Reactive working fluids for cyclic thermodynamic conversion machines and cyclic thermodynamic conversion machines comprising said working fluid

Abstract

Reactive working fluid for cyclic thermodynamic conversion machines, said working fluid, comprising a monomer / dimer couple capable of reversibly associating / dissociating, during each thermodynamic cycle, by covalent bond(s) formation / breakage; said monomer / dimer couple being of formula 2(Ri-Xº) / Ri-X- X-Ri, wherein Ri is / are substituent(s) bonded to each atom X, i being equal to 1, 2, 3, 4, 5 or 6, each Ri is different from X, j is the number of substituent(s) Ri bonded to each atom X, j being comprised between 1 and 6, each Ri and X are selected from F, Cl, Br, I, O, S, B, N, P and C, each Ri is an atom at its lowest valence state; and for j equal to 1: X is O, and R1 is F, Cl, Br or I, or X is S, and R1 is F, Br or I, or X is B, P, N, Cl, Br or I, and R1 is O, or X is B, P, N, Br or I, and R1 is S; and for j equal to 2: X is selected from B, P, N, Cl, Br or I, and R1 and R2 are selected from F, Cl, Br, S or I, or X is selected from B, P, Cl, Br or I, and R1 and R2 are selected from F, Cl, Br, S, O or I.

Description

« Reactive working fluids for cyclic thermodynamic conversion machines andcyclic thermodynamic conversion machines comprising said working fluid »Field of the invention

[0001] The present invention relates to the field of working fluids.

[0002] In particular, the present invention deals with a working fluid intended tobe used in thermodynamic cycles.

[0003] The present invention also relates to cyclic thermodynamic conversion ma-chines.

[0004] Especially but not exclusively, the present invention deals with heat pumps,refrigeration machines and power plants / engines.Background to the invention

[0005] Thermodynamic machines are based on the cyclic conversion of one ormore types of energy entering these machines into another type of useful energy.In thermodynamic machines, the different forms of energy exchanged with theenvironment are internally converted one in another by an energy vector, theworking fluid.

[0006] The working fluids of the state of the art can be organic or inorganic. Themost commonly used working fluids are water in steam power plants, air and com-bustion products in gas turbines, and organic refrigerants in heat pumps and re-frigeration cycles. Ideally, a working fluid should be chemically stable, that is, noirreversible chemical reaction, in particular side reaction, should take place alongthe thermodynamic cycle of energy conversion.

[0007] However, if used outside their thermal stability range, the organic workingfluids of the state of the art tend to form new compound(s) through irreversibleside reactions over thermodynamic cycles, which results in a decreased efficiencyof the thermodynamic machine.

[0008] Each type of thermodynamic machine will exhibit different operatingmodes. Nevertheless, the working fluid in a thermodynamic machine will usuallychange its thermodynamic properties according to a thermodynamic cycle com-prising four thermodynamic transformations. It may also exist several variants ofthe operating mode for a same type of the thermodynamic machines. In powerplants, the working fluid may follow either a Rankine cycle, or a Brayton cycle, ora Stirling cycle, in each of which it undergoes at least four successive thermody-namic transformations. In heat pumps and refrigeration machines, the workingfluid follows an inversed thermodynamic cycle in which it undergoes at least foursuccessive thermodynamic transformations.

[0009] In each case, the energy to be provided to the cyclic thermodynamic con-version machine for the operation is in the form of mechanical energy, and thermalenergy. Usually, the mechanical energy is provided to the system by a pump or acompressor powered by electrical or mechanical energy. The thermal energy isprovided to the cycle by an external heat source and through a heat exchanger.In heat pumps and refrigeration machines operating in refrigeration / heating modeand most of power plants, the electrical or mechanical energy will be used to com-press the working fluid. In heat pumps, and refrigeration machines operating in refrigeration / heating mode and most of power plants, the input thermal energy will be used to heat up the working fluid. The useful effect is the quantity of thermalenergy transferred to the environment to be heated, in the case of heat pumps,or the quantity of thermal energy removed from the environment to be cooled down, in the case of refrigeration systems, or the quantity of mechanical energy released during the expansion process.

[0010] It still remains a strong need to increase the performance of thermody-namic machines.Summary of the invention

[0011] An object of the invention is to provide working fluids:- overcoming the drawbacks of the working fluids of the state of the art,- allowing to decrease the operating cost of the thermodynamic machines of thestate of the art,- allowing to decrease the size of the thermodynamic machines of the state of theart, and / or- allowing to increase performance of the thermodynamic machines of the state ofthe art.

[0012] Another object of the invention is to provide cyclic thermodynamic conver-sion machines:- overcoming the drawbacks of the thermodynamic machines of the state of theart,- with lower operating costs,- having smaller sizes, and / or- having higher yield and performances compared to the thermodynamic machinesof the state of the art.

[0013] To this end, there is provided a reactive working fluid for cyclic thermody-namic conversion machines, said working fluid, comprising a monomer / dimer cou- ple. The working fluid may be described as forming a monomer / dimer couple.Preferably, the working fluid comprises, or may consist in, one or a mixture ofmonomer / dimer couple(s). The monomer / dimer couple is capable of reversibly as-sociating / dissociating, during each thermodynamic cycle, by covalent bond(s) for- mation / breakage.

[0014] Preferably, the monomer / dimer couple or each of the monomer / dimer cou-ple of the mixture is of formula 2(Ri-X•) / Ri-X-X-Ri.

[0015] Preferably, Ri is / are substituent(s) bonded to each atom X. Preferably, i isequal to 1, 2, 3, 4, 5 or 6.

[0016] Each different Ri may be a different atom. For instance, R1 may be differentfrom R2 (and may be different from R3, R4 and R5); the same applies mutatis mu-tandis for R2, R3, R4, R5 and R6.

[0017] Preferably, j is the number of substituent(s) Ri bonded to each atom X.Preferably, j is comprised between 1 and 6.

[0018] Preferably, each Ri is different from X.

[0019] Preferably, one considered substituent (Ri) is different from or identical toanother, several or each of the other substituents.

[0020] Preferably, each Ri and X are selected from F, Cl, Br, I, O, S, B, N, P andC.

[0021] Preferably, each Ri is an atom at its lowest valence state.

[0022] Preferably, for j equal to 1, that is R1-X-X-R1:- X is O, and R1 is F, Cl, Br or I,- X is S, and R1 is F, Br or I,- X is B, P, N, Cl, Br or I, and R1 is O, and / or- X is B, P, N, Br or I, and R1 is S.

[0023] Preferably, for j equal to 2:- X is selected from B, P, N, Cl, Br or I, and- R1 and R2 are selected, preferably independently selected, from F, Cl, Br, Sor I.

[0024] Preferably, for j equal to 2:- X is selected from B, P, Cl, Br or I, and,- R1 and R2 are selected, preferably independently selected, from F, Cl, Br, S,O or I.

[0025] Preferably, the two atoms X of a / each dimer of a / each considered mono-mer / dimer couple are the same atom.

[0026] The index i may be identical or may different from the number j of substit-uent bonded to each atom X. The index i may be lower than or equal to the number j of substituent bonded to each atom X.

[0027] Preferably, j is equal to 1, 2, 3, 4, 5 or 6, more preferably to 2, 3, 4, 5 or6 and even more preferably to 3, 4, 5 or 6.

[0028] Preferably, the number j of substituent(s) Ri bonded to each atom X is thesame for each atom X of a considered couple, preferably for each atom X of a / each monomer of a considered couple and for each atom X of a / each monomer of a considered couple.

[0029] A cyclic thermodynamic conversion machine is said thermodynamic ma-chine.

[0030] Preferably, a monomer, more preferably each monomer of each mono-mer / dimer couple, is of formula Ri-X•.

[0031] “X•” is a radical. Preferably, “X•” is an atom with one single unpaired va-lence electron.

[0032] Preferably, a dimer, more preferably each dimer of each monomer / dimercouple, is of formula Ri-X-X-Ri.

[0033] Preferably, each X and each Ri are an atom, more preferably one singleatom. Preferably, X and Ri are not or are different from a chemical group. It maybe understood by chemical group a group of atoms.

[0034] Preferably, the number j of substituent(s) Ri bonded to each atom X of amonomer / dimer couple, preferably of each monomer / dimer couple, is equal to 1,2, 3, 4, 5 or 6. Preferably, the number j of substituent(s) Ri bonded to the atom Xof a monomer, preferably of each monomer of each monomer / dimer couple, is equal to 1, 2, 3, 4, 5 or 6.

[0035] Preferably, the number of substituent(s) Ri of a / each dimer, preferably ofa / each dimer of a / each monomer / dimer couple, is equal to 2, 4, 6, 8, 10 or 12. Preferably, the number of substituent(s) Ri of a / each dimer, preferably of a / each dimer of a / each monomer / dimer couple, is equal to j / 2.

[0036] Preferably, a / each monomer / dimer couple, more preferably a / each mono-mer and / or a / each dimer, even more preferably a / each monomer and / or a / each dimer of a / each monomer / dimer couple, comprises up to three different atoms. Preferably, a / each monomer / dimer couple, more preferably each monomer and each dimer of a / each monomer / dimer couple, comprises one and the same atom (i.e. each substituent (Ri) is the same atom), two different atoms or three different atoms.

[0037] Preferably, the substituents (Ri) of a / each monomer / dimer couple, the setof substituents (Ri) of a / each monomer / dimer couple or the whole of the substit-uents (Ri) of a / each monomer / dimer couple comprises, more preferably consistsof: -a single atom (for j equal to 1), or- one and the same atom (for j equal or higher than 2), or- two different atoms (for j equal or higher than 2).

[0038] One considered substituent (Ri) of a / each monomer:- may be identical to each other substituents (for j equal or higher than 2),to several other substituents (for higher than 2) or to the other substituent(for j equal to 2) or to one other substituent (for j equal or higher than 2),and / or -may be different from the other substituent (for j equal to 2) or from oneother substituent (for j equal or higher than 2) or from several other sub-stituents (for j higher than 2) or from any other substituent (for j equal orhigher than 2).

[0039] One considered substituent (Ri) of a / each dimer:- may be identical to each other substituents, to several other substituents,to the other substituent, and / or- may be different to the other substituent (for j equal to 1) or to severalother substituents for j equal or higher than 2.

[0040] Preferably, X as a valence comprised between 2 and 7.

[0041] Preferably, X has valence equal to 2, 3, 4, 5, 6 or 7, more preferably to 3,4, 5, 6 or 7 and even more preferably to 4, 5, 6 or 7.

[0042] The working fluid may be defined as, or may comprise, a chemical com-pound. The compound may be defined as, or may consist in, the monomer, that is the working fluid in its dissociated form, or may be defined as, or may consist in, the dimer, that is the working fluid in its associated form.

[0043] This invention can be defined as working fluids or compounds, used or in-tended to be used in thermodynamic machines, having the particularity of being reactive, over the phases of one thermodynamic cycle, instead of being inert. Itcan be understood by reactive working fluids or compounds: fluids having thechemical property of reversibly associating / dissociating, preferably to form di- mer / monomer respectively, during at least two phases of each thermodynamic cycle, more preferably during each thermodynamic cycle.

[0044] Preferably, the working fluid or the compound dissociates or associates, toform monomers or to form dimers respectively, during each phase of the thermo- dynamic cycle. Preferably, the working fluid or the compound dissociates and as- sociates, to form monomers and to form dimers respectively, during at least two phases of each thermodynamic cycle, more preferably during each thermodynamic cycle.

[0045] Preferably, the working fluid or the compound reversibly associates / disso-ciates over phases, or thermodynamic phases, of each thermodynamic cycle. A thermodynamic phase may be described as a thermodynamic transformation that the working fluid undergoes during the thermodynamic cycle. A thermodynamic transformation may be described as a thermodynamic state change. The skilled person has the general knowledge to figure out the four transformations carried out during a given thermodynamic cycle.

[0046] Preferably, each dimer Ri-X-X-Ri of the working fluid reversibly dissociatesinto two monomers Ri-X•of the working fluid, during at least one phase of eachthermodynamic cycle, and two monomers Ri-X• of the working fluid reversibly as-sociates into one dimer Ri-X-X-Ri of the working fluid, during at least another phaseof each thermodynamic cycle, as follows: Ri-X-X-Ri ⇋ 2(Ri-X•).

[0047] The working fluid or the compound may undergo or may be able to or maybe arranged to undergo: -a dissociation, at least partly, into monomers during a compression phaseof the thermodynamic cycle, -an association, at least partly, into dimers during a cooling phase of thethermodynamic cycle, -an association, at least partly, into dimers during an expansion phase of thethermodynamic cycle, -a dissociation, at least partly, into monomers during a heating phase of thethermodynamic cycle.

[0048] According to the present description, it is understood by cooling phase andheating phase the cooling of the working fluid and the heating of the working fluid.

[0049] During the heating and / or the cooling phase, the working fluid may stay inthe same state of matter, in gaseous state for instance, or may change, partly or in its entirety, of state of matter, from gaseous to liquid and conversely.

[0050] When the working fluid undergoes a change of state of matter, which maybe partial or complete, during the heating and / or the cooling phase, the cooling phase may be referred to as condensation phase and the heating phase may be referred to as evaporation phase.

[0051] The cooling phase may comprise a condensation of the working fluid. Thecooling phase may be a condensation phase. The heating phase may comprise an evaporation of the working fluid. The heating phase may be an evaporation phase.

[0052] The working fluid or the compound used in a power Brayton or Rankinecycle may undergo or may be able to or may be arranged to undergo: -a dissociation, at least partly, preferably in its entirety, into monomers dur-ing a compression phase of the thermodynamic cycle, -an association, at least partly, preferably partly only, into dimers during acooling phase of the thermodynamic cycle,- an association, at least partly, preferably in its entirety, into dimers duringan expansion phase of the thermodynamic cycle, -a dissociation, at least partly, preferably partly only, into monomers duringa heating phase of the thermodynamic cycle.

[0053] The working fluid or the compound used in a heat pump may undergo ormay be able to or may be arranged to undergo: -a dissociation, at least partly, preferably in its entirety into monomers dur-ing a compression phase of the thermodynamic cycle, -an association, at least partly, preferably in its entirety, into dimers duringa cooling phase of the thermodynamic cycle, -an association, at least partly, preferably partly only, into dimers during anexpansion phase of the thermodynamic cycle, -a dissociation, at least partly, preferably partly only, into monomers duringa heating phase of the thermodynamic cycle.

[0054] The working fluid or the compound used in a refrigeration cycle may un-dergo or may be able to or may be arranged to undergo: -a dissociation, at least partly, preferably in its entirety, into monomers dur-ing a compression phase of the thermodynamic cycle, -an association, at least partly, preferably partly only, into dimers during acooling phase of the thermodynamic cycle, -an association, at least partly, preferably in its entirety, into dimers duringan expansion phase of the thermodynamic cycle, -a dissociation, at least partly, preferably in its entirety, into monomers dur-ing a heating phase of the thermodynamic cycle.

[0055] Preferably, the monomer / dimer couple is:, formula 1, wherein X isO, and R1 is F, Cl, Br or I; or X is S, and R1 is F, Br or I, preferably X has a valence2, and / or, formula 2, wherein X is B, P, N,Cl, Br or I and R1 and R2 is / are selected, preferably independently selected, fromF, Cl, Br and I, preferably X has a valence 3, and / or, for- mula 4, wherein X is N, and R1 and R2 is / are selected, preferably independentlyselected, from F, Cl, Br or I, and R3 is O, preferably X has a valence 3, preferablythe dimer / monomer couple of formula comprises dative bond(s), preferably the dimer comprises two dative bonds and the monomer comprises one dative bond, more preferably the dative bond(s) is between X and an R3-(the dative bond(s) are depicted by the black arrow(s) in formula 4 wherein the two electrons of thebond originate from X, and / or, formula 5,wherein X is N, and R1 is S, and R2 is O, preferably X has a valence 3, preferablythe dimer / monomer couple of formula comprises dative bond(s), preferably the dimer comprises two dative bonds and the monomer comprises one dative bond, more preferably the dative bond(s) is between X and an R2- (the dative bond(s) are depicted by the black arrow(s) in formula 5 wherein the two electrons of the bond originate from X,6,wherein X is C or S, and R1, R2 and R3 are selected, preferably independentlyselected, from F, Cl, Br and I, preferably X has a valence 4, and / or,formula 7, wherein X is C or S, and R1 is selected from O and S, and R2 is selectedfrom F, Cl, Br and I, preferably X has a valence 4, and / or, formula 8,wherein X is C or S, and R1 is selected from B, P and N, preferably X has a valence4, and / orindependently selected, from F, Cl, Br and I, preferably X has a valence 5, and / or,formula 10, wherein X is P, Cl, Br or I, and R1 is selected from O and S, and R2 andR3 are selected, preferably independently selected, from F, Cl, Br and I, preferablyX has a valence 5, and / or,formula 11, wherein X is P, Cl, Br or I, and R1 is selected from B, P, and N and R2is selected from F, Cl, Br and I, preferably X has a valence 5, and / or, for-mula 12, wherein X is P, Cl, Br or I, and R1 and R2 are selected, preferably inde-pendently selected, from O and S, preferably X has a valence 5, and / or,formula 13, wherein X is S, and R1, R2, R3, R4 and R5 are selected, preferablyindependently selected, from F, Cl, Br and I, preferably X has a valence 6, and / ormula 14, wherein X is S, and R1 is selected from O and S, and R2, R3 and R4 areselected, preferably independently selected, from F, Cl, Br and I, preferably X hasa valence 6, and / or,formula 15, wherein X is S, and R1 is selected from B, P and N, and R2 and R3 areselected, preferably independently selected, from F, Cl, Br and I, preferably X hasa valence 6, and / or, R4are selected, preferably, independently selected, from F, Cl, Br and I, preferably Xhas a valence 6, and / ormula 17, wherein X is S, and R1 is selected from B, P and N, and R2 are selected,preferably independently selected, from O and S, preferably X has a valence 6,and / or,formula 18, wherein X is selected from Cl, Br and I, and R1, R2, R3, R4, R5, R6 andR7 are selected, preferably independently selected, from F, Cl, Br and I, preferablyX has a valence 7, and / ororR5 are selected, preferably independently selected, from F, Cl, Br and I, preferablyX has a valence 7, and / ormula 20, wherein X is selected from Cl, Br and I, and R1 and R2 is O or S, and R3and R4, are selected, preferably, independently selected, from F, Cl, Br and I, pref-erably X has a valence 7, and / or, formula 21, wherein X is selected from Cl, Br and I, and R1, R2 and R3 are selected,preferably independently selected, from O and S, preferably X has a valence 7,and / or, for-mula 22, wherein X is selected from Cl, Br and I and R1 is B, P or N, and R2, R3and R4 are selected, preferably independently selected, from F, Cl, Br and I, pref-erably X has a valence 7, and / or, formula23, wherein X is selected from Cl, Br and I, and R1 and R2 are selected, preferablyindependently selected, from B, P and N, preferably X has a valence 7.

[0056] It may be understood by “independently selected”: selected independentlyof each other, that is Ri may be selected: to be identical to each other, so that oneRi is different from another Ri, so that one Ri is identical to another Ri, so that oneRi is different from several others Ri, so that one Ri is identical to several others Rior so that Ri are different from each other.

[0057] Preferably, monomers, more preferably each monomer of a couple, evenmore preferably each monomer of each couple, are radicals or in radical form,more preferably having a single unpaired valence electron.

[0058] Preferably, dimers, more preferably each dimer of a couple, even morepreferably each dimer of each couple, have only paired valence electrons, that isare not radicals, in other words have no unpaired valence electron.

[0059] According to the invention, unless otherwise specified, when Ri is selectedfrom a listed group of atoms, R1, R2, R3, R4, R5 and / or R6 are selected independently from one another among the listed group of atoms.

[0060] Preferably, the valence / valences of the atom(s) of each couple, preferablyof each monomer and each dimer, is: -Fluorine (F): 1, and / or- Chlorine (Cl): 1, 3, 5 or 7, and / or- Bromine (Br): 1, 3, 5 or 7, and / or- Iodine (I): 1, 3, 5 or 7, and / or- Oxygen (O): 2, and / or- Sulfur (S): 2, 4 or 6, and / or- Boron (B): 3, and / or- Nitrogen (N): 3, and / or- Phosphorus (P): 3 or 5, and / or- Carbon (C): 4.

[0061] Preferably, each substituent Ri of each monomer and dimer of each coupleis in its lowest valence.

[0062] The working fluid may comprise one monomer / dimer couple selected in thecouples of listed, that is of formula 1 to 23, or may comprise a mixture of mono-mer / dimer couples selected in the couples listed, that is of formula 1 to 23, or may consist of one monomer / dimer couple selected in the couples listed, that is of formula 1 to 23, or may consist in a mixture of monomer / dimer couples selected in the couples listed, that is of formula 1 to 23.

[0063] The working fluid may consist in one monomer / dimer couples or in a mix-ture of two or more monomer / dimer couples selected from the list, that is of for- mula 1 to 23.

[0064] Preferably, the monomer / dimer couple or each of the monomer / dimer cou-ples or the mixture of two or more monomer / dimer couples is selected from thelist of formulae 1 to 23.

[0065] Preferably, during each thermodynamic cycle, the monomer / dimer coupleundergoes at least one covalent bond formation and at least one covalent bond breakage. Preferably, during each thermodynamic cycle, the monomer / dimer cou- ple undergoes one, preferably a single, covalent bond formation and one, prefer- ably a single, covalent bond breakage.

[0066] Preferably, the working fluid is unable to form or to incur breakage of vander Waals bonds between dimers, between monomers and / or between monomersand dimers.

[0067] According to another aspect of the invention, there is also provided the useof the reactive working fluid according to the invention in a cyclic thermodynamicconversion machine.

[0068] According to another aspect of the invention, there is also provided the useof the reactive working fluid according to the invention in a heat pump, in a powerplant and / or in a refrigeration machine.

[0069] According to the invention, there is also provided a cyclic thermodynamicconversion machine comprising:- the reactive working fluid according to the invention,- means for compressing the reactive working fluid,- means arranged to cool down the reactive working fluid,- means arranged to expand the reactive working fluid, and- means arranged to heat up the working fluid.

[0070] Preferably, the thermodynamic machine operating in power mode is ar-ranged to: -dissociate, at least partly, preferably in its entirety, the working fluid intomonomers within the means for compressing the working fluid, -associate, at least partly, preferably partially only, the working fluid intodimers within the means arranged to cool down the working fluid, -associate, at least partly, preferably in its entirety, the working fluid intodimers within the means arranged to expand the working fluid, -dissociate, at least partly, preferably partly only, the working fluid into mon-omers within the means arranged to heat up the working fluid.

[0071] Preferably, the thermodynamic machine operating in heat pump mode isarranged to: -dissociate, preferably in its entirety, the working fluid into monomers withinthe means for compressing the working fluid, -associate, preferably in its entirety, the working fluid into dimers within themeans arranged to cool down the working fluid, -associate, preferably partly only, the working fluid into dimers within themeans arranged to expand the working fluid, -dissociate, preferably partly only, the working fluid into monomers withinthe means arranged to heat the working fluid.

[0072] Preferably, the thermodynamic machine operating in refrigeration mode, isarranged to: -dissociate, preferably in its entirety, the working fluid into monomers withinthe means for compressing the working fluid, -associate, preferably partly only, the working fluid into dimers within themeans arranged to cool down the working fluid, -associate, preferably in its entirety, the working fluid into dimers within themeans arranged to expand the working fluid, -dissociate, preferably in its entirety, the working fluid into monomers withinthe means arranged to heat the working fluid.

[0073] Preferably, a heating machine denotes or refers to a machine providingheating as useful effect and a refrigeration machine denotes or refers to a machine providing cooling as useful effect.

[0074] Preferably, the invention also provides a machine that reversibly operatesin heating mode and cooling mode, such as a reversible heat pump for example.

[0075] According to the present description, cyclic thermodynamic conversion ma-chines may refer to a thermal machine, or heat or thermal engine.

[0076] Preferably but not exclusively, according to the present description, thethermodynamic machine is a heat pump, a refrigeration machine, or a power plant. By power plant, it may be understood: the assembly of a power plant dedicated to power generation which is the seat of the thermodynamic cycle.

[0077] Preferably, the cyclic thermodynamic conversion machine is a heat pump,a power plant, or a refrigeration machine.

[0078] Preferably, the reactive working fluid according to the invention is intended,more preferably arranged, even more preferably specifically arranged, to be usedand / or be part of any cyclic thermodynamic conversion machine. Preferably, thereactive working fluid according to the invention is intended, more preferably ar-ranged, even more preferably specifically arranged, to be used and / or be part ofany cyclic thermodynamic conversion machine arranged to carry out four, prefer-ably successive, thermodynamic phases comprising, preferably, a compressionphase, a cooling phase, an expansion phase and a heating phase.

[0079] Preferably, the reactive working fluid according to the invention is intended,more preferably arranged, even more preferably specifically arranged, to be usedand / or be part of the cyclic thermodynamic conversion machine according to theinvention.

[0080] Preferably, the reactive working fluid according to the invention is part ofany cyclic thermodynamic conversion machine, more preferably is part of the cyclicthermodynamic conversion machine according to the invention.Brief description of the drawings

[0081] Further inventive objects, features and advantages will become apparentfrom the following detailed description of several embodiments of the invention with reference to the drawing, in which:- FIGURE 1 represents the schematic sectional view of a heat pump operatingmode, comprising a reactive working fluid according to the invention,- each of FIGURES 2, 4, 6, 8, 10 and 12 illustrates thermodynamic properties ofone different reactive working fluid according to the invention, wherein:^ FIGURES 2a), 4a), 6a), 8a), 10a) and 12a) illustrate the saturated liquidand vapour densities of each reactive working fluid as a function oftemperature, ^FIGURES 2b), 4b), 6b), 8b), 10b) and 12b) illustrate the saturationpressure of each reactive working fluid as a function of temperature,^ FIGURES 2c), 4c), 6c), 8c), 10c) and 12c) illustrate the pressure of eachreactive working fluid as a function of the molar fraction of the monomer inliquid phase x1, and the molar fraction of the monomer / dimer couple as afunction of the molar fraction of the monomer in gaseous phase y1,- each of FIGURES 3, 5, 7, 9, 11 and 13 illustrate further thermodynamic prop-erties of the same seven reactive working fluid of FIGURE 2, wherein: ^FIGURES 3d), 5d), 7d), 9d), 11d) and 13d) illustrate the saturated liquidand vapour entropy (s) of the reactive working fluid according to the tem-perature, ^FIGURES 3e), 5e), 7e), 9e), 11e) and 13e) illustrate the enthalpy ofvaporisation (ΔvapH) of the reactive working fluid according to thetemperature,- FIGURE 14 illustrates the saturated liquid and vapour entropy (s) of thepropane according to the temperature,- FIGURE 15 illustrates the enthalpy of vaporisation (ΔvapH) of the propaneaccording to the temperature.Detailed description of embodiments of the invention

[0082] The embodiments hereinafter described are not restrictive; other embodi-ments comprising a selection of features described hereinafter may be considered. A selection may comprise features isolated from a set of features (even if this selection is isolated among a sentence comprising other features thereof), if the selection is sufficient to confer a technical advantage or to distinguish the invention from the state of the art. This selection comprises at least a feature, preferablydescribed by its technical function without structural features, or with a part ofstructural details if this part is sufficient to confer a technical advantage or to distinguish the invention from the state of the art on its own.

[0083] In reference to FIGURE 1, it is described a working fluid 10 for cyclic ther-modynamic conversion machines 1 according to the invention. The working fluid 10 according to the invention is reactive during each thermodynamic cycle carriedout by the thermodynamic machine 1. The working fluid 10 comprises a monomer11 / dimer 12 couple. The working fluid 10 comprises a compound 12 capable of reversibly associating / dissociating, during each thermodynamic cycle, by for- mation / breakage of covalent bonds.

[0084] In other words, the atomic and / or molecular orbitals of the working fluid10 or the compound 12, which is of the monomers 12 and of the dimers 11, aremodified, at least partly, during each phases of the thermodynamic cycle.

[0085] According to the invention, the term “reactive” denotes the ability of thecompound 12 to reversibly associate / dissociate, during each phase of the thermo- dynamic cycle, to form a dimer 11 / monomer 12 respectively.

[0086] The working fluid 10 or the compound 12 undergoes, depending on thephase of the thermodynamic cycle and / or depending on the operating mode of thecyclic thermodynamic conversion machine (power, heat pump or refrigeration) inwhich the working fluid 10 according to the invention is used, partly only or atleast partly or in its entirety: -a dissociation into monomers 12 during a compression phase of thethermodynamic cycle, -an association into dimers 11 during a cooling phase of the thermodynamiccycle, -an association into dimers 11 during an expansion phase of the thermody-namic cycle, -a dissociation into monomers 12 during a heating phase of the thermody-namic cycle.

[0087] The nonrestrictive embodiment illustrated FIGURE 1 and detailed belowpertains to the use of the working fluid 10 according to the invention in a thermo- dynamic machine 1 operating in heating mode, a heat pump 1 for instance.

[0088] The working fluid 10 or the compound 12 after the compression phase ofthe cycle is completely, or at least mostly, in monomers 12 form.

[0089] During the cooling phase of the thermodynamic cycle, the working fluid 10or the compound 12 or the monomers 12 undergoes a complete association intodimers 11, or at least most of the compound 12 or the monomers 12 undergoesan association into dimers 11. After the cooling phase, the working fluid 10 pref- erably comprises only dimers 11, or comprises mostly dimers 11 and monomers 12 in a lower extent. During the cooling phase, according to the embodiment, the reactive working fluid 10 according to the invention allows to increase the heat quantity released to the environment, which is the useful effect. Indeed, duringthe cooling phase (that is the cooling of the working fluid 10 or the heating of theenvironment), the working fluid 10 undergoes an exothermic reaction due to the association of, most of, preferably the whole of, the monomers 12 into dimers 11. Thus, the efficiency of the energy conversion during the thermodynamic cycle is further increased.

[0090] During the expansion phase of the thermodynamic cycle, the working fluid10 or the compound 12 may undergo a further association of some of the mono- mers 12 into dimers 11. After the expansion phase, the working fluid 10 comprisesmonomers 12 and dimers 11. During the heating phase, the working fluid 10 un-dergoes an endothermic reaction due to the dissociation of, at least a part, the dimers 11 into the monomers 12. After the heating phase of the cycle, the working fluid 10 or the compound 12 is partly dissociated in dimers 11 form.

[0091] During the heating phase of the thermodynamic cycle, the working fluid 10or the compound 12 or the dimers 11 undergoes a dissociation into monomers 12. After the heating phase, the working fluid 10 comprises monomers 12 and dimers 11.

[0092] Indeed, during the heating phase (that is the heating of the working fluid10 or the cooling of the environment), the working fluid 10 undergoes an endo- thermic reaction due to the dissociation of only a part of the dimers 11 into mon- omers 12. Thus, the efficiency of the energy conversion during the thermodynamic cycle is further increased.

[0093] During the compression phase of the thermodynamic cycle, the workingfluid 10 or the compound 12 or the dimers 11 undergoes a complete dissociation into monomers 12, or at least most of the compound 12 or the monomers 12 undergoes a dissociation into dimers 11.

[0094] The compression phase is described and applies regardless the operatingmode of the cyclic thermodynamic conversion machine in which the working fluid 10 according to the invention is used. In other words, during the compression phase of the working fluid 10 according to the invention used in any cyclic ther- modynamic conversion machine operating in heating or in cooling or in power mode, the reactive working fluid 10 according to the invention allows to decrease the quantity of energy required for the compression of the fluid (that is the energy required to carry out the thermodynamic cycle). Indeed, during the compression of a reactive working fluid 10 according to the invention, the working fluid 10 undergoes an endothermic reaction due to the dissociation of, at least a part but preferably the whole of, the dimers 11 into monomers 12. In general, the com-pression of a fluid increases its temperature. However, the endothermic reactionthat takes place during the compression phase tends to reduce the temperature increase the working fluid 10 cold. Thus, since the compression of a colder fluidrequires less energy than the compression of a hot fluid, the efficiency of the ther-modynamic cycle is further increased.

[0095] According to the present description, the environment or external environ-ment, denotes the fluid, preferably the gas, preferably the surrounding atmos- phere, in which the working fluid 10, preferably the component in which the work- ing fluid 10 is circulating during the cooling phase and / or the heating phase. As a non-limiting example, the component in which the working fluid 10 circulates, or is intended to circulate, during the cooling phase and / or the heating phase is a heat exchanger.

[0096] According to the embodiment, the compound 12 is organic or inorganic.

[0097] Preferably, the reactive working fluid 10 according to the invention doesnot undergo, and is preferably not capable of, Van der Waals bonds for-mation / breakage between monomers 11 and / or dimers 12. More preferably, mon-omers 11 do not undergo association, and are preferably not capable of associat-ing, through Van der Waals bonds formation, in one or more dimers 12 and / ordimers 12 do not undergo dissociation, and are preferably not capable of dissoci-ating, through Van der Waals bonds breakage, in two or more monomers 11. Thereactive working fluid 10 according to the invention may not undergo, and may not be capable of, Van der Waals bonds formation / breakage between two or moremonomers 11 and / or between two or more dimers 12.

[0098] The compound (dimer) 12 is of formula Ri-X-X-Ri. The monomer is of for-mula Ri-X•. Ri is / are substituent(s) bonded to each atom X, i being equal to 1, 2,3, 4, 5 or 6, and each Ri is different from X. Each Ri and each X are single atom.Each monomer 11 and dimer 12 have a number j of substituent(s) Ri bonded to each atom X. J is comprised between 1 and 6. Each substituent Ri and each X are selected from F, Cl, Br, I, O, S, B, N, P and C. Each Ri is an atom at its lowest valence state.

[0099] During at least one phase of each thermodynamic cycle (that is one or twophase), the dimers Ri-X-X-Ri of the working fluid 10 reversibly dissociates, partlyor in their entirety, into two monomers Ri-X• of the working fluid 10 and during atleast one other phase of each thermodynamic cycle (that is one or two otherphases), two monomers Ri-X• of the working fluid 10 reversibly associates, partlyor in their entirety, into one dimer Ri-X-X-Ri of the working fluid 10 as follows: Ri-X-X-Ri ⇋ 2(Ri-X•).

[0100] According to the invention:- Ri is / are substituent(s) bonded to each atom X, i being equal to 1, 2, 3, 4,5 or 6, -each Ri and X are selected from F, Cl, Br, I, O, S, B, N, P and C,- each Ri is different from X,- each Ri is an atom at its lowest valence state,- j is the number of substituent(s) Ri bonded to each atom X, j being com-prised between 1 and 6.

[0101] According to the invention, the monomer 11 / dimer 12 couple is selectedfrom the list of formulae 1 to 23 previously described. In the present description,the set or the group of monomer 11 / dimer 12 couples corresponding or matchingone formula of the list is called a family of monomer 11 / dimer 12 couples. There-fore, the invention comprises 23 families of monomer 11 / dimer 12 couples, eachfamily being defined by one of the formulae 1 to 23.

[0102] According to a non-limiting embodiment, in order to simplify calculationsand the description of the invention, the working fluid 10 consists in a single mon- omer 11 / dimer 12 couple. However, the invention is not limited to a working fluid 10 consisting in a single monomer 11 / dimer 12 couple: -the working fluid 10 may comprise a mixture of monomer 11 / dimer 12 cou-ple according to the invention, and / or -the working fluid 10 may comprise mostly monomer 11 / dimer 12 coupleaccording to the invention, typically (in mass percentage) 70% or more,more preferably 80% or more, even more preferably 90% or more and inpreferred manner 95% or more, of monomer 11 / dimer 12 couple accordingto the invention and 30% or less, preferably 20% or less, even more pref-erably 10% or less and in preferred manner 5% or less, respectively, ofinert additive.

[0103] According to the non-limiting embodiment, in order to simplify calculationsand the description of the invention, each monomer 11 and each dimer 12, com- prises up to three different atoms, that is: -for j comprises between 1 to 6, each substituents Ri of each monomer 11and each dimer 12 are identical, that is each monomer 11 and each dimer 12 of the working fluid 10 comprises two different atoms (X and Ri) and all the substituents Ri are identical (consist in one and the same atom), or- for j≥2, each monomer 11 and each dimer 12 of the working fluid 10 com-prises three different atoms (one atom for X and two different atoms for Ri) and the substituent Ri of each monomer 11 and each dimer 12 consistin two different atoms (that is one Ri is different from one or several otherRi and one or several Ri may be identical to one or several other Ri).

[0104] According to the non-limiting embodiment, the 23 families comprise 492monomer 11 / dimer 12 couples.

[0105] At last, still for the sake to simplify calculations and the description of theinvention, the monomer 11 / dimer 12 couples comprising Iodine (I) are not con-sidered in the non-limiting embodiment.

[0106] Thus, from this further limitation, the 23 families comprise 262 monomer11 / dimer 12 couples.

[0107] According to a first improvement of the non-limiting embodiment, and stillfor the sake to simplify calculations and the description of the invention, only themonomer 11 / dimer 12 couples being stable have been considered.

[0108] By “stable”, it is understood: the dimers 12 and the monomers 11 do notevolve or degenerate into molecular structures other than the dimers 12 and themonomers 11. Also, the covalent bonds linking the central atom(s) X to the pe-ripheral atom(s) Ri do not break.

[0109] To that end, a first selection criterion applied to select, among the 492monomer 11 / dimer 12 couples, the monomer 11 / dimer 12 couples considered asstable according to the non-limiting embodiment.

[0110] Among the 492 monomer 11 / dimer 12 couples, hundred-one monomer11 / dimer 12 couples are considered stable according to the first criterion.

[0111] The hundred-one monomer 11 / dimer 12 stable couples are listed in table1. The hundred-one couples are numbered I to CI. For each of the hundred-onemonomer 11 / dimer 12 couples, the chemical structure, the family or formula, thevalence, the standard enthalpy of reaction ΔRH°298K and the standard entropy ofreaction ΔRS°298K are reported in table 1. The Simplified Molecular Input Line EntrySpecification, said SMILES, of the hundred-one couples the monomer 11 and ofthe dimer 12 are reported in table 2.Couples Chemical structure Family- number (RiXXRi) For-Valence ΔRH°298K ΔRS°298Kmula IFOOF 1 2 193.4 1.433x10-1II ClOOCl 1 2 82 1.389x10-1III BrOOBr 1 2 108.1 1.373x10-1IV FSSF 1 2 326.8 1.42x10-1V BrSSBr 1 2 267.5 1.363x10-1VI FFBBFF 2 3 439.6 1.67x10-1VII ClFBBFCl 2 3 425.8 1.67x10-1VIII BrFBBFBr 2 3 418.8 1.7x10-1IX ClClBClCl 2 3 426.4 1.59x10-1X BrClBBClBr 2 3 427.3 1.72x10-1XI BrBrBBBrBr 2 3 425.6 1.68x10-1XII FFPPFF 2 3 180.8 1.752x10-1XIII FClPPClF 2 3 192.9 1.781x10-1XIV FBrPPBrF 2 3 197 1.785x10-1XV ClClPPClCl 2 3 204.2 1.811x10-1XVI ClBrPPBrCl 2 3 208.3 1.808x10-1XVII BrBrPPBrBr 2 3 212.3 1.814x10-1XVIII FFNNFF 2 3 92.7 1.933x10-1XIX FClNNClF 2 3 119.9 1.963x10-1XX FBrNNBrF 2 3 145 1.954x10-1XXI ClClNNClCl 2 3 123.6 1.928x10-1XXII ClBrNNCrCl 2 3 143.6 1.895x10-1XXIII BrBrNNBrBr 2 3 156.1 1.871x10-1XXIV FFBrBrFF 2 3 16.8 1.731x10-1XXV ClFBrBrFCl 2 3 - 1.76x10-1XXVI OBBO 3 3 487.7 2.08x10-1XXVII SBBS 3 3 491.3 2.07x10-1XXVIII OPPO 3 3 120.5 1.054x10-1XXIX ONNO 3 3 - 1.23x10-1XXX SNNS 3 3 164.7 2.007x10-1XXXI FFONNOFF 4 3 53.7 1.929x10-1XXXII ClClONNOClCl 4 3 57.7 2.187x10-1XXXIII BrBrONNOBrBr 4 3 34 2.199x10-1XXXIV SONNOS 5 3 43.6 1.758x10-1XXXV FFFSSFFF 6 4 145.9 2.045x10-1XXXVI FFClSSClFF 6 4 136.6 2.003x10-1XXXVII FFFCCFFF 6 4 416.7 1.98x10-1XXXVIII ClFFCCFFCl 6 4 386.5 2.03x10-1XXXIX BrFFCCFFBr 6 4 381.4 2.04x10-1XL ClClFCCFClCl 6 4 351.9 2.09x10-1XLI BrBrFCCFBrBr 6 4 351.3 2.1x10-1XLII ClClClCCClClCl 6 4 312 2.16x10-1XLIII BrClClCCClClBr 6 4 312.1 2.16x10-1XLIV BrBrClCCClBrBr 6 4 311.3 2.16x10-1XLV BrBrBrCCBrBrBr 6 4 308.1 2.17x10-1XLVI FOCCOF 7 4 362,3 1.82x10-1XLVII ClOCCOCl 7 4 292,8 1.88x10-1XLVIII ClSCCSCl 7 4 320,8 1.82x10-1XLIX FSCCSF 7 4 367,4 1.85x10-1L BrSCCSBr 7 4 316,6 1.84x10-1LI BrOCCOBr 7 4 248.2 2.066x10-1LII FOSSOF 7 4 55.2 1.685x10-1LIII ClOSSOCl 7 4 54.6 1.710x10-1LIV BrOSSOBr 7 4 57.1 1.719x10-1LV NSSN 8 4 29.3 1.267x10-1LVI BCCB 8 4 813.6 1.25x10-1LVII PCCP 8 4 599.6 1.62x10-1LVIII NCCN 8 4 579.4 1.6x10-1LIX FFFFPPFFFF 9 5 270.9 1.939x10-1LX FFFClPPClFFF 9 5 267.3 1.961x10-1LXI FFFBrPPBrFFF 9 5 264.8 2.036x10-1LXII FFClClPPClClFF 9 5 262.3 1.943x10-1LXIII FFBrBrPPBrBrFF 9 5 254 1.951x10-1LXIV ClClClClPPClClClCl 9 5 114.5 2.204x10-1LXV ClClOPPOClCl 10 5 263.4 1.907x10-1LXVI BrBrOPPOBrBr 10 5 238.2 1.950x10-1LXVII FFSPPSFF 10 5 271 1.845x10-1LXVIII ClClSPPSClCl 10 5 225.5 1.962x10-1LXIX BrBrSPPSBrBr 10 5 205.2 1.976x10-1LXX FFOPPOFF 10 5 310.2 1.82x10-1LXXI PFPPFP 11 5 84.1 1.728x10-1LXXII PClPPClP 11 5 56.2 1.716x10-1LXXIII PBrPPBrP 11 5 45.8 1.707x10-1LXXIV FNPPNF 11 5 46.3 1.658x10-1LXXV ClNPPNCl 11 5 32.7 1.711x10-1LXXVI BrNPPNBr 11 5 27.5 1.700x10-1LXXVII OOPPOO 12 5 200.1 1.663x10-1LXXVIII SOPPOS 12 5 180.2 1.672x10-1LXXIX SSPPSS 12 5 167.3 1.651x10-1LXXX FFFFFSSFFFFF 13 6 195.4 2.268x10-1LXXXI ClFFFFSSFFFFC 13 6 118.3 2.339x10-1LXXXII BrFFFFSSFFFFBr 13 6 101.5 2.545x10-1LXXXIII ClClFFFSSFFFClCl 13 6 56.7 2.595x10-1LXXXIV FFFOSSOFFF 14 6 92.7 2.053x10-1LXXXV SFFFSSFFFS 14 6 80.8 1.976x10-1LXXXVI SClFFSSFFClS 14 6 72.2 2.027x10-1LXXXVII SBrFFSSFFBrS 14 6 67.6 2.027x10-1LXXXVIII ClClNSSNClCl 15 6 16.3 1.556x10-1LXXXIX FFPSSPFF 15 6 - 1.6x10-1XC FOOSSOOF 16 6 175.8 1.859x10-1XCI ClOOSSOOCl 16 6 140.7 1.891x10-1XCII BrOOSSOOBr 16 6 119.6 1.957x10-1XCIII FSOSSOSF 16 6 134.6 1.864x10-1XCIV ClSOSSOSCl 16 6 105.5 1.859x10-1XCV BrSOSSOSBr 16 6 97.2 1.832x10-1XCVI SSFSSFSS 16 6 67.5 1.779x10-1XCVII SSClSSClSS 16 6 59.4 1.735x10-1XCVIII SSBrSSBrSS 16 6 77.2 1.680x10-1XCIX SNSSNS 17 6 29.5 1.678x10-1C OOOClClOOO 20 7 40.7 1.708x10-1CI OOOBrBrOOO 20 7 - 1.52x10-1Table 1 Couples numberMonomer SMILES Dimer SMILESI [O](F) O(F)O(F)II [O](Cl) O(Cl)O(Cl)III [O](Br) O(Br)O(Br)IV [S](F) S(F)S(F)V [S](Br) S(Br)S(Br)VI [B](F)(F) B(F)(F)B(F)(F)VII [B](F)(Cl) B(F)(Cl)B(F)(Cl)VIII [B](F)(Br) B(F)(Br)B(F)(Br)IX [B](Cl)(Cl) B(Cl)(Cl)B(Cl)(Cl)X [B](Cl)(Br) B(Cl)(Br)B(Cl)(Br)XI [B](Br)(Br) B(Br)(Br)B(Br)(Br)XII [P](F)(F) P(F)(F)P(F)(F)XIII [P](F)(Cl) P(F)(Cl)P(F)(Cl)XIV [P](F)(Br) P(F)(Br)P(F)(Br)XV [P](Cl)(Cl) P(Cl)(Cl)P(Cl)(Cl)XVI [P](Cl)(Br) P(Cl)(Br)P(Cl)(Br)XVII [P](Br)(Br) P(Br)(Br)P(Br)(Br)XVIII [N](F)(F) N(F)(F)N(F)(F)XIX [N](F)(Cl) N(F)(Cl)N(F)(Cl)XX [N](F)(Br) N(F)(Br)N(F)(Br)XXI [N](Cl)(Cl) N(Cl)(Cl)N(Cl)(Cl)XXII [N](Cl)(Br) N(Cl)(Br)N(Cl)(Br)XXIII [N](Br)(Br) N(Br)(Br)N(Br)(Br)XXIV [Br](F)(F) Br(F)(F)Br(F)(F)XXV [Br](F)(Cl) Br(F)(Cl)Br(F)(Cl)XXVI [B](=O) B(=O)B(=O)XXVII [B](=S) B(=S)B(=S)XXVIII [P](=O) P(=O)P(=O)XXIX [N](=O) N(=O)N(=O)XXX [N](=S) N(=S)N(=S)XXXI [N+]([O-])(F)(F) [N+]([O-])(F)(F)[N+]([O-])(F)(F)XXXII [N+]([O-])(Cl)(Cl) [N+]([O-])(Cl)(Cl)[N+]([O-])(Cl)(Cl)XXXIII [N+]([O-])(Br)(Br) [N+]([O-])(Br)(Br)[N+]([O-])(Br)(Br)XXXIV [N+]([O-])(=S) [N+]([O-])(=S)[N+]([O-])(=S)XXXV [S](F)(F)(F) S(F)(F)(F)S(F)(F)(F)XXXVI [S](F)(F)(Cl) S(F)(F)(Cl)S(F)(F)(Cl)XXXVII [C](F)(F)(F) C(F)(F)(F)C(F)(F)(F)XXXVIII [C](F)(F)(Cl) C(F)(F)(Cl)C(F)(F)(Cl)XXXIX [C](F)(F)(Br) C(F)(F)(Br)C(F)(F)(Br)XL [C](F)(Cl)(Cl) C(F)(Cl)(Cl)C(F)(Cl)(Cl)XLI [C](F)(Br)(Br) C(F)(Br)(Br)C(F)(Br)(Br)XLII [C](Cl)(Cl)(Cl) C(Cl)(Cl)(Cl)C(Cl)(Cl)(Cl)XLIII [C](Cl)(Cl)(Br) C(Cl)(Cl)(Br)C(Cl)(Cl)(Br)XLIV [C](Cl)(Br)(Br) C(Cl)(Br)(Br)C(Cl)(Br)(Br)XLV [C](Br)(Brl)(Br) C(Br)(Br)(Br)C(Br)(Br)(Br)XLVI [C](=O)(F) C(=O)(F)C(=O)(F)XLVII [C](=O)(Cl) C(=O)(Cl)C(=O)(Cl)XLVIII [C](=S)(Cl) C(=S)(Cl)C(=S)(Cl)XLIX [C](=S)(F) C(=S)(F)C(=S)(F)L [C](=S)(Br) C(=S)(Br)C(=S)(Br)LI [C](=O)(Br) C(=O)(Br)C(=O)(Br)LII [S](=O)(F) S(=O)(F)S(=O)(F)LIII [S](=O)(Cl) S(=O)(Cl)S(=O)(Cl)LIV [S](=O)(Br) S(=O)(Br)S(=O)(Br)LV [S](#N) S(#N)S(#N)LVI [C](#B) C(#B)C(#B)LVII [C](#P) C(#P)C(#P)LVIII [C](#N) C(#N)C(#N)LIX [P](F)(F)(F)(F) P(F)(F)(F)(F)P(F)(F)(F)(F)LX [P](F)(F)(F)(Cl) P(F)(F)(F)(Cl)P(F)(F)(F)(Cl)LXI [P](F)(F)(F)(Br) P(F)(F)(F)(Br)P(F)(F)(F)(Br)LXII [P](F)(F)(Cl)(Cl) P(F)(F)(Cl)(Cl)P(F)(F)(Cl)(Cl)LXIII [P](F)(F)(Br)(Br) P(F)(F)(Br)(Br)P(F)(F)(Br)(Br)LXIV [P](Cl)(Cl)(Cl)(Cl) P(Cl)(Cl)(Cl)(Cl)P(Cl)(Cl)(Cl)(Cl)LXV [P](=O)(Cl)(Cl) P(=O)(Cl)(Cl)P(=O)(Cl)(Cl)LXVI [P](=O)(Br)(Br) P(=O)(Br)(Br)P(=O)(Br)(Br)LXVII [P](=S)(F)(F) P(=S)(F)(F)P(=S)(F)(F)LXVIII [P](=S)(Cl)(Cl) P(=S)(Cl)(Cl)P(=S)(Cl)(Cl)LXIX [P](=S)(Br)(Br) P(=S)(Br)(Br)P(=S)(Br)(Br)LXX [P](=O)(F)(F) P(=O)(F)(F)P(=O)(F)(F)LXXI [P](#P)(F) P(#P)(F)P(#P)(F)LXXII [P](#P)(Cl) P(#P)(Cl)P(#P)(Cl)LXXIII [P](#P)(Br) P(#P)(Br)P(#P)(Br)LXXIV [P](#N)(F) P(#N)(F)P(#N)(F)LXXV [P](#N)(Cl) P(#N)(Cl)P(#N)(Cl)LXXVI [P](#N)(Br) P(#N)(Br)P(#N)(Br)LXXVII [P](=O)(=O) P(=O)(=O)P(=O)(=O)LXXVIII [P](=O)(=S) P(=O)(=S)P(=O)(=S)LXXIX [P](=S)(=S) P(=S)(=S)P(=S)(=S)LXXX [S](F)(F)(F)(F)(F) S(F)(F)(F)(F)(F)S(F)(F)(F)(F)(F)LXXXI [S](F)(F)(F)(F)(Cl) S(F)(F)(F)(F)(Cl)S(F)(F)(F)(F)(Cl)LXXXII [S](F)(F)(F)(F)(Br) S(F)(F)(F)(F)(Br)S(F)(F)(F)(F)(Br)LXXXIII [S](F)(F)(F)(Cl)(Cl) S(F)(F)(F)(Cl)(Cl)S(F)(F)(F)(Cl)(Cl)LXXXIV [S](=O)(F)(F)(F) S(=O)(F)(F)(F)S(=O)(F)(F)(F)LXXXV [S](=S)(F)(F)(F) S(=S)(F)(F)(F)S(=S)(F)(F)(F)LXXXVI [S](=S)(F)(F)(Cl) S(=S)(F)(F)(Cl)S(=S)(F)(F)(Cl)LXXXVII [S](=S)(F)(F)(Br) S(=S)(F)(F)(Br)S(=S)(F)(F)(Br)LXXXVIII [S](#N)(Cl)(Cl) S(#N)(Cl)(Cl)S(#N)(Cl)(Cl)LXXXIX [S](#P)(F)(F) S(#P)(F)(F)S(#P)(F)(F)XC [S](=O)(=O)(F) S(=O)(=O)(F)S(=O)(=O)(F)XCI [S](=O)(=O)(Cl) S(=O)(=O)(Cl)S(=O)(=O)(Cl)XCII [S](=O)(=O)(Br) S(=O)(=O)(Br)S(=O)(=O)(Br)XCIII [S](=O)(=S)(F) S(=O)(=S)(F)S(=O)(=S)(F)XCIV [S](=O)(=S)(Cl) S(=O)(=S)(Cl)S(=O)(=S)(Cl)XCV [S](=O)(=S)(Br) S(=O)(=S)(Br)S(=O)(=S)(Br)XCVI [S](=S)(=S)(F) S(=S)(=S)(F)S(=S)(=S)(F)XCVII [S](=S)(=S)(Cl) S(=S)(=S)(Cl)S(=S)(=S)(Cl)XCVIII [S](=S)(=S)(Br) S(=S)(=S)(Br)S(=S)(=S)(Br)XCIX [S](#N)(=S) S(#N)(=S)S(#N)(=S)C [Cl](=O)(=O)(=O) Cl(=O)(=O)(=O)Cl(=O)(=O)(=O)CI [Br](=O)(=O)(=O) Br(=O)(=O)(=O)Br(=O)(=O)(=O)Table 2

[0112] According to a second improvement of the non-limiting embodiment, andstill for the sake of simplifying the calculations and the description of the invention,only monomer 11 / dimer 12 couples having noteworthy kinetics features (associa-tion / dissociation being sufficiently fast and reversible) are addressed.

[0113] In others words, according to the second improvement, only the monomer11 / dimer 12 couples being stable and exhibiting highly fast and reversible mono- mer 11 association / dimer 12 dissociation are considered.

[0114] To that end, according to the second improvement, a second criterion isapplied to select “highly fast and reversible association / dissociation”.

[0115] The second criterion is based on the backward constant rate (kb) (said kafor association of dimers 11 into monomers 12) and the forward or reverse con-stant rate (kf) (said kd for dissociation of monomers 12 into dimers 11). Any meas-ure / value related to, derived from or function of ka and / or kd may be used.

[0116] According to the second improvement, the dissociation time (td) and theassociation time (ta) have been considered to select the monomer 11 / dimer 12couples. The dissociation time td may be expressed as being equal to 1 / kd and theassociation time ta may be expressed as being equal to 1 / (ka.CM) where CM is theconcentration of the monomers at the considered temperature and pressure. Thesecond criterion according to the second improvement is: the dissociation time td and the association time ta are each lower than or equal to 10 milliseconds (ms).

[0117] Preferably, the second improvement is taken in combination with the firstimprovement of the non-limiting embodiment. In others words, only the monomer 11 / dimer 12 couples being stable and exhibiting noteworthy thermodynamics fea- tures are considered. Thus, the first and second criteria are applied / combined.

[0118] According to the combination of the first and the second improvements ofthe non-limiting embodiment, among the hundred-one stable couples, seventy-two monomer 11 / dimer 12 couples being stable and having noteworthy kineticsfeatures (association / dissociation being sufficiently fast and reversible) have beenselected (by applying both the first and the second criterion). The seventy-twocouples are reported in table 3. For each of the seventy-two monomer 11 / dimer12 couples, the couple number (provided in table 1), the family or formula, theforward constant rate (kd), in s-1, the backward constant rate (ka), in cm3.mol-1.s-1, the standard enthalpy of reaction ΔRH°298K and the standard entropy of reactionΔRS°298K are reported in table 3.Couples number kd ka ΔRH°298K ΔRS°298KI 7.9x105 2.7x1013 193.4 0.143II 5.2x1011 4.6x1013 82.1 0.139III 2.3x1010 5.6x1013 108.1 0.137V 1.1x102 6.3x1013 267.5 0.136XII 3.6x106 5.8x1011 180.8 0.175XIII 8.4x105 4.1x1011 192.9 0.178XIV 5.1x105 4.0x1011 197.0 0.178XV 2.2x105 2.9x1011 204.2 0.181XVI 1.3x105 3.01011 208.3 0.181XVII 8.2x104 2.8x1011 212.3 0.181XVIII 1.4x1011 6.7x1010 92.7 0.193XIX 5.4x109 4.6x1010 119.9 0.196XX 2.7x108 5.2x1010 145.0 0.195XXI 3.5x109 7.0x1010 123.7 0.193XXII 3.2x108 1.0x1011 143.6 0.190XXIII 7.0x107 1.4x1011 156.1 0.187XXIV 1.3x1015 7.5x1011 16.8 0.173XXV 1.6 x1016 5.5x1011 -3.7 0.176XXVIII 5.1x109 2.6x1015 120.5 0.105XXIX 1.0x1017 3.3x1014 -19.3 0.123XXX 2.5x107 2.7x1010 164.7 0.201XXXI 1.6x1013 7.0x1010 53.7 0.193XXXII 9.7x1012 3.1x109 57.7 0.219XXXIII 1.7x1014 2.7x109 34.0 0.220XXXIV 5.3x1013 5.5x1011 43.6 0.176XXXV 2.4x108 1.7x1010 145.9 0.204XXXVI 7.3x108 2.9x1010 136.7 0.200LI 1.1x103 1.3x1010 248.2 0.207LII 1.3x1013 1.3x1012 55.2 0.169LIII 1.4x1013 9.7x1011 54.6 0.171LIV 1.0x1013 8.8x1011 57.1 0.172LV 2.9x1014 2.0x1014 29.3 0.127LX 1.1x102 4.7x1010 267.3 0.196LXI 1.5x102 1.9x1010 264.8 0.204LXII 2.0x102 5.9x1010 262.3 0.194LXIII 5.4x102 5.3x1010 254.0 0.195LXIV 1.0x1010 2.5x109 114.5 0.220LXV 1.7x102 9.0x1010 263.4 0.191LXVI 3.6x103 5.4x1010 238.2 0.195LXVIII 1.7x104 4.7x1010 225.5 0.196LXIX 1.9x105 3.9x1010 205.2 0.198LXXI 4.0x1011 7.8x1011 84.1 0.173LXXII 1.2x1013 9.1x1011 56.2 0.172LXXIII 4.0x1013 1.0x1012 45.8 0.171LXXIV 3.8x1013 1.8x1012 46.4 0.166LXXV 1.9x1014 9.5x1011 32.7 0.171LXXVI 3.7x1014 1.1x1012 27.5 0.170LXXVII 3.5x105 1.7x1012 200.1 0.166LXXVIII 3.9x106 1.5x1012 180.2 0.167LXXIX 1.8x107 2.0x1012 167.3 0.165LXXX 6.2x105 1.2x109 195.4 0.227LXXXI 6.6x109 5.0x108 118.3 0.234LXXXII 5.0x1010 4.2x107 101.5 0.254LXXXIII 1.1x1013 2.3x107 56.7 0.260LXXXIV 1.4x1011 1.6x1010 92.7 0.205LXXXV 6.0x1011 4.0x1010 80.8 0.198LXXXVI 1.7x1012 2.2x1010 72.2 0.203LXXXVII 2.9x1012 2.2x1010 67.6 0.203LXXXVIII 1.4x1015 6.2x1012 16.3 0.156LXXXIX 4.5x1016 3.6x1012 -12.5 0.160XC 6.6x106 1.6x1011 175.8 0.186XCI 4.5x108 1.1x1011 140.7 0.189XCII 5.7x109 5.0x1010 119.6 0.196XCIII 9.3x108 1.5x1011 134.6 0.186XCIV 3.1x1010 1.6x1011 105.5 0.186XCV 8.3x1010 2.2x1011 97.3 0.183XCVI 3.0x1012 4.2x1011 67.5 0.178XCVII 7.9x1012 7.2x1011 59.4 0.174XCVIII 9.2x1011 1.4x1012 77.3 0.168XCIX 2.9x1014 1.4x1012 29.5 0.168C 7.4x1013 1.0x1012 40.7 0.171CI 4.7x1017 9.9x1012 -31.9 0.152Table 3

[0119] According to a third improvement of the non-limiting embodiment, and stillfor the sake of simplifying the calculations and the description of the invention, only monomer 11 / dimer 12 couples having noteworthy kinetics features (associa- tion / dissociation being sufficiently fast and reversible) are addressed.

[0120] Preferably, but not necessarily, the third improvement may be consideredas an alternative to the second improvement.

[0121] In others words, according to the third improvement, only the monomer11 / dimer 12 couples exhibiting highly fast and reversible monomer 11 associa- tion / dimer 12 dissociation are considered.

[0122] To that end, according to a third improvement, a third criterion is appliedto select “highly fast and reversible association / dissociation”.

[0123] The third criterion is: a reaction (that is the monomer 11 / dimer 12 associ-ation / dissociation) relaxation time, τ, lower than or equal to 0.1 ms. The monomer11 and / or the dimer 12 having a relaxation time τ according to the third criterion are considered to exhibit fast association and dissociation during the phases of a thermodynamic cycle.

[0124] The relaxation time is function of and / or is calculated from the forwardconstant rate (kd) and the backward constant rate (ka).

[0125] The equilibrium constant, Keq, may be expressed: Keq(T) = kd / ka.

[0126] As non-limiting example, for the dissociation reaction, Ri-X-X-Ri ^ 2(Ri-X•),the activation energy can be assumed to be equal to the standard enthalpy of reaction of the system. As non-limiting embodiment, the rate constant of the dis- sociation reaction (kd) can be calculated with the Arrhenius law, considering a pre-exponential factor being equal, for example, to 1.1016 s-1. The association (back-ward) rate constant (ka) (in cm3.mol-1.s-1) can be calculated from the equilibrium constant (Keq) and the dissociation rate constant, kd. From ka and kd, the relaxation time, τ (in s), of the reaction can be determined and then compared to the resi- dential time of the fluid in the operation units of the considered thermodynamic conversion machine.

[0127] The standard enthalpy of reaction (ΔRH°298K) (in kJ / mol) and the standardentropy of reaction (ΔRS°298K) (in kJ / mol / K) associated with the association / disso- ciation of each monomer 11 / dimer 12 couple enable the calculation of the equilib- rium constant of the reaction (which is also function of temperature).

[0128] The entropy of reaction (ΔRS°298K) (in kJ / mol / K) associated with the asso-ciation / dissociation of each monomer 11 / dimer 12 couple may be related to the enthalpy of reaction (ΔRH°298K) through the standard Gibbs energy of reaction (ΔRG°298K) (in kJ / mol).

[0129] Preferably, the third improvement is taken in combination with the firstimprovement of the non-limiting embodiment. In others words, only the monomer 11 / dimer 12 couples being stable and exhibiting noteworthy kinetics features areconsidered. Thus, the first and third criteria are applied / combined.

[0130] According to the combination of the first and the third improvements of thenon-limiting embodiment among the hundred-one stable couples, seventy-sixmonomer 11 / dimer 12 couples being stable and having noteworthy kinetics fea- tures (association / dissociation being sufficiently fast and reversible) have beenselected (by applying both the first and the third criterion). The seventy-six cou-ples are reported in table 4. For each of the seventy-six monomer 11 / dimer 12couples, the couple number (provided in table 1), and the monomer 11 / dimer 12 association / dissociation relaxation time, τ, in seconds, are reported in table 4. Couples number Relaxation time τ (in sec- onds) I1.6x10-8II 1.9x10-12III 4.0x10-11IV 4.4x10-5V 8.8x10-7XII 5.6x10-8XIII 1.3x10-7XIV 1.7x10-7XV 3.1x10-7XVI 3.8x10-7XVII 5.0x10-7XVIII 6.9x10-12XIX 1.8x10-10XX 3.7x10-9XXI 2.9x10-10XXII 3.1x10-9XXIII 1.3x10-8XXIV 7.6x10-16XXV 6.4x10-17XXVIII 2.2x10-11XXIX 9.8x10-18XXX 3.8x10-8XXXI 6.4x10-14XXXII 1.0x10-13XXXIII 6.0x10-15XXXIV 1.9x10-14XXXV 4.2x10-9XXXVI 1.4x10-9XLVII 8.9x10-5LI 1.9x10-5LII 7.7x10-14LIII 7.1x10-14LIV 9.6x10-14LV 3.4x10-15LIX 3.5x10-5LX 3.2x10-5LXI 4.3x10-5LXII 2.1x10-5LXIII 1.4x10-5LXIV 9.6x10-11LXV 1.8x10-5LXVI 5.3x10-6LXVII 2.0x10-5LXVIII 2.7x10-6LXIX 9.3x10-7LXXI 2.5x10-12LXXII 8.6x10-14LXXIII 2.5x10-14LXXIV 2.6x10-14LXXV 5.1x10-15LXXVI 2.7x10-15LXXVII 9.5x10-8LXXVIII 3.2x10-8LXXIX 1.4x10-8LXXX 1.5x10-6LXXXI 1.5x10-10LXXXII 2.0x10-11LXXXIII 9.1x10-14LXXXIV 6.9x10-12LXXXV 1.7x10-12LXXXVI 5.9x10-13LXXXVII 3.4x10-13LXXXVIII 7.1x10-16LXXXIX 2.2x10-17XC 7.8x10-8XCI 2.2x10-9XCII 1.8x10-10XCIII 1.1x10-9XCIV 3.2x10-11XCV 1.2x10-11XCVI 3.4x10-13XCVII 1.3x10-13XCVIII 1.1x10-12XCIX 3.5x10-15C 1.3x10-14CI 2.2x10-18Table 4

[0131] According to a fourth improvement of the non-limiting embodiment, andstill for the sake of simplifying the calculations and the description of the invention, only monomer 11 / dimer 12 couples having noteworthy thermodynamics features (the monomers 11 / dimers 12 composition changes, in the considered temperatureand pressure ranges of the application, in a sufficient amount so that the energyinvolved / associated in the change is significant) are addressed.

[0132] In other words, according to the fourth improvement, only the monomer11 / dimer 12 couples exhibiting “sufficiently high variation of monomers 11 / dimers12 composition” are considered.

[0133] To that end, according to the fourth improvement, a fourth criterion is ap-plied to select “sufficiently high variation of monomers 11 / dimers 12 composition”.

[0134] The fourth criterion is based on the variation of the molar fraction molarfraction, said xM, of the monomers 11 and / or on the variation of the molar fraction,said xD, of the dimers 12 of the couples. Preferably, the fourth criterion is basedon the variation of: the absolute value of the molar fraction xM of the monomers11 and / or the absolute value of the molar fraction xD of the dimers 12 of thecouples. The fourth criterion is: the variation of the molar fraction xM of the mon-omers 11 and / or variation of the molar fraction xD of the dimers 12 is higher than or equal to 0.3.

[0135] The molar fraction is comprised between 0 and 1. The molar fraction xM ofthe monomers 11 may increase with the temperature. The molar fraction xD of the dimers 12 may decrease with the temperature. The monomer 11 and / or the dimer12 having a variation of the molar fraction xD, xM according to the fourth criterionare considered to highly evolve (in quantity: molar concentration or volume…) from monomers 11 to dimers 12, through association, and from dimers 12 to mon- omers 11, through dissociation (i.e. the couple has a sufficient change in compo- sition of the mixture monomer 11 / dimer 12), during the phases of a thermody- namic cycle.

[0136] The equilibrium constant enables the determination of the composition ofthe reactive mixture at a given temperature, that is the molar fraction xM of the monomer 11 and the complementary molar fraction xD of the dimer 12.

[0137] Preferably, the fourth improvement is taken in combination with the firstimprovement of the non-limiting embodiment. In others words, only the monomer11 / dimer 12 couples being stable and exhibiting noteworthy thermodynamics fea- tures are considered. Thus, the first and fourth criteria are applied / combined.

[0138] According to the combination of the first and the fourth improvement ofthe non-limiting embodiment, among the hundred-one stable couples, forty-onemonomer 11 / dimer 12 couples satisfy the third criterion (i.e. the first and fourthcriteria). The forty-one monomer 11 / dimer 12 couples being stable and having“sufficiently high variation of monomers 11 / dimers 12 composition” are listed intable 5. For each of the forty-one monomer 11 / dimer 12 couples, the couple num-ber (provided in table 1) and the variation of the absolute value of the molar frac- tion xM of the monomers 11 are reported in table 5. Couples number xM variationII 0.9988III 0.9717XII 0.5036XIII 0.3354XVIII 0.9997XIX 0.9999XX 0.9977XXI 0.9998XXII 0.9961XXIII 0.9769XXVIII 0.3310XXX 0.9871XXXI 0.3183XXXV 0.9991XXXVI 0.9995LII 0.8171LIII 0.7655LIV 0.8483LXIV 1.0000LXIX 0.4642LXXI 0.9994LXXII 0.8207LXXIV 0.3411LXXVIII 0.3648LXXIX 0.5726LXXX 0.9779LXXXI 1.0000LXXXII 0.9981LXXXIV 0.9994LXXXV 0.9950LXXXVI 0.9581LXXXVII 0.8926XC 0.8067XCI 0.9970XCII 0.9999XCIII 0.9980XCIV 0.9999XCV 0.9999XCVI 0.9744XCVII 0.8937XCVIII 0.9982Table 5

[0139] All the calculations (ka, kd, τ, xM variation, ΔRS°298K, ΔRH°298K) and the chem-ical structure of the monomer 11 / dimer 12 couples have been simulated through a Fortran code specially developed to design these reactions.

[0140] The calculations of the thermochemical properties (ΔRH° and ΔRG°) havebeen made at 298.15 Kelvins (K).

[0141] The kinetic constants (ka, kd) and the derived relaxation time τ are calcu-lated at 1000 K.

[0142] The design of the chemical structure of the monomer 11 / dimer 12 coupleshas been performed with a Fortran code specifically developed to this purpose.

[0143] The stability analysis and the calculation of the thermochemical properties(ΔRH°298K and ΔRG°298K), at the basis of kinetics and thermodynamic calculations (xM, xD variation), have been performed with Gaussian09.

[0144] According to the detailed embodiment, the reactive working fluid 10 maycomprise any of the monomer 11 / dimer 12 couple(s) described and listed above.

[0145] The improvements may be considered independently from one another. Inother word, only one of the criterion may be applied. Thus, the monomer 11 / dimer12 couple(s) may be selected from any of the improvements.

[0146] The improvements may be considered in combination.

[0147] One considered improvement may be taken in combination with one, sev-eral or all of the other improvements. In other word, the monomer 11 / dimer 12 couple(s) may be selected according to two or more of the criteria.

[0148] As an illustrative example of combination, the first, third and fourth im-provements are considered in combination. According to this combination forty-one monomer 11 / dimer 12 couples meet the first, third and fourth criteria. Thecouple number (provided in table 1) of the forty-one monomer 11 / dimer 12 cou- ples satisfying the first, third and fourth criteria are reported in table 6.

[0149] One can see that the monomer 11 / dimer 12 couples selected through thecombination of the first, third and fourth improvements are the same as the mon- omer 11 / dimer 12 couples selected by applying the fourth criterion alone. This is due to the high limitation provided by the fourth criterion. Couples numberII III XII XIII XVIII XIX XX XXI XXII XXIII XXVIII XXX XXXI XXXV XXXVI LII LIII LIV LXIV LXIX LXXI LXXII LXXIV LXXVIII LXXIX LXXX LXXXI LXXXII LXXXIVLXXXV LXXXVI LXXXVII XC XCI XCII XCIII XCIV XCV XCVI XCVII XCVIII Table 6

[0150] Regarding the non-limiting embodiments, the choice of the criterion / crite-ria to be applied is, preferably, made according to one considered thermodynamicconversion machine (i.e. according to a specific application). Thus, the criteria,preferably the value(s) of the criteria / criterion, may be adapted according to aconsidered conversion machine or a type of conversion machine and / or accordingto the specific working parameters of the considered conversion machine or thetype of conversion machine.

[0151] Still regarding the non-limiting embodiments, it may be highlighted thatthe couples (i.e. the number of couples identified) satisfying the criterion / criteriadepend on the temperature (i.e. the specific working parameters of one consideredconversion machine) at which the calculations are made.

[0152] Preferably, the operating range considered in the non-limiting embodimentare comprised between 253 and 1000 K and 0.01 and 300 bars. As non-limitingexamples the operating range are comprised between:- 283 K et 1000 K and between 0.01 and 300 bars in power plants,- 253 K and 500 K and 0.01 and 100 bars in heat pumps,- 253 K and 353 K and 0.01 and 100 bars for refrigeration applications.

[0153] Due to the temperature used for the calculations of the kinetic constants(ka, kd) and the relaxation time τ, the monomer 11 / dimers 12 couples accordingto the improvements are particularly, but not exclusively, suitable for power plantsapplications (that is temperature comprised between 283 and 1000 K).

[0154] As illustrating and non-limiting examples, the monomer 11 / dimer 12 cou-ples according to the non-limiting embodiment selected by the combination of thefirst, third and fourth improvements for power plants applications (1000 K), heatpumps applications (500 K) and refrigeration applications (353 K) are listed in table 7. Power plant applications Heat pump applications refrigeration applicationsII XVIII XXXIIII XXXI XXXIIXII XXXII XXXIVXIII XXXIV LIIXVIII LII LIIIXIX LIII LIVXX LIV LXXIIXXI LXIV LXXIIIXXII LXXI LXXIVXXIII LXXII LXXXVIXXVIII LXXIII LXXXVIIXXX LXXIV XCVIXXXI LXXXI XCVIIXXXV LXXXIIXXXVI LXXXIVLII LXXXVLIII LXXXVILIV LXXXVIILXIV XCVLXIX XCVILXXI XCVIILXXII XCVIIILXXIV LXXVIII LXXIXLXXX LXXXI LXXXII LXXXIV LXXXV LXXXVI LXXXVII XC XCI XCII XCIII XCIV XCV XCVI Table 7

[0155] Preferably, but not necessarily, the working fluid 10 according to the in-vention comprises monomer 11 / dimer 12 couples having a relaxation time τ lowerthan or equal to preferably to 0.6 second (s), more preferably to 0.5, most pref-erably to 0.4, even most preferably to 0.3, particularly advantageously to 0.2, particularly advantageously to 0.1, more particularly advantageously to 0.01, evenmore particularly advantageously to 0.01, in a particularly advantageous mannerto 0.001 and in the most preferred manner to 0.0001 s.

[0156] Preferably, but not necessarily, the working fluid 10 according to the in-vention comprises monomer 11 / dimer 12 couples having a (ka) constant higher than or equal to 1x105cm3.mol-1.s-1, preferably to 1x106, more preferably to 1x107, most preferably to 1x108, even most preferably to 1x109, particularly advanta- geously to 1x109, particularly advantageously to1x1010, more particularly advan-tageously to 1x1011, even more particularly advantageously to 1x1012, in a partic-ularly advantageous manner to 1x1013and in the most preferred manner to 2x1013cm3.mol-1.s-1.

[0157] Monomer 11 / dimer 12 couples having a (ka) as listed in the previous par-agraph may advantageously contribute to increase the dissociation of dimer 12 into monomer 12.

[0158] Preferably, but not necessarily, the working fluid 10 according to the in-vention comprises monomer 11 / dimer 12 couples having a (kd) constant higher than or equal to 1x102s-1, preferably to 1x103, more preferably to 1x104, even more preferably to 1x105, most preferably to 1x106, even most preferably to 1x107, particularly advantageously to 1x108, particularly advantageously to1x109, more particularly advantageously to 1x1010, even more particularly advanta- geously to 1x1011, in a particularly advantageous manner to 1x1012and in the most preferred manner to 1x1013s-1.

[0159] Monomer 11 / dimer 12 couples having a (kd) as listed in the previous par-agraph may advantageously contribute to increase the dissociation of dimer 12into monomer 12.

[0160] Preferably, but not necessarily, the working fluid 10 according to the in-vention comprises monomer 11 / dimer 12 couples having an enthalpy of reaction(ΔRH°298K) lower than or equal to 300 kJ / mol, preferably to 250, more preferablyto 200, most preferably to 160, even most preferably to 140, particularly advan-tageously to 120, particularly advantageously to 105, more particularly advanta-geously to 95, even more particularly advantageously to 75, in a particularly ad-vantageous manner to 60 and in the most preferred manner to 55 kJ / mol.

[0161] Monomer 11 / dimer 12 couples having an enthalpy of reaction (ΔH) as listedin the previous paragraph may advantageously contribute to increase the revers- ibility of the association / dissociation of the monomers 11 / dimers 12.

[0162] Preferably, the working fluid 10 according to the invention comprises mon-omer 11 / dimer 12 couples having an electronegativity difference between X and at least one of the Ri (one of the substituent) higher than or equal to 0.3, preferably to 0.34, more preferably to, most preferably to, even most preferably to 0.38, particularly advantageously to 0.42, particularly advantageously to 0.48, moreparticularly advantageously to 0.52, even more particularly advantageously to0.56, in a particularly advantageous manner to 0.6 and in the most preferredmanner to 0.64.

[0163] The electronegativity difference between X and at least one of the Ri mayadvantageously contribute to increase (kd) constant and / or to reduce the relaxa-tion time τ and / or to increase the variation of the molar fraction xM of the mono-mers 11 and / or the molar fraction xD of the dimers 12.

[0164] Preferably, the working fluid 10 according to the invention comprises mon-omer 11 / dimer 12 couples having an electronegativity difference between one Ri(one of the substituent)and at least one other of the Ri (at least one of the sub-stituent) higher than or equal to 0.2, preferably to 0.25, more preferably to, most preferably to, even most preferably to 0.3, particularly advantageously to 0.35, particularly advantageously to 0.4, more particularly advantageously to 0.45, even more particularly advantageously to 0.5, in a particularly advantageous manner to0.55 and in the most preferred manner to 0.6.

[0165] The electronegativity difference between one Ri and at least one other ofthe Ri may advantageously contribute to increase the stability of the monomer 11.

[0166] As already described in further details, the choice of the working fluid 10,and in particular of the monomer 11 / dimer 12 couple, is advantageously doneaccording to the operating mode of the thermodynamic machine. For instance,some of the monomer 11 / dimer 12 couples having moderately satisfactory kineticand / or thermodynamic features may be mixed with a part of additives (30 or less,20 less, 10% or less, or 5% or less, in mass percentage).

[0167] According to the invention, it is also provided the use of the working fluid10 according to the invention in a thermodynamic machine 1 operating in cooling mode, a refrigeration machine for instance. The working fluid 10 or the compound 12 after the compression phase of the cycle is completely, or at least mostly, in monomers 12 form.

[0168] During the cooling phase of the thermodynamic cycle, the working fluid 10or the compound 12 or the monomers 12 undergoes a partial association into di- mers 11, that is only a part of the compound 12 or the monomers 12 undergoes an association into dimers 11. After the cooling phase, the working fluid 10 pref- erably comprises dimers 11 and monomers 12. During the cooling phase, (that is the cooling of the working fluid 10 or the heating of the environment), the working fluid 10 undergoes an exothermic reaction due to the association of a part of the monomers 12 into dimers 11. Thus, the efficiency of the energy conversion during the thermodynamic cycle is further increased.

[0169] During the expansion phase of the thermodynamic cycle, the working fluid10 or the compound 12 may undergo a further association of the entire remaining monomers 12 into dimers 11. After the expansion phase, the working fluid 10comprises mainly, preferably only, dimers 11. Indeed, it is beneficial to have acomplete association of the remaining monomers 12 into dimers 11 during the expansion phase. This allows the working fluid 10 to be only in its dimer form afterthe expansion phase and thus, to make the most of the endothermic reaction thatwill happened during the following heating phase (the description of the heating isgiven in the next paragraph). Thus, the efficiency of the energy conversion duringthe thermodynamic cycle is further increased.

[0170] During the heating phase of the thermodynamic cycle, two alternativesmay be beneficial depending on the particular case in point (for instance depending on the place of use (climate, outside temperature…), typology of the thermody- namic machine used, the specific working fluid 10 used…).

[0171] In a first alternative, the working fluid 10 or the dimers 11 undergoes acomplete dissociation into monomers 12, or at least most of the dimers 11 under- goes a dissociation into monomers 12. After the heating phase, the working fluid 10 comprises only monomers 12, or comprises mostly monomers 12 and some dimers 11 in a lower extent. During the heating phase, the reactive working fluid 10 according to the invention allows to increase the heat quantity absorbed or collected from the environment, which is the useful effect. Indeed, during the heating phase (that is the heating of the working fluid 10 and the cooling of the environment), the working fluid 10 undergoes an endothermic reaction due to the dissociation of, most of, preferably the whole of, the dimers 11 into monomers 12. Thus, the efficiency of the energy conversion during the thermodynamic cycle isfurther increased. In the first alternative, since the working fluid 10 comprises only dimers 11, or comprises mostly monomers 12 and some dimers 11 in a lower extend, after the heating phase, it is not possible to benefit from the endothermic reaction during the following compression phase anymore.

[0172] In a second alternative, the working fluid 10 or the dimers 11 undergoes apartial dissociation into monomers 12, or only some of the dimers 11 undergoes a dissociation into monomers 12. After the heating phase, the working fluid 10 com- prises monomers 12 and dimers 11. As for the first alternative, in the secondalternative, the reactive working fluid 10 according to the invention still allows toincrease the heat quantity absorbed or collected from the environment but in alower extent compare to the first alternative (due to a lower amount of dimers 11dissociated during the heating phase compare to the first alternative). Neverthe- less, the efficiency of the energy conversion during the heating phase is still in-creased compared to the working fluids of the state of the art. In the second al-ternative, since the working fluid 10 comprises monomers 12 and dimers 11 after the heating phase, the benefit from the endothermic reaction during the following compression phase (due to the presence of a significant amount of dimers 11 in the working fluid 10 during the compression phase) is used.

[0173] According to the invention, it is also provided the use of the working fluid10 according to the invention in a thermodynamic machine 1 operating in power mode, a power plant for instance. The working fluid 10 or the compound 12 afterthe compression phase of the cycle is completely, or at least mostly, in monomers12 form.

[0174] During the cooling phase of the thermodynamic cycle, the working fluid 10or the compound 12 or the monomers 12 undergo a partial association into dimers 11, that is only a part of the compound 12 or the monomers 12 undergo an asso- ciation into dimers 11. After the cooling phase, the working fluid 10 preferably comprises dimers 11 and monomers 12. During the cooling phase, (that is the cooling of the working fluid 10 or the heating of the environment), the working fluid 10 undergoes an exothermic reaction due to the association of a part of mon- omers 12 into dimers 11. Thus, the efficiency of the energy conversion during the thermodynamic cycle is further increased.

[0175] During the expansion phase of the thermodynamic cycle, the working fluid10 or the compound 12 or the monomers 12 undergoes a complete association into dimers 11, or at least most of the compound 12 or the monomers 12 under- goes an association into dimers 11. After the expansion phase, the working fluid 10 preferably comprises only dimers 11, or comprises mostly dimers 11 and mon- omers 12 in a lower extent. During the expansion phase, according to the embod-iment, the reactive working fluid 10 according to the invention allows to increasethe work quantity extracted from the working fluid 10 or released in the environ- ment (the mechanical work extracted by turbines for instance), which is the useful effect. Indeed, during the expansion phase (that is the expansion of the working fluid 10 or the mechanical work transfer to the environment), the working fluid 10 undergoes an exothermic reaction due to the association of, most of, preferably the whole of, the monomers 12 into dimers 11. Thus, the efficiency of the energy conversion during the thermodynamic cycle is further increased.

[0176] During the heating phase of the thermodynamic cycle, the working fluid 10or the compound 12 or dimers 11 undergo a dissociation into monomers 12. After the heating phase, the working fluid 10 comprises monomers 12 and dimers 11.Indeed, during the heating phase (that is the heating of the working fluid 10 orthe cooling of the environment), the working fluid 10 undergoes an endothermic reaction due to the dissociation of only a part of the dimers 11 into monomers 12. Thus, the efficiency of the energy conversion during the thermodynamic cycle is further increased.

[0177] It is also provided a cyclic thermodynamic conversion machine which com-prises the reactive working fluid 10 according to the invention.

[0178] The cyclic thermodynamic conversion machine further comprises means forcompressing a working fluid 10, means arranged to cool down the working fluid 10, means arranged for working fluid 10 expansion and means arranged to heat up the working fluid. The cyclic thermodynamic conversion machine is arranged to: -dissociate, partly only or at least partly or in its entirety, the working fluid10 into monomers 12 within the means for compressing the working fluid 10,- associate, partly only or at least partly or in its entirety the working fluid 10into dimers 11 within the means arranged to cool down the working fluid 10, -associate, partly only or at least partly or in its entirety the working fluid 10into dimers 11 within the means arranged to expand the working fluid 10, -dissociate, partly only or at least partly or in its entirety the working fluid10 into monomers 12 within the means arranged to heat up the workingfluid 10.

[0179] Preferably, the component of the cooling heat exchanger and / or of theheating heat exchanger, in which the working fluid 10 circulates, or is intended to circulate, is a heat exchanger.

[0180] The heating heat exchanger is arranged to carry out the heating phaseaccording to the invention and the cooling heat exchanger is arranged to carry out the cooling phase according to the invention. The above description relating to the heating phase and the cooling phase applies mutatis mutandis for the heating heat exchanger and the cooling heat exchanger.

[0181] The heating heat exchanger may be an evaporator and the cooling heatexchanger may be a condenser.

[0182] Preferably, the cyclic thermodynamic conversion machine comprises flowmeans for the working fluid though the components (means for compressing the working fluid, means arranged to cool down the working fluid, means arranged toexpand the working fluid and means arranged to heat up the working fluid) of thecyclic thermodynamic conversion machine.

[0183] Within the means for cooling the working fluid 10, the reactive workingfluid 10 according to the invention will increase the heat quantity released to the environment, which is the useful effect. Indeed, during the cooling phase (that is the cooling of the working fluid 10 or the heating of the environment), the working fluid 10 undergoes an exothermic reaction due to the association of, at least a part or a part only or the entirety of, the monomers 12 into dimers 11. Thus, the effi- ciency of the energy conversion during the thermodynamic cycle is further in- creased.

[0184] Within the heating heat exchanger, the reactive working fluid 10 accordingto the invention allows to increase the heat quantity absorbed or collected from the environment, which is the useful effect. Indeed, during the heating phase (that is the heating of the working fluid 10 or the cooling of the environment), the work- ing fluid 10 undergoes an endothermic reaction due to the dissociation of, at least a part or a part only or the entirety of, the dimers 11 into monomers 12. Thus, the efficiency of the energy conversion during the thermodynamic cycle is further in- creased.

[0185] Within the means arranged for working fluid 10 expansion, the reactiveworking fluid according to the invention allows to increase the work quantity ex- tracted from the working fluid 10 or the mechanical work extracted by turbines, which is the useful effect. Indeed, during the expansion phase (that is the expan- sion of the working fluid 10 or the mechanical work transfer to the environment), the working fluid 10 undergoes an exothermic reaction due to the association of,at least a part or a part only or the entirety of, the monomers 12 into dimers 11.Thus, the efficiency of the energy conversion during the thermodynamic cycle is further increased.

[0186] Within the means for compressing the working fluid 10, the reactive work-ing fluid 10 according to the invention allows to decrease the quantity of energy required for the compression of the fluid (that is the energy required to carry out the thermodynamic cycle). Indeed, during the compression of a reactive working fluid 10 according to the invention, the working fluid 10 undergoes an endothermic reaction due to the dissociation of, at least a part or a part only or the entirety of, the dimers 11 into monomers 12. The compression of a fluid increases the pressure of the fluid, which tends (thermodynamic effect) to increase its temperature. The effect of increasing the temperature, predominant with respect to the opposite effect of increasing pressure, enables the endothermic reaction to take place dur- ing the compression phase that tends to maintain the working fluid 10 colder than in case of using inert working fluids. Thus, since the compression of a colder fluid requires less energy than a hot fluid, the efficiency of the energy conversion during the thermodynamic cycle is further increased.

[0187] To illustrate the use of the reactive working fluid 10 according to the in-vention in a cyclic thermodynamic conversion machine, it is also described, as a non-limiting embodiment, a heat pump 1 comprising such reactive working fluid 10.

[0188] Regarding the heat pumps, there may exhibit several operating modes.The most common typology, which is the sole used in the domestic domain, is the “vapor compression” heat pump 1 which is illustrated FIGURE 1. In this technol- ogy, the working fluid changes according to a thermodynamic cycle comprising four thermodynamic transformations or phases comprising: -absorbing thermal energy in the heater 5, through vaporization or gaseousheating of the working fluid, which is supplied by the external environment while cooling the external environment, -compressing the working fluid in the compressor 2, while the working fluidremains in the gas phase, which increases the pressure of the working fluid to its maximum value and, consequently, increases the temperature of the working fluid to its minimum value of the thermodynamic cycle, -transferring the thermal energy of the working fluid to the external environ-ment while heating the external environment, by cooling down the working fluid in the condenser 3, -reducing the pressure of the working fluid in the expansion valve 4 whichreduces the pressure of the working fluid to its minimum value and, conse- quently, decreases the temperature of the working fluid to its minimum value of the thermodynamic cycle.

[0189] The heat pump 1 according to the embodiment comprises the reactiveworking fluid 10 according to the invention. The heat pump 1 further comprises means 2 for compressing the reactive working fluid 10. The means for compressing 2 the working fluid may be a compressor 2 or any equivalent means. The heat pump 1 further comprises means 3 arranged to condensate the reactive working fluid 10. The means to condensate 2 the working fluid may be a condenser 2 or any equivalent means. The heat pump 1 further comprises means 4 arranged to expand the reactive working fluid 10. The means to expand 4 the working fluid 10 may be an expansion valve 4 or any equivalent means. The heat pump 1 furthercomprises means 5 arranged to evaporate the working fluid 10. The means to evaporate 5 the working fluid 10 may be an evaporator 5 or any equivalent means.

[0190] Preferably, the heat pump 1 is arranged so that:- the means 2 for compressing the working fluid 10 dissociate, at least partlybut preferably in its entirety, the working fluid 10 or the dimers 11 into monomers 12, -the means 3 arranged to cool the working fluid 10 associate, at least partlybut preferably in its entirety, the working fluid 10 or the monomers 12 into dimers 11, -the means 4 arranged to expand the working fluid 10 may associate, butnot necessarily, only a part of the working fluid 10 or the monomers 12 into dimers 11, -the means 5 arranged to heat the working fluid 10 dissociate, at least partly,preferably partly only, the working fluid 10 or the dimers 11 into monomers 12.

[0191] The skilled person has the general knowledge to transpose the specific de-scription of the heat pump 1 and of the use of the working fluid 10 in a heat pump 1 according to the non-limiting embodiments to any cyclic thermodynamic conver- sion machine. The technical effects provided by the reactive working fluid 10 ac- cording to the invention, in particular those resulting from reversibly associa- tion / dissociation of the reactive working fluid 10 to form dimer / monomer respec- tively, will benefit and apply to any cyclic thermodynamic conversion machine.

[0192] Thus, any feature of the working fluid 10 made in the present documentcan be directly transposed or included in the cyclic thermodynamic conversion ma- chine(s) according to the invention and conversely.

[0193] Hence, it is also provided a cyclic thermodynamic conversion machine op-erating in refrigeration mode, said refrigeration machine, comprising the reactive working fluid 10 according to the invention.

[0194] In particular, it is provided a refrigeration machine comprising the reactiveworking fluid 10 according to the invention.

[0195] Preferably, the refrigeration machine is arranged so that:- the means for compressing the working fluid 10 dissociate, at least partlybut preferably in its entirety, the working fluid 10 or the dimers 11 into monomers 12, -the means arranged to cool the working fluid 10 associate, at least partlyand preferably partly only, the working fluid 10 or the monomers 12 into dimers 11, -the means arranged to expand the working fluid 10 associate, at least partlybut preferably in its entirety of the working fluid 10 or the monomers 12into dimers 11, -the means arranged to heat the working fluid 10 dissociate, at least partly,partly only or in its entirety, the working fluid 10 or the dimers 11 into monomers 12.

[0196] Hence, it is also provided a cyclic thermodynamic conversion machine op-erating in power mode, said power machine, comprising the reactive working fluid 10 according to the invention.

[0197] In particular, it is provided a power plant comprising the reactive workingfluid 10 according to the invention.

[0198] Preferably, the power machine or the power plant is arranged so that:- the means 2 for compressing the working fluid 10 dissociate, at least partlybut preferably in its entirety, the working fluid 10 or the dimers 11 into monomers 12, -the means arranged to cool the working fluid 10 associate, at least partlyand preferably partly only, the working fluid 10 or the monomers 12 into dimers 11, -the means arranged to expand the working fluid 10 associate, at least partlybut preferably in its entirety, the working fluid 10 or the monomers 12 into dimers 11,- the means arranged to heat the working fluid 10 dissociate, at least partlyand preferably partly only, the working fluid 10 or the dimers 11 into mon- omers 12.

[0199] The use of the reactive working fluid 10 in a heat pump 1, or a heat pump1 comprising the reactive working fluid 10, will provide an increase by 100% of the coefficient of performance (COP) defined as the ratio between the quantity of heat supplied externally (to the environment, through the heat exchanger cooling down the working fluid), which is the useful effect, and the electrical / mechanical energy required to fluid compression (the price to pay). The COP thus results to be doubled with respect to the heat pump of the state of the art. The COP currently achieved by residential heat pumps of the state of the art reaches a maximum of 4 while the COP of the heat pump 1 according to the state of the art reaches 8.

[0200] In another example, the use of the reactive working fluid 10 in a powerplant, or a power plant comprising the reactive working fluid 10, will allow an increase by 200% of the specific electrical power, specific to the mass flow rate of the working fluid, produced by such power plant, with respect to comparable inert fluids. The specific net power thus results to be tripled with respect to power plants of the state of the art.

[0201] The use of the reactive working fluid 10 in a power plant, or a powerplant comprising the reactive working fluid 10, will provide an improvement of30% efficiency (increase by +30% compared to the current efficiency achieved bypower plants according to the state of the art).

[0202] FIGURES 2 to 15 show the thermodynamic properties of seven monomer11 / dimer 12 couples, according to the invention. Each of the seven couples satis-fies to the combination of the first, third and fourth improvements.

[0203] FIGURES 2 and 3 pertains to the family 1. FIGURES 2 and 3 further pertainsto the monomer 11 / dimer 12 couple number II of family 1. The chemical structure(RiXXRi) of the monomer 11 / dimer 12 couple is ClOOCl.

[0204] FIGURES 4 and 5 pertains to the family 2. FIGURES 4 and 5 further pertainsto the monomer 11 / dimer 12 couple number XIX of family 2. The chemical struc-ture (RiXXRi) of the monomer 11 / dimer 12 couple is FClNNClF.

[0205] FIGURES 6 and 7 pertains to the family 11. FIGURES 6 and 7 further per-tains to the monomer 11 / dimer 12 couple number LXXI of family 11. The chemicalstructure (RiXXRi) of the monomer 11 / dimer 12 couple is PFPPFP.

[0206] FIGURES 8 and 9 also pertains to the family 11. FIGURES 8 and 9 furtherpertains to the monomer 11 / dimer 12 couple number LXXII of family 11. Thechemical structure (RiXXRi) of the monomer 11 / dimer 12 couple is PClPPClP.

[0207] FIGURES 10 and 11 also pertains to the family 11. FIGURES 10 and 11further pertains to the monomer 11 / dimer 12 couple number LXXIV of family 11.The chemical structure (RiXXRi) of the monomer 11 / dimer 12 couple is FNPPNF.

[0208] FIGURES 12 and 13 pertains to the family 14. FIGURES 12 and 13 furtherpertains to the monomer 11 / dimer 12 couple number LXXXVI of family 14. Thechemical structure (RiXXRi) of the monomer 11 / dimer 12 couple is SClFFSSFFClS.

[0209] Each of FIGURES 2 to 13 illustrates the two-phase domain of each mono-mer 11 / dimer 12 couple. Each of the results illustrate FIGURES 2 to 13 have beenobtained from an improved version of the Peng-Robinson Equation of State (EOS),through a Fortran code specially developed. The inputs of the code, used to calcu-late the phase diagram of each monomer 11 / dimer 12 couple according to FIG-URES 2 to 13, are the critical temperature (K), the critical pressure (bars) and theacentric factor. These inputs have been obtained by simulations using ArtificialNeural Network and the Design Institute for Physical Properties as database.

[0210] According to FIGURES 3d), 5d), 7d), 9d), 11d) and 13d), the temperature–entropy (T–s) diagram under 1 bar is illustrated. One observes that the slope ofthe saturated vapor entropy (s) of each monomer 11 / dimer 12 couple exhibits apositive slope, in particular for the couples ClOOCl, FClNNClF, PFPPFP and SClFFSS-FFClS, or at least partly positive slope, in particular for the couples FFNNFF andFNPPNF.

[0211] Moreover, the slope of saturated vapor entropy-temperature curve of themonomer 11 / dimer 12 couple is vertical or quasi vertical. Such behavior producesefficient work (in expansion) and requires a low mechanical work (in compression).

[0212] ] The saturated vapor entropy (s) of most of the current and / or usual work-ing fluids, as for instance propane, exhibits a negative slope. This leads to a com- pression process requiring more energy, since the fluid’s temperature is highly increased.

[0213] Thus, the positive slope of the saturated vapor entropy (s) of the monomer11 / dimer 12 couple is a beneficial effect for the cyclic thermodynamic machines due to a lower consumption of the compression process.

[0214] In reference to FIGURES 3d), 5d), 7d), 9d), 11d) and 13d), the inventorsalso observe that using the monomer 11 / dimer 12 couple according to the inven-tion in a cyclic thermodynamic conversion machine allows increasing the coefficientof performance (COP) of said cyclic thermodynamic conversion machines. The COPis defined as the ratio between the heat provided to the heat sink and the inputwork of the compressor 2.

[0215] As a non-limiting example, wherein the cyclic thermodynamic conversionmachine is a heat pump 1, a temperature of a heat sink is about 330 K and atemperature of a heat source is about 290 K, and compare to the propane used asworking fluid, the COP of the heat pump 1 comprising the monomer 11 / dimer 12 couple according to the invention is increased by a factor comprised between 1.7 and 3.

[0216] The increase of the COP observed in the 3d), 5d), 7d), 9d), 11d) and 13d)is the result of the specific thermodynamic features of the working fluid 10 accord-ing to the invention. In particular, the reactive character of monomer 11 / dimer 12couple enables increasing the amount of heat provided to the heat sink (becauseof the exothermic reaction due to the association of, at least a part or a part onlyor the entirety of, the monomers 12 into dimers 11), and to reduce the work re-quired by the compressor 2 (because of an endothermic reaction taking place inthe working fluid 10 during its compression).

[0217] Moreover, still according to the non-limiting example of a heat pump 1 (ascyclic thermodynamic conversion machine), considering a temperature of the heatsink of about 330 K, and a temperature of the heat source about 290 K, the in-ventors compared, at the output of the compressor 2, the temperature of themonomer 11 / dimer 12 couple (used as working fluid) and the temperature of thepropane (used as working fluid). It is observed that the reactive fluid 10 accordingto the invention leads to an important reduction of the working fluid temperatureat the output of the compressor 2 (compare to the propane); i.e. the temperatureof the monomer 11 / dimer 12 couple is lower than the temperature of the propaneafter compression.

[0218] Such a further cooling effect is particularly important for high-temperatureheat pumps applications. Indeed, this further cooling effect avoids obtaining too high temperatures at the output of the compressor 2 and, thus, it allows to achievehigher heat sink temperatures than the ones achievable with working fluids ac-cording to the state of the art.

[0219] The temperature decrease observed when using the working fluid 10 ac-cording to the invention is a consequence of the cooling effect provided by theendothermic reaction taking place during the compression phase. The temperaturedecrease observed when using the working fluid 10 according to the invention isalso a consequence of the positive slope of the saturated vapor entropy (s) of themonomer 11 / dimer 12 couple according to the invention.

[0220] According to FIGURES 3e), 5e), 7e), 9e), 11e) and 13e), the enthalpy ofvaporization of the the monomer 11 / dimer 12 couples, ΔvapH, are illustrated as afunction of the temperature.

[0221] One observes that the monomer 11 / dimer 12 couples exhibit a wide rangeof usable temperatures for enthalpy higher than 100 kJ / kg / K, typically up to 580K; in particular up to 570 K in FIGURE 3e), up to 470 K in FIGURE 5e), up to 540K in FIGURE 7e), up to 580 K in FIGURE 9e), up to 420 K in FIGURE 11e) and upto 570 K in FIGURE 13 e).

[0222] The monomer 11 / dimer 12 couples also have an enthalpy lower than 480kJ / kg / K and / or greater than 100 kJ / kg / K on a significant temperature range; inparticular: an enthalpy lower than 350 kJ / kg / K and / or greater than 100 kJ / kg / Kon the range comprised between 150 and 570 K in FIGURE 3e), an enthalpy lowerthan 260 kJ / kg / K and / or greater than 100 kJ / kg / K on the range comprised be-tween 150 and 470 K in FIGURE 5e), an enthalpy lower than 200 kJ / kg / K and / orgreater than 100 kJ / kg / K on the range comprised between 150 and 540 K in FIG-URE 7e), an enthalpy lower than 450 kJ / kg / K and / or greater than 100 kJ / kg / K onthe range comprised between 150 and 580 K in FIGURE 9e), an enthalpy lowerthan 480 kJ / kg / K and / or greater than 100 kJ / kg / K on the range comprised be-tween 150 and 420 K in FIGURE 11e) and an enthalpy lower than 160 kJ / kg / Kand / or greater than 100 kJ / kg / K on the range comprised between 150 and 570 Kin FIGURE 13e).

[0223] Thus, monomer 11 / dimer 12 couples according to the invention are usablein heat pumps, for domestic use as well as for industrial use, for instance for wasteheat recovery, compression refrigeration, in particular compression refrigerationwith heat recovery, for domestic use as well as for industrial use, and in RankineCycles, in particular in Organic Rankine Cycles.

[0224] It worth noting that the monomer 11 / dimer 12 couples exhibit slight de-crease of ΔvapH on a significant range of temperatures. The associated effects area simpler design and manufacturing of cyclic thermodynamic machines, an im-prove regulation and stability, a higher energy efficiency and / or an effective andreliable automatic control of the of the cyclic thermodynamic machines.

[0225] The invention is not restricted to embodiments described above and nu-merous adjustments may be made within the scope of the invention.

[0226] In addition, the different features, forms, variants and embodiments of theinvention can be associated with each other in various combinations as long as they are not incompatible or exclusive of each other.

[0227] Thus, in variants that can be combined with each other of the previouslydescribed embodiments: -the substituents Ri may be identical or different, in whole or in part, and / or- when j equal to 1:^ X is O, and R1 is F, Cl, Br or I, or^ X is S, and R1 is F, Br or I, or^ X is B, P, N, Cl, Br or I, and R1 is O, or^ X is B, P, N, Br or I, and R1 is S, and / or- when j equal to 1:^ X is selected from B, P, N, Cl, Br or I, and R1 and R2 are selected fromF, Cl, Br, S or I, or ^X is selected from B, P, Cl, Br or I, and R1 and R2 are selected fromF, Cl, Br, S, O or I, and / or -although the monomer 11 / dimer 12 couples comprising Iodine have notbeen detailed and described in the non-limiting embodiment, at least 50monomer 11 / dimer 12 couples comprising Iodine are found to be stable.

Claims

CLAIMS1. Reactive working fluid for cyclic thermodynamic conversion machines, saidworking fluid, comprising a monomer / dimer couple capable of reversibly associating / dissociating, during each thermodynamic cycle, by covalent bond(s) formation / breakage; said monomer / dimer couple being of formula 2(Ri-X•) / Ri-X- X-Ri, wherein: -Ri is / are substituent(s) bonded to each atom X, i being equal to 1, 2, 3, 4,5 or 6, -each Ri is different from X,- one considered substituent (Ri) is different from or identical to another,several or each of the other substituents, -j is the number of substituent(s) Ri bonded to each atom X, j beingcomprised between 1 and 6, -each Ri and X are selected from F, Cl, Br, I, O, S, B, N, P and C,- each Ri is an atom at its lowest valence state, and wherein- for j equal to 1:^ X is O, and R1 is F, Cl, Br or I, or^ X is S, and R1 is F, Br or I, or^ X is B, P, N, Cl, Br or I, and R1 is O, or^ X is B, P, N, Br or I, and R1 is S, and- for j equal to 2:^ X is selected from B, P, N, Cl, Br or I, and R1 and R2 are selected fromF, Cl, Br, S or I, or^ X is selected from B, P, Cl, Br or I, and R1 and R2 are selected fromF, Cl, Br, S, O or I.

2. Working fluid according to claim 1, wherein the monomer / dimer couple beingselected from the list of formulae 1 to 21:, formula 1, wherein X is O, and R1 is F, Cl, Br or I; or X is S, and R1 is F, Br or I,formula 2, wherein X is B, P, N, Cl, Br or I,Cl, Br and I, I,R2 is / are selected from F, Cl, Br or I, and R3 is O, S,, I,, formula 7, wherein X is C or S, and R1 is selected from O and S and R2 is selected from F, Cl, Br and I, , formula 8, wherein X is C or S, and R1 is selected from B, P and N,, formula 9, wherein X is P, Cl, Bror F, Cl, Br and I,, formula 10, wherein X is P, Cl, Br or I, and R1 is selected from O and S, and R2 and R3 is / are selected from F, Cl, I,, Cl, S,, formula 13, wherein X is S, and, formula 14, wherein X is S, and R1 is selected from O and S, and R2, R3 and R4 is / are selected from F, Cl, Br and I,, formula 15, wherein X is S,is / are selected from F, Cl, Br and, formula 16, wherein X is S, and R1 is selected from O and S, and R2, R3 and R4 is / are selected from F, Cl, Br, is selected from Cl, Br and I, and R1, R2, R3, R4, R5, R6 and R7 is / are selected from F,, formula 19, wherein X is selected from Cl, Br and I, and R1 is O or S, and R2, R3, R4, R5 is / are selected from F, Cl, Br and I,, formula 20, wherein X isor S, and R3 and R4, is / are selected from F, Cl, Br and I,, formula 21, wherein X is selected from Cl, Br and I, and R1, R2 and R3 is / are selected from O and S,, formula 22, wherein X isselected from Cl, Br and I, and R1 is B, P or N, and R2, R3 and R4 is / are selectedfrom F, Cl, Br and I,, formula 23, wherein X is selectedfrom Cl, Br and I, and R1 and R2 is / are selected from B, P and N.

3. Working fluid according to claim 1 or 2, wherein, during each thermodynamiccycle, the monomer / dimer couple undergoes at least one covalent bond formation and at least one covalent bond breakage.

4. Working fluid according to any of claims 1 to 3, being unable unable to form orto incur breakage of van der Waals bonds between dimers, between monomers and / or between monomers and dimers.

5. Use of the reactive working fluid according to claims 1 to 4 in a cyclicthermodynamic conversion machine.

6. Use of the reactive working fluid according to claims 1 to 4 in a heat pump.

7. Use of the reactive working fluid according to claims 1 to 4 in a power plant.

8. Use of the reactive working fluid according to claims 1 to 4 in a refrigerationmachine.

9. Cyclic thermodynamic conversion machine comprising means for compressinga working fluid, means arranged to cool down the working fluid, means arranged to expand the working fluid and means arranged to heat up the working fluid; theworking fluid comprises a monomer / dimer couple capable of reversiblyassociating / dissociating, during each thermodynamic cycle, by covalent bond(s) formation / breakage, said monomer / dimer couple being of formula 2(Ri-X•) / Ri-X- X-Ri, wherein: -Ri is / are substituent(s) bonded to each atom X, i being equal to 1, 2, 3, 4,5 or 6, -each Ri is different from X,- one considered substituent (Ri) is different from or identical to another,several or each of the other substituents,- j is the number of substituent(s) Ri bonded to each atom X, j beingcomprised between 1 and 6, -each Ri and X are selected from F, Cl, Br, I, O, S, B, N, P and C,- each Ri is an atom at its lowest valence state, and wherein- for j equal to 1:^ X is O, and R1 is F, Cl, Br or I, or^ X is S, and R1 is F, Br or I, or^ X is B, P, N, Cl, Br or I, and R1 is O, or^ X is B, P, N, Br or I, and R1 is S, and- for j equal to 2:^ X is selected from B, P, N, Cl, Br or I, and R1 and R2 are selectedfrom F, Cl, Br, S or I, or ^X is selected from B, P, Cl, Br or I, and R1 and R2 are selected fromF, Cl, Br, S, O or I ;said cyclic thermodynamic conversion machine is arranged to: -dissociate, at least partly, the working fluid into monomers within the meansfor compressing the working fluid, -associate, at least partly, the working fluid into dimers within the meansarranged to cool down the working fluid, -associate, at least partly, the working fluid into dimers within the meansarranged to expand the working fluid, -dissociate, at least partly, the working fluid into monomers within the meansarranged to heat up the working fluid.

10. Cyclic thermodynamic conversion machine according to claim 9, wherein saidcyclic thermodynamic conversion machine is a heat pump.

11. Cyclic thermodynamic conversion machine according to claim 9, wherein saidcyclic thermodynamic conversion machine is a power plant.

12. Cyclic thermodynamic conversion machine according to claim 9, wherein saidcyclic thermodynamic conversion machine is a refrigeration machine.

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