WO2014191689A1

WO2014191689A1 - Device for converting thermal energy into mechanical energy and facility comprising such a device

Info

Publication number: WO2014191689A1
Application number: PCT/FR2014/051269
Authority: WO
Inventors: Claude FAVY
Original assignee: Storewatt
Priority date: 2013-05-30
Filing date: 2014-05-28
Publication date: 2014-12-04
Also published as: FR3006370A1; FR3006370B1

Abstract

A device for converting thermal energy into mechanical energy. A device for converting, into mechanical energy, the thermal energy contained in a first so-called hot liquid of a heat source and a second so-called cold liquid of a cold source, the device comprising at least one enclosure (1) inside which an energy recovery process takes place, the device comprising a so-called support surface (14) extending at least partially into a collection area (31) of the enclosure, the support surface (14) being inclined relative to the vertical direction (A) and directed upwards, the liquid forming a layer (13) of monophasic liquid flowing on the support surface (14) at increasing speed.

Description

DEVICE FOR CONVERTING THERMAL ENERGY IN MECHANICAL ENERGY AND INSTALLATION COMPRISING SUCH A DEVICE

The present invention relates to a device for converting thermal energy into mechanical energy. It applies to the conversion of thermal energy between a hot source and a cold source with a small difference in temperature and more particularly to the thermal energy of the seas.

The conversion of thermal energy between a hot source at a moderate temperature and a cold source with a small difference in temperature into mechanical energy has long been an important issue.

There are numerous configurations for such energy conversion and can be mentioned as examples:

• low temperature geothermal energy;

• industrial heat discharges at low temperatures;

• the thermal energy of the seas (ETM) is the temperature difference between the surface layers and the deep layers of the oceans, which reaches nearly 20 ° C in the intertropical zones.

Many devices for converting this thermal energy into mechanical energy have been proposed, but the industrial applications are still very few considering in particular the following points:

The very small differences in temperature between the hot source and the cold source imply a theoretical maximum rate of conversion of the thermal energy into very low mechanical energy (of the order of 7% for ΙΈΤΜ);

• the effectiveness of the proposed devices remains very limited, which further reduces this conversion rate;

• As a result, the volumes of fluid to be treated are extremely important requiring very large heat exchange devices;

• constraints related to the marine environment.

The solutions proposed in the prior art can be divided as follows:

Solutions that use an organic Rankine cycle, ie in which the hot fluid from the hot source transfers its heat to a working fluid through an exchanger to vaporize it. The working fluid expands through a turbine providing mechanical work and is then condensed in a condenser by exchanging with the cold fluid of the cold source to be finally pressurized by a pump. This so-called closed cycle has the advantage of allowing the use of a working fluid having high densities of vapor at the temperatures considered and therefore of turbines of reasonable dimensions. However, it has major drawbacks, including the very large size of the heat exchangers between the hot and cold sources and the working fluid to be able to handle very high flow rates with a minimum temperature nip. The risks of "biofouling" of these exchangers in the case of ΙΈΤΜ are very important and the need to use working fluids such as ammonia also has real impacts on the environment. • Solutions in which the hot fluid (usually water) is vaporized partly through its own specific heat (this phenomenon is known as flash vaporization), its vapor relaxed in a turbine where it provides a job mechanical, the steam being subsequently condensed through the heat exchange (usually direct) with the fluid from the cold source (usually water). This so-called open cycle solution has the advantage of avoiding the use of oversized heat exchangers between two different fluids. However, it has major limitations especially in the case of ΙΈΤΜ. Indeed, in this case, the temperature of the hot source (approximately 28 ° C) corresponds to extremely low vapor pressures of the order of three hundredths of a bar. At this pressure, the density of the steam is very low and it is therefore necessary to pass through the turbine an extremely high volume flow which implies both very high rotor diameters and high peripheral speeds. The centrifugal forces on the elements of the turbine then become too important for powers from a few MW. In addition the inertia of the turbine also becomes very important which can generate problems of coupling to the electrical network. This open cycle is therefore less and less considered for powers greater than a few MW.

• Solutions using so-called diphasic turbines. To date, no device of this type has proved its effectiveness, particularly in the field of very small temperature differences between the hot source and the cold source.

• Solutions in which the hot water undergoes a flash vaporization, its vapor then being relaxed in a vertical divergence where it communicates part of its energy to liquid water so as to raise this water in the device by fighting against the gravity. The energy is then recovered by simple hydraulic turbining of the liquid phase before elevation. These latter solutions make it possible to avoid the heat exchangers of the closed cycles and the oversized turbines of the open cycles mentioned above. The proposed solutions are:

1. in the form of bubbles, as described for example in US Pat. No. 3,967,449, in which steam bubbles are produced in the liquid phase so as to reduce the density of the assembly. This device has great difficulty in maintaining the pressure conditions necessary for the formation of bubbles in the liquid phase.

2. As a foam, as described for example in US 4,249,383, wherein a foam composed of steam, hot water and a foaming agent is formed and raised by steam. The need to use a foaming agent and the difficulty in maintaining the stability of the foam seem unacceptable.

3. in the form of drops, as described for example in US 4,221,657 and US 4,441,321 (inventor Stuart L. Ridgway) in which microdroplets are raised by their own steam in a vertical chamber (this process is known as "mistlift").

The term "m istlift" will hereafter refer to a process by which drops of hot fluid are raised against gravity by their own vapor as a result of the difference in vapor pressure between the bottom hot portion and the top portion. cold device, it being understood that the terms "hot" and "cold" will be included here relatively to each other, being "hot" which is at a temperature above what is "cold". Although simple, the device proposed in the state of the art has a number of disadvantages.

For example, it is necessary to set up a steam passage section very large given the very low density of steam and its initial speed necessarily limited, associated with a very large height. For example, such a device of 4 MW (Mega Watts) for ΙΈΤΜ would be 20m (meters) in diameter for nearly 100m high involving considerable difficulties of implementation, operation and cost.

In addition, the collision of microdroplets with the walls or between them, given the very great vertical distance to travel, involves significant energy losses.

The droplets of hot water must also be captured by a spray of cold water droplets with which they coalesce. We can question the effectiveness of this capture of drops of hot water by drops of cold water and energy losses during each collision on the course of this set of drops. Indeed, the drops of cold water are sent in the form of spray so as to concentrate the resulting stream to the upper part. Even with the additional kinetic energy provided by the shocks with the hot drops, the horizontal component of their speed compared with its vertical component, given the gravity, will be important in the upper part of the device making the final concentration phase of the jet difficult. .

Finally, we can question the stability of the cold water spray in its upward movement, subjected to the shock of hot water droplets and to merge into a single vertical component jet especially as the device can be floating on the sea and therefore subject to the many movements due to the influence of winds, currents and waves and that the respective temperatures of hot and cold water can vary resulting in different kinetic energy transfers and therefore geometries of different jets.

The patent application US 2013/0031 903 tries to solve these problems by repeating the method described in the document US 4,441,321 and making the following proposals:

• The process is reproduced in a plurality of adjacent vertical cells allowing a greater heat exchange surface between vapor to be condensed and cold water.

• Different configurations of the cold water spray are proposed with for each of them a direction of the cold water spray upward and close to the vertical forming a spray turning into a free jet, namely that the possible bearing surfaces are located above the jet and therefore can not be a support surface relative to gravity. The cold water spray remaining free, its geometric characteristics may vary depending on the temperatures of hot and cold water and possible movements of the device and other instabilities.

In order to take these variations into account, it is proposed an improved jet recovery system that can vary depending on the geometric characteristics of the jet. It is also proposed to vary the injection conditions of the cold water jet for better adaptation.

In the devices of the prior art using a mistlift process and especially in the documents cited above, hot water droplets animated by an ascending speed and accelerated by their own steam strike a cold water spray ascending which they communicate a part of their kinetic energy and, under the effect of multiple coalescences, the set of drops is transformed into a single liquid jet. The cold water spray has the dual function of achieving the condensation of steam (hence the need for a spray to obtain sufficient heat exchange surfaces) and, by multiple collisions between droplets, to become a liquid jet unique. As is explained in more detail in the description of FIGS. 1, 3, 4 and 5, illustrating the state of the art, the transfer of energy, the transformation into a single jet and its capture pose significant problems.

The device according to the invention, while retaining the principle of mistlift process, that is to say water droplets driven upwards against gravity by their own steam, provides an answer to the difficulties related to devices that have been proposed in the prior art, and in particular:

• It limits the volume of the device through the possibility of choosing higher initial steam speeds while maintaining a reduced height;

• collisions of hot microdroplets with the walls or between them are limited;

• there are few collisions between droplets of hot water and droplets of cold water;

The device makes it possible to fuse and transmit the kinetic energy of the hot water droplets with a stable and well-established liquid monophasic flow which ensures the minimum of energy losses to the device;

• The device is insensitive to platform movements in the case of a floating device and allows a simple adjustment of its operation when the cold fluid and hot fluid temperatures vary;

• its construction is simple, based on inexpensive materials and without significant precision constraints;

• It does not use any fluid presenting risks for the environment in particular in the case where the fluid of the hot and cold springs is water.

In the following text, the terms "very small droplets" where

"Droplets" or "microdroplets" denote drops of liquid diameter from about ten microns to a few millimeters.

The term "fog" refers to a cluster of droplets (several millions to billions per cubic meter) dispersed in the vapor generated by their own partial evaporation.

According to a first object, the invention proposes a device for converting into mechanical energy the thermal energy contained in a first so-called hot liquid from a hot source and a second so-called cold liquid from a cold source, the temperature of the hot liquid. being greater than the temperature of the cold liquid, the device comprising at least:

an enclosure delimited by a lateral wall resistant to external pressure, the enclosure being maintained at an internal pressure lower than the external pressure, the enclosure comprising, in a vertical direction from the bottom upwards, a lower part, a zone generating and fogging acceleration, a pickup area, extending over the fog generation and acceleration area, and an upper portion;

means for feeding the hot liquid into the lower part of the enclosure; a generator and fog accelerator assembly in the fog generation and accelerating zone, for generating from the hot liquid a mist formed of hot liquid droplets dispersed in the vapor formed by their own partial evaporation and accelerating by detente this two-phase fluid at an ascending speed, that is to say comprising at least one component in the vertical direction directed towards the upper part of the enclosure; condensing means in the collection zone for condensing the produced vapor by cooling with the cold liquid;

means for supplying the cold liquid into the collection zone supplying the condensation means;

means for collecting the liquid forming the liquid layer in the upper part of the enclosure;

evacuation means in the upper part of the enclosure allowing the evacuation of all or part of the liquid from the enclosure;

energy recovery means for generating mechanical energy by liquid turbines.

The device comprises at least one so-called support surface extending at least partially in the capture zone, the support surface being inclined at an angle of between 0 and 20 ° with respect to the vertical direction and having a normal whose component parallel to the vertical direction is directed towards the upper part of the enclosure, the hot water droplets accelerated out of the zone of generation and fog acceleration of the enclosure to integrate by communicating all or part of their kinetic energy in a liquid layer formed by at least the coalescence of the hot water droplets on the support surface, the layer of liquid flowing on the support surface with an ascending speed.

The sheet of liquid is then supported by the support wall, limiting the influence of gravity on the sheet of liquid and facilitating its upward movement. The cycle of transformation of thermal energy into mechanical energy in the enclosure is notably more robust and less sensitive to variations in environmental conditions.

According to one embodiment, the device may furthermore comprise non-condensed evacuation means in the upper part of the enclosure allowing evacuation of the non-condensable gases and the fraction of vapor that would not have been condensed. between the lower part and the upper part of the enclosure.

The device may further comprise liquid injection means on the support surface, in order to contribute to the formation of the liquid layer on the support wall and for capturing the droplets of the fog moving in the enclosure.

The liquid injection means for forming the liquid layer comprise for example at least one liquid injection nozzle positioned in the chamber to form the layer of liquid flowing on the support surface with an initial upward velocity.

The injection means for forming the sheet of liquid may be able to be connected to a source of cold liquid outside the device, or to a source of hot liquid outside the device. device or be connected to the upper part of the enclosure, so that they are fed by the recirculation of at least a portion of the liquid collection means.

According to one embodiment, the condensation means comprise at least one spray nozzle for projecting into the chamber a spray of cold liquid animated with an ascending speed, substantially parallel to the wall, so that the sheet of liquid is between the first cold liquid spray and the support surface.

Alternatively, the condensation means comprise at least one spray nozzle for projecting a spray of cold water animated with an ascending speed and substantially parallel to the flow of droplets along a surface opposite to the support surface inside the enclosure.

The device may comprise means for controlling and controlling the energy recovery means taking into account the conditions prevailing in the enclosure.

The energy recovery means comprise for example at least one reversible turbine which can be used as a pump.

According to one embodiment, the energy recovery means are associated with the means for feeding the liquid to the injection means of the liquid layer and / or to the means for supplying the hot liquid and / or to the means for supplying the liquid. evacuation of the liquid.

The device may comprise means for flotation in water, so that it can be installed for example directly in an area such as an ocean or a lake.

According to a second aspect, the invention proposes an installation for converting into mechanical energy of thermal energy comprising a hot source and a cold source, the installation further comprising a device as presented above and in which the hot source is water on the surface of a body of water, the means for supplying the hot liquid being in fluid connection with the hot source, and the cold source is water at depth of the same body of water , the means for supplying the cold liquid being in fluid connection with the cold source.

The body of water is for example an ocean.

The figures of the drawings are now briefly described.

Fig. 1 is a diagram showing the mistlift device among the prior art as disclosed in US 4,441,321.

Figure 2 is a diagram showing a top view of a honeycomb device of the prior art, as proposed in US 2013/0031903.

Fig. 3 is a diagram showing a vertical sectional view of a honeycomb cell using a cold water convergent spray from the prior art as proposed in US 2013/0031903.

Fig. 4 is a diagram showing a vertical sectional view of a honeycomb cell using a cold water divergent spray of the prior art, as proposed in US 2013/0031903.

Fig. 5 is a diagram showing a vertical sectional view of a honeycomb cell using a combination of cold water convergent and divergent sprays among the prior art, as proposed in US 2013/0031903. FIG. 6 represents a schematic diagram seen in vertical section of a first embodiment of an enclosure of a device according to the present invention.

FIG. 7 represents a detailed view of FIG. 6, illustrating an embodiment of the zone around one or more nozzles for injecting a liquid layer and a spray of cold water.

FIG. 8 represents a second embodiment of the enclosure of FIG. 6 in which the water of the liquid layer comes from a partial recirculation of the water supplying an upper collector.

FIG. 9 represents a third embodiment of the enclosure of FIG. 6 in which the water of the liquid layer comes from hot water in the immediate vicinity of the device.

FIG. 10 represents a first embodiment of a complete device composed of several enclosures of FIGS. 6 to 9 in a floating configuration in vertical section.

FIG. 11 represents in section view from above the device represented in FIG.

FIG. 12 represents a schematic diagram seen in vertical section of a second embodiment of the device of the present invention, in the form of a cone of revolution.

Figure 13 shows a schematic diagram seen in vertical section of a fifth embodiment of an enclosure component of the device of the present invention and comprising a plurality of support surfaces.

The devices represented in the various figures are adapted for ΙΈΤΜ, namely that the hot liquid designated hot water here is seawater extracted surface at a temperature that can generally vary between 20 and 30 ° C (degrees Celsius) and the cold liquid designated by cold water is seawater extracted from the depths (generally between 500 and 1500m deep) and at a temperature of between approximately 5 and 10 °, conditions which are found especially in the oceans. intertropical zones.

The devices described could of course operate in a different context than ΙΈΤΜ with hot and cold fluids different from seawater, for example with geothermal energy and hot water coming from underground and cold water coming from a river, or with industrial heat recovery, or at temperatures substantially different from those indicated above with the condition of adaptations to the device obvious to a specialist.

It will now be presented the state of the art as illustrated in Figures 1 to 5.

Figure 1 shows the process described in US 4,441,321.

The device comprises a chamber 102, or enclosure, extending in the vertical direction. The vertical direction is taken here with reference to gravity. Therefore, the terms "above", "on", etc., "below", "under", etc. and "high", "low", etc. "Lower", "higher", etc. will be taken with reference to the natural orientation of the figures, which is vertical.

Hot water 101 taken at the surface 100 of an ocean is injected into the enclosure, at the bottom, with an ascending vertical speed by a device 104 generating fog in a lower part of an enclosure 102 making it possible to produce a a multitude of microdroplets inside the enclosure 102 where a high vacuum is maintained.

Microdroplets, under the effect of vacuum, partially vaporize (flash vaporization). The vapor is then relaxed in an area of the enclosure 102 in which the walls of the enclosure 102 apart, forming a vertical divergence 108, in which the steam communicates part of its energy to the hot water microdroplets by raising them against gravity.

Cold water pumped from the depths is injected into the chamber 102, along the walls, halfway up the chamber 102, above the vertical divergent 108, in the form of a spray 106 with an initial upward velocity. This spray 106 is itself driven upwards, in an upper part of the enclosure 102, by the assembly formed by the droplets of hot water and steam.

This spray 106 of cold water gradually condenses the steam in the upper part of the enclosure.

The assembly formed by the cold water spray 106, the hot water droplets and the remaining vapor converge at the top of the enclosure to form a liquid jet. The liquid part is released into the ocean.

A vacuum pump 12 to evacuate the non-condensable out of the enclosure 102.

The energy of the device is recovered by means of a hydraulic turbine 1 16 inserted into the feed channel of the hot water 101.

Although simple, this device has the disadvantage of requiring very large steam passage sections (given the very low density of the steam and its initial speed necessarily limited, the pressure upstream of the fog generator being diminished by the pressure drop due to the hydraulic turbine) associated with very high enclosure heights 102. For example, such a device of 4 MW for ΙΈΤΜ would be 20m in diameter for nearly 1 00m high.

The droplets will therefore have to travel from the lower part of the enclosure 102 to the upper part this long distance with a very high probability of collision between the droplets or with the walls of the enclosure 102. In fact, although homogeneous Initially, the dimensions and speeds of the droplets become increasingly heterogeneous as collisions and coalescence phenomena, resulting in different droplet speeds.

Each collision is a loss of energy for the device, ultimately resulting in a significant loss of energy. The largest droplets will be little or no steam and may fall back into the chamber. The convergence of the droplets to form a single jet can not be done without a significant loss of energy. In addition, the contact surface between the spray 106 of cold water and the steam must be very important, requiring a fine atomization of the cold water spray to obtain the heat exchange necessary for a total condensation of steam by water cold. Under these conditions, the collisions of the droplets composing the cold water spray and the droplets of hot water then transforming into a single liquid jet should consume a lot of energy during successive collisions.

It is also important to mention the stability problems of cold water spray 106. It is indeed a free spray, not leaning and being guided against the effect of gravity by any wall. It will therefore necessarily tend to move away from the wall of the enclosure 1 02 under the effect of gravity. It is unlikely that collisions with the hot water droplets will keep the cold spray 106 pressed against the wall. The cold spray 106 will therefore be unstable and subject to the energetic conditions of the system (for example, to variations in cold water or hot water temperatures). making his geometry unstable and his capture random. Its geometry will be particularly disturbed and random at the top of the device. In the same way, in the case of a floating device, the movements of the assembly will necessarily disturb the geometry of the cold water jet.

Figures 2, 3, 4 and 5 show the device proposed in US 2013/0031903. The device proposed in this document is based on the mistlift process by proposing variants in particular to solve the problems related to the disturbances of the cold water spray.

FIG. 2 represents a top view of a plurality of cells 202, or enclosures, each being delimited by a wall 206. The enclosures 202 are arranged vertically and adjacent, and are grouped together in a platform 200, and in each of which the mistlift process is reproduced. The main advantage of this configuration is to allow a greater heat exchange surface between steam to condense and cold water. Optionally, the speakers 208 in the center of the platform 208 are dedicated to the supply of cold water.

Different configurations of cold water spray to improve its stability are proposed in Figures 3, 4 and 5.

In Figure 3, there is illustrated a column 300, defining a vacuum chamber 308, wherein a mist, a mixture of droplets and steam, is created in the lower part by a generator 306 fog. As in US 4,441,321, the steam moves up the column. It is first relaxed in a divergent 310. Cold water 312 is injected at a point

314 injector placed after the divergent 31 0 and forms a convergent conical envelope in a zone 316 of condensation, towards the top of the column 300 and surrounding the rising mist of droplets. The condensed water is recovered as a jet at the top of the column 30 by a recovery system 318.

In FIG. 4, the column 600 comprises a central conduit 604. The cold water is fed to a point 606 of injection, and forms a conical cold water spray, diverging upwards, surrounded by the mist 602 from the generator 608 fog. The cold water spray provides a heat exchange surface 614 with the droplets of the mist 602. The condensed water is recovered in a basin 618 at the top of the column 600.

FIG. 5 shows a column 650 combining the two configurations of the cold water spray of FIGS. 3 and 4, with a cold central duct 654, and forming a cone in the condensation zone surrounded by a mist 656, a spray 652 annular cold water surrounding fog

656 being further injected into the condensation zone.

In each of the proposed configurations, the cold water spray forms a free spray that is to say that it is not guided relative to the gravity forces by any bearing surface, the potential bearing surfaces lying at the top cold water spray.

The set comprising the cold water spray and the hot water droplets is transformed into a single jet (by successive coalescences) at the top of the enclosure.

The remaining free spray, its geometry and in particular its trajectory can vary according to the kinetic energy transmitted by the droplets of hot water (itself dependent on the temperatures of the hot and cold water and the conditions of spraying hot water) and possible movements of the whole device when it is floating as well as other dynamic instabilities.

The recovery of the jet at the top of the enclosure becomes difficult. It must be noted that the jet recovery system must intervene when its upward speed is minimum in order to minimize energy losses of the system. The jet is, in the upper zone of the enclosure, at low speed, the influence of gravity on its direction relative to the vertical becomes very sensitive because the jet is free.

In order to take these variations into account, the document US 2013/0031903 proposes, in the upper part of the enclosure, an improved condensed water jet recovery system which may vary according to the geometric characteristics of the jet. It is also proposed to vary the injection conditions of the cold water spray in speed and direction for better adaptation in real time to the conditions given by sensors, including the position of the platform.

These adaptations meet only partially the difficulties described above and inherent to the device described in US Patent 4,441,321. In addition, they are extremely complex to implement.

Several embodiments of the thermal energy mechanical energy conversion device according to the invention will now be described with reference to FIGS. 6 to 13. More specifically, FIGS. 6 to 13 show an installation comprising the device floating in an expanse of water, for example an ocean. In general, the drawings are purely schematic and serve the purpose of helping to understand the device. To facilitate the understanding of the device, scales and angles are not preserved. The device is presented in an ETM configuration. Although the installation comprising a floating device has many advantages, the installation can include the device in any other configuration, on land, laid and semi-immersed or any other configuration compatible with its operation.

The device is placed in an environment comprising a so-called hot source and a so-called cold source. The hot source contains a hot fluid, and the cold source contains a cold fluid. The terms "hot" and "cold" will be included here relative to each other, the hot liquid being at a temperature higher than the cold liquid. In the examples presented here, the device being immersed at least partially in the water of an ocean 37, the hot source is constituted by the water 28 of the ocean near the surface 22 of the ocean 37, which is at a temperature higher than that of the water located at depth, and constituting the cold source. Therefore, in the following example, the hot fluid is hot water from the ocean and the cold fluid is cold water from the ocean. However, it can be provided that the hot source and the cold source are constituted by other means.

FIG. 6 represents a schematic view in vertical section of an enclosure 1 according to a first embodiment, making it possible to understand the operation of the device proposed in the present invention application. FIG. 6 does not represent the whole of the floating device according to the present invention but only a schematic diagram making it possible to understand its operation, the conditions necessary for its flotation in good conditions not being taken into account in this figure. The means for supplying hot water and cold water are not shown in the figures. The device comprises at least one enclosure 1, in practice a plurality of enclosures 1 as will be explained later, delimited by a side wall 7. Means, not shown, are implemented to maintain a partial vacuum inside the chamber 1, so that the pressure inside the chamber 1 is less than the external pressure. The characteristics of the lateral wall 7 enable it to withstand the pressure difference between the inside and the outside of the enclosure 1.

The enclosure 1 extends, in a vertical direction A, from a lower portion 8 to an upper portion 9.

As for the presentation of the state of the art and Figures 1 to 5, the vertical direction A is taken here with reference to gravity, when the device is installed. Thus, the vertical direction A is substantially coincident with the direction of gravity. In addition, for purposes of simplification, in the following, the terms "above", "on", "below", "below", etc. "Lower", "higher", etc. should be understood with reference to the vertical direction A and the natural orientation of the figures, it being understood that in the figures, the lower part 8 is located under the upper part 9.

Thus, the adjective "vertical" will be used in what follows to designate what is parallel to the vertical direction A, and the adjective "horizontal" will be used to designate what is perpendicular to the vertical direction A.

The lower part 8 and the lower part 9 are not necessarily aligned in the vertical direction A. For example, and as is the case in the figures, the enclosure 1 extends in a general direction inclined with respect to the vertical direction A. Between the lower part 8 and the upper part 9, the chamber 1 comprises a so-called fog generation and acceleration zone 30 extending from the lower part 8 and a so-called capture zone 31, extending from zone 30 for generating and accelerating fog up to the upper part 9.

The device comprises at least one means for supplying hot water into the lower part of the enclosure, in fluid connection with a hot water source. For example, hot water is collected in the upper part of the ocean 37 near the surface 22, and is fed through a supply pipe 2, in fluid connection with the hot source, in the lower part. of the enclosure 1. Optionally, a pump can be set up to pump hot water. The hot water may be filtered beforehand and a first degassing of the non-condensable gases at the temperatures envisaged may be carried out before it is introduced into the chamber 1 via the hot water supply pipe.

The device comprises in the embodiment shown a fog generator 4 placed in the chamber 1, in a lower part of the zone 30 for generating and accelerating fog, the generator 4 being preceded, in the direction of circulation of the hot water 28 from the supply pipe 2, a distributor 3 in the lower part 8.

The term "fog generator" here means any device or set of devices for generating a mist of liquid droplets, dispersed in their own vapor.

The hot water 28, under the effect of the pressure difference between the distributor 3 and the inside of the chamber 1, passes through the fog generator 4 which can be for example a plate metal pierced with a multitude of holes of small diameter, of the order of one hundred micrometers. These holes will advantageously convergent shape. A multitude of hot water jets of small diameter rapidly turning into droplets 23 are then produced by the fog generator 4 in the zone 30 of generating and accelerating fog. The droplets 23 are animated at the output of the mist generator 4 with an upward initial speed 5 inclined at an angle β relative to the vertical A, the module of which is dependent on the pressure in the distributor 3 and the direction determined by the orientation of the fog generator 4.

The term "ascending" must be understood here with reference to the vertical direction A, in the direction going from the lower part 8 to the upper part 9 of the enclosure 1. In other words, an ascending speed comprises at least one vertical component directed towards the high part 9 of the enclosure 1.

Under the effect of the very low pressure (less than the saturation pressure) maintained in the chamber 1, part of the droplets 23 evaporate (flash evaporation transferring the sensible heat of the liquid into latent heat of evaporation) producing a very large volume of steam given the very low density of water vapor at the temperature of hot drops. A mist 6 formed of a mixture of very low pressure steam (for example about 2.4 KPa) and droplets 23 is therefore formed at the output of the mist generator 4, in the zone 30 of generation and acceleration of fog, the mass of vapor representing a few percent of the mass of liquid water in the form of droplets and its volume more than 500 times the volume of the liquid. The droplets 23 and the steam are animated at the generator output 4 of the same initial upward velocity.

The combination of this initial speed and the section available for the steam at the output of the mist generator 4 makes it possible to determine the quantity of vapor that can be produced at the immediate exit of the mist generator 4 in the chamber 1 and therefore the amount of initial energy exchanged during the transformation of the sensible heat of the droplets 23 into latent heat of evaporation.

The upper part 9 of the chamber 1 is kept at a lower temperature (about 13 ° C.) and therefore at a vapor pressure (for example about 1 .2 KPa) lower than the pressure in the lower part 8, the steam leaving the fog generator 4 is thus sucked through the zone 30 for generating and accelerating fog and moves rapidly towards the zone 31 for capturing the chamber 1. The section variation of the chamber 1 in the upper part of the zone 30 for generating and accelerating fog above the fog generator 4 makes it possible to control the expansion of the steam during the upward movement of the vapor, knowing that the droplets under the effect of the decrease in pressure continue to produce steam while cooling, and can guide the flow of droplets in a direction substantially identical to that of the initial speed to reach a speed 5 'at the exit of zone 30.

The steam, under the effect of the friction forces and viscosity, communicates part of its kinetic energy to the droplets 23. Given the very small size of the droplets 23, the friction forces (proportional to the square of the radius of the droplet 23) are much greater than the forces of gravity (proportional to the cube of the radius of the droplet 23). The droplets 23 undergo therefore an acceleration towards the upper part 9 of the enclosure 1. In addition, under the effect of lowering the pressure, the droplets 23 cool down, producing more steam. The expansion of the steam in the fog generation and acceleration zone above the fog generator 4 is controlled by progressively increasing the section of the chamber in the fog generation and acceleration zone 30, above the fog generator 4, to form a divergent, or nozzle.

In this fog generation and acceleration section, a large part of the enthalpy of the steam has been converted into kinetic energy, accelerating the steam and hot water droplets.

This kinetic energy has made it possible both to raise the droplets 23 against gravity in the zone 30 for generating and accelerating fog but also to accelerate them, their speed 5 'at the exit of the part 30 being greater than the speed 5 at the output of the fog generator 4.

The previously described combination of the mist generator 4 followed by an expansion nozzle may also be replaced in another embodiment by a multitude of two-phase nozzles, each having at least one convergent corresponding to a hole of the fog generator 4 of the mode. previous embodiment, a neck and a divergent, contiguous to each other and extended or not a common complementary expansion nozzle when the entire expansion has not been performed in the multitudes of two-phase nozzles.

Thus, in general, the device 1 comprises a generator and fog accelerator assembly, whether it is formed by the mist generator 4 followed by a nozzle or that it is formed of a multitude of two-phase nozzles, followed or no of a common nozzle.

The device, in the embodiment shown, further comprises means for injecting liquid into the capture zone 31. For this purpose, for example, one or more injection nozzles 12 for injecting a sheet 13 of liquid water, continuous and monophasic, under the effect of pressure, are positioned in the chamber 1 above the zone 30 for generating and accelerating fog, in the zone 31 of capture. They are supplied with water under pressure by one or more feed lines 1 1. This water may be cold water from the depths of the ocean, that is, deeper than hot water near the surface, or hot water captured. in the immediate vicinity of the device or a recirculation of a portion of the water collected in an upper collector 16 placed in the upper part 9 of the chamber 1. Figure 6 shows the configuration in which the pressurized water supplying the injection nozzles 12 is cold water 38 from the depths of the ocean by means of a pipe not shown in the figure. This configuration could make it possible to carry out part of the condensation of the vapor thanks to the liquid layer 13 which will be cold, that is to say at a temperature lower than that of the fog in the chamber 1.

The device comprises at least one so-called support surface 14, placed inside the enclosure 1, and extending at least partially in the capture zone 31. The support surface 14 is for example formed on the lateral wall 7 of the enclosure 1. The support surface 14 is inclined at an angle α between 0 and 20 ° relative to the vertical direction A and has a normal whose component parallel to the vertical direction A is directed towards the upper part 9 of the enclosure 1. Thus, the support surface 14 forms a support for any element in contact on the support surface 14 and subjected to its weight. Preferably, the angle of inclination of the support wall 14 is different from 0 °.

The injection nozzles 12 inject cold water along the support surface 14, with an initial upward velocity, that is, directed towards the upper portion 9, substantially parallel to the support surface 14 , so as to form the sheet 13 of liquid water. Thus, the web 13 of liquid water rests on the support surface 14, guided towards the upper part 9 against gravity.

The support surface 14 may be flat or not, knowing that it must allow the sheet 13 of liquid water to remain continuous in its upward flow.

During its flow along the surface 14 of support, the sheet 13 of liquid intercepts the droplets 23 of hot water from the lower part 8 of the chamber 1 where they were accelerated by the steam in the area 30 generation and fog acceleration. These are integrated in the sheet 13 of liquid by communicating a large part of their kinetic energy, causing the sheet 13 of liquid water to the upper part 9. The angle of incidence between the direction of the velocity 5 'of the droplets 23 and the direction of the velocity of the sheet 13 of liquid water, in the capture zone 31, is small, corresponding to the difference between the angles α and β.

The device also comprises means for supplying cold water to ensure the condensation of the vapor formed in the chamber 1.

In the case where the sheet 13 of liquid water is cold water, it contributes in part to the condensation of steam. However, it can only be a small part given the limited heat exchange surfaces. The device therefore comprises means for supplying cold water into the zone 31 for capturing the chamber 1, supplying condensing means.

The condensation means comprise main condensation means, formed by one of the two following means or a combination of both:

A first set of spray nozzles 20 supplied with cold water 38 from the depths of the ocean via a supply device 24, in fluid connection with the cold source, sprays in the chamber 1 a first spray 21 formed of cold water droplets in the area 31 of capture, so that the sheet 13 of liquid water is between the first spray 21 of cold water and the surface 14 of support. In other words, the first spray 21 of cold water is located above the sheet 13 of liquid water and is substantially parallel thereto. Under the effect of their ejection speed, the droplets of the first cold water spray 21 rise in the chamber 1 along the liquid ply 13 towards the upper part 9. By direct contact, they condense the vapor of the fog. They are finally captured by the sheet 13 of liquid under the effect of gravity and / or shocks with the droplets 23 of hot water.

A second set of spray nozzles 18, fed with cold water 38 from the depths of the ocean, via a pipe 25, in fluid connection with the cold source, sprays in the zone 31 of capture of the enclosure 1 a second spray 1 9 formed of droplets of cold water above the stream of droplets 23 of hot water and substantially parallel thereto, so that the stream of droplets 23 of hot water is found between the two sprays 21, 1 9 of cold water. More specifically, the second spray 19 is for example injected into the area 31 for capturing the chamber 1 along a surface of the side wall 7 which is opposite the support surface 14. Under the effect of their ejection speed, the droplets of the second cold water spray 19 rise in the chamber 1 to the upper part 9 in a path substantially parallel to that of the droplets 23 of hot water. By direct contact, they condense the vapor. They are finally captured by the sheet 13 of liquid water.

Advantageously, the lateral wall 7 of the chamber 1, in the capture zone 31, converges towards the upper part 9, so that the section of the chamber 1 decreases towards the upper part 9, the volume of vapor decreasing as and as its condensation.

The device comprises, in the upper part 9 of the enclosure 1, means 26 for evacuating the non-condensed, that is to say the species present in the mist of droplets 23 and water vapor that n have not condensed, thus possibly only residual water vapor that has not condensed.

In order to limit the work to be performed by the means 26 for discharging the non-condensed and the uncondensed vapor portion, the condensation means may comprise auxiliary condensation means 27 installed in the upper part 9 of the enclosure 1 to complete the condensation of steam that would not have been condensed by the main means of vapor condensation. It can be a direct contact exchanger or other and it is for example located in the immediate vicinity of the means 26 for evacuation and is supplied with cold water 38 from the depths.

The means 26 for evacuating the non-condensed at the upper part of the chamber 1 allow the evacuation of the uncondensed gases and the residual water vapor.

The sheet 13 of liquid water is thus charged, as it moves towards the upper part 8 of the enclosure in the capture zone 31, in droplets 23 of hot water from the mist, condensed vapor and cold water droplets of the first spray 21 and the second spray 1 9 of the main condensation means. Thus, in the upper part 9, a liquid water jet 17 is formed consisting of the water coming from the layer 13 of liquid at the outlet of the injection nozzles 12, the water coming from the droplets of water. hot water 23, water from condensed steam and finally cold water sprays 21 and 1 9 from the main condensation means.

Being guided and supported by the support surface 14 during its upward path, the trajectory of the sheet 13 of liquid is imposed and its position in space, in particular its arrival in the upper part 9 of the chamber 1, is thus assured.

As the sheet 13 of liquid flows towards the upper part 9 along the support surface 14, the sheet 13 of liquid gradually loses speed under the effect of gravity. If the web 13 of liquid was not guided by the support surface 14 but free, the horizontal component (quasi-constant given the little friction in the vapor) of its speed would become more and more important compared to its vertical component (decreasing due to gravity). The trajectory of the tablecloth 13 of liquid would become random taking into account the effects variables acting on the sheet 13 of liquid, such as shocks with the droplets 23 of hot water, the movements of the device or the variations of the conditions of the environment in which the device is installed. This is the main problem encountered in the aforementioned devices of the prior art. The support surface 14 makes it possible in particular to avoid these problems by keeping the sheet 13 of liquid in a prescribed trajectory favorable to its capture in the upper part 8 by means 15 of capture.

Shortly before the climax of the trajectory of the liquid ply 13, or more precisely of the liquid water jet 17, the sensing means 15 make it possible to deflect the ply 13 and to discharge it into a collector 16.

The liquid sheet 13 created by the injection nozzles 12 in the lower part of the support surface 14 allows a control of the flow rate and the speed of this sheet 13 of liquid and therefore the kinetic energy that the web 13 will have in part high of the device. It also makes it possible to ensure efficient capture of the droplets 23 of hot water such as cold water droplets of the first spray 21 and / or the second spray 19.

In another embodiment of the present invention, the sheet 13 of liquid flowing on the support surface 14 is not created by injection nozzles 12 but is created by the first droplets 23 of hot water or the droplets of cold water from the first spray 21 striking the support surface 14 to create by successive contributions the web 13 of continuous liquid flowing on the wall 14 of support. In this case, the injection nozzles 12 are not necessary for the device.

The device comprises liquid evacuation means for discharging the liquid water jet 17 which arrives at the upper part of the chamber 1. For this purpose, for example, the collector 16, which may take the form of a rectangular channel, in turn feeds one or more downstream conduits 34, said exhaust pipe 34.

The mechanical energy generated by the device is captured by means of energy recovery. More specifically, the device comprises one or more hydroelectric groups 29a, 29b, 29c each consisting of a hydraulic turbine and a generator.

Three configurations of hydroelectric group are conceivable:

in a first configuration, the hydroelectric group 29a is driven by the flow of liquid 17 flowing out of the manifold 16 into the discharge pipe 34;

in a second configuration, the hydroelectric group 29b is driven by the flow of pressurized water flowing in the supply line 1 1 supplying the injection nozzles 12. As will be seen below, the flow of water 10 supplying the injection nozzles 12 may be cold water from the depths of the ocean, that is to say at a depth greater than that of hot water 28 near the surface, or hot water collected in the immediate vicinity of the device or a recirculation of a portion of the water collected in the upper collector 16; in a third configuration, the hydroelectric group 29c is driven by the hot water flow 28 flowing in the hot water supply pipe 2.

The device can include any of these three configurations, or a combination of two of these configurations, or even the three simultaneous configurations. To facilitate the understanding, the device is shown in Figure 6 as comprising the three group configurations 29a, 29b, 29c hydroelectric.

Any energy uptake decreases the fluid pressure downstream of the hydroelectric group (s) 29a, 29b, 29c. It is, however, necessary for the transformation of the energy generated by the device into mechanical energy and then into electricity.

The first configuration 29a makes it possible in particular to recover energy by reducing the load on the flow of liquid flowing in the evacuation pipe 34 by adapting it very exactly to the necessary value (approximately 1 atmosphere) to its rejection in the ocean 37 outside the chamber 1 where there is a very low pressure. This first configuration also allows, the energy being recovered in the form of an elevation of the altitude of the sheet 13 of liquid, to position the upper part 9 of the device in height, above the level 22 of the ocean ( for example 25m) away from the waves.

"Height" should be understood here as designating the vertical dimension.

The second configuration 29b has the advantage of being able to adjust, by varying the extracted power, the pressure at the level of the injection nozzles 12 and to be able to adapt this pressure to variations in the conditions (hot water temperatures and / or changing cold water, changing demand power, device movements resulting in different geometry, etc.).

The third configuration 29c also makes it possible, by varying the extracted power, to adapt to the conditions, in particular to the temperature of the hot water and to its consequences on the formation of steam and the quantity of energy available.

Figure 6 shows the device in the case where it floats in the ocean 37. The device therefore comprises flotation means, not shown.

This floating configuration of the device has the advantage of avoiding most of the pumping installations in the device, with the possible exception of the means 26 for evacuating the non-condensed gases and the device supplying the final means 27 for condensing.

The pressure differences between the hydrostatic head less the pressure drops in the supply members and the pressure in the chamber 1 can supply the generator 4 fog and the nozzles 12, 20 and 18.

Apart from the very high cost of avoided pumping installations and their complexity, jet or nozzle systems have excellent efficiencies (eg 98%) compared to efficiencies below 90% of pump and motor systems.

In one embodiment, one or more hydroelectric groups 29a, 29b, 29c are reversible ie capable of operating in turbine generator mode and in motor pump mode. In this case, starting the installation and / or its control can be greatly facilitated. Indeed, during the start-up of the installation and during the transitional phases, the sheet 13 of liquid may not have the necessary energy to reach the means 1 5 capture in the upper part 9 1 5, necessary for its evacuation . Additional energy could then be provided by one of the hydroelectric groups 29a, 29b, 29c operating in engine pump mode for the necessary time. We can also mention the possibility of controlling by this means the speed of the tablecloth 13 of liquid, to adjust this speed to allow capture of the droplets 23 of hot water with the least possible energy loss.

FIG. 7 represents a detail of the injection zone in the chamber 1 of the embodiment of FIG. 6 of the liquid layer 13 and the cold water spray 21 by the injection nozzle 12 and the first set of spray nozzles. The pressurized water stream, which is cold depth water 38 according to the first embodiment, feeds the nozzle 12 which generates the web 13 of liquid. Cold water 38 from the depths of the ocean also feeds the first set of spray nozzles 20 through their feed device 24. The feed device 24 may be a pipe or, in the case where the flow of pressurized water supplying the injection nozzles 12 is cold water 38 from the depths, a simple partition wall the first set of spray nozzles being fed directly by the pressurized water stream.

FIG. 8 represents a second embodiment of the chamber 1 of the device, in which the flow of pressurized water supplying the injection nozzle 12 creating the sheet 13 of liquid comes from a recirculation of a part 32 of the flow 17a of liquid flowing in the discharge pipe 34, and from the manifold 16. In this case the flow 17a of liquid flowing in the discharge pipe 34 is divided into a portion 32 becoming the flow pressurized water supplying the injection nozzle 12 and a portion 33 directly discharged into the ocean. This second embodiment makes it possible to use less cold water 38 drawn from the depths of the ocean than in the first embodiment of FIG. 6. This second embodiment makes it possible to obtain a high flow rate for the sheet 13 of liquid and therefore to reduce the necessary height for the same power. The portion 32 of the stream 17a flowing in the discharge pipe 34 is then a mixture of hot and cold water whose temperature depends on their proportion. It will also be necessary to ensure if necessary the condensation of the steam generated by the sheet 13 of liquid. This figure 8 represents the hydroelectric groups 29a, 29c in the first configuration and in the third configuration.

FIG. 9 represents a third embodiment in which the flow of pressurized water supplying the injection nozzle 13 of the liquid ply 13 originates from the immediate proximity of the enclosure 1 and is therefore composed of water hot, that is to say water that has not been pumped from the depths of the ocean, but which remains substantially at a temperature close to or even equal to the temperature of the hot water supplying the generator 4 fog. The flow 17a of liquid flowing into the evacuation pipe 34, draining from the collector 1 6, is firstly turbinated by the hydroelectric group 29a of the first configuration before being discharged into the ocean. This configuration makes it possible to use less cold water 38 in the depths of the ocean than in the first embodiment of FIG. 6. It makes it possible to obtain a high flow rate for the liquid layer 13, the means for supplying the hot water is minimum. However, care must be taken to ensure that the liquid layer 13 cools the generated steam. In Figure 9, there is shown the groups 29a, 29b, 29c hydroelectric in the three configurations.

Figures 1 0 and 1 1 are schematic representations of the complete device according to one embodiment. FIG. 10 represents, in vertical section XX marked in FIG. 11, the complete device in a first embodiment in which it floats on the ocean, oriented in the vertical direction A as before, taking into account the buoyancy criteria . The scales are not preserved so that the figure is more representative.

The device is composed of several enclosures 1 according to one of the embodiments described above.

The speakers 1 are positioned in groups of two symmetrically with respect to a plane 39 perpendicular to the section plane X-X. The enclosures 1 are separated by a central structure 35, the assembly being symmetrical with respect to the plane 39 of symmetry. This symmetry makes it possible to ensure the verticality of the plane 39 in floating configuration.

The central structure may be partially empty or full, the filler to adjust the buoyancy and stability of the device. It can be made of concrete or steel or a combination of both. The filling material may be concrete or any ballast.

Since the device has a symmetrical structure with respect to the plane of symmetry, a certain number of means may be common to several enclosures 1.

For example, FIGS. 10 and 11 show a cold water inlet duct 38, an upper collector 16, a hydroelectric group 29c in the third configuration, an evacuation duct 34 to the ocean, the means 26 for evacuating the non-condensed gases and a pipe 2 'of hot water supply 28 common to several enclosures 1.

FIG. 11 represents the device of FIG. 10 in horizontal section XI-XI marked in FIG.

Twelve speakers 1 constitute the device, symmetrical two by two with respect to the vertical plane 39 of symmetry, each group of two speakers 1 being joined to another group of two speakers 1.

The central structure constitutes the central part of the device.

Each enclosure 1 shows at the level of the X-X cutting plane in Figure 1 0 the support surface 14 on which flows the web 13 of liquid, surmounted by the first spray 21 of cold water. In the embodiment shown, the support surfaces 14 are planes. Flat support surfaces 14 make it possible to ensure a stable flow to the sheet 13 of liquid, avoiding the need to concentrate this web 13 of liquid in the width direction, the width remaining constant. This gives a more efficient device.

The droplets 23 of hot water in the fog in the chamber 1, in their race towards the upper part 9, occupy the top of the first spray 21, themselves surmounted by the second spray 19 of cold water 1 9. Of course the other embodiments described above could be adapted.

The outer surface 36 of the wall 7 of the chamber 1 subjected to hydrostatic external pressure has been shown in Figure 1 1 in the form of a vault to ensure good resistance. These arches rest on walls 40 which allow both to transfer efforts to the central structure 35 but also to separate the successive speakers 1. Thus, a floating device having good buoyancy, stability and safety characteristics is obtained. The dimensions could be for a total power of 100MW electric of 200m of length for a total width of 60m and a height of 80m of which 25m above the surface of the ocean.

Each enclosure 1 can be used separately or in groups of two which allows both to modulate the power provided by the entire device but also to stop the speakers 1 for maintenance or repair while the others are in operation.

FIG. 12 represents a second embodiment of the device according to the present invention in which the enclosure 1 has a circular symmetry of revolution about a vertical axis 41.

The support surface 14 is conical, of the same vertical axis 41 and whose normal is directed upwards, that is to say towards the upper part 9 as described above. This arrangement makes it possible to maintain the support on the support surface 14 of the sheet 13 of liquid. This sheet 13 of liquid is concentrated during its rise to the upper part 9.

The first spray 21 of cold water and the sheet 13 of liquid each form conical surfaces of vertical axis 41, surrounded by the flow of hot droplets 23 also forming a cone around the vertical axis 41, themselves surrounded by the spray 19 also conical shape of vertical axis 41.

This embodiment could have an advantage over the embodiment shown in Figure 1 1 for lower power plant (few MW).

Figure 13 shows an enclosure 1 containing two support surfaces 14. It may be noted that the number of support surfaces 14 may be greater than two in the same enclosure 1.

This configuration makes it possible to reduce the necessary height of the enclosure 1 above the part 30 of generation and fog acceleration.

Indeed, this height is conditioned by the horizontal dimension in the section plane of the chamber 1 (that is to say perpendicular to the direction of extensions of the chamber 1) and the angle between the trajectory of the hot drops 23 and the wall 14, this angle corresponding to the difference between the angles a and β. For reasons of efficiency of the energy transfer, this angle must be as low as possible, which increases very substantially the height of the device. A configuration with several support surfaces 14 makes it possible to reduce this necessary height.

In the configuration shown in FIG. 13, each of the support surfaces 14 has its collector 16 in the upper part 8 as well as its steam condensation means fed with cold water 38 from the depths.

Since the device is essentially composed of concrete, the cost of producing electricity could be particularly competitive in an oceanic environment of islands with high energy costs and energy independence, which is not guaranteed. is a non-CO2 emitting renewable energy in unlimited quantities and 24-hour operation.

In the example presented, the hot fluid is liquid water and the cold fluid is also liquid water. It may however be provided otherwise. In particular, the hot fluid may be a two-phase mixture, for example in the case where the hot source is a geothermal source with a presence of steam or any other gas in the hot fluid. It is also possible to provide the possibility of dissolved elements in the hot fluid (as is the case in seawater with its dissolved salts).

Claims

claims

A device for converting thermal energy contained in a first hot fluid of a hot source and a second cold fluid of a cold source into mechanical energy, the temperature of the hot fluid being greater than the temperature of the cold fluid, the device comprising at least:

An enclosure (1) delimited by a lateral wall (7) resistant to external pressure, the enclosure (1) being maintained at an internal pressure lower than the external pressure, the enclosure (1) comprising, in one direction ( A) vertical from the bottom upwards, a lower part (8), a zone (30) for generating and accelerating fog, a zone (31) for capturing, extending above the zone (30), fog generation and acceleration, and an upper portion (9);

• means (2) for supplying the hot fluid into the lower portion (8) of the enclosure (1);

A generator and fog accelerator assembly in the zone (30) for generating and accelerating fog, making it possible to generate, from the hot fluid, a mist formed of droplets (23) of hot liquid dispersed in the vapor formed by their own partial evaporation and accelerate by expansion this two-phase fluid at an upward speed, that is to say comprising at least one component in the direction (A) vertical directed towards the upper portion (9) of the enclosure (1) ;

Condensation means in the capture zone (31) for condensing the vapor produced, by cooling with the cold fluid;

Means (24, 25) for supplying the cold fluid to the collection zone (31) supplying the condensation means (1 8, 20);

Means (1 6) for collecting liquid (1 7) in the upper part (9) of the chamber (1);

• means (34) for evacuation in the upper portion (9) of the chamber (1) allowing the evacuation of all or part of the fluids (1 7) out of the enclosure (1);

Energy recovery means (29a, 29b, 29c) for generating mechanical energy by liquid turbines;

characterized in that it comprises at least:

a so-called support surface (14) extending at least partially in the capture zone (31), the support surface (14) being inclined at an angle (a) between 0 and 20 ° with respect to the direction (A) vertical and having a normal whose component parallel to the vertical direction (A) is directed towards the upper portion (9) of the enclosure (1), the droplets (23) of hot liquid accelerated out of the zone (30) for generating and accelerating the fog of the enclosure (1) integrating into it comm uniquant all or part of their kinetic energy in a sheet (13) of liquid formed by at least the coalescence of the droplets ( 23) of hot liquid on the support surface (14), the web (13) of liquid flowing on the support surface (14) with an upward velocity to the liquid collection means (1 6) (1). 7). Device according to claim 1, further comprising means (26) for evacuating the non-condensed in the upper part (9) of the enclosure (1) allowing the evacuation of the non-condensable gases and the fraction of vapor which would not have been condensed between the lower portion (8) and the upper portion (9) of the enclosure (1).

Device according to Claim 1 or Claim 2, characterized in that the device comprises means (12) for injecting fluid onto the support surface (14).

Device according to Claim 3, characterized in that the fluid injection means (12) for forming the liquid ply (13) comprise at least one liquid injection nozzle (12) positioned in the chamber (1) for forming the web (13) of liquid flowing on the support surface (14) with an upward initial velocity (5).

Device according to claim 3 or claim 4, characterized in that the means (12) of injection to form the sheet (13) of liquid are adapted to be connected to a source of cold fluid outside the device.

Device according to any one of claims 3 to 5, characterized in that the means (12) of injection to form the sheet (13) of liquid are adapted to be connected to a source of hot fluid outside the device.

Device according to any one of claims 3 to 6, characterized in that the injection means (12) for forming the sheet (13) of liquid are connected to the upper portion (9) of the enclosure (1), so that they are fed by the recirculation of at least a portion of the liquid (17) means (16) of collection.

Device according to any one of the preceding claims, characterized in that the means (18, 20) of condensation comprise at least one nozzle (20) of spray for projecting into the chamber (1) a spray (21) of liquid cold animated with an ascending speed, substantially parallel to the wall (14), so that the sheet (13) of liquid is between the first (21) cold liquid spray and the surface (14) of support.

Device according to any one of the preceding claims, characterized in that the means (18, 20) of condensation comprise at least one nozzle (1 8) of spray for projecting a spray (19) of cold liquid animated with an ascending speed and substantially parallel to the droplet flow (23) along a surface opposite to the support surface (14) in the enclosure (1).

10. Device according to any one of the preceding claims characterized in that it comprises means for controlling and controlling the energy recovery means taking into account the conditions prevailing in the enclosure (1). 1 1. Device according to any one of the preceding claims, characterized in that the energy recovery means (29a, 29b, 29c) comprise at least one reversible turbine which can be used as a pump.

12. Device according to any one of the preceding claims characterized in that the means (29a, 29b, 29c) of energy recovery are associated with the means (1 1) for supplying the liquid to the injection means (12). the liquid web (13) and / or the means (2) for supplying the hot fluid and / or the means (16, 34) for discharging the liquid.

13. Device according to any one of the preceding claims characterized in that it comprises means for flotation in water.

14. Installation for converting mechanical energy of thermal energy comprising a hot source and a cold source, the installation further comprising a device according to any one of the preceding claims and wherein the hot source is water to the surface of a body of water, the means (2) for supplying the hot liquid being in fluid connection with the hot source, and the cold source is water at depth of the same body of water, the means (24, 25) for supplying the cold liquid being in fluid connection with the cold source. 15. Installation according to claim 14, wherein the body of water is an ocean (37).