Device suitable for carrying out rapid quasi-isothermal compression or expansion of a gas

Abstract

Device adapted to carry out a rapid quasi-isothermal compression, or expansion, of a gas Device (12) for carrying out a compression, or respectively an expansion, of a gas (16), comprising: a body (18) at least partially defining a chamber (20) for containing the gas in a gaseous phase (22), and containing a liquid phase (24), a first system (30) for exchanging heat successively with the gaseous phase and the liquid phase, comprising a support (46) extending along an axis (Z), and a plurality of successive elements (48) defining between them interstitial spaces (50) intended to contain the gaseous phase, the first system being intended to be driven in rotation around the axis (Z) to form an interface (28) separating the liquid phase and the gaseous phase, a second system (32) for bringing the interface closer to, or respectively moving away from, the axis, a third system (34) for evacuating said heat from the liquid phase,or respectively supply said heat to the liquid phase, an inlet / outlet (36, 38) adapted to allow admission and / or discharge of the gas. Figure for the abstract: Figure 2,

Description

Title of the invention: Device suitable for carrying out rapid quasi-isothermal compression or expansion of a gas

[0001] The present invention relates to a device suitable for compressing, or respectively expanding, a gas.

[0002] The invention also relates to a thermal machine, such as a Stirling engine or a heat pump integrating at least one such device, and a method corresponding to the device.

[0003] It is known that the quasi-isothermal compression or expansion of a gas makes it possible to obtain good energy efficiency, for example in a Stirling cycle, particularly an engine.

[0004] To achieve such compression or expansion, traditional solutions are slow, in order to allow heat exchanges ensuring the quasi-isothermal character. However, these solutions, due to their slowness, do not allow good productivity to be obtained.

[0005] To increase productivity, for example, a piston / cylinder type device has been devised, the piston comprising structures promoting heat exchange at its end, these structures fitting into corresponding structures of the cylinder. These structures have, for example, the form of plates spaced slightly apart from each other. However, in order not to risk a collision between the plates, the plates must be sufficiently rigid to limit their deformation. This rigidity imposes in practice a lower limit on the spacing of these plates, which, in turn, limits the intensity of the heat transfer between the gas and the plates. Consequently, in practice in such a system, the operating frequency is limited to approximately 1 Hz.

[0006] To overcome these drawbacks, it has been considered to inject into a conventional cylinder a mist of droplets intended to receive the heat released by the compressed gas. However, it is complicated to obtain a mist that is both sufficiently dense and uniform.

[0007] This results in significant heating of the entire gas, but also local heating and a locally even more distant character of the compression from the isothermal. In practice, this solution results in an average heating of approximately 40 to 60°C, or more than 10% of the initial absolute temperature. In addition, it is necessary to separate the gas and the liquid after each compression. For these reasons, the operating frequency is limited, which results in a low power of the machine concerned.

[0008] It has also been considered to compress a liquid foam. However, the problem of phase separation persists, and is even increased by the intimate mixing necessary for the formation of a foam.

[0009] A system is also known that uses gas bubbles injected into a liquid. The emulsion is centrifuged, which compresses the gas bubbles. Then, a rotating drum creates an area where the gas concentrates, being separated from the liquid. However, this method has a major drawback: it is a continuous method, which therefore requires a pressurized gas exchanger instead of the regenerator, which is generally much cheaper and more efficient than a pressurized exchanger. This also rules out many applications where expansion occurs, such as in a Stirling engine, and even if an expansion method works, there remains the problem of the cost and inefficiency of the exchanger compared to a regenerator. Finally, this machine requires sliding seals, which limit the temperature that can be reached.

[0010] It is also known to use liquid pistons. A volume of gas is located above a liquid. When the liquid level rises, the gas is compressed. To increase the energy efficiency of compression in a liquid piston system, there are two types of solutions: the low height cylinder, or the small diameter cylinder.

[0011] In the case of a low-height cylinder, the large exchange surface at the gas / liquid interface is supposed to allow the heat of compression to be removed. However, the large exchange surface between the gas and the liquid (usually water), in addition to promoting heat exchange, also promotes the dissolution of the gas in the liquid, and sometimes, the evaporation of the liquid in the gas. This can create phenomena that are difficult to control, such as the condensation of liquid in the gas circulation pipes or the diffusion of bubbles in the liquid. These systems also require a very large number of valves for the admission of gas at slightly different pressures.

[0012] In the case of the small diameter cylinder, the problem lies elsewhere. Indeed, to obtain a substantial compressed active volume, it is advantageous to have very long tubes. However, such tubes, containing a gas / liquid mixture with oscillating movement, are subject to the so-called Rayleigh-Taylor instability, which rapidly causes mixing of the phases. This mixing has the effect, for example, of a risk of blocking the gas outlet tube by liquid. To avoid Rayleigh-Taylor instability, i.e. the mixing of liquid and gas when the liquid is shaken, one of the known solutions is to greatly reduce the diameter of the tubes. Capillary forces then become significant, and can locally stabilize the interface between the gas and the liquid. The diameter of the tubes must therefore be less than approximately 1 mm, depending on the liquid and the acceleration forces to be contained. Therefore, to obtain a significant volume, the number of tubes must become very large (several hundred thousand, ideally a few million). This makes the practical realization of such a system extremely complex.

[0013] Furthermore, while capillarity in each tube allows fluids to be kept in the desired regions locally, it does nothing to prevent instability from developing between two tubes connected by their liquid phase, by siphon effect. Thus, capillarity does not appear to provide a satisfactory solution.

[0014] An aim of the invention is therefore to remedy all or part of the above drawbacks, by providing a device suitable for carrying out compression, or respectively expansion, of a gas in a quasi-isothermal manner, with good productivity, while remaining relatively simple to construct and of a competitive cost.

[0015] To this end, the invention relates to a device suitable for carrying out compression, or respectively expansion, of a gas, comprising:

[0016] - a body at least partially defining a chamber adapted to contain the gas in at least one gas phase, and to contain a liquid phase separated from the gas phase by an interface,

[0017] - a first system adapted to exchange heat successively with the gas phase and with the liquid phase, the first system comprising a support extending along an axis in the chamber, and a plurality of elements extending from the support radially relative to the axis, the elements being successive along the axis and defining between them a plurality of interstitial spaces intended to contain the gas phase, at least the first system being intended to be rotated around the axis relative to a local reference point to form the interface, the first system defining passages between the interstitial spaces to ensure fluidic continuity of the gas phase,

[0018] - a second system adapted to allow a displacement of the liquid phase which brings closer, or respectively moves away, the interface of the axis in the interstitial spaces, to obtain the compression, or respectively the expansion, of the gas, the first system being adapted to receive said heat from the gas phase during the compression, or respectively to transfer said heat to the gas phase during the expansion, then transfer said heat to the liquid phase after the compression, or respectively to receive said heat from the liquid phase after the expansion,

[0019] - a third system adapted to evacuate said heat from the liquid phase, or respectively supply said heat to the liquid phase, and

[0020] - at least one inlet / outlet adapted to allow admission and / or re gas flow between the gas phase and the outside of the device.

[0021] According to particular embodiments, the device comprises one or more of the following characteristics, taken alone or in all technically possible combinations:

[0022] - the elements extend orthogonally to the axis;

[0023] - the elements have a circular shape when viewed along the axis;

[0024] - the elements comprise perforations forming at least some of said passages;

[0025] - the first system is configured so that any point in the gas phase is located at a distance from the first system, said distance being less than 1.0 mm, preferably less than 0.25 mm; and / or any two successive elements taken from among said elements are separated by a distance parallel to the axis of between 0.05 and 2.0 mm, preferably between 0.05 and 0.50 mm;

[0026] - the first system is integral with the body and / or the second system, or mounted freely rotatable on a wall of the body or second system about the axis, the body being intended to be rotated about the axis to form the interface;

[0027] - the first system comprises separators oriented radially with respect to the axis and adapted to separate at least some of the interstitial spaces into several sectors;

[0028] - the second system comprises: a piston, the body forming a cylinder in which the piston is mounted movably; a bellows or a membrane; and / or a hydraulic pump;

[0029] - the third system comprises: fins fixed on an external surface of the body relative to the chamber; a coil extending into the chamber, adapted to be in thermal contact with the liquid phase, and intended to be traversed by a heat transfer fluid; or an inlet and an outlet for the liquid phase, the liquid phase being intended to exchange said heat with the exterior of the device.

[0030] The invention also relates to a thermal machine, in particular a motor and / or a heat pump, integrating at least one device as described above.

[0031] The invention also relates to a method for carrying out compression, or respectively expansion, of a gas, comprising the following steps:

[0032] - obtaining a device as described above, or a thermal machine such as as described above,

[0033] - rotational drive at least of the first system around the axis relative to a local reference point to form the interface in the chamber,

[0034] - admission of gas into the chamber and obtaining the gas phase in the spaces interstitials, the liquid phase and the gas phase being separated by the interface,

[0035] - displacement of the liquid phase due to the second system to bring together, or respectively move away, the interface of the axis in the interstitial spaces and thus obtain the compression, or respectively the expansion, of the gas, the first system receiving heat from the gas phase during compression, or respectively giving up heat to the gas phase during expansion,

[0036] - gas discharge from the chamber,

[0037] - transfer of said heat by the first system to the liquid phase after the com pressure, or respectively reception of said heat by the first system from the liquid phase after expansion, and

[0038] - evacuation of said heat from the liquid phase by the third system after said compression of the gas, or respectively supply of said heat to the liquid phase by the third system after said expansion of the gas.

[0039] The invention will be better understood on reading the following description, given solely by way of example and with reference to the appended drawings, in which:

[0040] [Fig-1] [Fig.l] is a schematic view of a thermal machine comprising two devices according to the invention,

[0041] [Fig.2] [Fig.2] is a schematic view, in section, of one of the two devices re shown in [Fig.l], the second system of this device (allowing the liquid to be moved) being in a first position (high) relative to the body, in which the gas / liquid interface is close to the axis,

[0042] [Fig.3] [Fig.3] is a view similar to that of [Fig.2], the second system of the device being in a second (low) position relative to the body, in which the interface is away from the axis,

[0043] [Fig.4] [Fig.4] is a schematic view, along the axis, of one of the elements of the first system of the device shown in Figures 1 to 3,

[0044] [Fig.5] [Fig.5] is a view similar to that of [Fig.4], showing an element constituting a variant of the element represented in [Fig.4],

[0045] [Fig.6] [Fig.6] is a view similar to that of [Fig.2], showing a device constituting a first variant of the device shown in figures 1 to 3,

[0046] [Fig.7] [Fig.7] is a view similar to that of [Fig.2], showing a device constituting a second variant of the device shown in Figures 1 to 3,

[0047] [Fig.8] [Fig.8] is a view similar to that of [Fig.2], showing a device constituting a third variant of the device shown in Figures 1 to 3,

[0048] [Fig.9] [Fig.9] is a view similar to that of [Fig.2], showing a device constituting a fourth variant of the device shown in Figures 1 to 3,

[0049] [Fig. 10] [Fig. 10] is a view similar to that of [Fig.2], showing a device constituting a fifth variant of the device shown in Figures 1 to 3,

[0050] [Fig. 11] [Fig. 11] is a view similar to that of [Fig.2], showing a device constituting a sixth variant of the device shown in Figures 1 to 3,

[0051] [Fig. 12] [Fig. 12] is a view similar to that of [Fig. 2], showing a device constituting a seventh variant of the device shown in Figures 1 to 3, and

[0052] [Fig. 13] [Fig. 13] is a view similar to that of [Fig.2], showing a device constituting an eighth variant of the device shown in Figures 1 to 3. Heat engine

[0053] With reference to [Fig.l], a thermal machine 10 according to the invention is described, in particular an engine, for example a Stirling engine.

[0054] In the example, the thermal machine 10 comprises two devices 12, 14 according to the invention, respectively adapted to carry out quasi-isothermal compression and expansion of a gas.

[0055] By "quasi-isothermal" is meant within the meaning of the present document that, for example, the variation in temperature between the start and the end of the compression, for a compression ratio (ratio of the final pressure divided by the initial pressure) of at least 1.5, is in absolute value less than 10%, preferably less than 5.0%, and even more preferably less than 3.0% of the initial absolute temperature.

[0056] In the case of an expansion, the temperature variation between the start and the end of the expansion, for an expansion ratio (ratio of the initial pressure divided by the final pressure) of at least 1.5, is less in absolute value than 10%, preferably less than 5.0%, and even more preferably less than 3.0% of the initial absolute temperature.

[0057] In summary:

[0058] Savec: 7, a

[0059] T; initial temperature in K,

[0060] AT temperature variation, considered here in absolute value (without its sign),

[0061] a coefficient equal to 10%, preferably 5.0%, and even more preferably 3.0%.

[0062] Alternatively, the thermal machine 10 only comprises the device 12, the expansion being carried out by another device (not shown) known in itself.

[0063] According to yet another variant, the thermal machine 10 only comprises the device 14, the compression being carried out by another device (not shown) known in itself.

[0064] Alternatively, the heat engine 10 is not a motor, but a heat pump.

[0065] The two devices 12, 14 are advantageously similar, so only the device 12 will be described below with reference to FIGS. 2 to 4. Structure of the compression / expansion device

[0066] The device 12 is adapted to carry out a compression, or an expansion, advantageously quasi-isothermal, of a gas 16.

[0067] The device 12 comprises a body 18 at least partially defining a chamber 20 adapted to contain the gas in at least one gaseous phase 22, and to contain a liquid phase 24 separated from the gaseous phase 22 by an interface 28.

[0068] In the example, the liquid phase 24 forms a liquid ring 26, the liquid ring surrounding the gas phase 22 around an axis Z of the device 12.

[0069] “Liquid ring” is to be taken possibly in the broad sense of a liquid phase which continuously surrounds the gas phase 22 around the Z axis, and which can therefore have a geometric shape quite far from a ring in the current sense of the term.

[0070] According to a variant not shown, the liquid phase 24 does not form a liquid ring. For example, the device forms several chambers or sectors (not shown) in which the gas phase is separated from liquid phases distinct from each other respectively by interfaces. The distinct liquid phases then do not form a ring.

[0071] The Z axis, shown vertical in the figures, is not necessarily vertical relative to the ground. According to one embodiment, the Z axis is horizontal. In other embodiments, the Z axis has any orientation relative to the ground.

[0072] The device 12 comprises a first system 30 adapted to exchange heat successively with the gas 16 and with the liquid phase 24, and a second system 32 adapted to allow a movement of the liquid phase 24 which brings the interface 28 closer to, or respectively further away from, the Z axis, and a third system 34 adapted to evacuate said heat from the liquid phase 24, or respectively supply said heat to the liquid phase 24.

[0073] In the example, the device 12 comprises an inlet 36 and outlet 38 adapted to allow respectively an admission and a discharge of the gas 16 between the gas phase 22 and the exterior of the device 12.

[0074] The first system 30, and possibly the body 18, is / are intended to be driven in rotation around the axis Z relative to a local reference frame R by one or more systems not shown and known per se, to set the liquid phase 24 in rotation and form the interface 28 due to centrifugal forces exerted on the liquid phase.

[0075] According to a preferred embodiment, the first system 30 is integral with the body 18, the body 18 being intended to be driven in rotation around the axis Z relative to the local reference frame R. This minimizes viscous dissipation.

[0076] According to a variant (not shown) also making it possible to minimize viscous dissipation, the first system 30 is mounted freely rotatably on a wall 40 of the body 18 around the axis Z, the body being intended to be driven in rotation around the axis Z relative to the local reference frame R.

[0077] According to yet another variant, the first system 30 is rotatably mounted on the wall 40 around the axis Z, the body 18 and the first system 30 being intended to be driven rotating around the Z axis relative to the local reference frame R at different speeds from each other.

[0078] These variants optionally include an additional seal (not shown) between the body 18 and the first system 30.

[0079] According to still other variants (not shown), the first system 30 is integral with the second system 32, or the wall 40 on which the first system 30 is rotatably mounted (freely or not) belongs to the second system 32 and not to the body 18.

[0080] According to a preferred embodiment, the body 18, the first system 30 and the second system 32 are integral with each other.

[0081] The body 18 forms for example a cylinder 41 comprising a bottom 42, and defining an opening 44 axially opposite the bottom.

[0082] The first system 30 is adapted to receive the heat produced by the gaseous phase 22 during compression, or respectively to transfer heat to the gaseous phase 22 which tends to cool during expansion, then to transfer said heat to the liquid phase 24 after compression, or respectively to receive said heat from the liquid phase 24 after expansion.

[0083] Advantageously, the first system 30 is configured so that any point M of the gas phase is located at a distance DI from the first system, said distance DI being less than 1.0 mm, preferably less than 0.25 mm. This guarantees a quasi-isothermal character during expansion or compression.

[0084] The first system 30 comprises a support 46 mounted on at least said wall 40 and extending along the Z axis in the chamber 20, and a plurality of elements 48 extending from the support radially relative to the Z axis.

[0085] The first system 30 is for example made of metal, preferably steel, advantageously stainless steel, or ceramic.

[0086] The support 46 is for example cylindrical around the Z axis, and advantageously forms a shaft.

[0087] The elements 48 are successive along the Z axis and define between them a plurality of interstitial spaces 50 intended to contain at least a part of the gas phase 22.

[0088] In the example, the wall 40 and the element 48 closest to the wall also form an interstitial space 52 which possibly contains the remainder of the gas phase 22.

[0089] In the example, only five elements 48 are shown to simplify the figures, but in practice there are a greater number, advantageously greater than 20, and for example between 50 and 500.

[0090] In the example, the elements 48, except the one furthest from the wall 40, define passages 54 between the interstitial spaces 50, 52 to ensure fluid continuity. of the gas phase 22. In other words, it is indeed a gas phase distributed in the interstitial spaces 50, 52, and not gas phases separated from each other.

[0091] However, it is not excluded that, in other embodiments (not shown), the chamber 20 contains other gaseous phases independent of the gaseous phase 22.

[0092] The elements 48 extend for example orthogonally to the Z axis.

[0093] The elements 48 advantageously have a circular shape when viewed along the Z axis ([Fig.4]).

[0094] According to a particular embodiment, the elements 48 form discs or rings centered on the Z axis.

[0095] According to another particular embodiment (not shown), the elements 48 do not surround, or do not completely surround, the Z axis. For example, each of the elements 48 extends in an angular sector (not shown) defined from the Z axis.

[0096] The elements 48 comprise, for example, perforations 56 forming the passages 54 between the interstitial spaces.

[0097] Advantageously, any two successive elements 48 taken from among the elements are separated by a distance D2, for example measured parallel to the Z axis, between 0.05 and 2.0 mm, preferably between 0.05 and 0.50 mm. This again guarantees a quasi-isothermal character.

[0098] The perforations 54 are advantageously located near the support 46, so as to ensure the fluidic continuity of the gas phase 22 even when the interface 28 is close to the Z axis.

[0099] The perforations 54 are for example of dimensions 2 mm x 0.5 mm.

[0100] According to a variant shown in [Fig.5], the first system 30 comprises separators 58 oriented radially relative to the Z axis and adapted to separate at least some of the interstitial spaces 50 into several angular sectors 60. These separators 58 make it possible to reduce the influence of the Coriolis force when the interface 28 approaches the Z axis.

[0101] Advantageously, all the interstitial spaces 50, 52 contain separators 58, except possibly the one located against the wall 40.

[0102] The separators 58 are for example fixed on two consecutive elements 48.

[0103] The number of separators 58 (and therefore of sectors 60) is for example between four and ten in each of the interstitial spaces 50, 52 concerned.

[0104] The passages 54 also ensure fluid continuity between the sectors 60.

[0105] In the example, the second system 32 does not directly displace the liquid phase 24, but acts by increasing (expansion) or reducing (compression) the volume of the chamber 20 accessible to the liquid phase.

[0106] The second system 32 comprises for example a piston 62, axially movable in the cylinder formed by the body 18 between a first position ([Fig.2]) and a second position ([Fig.3]).

[0107] The second system 32 is adapted to be actuated by a system not shown and known in itself.

[0108] The second system 32 is advantageously rotating around the Z axis relative to the local reference frame R at the same angular speed as the body 18.

[0109] In the first position, the interface 28 is close to the Z axis, the piston 62 being closer to the wall 40.

[0110] In the second position, the interface 28 is further from the Z axis than in the first position but remains in the interstitial spaces 50, 52, the piston 62 being further from the wall 40 than in the first position.

[0111] The third system 34 comprises, for example, fins 64 fixed to an external surface 66 of the body 18 relative to the chamber.

[0112] The inlet 36 and the outlet 38 are for example arranged in the wall 40 and open into the interstitial space 52.

[0113] The inlet 36 and the outlet 38 are advantageously equipped with valves (not shown and known per se) making it possible to control the admission of the gas 16 into the chamber 20 via the inlet 36, and the discharge of the gas 16 out of the chamber 20 via the outlet 38.

[0114] Alternatively, the inlet 36 and the outlet 38 are without valves, the admission and discharge of the gas 16 being controlled by other means (not shown) located outside the device.

[0115] The gas 16 is for example helium, hydrogen (H2), air, or nitrogen (N2), the two gases mentioned first being preferred, because they allow a faster heat exchange between the gas and the first system 30.

[0116] The liquid 24 is for example water, a thermal oil, in particular for operating temperatures of the device 12 up to 300°C, or comprises molten salts, in particular salts of sodium and potassium nitrates and / or nitrites, in particular for operating temperatures up to 550 to 600°C, or salts of hydroxides and / or carbonates, in particular for operating temperatures up to 600°C, or even 700°C or 800°C.

[0117] The angular speed of the rotating parts (body 18 and / or first system 30 in particular) is advantageously chosen to be sufficiently high to obtain a perfectly stable interface 28, i.e. an absence of significant mixing between the gas phase 22 and the liquid phase 24.

[0118] The interface 28 is for example of substantially cylindrical shape around the axis Z, except possibly in the interstitial space 52 located against the wall 40 if the body 18 and the first system 30 are in relative rotation with respect to each other. Functioning

[0119] The operation of the device 12 shown in Figures 1 to 3 will now be described. It illustrates a method according to the invention.

[0120] The first system 30 and possibly the body 18, is / are driven in rotation around the axis Z relative to the local reference frame R to form the interface 28, and in example the liquid ring 26, in the chamber 20, due to the centrifugal forces (not shown) exerted on the liquid phase 24. These centrifugal forces tend to move the liquid away from the axis Z. Advantageously, a dynamic equilibrium is created.

[0121] The liquid ring 26, if present, surrounds the gas phase 22 around the Z axis, the liquid ring and the gas phase forming the interface 28 between them.

[0122] The operation of the device 12 is advantageously cyclical and defines an operating frequency (number of compressions or expansions carried out per second).

[0123] The operating frequency is advantageously greater than 5 Hz, preferably greater than 10 Hz. The operating frequency can for example be up to 20 Hz or more. Compression or expansion is therefore rapid.

[0124] The first system 30 is rotating around the Z axis relative to the local reference frame R to obtain phase separation between liquid and gas and to allow the device 12 to work at a relatively high frequency.

[0125] To perform compression, the second system 32 is initially in the first position ([Fig.2]).

[0126] The second system 32 is moved from the first position to the second position. In the example, the piston 62 descends.

[0127] This allows the displacement of the liquid phase 24 and the gas 16 is admitted at low pressure into the chamber 20 via the inlet 36 into the gas phase 22, present in the interstitial spaces 50, 52. The interface 28 moves away from the Z axis in the interstitial spaces 50, 52 and then occupies the position shown in [Fig.3].

[0128] The second system 32 then moves the liquid 24 to bring the interface 28 closer to the Z axis again and obtain compression of the gas 16. In the example, the piston 62 rises. The interface 28 this time occupies an intermediate position (not shown) between that shown in [Fig.3] and that shown in [Fig.2].

[0129] The compression generates heat in the gas phase 22. The first system 30 receives heat from the gas phase 22 generated during the compression.

[0130] Finally, the piston completes its rise to its high position, described in [Fig.2]. The gas 16 is then forced at high pressure out of the chamber 20 via the outlet 38. The interface 28 moves closer to the Z axis and again occupies the position shown in [Fig.2]. The liquid phase 24 partially fills the interstitial spaces 50, 52.

[0131] The heat received by the first system 30 during the previous step is then transferred by the first system to the liquid phase 24 after compression.

[0132] The heat received by the liquid phase 24 is then evacuated by the third system 34.

[0133] Now, in order to be able to achieve an expansion from the position of [Fig.2], the gas 16 is admitted at high pressure via the inlet 36 by displacing the liquid phase 24 using the second system 32. In the example, the piston 62 descends.

[0134] The interface 28 moves from the position shown in [Fig. 2] to an intermediate position (not shown) between those of Figures 2 and 3. Once the gas is admitted, the liquid phase 24 is moved further to move the interface 28 further away from the Z axis, to the position shown in [Fig. 3], and thus obtain expansion. In the example, the piston 62 descends completely, to its position shown in [Fig. 3]. The expansion generates cold, and the first system 30 gives off heat to the gas phase 22.

[0135] Then, the gas 16 is discharged at low pressure via the outlet 38, while the second system 32 moves the interface 28 towards the Z axis, to the position shown in [Fig.2],

[0136] Then, the liquid phase 24 gives off heat to the first system 30 and this same liquid phase 24 receives heat from the third system 34.

[0137] Thanks to the characteristics described above, the gas phase 22 quickly transfers heat to the first system 30 during compression, or quickly receives heat from the first system 30 during expansion, which allows for quasi-isothermal compression or expansion. Compression and expansion are achieved by rapidly moving the interface 28 closer to or further away from the Z axis, obtained by moving the liquid phase 24. The device 12 is therefore suitable for achieving both quasi-isothermal compression or expansion, and in a very productive manner, of a gas. The device 12 also remains relatively simple to construct and of competitive cost.

[0138] The device 12 may operate at pressure levels above or below atmospheric pressure.

[0139] Depending on the nature of the liquid 24, the device 12 can operate from low temperatures, for example ambient temperature, or even between -20°C for thermal oils and -150°C for liquefied gases, up to very high temperatures, for example 600-800°C. Variants

[0140] With reference to Figures 6 to 13, devices 12 are described which are variants of the device 12 shown in Figures 1 to 3. These devices 12 are analogous to the device 12 shown in Figures 1 to 3. Similar elements bear the same numerical references and will not be described again. Only the differences will be described in detail below.

[0141] First variant ([Fig.6])

[0142] In the first variant, the third system 34 does not include the fins 64, but an inlet 102 and an outlet 104 for the liquid phase 24, the liquid phase 24 being intended to exchange the heat that it receives from the first system 30 (compression) or that it gives up to the first system (expansion) outside the device 12.

[0143] The inlet 102 and the outlet 104 are for example provided in the body 18.

[0144] Alternatively, the inlet 102 and the outlet 104 are for example provided in the piston 62.

[0145] Second variant ([Fig.7])

[0146] In the second variant, the third system 34 does not include the fins 64, but a coil 106.

[0147] The coil 106 extends into the chamber 20. The coil 106 is adapted to be in thermal contact with the liquid phase 24, and intended to be traversed by a heat transfer fluid 108.

[0148] The coil 106 comprises for example an inlet section 110 and an outlet section 112 located in the piston 62.

[0149] Alternatively (not shown), the inlet section 110 and the outlet section 112 are located in the body 18.

[0150] Third variant ([Fig.8])

[0151] In the third variant, the second system 32 does not only comprise a piston 62, but a bellows 116 or a membrane, joined to the piston 62, and intended to maintain a seal between the piston 62 and the body 18.

[0152] Fourth variant ([Fig.9])

[0153] In the fourth variant, the second system 32 does not include the piston 62, but a hydraulic pump 118, possibly reversible into a pump / turbine.

[0154] Fifth variant ([Fig. 101)

[0155] In the fifth variant, the inlet 36 and the outlet 38 are replaced by a single inlet / outlet 120, advantageously arranged in the support 46 of the first system 30 and opening for example into the first interstitial space 50 closest to the wall 40.

[0156] The gas phase 22 is for example absent between the wall 40 and the adjacent element 48. In other words, the interstitial space 50 does not contain gas.

[0157] Sixth variant ([Fig.l 11)

[0158] In the sixth variant, the inlet 36 and the outlet 38 are replaced by a single inlet / outlet 122 advantageously provided in the support 46 and opening into each of the interstitial spaces 50.

[0159] The inlet / outlet 122 forms passages 54 between the interstitial spaces 50 and ensures the fluidic continuity of the gas phase 22. The perforations 56 are then useless.

[0160] Seventh variant ( [Fig. 12] )

[0161] In the seventh variant, the element 48 closest to the wall 40 has a diameter D3 greater than the diameter D4 of the other elements 48.

[0162] Indeed, the first system 30 and the body 18 are possibly in relative rotation with respect to each other around the Z axis and the interface 28 is likely to come closer to the Z axis in the interstitial space 52 adjacent to the wall 40, than in the other interstitial spaces 50. Indeed, the average rotation speed of the liquid phase 24 in the interstitial space 52 is possibly lower than in the spaces 50 and there is a risk that the inlet 36 and the outlet 38 are “flooded” (find themselves in contact with the liquid phase 24).

[0163] Eighth variant ([Fig. 131)

[0164] In the eighth variant, the elements 48 are not orthogonal to the Z axis, but inclined.

Claims

1.

2.

3. Claims Device (12) adapted to carry out a compression, or respectively an expansion, of a gas (16), comprising: - a body (18) at least partially defining a chamber (20) adapted to contain the gas (16) in at least one gaseous phase (22), and to contain a liquid phase (24) separated from the gaseous phase (22) by an interface (28), - a first system (30) adapted to exchange heat successively with the gas phase (22) and with the liquid phase (24), the first system (30) comprising a support (46) extending along an axis (Z) in the chamber (20), and a plurality of elements (48) extending from the support (46) radially with respect to the axis (Z), the elements (48) being successive along the axis (Z) and defining between them a plurality of interstitial spaces (50) intended to contain the gas phase (22), at least the first system (30) being intended to be driven in rotation about the axis (Z) with respect to a local reference point (R) to form the interface (28), the first system (30) defining passages (54) between the interstitial spaces (50) to ensure fluidic continuity of the gas phase (22), - a second system (32) adapted to allow a displacement of the liquid phase (24) which brings closer, or respectively moves away, the interface (28) from the axis (Z) in the interstitial spaces (50), to obtain the compression, or respectively the expansion, of the gas (16), the first system (30) being adapted to receive said heat from the gas phase (22) during the compression, or respectively transfer said heat to the gas phase (22) during the expansion, then transfer said heat to the liquid phase (24) after the compression, or respectively receive said heat from the liquid phase (24) after the expansion, - a third system (34) adapted to evacuate said heat from the liquid phase (24), or respectively supply said heat to the liquid phase (24), and - at least one inlet / outlet (36, 38) adapted to allow admission and / or discharge of the gas (16) between the gas phase (22) and the exterior of the device (12). Device (12) according to claim 1, wherein the elements (48) extend orthogonally to the axis (Z). Device (12) according to claim 1 or 2, wherein the elements (48) have a circular shape when viewed along the (Z) axis.

4. A device (12) according to any one of claims 1 to 3, wherein the elements (48) comprise perforations (56) forming at least some of said passages (54).

5. Device (12) according to any one of claims 1 to 4, wherein: - the first system (30) is configured so that any point (M) of the gas phase (22) is located at a distance (D1) from the first system (30), said distance (D1) being less than 1.0 mm, preferably less than 0.25 mm; and / or - any two successive elements (48) taken from said elements (48) are separated by a distance (D2) parallel to the axis (Z) of between 0.05 and 2.0 mm, preferably between 0.05 and 0.50 mm.

6. Device (12) according to any one of claims 1 to 5, in which the first system (30) is integral with the body (18) and / or the second system (32), or mounted freely rotatably on a wall (40) of the body (18) or of the second system (32) around the axis (Z), the body (18) being intended to be driven in rotation around the axis (Z) to form the interface (28).

7. Device (12) according to any one of claims 1 to 6, wherein the first system (30) comprises separators (58) oriented radially relative to the axis (Z) and adapted to separate at least some of the interstitial spaces (50) into several sectors (60).

8. Device (12) according to any one of claims 1 to 7, in which the second system (32) comprises: - a piston (62), the body (18) forming a cylinder (41) in which the piston (62) is mounted movably, - a bellows (116) or a membrane, and / or - a hydraulic pump (118).

9. Device (12) according to any one of claims 1 to 8, in which the third system (34) comprises: - fins (64) fixed on an external surface (66) of the body (18) relative to the chamber (20), - a coil (106) extending in the chamber (20), adapted to be in thermal contact with the liquid phase (24), and intended to be traversed by a heat transfer fluid (108), or - an inlet (102) and an outlet (104) for the liquid phase (24), the liquid phase (24) being intended to exchange said heat with the exterior of the device (12).

10. Thermal machine (10), in particular a motor and / or a heat pump, integrating at least one device (12) as described by any one of claims 1 to 9.

11. Method for carrying out a compression, or respectively an expansion, of a gas (16), comprising the following steps: - obtaining a device (12) as described by any one of claims 1 to 9, or a thermal machine (10) as described by claim 10, - driving in rotation at least the first system (30) around the axis (Z) relative to a local reference point (R) to form the interface (28) in the chamber (20), - admission of the gas (16) into the chamber (20) and obtaining the gas phase (22) in the interstitial spaces (50, 52), the liquid phase (24) and the gas phase (22) being separated by the interface (28), - displacement of the liquid phase (24) due to the second system (32) to bring closer, or respectively move away, the interface (28) from the axis (Z) in the interstitial spaces (50, 52) and thus obtain the compression, or respectively the expansion, of the gas (16), the first system (30) receiving heat from the gas phase (22) during the compression, or respectively giving off heat to the gas phase (22) during the expansion, - discharge of gas (16) out of the chamber (20), - transfer of said heat by the first system (30) to the liquid phase (24) after compression, or respectively reception of said heat by the first system (30) from the liquid phase (24) after expansion, and - evacuation of said heat from the liquid phase (24) by the third system (34) after said compression of the gas (16), or respectively supply of said heat to the liquid phase (24) by the third system (34) after said expansion of the gas (16).

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