FR2697579A1 - Method of energy extraction from heat source - is driven by high and low temperature thermo-chemical reactors. - Google Patents

Abstract

Mechanical energy is produced from the output of a heat source (10), by reheating a primary thermo-chemical reactor, suitable for the extraction from the gas, heat energy, by using the energy produced by the heat source (10). The gas freed by the thermo-chemical reactor has a fixed pressure and is used to feed the input of a turbine (3). The gas recovered from the second thermo-chemical reactor (2), of the same type as the primary, is used to extract the heat and generate a cold source (23), which enables the temperature of the secondary reactor (2) to be held at a lower point than that of the primary reactor (1). USE/ADVANTAGE - It enables mechanical energy to be produced from low grade heat.

Description

DESCRIPTION
The present invention relates to a method and a device for producing mechanical energy from a hot source.

 The technical sector of the invention is the field of the production of energy production equipment by heat exchange.

 One of the main applications of the invention is to rotate a gas expansion turbine allowing the driving in rotation of a shaft which can then be coupled to any system using this mechanical energy and this by using the recovery of thermal energy produced by any hot source.

 This application can be very interesting to produce electricity, for example on a boat by recovering the heat of the fumes released by the main propulsion engine to run an alternator thus saving the diesel engine driving a generator. .

 In fact, equipment is known which allows such production of mechanical energy by essentially expanding suitably heated steam, but to avoid condensation thereof in the turbine, said steam must first be heated to a temperature of about 400 for a inlet pressure of at least 20 bars in the turbine, so that during its expansion, according to the MOLLIER diagram, up to approximately a few bars for the best performance, it remains above its condensation temperature.

 For this, it is therefore necessary to overheat the steam and to have a heat source at a very high temperature, which on the one hand, is not the case of the fumes given off by an engine and which, on the other hand, in any case wastes a part of thermal energy, since the vapor therefore leaves the turbine at a still high temperature of the order of 200 C and more.

 In general, the heat thus released and which would otherwise be lost is recovered, to heat fluid circuits through exchangers, and use this fluid in heating systems, directly or after storage.

 The problem is therefore to be able to supply and produce mechanical energy from heat energy at medium temperature, which can be released and / or recovered by a heat transfer fluid, whatever its pressure which may be even atmospheric pressure.

A solution to the problem posed is a method of producing mechanical energy from a hot source, such as
- At least one first thermochemical reactor is heated, capable of releasing or adsorbing gas according to its temperature and its pressure, using the calories released by said hot source;
- the gas released by the heating of this reactor to a given pressure is recovered, and the inlet of a pressure reduction turbine is fed therefrom, from which it exits at lower pressure and at lower temperature after having driven this one in rotation;
- This expanded gas is then recovered in at least one second thermochemical reactor, of the same type as the first where it is adsorbed or chemically bound, by releasing heat which is removed using any cold source, which makes it possible to maintain this at least second thermochemical reactor at a temperature lower than that of at least the first thermochemical reactor.

 At the end of this first phase of releasing the gas from the first reactor and of adsorption of this gas by the second reactor, these two reactors are inverted by heating the second by the hot source so that it in turn releases said gas which it adsorbed in the previous phase, and by cooling the first by the cold source so that it in turn adsorbs the gas released by the other after expansion and drive of the turbine.

 In a preferred embodiment, the two at least reactors are connected by at least two circulation networks, one in heat transfer fluid and the other in reaction gas, the first network connecting and looping, on the one hand a circuit between the hot source and at least that of said reactors which releases the gas, and on the other hand a circuit between the cold source and at least that of said reactors which adsorbs the gas, and the second network connecting the two reactors to each other, through the turbine.

 To accelerate the inversion time of the two said reactors, even if this is to the detriment of the efficiency, the at least two gas inlets / outlets of the at least two reactors are directly connected by a circuit shorting the turbine and which is closed during the energy production phases by expansion of the gas released by at least one reactor, and said circuit is opened at the end of each mechanical energy production phase, when the cold reactor has adsorbed the gas released by the hot reactor and that it is then largely emptied of this gas.

 The result is a new method and devices as described below making it possible to carry out said method of producing mechanical energy from a hot source.

 In fact, there are known such thermochemical reactors containing a solid capable of fixing and releasing a gas according to their temperature and their pressure, while releasing and absorbing thermal energy respectively: these reactors are used to date essentially as pumps for heat and cold and / or heat production units, by using the internal pressure of these reactors and by circulating a refrigerant in a cold circuit and an external exchanger, when one wants to cool for example.

Mention may be made in this context of a certain number of patent applications filed by the company ELF on a certain type of thermochemical reactors and of installations allowing the use of these reactors, in which the reaction medium essentially comprises expanded graphite, in which is packed one or more salts in pulverulent form, and whose gas is preferably ammonia: we note among others, the patent application No.FR. 2,620,046 published on March 10, 1989 and relating to a "process for conducting an absorption and desorption reaction between a gas and a solid", the application FR. 2,642,509 published on 03
August 1990 on a "device for producing cold and / or heat by solid-gas reaction", or international patent application WO FR 88/09466 published on December 1, 1988 on a "device and method for producing cold and / or heat by solid gas reaction ".

 We could cite in this same field, other patents filed by this company, but also by others like that FR.

2,590,356 from the company JEUMONT SCHNEIDER published on May 22, 1987 on a "device for the continuous production of hot and cold" and also comprising at least two reactors containing a solid adsorbent of a refrigerant.

 None of these systems known to date in the field of thermochemical reactors has been used to produce mechanical energy as in the case of the present invention: this is therefore a new application of thermochemical reactors which can either fix a low pressure gas, or release this high pressure gas, depending on its temperature; this new application is such that at least two of said thermochemical reactors are connected, one heated by any hot source and the other cooled by any cold source, by a supply circuit for said gas comprising an expansion turbine, allowing to produce mechanical energy by its rotation.

 Said rotation thus produced then makes it possible to drive any mechanical system such as a pump, etc., but also and above all one or more alternators then making it possible to produce electricity.

 According to the operating mode of said thermochemical reactors as described below, it is sufficient that said hot source is at a temperature of the order of 200 "C and the cold source at ambient temperature, thanks to any exchange system with , either the ambient air, or a fluid such as for example sea water when it is an installation on board a ship, or soft when one is near a watercourse. thus a large part of the heat energy released, for example by the fumes of a diesel engine or by any other heat source for which a temperature of 200 is not recoverable in the systems known to date, and which is often wasted or only possibly recovered on heat exchangers to serve as heating.

 Thanks to the present invention, it is therefore possible, for example, to significantly increase the efficiency of diesel generator sets, of which in general 30% of the potential energy of the fuel allowing their operation is evacuated in the flue gases, while approximately 35% at most of this energy is only transformed into useful electricity: thanks to the process and the device of the present invention, the 30% of the energy released as heat in the fumes can then be recovered up to approximately 40% of their heat energy in mechanical and therefore electrical form, which then brings the total efficiency of the diesel engine of the generator set to more than around 45% instead of 35%.

 In other areas of use, by directly recovering the heat from the fumes given off by large engines such as propulsion on a boat, this makes it possible to drive alternators directly, without then requiring diesel groups to drive them. this.

 We could cite other advantages of the present invention, but those mentioned above already show enough to demonstrate its novelty and interest.

 The description and the figures below represent examples of embodiment of the invention, but are in no way limiting. Other embodiments are possible within the scope and scope of the present invention, in particular in using thermochemical reactors of different types, and using hot springs and cold springs of different origins.

 Figure 1 is a Clapeyron diagram showing the operation of the method according to the invention.

 Figure 2 is a block diagram of the power supply to the gas circuit driving the power generation turbine.

 FIG. 3 is a diagram of the principle of circulation of the heat-transfer fluid (s) between the cold and hot sources and the reactors.

Figure 1 is a representative diagram, in the diagram of
Clapeyron, on the one hand, of a curve 26 representing the line of equilibrium of state between the liquid and the vapor of the gas considered, such as for example ammonia, and on the other hand, a curve 27 corresponding to the equilibrium of the chemical reaction between a salt and said gas, constituting a thermochemical reaction according to the invention and such that [gas] + [salt] = [salt + gas] + Q.

 This reaction is reversible at any level of temperature T and pressure P of the gas, such as ammonia, and this reaction is accompanied by a significant heat exchange Q: there is cooling when the gas is released and release of heat when the gas attaches to the salt.

Depending on the nature of the latter, the equilibrium curve 27 is different, as is the heat of reaction given off: for a first approximation, however, the heat of reaction between the salt and the gas is two to five times more for ammonia. large than the heat given off when the liquid / vapor state of ammonia changes
NH3.

 Suppose that the reactor 1 as shown in FIGS. 2 and 3 is in equilibrium at point A at a temperature of 200 "C and at a pressure maintained at 20 bars maximum for example by an appropriate pressure reducer: if by means of a hot heat transfer fluid, the temperature of reactor 1 is increased beyond 200, the internal pressure of the reactor will therefore tend to increase in order to maintain the pressure / temperature balance on curve 27; this tendency to increase pressure above the 20 bar threshold set will therefore release the gas from the solid contained in the reactor: it will indeed release gas, such as ammonia, in an attempt to reach its equilibrium line 27 as long as there remains ammonia in reactor 1; the gas therefore leaves this reactor at a point A 'close to A, and at the pressure that has been limited in the reactor, for example 20 bars, and feeds an expansion circuit 3 as shown in Figure 2: at the At the end of this expansion phase, the gas is found at a point D 'at low pressure.

 If a second reactor 2 of the same type as the previous one is then connected and gas vacuum, which is then at a temperature, such as for example at 100 C corresponding precisely to an equilibrium point of the curve 27 for the pressure of the point D ', and if by means of a cool coolant the temperature of this reactor 2 is lowered below these 100 C the internal pressure of the latter will tend to decrease to maintain the equilibrium of the reaction on the curve 27: this then causes the adsorption by suction of the gas in this reactor which attempts to remain on the equilibrium curve 27. The reaction will stop when the reactor 1 will no longer contain any gas and the reactor 2 will have adsorbed all of this gas.

 FIGS. 2 and 3 are examples of diagrams of the principle of circulation of the heat-transfer fluid and of the gas: as regards FIG. 2, it is the gas circuit as according to FIG. 1; and in FIG. 3 of an example of a heat transfer fluid circulation network allowing a calorific supply to a reactor 1 and a cooling of the reactor 2 to allow their operation according to the diagram of FIG. 1.

The mechanical energy production device according to the present invention thus comprises
- At least two thermochemical reactors 1, 2 can either fix said gas at low pressure, or release this gas at higher pressure according to its temperature, as defined above;
- According to Figure 2, at least one supply circuit 8 of said gas connecting at least the two reactors 1, 2 through a turbine 3 expansion;
- And according to Figure 3, at least one heat transfer fluid circulation network 11, 24, connecting and looping, on the one hand and respectively on a hot source 10 at least one of the two reactors 1 then releasing the gas and, on the other hand, on a cold source 23 at least one other reactor 2 which thus absorbs the gas released by the first.

 The hot source can be, as indicated above, fumes given off by any type of engine or by a boiler, transferring their heat energy through any type of exchanger to the heat transfer fluid which it heats; depending on the type of use, the gases or fumes given off by the hot source can go directly through the circulation network 11 to go directly to heat the reactors 1 or 2.

 The cold source 23 can be on the ambient medium such as air or water, or any other source of evacuation of calories at a low temperature, thanks, as for the hot source, to an exchanger in which the heat transfer fluid circulates. which is cooled there. The cold circuit 24 connecting the cold source to one of said reactors 1 and 2, can be, as the case may be, passed directly by the external coolant fluid, without a secondary circuit and then without exchangers 23.

 In FIG. 2, the feed gas supply circuit 8 of the turbine 3 can comprise a certain number of shut-off valves 6 so as to be able to isolate each item of equipment from each other, and at least one filter 28 and regulating members and pressure and temperature control at the inlet / outlet of each of the reactors.

 This circuit 8 can also comprise, if necessary, desuperheaters 4 cooled by a possible water circuit 9, so as to lower the temperature of the gas leaving the reactors 1 or 2, before sending it to the turbine 3.

 Each of the parts of circuits each connected to an inlet / outlet of reactors 1 and 2 comprises at least two branches each comprising a non-return valve 5, depending on the pressure, oriented one to allow the return of gas from the outlet of the turbine 3 and the other for the evacuation towards the entry of this one, and prohibiting the reciprocity on the same derivation of course.

 If it is reactor 1 which is therefore at a pressure higher than that of reactor 2, and which contains gas to be released, it will exit from this reactor 1 through the non-return valve 51 towards the supply circuit of the turbine 8, the non-return valves 52 and 53 preventing it from supplying the reactor 2 directly. The latter then has a lower pressure and being able to absorb gas, receives the latter through the single non-return valve 54 authorizing its filling.

 At the end of this first production phase, the reactors 1, 2 are inverted as indicated above according to the method of the invention, the reactor 2 then becoming the gas supplier reactor and the reactor 1 that adsorbing it. For this, it is therefore necessary to heat the reactor 2 and cool the reactor 1 as indicated in FIG. 3 until there is a pressure and temperature inversion in the reactors.

 To accelerate this pressure and temperature reversal and allow, even if this is to the detriment of the yield, a rapid restart of the production phase, the gas supply circuit as shown in FIG. 2 between the at least two reactors 1, 2 can comprise at least one bypass 7, making it possible to short-circuit the part of the circuit supplying the turbine 3 as well as all of the non-return valves, and then to directly connect the inputs / outputs of the reactors 1 and 2: this thus promotes bringing them into equilibrium at the same pressure and therefore also at the same temperature, between points A and D on curve 27 of FIG. 1; then after this equilibrium, the two reactors are isolated by the circuit 7 and it is the cold and hot sources for their circulation network of heat transfer fluid 11, 24 which bring the reactor 1 respectively to point D and the reactor 2 to point A.

 According to FIG. 2, the gas is then re-circulated from the reactor 2 to the reactor 1 by the opening of the non-return valves 53 and 52 respectively instead of the 51 and 54.

 According to FIG. 3 and in the case where an identical heat transfer fluid is used to heat the reactors or to cool them, said heat transfer fluid circulation network 11, 24 consists of a single network of exchangers and circulation of the same fluid , but isolable by valves in at least two parts connected alternately to said cold and hot sources, and in which circulate alternately and respectively the hot fluid in a reactor 1 and the cold fluid in the other reactor 2.

 However, if it is desired to directly use at least one of two external fluids supplying the heat energy on one side or on the contrary discharging the heat energy on the other, said heat transfer fluid circulation network 11, 24 may comprise at least two distinct networks of exchangers and circulation of heat transfer fluid, one for cooling, the other for heating.

 The network of hot fluid li therefore comprising the hot source 10, can also include a circulation pump 29 to force the hot fluid to circulate at a certain speed, various temperature and pressure control members not shown, and a degasser 12, as well as various valves 14, 15, 16, 17 making it possible to isolate part of the network and to open the other part so that the hot fluid circulates on only one of the two reactors 1 or 2.

 The cold fluid network 24 may also include a circulation pump 22, possibly as said previously an air cooler 23 of the fluid which then serves as a cold source, various optional filters 28 and regulating and controlling members for temperature and pressure not shown, and isolation valves 18, 19, 20, 21 of a part of the network then looped on one of the two reactors 1 or 2, while the other is looped on the hot circuit 11.

 Thus, during a first phase of mechanical energy production during which the reactor 1 is heated and in desorption and the reactor 2 is cooled and in adsorption, the valves 17, 15, 19 and 21 are closed while the valves 16 , 14, 18 and 20 are open, the pumps 1 and 2 then being in operation and the bypass valve 13 as described below is of course closed.

 As indicated in the diagram in FIG. 1, the reactor 1 is then at high pressure and the reactor 2 at low pressure, and therefore the valves 53 and 52 are closed, the valves 51 and 54 are open.

 The gas, which can therefore be a refrigerant, is then released from the reactor 1 to become fixed in the reactor 2, and on passing through the turbine 3, it expands producing mechanical energy. The end of this phase is detected when the reactor 2 is full or when the reactor 1 is empty. For this, a weight sensor can be used, for example, or a measurement of lack of heat exchange when the difference between the inlet and outlet temperature of the heat transfer fluid by the reactor 2 is small, while the pressure of gas suction is high and / or when the difference in the inlet and outlet temperature of the heat transfer fluid for the reactor 1 is small while the gas discharge pressure is low.

 At the end of this first phase of energy production, it is then necessary to pass to a reactor inversion phase, during which the valves 16, 14, 15, 18, 19 and 21 can be closed the valves 17 and 20 are open, the pump 22 remains in operation while the pump 29 is stopped, and the bypass valve 13 can be opened, as well as the bypass circuit of FIG. 2 between the inputs and refrigerant gas outlets.

 This bypass circuit 25 between the two parts of the network of the heat-transfer fluid makes it possible to isolate a part of it, putting said fluid into circulation only with the two reactors 1 and 2; in the example of circuit shown, the cold source 23 is also bypassed by the valve 30 directly connecting the inlet and outlet pipes of the cold source. This then allows an external heat exchange between the two reactors and thus bring them more quickly to an equilibrium temperature.

 The two combined actions of the two bypass systems 25 and 7 in FIG. 3 and in FIG. 2 mean that this inversion phase is shortened over time. The end of this phase is detected when the two reactors are at substantially the same temperature and at the same pressure, knowing that to improve the energy efficiency of the installation, it is certainly possible to allow the bypass valve 7 installed on the refrigerant gas circuit between the two reactors 1 and 2, but then the inversion time of the two reactors will be longer.

 This phase 2 inversion can also be completely eliminated and go directly to the next second phase of energy production, but in this case the inversion time of the two reactors will certainly be shorter, but to the detriment of the energy balance of the system: practical, this solution will only be used if the energy from the hot source 10 is free, as during recovery of calories lost in the flue gases.

 To pass to the second phase of production of mechanical energy, during which the reactor 1 is then in adsorption and cooled and the reactor 2 in desorption and heated, and so that the gas or refrigerant is released from the reactor 2 and comes to be fixed on reactor 1 by driving the turbine 3 for the production of mechanical energy, the valves 16, 14, 18 and 20 are closed while the valves 17, 15, 19 and 21 are open, the circulation pumps 22 , 29 then being in operation, and the bypass valves 13 and 7 closed. The reactor 2 is then at high pressure, and the reactor 1 at low pressure, and therefore the valves 51 and 54 are closed and the valves 52 and 53 are open as described in FIG. 2.

 This second phase of mechanical energy production takes place in the same way as the first previous phase, and at the end of this phase, which can be detected like the previous one, the reactors 1 and 2 are again reversed, as described previously, and the operations are repeated as long as one wishes to obtain this production of mechanical energy.

 In FIG. 3, it is also represented in the circulation network of the isolation valves 6 of the various items of equipment, as well as possible filters 28 and various other temperature pressure sensors and regulating members, are not shown while they are of course necessary for the control of all the preceding operations.

 In the case of the use of gaseous and pressureless heat transfer fluid in the circuits 11, 24, the pipes are of course replaced by ducts and the valves by air flaps.

 For certain applications, depending on the material chosen, three-way valves can be used rather than two-way valves as shown in the diagrams.

As regards the construction and the shape of the actual reactors, this may be different depending on the type of applications desired, the unit powers and the storage capacities of gases, such as ammonia. They can mainly have the following forms
- of multitubular type with calender and tubes, the tubes being able to be straight, hairpin or spiraled and fixed on a tubular plate or two tubular plates. The solid reagent can be placed inside the tubes or outside them ci and the heating and cooling fluids that can circulate inside the tubes if the reagent is outside or outside the tubes if the reagent is inside:
- of plate type with incorporation of the reagent between the exchanger plates;
- of the multitubular type with exchanger plates inside the calender, the reagent being attached to the outside of the plates and the heating or cooling fluids circulating inside them.

 Furthermore, in the example of FIG. 3, the reactors 1 and 2 have a single circuit for ensuring the internal heat exchange, sometimes the hot heat transfer fluid is then passed there, sometimes the cold heat transfer fluid is passed through it such that previously described.

 However, depending on the applications, reactors can be used with an internal or external double exchange circuit between the fluids and the reactants, which makes it possible to produce two distinct circulation networks, one for cooling, the other for heating. and thus to use possibly different heat transfer fluids.

For example, these heating and cooling fluids can be fluids
- using sensible heat to supply or remove calories such as water, thermal fluids, oil, mixtures of fluids, air, etc.

 - using latent heat to supply or dissipate calories such as water, steam, ammonia etc ...

 - mixtures using the absorption property one inside the other, to provide or remove calories such as air + water, water + salt, ammonia + water etc ...

 It is also possible to design a mode of radiant heating by integrating a heating flame directly into the reactors 1, 2, making it possible to eliminate the circuit 11 of hot fluid.

 Furthermore, if the temperature difference between the hot source and the cold source allows, reactors can be used with at least two different salts, which would improve the efficiency of the installation.

 Similarly, in other embodiments in which more continuous production is desired, a third reactor can be added and by cleverly cycling the three said reactors, the production of mechanical energy is perfectly continuous.

 Similarly, if one wishes to have installations which make it possible to produce mechanical power at high power, it is possible to install several reactors in parallel according to the same methods and the same devices, as described above, according to the invention.

Claims (10)

 1. Method for producing mechanical energy from a hot source (10), characterized in that  - At least one first thermochemical reactor (1) capable of releasing or adsorbing gas is heated according to its temperature and its pressure, using the calories released by said hot source (10);  - the gas released by the heating of this reactor (1) is recovered to a given pressure, and the inlet of a pressure reduction turbine (3) is fed therefrom, from which it exits at lower pressure and at lower temperature after having driven it in rotation;  - this expanded gas is then recovered in at least one second thermochemical reactor (2), of the same type as the first, where it is adsorbed or chemically bound, by releasing heat which is removed using any cold source (3 ), which keeps this at least second thermochemical reactor (2) at a lower temperature than that of the at least first thermochemical reactor (1).  2. A method of producing energy according to claim 1, characterized in that at the end of the phase of liberation of the gas from the first reactor (1) and of adsorption of this gas by the second reactor (2), these two reactors by heating the second by the hot source (10) so that it in turn releases said gas which it adsorbed in the previous phase, and by cooling the first by the cold source (23) so that it then adsorbs in turn the gas released by the other after expansion and drive of the turbine (3).  3. A method of producing energy according to any one of claims 1 or 2, characterized in that the two at least reactors (1 and 2) are connected by at least two circulation networks, one in heat transfer fluid. (11, 24) and the other in reaction gas (8), the first network connecting and looping, on the one hand, a circuit between the hot source (10) and at least that of said reactors (1) which releases the gas, and on the other hand, another circuit between the cold source (23) and at least that of said reactors (2) which adsorbs the gas, and the second network connecting the two reactors (1 and 2) to each other, through the turbine (3).  4. A method of producing energy according to claim 3, characterized in that  - The at least two gas inlets / outlets of the at least two reactors (1 and 2) are directly connected by a circuit (7) short-circuiting the turbine (3) and which is closed during the energy production phases by expansion of the gas released from at least one reactor;  - said circuit (7) is opened at the end of each mechanical energy production phase, when the cold reactor (2) has adsorbed the gas released by the hot reactor (1) and the latter is then emptied in large quantities part of this gas.  5. Device for producing mechanical energy from a hot source (10) and using an expansion turbine (3), characterized in that it comprises  - at least two thermochemical reactors (1 and 2) which can either fix a gas at low pressure, or release this gas at higher pressure according to its temperature;  - At least one heat transfer fluid circulation network (11, 24) connecting and looping, on the one hand and respectively on the hot source (10) at least one of the two reactors (1) then releasing gas, and on the other leaves on a cold source (23) at least one other reactor (2) which thus absorbs the gas released by the first;  - At least one supply circuit (8) of said gas connecting at least the two reactors (1, 2) through said turbine (3).  6. An energy production device according to claim 5, characterized in that said reactors (1 and 2) and said heat transfer fluid circulation network (11, 24) consists of at least two distinct networks of exchangers and circulation of heat transfer fluids, one for cooling, the other for heating.  7. Energy production device according to claim 5, characterized in that said reactors (1 and 2) and said heat transfer fluid circulation network (11 and 24) consists of a single network of exchangers and circulation of the same fluid, but isolable by valves in at least two parts connected alternately to said cold and hot sources, and in which circulate alternately and respectively the heating fluid in one of the two reactors (1) and the cold fluid in the other reactor (2 ).  8. An energy production device according to any one of claims 5 to 7, characterized in that the gas supply circuit (8) between the at least two reactors (1, 2) comprises a bypass (7) allowing to short-circuit the turbine (3) and to directly connect the inputs / outputs of said reactors.  9. Energy production device according to any one of claims 7 and 8, characterized in that the heat transfer fluid circulation network (11, 24) can be isolated in one part allowing the circulation of the fluid only between the two reactors (1, 2).  10. Application of thermochemical reactors which can either fix a gas at low pressure, or release this gas at higher pressure according to its temperature, characterized in that at least two of said reactors (1, 2) are connected, one heated by to any hot source (10) and the other cooled by any cold source (23) by a supply circuit of said gas comprising an expansion turbine (3), making it possible to produce mechanical energy by its rotation .