FR2997177B1 - MEANS FOR EXCHANGING THERMAL LIQUID / GAS, IN PARTICULAR WATER / AIR, AND SYSTEM FOR PRODUCING WATER FROM HUMIDITY OF THE AIR COMPRISING SUCH MEANS - Google Patents

Abstract

The means (4) for heat exchange water / air are adapted to receive a stream of cold water flowing inside walls of said means whose outer faces are in contact with said air flow. They comprise at least one module (21, 22, 23, 24, 25) consisting of two metal plates (26, 27) held at a small distance from one another and connected to each other in a sealed manner , the cold water circulating inside each module between the two plates (26, 27), and the air flowing outside the plates (26, 27).

Description

Means for liquid / gas heat exchange, in particular water / air, and system for producing water from the humidity of the air, comprising such means

The present invention relates to liquid / gas heat exchange means, especially water / air, adapted to equip such a liquid water production system from the humidity of the air by condensation of a portion of the steam of water contained in a flow of air passing along cooled walls.

The present invention furthermore relates to a system for producing liquid water from the humidity of the air by condensing a portion of the water vapor contained in an air flow passing along cooled walls, this system comprising such water / air heat exchange means.

Numerous liquid / gas heat exchange means, in particular water / air, and many liquid water production systems of the above types are known. The cooled walls of such a system must obviously be maintained at a temperature less than or equal to that of the dew point corresponding to the pressure and the temperature of the air around the system.

It is known from WO96 / 03347, a system of the above type comprising a cold water production device and means for circulating said cold water inside water / air heat exchange means having walls whose outer faces are in contact with a flow of air. The heat exchange means water / air are constituted by a coil inside which circulates the cold water and around which circulates the flow of air.

The cold water production device described in this document comprises a known conventional refrigerant group using a refrigerant fluid and comprising a compressor, a condenser, an expansion valve, and an evaporator immersed in a cold water tank. This cold water is pumped and circulates through the coil. The condensed water returns to the cold water tank.

The object of the present invention is to overcome the drawbacks of the aforementioned means and system, and to propose liquid / gas heat exchange means, in particular water / air, and a system of the aforementioned types having improved characteristics in terms of heat exchange, having a liquid / gas exchange surface, in particular water / air, raised in a limited volume, and, in the case of a water production system, improved capacity in terms of quality of the obtained water, and energy consumption.

The liquid / gas heat exchange means, in particular water / air, targeted by the invention are adapted to receive a stream of liquid, especially cold water, circulating inside walls of said heat exchange means whose outer faces are in contact with said flow of gas, in particular air.

According to a first aspect of the present invention, the liquid / gas heat exchange means, in particular water / air, of the aforementioned type are characterized in that they comprise at least one plate module, each module consisting of two metal plates. held at a small distance from one another and sealed to each other, the liquid, especially cold water, flowing inside each module between the two plates, and the gas, in particular the air circulating outside the two plates of each module.

This structure makes it possible to obtain for each module a ratio, higher than for the liquid / gas heat exchange means, in particular water / air, known, between the total liquid / gas heat exchange surface, in particular water / air, the two plates of each module and the volume occupied by the latter whose thickness may be small compared to the two main dimensions of each plate.

This characteristic gives the liquid / gas heat exchange means, in particular water / air, according to the present invention a high heat exchange efficiency. In the case of heat exchange water / air, one obtains a high efficiency of condensation of the humidity of the air, which results in a low energy consumption per unit volume of condensed water, and therefore a low cost of this water.

The temperature of the cold water, also called chilled water, must be lower than that of the dew point, and may be very close to 0 ° C so as to obtain the greatest possible difference between the temperature of the cooled surfaces and that of the air flow, and therefore an increased efficiency of the condensation of the water vapor contained in the moist air passing through the water / air heat exchange means.

According to one embodiment of the invention, the liquid / gas heat exchange means, in particular water / air, comprise a predetermined number of plate modules arranged substantially parallel to each other at a short distance from one another , the number of modules being, in the case of heat exchange water / air, chosen according to the production of water provided under predetermined reference conditions of pressure, temperature, humidity, flow, flow of air passing through the heat exchange means water / air.

In this way, it is easy in the latter case, to provide each user with water / air heat exchange means according to the present invention having the number of modules best suited to his needs and the climatic conditions prevailing in his environment.

In addition, it is very easy in the latter case to design a cold water production device perfectly adapted to the conditions of use provided for such water / air heat exchange means. In this case, the modular design of the water / air heat exchange means according to the present invention thus makes it possible to optimally adapt them to the local climatic conditions, temperature, pressure, and humidity of the air, provided for their use. .

According to another embodiment of the invention, the modules are contained within an enclosure of which at least some partitions are metallic and are in thermal contact with the plates of the modules, the flow of gas, in particular air , also circulating between each of said metal partitions and the adjacent metal plate of the nearest module, these metal partitions being advantageously externally coated with a thermally insulating coating.

Thus, in the case of heat exchange water / air, the walls of the chamber also constitute cooled walls participating in the condensation of moisture contained in the air flow through the heat exchange means water / air .

The thermal insulating coating makes it possible to better insulate the inside of the enclosure thermally, and to reduce the heat losses and therefore the energy consumption, particularly in the case of water / air per unit volume of the water obtained.

According to an advantageous embodiment of the invention, the two metal plates of the same module are held at a small distance from each other by their respective edges, at least some of a plate being bent in relief towards the other. other plate, for example shaped so as to form a tube with the corresponding complementary shaped edge of the other plate, the two plates being connected to each other sealingly along said edges.

This feature allows easy assembly of two plates of the same module, and modules between them.

According to another embodiment of the invention, in the space separating two contiguous modules is disposed at least one metal sheet substantially parallel to the plates of said modules and in thermal contact with said plates, for example along opposite edges of said plates, and in that at least one metal sheet is advantageously disposed between each end module and the adjacent partition of the enclosure.

Each metal sheet in thermal contact with the plates of the modules is thus maintained at a temperature close to that of said plates. In the case of heat exchange water / air, it therefore participates in the condensation function of the moisture of the air flow passing through the water / air heat exchange means.

Each metal sheet thus makes it possible to substantially add a surface of contact and liquid / gas heat exchange, in particular water / air, equal to the surface of the plates facing the two adjacent modules without modifying the total volume of the assembly.

Thus, for example, a first metal sheet having the same area of contact with the gas, in particular moist air, that the plates of a module doubles the liquid / gas contact surface, in particular water / air, in space separating two contiguous modules.

According to another aspect of the invention, the system for producing liquid water from the humidity of the air of the aforementioned type comprising a device for producing cold water and means for circulating said cold water to the water. interior of water / air heat exchange means whose outer faces are in contact with said air flow, is characterized in that it comprises water / air heat exchange means according to the first aspect of the invention .

According to one embodiment of the invention, the device for producing cold water is a closed circuit device advantageously comprising control means arranged to maintain the temperature of the cold water upstream of the modules below. a predetermined set value.

This avoids any risk of mixing the cold water flowing inside the device with the condensed water produced by the system. It also avoids, if necessary, any risk of pollution of water condensed by cold water flowing in closed circuit, or vice versa.

According to an advantageous version of the invention, the system comprises a single fan, or group of fans, and advantageously comprises airflow guiding means arranged in such a way that the flow of air which has circulated along the plates condensation modules is then used to evacuate the heat generated by the operation of the cold water production device, the fan, or group of fans, being placed advantageously at the outlet of the air flow and sucking the moist air to through the system.

According to one embodiment of the invention, the system comprises, if necessary, means for treating the condensed water produced to render, if necessary, the quality of this water complies with the requirements of the regulations applicable to drinking water.

According to another embodiment of the invention, the cold water production device comprises a refrigerating unit operating by compression and expansion of a refrigerant fluid, the evaporator of said refrigeration unit being immersed in a cold water tank of device. Other features and advantages of the present invention will become apparent from the following description.

In the accompanying drawings, provided solely by way of nonlimiting examples: FIG. 1 represents a schematic diagram in front view, with cutouts, of an embodiment of a water production system according to the present invention; invention; FIG. 2 is a top view, broken away, of a group of five condensation modules according to the embodiment of the present invention shown diagrammatically in FIG. 1. FIG. 3 is a schematic perspective view of one of the Figure 4 is a horizontal sectional view of a detail of the group of condensing modules shown in Figure 2, according to a variant of the invention.

Figure 1 schematically shows a system 1 for producing liquid water from the moisture of the air by condensation of a portion of the water vapor contained in a flow of air passing along cooled walls.

In known manner, the system 1 comprises a device 2 for producing cold water (also called iced water), and pumping means, generally a known pump 3, for circulating said cold water inside means 4 water / air heat exchange having cooled walls whose outer faces are in contact with said air flow.

In the example shown diagrammatically in FIG. 1, the cold water production device 2 comprises a refrigeration unit of any known type, using any known refrigerant fluid, comprising a compressor 5, a pressure reducer 6, an evaporator 7, and a condenser 8, shown schematically in FIG.

In known manner, the evaporator 7 is immersed in a reservoir 9 of cold water of the device 2.

In known manner, the compressor 5 compresses the refrigerant fluid, which raises the temperature of said fluid which then passes into the condenser 8, schematized by an air-cooled coil, wherein said coolant condenses at least partially, with decrease its sensible heat and evacuation of the corresponding latent heat of condensation. The cooled condensed coolant then passes into the expander 6 and then into the evaporator 7, where it is vaporized with cold production. The water contained in the cold water tank 9 is thus cooled, the amount of heat lost by this water substantially corresponding to the latent heat of vaporization of the refrigerant absorbed by said fluid.

The temperature of the cold water inside the tank 9 can thus be maintained at a predetermined temperature which can be close to 0 ° C. The cold water contained in the reservoir 9 is sent by the pump 3 into a pipe 12 which supplies the water / air heat exchange means 4 of the system 1.

In the present invention, the cold water having passed through the heat exchange means 4 returns to the tank 9 via a return pipe 13. The cold water circuit is therefore a closed circuit.

In the example shown schematically in FIG. 1 and shown in detail in FIGS. 2 to 4, the water / air heat exchange means 4 comprise at least one condensation module, in this example five modules 21, 22, 23, 24, 25 to plates. Each condensation module 21, 22, 23, 24, 25 consists of two metal plates 26, 27 held at a small distance from each other and connected to each other, in any known manner, such that waterproof.

In the example of FIGS. 2, 3, 4, the two plates 26, 27 of each module are held at a small distance from one another and connected to each other by their respective edges, the vertical edges 34,35, and the horizontal edges 40, 41.

Some edges of at least one plate 26,27, the vertical edges 34,35 to the figures, are curved in relief towards the other plate 27,26. In this example, they are shaped so as to form respectively a tube 36, 37, with the correspondingly complementary edges 35, 34 of the other plate 27, 26. The two plates are sealingly connected to each other along said edges 34, 35, in any appropriate manner.

In the example shown, the vertical edges 34, 35, of each plate 26 are folded a first time, towards the outside of the module, at 28, then folded twice in the other direction, at 29, 30, then a last time in the first direction, along an edge 31, to form a vertical tongue 32 which is assembled in any known manner, for example by welding, brazing, gluing, etc., to the tongue 32 of the plate associated 27 symmetrically shaped.

In this embodiment, the vertical edges 34 and 35 are thus shaped so as to each form a respective tube 36, 37. In this example, the tube 36 receives at its base a pipe 38 for the arrival of cold water, the other tube 37 having at its upper part a tube 39 for output and return of water to the reservoir 9 through the pipe 13. The tubes 36, 37 may have a section of any shape, substantially square to the figures, and of any suitable size.

The upper 40 and lower 41 horizontal edges are assembled to each other in any way. The cold water arriving through the tubing 38 is thus distributed by the tube 36 over the entire height of the corresponding module 21, 22, 23, 24, 25, and circulates inside said module between the two respective plates 26, 27 of which the respective outer faces 42, 43 are in contact with the moist air flow which passes through the system 1 and which circulates outside the two plates 26, 27 of each module 21, 22, 23, 24, 25.

In the example of FIG. 2, the system 1 comprises a predetermined number, equal to 5 in this figure, of modules 21, 22, 23, 24, 25 with plates 26, 27 arranged substantially parallel to one another at a short distance. one of the other.

The number of condensation modules is chosen according to the water production provided for the system 1 under predetermined reference conditions of pressure, temperature, humidity, flow, air flow passing through the system 1.

In the embodiment of FIG. 2, the modules 21, 22, 23, 24, 25 of the system 1 are contained inside a metal enclosure 44, at least some of which are metal partitions 45, 46, vertical to FIGS. and 4, are in thermal contact respectively with the corresponding adjacent plates 26, 27 of the end modules 21, 25, in this example along the tubes 36, 37.

The air flow thus flows between each of said metal partitions 45, 46 and the corresponding adjacent metal plate 26, 27, of the module 21, 25, the closest.

The other metal partitions 47, 48, shown in Figures 2 and 4, perpendicular to the partitions 45, 46 and in thermal contact with the latter, are also at a low temperature close to the temperature of the cold water circulating in the modules.

The metal partitions 45, 46, 47, 48 of the enclosure 44 are advantageously externally coated with a thermally insulating coating, schematized at 49, of any known insulating material.

In the embodiment shown in FIGS. 2 and 4, in the space 51 separating two contiguous modules, the modules 21 and 22 in the figure, is disposed at least one metal sheet 52 substantially parallel to the respective adjacent walls 26, 27, of said modules 21, 22, and in thermal contact with these walls 26, 27, for example along the tubes 36, 37, opposite edges 34, 35 of these walls, 26, 27.

In the example shown, two metal sheets 52, 53 are inserted between the vertical tubes 36, 37, modules 21, 22 and are clamped between these vertical tubes. The metal sheets 52, 53 are also shaped so as to provide between them and between them and the adjacent plates 26, 27, air passage spaces of substantially equivalent widths.

In the same way, a metal sheet 54 is inserted and clamped between the vertical tubes 36 and 37 of the condensation module 21 and the adjacent partition 45 of the metal enclosure 44, so as to be in thermal contact with the latter. The plate 54 is shaped so as to extend substantially equidistantly between the partition 45 of the enclosure 44 and the plate 26 of the module 21 in the corresponding space 55.

It thus appears that the auxiliary metal plates 52, 53, 54 are also maintained at a low temperature very close to the temperature of the cold water circulating inside the modules 21 to 25, and also function as cold walls, which substantially increases the total area of the cooled exterior surfaces in contact with the humid air circulating inside the system. It is obviously possible to insert plates such as 52 and 53 in all the spaces 51 between adjacent modules, and a sheet 54 between the other end module 25 and the adjacent partition 46.

In the example shown, the system 1 comprises a single fan, or group of fans, 61, placed here at the outlet of the air flow.

The fan, or group of fans, 61 is, in this example, arranged in such a way that the moist air flow sucked by said fan 61 penetrates inside the system 1 (arrows 62), passes through a filter 63, d any known type, then passes into the spaces 51 between adjacent modules, and 55 between the end modules 21, 25, and the adjacent walls 45, 46 of the metal enclosure, from top to bottom in the diagram of the FIG. 1, (arrows 64), passes through the condenser 8 (arrow 65) to cool the refrigerant flowing through this condenser 8, passes through the fan, or group of fans, 61, (arrow 66), and leaves towards the outside (arrow 67). The moist air thus sucked through the system 1 passes along the cooled walls formed by the plates 26, 27 of the modules 21 to 25, the partitions 45, 46, 47, 48 of the metal enclosure 44, and the metal sheets 52, 53, 54 inserted either between two adjacent modules, or between an end module 21, 25, and the adjacent partition, 45, 46 of the enclosure 44.

In contact with these plates, partitions and cold sheets, the moisture of the air condenses and forms drops of water which are collected at the bottom of the system 1, under the enclosure 44, in a tank 71. The water , schematized at 72, collected in the tray 71 is then directed outwardly in any manner, for example by a pump, shown schematically at 73, to be conveyed, as shown schematically by the arrow 74, to the places of use of this water.

In some cases, and if the need arises, at least part of this water can be directed to conventional means of potabilization, known in themselves and shown schematically in 75, to treat the water produced and make the quality of this water complies with the requirements of the regulations in force regarding drinking water. These means may comprise, for example filtration, chlorination, irradiation, mineralization means, etc. known in themselves.

The plates 26, 27, modules, the partitions 45 to 18 of the enclosure 44, the metal sheets 52, 53, 54, are made of a metal known as a good thermal conductor and adapted for contact with food, for example aluminum, and / or copper and / or stainless steel.

A liquid water production system of modular design has thus been described, the number of condensation modules being chosen so as to obtain a predetermined water production under predetermined conditions of pressure, temperature, relative humidity and humidity. flow, the flow of moist air through the system.

It has also been described a water / air heat exchanger which can be used alone, by itself, independently of the cold water production system described above, and more generally as a high performance liquid / gas heat exchanger with a large surface area. heat exchange per unit volume, which can also receive a hot gas and a cold liquid.

It is understood that the cold water production device may alternatively be an adsorption device using the adsorption and desorption capacity of adsorbents, known in themselves, such as silica gel, zeolite, or other, such a device advantageously using hot water from a source of hot water located near the system. The electrical energy required for the operation of the liquid water production system according to the present invention can obviously be provided by a conventional electrical power distribution network. This electrical energy can also be provided by wind turbines, and / or solar panels.

Claims (10)

1. Means (4) of liquid / gas heat exchange, in particular water / air, adapted to equip in particular a system (1) for producing liquid water from the humidity of the air by condensation of a part water vapor contained in a flow of air passing along cooled walls, these means being adapted to receive a stream of liquid, in particular cold water, flowing inside the walls of said heat exchange means whose outer faces are in contact with said flow of gas, in particular air, characterized in that said liquid / gas heat exchange means (4), in particular water / air, comprise at least one module (21, 22, 23, 24, 25), each module (21, 22, 23, 24, 25) consisting of two metal plates (26, 27) held at a small distance from each other and connected to each other. the other in a sealed manner by their respective edges (34, 35, 40, 41), the liquid, especially cold water, flowing inside each module (21, 22, 23, 24, 25) between the two plates (26, 27), and the gas, in particular the air, flowing outside the two plates (26, 27) of each module (21, 22, 23, 24, 25), said liquid / gas heat exchange means, in particular water / air, advantageously comprising a predetermined number of plate modules (21, 2.2, 23, 24, 25) (26, 27). ) arranged substantially parallel to each other at a short distance from each other. 2. Means for liquid / gas heat exchange, in particular water / air, according to claim 1, characterized in that the modules (21, 22, 23, 24, 25) of the system (1) * are contained in the interior of an enclosure (44) at least some of whose walls (45, 46, 47) are metallic, in thermal contact with the modules (21, 22, 23, 24, 25), the flow of gas, in particular air also circulating between each of said metal partitions (45, 46, 47) and the adjacent metal plate (26, 27) of the nearest module (21, 25), said metal partitions being advantageously externally coated with a thermal insulating coating ( 49). 3. Means for liquid / gas heat exchange, in particular water / air, according to any one of the preceding claims, characterized in that some edges (34,35) of at least one plate (26,27) are bent in relief to the other plate (27, 26) of the same module, and are for example shaped so as to form a tube (36, 37) with the corresponding edge (35, 34), shaped in a complementary manner, the other plate (27,26), the two plates (26,27) being sealingly connected to one another along said edges. 4. Means for liquid / gas heat exchange, especially water / air according to any one of the preceding claims, characterized in that in the space (51) separating two contiguous modules is arranged at least one metal sheet (52,53 ) substantially parallel to the plates (26, 27) of said modules and in thermal contact with said plates (26, 27), for example along opposite edges (34, 35) of said plates (26, 27), and that less a metal sheet (54) is advantageously disposed between each> end module (21,25) and the adjacent partition (45,46) of the enclosure (44). 5. System (1) for producing liquid water from the humidity of the air by condensing a part of the water vapor contained in a flow of air passing along cooled walls, this system (1) comprising a device (2) for producing cold water and means (3) for circulating said cold water inside water / air heat exchange means whose outer faces are in contact with said flow characterized in that it comprises means (4) for heat exchange water / air according to any one of the preceding claims. 6. System according to claim 5 itself dependent on claims 3 and 4, characterized in that the tubes (36, 37) of each module (21, 22, 23, 24, 25) are arranged vertically, in that a first tube (36) receives at its base a cold water inlet pipe (38) which is thus distributed over the entire height of the module, the other tube (37) having at its upper part a pipe (38) water outlet, and in that the at least one (the) metal sheet (s) (52, 53) is (are) advantageously clamped (s) between the tubes (36, 37) which. advantageously have a substantially square section. 7. System according to claim 5 or 6, characterized in that the device (2) for producing cold water is a closed circuit device advantageously comprising control means arranged to maintain the temperature of the cold water. upstream of the modules below a predetermined setpoint. 8. System according to one of claims 5 to 7, characterized in that the system (1) comprises a single fan, or group of fans, (61) and advantageously comprises airflow guide means arranged in a manner such that the flow of air which has circulated along the cold plates (26, 27) of the condensing modules (21, 22, 23, 24, 25) is then used to evacuate the heat generated by the device (2) cold water production, the fan, or group of fans, (61) being advantageously placed at the outlet of the air flow and drawing the moist air through the system (1). 9. System according to any one of claims 5 to 8, characterized in that the system (1) comprises means (75) for treating the produced water to render, if necessary, the quality of this water complies with the requirements of applicable regulations. 10. System according to any one of claims 5 to 9, characterized in that the device (2) for producing cold water comprises a refrigerating unit (5, 6, 7, 8) operating by compression and expansion of a refrigerant, the evaporator (7) of said refrigerating unit being immersed in a reservoir (9) of cold water of the device (2). "