and a heat source at approximately 12000 C with an efficiency of 60%

According to a variant, it uses pistons with variable stroke under resonance by counter electromotive force and electronic regulation.

It provides for poly-energy production (electricity, cold, heat, solar fuel (trade name), drinking water, UHT sterilization, steam, etc.) unlike mono-energy power sources (PV, CSP, etc.)

To reduce the wear of the pistons/cylinders, an air/or hydrogen cushion is used.

The recovery of heat losses operates a cryogenic cold generator and activates a vacuum pump.

The system according to a variant further comprises hydrolysis means for generating a hydrogen-oxygen pair ("solar fuel" trade name) by solar h2o concentration on a hot surface

Compensation for h2 losses is ensured by gas diffusion by sampling a fraction of solar fuel (trade name) and re-injection into the thermodynamic module

Detailed description of a non-limiting example of the invention

The present invention will be better understood on reading the detailed description of a non-limiting example of the invention which follows, with reference to the appended drawings, where: - Fig. 1 shows a schematic view of a first embodiment of the invention - Fig. 2 shows a schematic view of a second embodiment.

Schematic description of the invention

Fig. 1 shows a schematic view of a first embodiment

The installation for example comprises a solar concentration system illustrated schematically in the described example by a flat collector (1) forming a diffraction grating of the Fresnel sensor type returning the solar radiation to a hemispherical concentrator (2) mounted on ,an adjustable structure to concentrate the radiation at a point located at capture equipment formed by a vacuum chamber (3) opening through a window transparent to concentrated solar radiation (4).

The vacuum chamber (3) defines an absorbent cavity limiting losses by diffusion in the air. The window (4) is covered with an anti-reflection coating in the appropriate spectrum to avoid more than 30% optical/heat losses. General thermal insulation can be obtained, for example, with aerogels, expanded perlite, or even certain forms of carbon/graphite with excellent insulating properties and at low cost, since these are abundant and recycled materials. It can also be a set of vacuum-type Dewar chambers.

The chamber (3) contains an absorber (5) made of a suitable material, such as ceramic. The surface of the absorber (5) has microcavities produced during molding, to approximate the characteristics of a black body.

The chamber (3) has several interfaces with pipes (6 to 9): - A pipe (6) for the outlet of hot air adjustable in temperature for heating, cooking and all metallurgy or industrial chemistry operations. This pipe (6) allows the controlled transfer to additional equipment for the use of hot air, and also makes it possible to reduce the pressure inside the chamber (3) and to discharge the combustion products. - a pipe (7) for injecting a water mist that will be subjected to a temperature that can reach 2,5000 C, causing its spontaneous chemical separation into its two elements, H2 and 0, by cracking or thermolysis of the water allowing hydrogen and oxygen to be obtained, by using heat to dissociate the atoms making up the water molecule H20. This thermochemical reaction begins at high temperature (between 850 0C and 900 0C) and becomes complete around 2,5000 C. - a pipe (7) for extracting a jet of molecules of different masses, which are then separated by means of an appropriate device to obtain two distinct streams of hydrogen and oxygen. - a pipe (8) for supplying a previously stored HHO burner. This burner allows energy to be supplied to generate a flame at around 2,800C, allowing the system to operate at night or in an overcast sky.

The absorber device is modular, thus allowing the use of external heat when, for example, the HHO tank is empty, or of other fuels such as biogas or any other source.

A cloud detection and pre-heating system (10) completes the installation.

Description of a second embodiment

Fig. 2 shows a schematic view of a second embodiment.

As in the previous example, it comprises a controlled atmosphere chamber (3) opening through a window transparent to solar radiation (4) and containing an absorber (5). This absorber (5) produces a high temperature for the thermolysis of water introduced into the chamber (3) by misting. It is also thermally coupled to an energy transformer (10). This energy transformer (10) consists of a thermodynamic device of the FPSE or other type, in cogeneration associated with a Stirling liquefaction (or other) device allowing the produced gases (H2/02,) to be liquefied with a view to their storage, then a Stirling (or other) refrigeration unit for producing cold working in cogeneration with the inevitable losses of the liquefier.

A storage tank for H2 and possibly liquefied 02 provides an energy carrier during nighttime or unfavorable weather conditions, with a view to reinjection via a burner. The separation of the gaseous components obtained by thermolysis is ensured by a cell separating the gases resulting from the thermolysis, and which can be either a supersonic vortex, an HT electrolysis, a proton membrane, etc. The absorber (5) is made, by way of example, for example of ceramic or any suitable material.

In the example illustrated by Fig. 2, the absorber (5) is thermally coupled to an electricity generator (10) constituted by a thermally insulated confinement chamber (11), inside which a coaxial high-pressure cylinder (12) is positioned. This high-pressure cylinder (12) is also thermally insulated.

Inside this high-pressure cylinder (12) moves a high-pressure piston (13) that ensures the cyclic compression of a gas actuating a second stage comprising a low-pressure piston (14).

Air or water exchangers (15, 16) surround the confinement chambers (11) and electrical coils (17).

The general composition in the form of nested cylinders allows the optimization of surfaces and volumes, while minimizing head losses. Furthermore, this type of arrangement allows easy manufacture as well as assembly. The seals between piston/cylinder segments can be achieved by grooves generating micro-vortices.

A possible additional stage of larger size could use with more conventional materials such as aluminum, PTFE, steels, cast iron, etc.

The device benefits from continuously adjustable feedback via the electric generator, which advantageously replaces the mechanical spring or the connecting rod with c.e.m.f (counter-electromotive force). Thus, by varying the electrical parameters, an adjustable stroke is available, making operation in continuous resonance mode possible.

In addition, the electromagnetic control of the pistons allows easier starting by acting on them and initiating the start-up process.

This type of motor is reversible to produce cold or heat. This configuration is possible by using the linear electric generator as a motor via the control electronics.

The invention has appropriate sensors and computers making it possible to detect a cloudy passage in advance and to anticipate the operation of the additional heat source (hhoor other) before the decrease in solar power.

Claims

1) System for generating power comprising a solar energy collection means and an electricity generation means, comprising an absorber (5) receiving solar energy for heating a thermodynamic device, said absorber (5) being arranged in an optional heating zone by a burner (8), characterized in that the surface of said absorber (5) has microcavities.

2) System for generating power comprising solar energy collection means and electricity generation means according to claim 1, characterized in that it comprises a vacuum chamber having internal/external thermal insulation and an anti reflective window.

3) System for generating power comprising solar energy collection means and electricity generation means according to claim 1, characterized in that said absorber (5) is thermally coupled to an electricity generator (10) formed by a thermally insulated confinement chamber (11), inside which a coaxial high-pressure cylinder (12) is positioned, a high-pressure piston (13) moving in said high-pressure cylinder (12) to ensure cyclic compression of a gas actuating a second stage comprising a low-pressure piston (14).

4) System for generating power comprising solar energy collection means and electricity generation means according to claim 1, characterized in that the chamber (3) surrounding said absorber (5) has several interfaces with pipes (6 to 9): - A pipe (6) for the outlet of hot air adjustable in temperature - a pipe for the injection of a water mist - a pipe for extracting a jet of molecules of different masses, which are then separated by means of an appropriate device to obtain two distinct streams of hydrogen and oxygen - a pipe for supplying a previously stored HHO burner.

Fig. 1

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Fig. 2 Fig. 2

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