AIR CONDENSER
The invention relates to a cylindrical air condenser having a heat exchanger which has a cylindrical or polygonal shape that develops in a vertical direction (Z) from a base or bottom to a top, and a suction device provided with a motorized fan housed in a frame arranged on the top of the heat exchanger. The cylindrical condenser includes a distributor element, housed inside the heat exchanger coaxially therewith. The distributor element has a plurality of conduits arranged coaxially one to the other, and have a progressively increasing height from the top to the bottom of the heat exchanger and a progressively decreasing transversal dimension. The configuration of the distributor element is such that, starting from the top towards the base of the heat exchanger, a plurality of through openings (A1-A6) whose areas are nominally identical are defined therein in the vertical direction (Z).
The present invention relates in general to the field of refrigeration systems and of air conditioning apparatuses. More particularly, the invention relates to a vertical discharge air condenser for such systems and apparatuses.
BACKGROUNDRefrigeration and air conditioning systems use refrigerant circuits based on the circulation of a fluid between an evaporator and a condenser connected by special pipes, in which the fluid exiting from the evaporator is fed towards the condenser by means of a compressor and the fluid coming out from the condenser recirculates towards the evaporator passing through a rolling valve.
In a refrigeration and conditioning system the condenser is typically a unit located outside the room to be cooled, which exploits the air of the surrounding environment as a means for cooling the gas circulating in the refrigeration circuit. The air flow through the condenser depends on the configuration of its structure. For example, capacitors are known in which the air flow is substantially horizontal, i.e. parallel to the ground or to a support plane, and condensers in which the air flow is axial or vertical, i.e. perpendicular to the ground or to a support plane. Depending on the required cooling capacity, several air condensers can be placed side by side and connected to each other.
An axial or vertical flow condenser typically comprises a cylindrical or polygonal heat exchanger with finned walls, which rests on a base and is surmounted by a suction device provided with a motorized fan. The suction device creates in the heat exchanger a depression such as to axially suck a flow of air which enters transversely or radially through its finned walls. The air removes heat by convection from the finned walls of the heat exchanger, cooling the gas flowing in the refrigerant circuit housed therein and allowing condensation.
U.S. Pat. No. 8,627,670 describes an example of a vertical discharge air condenser of this type, in which the walls of the heat exchanger comprise bundles of coplanar micro channels crossed by a refrigerating fluid. The bundles of micro ducts, connected at their ends by inlet/outlet conduits that act as uprights, are arranged parallel in the vertical direction and have spaced fins through which the air is sucked. The use of micro conduits allows to obtain a large heat exchange surface whilst limiting the overall weight and the overall size of the heat exchanger and therefore of the condenser.
Heat exchangers that employ micro conduits are typically constructed using panels consisting of a pair of conduits for feeding a refrigerant gas between which bundles of micro conduits alternated with fins transversely extend, which are suitably curved or bent to realize the perimeter walls of a chamber with a generally cylindrical or polygonal shape. Depending on the configurations of the heat exchanger and of the required cooling capacity, the panels may be not only arranged adjacent to each other in a circumferential or perimetral direction, but also vertically overlapped, creating a tower structure surmounted by the suction device, whose height depends on the number of overlapping panels as well as on their respective heights.
It is known that, given a cross section of the heat exchanger, the power of the suction device must be chosen according to the height of the heat exchanger itself. It is known that, for allowing the passage of an air flow transversely through the walls of the heat exchanger throughout its whole height, it is necessary to generate a depression level such to compensate for the pressure drop distributed in the vertical direction of the same heat exchanger.
In a too high structure for the suction capacity of the motorized fan, it may happen that, due to distributed pressure drop, near the base of the heat exchanger there is not enough air flow to allow an adequate exchange of thermal energy in the form of heat, or that there is no air flow. It follows that the surface of the heat exchanger is not exploited optimally and/or entirely, which penalizes the efficiency of heat exchange.
The maximum height of the condenser is therefore limited by the airflow that may be sucked by the motorized fan of the suction device provided for it.
An increase of the rotation speed of the motorized fan in order to increase the flow rate of the air flow that may be sucked involves a greater noise level of the condenser as a whole, i.e. of the heat exchanger and of the suction device mounted thereon, which is not acceptable or generally allowed by present regulations.
The present regulations also limit the maximum power of electric motors that can be used in suction devices.
In an attempt to equalize the flow rate of air along the walls of the heat exchanger, and in particular to make substantially constant the speed of airflow, it has been proposed to arrange along its walls perforated panels comprising a plurality of through apertures whose passage sections increase progressively from a minimum value to a maximum value from the top to the bottom or to the base of the heat exchanger itself. The air flow sucked crosswise through the walls of the heat exchanger is thus regulated by the through openings obtained in the panels and then conveyed vertically towards its top.
The use of these panels, however, has the disadvantage of generating pressure drops concentrated in correspondence of their through openings, which penalizes the heat exchange efficiency of the heat exchanger.
Furthermore, the presence of the panels along the walls of the heat exchanger undesirably increases the noise of the air condenser as a whole.
SUMMARY OF THE INVENTIONThe technical problem posed and solved by the present invention is therefore that of supplying a vertical discharge air condenser that allows to overcome the aforementioned drawbacks with reference to the prior art.
This problem is solved by an air condenser according to claim 1.
Preferred features of the present invention are defined in the dependent claims.
An idea of solution underlying the invention is that of inserting inside the heat exchanger, which is part of a vertical discharge air condenser, a regulating member or distributor of the air flow sucked by the suction device, wherein said regulator or distributor element comprises a plurality of conduits arranged coaxially to each other in the vertical direction and having a progressively increasing height from the top to the bottom of the heat exchanger and a progressively decreasing diameter. The configuration of the conduits is such that, going from the top towards the bottom or the base of the heat exchanger, a plurality of through openings having nominally identical areas are defined within it in the axial or vertical direction.
The configuration of the distributor element and the arrangement of the openings passing in the vertical direction is such to equalize the flow rate from the base to the top of the heat exchanger, minimizing concentrated pressure drops. Experimental tests allowed to verify that air speed near the walls of the heat exchanger is substantially constant from its base to its top, thus allowing to use its entire radiating surface and therefore obtaining a high thermal exchange efficiency. It is thus possible to take full advantage of the benefits of the vertical configuration of an air condenser and to create higher structures with the same cross section of the heat exchanger, whose heat exchange efficiency is overall greater than that of the vertical flow condensers known in this field.
According to an embodiment of the invention, at the ends of the conduits of the distributor element directed towards the bottom or base of the heat exchanger, flow regulators may be associated, for example with lamellae. This offers the advantage of allowing variations and fine adjustments of the air passage areas in order to optimize flow along the walls of the heat exchanger.
Other advantages and characteristics, as well as the way of use of the present invention will appear from the following detailed description of some embodiments thereof, presented by way of a non-limiting example.
Reference will be made to the figures of the attached drawings, in which:
Making reference to
The air condenser 100 according to the invention comprises a heat exchanger 110 which has a cylindrical or prismatic shaped structure which develops in the vertical direction Z.
In the illustrated embodiment, the heat exchanger 110 has, for example, an octagonal prismatic shape comprising two walls, respectively, which are constituted by a shaped panel 111 comprising a pair of inlet/outlet conduits 112, 113 for a refrigerating fluid, which extend in the vertical direction Z and act as uprights, and a plurality of bundles or turns of micro-channels alternated with fins along the vertical direction Z (not shown). The panels which form the walls 111 are folded so as to form four sides of the perimeter of an octagon. The heat exchanger 110 is formed by abutting two walls 111 in the perimeter direction.
It will be understood that this configuration of the heat exchanger 110 is not binding for the invention, but it is advantageous because, as it is known, the use of micro-channels allows to obtain a large heat exchange surface without resulting in large size of the heat exchanger.
In the illustrated embodiment, the heat exchanger 110 has a modular structure comprising two pairs of superimposed panels in the vertical direction Z. It will be understood that this configuration of the heat exchanger 110 is not binding for the invention.
The condenser 100 further comprises a suction device 120 provided with a motorized fan 121 housed in a frame 122 having a generally cylindrical shape. This suction device 120 is disposed on the top of the heat exchanger 110. The frame 122 surmounts the heat exchanger 110 and is open at the bottom to allow fluid communication with it. A safety grid 123 is arranged between the frame 122 and the heat exchanger 110.
According to the invention, the capacitor 100 further comprises a distributor element 130 with controller function F of an air flow sucked by the suction device 120 transversely through the walls of the heat exchanger 110 and then in the vertical direction Z. The distributor element 130 is housed inside the heat exchanger 110 coaxially with it.
The distributor element 130 is constituted by a plurality of conduits coaxially arranged one to the other. These conduits, which in the illustrated embodiment are five, for example, and have a cylindrical shape, respectively indicated by the reference numerals 131a-131e, have a progressively increasing height from the top to the bottom of the condenser 100 and a progressively decreasing transversal dimension.
With reference to
More particularly and with reference to the illustrated embodiment, between the frame 122 of the suction device and the first one of the conduits 131a, and between the latter and the subsequent conduits 131b-131e of the distributor element 130 are defined in the vertical direction Z, of the through openings A1-A5 through which the air flow F, passing through the walls of the heat exchanger 110, is axially sucked. The distributor element 130 is spaced from the bottom of the heat exchanger, whereby a further through opening A6 coincides with the cross-section of the conduit 131 and with a smaller transverse dimension.
The arrows in
With particular reference to
In the light of the foregoing, it will be understood that, proceeding vertically from the top towards the bottom of the heat exchanger 110, the total passage area of the section for the air flow F sucked transversely through its walls increases discretely and results from the sum of the areas of the through openings that, at a certain distance from the top of the heat exchanger 110 itself, face towards its bottom.
Chosen a “n” number of sectors, the overall height “H” of the heat exchanger 110 is subdivided into n sectors Hc1-Hcn having nominally the same height. In the illustrated embodiment there are for example six sectors, Hc1-Hc6.
Starting from the top and proceeding towards the bottom of the heat exchanger 110, the conduits 131a-131e extend respectively to the boundary between a sector Hc(i) and the subsequent sector Hc(i+1). The number of conduits is equal to the number of sectors less than one, for which the last sector Hcn is completely free from the distributor element 130.
The calculation of the plan dimensions of the conduits 131a-131e is carried out on the basis of the areas of the through openings. Being “Apt” the area of the opening passing through the interface between the suction device 120 and the heat exchanger 110, which represents the total or overall passage area of the air flow sucked by the suction device 120, the area of the generic through opening “Ax” is calculated according to the following formula:
Ax=Apt/(number of sectors−1)
The through openings are therefore nominally identical with each other.
Once the nominal area of the through openings, that are six, A1-A6, in the illustrated embodiment, is known, it is possible to determine the transverse dimensions of the conduits 131a-131e, for example their diameters in the illustrated embodiment.
It will be understood that the actual dimensions of the distributor element 130 depend on the manufacturing and assembly tolerances of its parts.
According to one embodiment of the invention, the conduits 131a-131e are arranged so as to be offset from each other in the vertical direction Z, which favors the formation of air vortexes by the fan of the suction device 120. More particular the duct 131a having the larger transverse dimension and the lower height is arranged in the vicinity of the top of the heat exchanger 110 immediately under the frame 122 of the suction device 120. The other conduits 131b-131e are progressively spaced from the first conduit 131a and one from the other in the vertical direction Z.
With particular reference to the longitudinal section of
As it is known, the suction device 120 generates inside the heat exchanger 110 a depression such as to suck the air flow F through the finned walls from the outside. The configuration of the distributor element 130 and the arrangement of the conduits 131a-131e and their openings A1-A6 in the vertical direction Z is such to equalize the flow rate F from the bottom to the top of the heat exchanger 110 minimizing the concentrated pressure drops.
Experimental tests allowed to verify that the air speed near the walls of the heat exchanger 110 is substantially constant from its bottom up to its top, thus allowing to exploit its entire radiating surface and therefore to obtain a high thermal exchange efficiency.
Comparative experimental tests allowed to verify that the air speed in the vicinity of the walls of the heat exchanger 110 is about twice the speed measurable by using, instead of the distributor element 130, perforated panels arranged along its walls and having a plurality of through openings whose flow sections increase progressively from a minimum value to a maximum value going from the top towards the bottom of the same heat exchanger 110.
According to an embodiment of the invention, at the ends of the conduits 131a-131e facing towards the bottom of the heat exchanger 110 flow reducers may be advantageously applied, such as for example the reducers with lamellae typically used in air conditioning conduits, which offers the advantage of allowing variations and fine adjustments of the area of the through openings A1-A6. It is thus possible to optimize the air flow F through the heat exchanger 110, thus contributing positively to its heat exchange efficiency.
The possibility of minimizing pressure drops offers the further advantage of maintaining the noise of the air condenser 100 within the limits set by the relevant regulations.
According to one embodiment of the invention, on the walls of the conduits 131a-131e coatings made of a sound-absorbing material may be advantageously applied, for allowing a reduction of the overall noise of the air condenser 100.
The present invention has been disclosed with reference to its preferred embodiments. It will be understood that there can be further embodiments based on the same idea of solution and included within the scope of protection defined by the following claims.
Claims
1. A vertical discharge air condenser, said condenser comprising: wherein it further comprises a distributor element housed inside the heat exchanger coaxially thereto, said distributor element comprising a plurality of conduits arranged coaxially to each other, said conduits having a progressively increasing height from the top to the bottom of the heat exchanger and a progressively decreasing cross-section, the configuration of the distributor element being such that a plurality of through openings (A1-A6) are defined in the vertical direction (Z) from the top to the bottom of the heat exchanger, cross-sections of said through openings having the same nominal surface area.
- a heat exchanger having a cylindrical or polygonal shape that stretches out in a vertical direction (Z),
- an air suction device provided with a motorized fan housed in a frame arranged on the top of said heat exchanger,
2. The air condenser according to claim 1, wherein a first conduit of the distributor element having the largest transverse size and the lower height is arranged close to the top of the heat exchanger underneath the frame of the air suction device, while the other conduits of the distributor element are progressively spaced from the first conduit and one from the other in the vertical direction (Z).
3. The air condenser according to claim 2, wherein the arrangement of the conduits is such that, starting from the frame of the air suction device, an imaginary line(s) touching the top edges of the conduits is inclined towards the bottom of the heat exchanger by an angle comprised between 30° and 60°.
4. The air condenser according to claim 1, wherein flow adjusting devices are arranged at the ends of the conduits facing the bottom of the heat exchanger.
5. The air condenser according to claim 4, wherein said flow adjusting devices are of the type comprising a plurality of flaps.
6. The air condenser according to claim 1, wherein coatings made of a sound absorbing material are applied to the walls of the conduits.
7. The air condenser according to claim 1, wherein the distributor element is spaced from the bottom of the heat exchanger in the vertical direction (Z).
8. The air condenser according to claim 1, wherein the heat exchanger comprises a plurality of walls wherein each wall is made up of a shaped panel comprising a pair of inlet/outlet conduits for a cooling fluid extending in the vertical direction (Z), as well as of a plurality of micro-conduits that stretch out transversally between said conduits and are spaced by fins in the vertical direction (Z), said panel being bent or curved so as to form a portion of the periphery of the heat exchanger.
Type: Application
Filed: Jul 27, 2018
Publication Date: Jul 2, 2020
Applicant: Eurochiller S.r.l. (Castello d'Agogna (PV))
Inventors: Marco PARODI (Tagliolo Monferrato (AL)), Cesare BARBE (Vigevano (PV)), Alberto COSTA PISANI (Tagliolo Monferrato (AL))
Application Number: 16/632,994
