Differential evaporation system

Abstract

The invention relates to a differential evaporation engine system comprising an enclosure (11) that has a cavity capable of containing a liquid (2) and a gas mixture (3), a heat source (14) configured to heat the liquid (2), a cold source (15) configured to cool the gas mixture (3), and a movable element configured to move inside the enclosure (11), the movable element comprising at least one plunger element (122), the plunger element (122) being configured so as to be at least partially submerged in the liquid (2) in a first configuration and alternately in contact with the gas mixture (3) in a second configuration. The at least one plunger element (122) has a porous surface (122a) so as to increase evaporation area without increasing the area of the liquid (2).

Description

[0001] "Differential evaporation system"

[0002] TECHNICAL FIELD

[0003] The present invention relates to the field of energy transformation devices and more particularly to thermal machines and engines. The invention will find particular application in differential evaporation pressure engines.

[0004] STATE OF THE ART

[0005] In the field of engines, the Stirling engine is well known, which exploits a temperature difference applied to a gas in a closed enclosure to produce mechanical energy. Engines reproducing a Rankine cycle by converting heat into mechanical work are also known. However, these engines have the disadvantage of often having unsatisfactory efficiencies.

[0006] There are solutions suitable for use in an engine, such as that of document WO2016034632A1 presenting a differential evaporation engine comprising: an enclosure with a liquid and a working mixture, a cold source suitable for cooling the working mixture, a hot source configured to heat the liquid, a mobile element, arranged inside the enclosure so as to create conditions for evaporation of the liquid or condensation of the working mixture.

[0007] This type of engine is configured so that a heat exchange occurs between the working mixture and the hot and cold sources. This type of engine has high efficiency and many advantages. Naturally, it would be advantageous to further improve the efficiency and / or power of this type of engine. An object of the present invention is therefore to propose a solution that makes it possible to increase the efficiency and / or power of differential evaporation engines.

[0008] Other objects, features, and advantages of the present invention will become apparent from the following description and accompanying drawings. It is understood that other advantages may be incorporated.

[0009] SUMMARY

[0010] To achieve this objective, according to one embodiment, a differential evaporation engine system is provided comprising:

[0011] - an enclosure having a cavity capable of containing a liquid and a gaseous mixture,

[0012] - a hot source configured to heat the liquid,

[0013] - a cold source configured to cool the gas mixture,

[0014] - a movable element configured to move inside the enclosure, the movable element comprising at least one plunger element, the plunger element being configured so as to be at least partially immersed in the liquid in a first configuration and alternately in contact with the gas mixture in a second configuration, the second configuration being different from the first configuration, in the second configuration, the plunger element being not immersed in the liquid or being less immersed in the liquid than in the first configuration.

[0015] The engine is configured such that the at least one plunger element has a porous surface, the plunger element being configured such that, in the first configuration, the porous surface is impregnated with a portion of the liquid and that, in the second configuration, said portion of the liquid evaporates at least partially upon contact with the gas mixture.

[0016] The plungers make it possible to increase the evaporation surface of the liquid in contact with the gas mixture without increasing the volume of the enclosure. In other words, the present invention makes it possible to maintain a constant working volume while increasing the imbibition surface on which an evaporation and / or condensation phenomenon occurs. This leads to an unexpected increase in the efficiency and / or power of the engine.

[0017] The invention preferably makes it possible not to increase the parasitic working volume of a differential evaporation engine by increasing its evaporation or condensation surface. Unlike a Stirling engine, this technical solution allows operation with a much smaller volume of displaced gas mixture.

[0018] This results in a reduced overall size of the differential evaporation engine for a power equivalent to a larger engine. The invention allows an improvement in all systems using evaporation and / or condensation phenomena.

[0019] Without knowledge of the present invention, a person skilled in the art would increase the power of differential evaporation engines by increasing, for example, the power of the hot and cold sources or the size of the moving element.

[0020] Thus, the present invention makes it possible to avoid having to increase the surface area of ​​the liquid or to increase the size of the enclosure where the heat exchanges take place. BRIEF DESCRIPTION OF THE FIGURES

[0021] The aims, objects, as well as the characteristics and advantages of the invention will emerge more clearly from the detailed description of an embodiment thereof which is illustrated by the following accompanying drawings in which:

[0022] Figures 1A and 1B represent a sectional view of an example of a differential evaporation engine system having a movable element capable of being driven in translation and not comprising plunger elements respectively in a second and in a first configuration.

[0023] Figures 2A and 2B show a sectional view of an example of a differential evaporation engine system having a movable element capable of being driven in translation and comprising plunger elements respectively in the second configuration and in the first configuration.

[0024] Figures 3A and 3B respectively represent a sectional view of an example of a differential evaporation engine having a mobile element capable of being driven in translation and comprising plunger elements fixed on the mobile element as well as additional plunger elements fixed inside the enclosure in a second configuration and in a first configuration.

[0025] Figures 4A and 4B respectively represent a front and side sectional view of an example of a differential evaporation engine system having a movable element and comprising plunger elements capable of being driven in rotation about a transverse axis. The drawings are given by way of example and are not limiting of the invention. They constitute schematic representations of principle intended to facilitate the understanding of the invention and are not necessarily to the scale of practical applications. The cylinders or pistons are not shown in the drawings. For the sake of clarity, only the displacer is shown.

[0026] DETAILED DESCRIPTION

[0027] Before commencing a detailed review of embodiments of the invention, optional features which may possibly be used in combination or alternatively are set out below:

[0028] According to one example, the enclosure is configured so that the liquid is surmounted by the gas along a main axis and the movable element moves by a translational movement along the main axis.

[0029] In one example, the main axis is vertical.

[0030] In one example, the plunger element extends primarily in a direction parallel to the main axis.

[0031] In one example, the movable member includes a main portion having a lower surface normal to the main axis and the at least one plunger member extending from the lower surface, preferably the plunger member having a rod shape.

[0032] According to one example, the enclosure comprises at least one additional plunger element fixed relative to the enclosure and having an additional porous surface portion, the at least one additional plunger element extending into the enclosure from a lower enclosure face of the enclosure in a direction parallel to the main axis.

[0033] Preferably, the additional plunger elements are fixed relative to an upper portion of the enclosure along the main axis.

[0034] In one example, the main portion of the movable element defines a reservoir configured to contain an additional liquid and the motor is configured such that, in the second configuration, the at least one additional plunger element soaks up the additional liquid.

[0035] In one example, the engine includes a plurality of additional plunger elements.

[0036] According to one example, the enclosure is configured so that the liquid is surmounted by the gas along a main axis and the mobile element moves by a rotational movement along a secondary axis, orthogonal to the main axis.

[0037] According to one example, the porous surface covers the entire surface of the at least one plunger element. According to one example, the pores of the porous surface each form a liquid retention cavity. This makes it possible in particular to increase the quantity of liquid retained on the elements having a porous surface, ultimately making it possible to increase evaporation.

[0038] Preferably, the liquid can escape from the cavity only through the inlet through which it entered the cavity. According to one example, the retention pores or cavities are closed, they open outwards but do not communicate with other pores or cavities.

[0039] Preferably, the retention cavities of the porous surface, i.e. the pores, each form a cavity closed towards the inside of the plunger element. Thus, according to this embodiment, liquid which penetrates into the cavity can be retained in the cavity but does not penetrate further into the interior of the plunger element. Thus, the liquid does not pass through the plunger element either from one side to the other or to its center. The liquid remains confined on the porous surface and the retention cavities formed by the pores of the porous surface. Thus, a plunger element formed from a metal mesh or foam does not have retention cavities within the meaning of the invention.

[0040] The liquid retention cavities are open to the outside of the plunger element so that liquid can enter the retention cavity.

[0041] According to one example, the liquid retention cavities formed by the pores of the plunger element have a maximum dimension Dpores such that Dpores <1.5 mm (10-3 meter).

[0042] Preferably, Dpores <1 mm. Preferably Dpores <0.8 mm. Preferably Dpores <0.5 mm. Preferably, Dpores <0.3 mm. With these pore dimensions, the liquid retention surface and therefore evaporation are increased. Furthermore, this does not disrupt the circulation of fluids. Nor does it unnecessarily weigh down the diver by loading it with a quantity of liquid that does not have time to evaporate. The kinetics of the system are therefore improved. Its performance is increased.

[0043] Dpores is the maximum dimension along at least one dimension. Preferably, Dpores is the maximum dimension that the pore opening creates on the surface of the porous surface. If the pores are portions of a sphere, then Dpores is the diameter of the circle formed by the pore opening on the surface of the porous surface.

[0044] According to one example, the engine includes a plurality of plunger elements.

[0045] In one example, the plunger elements are spaced apart from each other so as to create a passage space for the gas in order to optimize the evaporation of the liquid soaked on the porous surface by contact with the gas.

[0046] In one example, the diving elements are equidistant from each other.

[0047] According to one example, at least one plunger element is a rod and / or a cylinder. According to one embodiment, at least one plunger element has a hollow portion.

[0048] In one example, at least one plunger member has at least one opening configured to allow circulation of the liquid or gas mixture as the engine transitions from one of the first configuration and the second configuration to the other of the first configuration and the second configuration.

[0049] Preferably, the plunger member is a hollow tube having side openings.

[0050] In one example, the plunger member or the porous surface of the plunger member is made of wood or a composite material or sponge or fabric.

[0051] In one example, the plunger element or the porous surface of the plunger element is made of oxidized metal.

[0052] In one example, the plunger element or the porous surface of the plunger element is made of a material having a thermal conductivity less than or equal to 10 W ■ m -1 ■ K -1(Watt / (meter *kelvin)).

[0053] According to one example, the plunger element is made of a material having a thermal conductivity strictly less than 10 W ■ m-1 ■ K-1 , preferably less than 8 W ■ m-1 ■ K-1 , preferably less than 5 W ■ m-1 ■ K-1 and preferably less than 3 W ■ m-1 ■ K-1.

[0054] According to one example, the plunger element is made of a material having a thermal conductivity less than or equal to 1 W ■ m-1 ■ K-1 .

[0055] This allows, in particular, not to interfere with the evaporation and condensation process with the gas mixture. Indeed, the evaporation of the liquid would cool a plunger with high thermal conductivity and would cool the heating liquid during its reintegration into the liquid.

[0056] According to one example, the porous surface of the at least one plunger element is made of a material having a thermal conductivity strictly less than 10 W ■ m-1 ■ K-1 , preferably less than 8 W ■ m-1 ■ K-1 , preferably less than 5 W ■ m-1 ■ K-1 and preferably less than 3 W ■ m-1 ■ K-1 . According to one example, the porous surface of the at least one plunger element is made of a material having a thermal conductivity less than or equal to 1 W ■ m-1 ■ K-1 . According to one example, the porous surface of the at least one plunger element is, preferably entirely, made of a porous material and takes the form of at least one of the following typologies: ridges, lamellae, grids, rods, sponges or a lattice. Thus, the porous surface forms a topology. The reliefs forming this topology are formed or are covered by the porous material. The pores are distinct from the reliefs formed by this topology.According to one example, the reliefs forming the typology have a maximum dimension Drelief such that Drelief > 3* Dpores. Preferably, Drelief > 5* Dpores. Preferably, Drelief > 10* D pores.

[0057] For example, Drelief > 1 mm (10-3 meters). For example, Drelief > 2 mm (10-3 meters). For example, Drelief > 5 mm (10-3 meters). For example, Drelief > 10 mm (10-3 meters). Drelief is measured along at least one dimension.

[0058] The presence of these reliefs makes it possible to further increase the developed surface area of ​​the porous surface. This makes it possible to increase the exchange surface to enhance evaporation. This improves the performance of the system.

[0059] In one example, the cavity has a constant volume.

[0060] According to one example, the cavity extends along a main axis between a heating space and a cooling space so that the hot source can heat the liquid in the heating space via the side and / or lower faces and the cold source can cool the gas mixture in the cooling space.

[0061] It is specified that in the context of the present invention, the term differential evaporation engine may be understood as only a constituent portion of the engine. Thus, it may essentially be the enclosure where the movement of the mobile element takes place thanks to the pressure differential created by the hot and cold sources.

[0062] Partial imbibition of a liquid means an action allowing the contact surface of the mobile element with the gas mixture to be imbibed by the liquid and therefore the gripping of the liquid by the mobile element or the depositing of the liquid on the mobile element. In other words, a quantity of liquid is taken from the first configuration to the second configuration.

[0063] The term “moving element” or “displacer” means a part that can move within the enclosure and may include plunger elements.

[0064] The term "plunging element" means solid elements which are integral with the movement of the mobile element.

[0065] It is specified that, in the context of the present invention, the terms “on”, “overcomes”, “covers”, “underlying”, “opposite” and their equivalents do not necessarily mean “in contact with”.

[0066] The terms "substantially", "approximately", "of the order of" mean "within 10%, preferably within 5%" or, when it comes to an angular orientation, "within 10°". Thus, a direction substantially normal to a plane means a direction having an angle of 90±10° with respect to the plane.

[0067] In this patent application, the term mobile corresponds to a rotational movement or a translational movement or to a combination of movements, for example the combination of a rotation and a translation.

[0068] In this patent application, when two parts are indicated as distinct, this means that these parts are separate. They are:

[0069] - positioned at a distance from each other, and / or

[0070] - movable relative to each other and / or - secured to each other by being fixed by added elements, this fixing being removable or not.

[0071] A single piece cannot therefore be made up of two separate pieces.

[0072] In this patent application, the term "integral" used to qualify the connection between two parts means that the two parts are linked / fixed relative to each other, according to all degrees of freedom, unless explicitly specified differently. For example, if it is indicated that two parts are integral in translation in an X direction, this means that the parts can be movable relative to each other except in the X direction. In other words, if one part is moved in the X direction, the other part performs the same movement.

[0073] In the following detailed description, use may be made of terms such as "horizontal", "vertical", "longitudinal", "transverse", "upper", "lower", "top", "bottom", "front", "rear", "inner", "outer". These terms must be interpreted relatively in relation to the normal position of the differential evaporative engine system and the normal direction of travel of the user of the assembly.

[0074] As illustrated in Figures 2A to 4B, there is shown an example of a differential evaporation engine system 1 comprising an enclosure 11 capable of containing a liquid 2 and a gas mixture 3. The liquid 2 and the gas mixture 3 are advantageously distributed so that the gas mixture 3 overcomes the liquid 2 along the main axis Yi. Preferably, the liquid

[0075] 2 extends from the bottom of the enclosure 11 and comprises a surface area 2a in contact with the gas mixture 3.

[0076] The system 1 comprises a hot source 14 configured to heat the liquid 2 present in the heating space. The hot source 14 comprises, for example, a heating element. The system 1 also comprises a cold source 15 configured to cool the gas mixture.

[0077] 3 in a cooling space. The cold source 15 comprises, for example, a cooling element. A cold source may be understood to mean a source for cooling the enclosure 11 from the ambient temperature of the engine. A hot source may be understood to mean a source for heating the enclosure 11 from an ambient temperature of the engine.

[0078] Preferably, the heating element and / or the cooling element belongs to the engine.

[0079] The system comprises a movable element 12 configured to move inside the enclosure 11. For the sake of clarity, the hot source 14 and the cold source 15 have not been shown in the figures.

[0080] According to a first embodiment illustrated in Figures 2A to 3B, the mobile element 12 is configured to move in translation along the main axis Yi. The mobile element 12 preferably comprises a main portion 121 located at the end of a drive shaft 123. According to one example, in the first configuration, the main portion 121 is closer to the heating zone and consequently to the liquid 2. In the second configuration, the main portion 121 is further away from the heating zone and consequently further away from the liquid 2 than in the first configuration. The heating zone being distinct and distant from the cooling zone and the first configuration being different from the second configuration. Preferably, the evaporation of the liquid 2 takes place at the surface area 2a of the liquid in contact with the gas mixture 3. The quantity of liquid 2 evaporated being proportional to said surface area 2a.

[0081] According to one example, in the second configuration said portion of the liquid evaporates entirely upon contact with the gas mixture. According to an alternative example, in the second configuration, said portion of the liquid partially evaporates upon contact with the gas mixture.

[0082] Advantageously, liquid 2 is hot water. The use of water is particularly known for its very high thermal capacity. Other liquids with optimal evaporation capacities relative to their temperature, such as alcohol, may also be used.

[0083] In one example, gas mixture 3 is water vapor. It can also be vapor of other mixtures whose liquid states have evaporation temperatures different from the evaporation temperature of water.

[0084] As illustrated in Figures 2A and 2B and according to a preferred embodiment of the present invention, the movable element 12 comprises at least one plunger element 122. Preferably, the movable element 12 comprises a plurality of plunger elements 122. The plunger elements 122 are configured so as to be at least partially immersed in the liquid 2 in a first configuration shown in Figure 2B and alternatively not immersed or less immersed in the liquid 2 and more in contact with the gas mixture 3 in a second configuration than in the first configuration shown in Figure 2A. According to this embodiment, the plunger elements 122 are configured to move in translation along the main axis Yi

[0085] Preferably, at least one plunger 122 comprises a porous surface 122a configured to impregnate itself with the liquid 2 so as to increase the surface area of ​​liquid 2 in contact with the gas mixture 3 and amplify the evaporation phase. In fact, the efficiency of the system is optimized. Porous surface 122a is understood to mean a surface having hollows, preferably concave, spaced from one another, also called pores or retention cavities. These hollows can thus form a volume relative to the surface 122a of the at least one plunger 122. The volume can then be capable of receiving a liquid allowing the increase of the surface area of ​​liquid 2 in contact with the gas mixture 3. Thus, the liquid does not pass through the plunger element 122 either from one side to the other or to its center. The liquid 2 remains confined on the porous surface 122a and the retention cavities formed by the pores of the porous surface 122a.

[0086] According to one example, the liquid retention cavities formed by the pores of the plunger element 122 have a maximum dimension Dpores such that Dpores <1.5 mm (10-3 meter), preferably Dpores <1 mm, preferably Dpores <0.8 mm, preferably Dpores <0.5 mm, preferably Dpores <0.3 mm. With these pore dimensions, the liquid retention surface and therefore evaporation are increased. Furthermore, this does not disrupt the circulation of fluids. Nor does it unnecessarily weigh down the plunger 122 by loading it with a quantity of liquid 2 that does not have time to evaporate. The kinetics of the system 1 are therefore improved. Its performance is increased. Thus, the pores have a smaller dimension compared to the dimension between two plunger elements 122.

[0087] Dpores is the maximum dimension along at least one dimension, preferably, Dpores is the maximum dimension that the pore opening creates on the surface of the porous surface 122a. If the pores are portions of a sphere, then Dpores corresponds to the diameter of the circle formed by the pore opening on the surface of the porous surface 122a.

[0088] When the displacer 12 moves away from the heating zone, it exposes the plunger elements 122 to the gas mixture so as to promote the evaporation of the liquid 2 soaked on the porous surfaces 122a. By soaking is meant the penetration of the liquid, for example, into the pores present on the porous surfaces 122a of the plungers 122.

[0089] When the displacer 12 moves away from the cooling zone, it exposes the plunger elements 122 to the gas mixture 3 in the cooling zone for the condensation phenomenon. During operation of the engine, the plunger elements 122 are alternately immersed and removed from the liquid 2 while being driven by the movable element 12.

[0090] During the immersion phase which corresponds to the first configuration, the porous surfaces 122a of the immersion elements 122 capture the heat of the liquid 2 called “heating liquid”. The at least one porous surface 122a being immersed in the liquid 2 so as to become impregnated with it.

[0091] During the evaporation phase corresponding to the second configuration, the plunger elements 122 emerge from the liquid 2 so that the at least one porous surface 122a soaked in hot liquid 2 becomes exposed in contact with the gas mixture 3 to allow optimal evaporation.

[0092] Preferably, the plunger elements 122 respectively comprise porous surfaces 122a and the total of these porous surfaces 122a is preferably greater than the surface area 2a of the liquid 2. Thus, all of the porous surfaces 122a are added to the surface area 2a in order to optimize the evaporation of the liquid 2.

[0093] This process can also be reproduced by analogy to increase the condensation of a volume of evaporated liquid 2. In this case, the liquid 2 in which the plunger elements 122 are immersed is cooled.

[0094] As illustrated in Figures 3A and 3B and in the same manner as in the previous embodiment, the movable element 12 comprises plunger elements 122 fixed on the lower face 121a and configured to immerse themselves in the hot liquid 2 in the heating space.

[0095] According to this embodiment, the movable element 12 comprises a rim 124 and an upper face 121 b. The upper face 121 b is preferably a face opposite and parallel to the lower face 121 a. The rim 124 extends from the upper face 121 b so as to define a volume also designated reservoir 121 c capable of containing an additional liquid 4.

[0096] Thus, the system alternates between two configurations:

[0097] - a first configuration illustrated in Figure 3B, in which the plunger elements 122 are immersed in the liquid 2 and the additional plungers 112 are uncovered. In this configuration, the soaked surfaces of the additional plungers 112 uncovered are cold because they have just been immersed in the additional liquid 4 near the cold source. They then transmit negative heat, participating in the condensation of the gas mixture 3. In this configuration, the surfaces of the plunger elements 122 are in the liquid 2 and have no influence on this condensation configuration.

[0098] - A second configuration illustrated in Figure 3A, in which the surfaces of the plunger elements 122 are exposed and the additional plungers 112 are in the additional liquid 4. In this configuration, the surfaces of the plunger elements 122 are soaked with hot liquid and thus transmit evaporation energy. The additional plungers do not influence during this evaporation configuration because they are immersed in the additional liquid 4.

[0099] As illustrated in Figures 4A and 4B and according to one embodiment, the at least one plunger 122 is rotated to alternately pass from the first configuration to the second configuration. The plunger elements 122 having for example a disc shape and advantageously the discs comprise a portion with a porous surface 122a. The porous surface 122a having a surface appearance comprising pores in the same manner as defined previously.

[0100] The discs are mounted on a drive shaft 123 so that they can be rotated in a transverse direction X1. The transverse direction X1 is preferably orthogonal to the main axis Yi.

[0101] Due to the rotary movement of the movable element 12 in the transverse direction Xi, the porous surface 122a is, in a first step, immersed in the liquid 2 and in a second step, the porous surface 122a is soaked in the liquid 2 while being uncovered.

[0102] Thus, the immersion of the discs in the liquid 2 causes the porous surfaces 122a to become imbibed. Said porous surfaces 122a, imbibed and out of the water, are then advantageously stirred by a flow of air so as to accelerate the evaporation phase. This evaporation phase is amplified by the presence of the porous surfaces 122a of the discs which are added to the superficial surface 2a of the liquid 2.

[0103] Thus, evaporation is maintained by rotation of the plunger elements 122 in the liquid 2. The plunger elements 122 are exposed to an air flow. For the condensation phase, the embodiment is identical but with cold water.

[0104] Several optional features of the motor will be described below. All of these optional features are compatible and combinable with each of the embodiments described above, in particular with each of the embodiments in which the plungers are driven in translation or in rotation.

[0105] Preferably, the heat source may be one of the following: an oven, a heat point, a heating resistor, a solar heat source, a recovery heat source, heat from thermal batteries.

[0106] The heat source is advantageously positioned all around and / or below the heating zone so as to allow the most efficient temperature rise possible. The heat source can be obtained by exchanging the working liquid with new hot liquid in a closed circuit so as to maintain the operating pressure. The heat source can also be a coil inside the engine.

[0107] According to one embodiment, the enclosure 11 is a hollow cylinder extending along the main axis Yi and the heating zone is located at a first end of the cylinder along the main axis Yi. The enclosure 11 advantageously extends between a lower enclosure face 11 b and an upper enclosure face 11 a along the main axis Yi. The movable element is guided by its transmission axis.

[0108] Preferably, the heat source is distributed below the hollow cylinder, on the side of the first end and / or on the periphery of the cylinder.

[0109] Preferably, the cold source may be one of the following elements: a refrigeration system, a Peltier module, cooling fins, a radiator.

[0110] The cold source is advantageously positioned all around the cooling zone so as to allow the most efficient temperature drop possible. The cold source can be a flow of cold liquid inside the engine coming from outside and maintained at the operating pressure in a closed circuit.

[0111] According to one embodiment, the enclosure 11 is a hollow cylinder extending along the main axis Yi and the cooling zone is located at a second end of the cylinder along the main axis Yi.

[0112] Preferably, the cold source is distributed above the hollow cylinder, on the side of the second end and / or on the periphery of the cylinder.

[0113] The porous surface 122a is configured to retain liquid when the at least one plunger is immersed. This porous surface thus forms liquid retention cavities or pores as defined above.

[0114] The porous surface 122a may be formed by the external material of the at least one plunger element 122. This material may be porous. A porous material may thus be understood as having pores as defined above. It may for example be materials such as wood, oxidized metal, paper, fabric, porous composite materials or a spongy material. Thus, the plunger element 122 may for example comprise a non-porous body and a coating, covering the body and forming the porous surface 122a. The thickness of the body is for example 3 times, or even 5, or even 10 times greater than that of the porous surface 122a.

[0115] Alternatively, the porous surface may be formed by reliefs present on the plunger element. These reliefs may be formed, for example, by: ridges, grooves, lamellae, grids, rods, or a lattice. For example, the grooves or ridges may extend in a direction parallel to the main axis Yi perpendicular to the translation direction if the movable element is translational or along radii of the disk if the movable element 12 is rotary. It will be noted that the presence of reliefs may be combined with the use of a porous material.

[0116] According to one example, the porous surface of the at least one plunger element is made entirely of a porous material and takes the form of at least one of the following typologies: ridges, lamellae, grids, rods, sponges or a lattice. The reliefs forming the typology have a maximum dimension Drelief such that Drelief > 3* Dpores, preferably, Drelief > 5* Dpores, preferably, Drelief > 10* Dpores. According to one example, Drelief > 1 mm (10-3 meters). According to one example, Drelief > 2 mm (10-3 meters). According to one example, Drelief > 5 mm (10-3 meters). According to one example, Drelief > 10 mm (10-3 meters). Drelief is measured along at least one dimension. The presence of these reliefs makes it possible to further increase the developed surface area of ​​the porous surface 122a. This increases the exchange surface to enhance evaporation. This improves the performance of the system 1.

[0117] This type of typology makes it possible to generate a set of voids capable of filling with fluid.

[0118] Wood can be used. Wood is naturally porous because its fiber structure has voids with a spongy capacity. Wood is ideal for absorbing fluid and is an unexpected material for an engine. Wood has the advantage of being an excellent thermal insulator, which is ideal for good engine performance.

[0119] The formal typology of the plunger elements is such that it allows the soaked surface area from which the liquid is taken to be increased while maintaining the same cavity volume.

[0120] A porous material or a porous surface may be understood as a solid material comprising a plurality of cavities capable of filling with fluid.

[0121] According to one example, the engine comprises a plurality of plunger elements 122. These may be cylindrical tubes, preferably solid and alternately hollow. The plunger elements 122 may be spaced apart so as to create a space for the passage of the gas mixture flow.

[0122] The plunger elements are advantageously rods whose diameter is less than or equal to the diameter of the displacer. Preferably, the diameter of a plunger element 122 is at least two times smaller, preferably at least four times smaller than the outside diameter of the movable element 12. According to the main axis Y1, preferably the plunger elements will be sized according to the material which composes them so that the operating conditions of the engine do not cause them to bend.

[0123] According to one example, the plunger elements are hollow and preferably have openings to allow easy evacuation of the liquid 2.

[0124] According to one example, the plunger element 122 comprises a porous surface 122a. The plunger element 122 may be entirely covered with the porous surface 122a. The plunger element 122 may be covered with a fabric. The porous surface 122a may be made of one of the following materials: oxidized metal, wood, a composite material having cavities. Thus making it possible to increase the exchange surface to enhance evaporation. This makes it possible to improve the performance of the system 1.

[0125] Advantageously, the plunger element may be made of natural or synthetic sponge or a similar material having a high capacity for absorbing liquids.

[0126] Preferably, the plunger element has a thermal conductivity less than or equal to 226 W ■ nr 1 ■ K, preferably a thermal conductivity less than or equal to 100 W ■ m -1 ■ K -1 preferably less than or equal to 10 W ■ nrr1 ■ K -1 , preferably less than or equal to 1 W ■ m -1 ■ K -1 . Preferably, the plunger element, or at least the material forming the porous surface, has a thermal conductivity of less than 10 W ■ nrr 1 ■ K -1 , preferably less than 8 W ■ m -1 ■ K -1 , preferably less than 5 W ■ m -1 K -1 , preferably less than 1 W ■ m -1 ■ K -1 . Thus, the plunger elements do not have the function of conducting heat. The plunger element 122 advantageously has a thermal conductivity less than or equal to 10 W ■ m -1 ■ K- 1so as not to disturb the evaporation and condensation phases with the gas mixture. The evaporation of the liquid would cool a plunger element 122 having a high thermal conductivity and would cool the heating liquid 2 when it is reintegrated into the liquid 2. Preferably, the plunger element 122, at least the material forming the porous surface, may be made of wood. Thus, the plunger element 122 may be entirely made of wood, that is to say that the only material in its thickness is wood. Alternatively, it may be made of a first material covered with wood. Thus, the plunger element 122 may have a thermal conductivity of between 0.035 and 0.049 W ■ nr 1 ■ K -1 . Thus, a plunger element 122 is obtained having a porous material and minimized thermal conductivity allowing better evaporation of the liquid 2.

[0127] According to a particular embodiment, the plunger elements 122 are small identical elementary volumes.

[0128] According to a particular embodiment, the movable element 12 and the plunger elements 122 form a single monolithic part.

[0129] According to a particular embodiment, the movable element 12 is configured so as to alternately pass the gas from the heating space to the cooling space.

[0130] The invention is not limited to the embodiments previously described and extends to all embodiments covered by the claims.

[0131] Digital references

[0132] 1 / Differential evaporation engine system 11 / enclosure

[0133] 11 a / upper enclosure face

[0134] 11 b / lower enclosure face

[0135] 112 / additional plunger elements

[0136] 12 / mobile element

[0137] 121 a / lower surface

[0138] 121 b / upper surface

[0139] 122 / plunger element

[0140] 122a / porous surface

[0141] 123 / drive shaft

[0142] 124 / ledge

[0143] 14 / hot spring

[0144] 15 / cold source

[0145] 2 / liquid

[0146] 2a / surface area

[0147] 3 / gas mixture

[0148] 4 / additional liquid

[0149] Yi / Main axis

[0150] Xi / Transverse axis

Claims

Claims Differential evaporation engine system (1) comprising: - an enclosure (11) having a cavity capable of containing a liquid (2) and a gas mixture (3), - a hot source (14) configured to heat the liquid (2), - a cold source (15) configured to cool the gas mixture (3), - a movable element (12) configured to move inside the enclosure (11), the movable element (12) comprising at least one plunger element (122), the plunger element (122) being configured so as to be at least partially immersed in the liquid (2) in a first configuration and alternately in contact with the gas mixture (3) in a second configuration, the second configuration being different from the first configuration, in the second configuration, the plunger element (122) being not immersed in the liquid (2) or being less immersed in the liquid (2) than in the first configuration, the system (1) being characterized in that the at least one plunger element (122) has a porous surface (122a), the plunger element (122) being configured so that, in the first configuration, the porous surface (122a) is impregnated with a portion of the liquid (2) and that, in the second configuration,said portion of the liquid (2) evaporates at least partially upon contact with the gas mixture (3). System (1) according to the preceding claim wherein the enclosure is configured so that the liquid is surmounted by the gas along a main axis (Yi) and the movable element (12) moves by a translational movement along the main axis (Yi). System (1) according to the preceding claim wherein the plunger element (123) extends mainly in a direction parallel to the main axis Yi. System (1) according to any one of the preceding claims wherein the movable element (12) comprises a main portion (121) having a lower surface (121a) normal to the main axis (Yi) and the at least one plunger element (122) extends from the lower surface (121a),preferably the plunger element (122) having a rod shape. System (1) according to any one of the preceding claims wherein the enclosure (11) comprises at least one additional plunger element (112) fixed relative to the enclosure (11) and having an additional porous surface portion (112a), the at least one additional plunger element (112) extending into the enclosure from a lower enclosure face (11b) of the enclosure (11) in a direction parallel to the main axis (Yi). System (1) according to any one of the preceding claims wherein the main portion (121) of the movable element (12) defines a reservoir (121c) configured to contain an additional liquid (4) and the motor (1) is configured so that in the second configuration, the at least one additional plunger element (112) soaks up the, additional liquid (4). System (1) according to any one of the preceding claims comprising a plurality of additional plunger elements (112). System (1) according to claim 1 wherein the enclosure (11) is configured so that the liquid is surmounted by the gas along a main axis (Yi) and the movable element (12) moves by a rotational movement along a secondary axis (Xi), orthogonal to the main axis (Yi). System (1) according to any one of the preceding claims wherein the porous surface (122a) covers the entire surface of the at least one plunger element (122). System (1) according to any one of the preceding claims wherein the motor comprises a plurality of plunger elements (122).System (1) according to the preceding claim in which the plunger elements (122) are spaced apart from each other so as to create a passage space for the gas in order to optimize the evaporation of the liquid soaked on the porous surface (122a) by contact with the gas. System (1) according to the preceding claim in which the plunger elements are equidistant from each other. System (1) according to any one of the preceding claims in which at least one plunger element (122) is a rod and / or a cylinder. System (1) according to any one of the preceding claims in which the plunger element (122) has a hollow portion.System (1) according to any one of the preceding claims wherein at least one plunger element (122) has at least one opening configured to allow circulation of the gas mixture (3) during passage of the system (1) from one of the first configuration and the second configuration to the other of the first configuration and the second configuration. System (1) according to any one of the preceding claims wherein the plunger element (122) or the porous surface (122a) of the plunger element (122) is made of wood or a composite material or sponge or a fabric. System (1) according to any one of the preceding claims wherein the plunger element (122) or the porous surface (122a) of the plunger element (122) is made of oxidized metal.System (1) according to any one of the preceding claims in which the plunger element (122) is made of a material having a thermal conductivity less than or equal to 10 W ■ m. -1 ■ K -1 and preferably less than or equal to 1 W ■ m -1 ■ K- 1 System (1) according to any one of the preceding claims wherein the porous surface of the at least one plunger element (122) is entirely made of a porous material and takes the form of at least one of the following typologies of ridges, lamellae, grids, sticks, sponges or a lattice. System (1) according to any one of the preceding claims in which the cavity has a constant volume. System (1) according to any one of the preceding claims in which the cavity extends along a main axis (Yi) between a heating space and a cooling space so that the hot source (14) can heat the liquid (2) in the heating space via the lateral and / or lower faces and the cold source can cool the gas mixture (3) in the cooling space.

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