EP3537089B1

EP3537089B1 - Cooling apparatus

Info

Publication number: EP3537089B1
Application number: EP19160861.1A
Authority: EP
Inventors: Paolo Ferraris; Massimo DE MARCO; Fabio Belloni
Original assignee: Althermo Srl
Current assignee: Althermo Srl
Priority date: 2018-03-06
Filing date: 2019-03-05
Publication date: 2021-04-28
Anticipated expiration: 2039-03-05
Also published as: ES2882068T3; EP3537089B8; EP3537089A1; PL3537089T3; DK3537089T3; IT201800003296A1

Description

The present invention relates to a cooling apparatus which comprises a micro-channel heat exchanger, according to claim 1.
Micro-channel heat exchangers have long been used in the automotive industry, in replacement of copper-aluminium mechanical condensers. In recent years, however, interest in micro-channel heat exchangers has grown, replacing the traditional tube-tab heat exchangers in industrial processes to cool or condense a working fluid, using the heat exchange with the air to reduce the temperature of the fluid. Among the devices that use a micro-channel heat exchanger, the dry cooler and the remote condenser exploit the outside air as secondary fluid, while the liquid, e.g. water, an aqueous solution containing ethylene glycol or a refrigerant, flows into micro-channel tubes and is brought from a first temperature to a second temperature, lower than the first. In the following description, cooling apparatus indicates an apparatus for cooling a fluid medium, gas or liquid, preferably a liquid.
Micro-channel cooling equipment is currently also in use in the field of HVAC air conditioning, cogeneration and refrigeration, for example as air condensers.
"Micro-channel" is usually intended as a channel with a hydraulic diameter (i.e. for the passage of a flow of liquid) smaller than about 3 mm, typically comprised between 1 mm and 2 mm in equipment for industrial use.
Micro-channel cooling equipment in industrial process cooling systems is equipped with fans and is often installed outdoors, for example on the roof of a building. In view of the fact that a plurality of heat exchangers is often necessary to cool working fluids, modular solutions can be advantageous in order to reduce the size of the cooling system.
Typically, the micro-channel heat exchanger has a substantially planar shape in which a main direction of extension can be defined. The Applicant has noted that if the heat exchanger is shaped so as to assume a closed or quasi-closed circular shape, the compactness of the apparatus for cooling or condensing a fluid, e.g. a dry cooler or condenser, increases, the thermal performance being the same.
WO 2008/136916 A1 shows a cooling apparatus that comprises a support structure that comprises a resting surface, a micro-channel heat exchanger arranged vertically on the resting surface, the heat exchanger comprising a plurality of micro-channel tubes and a fan.
The Applicant has considered a cooling apparatus which comprises a micro-channel heat exchanger which is circularly curved to form a circular opening of the upper outflow of air on which a fan is arranged. In a volume enclosed by the circularly curved heat exchanger, the inlet or outlet air entering/exiting the lower area of the heat exchanger has a lower speed than the speed of the air entering or exiting the upper portion of the heat exchanger, which is closer to the fan.
The Applicant has understood that the provision of an airflow guide element with a generally frusto-conical shape within the volume allows a substantially homogeneous distribution of air over the entire surface of the heat exchanger, from the bottom towards the top. This allows an overall greater heat capacity of the heat exchanger and therefore of the cooling apparatus.
In accordance with the present invention, a cooling apparatus is provided which comprises:

a support structure that comprises a resting surface;
a micro-channel heat exchanger arranged vertically on the resting surface, the heat exchanger comprising a plurality of micro-channel tubes arranged horizontally for the flow of a fluid and transverse air passages between the micro-channel tubes, wherein the heat exchanger is curved along a circular perimeter line so as to define a circular upper opening for the passage of air and a circular surface on the resting surface delimited by the heat exchanger (i.e. by the circular perimeter line);

a fan arranged on the air passage upper opening, and
an air flow guide element that comprises a guide body having a generally frusto-conical shape arranged centrally on the circular surface about a central axis.

Preferably, the guide body of the guide element has a side surface with a concave parabolic profile.
The Applicant has observed that a concave parabolic profile of the side surface of the frusto-conical guide body can further improve the flow of air which enters or exits the lower part of the airflow volume and which is subject to a considerable reduction of flow speed, as it is farthest from the point of aspiration or thrust.
Preferably, the fan is arranged on the upper air passage opening, so as to close this opening. The space enclosed by the support structure, in particular by the resting surface, the circularly curved heat exchanger and by the fan is substantially cylindrical in shape and will be indicated hereinafter as airflow volume.
Preferably, the guide body of the guide element is hollow.
The frusto-conical shaped guide body has a circular upper surface having an outer diameter. Preferably, the upper surface is perpendicular to the central axis.
Preferably, the fan is an axial fan which comprises a plurality of blades and a motor housed in a motor body arranged centrally in the upper air passage opening, the motor body having a (maximum) width in a direction parallel to the plane which comprises the upper surface of the guide body. The generally frusto-conical guide body is arranged so that its upper surface is arranged below and at the motor body, the upper surface having an outer diameter greater than or equal to the width of the motor body. Such a configuration, in particular if the guide body has a concave parabolic lateral profile, allows the airflow to be conveyed directly on the fan's wing profile, avoiding or reducing the air turbulence present in the zone in front of and next to the fan's motor body.
Especially in cooling systems which are installed outdoors, relatively high ambient temperatures, e.g. above 30°C, decrease the effectiveness of the air cooling.
Preferably, the cooling apparatus comprises a nebulizer device for the evaporative cooling of the surface of the heat exchanger. Preferably, the guide body is hollow and has an upper opening concentric to the central axis, the nebulizer device comprising:

a distribution conduit that extends inside the hollow body of the guide element along the central axis and passes through the upper opening of the hollow guide body, wherein the distribution conduit has an inlet that can be connected to a source of pressurized cooling liquid and an outlet, and
at least one diffuser conduit in fluid communication with the outlet of the distribution conduit, wherein the at least one diffuser conduit is positioned radially outside the guide body and comprises a plurality of nebulizer nozzles arranged in line along the at least one diffuser conduit and oriented so as to spray nebulized cooling liquid towards the heat exchanger.

In some embodiments, the guide element further comprises a tray for collecting possible excess nebulized water. The collection tray is arranged on the support surface of the support structure, in a radially external position with respect to the frusto-conical shaped body and comprises a raised edge along its perimeter. Preferably, the collection tray surrounds the guide body and is in contact with the lower end of the side wall of the guide body. Preferably, the heat exchanger is mounted onto the collection tray, along an inner line which is circular and concentric with respect to the edge of the tray. In this embodiment, the collection tray, of annular shape, has a greater outer diameter of the surface diameter defined by the outer circular line of curvature of the heat exchanger.
In a preferred embodiment, the guide body is hollow, the collection tray has an annular shape and the guide body and the collection tray are constructed in one piece.
Preferably, the fluid flowing inside the micro-channel tubes of the heat exchanger is a liquid.
In some embodiments, the cooling device is a dry cooler for cooling a liquid.

Brief description of the figures

Further features and advantages of the present invention will be more evident from the following description of some preferred embodiments thereof made with reference to the appended drawings. In such drawings,

figure 1 is a perspective view of a first embodiment of a cooling apparatus according to the present invention;
figure 2 shows the cooling apparatus of figure 1, in which the fan and the fixing elements to the support structure are omitted for the sake of clarity;
figure 3 is a perspective view of figure 2, partially in section, to show the volume enclosed by the heat exchanger and the fan;
figure 4 shows the guide element and the nebulizer device of the cooling apparatus of figures 1-3, with various elements from the support structure omitted for the sake of clarity;
figure 5 shows a partial section of the apparatus of the previous figures along a plane BB indicated in figure 1;
figure 6 is a schematic planar view of a parallel flow micro-channel heat exchanger;
figure 6A is an enlarged portion of the insert C of figure 6, which schematically shows the micro-channel structure.

Detailed description

With reference to figures 1 to 5, a cooling apparatus 10 comprises a support structure 11 which comprises an upper resting surface 12, on which is vertically mounted, i.e. substantially perpendicular to the resting surface 12 (z axis in the figures), a micro-channel heat exchanger 15. For example, the heat exchanger is fixed to the resting surface 12 with bolts.
The heat exchanger 15 is circularly curved, along a circular perimeter line, so as to delimit a circular surface on the resting surface 12 and to define a circular upper opening 27 for the passage of air (figure 2).
The micro-channel heat exchanger 15 comprises: a first manifold 20, arranged vertically with respect to the resting surface 12, for receiving an inlet fluid, and a second manifold 21, arranged in parallel with the first manifold 20 (and vertically with respect to the resting surface), for draining the fluid, a plurality of micro-channel tubes arranged horizontally and in fluid communication both with the first and with the second manifold. The micro-channel tubes are vertically distanced from each other to have a plurality of transverse air passages arranged between adjacent micro-channel tubes. The micro-channel tubes and the transverse air passages are not clearly visible in figures 1-3 and 5. The plurality of micro-channel tubes with the interposed air passages define a heat exchange region 14 which extends horizontally between the first and second manifold.
The heat exchanger has a length L of maximum vertical extension (z axis) from the resting surface 12. The heat exchange region 14 defines an inner heat exchange surface, which extends vertically around the circular surface.
The cooling apparatus 10 further comprises a fan 19 arranged on the upper air passage opening 27, so as to close this opening. The space enclosed by the support structure 11, in particular by the resting surface 12, by the circularly curved heat exchanger 15 and by the fan 19 has a substantially cylindrical shape and is indicated in the present description with airflow volume, in which the air, which enters through the air passages between the micro-channel tubes, is sucked towards the fan.
In the embodiment of the figures, a protection grid 49 is provided, arranged on the fan 19.
Figure 5 shows a partial section of the cooling apparatus 10 along a median transverse plane BB indicated in figure 1. The fan 19 is shown schematically, partly in section.
The fan 19 can be of the conventional type and comprises a plurality of blades 47 and a motor (not shown) for driving the blades, the motor being housed in a motor body 46. In the usual ways, the plurality of blades is connected to the motor body 46 which rotates about the axis of the impeller. The motor body 46 is centrally located in the upper air passage opening 27.
The fan 19 is mounted on a spacer element 18 which comprises a substantially cylindrical-shaped frame 18a. Preferably, the spacer element 18 comprises a support grid for the motor body fixed to the frame 18a, the support grid, of conventional type, being configured to facilitate the conveying of the air towards the blades (support grid, inside the frame 18a, not shown in figure 5 for the sake of clarity). The spacer element 18, in particular the frame 18a, is mounted on the heat exchanger 15. Preferably, the frame 18a has a diameter substantially equal to the diameter of the upper air passage opening 27.
The spacer element 18, i.e. the frame 18a on which the fan 19 is mounted, has a height such as to circularly enclose the motor body 46 and the blades 47 and to ensure that these elements are arranged above the heat exchange region 14. In this way the motor body 46, which often extends below the blades, avoids being located in a portion of the airflow volume affected by the heat exchange. Preferably, the motor body 46 and more preferably also the blades 47 are positioned at a height greater than the length L of vertical extension (in the figures along the z axis) of the heat exchanger 15.
In this embodiment, the airflow volume of substantially cylindrical shape is the space enclosed horizontally by the resting surface 12 and by the fan 19 and vertically by the circularly shaped heat exchanger 15 and by the frame 18a of the spacer element.
Preferably, the fan 19 is an axial fan, with which the air is sucked and sent in the same direction. The air flow is vertical, i.e. parallel to the impeller axis (i.e. z axis), and the air entering from the transverse air passages is conveyed to the outside by the fan through the air passage opening 27. The Applicant has realized that the apparatus according to the present invention can operate effectively also in a mode in which the fan 19 is configured to push air into the airflow volume, the air being conveyed towards the outside through the transverse air passages between the micro-channel tubes. Depending on the operating mode, the circular opening 27 is an opening for the outflow of air or the inflow of air. In known ways, the fan 19 can be set to push the air outside or inside the airflow volume, by setting the direction of rotation of the impeller and thus of the blades (setting the motor).
In the detailed description that follows, only for the sake of brevity, reference will primarily be made to a configuration in which the fan is configured to allow air to flow outward.
In the circularly curved heat exchanger, the first manifold 20 is adjacent to the second manifold 21 (figure 2). In the embodiment shown in the figures, the first and second manifold are arranged at a distance from one another, preferably comprised between 2 cm and 10 cm, defining a longitudinal opening which extends in the length of the manifolds. Preferably there is no contact between the two manifolds in order to avoid heat exchange between the fluid flowing in the first manifold 20 and the fluid flowing in the second manifold 21, typically at a lower temperature.
Preferably, a covering element 13 is arranged above the first and second manifold 20, 21 extending along the length of the manifolds and covering the longitudinal opening (figure 1). The covering element 13 serves to close the longitudinal opening between the manifolds so as to circularly close the airflow volume and render the aspiration of the air towards the fan 19 more efficient.
With reference to figures 1 and 5, the heat exchanger 15 and the fan 19 mounted on the spacer element 18 are attached to each other and to the support structure 11 by means of fixing elements 16, 17 (more clearly visible in figure 1). In particular, a plurality of tie-rods 16 fixes, e.g. by means of fixing bolts, the heat exchanger to the support structure 11 and a respective plurality of connection plates 17 fixes the heat exchanger 15 to the spacer element 18, in particular to the frame 18a, e.g. by means of fixing bolts. In the non-limiting example of figure 1, the connection plates 17 are plates for orthogonal-transverse connection, transversely connected to a lower flange of the frame 18a of the spacer element 18 and orthogonally to a respective tie-rod 16 for the fixing to the support structure 11. The connection plates 17 can be equipped with a free vertical portion that comprises a through hole for hanging and transporting the cooling apparatus. It is understood that the present invention is not limited to a particular fixing configuration.
The construction of the micro-channel heat exchanger can be of a conventional type. Preferably, the heat exchanger has a parallel flow configuration. Figure 6 schematically shows a typical construction of a parallel flow micro-channel heat exchanger. Figure 6A is an enlarged portion of the insert C of figure 6, which schematically shows the micro-channel structure. The heat exchanger 15 comprises a plurality of micro-channel tubes 25, each tube 25 having two ends (not indicated) connected, respectively, to the first and to the second manifold 20, 21 so as to be in fluid communication with the first and second manifold 20, 21.
Typically, in conventional micro-channel heat exchangers, the maximum thickness of the heat exchanger along a direction perpendicular to the main extension is approximately 2 cm to 10 cm, and is often defined by the transverse section of the distribution manifolds of the circulating fluid.
The micro-channel tubes 25 are arranged horizontally substantially in parallel to each other. The first and second manifolds 20, 21 are arranged in parallel with respect to each other and substantially perpendicular to the micro-channel tubes 25. Each micro-channel tube comprises a plurality of micro-channels, within which the fluid flows. Preferably, the micro-channel tubes are flat, for example of a thickness of about 3 mm, and each comprising a plurality of micro-channels with a width transverse to the flow of from 1 mm to 6 mm. The tubes can be welded to the manifolds by brazing or by casting.
Preferably, the heat exchanger 15 comprises a plurality of tabs 26, which are arranged in the air passages between adjacent tubes 25 and in contact therewith. Preferably, each tab 26 extends in parallel to the micro-channel tubes, substantially covering the length of the micro-channel tubes. The tabs are preferably welded between the micro-channel tubes by brazing. In one embodiment, the tabs 26 are Louver-type tabs.
With reference again to figures 1-5, the first manifold 20 has an inlet opening 22 for the inlet of a fluid and a first plurality of outlet openings (not visible) arranged along its length, at the first ends of the micro-channel tubes for putting the first manifold in fluid communication with the micro-channels of each tube of the plurality of tubes. The fluid flows along the micro-channels along parallel flow paths. The second manifold 21 has an outlet opening 23 for draining the fluid and a second plurality of inlet openings (not visible) respectively to the first plurality of outlet openings, arranged along its length, at the second ends of the micro-channel tubes.
Preferably, the inlet opening 22 for the inlet of fluid and the outlet opening 23 for the outflow of fluid are arranged at one end of the respective manifold 20, 21. In the embodiment shown in figures 1-5 (more clearly visible in figure 3, which shows the heat exchanger in a partial section), the support structure 11 comprises a first and a second through opening 28a and 28b for the insertion of the lower end of the respective manifold 20, 21 which comprises the respective opening 22, 23.
In the case of cooling a working fluid and in the air condensers for HVAC, the heat exchanger is typically with an open-loop flow. However, the present invention envisages that the heat exchanger can be a closed-loop flow.
In operating mode, the first manifold 20 is connected, via the inlet opening 22, with an inlet conduit for the inflow of fluid and the second manifold 21 is connected, via the outlet opening 23, with an outlet conduit for the outflow of fluid (inlet and outlet conduits not shown in the figures).
The fluid can be a liquid, e.g. hot water, which must be cooled. In this case, the cooling apparatus, e.g. dry cooler, can be part of a cooling or temperature control system for industrial processes wherein the water is cooled by the airflow. For example, the high-temperature water enters the first conduit 20 of the heat exchanger and exits the second conduit 21 at a lower temperature.
If the fluid is a liquid coolant, the cooling apparatus 10 can function as an air condenser.
The air enters from the outside through the tabs 26 and, with the fan motor on, is conveyed toward the exit, i.e. the upper air passage opening 27, through the blades 47 of the fan 19.
Preferably, the micro-channel tubes 25, the tabs 26 and, more preferably, the manifolds 20 and 21 are made entirely of aluminium.
Micro-channel heat exchangers typically have a planar configuration, i.e. they have a main direction of extension arranged on a plane, as in the example of figure 6. In order to obtain a circular configuration, the planar micro-channel heat exchanger is bent circularly, along a circumferential line so as to bend the plurality of micro-channel tubes, approaching the first manifold 20 to second manifold 21. When the exchanger is mounted on the resting surface 12, the circumferential bending line defines the perimeter of the circular surface of the generally cylindrical airflow volume.
According to the present invention, the cooling apparatus 10 comprises an airflow guide element 40 arranged in the airflow volume and configured to guide the air, which enters or exits through the spaces (preferably tabbed) interposed between the micro-channel tubes, towards the fan or coming from the fan.
The airflow guide element has the general function of optimizing the outflow/inflow of outgoing/incoming air between the micro-channel tubes.
The guide element 40 comprises a guide body 40a of a generally truncated cone shape, preferably with a circular base. The truncated cone body is arranged on the resting surface 12, substantially centrally with respect to the circular surface delimited by the heat exchanger, about a central axis A (along axis z). Preferably, the truncated cone guide body 40a has a lateral surface 40b of rotation having concave parabolic profile. The concave parabolic profile is in relation with a transverse section in the yz plane perpendicular to the resting surface 12 and passing through the central axis A. The concave parabolic profile has a progressive increase in the transverse section in a plane yz of the body 40a from an upper end of the lateral surface 40b to its lower end, on the base of the guide body 40a.
The parabolic profile of the lateral guide body surface is concave with respect to the airflow entering (or exiting) through the air passages of the heat exchanger.
Preferably, the frusto-conical guide body 40a has a substantially circular upper surface and a lower surface, concentric to the upper surface, substantially circular.
Preferably, the axis of the impeller of the fan 19 is on the central axis A and therefore the motor body 46 is approximately centred on the central axis A. In a plane which passes through the motor body and is perpendicular to the central axis A, the motor body occupies a motor area centrally arranged in the upper air passage opening 27. The motor area of the motor body can be represented by the width of the motor body 46 in a direction perpendicular to the central axis A. With width is intended the maximum width of the motor body.
Preferably, the guide body 40a is arranged so that the upper surface of the guide body is arranged below and at the motor area of the motor body. In this way, the airflow towards the fan continues upwards along the concave parabolic surface and, without being obstructed by the air turbulence created by the motor body in action, reaches the wing profile of the fan. This applies also if the fan's motor is operated so as to push the air towards the inside of the airflow volume.
Preferably, the upper surface of the guide body has an outer diameter greater than or equal to the width of the motor body in a direction lying in a plane parallel to the upper surface, in the embodiment of the figures in a direction perpendicular to axis A. In some embodiments, the outer diameter of the upper surface is approximately equal to the width of the motor body.
In the preferred embodiments, the guide body 40a of the guide element 40 of generally frusto-conical shape is hollow and has an upper opening 43 concentric to the central axis A. The hollow guide body has a lower opening on the resting surface 12. Preferably, the lower end of the side surface 40b delimits the lower opening at the base of the guide body (partially visible in figure 3) which is arranged on the resting surface 12. In the embodiment of the figures, the upper and lower surfaces of the hollow guide body 40a are generally ring shaped.
In one embodiment, the guide body has a height H of 1050 mm, an upper surface with an outer diameter of about 160 mm and a lower surface with a diameter of about 1080 mm.
Preferably, the guide body 40 has a height H greater than or equal to 0.8xL, with L being the maximum vertical extension of the heat exchanger 15 from the resting surface 12. More preferably, the height of the guide element 40 is comprised between 0.8xL and L. However, it is to be understood that, with a suitable sizing of the spacer element 18, the height of the guide element 40 could be higher than L. In some embodiments, the height H of the guide element is comprised between 0.8xL and 1.1xL.
The Applicant has noted that, especially in cooling systems which are installed outdoors, relatively high ambient temperatures, e.g. higher than 30°C, decrease the air cooling effectiveness.
In the preferred embodiments, the apparatus comprises a nebulizer device 30 for the evaporative cooling of the air inside the cylindrical airflow volume through the evaporation of a cooling liquid, preferably water, in contact with the air. In such embodiments, the guide body 40a is hollow. The nebulizer device 30 comprises a distribution conduit 39 which extends vertically from the resting surface 12 and is arranged substantially centrally in the circular surface delimited by the heat exchanger 15. The distribution conduit 39 extends inside the hollow guide body 40a along the central axis A. The hollow guide body 40a of the guide element 40 is concentric to the distribution conduit 39, which passes through the upper opening 43 of the guide body.
The distribution conduit 39 has a lower inlet opening 48 (figure 5) for the introduction of pressurized water, which can be at room temperature or refrigerated, from a source (e.g. tank or water mains) external to the cooling apparatus and not shown in the figures. The distribution conduit further comprises an upper outlet opening for the pressurized water.
The distribution conduit 39 is mounted on a rotary joint 38, for rotation about the central axis A. The rotary joint 38 is in turn mounted in a central through hole (not indicated) which from the resting surface 12 passes through the support structure 11. The rotary joint 38 is motorized or activated by the water pressure, in known ways.
The distribution conduit is connected to at least one diffuser conduit provided with a plurality of nebulizing nozzles. The at least one diffuser conduit is arranged vertically, in parallel with the distribution conduit and spaced therefrom, in a radially external position to the guide body. The at least one diffuser conduit rotates in an integral manner with the distribution conduit along a circular line while the distribution conduit rotates about itself. Preferably, the at least one diffuser conduit is rigidly connected to the distribution conduit. Preferably, the at least one diffuser conduit is connected to the distribution conduit by means of a connection conduit and is suspended from the latter. The circular line of rotation of the at least one diffuser conduit is radially external to the lower surface of the guide body and radially internal to the circular perimeter line that delimits the airflow volume on the resting surface 12.
In the embodiment of the figures, the distribution conduit 39 is connected to a first and a second diffuser conduit 32a and 32b, arranged vertically, in parallel with the distribution conduit 39, and spaced from it so as to be arranged radially outside the guide body 40a. The diffuser conduits 32a, 32b are connected to the distribution conduit 39 by means of a transverse connection conduit 33, preferably arranged horizontally. To facilitate rotation, the diffuser conduits are suspended from the connection conduit 33.
Each diffuser conduit comprises a plurality of nebulizer nozzles 35 arranged along the respective diffuser conduit and oriented so as to spray nebulized water (in droplets typically a few microns in diameter) toward the heat exchanger 15. In particular, nebulized water is sprayed on the inner heat exchange surface of the heat exchanger 15, which faces and encloses the airflow volume. Preferably, the nebulizer nozzles 35 are arranged in a line along the respective diffuser conduit 32a, 32b.
The distribution conduit 39 has a length greater than the height H of the hollow body 40a so as to have an upper water outlet opening arranged above the guide element 40 for the connection with the transverse connection duct 33, and then with the diffuser conduits 32a, 32b.
In some embodiments, the length of the conduit 39 is less than or equal to the length L of the heat exchanger, preferably comprised between 0.9xL and L. However, it is to be understood that with a suitable sizing of the spacer element 18, the length of the distribution conduit could be greater than L. In some embodiments, the length of the distribution conduit is comprised between 0.9xL and 1.2xL and is greater than H (guide body height).
Preferably the diffuser conduits 32a, 32b are arranged radially symmetrically with respect to the distribution conduit 39 and therefore to the central axis A of rotation. The construction is "carousel style" and the diffuser conduits 32a, 32b, suspended from the connection conduit 33, rotate along a circular line concentric to the distribution conduit 39, radially external to the guide element and radially internal to the circular perimeter line of the circular surface delimited by the heat exchanger 15.
The length of the diffusion conduits 32a, 32b is preferably selected so that the conduits extend vertically to spray the inner surface of the heat exchange region 14, preferably the entire inner surface.
Pressurized water, for example at a pressure between 1 and 10 bars, is pushed along the distribution conduit towards the upper outlet opening to exit from the nozzles 35 in the form of nebulized sprays. For example, the distribution conduit 39 is connected to a compressor (not shown).
In one embodiment, the cooling apparatus has a total height of about 1.90 m, the length L of maximum vertical extension of the heat exchanger is about 1.30 m and the diameter of the upper circular air passage opening (and therefore of the circular resting surface delimited by the exchanger) is about 1.00 m.
Preferably, the guide element 40 further comprises a collection tray 41 for collecting any excess nebulized water. The collection tray 41 comprises a raised edge 42 along its perimeter and is arranged on the resting surface 12 of the support structure 11, in a radially external position to the frusto-conical guide body 40a. In the embodiment of the figures, the collection tray 41, which is mounted on the resting surface, surrounds and is in contact with the lower end of the side wall 40b of the guide body 40a.
In one embodiment, the collection tray has an annular shape. The collection tray 41 comprises a drainage opening (not visible), preferably arranged in an intermediate radial position between the edge 42 and the perimeter of the body 40a. The drainage opening is arranged at a through opening of the support structure 11 so as to allow water to drain outside of the cooling apparatus.
Preferably, the guide body 40a is hollow and the guide body and the collection plate 41 are constructed in one piece, preferably made of a plastic material, for example ABS (acrylonitrile-butadiene-styrene). For example, the hollow guide body integrated with the collection tray can be made by thermoforming. In this embodiment, shown in the figures, the collection tray 41 forms the base of the guide body 40a.
Preferably, the heat exchanger is arranged on the collection tray 41, mounted along an inner circular line and concentric with respect to the edge 42 of the collection tray 41. In this embodiment, the collection tray 41 has a diameter greater than the diameter of the surface defined by the outer circular line of curvature of the heat exchanger 15. The collection tray 41 comprises two through holes (not visible in figure 4 because they are hidden by the raised edge 42) at the holes 28a, 28b for the insertion/assembly of the first and second manifold 20, 21 in the support structure 11.
The nebulizer device can be configured to be activated in the case of relatively high ambient temperatures, for example higher than 30°C, and to be deactivated when the temperature falls below a threshold value. For this purpose and in known ways, the activation/deactivation of the nebulizer device can be controlled by a central control unit to which an ambient temperature detection system is connected.
Naturally, those skilled in the art may make further modifications and variants to the above-described invention with the purpose of meeting specific and contingent application needs, variants and modifications in any case falling within the scope of protection as defined by the successive claims.

Claims

Cooling apparatus (10) that comprises:
- a support structure (11) that comprises a resting surface (12);

- a micro-channel heat exchanger (15) arranged vertically on the resting surface (12), the heat exchanger comprising a plurality of micro-channel tubes (25) arranged horizontally for the flow of a fluid and transverse air passages (26) between the micro-channel tubes, wherein the heat exchanger is curved along a circular perimeter line so as to define a circular upper opening (27) for the passage of air and a circular surface on the resting surface (12) delimited by the heat exchanger (15);

- a fan (19) arranged on the air passage upper opening (27), and

- an air flow guide element (40) that comprises a guide body (40a) having a generally frusto-conical shape arranged centrally on the circular surface about a central axis (A).
Cooling apparatus (10) according to claim 1, wherein the body (40a) of the guide element (40) has a lateral rotation surface (40b) having a concave parabolic profile.
Cooling apparatus (10) according to claim 1 or 2, wherein the body (40a) is hollow and has an upper opening (43) concentric to the central axis (A).
Cooling apparatus (10) according to one of the preceding claims, wherein the micro-channel heat exchanger (15) comprises:
- a first manifold (20) arranged vertically for receiving an inlet fluid;

- a second manifold (21) for draining the fluid, arranged in parallel to the first manifold (20), wherein
the plurality of micro-channel tubes (25) is arranged horizontally between the first (20) and the second manifold (21) and in fluid communication both with the first and with the second manifold, the micro-channel tubes (25) of the plurality being distanced vertically from each other, and
the micro-channel tubes of the plurality of micro-channel tubes (25) are curved along the circular perimeter line and the first manifold (20) and the second manifold (21) are arranged adjacent to one another.
Cooling apparatus (10) according to one of the preceding claims, wherein the micro-channel heat exchanger (15) further comprises:
- a plurality of tabs (26) arranged in the transverse air passages between adjacent micro-channel tubes (25).
Cooling apparatus (10) according to one of the preceding claims, wherein:
- the fan (19) is an axial fan that comprises a plurality of blades (47) and a motor housed in a motor body (46) positioned centrally in the circular air passage opening (27), and

- the guide body (40a) having a generally frusto-conical shape has an upper surface arranged below and at the motor body (46) and having an outer diameter that is greater than or equal to the width of the motor body in a direction parallel to the plane that comprises the upper surface.
Cooling apparatus (10) according to one of the preceding claims, wherein the fan (19) is mounted on a spacer element (18) that comprises a substantially cylindrically shaped frame (18a) arranged on the heat exchanger (15), the frame having a height such as to enclose the motor body (46) and the plurality of blades (47) and to position the motor body (46) at a height greater than the maximum extension length of the heat exchanger (15) in the vertical direction.
Cooling apparatus (10) according to one of the preceding claims, when dependent on claim 3, which further comprises a nebulizer device (30) that comprises:
- a distribution conduit (39) that extends inside the hollow body (40a) of the guide element (40) along the central axis (A) and passes through the upper opening (43) of the hollow body, wherein the distribution conduit (39) has an inlet that can be connected to a source of pressurized cooling liquid and an outlet, and

- at least one diffuser conduit (32a, 32b) in fluid communication with the outlet of the distribution conduit (39), wherein the at least one diffuser conduit (32a, 32b) is positioned radially outside the guide body (40a) and comprises a plurality of nebulizer nozzles (35) arranged in line along the at least one diffuser conduit and oriented so as to spray nebulized cooling liquid towards the heat exchanger (15).
Cooling apparatus (10) according to claim 8, wherein the distribution conduit (39) is configured to rotate about the central axis (A) imparting a rotation to the at least one diffuser conduit (32a, 32b) along a circular line radially external to the guide body (40a) and radially internal and concentric with respect to the circular perimeter line, the at least one diffuser conduit (32a, 32b) being arranged in parallel to the distribution conduit (39).
Cooling apparatus (10) according to one of claims 8 or 9, wherein the at least one diffuser conduit comprises a first (32a) and a second diffuser conduit (32b), connected to the distribution conduit (39) and arranged in parallel thereto, each diffuser conduit comprising a plurality of nebulizer nozzles (35) arranged along the respective diffuser conduit and oriented so as to spray nebulized cooling liquid towards the heat exchanger (15).
Cooling apparatus (10) according to claim 10, wherein the first and the second diffuser conduit (32a, 32b) are rigidly connected to the distributor conduit (39) through a transverse connection conduit (33) and are arranged suspended from the transverse connection conduit (33) radially symmetrically with respect to the distribution conduit (39).