Patent Application
20250003651
This Patent Application claims priority from Italian Patent Application No. 102021000029945 filed on Nov. 26, 2021 the entire disclosure of which is incorporated herein by reference.
The present invention concerns an evaporator assembly, in particular a hybrid evaporator assembly.
The present invention finds its preferred, although not exclusive, application in a fluid conditioning circuit such as a conditioning circuit for refrigerating arrangements.
Evaporators are used for allowing the passage of a fluid from a liquid phase to a gaseous phases. In conditioning circuits evaporators are used for allowing a refrigerant fluid to pass from liquid phase to gaseous phases by subtracting heat from another operative fluid passing in the evaporator.
In particular, in almost all arrangement, the evaporator comprises a housing defining a space into which the refrigerant fluid is inserted and forced to pass through a tube bundle that is configured to allow the passage of operative fluid in the aforementioned space for exchanging heat with the refrigerant fluid.
Furthermore, the aforementioned evaporator arrangement may be designed in some known configuration, among which:
Another known typology of evaporators is the so-called hybrid evaporator i.e. a combination of flooded evaporators and falling film/spraying evaporators.
Hybrid evaporators are advantageous to increase performances of the evaporator assembly, in general.
However, hybrid evaporators still have a considerable load, i.e. they use a flow of refrigerant fluid that may be further optimized. Moreover, the distribution of the refrigerant fluid highly dependents on the typology of refrigerant fluid.
Accordingly, specific solutions for allowing a uniform distribution of the refrigerant fluid should be proposed, thereby increasing production costs. Conversely, a universal design solution would lead to a not-uniform distribution of the refrigerant fluid.
The not-uniform distribution of refrigerant fluid lead to a decreasing thermal exchange efficiency and increases the possibility that liquid phase evaporator fluid drops may be sucked downstream to the evaporator.
The need of a uniform distribution of refrigerant fluid is furthermore felt because both the outlet sucking conduit of the evaporator and the inlet refrigerant conduit are usually placed inclined with respect to a vertical axis of the evaporator and inclined one with respect to the other.
Such arrangement, needed because of installation requirements space, needs a good refrigerant fluid distribution to avoid drops of liquid phase refrigerant to be sucked by the outlet conduit.
Therefore, the need is felt to improve existing hybrid evaporator assemblies in order to increase their efficiency, in particular by reducing their load ad increasing the distribution of refrigerant fluid within the tube bundle.
An aim of the present invention is to satisfy the above mentioned needs in a cost-effective and optimized manner.
The aforementioned aim is reached by a hybrid evaporator assembly as claimed in the appended set of claims.
For a better understanding of the present invention, a preferred embodiment is described in the following, by way of a non-limiting example, with reference to the attached drawings wherein:
In the attached figures, reference number 1 globally indicates an evaporator assembly 1 according to the invention.
The evaporator assembly 1 comprises a housing 2 defining a closed space 3. The housing 2 comprises an intermediate portion 2a and a pair of terminal portion 2b configured to be secured to the intermediate portion 2a.
Preferably, the intermediate portion 2a has a tubular cylindrical shape extending along a longitudinal axis A; terminal portions 2b each comprises a perimeter part 2b′ configured to allow the fixation of the assembly 1 to ground or to support structure of a refrigerant apparatus and a central part 2b″ configured to mate with the intermediate portion 2a to close the space 3. In the disclosed embodiment, the perimeter pat 2b′ has a quadrangular shape.
Accordingly, space 3 has a cylindrical shape along axis A that is radially delimited by intermediate portion 2a and axially delimited by central part 2b″.
The evaporator assembly 1 further defines a first opening 4 and a second opening 5 configured to be coupled to, respectively, an outlet conduit (not shown) and an inlet conduit (not shown) of a refrigeration assembly comprising evaporator assembly 1.
According to the shown embodiment, the first and second openings 4, 5 are defined on respective first and second manifolds 6, 7, i.e. respectively an outlet and an inlet manifolds 6, 7, extending from an outer surface of the intermediate portion 2a of the housing 2.
In particular, the first and second manifolds 6, 7 extends along respective axis B and C that are inclined with respect to a vertical axis D perpendicular to longitudinal axis A of the evaporator assembly 1.
In particular, the axis C of second manifold 7 is preferably perpendicular to vertical axis D and to longitudinal axis A while the axis B of first manifold 6 is inclined, i.e. presenting an acute or obtuse angle with respect to axis C or D.
The housing 2 may further define other elements or openings, such as a level viewer 8 not further described into detail.
In the exemplarily shown embodiment two evaporator assemblies 1 are arranged with a common terminal portion 2b along longitudinal axis A.
The evaporator 1 assembly comprises a hybrid evaporation module 10 housed within the space 3, the hybrid evaporation module 10 comprises a refrigerant distributor 11, a tube bundle 12 and a support structure 13 for supporting the tube bundle 12 and, preferably, also the refrigerant distributor 11.
The tube bundle 12 comprises a plurality of tubes 12a, having preferably the same equivalent diameter; in the disclosed embodiment they are circular and all of the same diameter.
The tubes 12a are configured to allow the circulation of an operative fluid between an inlet 14 and an outlet 15, preferably carried by one of terminal portion 2b.
In particular the outer tubes 12a of the tubes bundle 12, e.g. second, third and fourth tubes groups 12″, 12′″, 12″″, are fluidly connected to inlet 14 while the inner tubes 12a of the tube bundle 12, e.g. first tubes group 12′ are fluidly connected to outlet 15. According to the above, the outer tubes 12a have a greater temperature with respect to the inner tubes 12a according to vertical axis D direction.
The inner and outer tubes 12a are fluidly connected together to allow the counter flow passage of the fluid contained therein in terminal portion 2b opposite to the one housing inlet 14 and outlet 15.
Conversely, in the terminal portion 2b housing the inlet 14 and outlet 15 divisor walls may be placed to guide the fluid flow in the correct outer and inner tubes without mixing. An exemplarily embodiment, not further described for sake of brevity, may be found in EP3748270 A1 for sake of example.
In particular, the tubes 12a are disposed symmetrically with respect to longitudinal axis A and are vertically placed below the distributor 11.
Advantageously, the support structure 13 comprises a plurality of walls configured to define a space 16 that is vertically delimited on one side and opened towards the bottom of space 3 on the opposite and laterally delimited by the wall of support structure 13. The space 16 has therefore a parallelepiped shape, opened towards the bottom.
The tubes 12a of tube bundle 12 are grouped in different tube groups. A first tubes group 12′ is housed in an upper portion of space 16, i.e. closer to distributor 11, a second tubes group 12″ is housed below the first tubes group 12′ and partially extends over space 16 in space 3, a third tubes group 12′″ extends in the bottom portion of space 3 and a pair of fourth tubes groups 12″″ are placed laterally comprised between the support structure 13 and intermediate portion 2a of housing 2 in an upper portion of space 3, i.e. above the half line of the cross-section of the intermediate portion.
In particularly, as more clear in
Making reference to
The distributor 11 is configured to be at least partially housed within space 13 and configured to let refrigerant fluid to be dispensed over tube bundle 12.
In particular, the distributor 11 comprises a plurality of distribution tubes 21 fluidly connected to a conduit assembly 22. The conduit 21 is fluidly connected to manifold 7 to allow refrigerant fluid flows within evaporator assembly 1 and is advantageously positioned in correspondence of intermediate portion 2a along longitudinal axis A.
In particular, it is noticed that distribution tubes 21 are placed within space 16 and conduit assembly 22 is placed partially through top wall of perimeter walls 20.
The distribution tubes 21 are placed vertically above the tube bundle 12 and are preferably placed in a row along transversal direction with respect to longitudinal axis A, i.e. they are placed at the same height. More preferably, they are displaced at the same transversal distance one with resect to the other, i.e. they are spaced transversally of the same distance.
The support structure 13 further comprises transversal walls 23 provided with a plurality of openings 24, such openings 24 are designed to house tubes 12a of the tube bundle 12 in order to provide to this latter support/guide along space 3.
According to the above described topology of the tubes 12a of tube bundle 12, the support structure 13 comprises a plurality of first transversal walls 23′ to support/guide first tubes group 12′, a plurality of second transversal walls 23″ to support/guide second tubes group 12″, a plurality of third transversal walls 23′″ to support/guide first tubes group 12′″ and a plurality of fourth transversal walls 23″″ to support/guide first tubes group 12″″.
The support structure 13 further comprises at least a longitudinal wall 24 extending parallel to longitudinal axis A in order to transversally subdivide space 16. In the described example, the support structure 13 comprises a pair of longitudinal walls 24 that divides space 16 into a pair of lateral portions that have the same transversal extension and a central portion that has a greater transversal extension with respect to lateral portions.
Preferably, longitudinal walls 24, and in case, lateral portion of perimeter wall 20, are provided with cantilevered walls 25 extending transversally from the longitudinal wall 24 inclined towards bottom portion of space 3 with respect to vertical axis D.
In the disclosed embodiment each longitudinal wall 24 and the lateral portion of perimeter wall 20 comprises a pair of cantilevered walls 25 that are vertically equally spaced one with respect to the other, i.e. they are placed in two rows. In particular, both sides of a longitudinal wall 24 is provided with cantilevered walls 25.
Preferably, longitudinal walls 24 are provided with openings 26 to allow fluidic communication between the above described portions of space 16.
The hybrid evaporation module further comprises a demister mesh 27 that is preferably carried by the support structure 13.
In particular, the demister mesh 27 is vertically placed between the bottom of the space 3 and the fourth tubes group 12″″ and carried by perimeter wall outside space 16, i.e. radially comprised between the perimeter wall 20 and intermediate portion 2a of housing 2.
The demister mesh 27 defines a plurality of openings 28 disposed into a web and configured to avoid the passage of drops from the bottom portion of space 3 and the first manifold 6.
Advantageously, the demister mesh 27 comprises sealing walls 29 extending vertically, i.e. along vertical axis D and configured to cooperate by contact with perimeter wall and the inner surface of the intermediate proton 2a in order to allow fluidic communication only through the demister mesh 27.
The aforementioned walls may be realized separately and fixed together or being realized, at least some among them, as one piece
The hybrid evaporation module 10 further comprises a distributor plenum 31 vertically interposed within the tube bundle 12 and configured to distribute refrigerant fluid along said vertical axis D direction.
In particular, the distributor plenum 31 is housed within space 16 and vertically comprises between the first and second tubes groups 12′, 12″ and laterally in contact with perimeter wall 20 so that refrigerant fluid is forced to pass through the distributor plenum 31.
Distributor plenum 31 comprises a plate element 32 extending along axis A and provided with a pair of lateral portion 32a with respect to longitudinal axis A and a central portion 32b laterally comprised by lateral portion 32a.
The central portion 32b is provided with a mesh of openings 33 distributed along all the area of the central portion 32b.
Advantageously, such openings 33 may have different diameters or may be distances with variable distances in function of the distance of the opening 33 with respect to outlet opening 4 in order to allow uniform distribution of the refrigerant fluid in counter action to the sucking pressure coming from outlet opening.
Accordingly, openings 33 that are nearer to the opening 4 may be smaller in diameter or have less density (i.e. they can be more distanced one with respect to the other) with respect to openings 33 that are more distant with respect to opening 4.
The lateral portions 32a have advantageously the same shape, i.e. they have a vertically variable profile configured to collect refrigerant fluid towards the central portion 32b. In particular, the variable profile is a linear profile that has the greatest height along vertical axis D in contact to perimeter wall 20 decreasing linearly till reaching the height of the central portion 32b.
The hybrid evaporation module 10 further comprises oil separation means 37 configured to improve oil separation with respect to the refrigerant fluid flow.
In particular, such oil separation means 37 comprises a pair of longitudinal walls 38 extending on at least part, preferably entirely, on the longitudinal axis direction within intermediate portion 2a of housing 2. Preferably, walls 38 are two and placed on opposite sides with respect to axis D, more preferably at the same distance thereof.
As exemplarily shown, the walls 38 are placed within the third tubes group 12′″ and extends from a lower portion of the intermediate portion 2a. In particular, the walls 38 each comprise a lower portion that extends radially with respect to the lower surface of intermediate portion 2a and an upper portion 38″ that extends from the lower portion 38′ in a direction parallel to vertical axis D.
It is furthermore noticed that the structure of the hybrid evaporation module 10 is symmetric with respect to vertical axis D and with respect to longitudinal axis A, i.e. the half of hybrid evaporation module 10 on the left with respect to vertical axis D is equal to the right half and the half of hybrid evaporation module 10 on the rear with respect to longitudinal axis A is equal to the front half.
The hybrid evaporation module 10 may further comprises ventilation plate 35 arranged within space 3 in proximity of first manifold 6 and configured to avoid direct sucking of the gaseous phase refrigerant flow from this latter, i.e. it forces the passage of refrigerant flow about the ventilation plate 35 before reaching the first manifold 6.
In greater detail, the ventilation plate 35 comprises a wall 36 that extends parallel to axis C direction from support structure 13 within space 3. In particular, the wall 36 extends perpendicularly from lateral walls of perimeter walls 30 above the fourth tubes group 12″″, i.e. just beneath the top portion of perimeter wall.
Preferably, the wall 36 has a variable length profile in the transversal direction of axis C, wherein the maximum transversal extension is in proximity of the first manifold 6 and the minimum extension is in the terminal longitudinal portions of the wall 36.
Making reference to
In particular, in the enlarged portion of
Preferably, such openings 40 are realized on a bottom portion of the conduits 21 and they are all along the same line, i.e. they run parallel on the bottom portion of the conduits 21 with respect to longitudinal axis A.
In particular, the openings 40 have preferably an oblong shape wherein the main opening direction of each opening 40 is parallel to longitudinal axis A.
Furthermore, the opening 40 may have a variable opening area in function of their distance with respect to conduit assembly 22, i.e. they can have a greater area as more each opening is distant with respect to conduit assembly 22. In this way, the refrigerant fluid may be distributed uniformly.
In particular, such openings are symmetrically distributed with respect to axis C of conduit assembly 22 so that the refrigerant fluid is uniformly distributed along axis A.
As better shown in
The distribution conduits 21 are furthermore connected together thanks to terminal transversal elements 41 and intermediate transversal elements 42, preferably both shaped as rectangular plates, extending parallel to axis C and defining plurality of openings configured to house the distribution conduits 21. In particular, the terminal transversal elements 41 defines blind openings configured to house the distribution conduits 21 and acting as a plug while the intermediate transversal elements 42 define trough openings configured to provide a support for the conduits 21 housed therein.
The external housing 22a further defines a pair of plurality of inner openings 43 configured to allow the fluidic communication of the external housing 22a with the distribution conduits 21. According to the disposition of the distribution conduits 21, the openings 43 are placed linearly parallel to axis C in two opposite rows with respect to axis C.
The conduit assembly 22 may further comprise an inner housing 22b that is dimensioned so as to be inserted within external housing 22a in tight manner. The inner housing 22b may be selectively fixed to external housing 22a, in particular to manifold 7, via fixation means such as threaded elements in at least an angular preset position with respect to axis C.
The inner housing 22b defines at least a first pair of plurality of openings 44 that are longitudinally spaced along axis C direction in order to match with inner openings 43 of external housing 22a. The inner housing 22b may define also further pairs of plurality of openings 44 opposed in diameter direction one with respect to the other.
The openings 44 of each pair of openings in inner housing 22b and/or the inner openings 43 of external housing 22a may have different diameter one with respect to the other along axis C direction in order to uniform the refrigerant fluid distribution to distribution conduits 21.
The conduit assembly 22 may further comprise a distribution plate 22e carried by a flanged portion 22d configured to be connected to a coupling portion 22c of the manifold 7 and configured to be fluidly interposed on the opening 5. The distribution plate 22e defines a plurality of openings (not shown) configured to uniform the distribution of refrigerant fluid within the inner housing 22b. The openings can be optimized in function of the typology of refrigerant fluid used in the conditioning circuit.
The operation of the above described hybrid assembly 1 is the following.
Making reference to
In greater detail, distribution conduits 22 flow the refrigerant fluid above the tube bundle 12. The refrigerant fluid is uniformly distributed on the upper tubes 12a and flows down tube by tube. During the passage through the tube bundle 12, it exchange heat through the external surface of tubes 12a with the operative fluid flowing therein, cooling this latter. The refrigerant fluid then collects in lower portion of space 3 flooding the lowest tubes 12a and continuing to exchange heat which this latter.
During the passage in the tube bundle 12, the cantilevered portions 25 help to avoid that refrigerant fluid tends to flow on longitudinal walls 24 or in perimeter walls 20. The same longitudinal walls 24 avoid that too much refrigerant fluid passes between central portion of space 16 and lateral portions of space 16.
The distribution plenum 31 further optimizes the refrigerant flow distribution, in particular avoiding an excessive flow passage in proximity of first manifold 6.
When evaporating, the gaseous phase refrigerant passes through the demister mesh 27, thereby reducing the possibility that liquid phase refrigerant may flow towards first manifold 6.
Following to the above passage, the gaseous phase refrigerant passes through the forth tubes group 12″″ thereby overheating and further avoiding that liquid phase refrigerant may flow towards the first manifold 6.
According to the above, it is clear that refrigerant fluid is evaporated and overheated thanks to the hybrid evaporation module 10.
In greater particular, during assembly of the evaporator assembly 1, the conduit 22 may be optimized for the peculiar typology of refrigerant fluid.
Indeed, the inner housing 22b and the distribution plate 22e can be substituted according to the specific refrigerant fluid so that their openings are optimized for such fluid. In case the inner housing 22b is provided with a plurality of pair of openings, only distribution plate 22e may be substituted and the inner housing 22b can be rotated to associate the correct openings 44 in communication with openings 43. In such case, angular references can be provided on the manifold 7 or on inner housing 22b.
In view of the foregoing, the advantages of an evaporator assembly 1 according to the invention are apparent.
The presence of the falling flow of refrigerant on tube bundle, optimized thanks to the different elements of the hybrid evaporation module 10 allows to reduce the refrigerant load, thereby increasing the efficiency of the evaporator assembly.
The presence of the demister mesh combined with the perimeter walls clearly divides the liquid-phase portion of space 3 with respect to the gaseous phase portion of space 3, thereby avoiding passage of fluid to first manifold 6.
The presence of the flooded portion in the bottom portion of space 3 allows to evaporate all refrigerant fluid and to provide a reservoir 4 refrigerant fluid for operational necessities.
The symmetric layout of hybrid evaporation module 10 improves the space optimization of the hybrid evaporation module 10 allowing a reduction of space an weight. Moreover, the symmetric layout improves the fluid distribution and the evaporated fluid suction.
The fact that the first and second manifolds 6, 7 are realized laterally with respect to vertical axis of the evaporator assembly 1 facilitates the installation with other elements of the refrigeration assembly.
The presence of the mesh demister interposed between the inner surface of the housing 2 and the perimeter wall 20, allows to delimit the above mentioned liquid-gaseous phase portion of space 3, avoiding liquid passage towards first manifold 6.
The presence of fourth tubes group 12″″ allows to overheat evaporated gas before suction by outlet conduit, further reducing the possibility of suction of liquid refrigerant.
The ventilation plate 35 further avoid the liquid suction by making uniform the suction flow coming from outlet conduit, thereby improving evaporator gaseous flows towards this latter.
The presence of plenum 31 allows to uniform the distribution of refrigerant liquid flow coming from a portion of the tube bundle, in particular avoiding a preference of direction in proximity to outlet conduit.
In particular, the fact that plenum 31 is placed inside the space 16 delimited by structure 13 forces the liquid to fall within the flooded portion so that cannot pass directly to outlet conduit.
The conduit assembly 22 comprising a fixed portion provided with distribution tubes 21 and a variable portion that can be inserted within the fixed portion allows to optimized the fluid distribution according to peculiar load of the machine or to a peculiar refrigerant fluid.
In particular, it is sufficient to substitute/rotate the inner housing 22b and to change the distribution plate 22e to vary the title of refrigerant fluid that is distributed to the distribution conduit.
Similarly, the variable area openings in conduits 43, 44 and 40 allows to uniformly distribute the refrigerant fluid along axis A and C of the refrigerant fluid.
According to the above, by simply changing the variable portion of the conduit assembly 22 it is possible to optimize the refrigerant assembly 1 to a different operation standard and/or to a different refrigerant fluid. Accordingly, design costs and versatility of the refrigerant is increased.
It is clear that modifications can be made to the described evaporator assembly 1 which do not extend beyond the scope of protection defined by the claims.
For example, the tube bundle 12 may have a different topology of tubes 12a that may have different shapes. Similar consideration may apply to distribution conduits 21.
Similarly, support structure 13 may have a different shape and/or its elements may be realized with different geometries or realized in many or single pieces connected among them.
The described openings in some elements may have different geometry or distribution with respect to the shown one.
In general, housing 2 may have a different shape and more evaporator assembly 1 can be linearly coupled as show in the attached drawings.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102021000029945 | Nov 2021 | IT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2022/061341 | 11/23/2022 | WO |
