FR2982936A1 - Cooling device i.e. dry cooler for use in air conditioning system of e.g. building, has parallelepiped panel configured to be moved in translation and/or rotation to vary section of application surface applying gas flow on panel - Google Patents

Abstract

The device has a cooling unit placed in a gas flow (10) i.e. air flow, including a material to be humidified. The cooling unit includes a parallelepiped panel (2) comprising the material to be humidified. The panel is configured to be moved in translation and rotation so as to vary a section of an application surface (20) applying the gas flow on the panel. The panel occupies an extreme open position in which the section of the surface is minimal. The panel is directed, so that a plane containing the surface forms an angle ranging between 0 and 45 degrees with a direction (21) of gas flow. An independent claim is also included for a method for cooling a fluid in a cooling device.

Description

The present invention relates to a device for cooling a gas flow and an associated cooling method. The invention will find its application for any use of a gas stream as a cooler in a heat exchanger more particularly in air conditioning systems, particularly in urban areas, in buildings but also for chillers or compressors, cooling machines or well directly to lower the ambient air in premises, factories. The invention is particularly adapted to "dry" heat exchangers said "dry cooler". For this purpose, air coolers or condensers are known. These machines consist of a heat exchanger and a means of ventilation. A fluid to be cooled or condensed circulates in tubes around which circulates the ambient air stirred by the ventilation means. The tubes are commonly filled with water, brine, oil or gas to condense. These systems operate by heat exchange. They are therefore configured to operate at the maximum of the thermal load as a function of a maximum ambient air temperature. However, extreme conditions occur for short periods of a year or a few hours during the summer days. At these times, the drycoolers and other condensers are not in working order.

It is then necessary to lower the temperature of the ambient air. For this, it is known that the humidification of the air causes a transfer of energy as the water evaporates thus lowering the temperature of the air. Various adiabatic cooling systems exist, such as the nebulisation of water by high or low pressure spray nozzles or the evaporation of water by evaporation panels. However, these systems have many drawbacks, including the risk of bacteriological proliferation during the dispersion of water in the gas stream, the need for water treatment, the deposition of limestone and the corrosion of the fluid circulation tubes and for evaporation panels more particularly a pressure drop on the gas flow and a rapid fouling accentuating this pressure drop, require an increase in the speed of rotation of the ventilation means causing a significant increase in the power consumption. There is therefore the need to propose a solution solving all or part of these disadvantages.

To this end, the present invention relates to a cooling device comprising means for cooling a gas stream, such as evaporating panels, placed in the gas stream, preferably upstream of a heat exchange means, and able to be mobile. to adapt their position according to the need for a cooling of the gas flow. More precisely, the cooling means can be positioned so as to vary the section of the application surface of the gas flow on the cooling means. When it is not necessary to cool the gas flow, the cooling means are arranged so that the section of the application surface of a gas flow on the panel (s) is low or zero. When the temperature of the ambient gas flow has to be lowered then the section of the application surface of the gas flow is increased. The invention makes it possible to extend the operation of these devices at all periods of the year without, however, achieving a pressure drop on the gas flow or an increase in excessive energy consumption. Similarly, the fact that the panels are in the open position when not in use reduces their fouling and thus increases their life. Other objects and advantages will become apparent from the following description which presents a preferred but non-limiting embodiment of the invention. It should first be recalled that the cooling device comprises at least one means for cooling a gas flow disposed in said gas flow comprising a material intended to be moistened, characterized in that the cooling means comprises at least a panel comprising said material to be moistened and configured to be movable so as to vary the cross-section of the gaseous surface of application on the panel. Preferred embodiments that are cumulative or alternative but nonlimiting are introduced below: the panel is capable of taking an extreme open position in which the section of the application surface of the gas stream is minimal, preferably zero. - The panel is oriented so that the plane containing the application surface 30 forms an angle between 0 ° and 45 ° with the direction of the gas flow preferably 0 and 20 °, preferably between 0 ° and 10 °, preferably 0 °. the panel comprises on a wafer intended to face the gas flow when the section of the application surface is minimal, preferably zero, a deflector configured to prevent the gas flow from passing through the panel. - The panel is adapted to take an extreme closed position in which the section of the application surface of the gas stream is maximum. - The panel is oriented so that the plane containing the application surface forms an angle between 45 ° and 90 ° with the direction of the gas flow, preferably between 60 ° and 90 °, preferably 90 °. - The panel is substantially parallelepiped shape. at least one panel is mobile in translation. - At least one panel is rotatable about an axis of rotation. - The axis of rotation of the panel is inscribed in a plane normal to the direction of the gas flow. it comprises a plurality of panels. - The axes of rotation of the panels are parallel. it comprises a motor and means for transmitting the movement of the motor to the plurality of panels. it comprises humidification means for the material to be moisturized arranged in the upper part of the panel. - It comprises at least one heat exchange means comprising a fluid to be cooled and around which circulates the gas flow, the heat exchange means being disposed in said gas stream downstream of the cooling means.

The invention also relates to a cooling method in a cooling device comprising: - the circulation of a gas stream, preferably around a heat exchange means, - the monitoring of the temperature of the gas stream, - the modification of the position of at least one panel so as to vary the section of its application surface to the gas flow as a function of the detected temperature of the gas flow. According to variants, the process is such that: the speed of the gas flow arriving on a heat exchange means is constant by adapting the speed of a ventilation means according to the section of the application surface of the gas flow on the panel. It comprises: - the actuation of humidification means of the material to be moistened with at least one panel when the detected temperature of the gas flow is greater than a predefined value; stopping the humidification means of the material to be moistened with at least one panel when the detected temperature of the gas flow is less than a predefined value. The accompanying drawings are given by way of example and are not limiting of the invention. They represent only one embodiment of the invention and will make it easy to understand. The figures illustrate a preferred mode of use of the invention in a fluid cooler. Figures 1 and 2 show a cooling device according to one embodiment of the invention. In Figure 1, the cooling means of the gas stream is in the closed position while in Figure 2, the cooling means of the gas stream is in the open position. Figure 3 is a view in section AA of Figure 1 showing the cooling means of the gas stream. Figures 4 and 5 are sectional views BB of Figure 2 according to a first embodiment of the invention. Figure 4 corresponds to an open position and Figure 5 corresponds to a closed position. Figures 6 and 7 are views of the type in section BB of Figure 2 according to a second embodiment of the invention. Figure 6 corresponds to an open position and Figure 7 corresponds to a closed position.

According to an embodiment shown in Figures 1 and 2, the invention consists of a casing 15 may be galvanized steel or stainless steel. The casing 15 receives two heat exchange means and two cooling means of the gas stream, all arranged symmetrically. However, according to the invention the envelope 15 may contain a single heat exchange means 1 and a single cooling means of the gas stream. The invention also extends to a device where the envelope 15 contains a cooling machine or any other element intended to use a cooled gas flow. As shown and without being in any way limiting, the heat exchange means 1 are arranged face to face and inclined with respect to one another so that their upper parts are further apart from each other than their In another possibility, the heat exchange means 1 can be arranged face to face in parallel and arranged in a vertical plane or in any other configuration. The space between the two heat exchange means 1 is an intermediate space 3 whose volume is defined to allow satisfactory air circulation. In addition, this intermediate space 3 allows access to the heat exchange means 1 through the interior 13 of the device. The heat exchange means 1 are conventionally referred to as air-cooler, "dry", or condenser. The heat exchange means 1 comprise an exchange surface formed by way of example of tubes that can be equipped with fins. The tubes are for example copper while the fins are aluminum. In the tube circulates a fluid such as water, glycol water, oil or a gas such as a refrigerant gas type R22, R134 or R404A ... The fluid to be cooled enters the tube of the heat exchange means 1 by an inlet of the fluid to be cooled 17. Preferably, this inlet 17 is located in the lower part of the heat exchange means 1. The fluid circulates in the tube around which flows a gas stream 10, the fluid temperature will gradually be decreased. The fluid leaves the heat exchange means 1 by an outlet of the cooled fluid 16 preferably disposed in the upper part of the heat exchange means 1. For a gas flow 10 to flow through and / or around the heat exchange means 1, the device preferably comprises ventilation means 4. These ventilation means 4 are arranged as an example in the upper part of the envelope 15.

Advantageously, the device according to the invention comprises at least one cooling means of the gas stream 10. The cooling means of the gas stream 10 is disposed or placed in the gas stream 10. It is understood by disposed or placed in the gas stream 10 that the cooling means is located in the path of the gas stream 10. Advantageously, the gas stream 10 is in movement in a main direction on which the cooling means is arranged. The cooling means of the gas stream 10 comprises at least one panel 2. The panel 2 advantageously has a parallelepiped shape. By way of example, the panel 2 has a width of 600 millimeters and a thickness of 150 millimeters.

According to a first possibility as represented in all the figures, the cooling means of the gas flow comprises a plurality of panels 2. However, it could be provided a single panel 2. The panel 2 comprises at least one material 9 intended to be moistened. By way of example, the panel 2 comprises impregnated cellulose corrugated paper sheets assembled together at different angles. Corrugated paper is a material that can be moistened.

It is particularly advantageous to choose a material that can reach a high level of humidification, for example from 85 to 90%, while limiting the risks of droplet entrainment out of the panel 2. A panel of the Celdek® type can be employee.

The cooling means of the gas stream 10 is intended to lower the temperature of the gas stream 10 before contact with the heat exchange means 1 or more broadly with its contact with an element to be cooled. For this, the cooling means is arranged in the gas stream 10, upstream of the heat exchange means 1.

More specifically, the heat exchange means 1 is disposed in the casing and the cooling means of the gas stream constitutes at least partly a face of the casing 15. Preferably, the casing 15 comprises at least one frame open to the level of which are positioned the cooling means of the gas flow. When the gaseous flow 10 passes through the cooling means of the gas flow and in particular of a humidified panel 2, there is a transfer of energy as the water evaporates causing a lowering of the temperature of the Gaseous flow 10. For example, a dry gaseous flow at a temperature of 30 ° C. and at 30% humidity which passes through a humidified panel 2 according to the invention stands out at a temperature of 20 ° C. and with 80% humidity. According to the invention, the cooling means of the gas flow is intended to be used, and therefore in function, a part of the total time of operation of the device. It has been shown that the means for cooling the gas flow is used between 10% and 20% of the time of use of the device.

The cooling means of the gas flow according to the invention is therefore movable so as to vary the cross section of the application surface of the gas flow on the panel 2. The cooling means is movable between two extreme positions: an open position ( Figure 2) and a closed position (Figure 1). Application surface 20 of the gas stream 10 on the panel 2, the surface of the panel 2 which is crossed by the gas stream 10. The section of the application surface 20 is understood as the surface of the surface of the application of the gas stream 10 in a plane normal to the direction of the gas flow 10. In the open position, the gas stream 10 directly contacts the outside 14 on the heat exchange means 1 advantageously without encountering the means of cooling the gas flow, more specifically without passing through a panel 2 of the cooling means of the gas stream. In the open position, the panels 2 are arranged so that the gas stream 10 passes through the open frame without crossing the panels 2. The panels 2 do not obstruct the opening of the frame. The panels 2 are arranged so that the section of the application surface 20 of the gas flow on the panels 2 is minimal.

According to one embodiment, the panels 2 comprise on at least one wafer and advantageously on their two longitudinal thickness slices a deflector 6. The deflector 6 is made of material that does not allow the gaseous flow to be introduced by way of example, stainless steel or in plastic. Thus, in the open position, the deflectors 6 face the gas flow 10, that is to say the plane of the deflector 6 is perpendicular to the direction 21 of the gas stream 10, and deviates it between the panels 2 to prevent that it crosses the panels 2 and that it clogs them. According to one embodiment of the invention illustrated in Figures 6 and 7, the cooling means comprises an intermediate baffle 6 '. The deflector 6 'is fixed between two panels 2. Advantageously, the baffle 6' is configured to facilitate the flow of the gas stream 10 between the panels 2 when they are in the open position, Figure 6. In the closed position, Figure 7, the deflector 6 'is configured so as to be in contact with the two panels 2 surrounding it, thus preventing the flow of gas flow 10 between the panels 2 but orienting it towards the section of the panels 2 so that the gas flow 10 passes through the 2. Preferably, in this case, the application area is 0% to 10% of the open frame area. In FIGS. 4 and 6, in the open position, the panels 2 are arranged so that the plane of the panel 2 in which the application surface 20 is embedded has an angle with the direction 21 of the gas flow 10 between 0 ° and 45 °. Preferably from 0 ° to 10 °. Preferably, in the open position, the panel 2 is in a position in which the application surface 20 is parallel to the direction 21 of the gas flow 10. In the closed position, the cooling means of the gas flow is arranged so that for the gas stream 10 comes into contact with the heat exchange means 1, the gas stream 10 necessarily traverses the cooling means of the gas stream. In the closed position, the panels 2 are arranged so that the gas flow 10 passes through the panels 2. The panels 2 obstruct the opening of the frame. The panels 2 are arranged so that the section of the application surface 20 of the gas flow on the panels 2 is maximum.

For preference, the application surface 20 represents of the order of 70 to 120% of the surface of the open frame.

In FIGS. 5 and 7, in the closed position, the panels 2 are arranged for the plane of the panel 2 containing the application surface 20 has an angle with the direction 21 of the gas flow 10 between 45 ° and 90 ° preferentially between 60 ° and 90 °. Preferably, in the closed position, the panel 2 is in a position in which the application surface 20 is perpendicular to the direction 21 of the gas flow 10. The direction of the gas flow 10 is understood to mean the main direction of the gas flow 21. Commonly, this direction will be normal to the open frame plan. In a conventional manner, the gaseous flow 10 is an air flow.

To humidify the material in the panel 2, the invention comprises humidification means shown in FIG. 3. It is advantageous for the humidification means to be arranged in the upper part of the panel 2 so that the water diffuses into the material on the entire height of the panel 2 aided by gravity. According to the invention, the humidification means are arranged outside the gaseous flow 10 so as to avoid any risk of splashing water into the gaseous flow 10. The humidification means advantageously comprise a water supply 7 bringing the water 18 in the upper part of the panel and a distributor 8 arranged between the water supply 7 and the material 9 to humidify the panel 2. The water supply 7 is advantageously by ramps and without pressure. The distributor 8, or distributor, is for example formed in the same material as the panel 2 but with different corrugations and extends over the entire surface of the upper edge of the panel 2. The distributor 8 is intended to distribute in a uniform manner the water 18 to reduce the dry areas on the panel 2 and thus increase the cooling efficiency of the panel 2. The amount of water supplied to the upper part of the panel 2 and / or the distributor 8 and / or the material chosen to form the panel 2 and / or the power of the ventilation means 4 are configured so that the panel 2 has a humidification rate of 85 to 90%. This reduces the risk of droplet entrainment out of the panel 2 thus reduces the risk of bacteriological proliferation and infection. Likewise, there is preferably no water 18 to be recovered in the lower part of the panel 2. If, however, water 18 reaches the lower part of the panel 2 and comes out of it, the cooling means of the gas flow comprises a recuperator (not shown), preferably in stainless steel, recovering water 18 to treat it and put it back into circulation without risk of bacteriological proliferation. The panels are movable in rotation and / or in translation. In the figures, the panels 2 are movable in rotation about an axis of rotation 19. Preferably, the axes of rotation 19 are parallel. The axes of rotation 19 are arranged at the open frame. The axes of rotation 19 extend in the same plane oriented perpendicular to the direction 21 of the gas stream 10. It could be envisaged that the panels 2 are movable in translation, for example by sliding, or that they have more complex mobilities .

The mobility of the panels 2 can be controlled either individually by a motor type servo motor or common way by a transmission means comprising rods 12 connecting the output of an engine to the different panels 2. Several configurations of the panels 2 are shown at Figures 4-5 and 6-7. In Figures 4 and 5, the panels 2 in the closed position (Figure 5) are said flat.

That is, the panels are aligned one after the other. The panels 2 and more precisely the application surfaces 20 are in the same plane. The open frame of the casing 15 allowing access of the gas stream 10 to the heat exchange means 1 is entirely covered with panels 2. The gas stream 10 must pass through the panels 2 to enter the envelope 15. In this case, for panels 600 millimeters wide and 150 millimeters thick, the distance to be provided is of the order of 630 millimeters. There is a use of the useful surface, that is to say the surface of the opening of the frame, of the order of 95%. In Figures 6 and 7, the panels 2 in the closed position (Figure 7) are said to be in parallel. That is to say that the panels 2 and more precisely the application surface 20 of each panel 2 are in separate parallel planes. Despite this inclination, the gas flow 10 flows through the panels 2 and not between them. In this case, for panels 600 millimeters wide and 150 millimeters thick, the spacing is 500 millimeters. There is a use of the useful surface of the order of 120%.

In the open position (FIGS. 4 and 6) the panels, and more specifically the application surface 20 of each panel 2, are preferably parallel to one another. The panels 2 are arranged so that the plane of the application surface 20 is substantially parallel to the direction 21 of the gas flow 10. It may also be that the plane of the application surface 20 is then perpendicular to the vertical longitudinal plane passing through the heat exchange means 1.

The device according to the invention can therefore be used all year regardless of the climatic conditions and in particular the temperature of the outside air. For this, the device as described above can be used according to the method described below.

The fluid to be cooled flows through the heat exchange means 1. The ventilation means 4 are in operation creating a gas flow 10 flowing from the outside 14 of the device to the inside 13 of the device where the gas flow 10 is snapped up. by the ventilation means 4. The device preferably comprises a detector of the temperature of the gas stream 10. If the temperature of the gas stream 10 exceeds a threshold, for example 20 ° C, control means drive the cooling means the gas flow and more particularly the panels 2 so as to place them in their closed position in which the gas flow 10 flows through the panels 2 before coming into contact with the heat exchange means 1. The water supply supply means 7 is actuated. Water 18 is discharged at the top of the panel 2, preferably at a distributor 8. The panel 2 is moistened. The ventilation means 4 are controlled so as to adapt their speed to the pressure drop caused for the closed position of the panels 2.

When the means for detecting the temperature of the gas stream 10 detect that the temperature of the gas stream 10 is lower than a threshold temperature, for example 20 ° C, the reverse process to that described above is implemented. Namely, the cooling means of the gas stream are moved so that the panels 2 take an open position, in which position the gas stream 10 does not pass through the panels 2 before coming into contact with the heat exchange means 1 The water supply of the panels 2 is stopped. The ventilation means 4 are controlled so as to adapt their speed to the open position of the panels 2.

REFERENCES 1. Heat exchange medium 2. Panel 3. Intermediate space 4. Ventilation medium 5. Servo motor 6. Deflector 7. Water supply 8. Dispenser 9. Material to be moistened 10. Gaseous flow 11. Supply rail in water 12. Rod 13. Inner 14. Outer 15. Shell 16. Cooled fluid outlet 17. Fluid inlet to be cooled 18. Water 19. Rotation axis 20. Application surface 21. Gaseous flow direction

Claims (18)

REVENDICATIONS1. Cooling device comprising at least one means for cooling a gas stream (10) disposed in said gas stream (10) comprising a material to be moistened (9), characterized in that the cooling means comprises at least one panel (2) comprising said material to be moistened (9) and configured to be movable, so as to vary the cross section of the application surface (20) of the gas stream (10) on the panel (2). 2. Device according to the preceding claim wherein the panel (2) is adapted to take an extreme open position in which the section of the application surface (20) of the gas stream (10) is minimal. 3. Device according to the preceding claim wherein the panel (2) is oriented so that the plane containing the application surface (20) forms an angle between 0 ° and 45 ° with the direction (21) of the gas stream. 4. Device according to any one of the two preceding claims wherein the panel (2) comprises on a wafer intended to face the gas flow (10) when the cross section of the application surface (20) is minimal, a deflector (6) configured to prevent the gas flow (10) from passing through the panel (2). 5. Device according to any one of the preceding claims wherein the panel (2) is adapted to take a closed end position in which the section of the application surface (20) of the gas stream (10) is maximum. 6. Device according to the preceding claim wherein the panel (2) is oriented so that the plane containing the application surface (20) forms an angle between 45 ° and 90 ° with the direction of the gas flow (21). 7. Device according to any one of the preceding claims wherein the panel (2) is of substantially parallelepiped shape. 8. Device according to any one of the preceding claims wherein the panel (2) is movable in translation. 9. Device according to any preceding claim wherein the panel (2) is rotatable about an axis of rotation (19). 10. Device according to the preceding claim wherein the axis of rotation (19) of the panel (2) is inscribed in a plane normal to the direction (21) of the gas flow. 11. Device according to any one of the preceding claims comprising a plurality of panels (2). 12. Device according to the preceding claim and claim 9 wherein the axes of rotation (19) of the panels (2) are parallel. 13. Apparatus according to any one of the three preceding claims comprising a motor and means for transmitting the movement of the motor to the plurality of panels (2). 14. Device according to any one of the preceding claims comprising means for moistening the material to be moistened (9) arranged in the upper part of the panel (2). 15. Device according to any one of the preceding claims comprising at least one heat exchange means (1) comprising a fluid to be cooled and around which circulates the gas stream (10), the heat exchange means being disposed in said flow gaseous downstream of the cooling means. 16. A method of cooling a fluid in a cooling device according to any one of the preceding claims comprising: - the circulation of a gas stream (10), - the monitoring of the temperature of the gas stream (10), - changing the position of at least one panel (2) so as to vary the section of its application surface (20) to the gas flow (10) as a function of the detected temperature of the gas stream (10). 17. Method according to the preceding claim wherein the speed of the gas stream (10) arriving on a heat exchange means (1) is constant by adapting the speed of a ventilation means (4) according to the section of the application surface (20) of the gas stream (10) on the panel (2). 18. A method according to any one of the two preceding claims comprising: - actuating humidification means of the material to be moistened (9) of at least one panel (2) when the detected temperature of the gas stream (10) is greater than a predefined value; - Stopping the humidification means of the material to be moistened (9) of at least one panel (2) when the detected temperature of the gas stream (10) is less than a predefined value.