WO2014111577A2

WO2014111577A2 - Facility and method for producing mechanical or electrical energy from a fluid at a temperature higher than ambient temperature

Info

Publication number: WO2014111577A2
Application number: PCT/EP2014/051040
Authority: WO
Inventors: Chuen-yu John CHAN; Marc Raynal; Siyang Ray HU
Original assignee: Chan Chuen-Yu John; Marc Raynal
Priority date: 2013-01-18
Filing date: 2014-01-20
Publication date: 2014-07-24
Also published as: FR3001254B1; FR3001254A1; WO2014111577A3

Abstract

A facility for producing mechanical or electrical energy from a fluid (9) at a temperature higher than ambient temperature, comprising the following in succession: - at least one air/fluid heat exchanger (17) for receiving at least a portion of the fluid and transferring heat from the received fluid to the air entering the heat exchanger, so as to obtain heated air and cooled fluid (13), - at least one turbine (21) for expanding the heated air and obtaining mechanical or electrical energy, - at least one first intermediate conduit for conveying the heated air from the heat exchanger to the turbine, and - a chimney (5) for receiving the expanded air and releasing it into the atmosphere. The facility comprises at least one substantially converging inlet conduit (15) for taking in outside air (27) and delivering at least a fraction of the incoming air to the heat exchanger, and a second intermediate conduit (23) for conveying the expanded air from the turbine to the chimney. Corresponding method.

Description

Installation and method for producing mechanical or electrical energy from a fluid at a temperature above room temperature.

Technical area.

The present invention relates to an installation for producing mechanical or electrical energy from a fluid at a temperature greater than ambient temperature, of the type comprising successively:

at least one air-fluid heat exchanger for receiving at least a portion of the fluid and transferring heat from the received fluid to air entering the heat exchanger, thereby obtaining heated air and cooled fluid, the heat exchanger defining a longitudinal direction of circulation of the air in the heat exchanger,

at least one turbine for relaxing the heated air and obtaining expanded air and mechanical or electrical energy,

at least one first intermediate duct for conveying the heated air from the heat exchanger to the turbine, and

- a chimney, preferably divergent, to receive the relaxed air and put it in the atmosphere.

The invention also relates to a corresponding method for producing mechanical or electrical energy, and to a power plant comprising the aforementioned installation.

The invention applies in particular to the conversion into electricity of heat lost by a power plant, for example a solar plant, thermal or nuclear.

State of the art

The heat is generally lost as residual water at a temperature above room temperature, but low, typically between 45 ° and 100 ° C. The heat of the residual water is most often discharged into the environment, for example in a river or in the sea by heat exchange. In the case of nuclear power plants, the cooling of the residual water takes place in one or more cooling towers. The heat thus lost by a plant typically represents 50 to 65% of the heat produced by the plant and limits its thermal efficiency. In some favorable cases, some of the heat dissipated is used in direct heating, in cogeneration, but it is not transformed into mechanical or electrical energy. Most often, the cooling of the residual water remains an operation that consumes energy.

In countries where natural water is scarce, typically in South Africa, it is known to use air cooling systems generally in the form of roof-shaped condensers, cooled by fans placed underneath,

To produce electricity, a chimney was built in 1983 in Manzanarès, Spain, then dismantled in 1988. Its operation consisted in heating the air in transit under a transparent greenhouse of 122 m radius, occupying a floor area of 46 760 m ² , using the heat of the sun, and channeling hot air to a 200 m high chimney in the center of the greenhouse. The movement of the air was obtained because the density of the hot air is lower than that of the cold air, the heated air naturally heading towards the chimney and operating during its passage a turbine located in the fireplace. The maximum air velocity observed in this device was 12 m / s in the neck of the chimney. The chimney of Manzanarès produced a maximum electric power of 50 kW.

Patent FR-B-2 903 740 belonging to the present applicant describes a divergent, telescopic, self-sustaining carbon fiber chimney producing electricity by displacing air into the chimney due to (i) a difference in pressure between the ground and the altitude, (ii) the cooling of the air in the chimney having the effect of increasing its speed by conservation of the energy.

However, neither in Manzanarès nor in the aforementioned document it is envisaged to recover the heat present in the residual water of a thermal power plant.

The document DE-A-198 21 659 also describes a greenhouse of 4 km x 4 km on the ground heating air. The air is heated at night by coils in which water flows from a neighboring solar power station. The air is evacuated by a chimney 1000 m high. Calculations show that, in such an installation, the air circulates at low speed, less than 10 m / s in the greenhouse and between 10 and 20 m / s in the chimney, the thermal power dissipated from the remaining solar power station. low, despite a very large footprint of the greenhouse and a high chimney height.

Brief description of the invention.

An object of the invention is therefore to propose an installation making it possible to value the heat present in a fluid, for example a residual water coming from a Power generation plant, to produce mechanical or electrical energy, and with a moderate footprint and height.

For this purpose, the subject of the invention is an installation for producing mechanical or electrical energy from a fluid at a temperature above room temperature of the type described above, the installation comprising at least one duct of substantially convergent inlet for withdrawing outside air and delivering to the heat exchanger at least a fraction of the incoming air, and a second intermediate duct for conveying the expanded air from the turbine to the chimney.

According to particular embodiments, the installation comprises one or more of the following characteristics, taken in isolation or in any technically possible combination:

the first intermediate duct is substantially convergent and is adapted to accelerate the air conveyed to the turbine at a speed at the outlet of the first intermediate duct of between 150 m / s and 250 m / s, preferably equal to approximately 210 m / s;

- The intake duct is adapted to accelerate the air at a speed at the outlet of the intake duct between 50 m / s and 100 m / s, preferably equal to about 64 m / s;

the inlet duct defines at the entrance a surface for the passage of outside air and at the outlet a surface for passage of air towards the heat exchanger, the ratio obtained by dividing the area of the passage surface into entering through the area of the exit passage area being between 2 and 3, preferably between 2.3 and 2.7;

the intake duct comprises: a lateral envelope comprising a substantially plane upper wall and a lower wall parallel to one another, and two lateral walls each extending between the upper wall and the lower wall, and a plurality of flow guides; distributed transversely between the two side walls and defining for the outside air a plurality of substantially convergent passages, each of the flux guides and each of the two side walls having a downstream portion oriented substantially in the longitudinal direction;

each of the flux guides, and preferably also each of the side walls, has a substantially parabolic profile;

the heat exchanger comprises pipes substantially parallel to the longitudinal direction in order to circulate the fluid in a heat exchange zone of the heat exchanger;

the heat exchanger comprises an inlet of air situated longitudinally on the inlet duct side, an air outlet situated longitudinally on the side opposite to the air inlet, each of the ducts being fluidly connected to another of the ducts; pipes for forming a plurality of "U" pipes, each "U" pipe having an inlet for accepting a fraction of the fluid and an outlet for discharging a fraction of the cooled fluid, all the "U" pipes being oriented so as to that the inlets and outlets of the "U" pipes point longitudinally towards one of the air inlet and the air outlet of the heat exchanger, preferably towards the air intake of the heat exchanger;

- The pipes are arranged at the nodes of a rectangular mesh network, the heat exchanger comprising metal spacers connecting the pipes to each other along the sides of the mesh of the network, each of the spacers having two longitudinal edges fixed on the pipes. spacers and pipes defining longitudinal airflow corridors in the heat exchanger;

the heat exchanger comprises a fluid distribution assembly and a cooled fluid collection assembly, the distribution assembly including at least one inlet manifold and distribution pipes connected at regular intervals to the inlet manifold. a flow direction of the fluid in the inlet manifold, the manifold assembly having at least one outlet manifold and manifold pipes connected at regular intervals to the outlet manifold in a flow direction of the cooled fluid in the outlet manifold the inlet manifold having a fluid passage cross-section tapering to an end of the inlet manifold in the fluid flow direction, the passage section having an area increasing in proportion to the distance between the flow section and the passage and the end of the inlet manifold, the outlet manifold having a passage section increasing in the flow direction of the cooled fluid in the outlet manifold from an end of the outlet manifold, the outlet manifold passage section having an area increasing in proportion to the distance between the outlet manifold passage section and the end of the output manifold;

- The heat exchanger has metal fins fixed to the pipes, the fins extending longitudinally and projecting radially from the pipes.

the outer shells of one or more of the following elements can be dismantled to allow maintenance: the air intake duct, the air-fluid heat exchanger, the first intermediate duct, the turbine, the second duct; intermediate and the chimney.

The invention also relates to a method for producing mechanical or electrical energy from a fluid at a temperature above room temperature, the method comprising at least the following steps: heat transfer in at least one air-fluid heat exchanger of at least a portion of the fluid to air entering the heat exchanger to obtain heated air and cooled fluid, the heat exchanger heat defining a longitudinal direction of air circulation in the heat exchanger,

- routing by a first intermediate duct of the heated air of the heat exchanger to at least one turbine,

- relaxing the heated air in the turbine to obtain relaxed air and mechanical or electrical energy, and

- venting of the air relaxed by a chimney, preferably divergent,

characterized in that it further comprises the following steps:

- intake of outside air by at least one substantially convergent inlet duct and delivery of the air taken from the heat exchanger, the air delivered by the intake duct providing at least a fraction of the incoming air , and

- routing by a second intermediate duct air expanded from the turbine to a chimney.

According to particular embodiments, the method implements an installation as described above, including in the particular embodiments of the installation described above.

Finally, the invention relates to a power generation plant producing a fluid at a temperature above ambient temperature, for example a solar, thermal or nuclear power plant, the power plant:

comprising an installation as described above, the installation producing mechanical or electrical energy from the fluid produced by the power plant, or

implementing a method as described above, the process producing mechanical or electrical energy from the fluid produced by the power plant.

Description of the Figures

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

- Figure 1 is a top view of an installation according to the invention comprising six energy production lines similar to each other; Figure 2 is a side view of one of the power generation lines of the installation shown in Figure 1;

Figure 3 is a top view of the power generation line shown in Figure 2;

Figure 4 is a side view of the power generation line shown in Figures 2 and 3, without part of the chimney;

Figure 5 is a top view of the air intake duct and an upstream portion of the heat exchanger of the power generation line shown in Figures 2 to 4;

- Figure 6 is a sectional view along a vertical longitudinal plane of a portion of the heat exchanger of the production line shown in Figures 2 to 4;

Figure 7 is a sectional view along a transverse plane of a portion of the heat exchanger of the production line shown in Figures 2 to 4; and

- Figure 8 is a top view of the fluid collector of the heat exchanger of the production line shown in Figures 2 to 4.

Detailed description of the invention.

Referring to Figure 1, there is described a plant 1 for generating electricity. The installation 1 comprises six production lines 3A to 3F and a common stack 5 to the six production lines 3A to 3F. According to variants not shown, the installation 1 comprises a number of production lines of any kind, ranging for example from one to twelve.

The installation 1 comprises ducts 7 supplying each of the production lines 3A to 3F with a fluid 9 coming from a thermal power station (not represented), and ducts 1 1 discharging from each of the production lines 3A to 3F a cooled fluid. 13.

The fluid 9 is for example distilled water. The fluid 9 comes for example from a condenser (not shown) of the thermal power plant. The fluid 9 is at a temperature of between 45 ° C and 100 ° C, for example at about 54 ° C.

The cooled fluid 13 is at a temperature between δ'Ό and 45 ^q C, for example about 33 ° C.

The production lines 3A to 3F are advantageously similar. They are arranged radially from the stack 5. The production lines 3A to 3F are angularly distributed regularly around the stack 5. In the example shown, two successive production lines form an angle of 60 °. Since the production lines 3A to 3F are similar, only the production line 3A will be described below, with reference to FIGS. 2 to 4.

The production line 3A successively comprises an air intake duct 15 in the installation 1, a heat exchanger 17 defining a longitudinal direction L of air circulation, a first intermediate air duct 19, a turbine 21 air expansion, and a second intermediate air duct 23 opening into the chimney 5. The production line 3A further comprises an electricity generator 25 mechanically connected to the turbine 21.

A transverse direction T substantially perpendicular to the longitudinal direction L and substantially horizontal is also defined.

The duct 15 for admission of air is at the periphery of the installation 1 (Figure 1).

As can be seen in FIG. 5, the air intake duct 15 draws outside air 27 and delivers air 29 entering the heat exchanger 17. The duct 15 comprises an external envelope 31 delimiting as input a passage surface 33 of the outside air 27 and at the outlet of a passage surface 35 of the air 29 entering the heat exchanger 17.

By "passage surface" or "passage section" of a flow means a surface which is in each of its points substantially perpendicular to the flow lines. The "speed" of the air is understood for example as the average speed of the air on a surface of passage of the air.

The terms "upstream" and "downstream" refer to the direction of the air flow in the installation 1 and not with respect to the circulation of the fluid 9.

The duct 15 is substantially convergent, that is to say that the successive air passage surfaces have substantially decreasing areas in the direction of air flow. The duct 15 is advantageously aerodynamically profiled to reduce the pressure losses in the air flowing in the duct 15.

The duct 15 is able to accelerate the air leaving the duct 15 at a speed of between 50 m / s and 100 m / s.

The passage surface 33 is located on the periphery side of the installation 1. The passage surface 33 has a convexity turned towards the outside of the duct 15.

The passage surface 35 is substantially flat and perpendicular to the longitudinal direction L.

The ratio of the area of the inlet passage surface 33 to the area of the outlet passage area is between 2 and 3. Advantageously, it is between 2.3 and 2.7 and is for example 2.5. The outer wall 31 of the duct 15 comprises an upper wall 37 (FIG. 4), a lower wall 39 and two lateral walls 41, 43 (FIG. 5) connecting the upper wall 37 to the lower wall 39. The duct 15 further comprises flow guides 45A to 45D to reduce the pressure losses of the air in the duct 15 and downstream of the duct 15.

The upper wall 37 and the lower wall 39 are substantially horizontal and flat.

The side walls 41, 43 are vertical. The side walls 41, 43 are for example high about 2.5 m and extend longitudinally about 5 to 6 m for example. They are also curved, with a convexity turned towards the inside of the duct 15. The lateral walls 41, 43 each comprise a downstream portion 45, 47 oriented substantially longitudinally. In other words, each of the downstream portions 47, 49 is tangent to a vertical plane parallel to the longitudinal direction L.

The flow guides 45A to 45D extend from the passage surface 33 of the outside air 27 to the passage surface 35 of the air 29 entering the heat exchanger 17. The flow guides 45A to 45D are vertical and arranged transversely fanwise between the side walls 41, 43, preferably regularly. The flux guides 45A to 45D advantageously have dimensions similar to those of the side walls 41, 43.

The flow guides 45A to 45D define with the outer wall 31 of the duct 15 substantially convergent air passages 51A to 51E. The flux guides 45A to 45D further comprise a downstream portion 53A to 53D oriented substantially longitudinally. In other words, each of the downstream portions 53A to 53D is substantially tangent to a vertical plane parallel to the longitudinal direction L.

The heat exchanger 17 comprises an outer casing 55 defining an air circulation duct substantially in the longitudinal direction L. The heat exchanger 17 further comprises an air inlet 57 connecting the heat exchanger 17 to the duct 15, and an air outlet 59 connecting the heat exchanger 17 to the first intermediate duct 19.

The heat exchanger 17 comprises a heat exchange assembly 61 between the air and the fluid 9, a fluid distribution assembly 9 in the exchange assembly 61, and a collector assembly 64 for collecting the cooled fluid. 13 from the exchange unit 61.

The outer shell 55 has a constant cross section. The outer shell 55 is fiberglass. According to variants, the outer casing 55 is made of any other airtight material, insulating, and adapted to withstand a vacuum inside the heat exchanger 17, for example of the order of 4 to 5 kPa. The inlet 57 and the outlet 59 have for example a square section.

The exchange unit 61 extends in the longitudinal direction L in a heat exchange zone 62, for example a length L1 of about 10 m.

In FIG. 6, the exchange unit 61 comprises a plurality of "U" exchange pipes 65.

Each exchange pipe 65 (FIGS. 6 and 7) extends in a substantially vertical plane. The base of the "U" is oriented towards the air outlet 59 of the heat exchanger 17. The branches of the "U" are oriented towards the air inlet 57 of the heat exchanger 17.

Each exchange pipe 65 comprises a fluid circulation hose 9 co-current with the air, a pipe 69 for circulating the fluid 9 against the current of air, and a connecting pipe 71 connecting the pipe 67 to the pipe 69 and forming the base of the "U".

The connection pipes 71 are for example in a semicircle.

The co-current pipes 67 are for example organized according to thirty-eight superimposed horizontal planes P1 having seventy-six pipes 67 extending longitudinally. The pipes 67 are connected on the upstream side of the heat exchanger 17 to the fluid distribution assembly 9.

Each countercurrent pipe 69 is for example located above the co-current pipe 67 belonging to the same "U" exchange pipe 65.

The countercurrent pipes 69 are for example organized according to thirty-eight superimposed horizontal planes P2 having seventy-six pipes 69 extending longitudinally. The pipes 69 are connected on the upstream side of the heat exchanger 17 to the collector assembly 64.

Plans P1 and P2 alternate vertically.

The pipes 67, 69, 71 have for example an outside diameter of about 19 mm and a thickness of 1 mm. They are for example aluminum or copper. The pipes 67, 69 extend substantially in the longitudinal direction L along the length L1.

As seen in Figure 7, the pipes 67, 69 are arranged at the nodes of a mesh network 73 rectangular, for example square.

The pipes 71 are advantageously aerodynamically profiled in the longitudinal direction L to reduce the pressure losses of the air in the heat exchanger 17.

The pipes 67, 69 having metal fins 72 fixed to the pipes 67, 69. The fins 72 extend longitudinally and project radially from the pipes 67, 69.

The fins 72 are for example twenty in each pipe 67, 69, and divided into four groups of five fins 72 per mesh 73 of the network. The fins 72 have by example a section perpendicular to the longitudinal direction L of triangular shape. For example, the triangular section of the fins 72 has a thick base of about 1 mm and a radial extension of about 4 mm.

Spacers 75 connect the pipes 67, 69 along the sides of the meshs 73 of the network. Each spacer 75 has two longitudinal edges 77 fixed on two of the pipes 67, 69.

The spacers 75 have for example the length L1 in the longitudinal direction L, a width of 28 mm between two pipes 67, 69, and a thickness of 3 mm. The spacers 75 are made of aluminum or copper.

The horizontal struts 75 are formed of two half-struts 75A and 75B fixed one in the extension of the other during assembly of the heat exchanger 17 through a 75C system of male-female moldings.

The pipes 67, 69 located in the vicinity of the outer casing 55 are connected to the outer casing 55 by spacers 79 along the sides of the meshes 73 of the network.

The struts 75, 79 advantageously comprise a profiled edge 80 situated on the upstream side of the heat exchanger 17, in order to reduce the pressure losses in the air at the point where the air splits on the struts 75, 79 .

The pipes 67, 69 and the fins 75, 79 define longitudinal circulation corridors 81 for the air. The circulation corridors 81 are, in the example shown, 77 x 77. The circulation corridors 81 have a width L2 in the transverse direction T of about 44 mm and have a height H of about 44 mm. Advantageously, the circulation corridors 81 have a lateral envelope in all points substantially parallel to the longitudinal direction L.

As can be seen in FIGS. 5 and 8, the fluid distribution assembly 9 is situated longitudinally upstream of the exchange assembly 61. The fluid distribution assembly 9 comprises inlet manifolds 83 connected to the pipe 7 supplying the production line 3A with fluid 9, and distribution pipes 85 connecting the inlet manifolds 83 to each pipe to be connected. current 67 of the exchange unit 61.

The inlet manifolds 83 are, in the example shown, the number of thirty-eight. The inlet manifolds 83 extend substantially in horizontal planes P1. The inlet manifolds 83 are oriented substantially horizontally in a direction D1 forming an angle of approximately 45 ° with the longitudinal direction L. Each inlet manifold 83 has an inlet 86 of fluid 9, and an end 87 opposite to the entry 86 according to direction D1.

The end 87 is closer to the exchange pipes 65 than the inlet 86 and located longitudinally further downstream than the inlet 85. In addition, each inlet manifold 83 defines, from the inlet 86 to the end 87, passage sections perpendicular to the direction D1 having a proportionally reduced area as a function of the distance in the direction D1. In other words, the area of a passage section 89 located at a distance d from the end 87 has an area substantially proportional to the distance d.

The distribution pipes 85 extend in the thirty-eight planes P1 and are thirty-eight in each plane P1. Each distribution pipe 85 has a first transverse portion 91, and a second longitudinal portion 93 separated from the first portion 91 by a bend at about 90 °.

The first portions 91 of all the distribution pipes 85 of one of the planes P1 are connected at regular intervals along the longitudinal direction L to the inlet manifold 83 extending in the plane P1 in question. The first portions 91 are advantageously aerodynamically profiled in the longitudinal direction L to reduce the pressure losses of the air in the heat exchanger 17.

The second portions 93 are connected to co-current pipes 67 of the plane P1 in question.

The collector assembly 64 of the cooled fluid 13 has a structure similar to that of the fluid distribution assembly 63. The collector assembly 64 will not be described in detail. The collector assembly 64 (FIG. 5) comprises outlet collectors 95 extending substantially in horizontal planes P2 and oriented in a direction D2, of which there are thirty-eight, and collector pipes 97 for collecting the cooled fluid 13 from countercurrent pipes 69.

The outlet manifolds 95 include an outlet 99 for the cooled fluid 13 and an end 101. Each outlet manifold 95 defines, from the end 101 to the outlet 99, passage sections of the cooled fluid 13 perpendicular to the direction D2 having an area increasing proportionally with the distance in the direction D2.

According to an alternative embodiment, the inlet manifolds 83 and the outlet manifolds 95 are replaced by a single inlet manifold and a single outlet manifold (not shown), both advantageously in the form of dihedron.

The first intermediate duct 19 comprises a casing 103 located in the extension of the casing 55 of the heat exchanger 17.

The envelope 103 defines an inlet 105 of the first intermediate duct 19 corresponding to the outlet 59 of square section of the heat exchanger 17, and an outlet 107 located at the inlet of the turbine 21 and of substantially circular section. The casing 103 advantageously has an aerodynamic shape making it possible to pass from the square shape of the inlet 105 to the substantially circular shape of the outlet 107.

The envelope 103 is of substantially convergent shape. Envelope 103 is capable of increasing the velocity of air between inlet 105 and outlet 107 by a factor of about three, for example from about 64 m / s to about 210 m / s.

The turbine 21 is located at a neck of the production line 3A, that is to say at the location having the smallest air passage section.

The turbine 21 may comprise one or more stages, comprising for example a stator 109, a rotor 1 1 1, and a shaft 1 13 mechanically connecting the rotor 1 1 1 to the electricity generator 25.

The second intermediate duct 23 comprises an outer casing 1 15, an inner casing 1 17 in the form of a drop, and an outlet section 1 19 through which the second intermediate duct opens into the chimney 5.

The inner envelope 1 17 surrounds the electricity generator 25 and divides the flow of air leaving the turbine 21 around the electricity generator 25.

The outlet section 1 19 is substantially horizontal.

The outer casing 1 15 and the inner casing 1 17 define a passage 121 substantially divergent for air. The outer casing 1 15 and the inner casing 1 17 have a general shape advantageously aerodynamic to reduce the pressure losses in the air. The general shape of the outer shell 1 is curved upwardly on the side of the outlet section 1 19 to move the air from a horizontal circulation to a substantially vertical circulation.

The passage 121 is able to reduce the speed of the air between the outlet of the turbine 21 and the outlet section 1 19 of the second intermediate duct 23 by a factor of about 2.

The chimney 5 comprises a base 123 fixed in the ground and a frustoconical portion 125 fixed on the base 123.

The chimney 5 has a height of between 10 m and 200 m.

The base 123 comprises six sectors 127A to 127F (Figure 3) arranged angularly about a vertical axis V, and a bulb 129 located between the six sectors 127A to 127F.

Each sector 127A to 127F receives the second intermediate conduit 23 of the corresponding production line 3A to 3F.

The frustoconical portion 125 is divergent upwards. For example, its lower diameter is about 7 m and its greater diameter is about 21 m. The part frustoconical 125 is advantageously substantially adiabatic. For example, the frustoconical portion 125 is carbon fiber.

The operation of the installation 1 will now be described. The operation of the production lines 3A to 3F being similar, only the operation of the production line 3A will be described.

The fluid 9, in the example of water, arrives at the production line 3A through the pipe 7 (Figures 1, 3 and 5) from the thermal power station (not shown). The fluid 9 comes for example from one or more condensers (not shown) and has a temperature of 54 ° C.

The fluid 9 enters the distribution system 63 of the heat exchanger 17 (Figure 5). The fluid 9 arrives firstly in the thirty-eight inlet manifolds 83, in which it flows from the inlet 86 to the end 87 in the direction D1. The fluid 9 is then distributed in the first portions 91 (FIG. 8) of the distribution pipes 85. Due to the fact that the passage section 89 of the inlet manifolds 83 is substantially proportional to the distance d, the fluid 9 circulates substantially at the same speed in all the first portions 91 of the distribution pipes 85.

The fluid 9 flows through the second portions 93 of the distribution pipes 85 and enters the co-current pipes 67 of the exchange pipes 65 (FIGS. 6 and 8). The fluid 9 then circulates longitudinally along the planes P1 and co-flows with the air circulating in the heat exchanger 17. Arrived at the air outlet 59 of the heat exchanger 17, the fluid 9 takes the connecting pipes 71 and enters the countercurrent pipes 69. The fluid 9 then circulates longitudinally along the P2 planes against the current with the air circulating in the heat exchanger 17.

The fluid 9 gives heat to the air circulating in the heat exchanger 17 and becomes the cooled fluid 13.

The struts 75, 79 and the fins 72 provide good thermal contact between the fluid 9 and the air flowing in the heat exchanger 17. Each pipe 67, 69 can transfer about 5 kW of thermal power. The pipes 67, 69 being 76 x 76, or 5776, the total thermal power transferred to the air by the production line 3A is about 29 MW. For the installation 1, comprising the six production lines 3A to 3F, the thermal power transferred to the air by the heat exchangers 17 is approximately 174 MW.

At the outlet of the countercurrent pipes 69, the cooled fluid 13 is approximately 33 'Ό. The cooled fluid 13 then enters the manifold assembly 64 (Figure 5). The cooled fluid 13 passes through the collecting pipes 97 and arrives in the outlet manifolds 95. The cooled fluid 13 flows in the outlet manifolds 95 from the end 101 to the outlet 99 in the direction D2.

Due to the fact that the outlet manifolds 95 have a passage section whose area increases proportionally with the distance, the cooled fluid 13 circulates substantially at the same speed in the header pipes 97.

The distribution pipes 85 and the collecting pipes 97 pass through the envelope 55 of the heat exchanger 17. The air and water tightness constraint of the heat exchanger 17 is simpler to satisfy. that the distribution assembly 63 and the collector assembly 64 are located upstream of the exchange unit 61. The depression inside the exchanger 17 is the weakest upstream of the exchange unit 61.

The cooled fluid 13 leaving the outlet manifolds 95 is finally returned to the thermal power plant by the pipe 1 1 (Figures 1, 3 and 5).

The outside air 27 enters the intake duct 15 (FIGS. 2 to 5) through the passage surface 33. At the passage surface 33, the air has a velocity of approximately 25 m / s. The air entering the intake duct 15 takes the convergent passages 51 A to 51 E and leaves the passage surface 35.

The passage surface 35 is also the air inlet 57 in the heat exchanger 17. At the passage surface 35, the air 29 entering the heat exchanger 17 has a speed of about 64.degree. m / s. The velocity of the air is multiplied by about 2.5 between the passage surface 33 and the passage surface 35 of the intake duct 15.

The air temperature drops about Ι Ο 'Ό between the passage surface 33 and the passage surface 35, which improves the thermal efficiency of the heat exchanger 17.

In addition, due to the longitudinal orientation of the downstream portions 45, 47, and 53A to 53D of the intake duct 15, the air enters the heat exchanger 17 at the passage surface 35 substantially parallel to the longitudinal direction L.

The air entering the heat exchanger 17 passes between the pipes 85, 97 of the distribution assembly 63 and the collector assembly 64. The air then enters the longitudinal circulation corridors 81 (FIGS. 6 and 7). ) where it exchanges heat with the fluid 9. the air temperature increases from about 34 ^<Ό during this exchange. The enthalpy of the air, between the inlet 57 and the outlet 59 of the heat exchanger 17, increases by about 34 kJ / kg.

With the conformation of the heat exchanger 17, the air passes through the heat exchanger 17 with a reduced pressure drop, preferably less than about 1 1 kPa. The velocity of the air in the heat exchanger 17 greatly increases the heat exchange between the fluid 9 and the air. Indeed, the heat exchange is normally lower between a liquid such as water and a gas such as air. Due to the speed of the air in the heat exchanger 17, the heat exchange is comparable to that existing between two liquids.

The heated air leaving the heat exchanger 17 enters the first intermediate duct 19 (FIGS. 3 and 4). Between the inlet 105 and the outlet 107 of the first intermediate duct 19, the speed of the air is multiplied by about three. In the example shown, it goes from about 64 m / s to about 210 m / s.

The air therefore enters the turbine 21 at about 210 m / s and transfers part of its energy to the turbine 21. The energy transferred is recovered as mechanical energy on the shaft 1 13 and converted into electrical energy by the electricity generator 25. The electricity production of the facility 1 is about 16 MW.

Since the thermal power station produces about 174 MW of electricity, the 16 MW electrical output produced by the installation 1 represents a production gain of about 9%. Depending on the operating conditions, the gain in electricity production is up to 25%.

In addition, there is no additional C02 emission related to this production gain. In addition, the installation 1 allows the thermal power plant to dispense with the water of a river as a cold source. The outside air 27 plays indeed the role of cold source.

The air, after passing through the turbine 21, takes the second intermediate duct 23. By passing on the inner casing 17, the air recovers the heat produced by the electricity generator 25.

Thanks to the second intermediate duct 23, the air passes from a substantially longitudinal circulation to a vertical circulation between the outlet of the turbine 21 and the outlet section 1 19 of the second intermediate duct 23. The passage 121 of the second intermediate duct 23 being diverging, the speed of the air is reduced between the outlet of the turbine 21 and the outlet section 1 19. The air speed is for example 96 m / s at the entrance to the chimney 5.

At the outlet of the frustoconical portion 125 of the chimney 5, the air has a reduced speed with respect to the speed at the inlet of the frustoconical portion. The output speed of the frustoconical portion 125 is for example about 1 1 m / s. The air pressure at the outlet of the frustoconical portion 125 is substantially equal to the atmospheric pressure at 200 m altitude. The operation explained above corresponds to a steady state of the installation 1, when the air reached the high speeds mentioned above. In order to start the production lines 3A to 3F, the turbines 21 are started by supplying electrical energy to the generators 25 which then function as driving motors of the turbines 21.

Then, the fluid 9 from the thermal power plant is circulated in the heat exchangers 17. The kinetic energy of the air passing through each turbine 21 increases gradually. The generators 25 then stop driving the turbines 21 which are driven by the air flow.

We will now describe an advantageous method for constructing the installation 1, more specifically the heat exchanger 17.

To manufacture the heat exchanger 17, rigid vertical panels 127 are firstly made by welding (FIG. 8) comprising the "U" exchange pipes 65 and the vertical spacers 75, 79 which are intended to be located substantially. in the same vertical longitudinal plane of the heat exchanger 17.

Then, for each panel 127, the half-entraines 75A, 75B horizontal intended to be located on either side of one of the panels 127 transversely are welded to the panels 127 to obtain complete panels 129.

Then, the complete panels 129, seventy-six in the example shown, are welded to one another along the grooves 75C half-spacers 75A, 75B. The assembly of the complete panels 129 is for example reinforced by aluminum strapping (not shown) extending in transverse planes, distributed along the length of the heat exchanger 17.

With the characteristics described above, the installation 1 uses the heat present in the fluid 9 to produce about 16 MW of electricity. Calculations show that, for a comparable footprint, the energy supplied by the installation 1 is approximately 4120 times greater than that of the Manzanarès chimney. The height of the chimney 5 is furthermore not greater than that of the chimney of Manzanares.

Thanks to the characteristics described above, the installation 1 is therefore much more efficient than the aforementioned prior art installations.

Alternatively (not shown), the installation 1 is devoid of electricity generator. The mechanical energy recovered on the shafts 1 13 is then used directly, for example by means of a hydraulic circuit for any use. Industrial applications.

The present invention makes it possible to increase the electricity production of any thermal power plant from the heat released into the environment, without any additional fuel, by producing no industrial waste or any additional greenhouse effect, and by not drawing on the fresh water of rivers, which is the traditional cold source of thermal power stations.

On the ecological level, the invention makes it possible on the one hand to preserve the natural fresh water by preventing it from being evaporated in an industrial process, and on the other hand to avoid rejecting hot effluents in the rivers causing disturbances in the natural environment. The invention also makes it possible to increase the guaranteed electricity production without any C02 emission.

On the industrial level, the invention makes it possible to increase the net electricity production of any thermal power station from 10% to 25%, without using additional fuel, for an investment cost per kW equivalent to that of a power plant. gas.

Further information.

The coolant 9, for example water, circulates advantageously in a closed circuit. The ambient air acts as a cold source for the thermal power plant to which the installation 1 is connected. This makes it possible to advantageously construct the installation 1 in a location that is substantially devoid of water resources.

Installation 1 makes it possible to recover the heat generated by a thermal power station. The recovery is carried out by means of a heat-transfer liquid, typically water, thanks to a high-speed passage of air in the heat exchanger 17. The temperature of the air is thus reduced by the increase of the air velocity (conservation of energy), thus allowing a better heat transfer between the coolant and the air in transit in the heat exchanger.

As can be seen in FIG. 5, each of the flux guides 45A to 45D substantially has a parabolic shape profile. Advantageously, it is the same for the side walls 41, 43.

The flux guides 45A, 45B and the wall 41 have shapes that are transversely opposite to the flux guides 45C, 45D and to the wall 43. For example, the flux guides 45A, 45B and the wall 41 are substantially symmetrical with the flow guides. 45C, 45D and the wall 43 with respect to a plane P parallel to the longitudinal direction L. The plane P is for example a median plane of the heat exchanger 17, preferably substantially vertical.

The substantially parabolic and convergent fan shape of the intake duct 15 makes it possible to very substantially reduce the pressure losses in the air.

The intake duct 15 is provided with flux guides in the form of a parabola beam. This allows a reduction of the passage section of the incoming air a very small distance compared to a circular intake duct around the chimney 5 such as a greenhouse arranged circularly around the chimney.

The laboratory experiments conducted by the inventors, as well as calculations, have shown that the intake duct 15 in the form of a parabola beam further reduces the pressure drops. Indeed, the fluid at the exit of the beam, over the entire width of the intake duct, moves substantially parallel to the longitudinal direction L. This eliminates or greatly reduces the formation of vortices generating loss of pressure.

The intake duct 15 according to the invention implements a reduced floor area compared to the case of a radial air inlet. In the example, the reduction is about 38%.

Thus, the installation 1 has a lower footprint than would be necessary for a circular greenhouse shaped intake duct.

In addition, installation 1 occupies a surface area of 3643 m ² (diameter 68 m) to generate 16 MW, a production ratio of 4.39 kW / m ² . For comparison, the solar tower (in English Solar tower) Manzanares occupied a floor area of 46,760 m ² (diameter 244 m) to produce 50 kW, a ratio of 0.00107 kW / m ² . The installation 1 according to the invention is therefore about 4,000 times more effective than the Solartower Manzanares and other similar devices in terms of footprint required.

On the other hand, the intake duct 15 makes it possible to accelerate the air up to a high speed at the inlet of the heat exchanger 17. The circular greenhouse is an example of a linearly convergent heat exchange duct. not very effective compared to the present invention.

Claims

1. - Installation (1) for producing mechanical or electrical energy from a fluid (9) at a temperature above room temperature, the installation (1) comprising successively:

at least one air-fluid heat exchanger (17) for receiving at least a portion of the fluid (9) and transferring heat from the fluid (9) received to air (29) entering the heat exchanger (17), to obtain heated air and cooled fluid (13), the heat exchanger (17) defining a longitudinal direction (L) of air circulation in the heat exchanger (17). )

at least one turbine (21) for expanding the heated air and obtaining expanded air and mechanical or electrical energy,

at least a first intermediate duct (19) for conveying the heated air from the heat exchanger (17) to the turbine (21), and

- a chimney (5), preferably divergent, to receive the air relaxed and put it in the atmosphere,

characterized in that the plant (1) comprises at least one substantially convergent inlet duct (15) for withdrawing outside air (27) and delivering at least a fraction of the heat exchanger (17) to the heat exchanger (17). an incoming air (29), and a second intermediate duct (23) for conveying the expanded air from the turbine (21) to the chimney (5).

2. - Installation (1) according to claim 1, characterized in that the inlet duct (15) defines at the entrance a surface (33) for the passage of outside air (27) and at the outlet a surface (35) passing air to the heat exchanger (17), the ratio obtained by dividing the area of the inlet passage surface (33) by the area of the exit passage surface (35) being included between 2 and 3, preferably between 2.3 and 2.7.

3. - Installation (1) according to claim 1 or 2, characterized in that the intake duct (15) comprises:

a lateral envelope (31) comprising an upper wall (37) and a lower wall (39) substantially plane and parallel to each other, and two lateral walls (41, 43) each extending between the upper wall (37) and the lower wall (39), and

a plurality of flux guides (45A, 45B, 45C, 45D) distributed transversely between the two lateral walls (41, 43) and defining for the outside air (27) a plurality of passages (51A, 53B, 530, 53D, 53E) substantially convergent, each of the flux guides (45A, 45B, 450, 45D) and each of the two side walls (41, 43) comprising a downstream portion (47A, 47B, 47C, 47D, 47, 49) oriented substantially in the longitudinal direction (L).

4. - Installation (1) according to claim 3, characterized in that each of the flow guides (45A, 45B, 45C, 45D), and preferably also each of the side walls (41, 43), has a substantially parabolic profile .

5. - Installation (1) according to any one of claims 1 to 4, characterized in that the heat exchanger (17) comprises pipes (67, 69) substantially parallel to the longitudinal direction (L) to circulate the fluid (9) in a heat exchange zone (62) of the heat exchanger (17).

6. - Installation (1) according to claim 5, characterized in that the heat exchanger (17) comprises an air inlet (57) located longitudinally on the side of the intake duct (15), an outlet of air (59) located longitudinally on the opposite side to the air inlet (57), each of the pipes (67, 69) being fluidly connected to another of the pipes (67, 69) to form a plurality of U-shaped pipes "(65), each" U "pipe (65) having an inlet for admitting a fraction of the fluid (9) and an outlet for discharging a fraction of the cooled fluid (13), all" U "pipes ( 65) being oriented so that the inlets and outlets of the "U" pipes point longitudinally towards one of the air intake (57) and the air outlet (59) of the exchanger heat (17), preferably to the air inlet (57) of the heat exchanger (17).

7. - Installation (1) according to claim 5 or 6, characterized in that the pipes (67, 69) are arranged at the nodes of a mesh network (73) rectangular, the heat exchanger (17) having metal spacers (75) connecting the pipes (67, 69) to each other along the sides of the mesh (73) of the network, each of the spacers (75) having two longitudinal edges (77) fixed to the pipes (67, 69) , the spacers (75) and the pipes (67, 69) defining longitudinal heat passages (81) in the heat exchanger (17).

8. - Installation (1) according to any one of claims 5 to 7, characterized in that the heat exchanger (17) comprises a set (63) of fluid distribution (9) and a collector assembly (64) cooled fluid (13), the dispensing assembly (63) having at least one inlet manifold (83) and distribution pipes (85) connected at regular intervals to the inlet manifold (83) in one direction (D1) fluid flow (9) in the inlet manifold (83), the manifold assembly (64) having at least one outlet manifold (95) and manifold pipes (97) connected at regular intervals on the outlet manifold (95) in a cooled fluid flow direction (D2) (13) in the outlet manifold (95), the inlet manifold (83) having a fluid passage cross-section (89) (9) ) narrowing up to one end (87) of the inlet manifold (83) in the fluid flow direction, the passage section (89) having an area increasing in proportion to the distance (d) between the passage section (89) and the end (87) of the inlet manifold (83), the outlet manifold (95) having a passage section increasing in the direction (D2) of circulation of the cooled fluid (13) in the outlet manifold (95). ) from an end (101) of the outlet manifold (95), the outlet manifold passage section (95) having an area increasing in proportion to the distance between the outlet manifold passage section (95) and the end (101) of the outlet manifold (95).

9. - A method for producing mechanical or electrical energy from a fluid (9) at a temperature above room temperature, the method comprising at least the following steps:

- heat transfer in at least one air-fluid heat exchanger (17) of at least a portion of the fluid (9) to air (29) entering the heat exchanger (17) to obtain heat heated air and cooled fluid (13), the heat exchanger (17) defining a longitudinal direction (L) of air circulation in the heat exchanger (17),

- routing by a first intermediate duct (19) of the heated air of the heat exchanger (17) to at least one turbine (21),

- relaxing the heated air in the turbine (21) to obtain expanded air and mechanical or electrical energy, and

- venting of the air expanded by a chimney (5), preferably divergent,

characterized in that it further comprises the following steps:

- intake of external air (27) by at least one intake duct (15) substantially convergent and delivery of the air taken from the heat exchanger (17), the air delivered through the intake duct ( 15) providing at least a fraction of the incoming air (29), and

- Routing by a second intermediate conduit (23) of the expanded air of the turbine (21) to a chimney (5).

10. The method of claim 9, wherein the first intermediate duct (19) is substantially convergent and adapted to accelerate the air conveyed to the turbine (21) at an output speed (107) of the first intermediate duct (19) included between 150 m / s and 250 m / s, preferably equal to about 210 m / s.

1 1. A method according to claim 9 or 10, wherein the intake duct (15) is adapted to accelerate the air at a speed at the outlet of the intake duct (15) between 50 m / s and 100 m / s, preferably equal to about 64 m / s.