BACKGROUND OF THE INVENTION
[0001] This application relates to multi-pass parallel flow heat exchangers in refrigerant
systems, wherein liquid and vapor refrigerant phases are undesirably separated in
one or more intermediate manifolds, resulting in refrigerant maldistribution amongst
downstream heat transfer tubes and consequent heat exchanger performance degradation.
In particular, this application relates to re-routing one of the refrigerant phases
(the liquid phase for the condensers and the vapor phase for the evaporators) from
at least one intermediate manifold to one or more downstream locations, bypassing
one or more banks of heat transfer tubes within the parallel flow heat exchanger and
subsequently allowing for uniform distribution of remaining predominantly single refrigerant
phase (the vapor phase for the condensers and the liquid phase for the evaporators)
among parallel heat transfer tubes that are positioned downstream and are in fluid
communication with this at least one intermediate manifold. Heat exchanger and overall
refrigerant system performance is thus enhanced.
[0002] Refrigerant systems utilize a refrigerant to condition a secondary fluid, such as
air, delivered to a climate-controlled space. In a basic refrigerant system, the refrigerant
is compressed in a compressor, and flows downstream to a condenser, where heat is
typically rejected from the refrigerant to an ambient environment, during heat transfer
interaction with this ambient environment. Then refrigerant flows through an expansion
device, where it is expanded to a lower pressure and temperature, and to an evaporator,
where during heat transfer interaction with another secondary fluid (e.g., indoor
air), the refrigerant is evaporated and typically superheated, while cooling and often
dehumidifying this secondary fluid.
[0003] In recent years, much interest and design effort has been focused on the efficient
operation of the heat exchangers (condensers and evaporators) in the refrigerant systems.
One relatively recent advancement in the heat exchanger technology is the development
and application of parallel flow, or so-called microchannel or minichannel, heat exchangers
(these two terms will be used interchangeably throughout the text), as the condensers
and evaporators.
[0004] These heat exchangers are provided with a plurality of parallel heat transfer tubes,
typically of a non-round shape, among which refrigerant is distributed and flown in
a parallel manner. The heat transfer tubes are orientated generally substantially
perpendicular to a refrigerant flow direction in inlet, intermediate and outlet manifolds
that are in flow communication with the heat transfer tubes. The primary reasons for
the employment of the parallel flow heat exchangers, which usually have aluminum furnace-brazed
construction, are related to their superior performance, high degree of compactness,
structural rigidity and enhanced resistance to corrosion.
[0005] When utilized in many condenser and evaporator applications, these heat exchangers
are normally designed for a multi-pass configuration, typically with a plurality of
parallel heat transfer tubes within each refrigerant pass, in order to obtain superior
performance by balancing and optimizing heat transfer and pressure drop characteristics.
In such designs, the refrigerant that enters an inlet manifold (or so-called inlet
header) travels through a first multi-tube pass across a width of the heat exchanger
to an opposed, typically intermediate, manifold. The refrigerant collected in a first
intermediate manifold reverses its direction, is distributed among the heat transfer
tubes in the second pass and flows to a second intermediate manifold. This flow pattern
can be repeated for a number of times, to achieve optimum heat exchanger performance,
until the refrigerant reaches an outlet manifold (or so-called outlet header). Typically,
the individual manifolds are of a cylindrical shape (although other shapes are also
known in the art) and are represented by different chambers separated by partitions
within the same manifold construction assembly.
[0006] Heat transfer corrugated and typically louvered fins are placed between the heat
transfer tubes for outside heat transfer enhancement and construction rigidity. These
fins are usually attached to the heat transfer tubes during a furnace braze operation.
Furthermore, each heat transfer tube preferably contains a plurality of relatively
small parallel channels for in-tube heat transfer augmentation and structural rigidity.
[0007] However, there have been some obstacles to the use of the parallel flow heat exchangers
in a refrigerant system. In particular, a problem, known as refrigerant maldistribution,
typically occurs in the microchannel heat exchanger manifolds when the two-phase flow
enters the manifold. A vapor phase of the two-phase flow has significantly different
properties, moves at different velocities and is subjected to different effects of
internal and external forces than a liquid phase. This causes the vapor phase to separate
from the liquid phase and flow independently. The separation of the vapor phase from
the liquid phase has raised challenges, such as refrigerant maldistribution in parallel
flow heat exchangers. This phenomenon takes place due to unequal pressure drop inside
the channels and in the inlet and outlet manifolds, as well as poor manifold and distribution
system design. In the manifolds, the difference in length of refrigerant paths, phase
separation and gravity are the primary factors responsible for maldistribution. Inside
the heat exchanger channels, variations in the heat transfer rate, airflow distribution,
manufacturing tolerances, and gravity are the dominant factors. Furthermore, a recent
trend of heat exchanger performance enhancement promoted miniaturization of its channels,
which in turn negatively impacted refrigerant distribution. Since it is extremely
difficult to control all these factors, along with the complexity and inefficiency
of the proposed techniques or prohibitively high cost of the solutions, many of the
previous attempts to manage refrigerant distribution, have failed.
[0008] On the other hand, refrigerant maldistribution may cause significant heat exchanger
and overall system performance degradation over a wide range of operating conditions.
Therefore, it would be desirable to reduce or eliminate refrigerant maldistribution
in parallel flow heat exchangers.
[0009] EP 0886113 A2 discloses a system as set out in the precharacterising portion of claim 1.
SUMMARY OF THE INVENTION
[0010] The invention provides a refrigerant system as defined in claim 1 and a method of
operating a refrigerant system as defined in claim 14.
[0011] In disclosed embodiments of this invention, one of the phases of a two-phase refrigerant
mixture, which is the liquid phase for condensers and the vapor phase for evaporators,
is tapped from a location within a parallel flow heat exchanger, where a liquid phase
is likely to separate from a vapor phase and accumulate, causing refrigerant maldistribution
in downstream heat transfer tubes that are in fluid communication with this upstream
location. Tapped, predominantly single-phase refrigerant, which is, once again, liquid
for the condensers and vapor for the evaporators, is redirected into a downstream
location in a parallel flow heat exchanger, where refrigerant is already in a predominantly
single phase (the liquid phase for condensers and the vapor phase for evaporators).
by passing at least some of the downstream heat transfer tube banks (or passes). Therefore,
the remaining predominantly single phase refrigerant (vapor for the condensers and
liquid for the evaporators) flowing through the next pass of the parallel flow heat
exchanger can be uniformly distributed among parallel heat transfer tubes that are
positioned downstream of the redirection (or tap) location and are in fluid communication
with this location. As a result, both heat exchanger and overall refrigerant system
performance are improved.
[0012] In one embodiment, a predominantly single-phase refrigerant is tapped from an intermediate
manifold and redirected to another downstream intermediate manifold. In another embodiment,
a predominantly single-phase refrigerant is tapped from an intermediate manifold and
redirected to an outlet manifold. Although manifold locations are preferred and the
most convenient tapping and bypass return points, other positions in the parallel
flow heat exchangers are also feasible and within the scope of the invention. Moreover,
if for instance, the manifold locations are utilized as the tapping points, a predominantly
liquid bypass refrigerant flow in the condenser applications is taken from a location
close to the bottom of the manifold of manifold chamber and a predominantly vapor
bypass refrigerant flow for the evaporator applications is taken from a location close
to the top of the manifold or manifold chamber.
[0013] Furthermore, in some embodiments, a single-phase refrigerant is tapped from a single
location within a parallel flow heat exchanger, and in other embodiments, multiple
tapping points are used. Also, although a single bypass return point is the most feasible,
multiple bypass return points may be driven by design and space limitations and are
within the scope of the invention.
[0014] The bypass line can be placed in the path of the secondary media, such as air, to
obtain additional heat transfer and further improve the heat exchanger and overall
system performance. Also, the bypass line may have internal and external heat transfer
enhancement elements to further improve heat transfer between a predominantly single-phase
bypass refrigerant and a secondary fluid. Since a counterflow arrangement is desired,
the bypass line is preferably placed upstream of the parallel flow heat exchanger
for both condenser and evaporator applications, with respect to the secondary fluid
flow.
[0015] The invention is applicable for any multi-pass parallel flow heat exchanger shape
and configuration, with any number of passes, and with a general upward or downward
refrigerant flow direction. Further, the invention is beneficial for any parallel
flow heat exchanger orientation, including horizontal, vertical and inclined.
[0016] In various embodiments, the tapped refrigerant bypass is arranged by various methods.
In some embodiments, there is a hole in a separation plate between the manifold chambers
that may be controlled by a float device (for the liquid phase bypass), check valve
or solenoid valve. Of course, other methods of control known in the art are also applicable
and within the scope of the invention. In other embodiments, an actual bypass return
line is utilized to return refrigerant to a downstream location and a valve may be
placed on this bypass return line to control the flow of a predominantly single-phase
bypass refrigerant.
[0017] As stated above, the disclosed invention can be implemented in parallel flow heat
exchanger installations functioning as condensers as well as evaporators.
[0018] These and other features of the present invention can be best understood from the
following specification and drawings, the following of which is a brief description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019]
Figure 1 shows a refrigerant system incorporating the present invention.
Figure 2A shows a first schematic.
Figure 2B shows a heat transfer tube design feature.
Figure 3 shows a second schematic.
Figure 4 shows a third schematic.
Figure 5 shows a fourth schematic.
Figure 6 shows a fifth schematic.
Figure 7 shows a sixth schematic.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] A basic refrigerant system 20 is illustrated in Figure 1 and includes a compressor
22 delivering refrigerant into a discharge line 23 heading to a condenser 24. The
condenser 24 is a parallel flow heat exchanger, and in one disclosed embodiment is
a microchannel heat exchanger. The heat is transferred in the condenser 24 from the
refrigerant to a secondary fluid, such as ambient air. The high pressure, but desuperheated,
condensed and typically subcooled, refrigerant passes into a liquid line 25 downstream
of the condenser 24 and through an expansion device 26, where it is expanded to a
lower pressure and temperature. Downstream of the expansion device 26, refrigerant
flows through an evaporator 28 and back to the compressor 22. An evaporator 28 may
also be a parallel flow heat exchanger. In the evaporator 28, the heat is transferred
from another secondary fluid, such as air delivered to the conditioned environment,
to the refrigerant that is evaporated and typically superheated during heat transfer
interaction with this secondary fluid. Although a basic refrigerant system 20 is shown
in Figure 1, it is well understood by a person of ordinarily skill in the art that
many options and features may be incorporated into a refrigerant system design. All
these refrigerant system configurations are well within the scope and can equally
benefit from the invention. Also, although all the embodiments are described in the
relation to the condenser applications, it is well understood by a person skilled
in the art that a similar approach can be utilized for evaporators, where a predominantly
vapor phase (instead of a liquid phase in the condenser applications) is bypassed,
allowing remaining liquid phase (instead of the vapor phase in the condenser applications)
to be uniformly distributed among the downstream heat transfer tubes.
[0021] As shown in Figure 2A, the multi-pass condenser 24 has a manifold structure 30 that
consists of multiple chambers 30A, 30B and 30C. An inlet manifold chamber 30A receives
the refrigerant, typically in a vapor phase, from the discharge line 23. The refrigerant
flows into a first bank of parallel heat transfer tubes 32, and then across the condenser
core to a chamber 34A of an intermediate manifold structure 34. It should be noted
that, in practice, there may be more or less refrigerant passes than the four illustrated
passes 32, 36, 38, and 40. Further, it should be understood that, although for simplicity
purposes each refrigerant pass is represented by a single heat transfer tube, typically
there are many heat transfer tubes within each pass amongst which refrigerant is distributed
while flowing within the pass, and, in the condenser applications, a number of the
heat transfer tubes within each bank (or pass) typically decreases in a downstream
direction with respect to a refrigerant flow. For instance, there could be 12 heat
transfer tubes in the first bank, 8 heat transfer tubes in a second bank, 5 heat transfer
tubes in a third bank and only 2 heat transfer tubes in the fourth bank. A separator
plate 42 is placed within the manifold 34 to separate the chamber 34A from a chamber
34B positioned within the same manifold structure 34.
[0022] As shown in the Figure 2A, at chamber 34A, the refrigerant is starting to condense
while flowing through the first pass along the tubes 32 (due to heat transfer interaction
with a secondary fluid) and is in a two-phase thermodynamic state, although typically
with a relatively small liquid amount in a two-phase mixture. Also, at this location,
liquid phase may be starting to separate from the vapor refrigerant, as shown by 35,
since liquid and vapor phases have different thermophysical properties and are affected
differently by external forces such as gravity and momentum sheer. Separation of liquid
and vapor phases may create maldistribution conditions, while the refrigerant flows
from the chamber 34A of the intermediate manifold structure 34 back across the core
of the condenser 24 through a second bank of parallel heat transfer tubes 36 into
a chamber 30B of the manifold structure 30.
[0023] Since, in some cases, a somewhat insignificant amount of liquid refrigerant is accumulated
within the chamber 34A, refrigerant maldistribution may not have a profound effect
on the performance of the condenser 24 yet. Still, a float valve 52 and drain orifice
50 are shown to discharge liquid refrigerant into the adjacent chamber 34B, bypassing
the downstream second and third banks of heat transfer tubes 36 and 38 respectively.
As a result, favorable conditions are created for uniform distribution of a predominantly
single-phase vapor refrigerant among the second bank of heat transfer tubes 36. The
refrigerant entering the second bank of heat transfer tubes 36 is predominantly in
a vapor phase and is flowing in generally parallel (although counterflow) direction
to the refrigerant flow in the first bank of heat transfer tubes 32. As shown in the
Figure 2A, a separator plate 42 prevents refrigerant mixing or direct flow communication
between the manifold chambers 30A and 30B. In the chamber 30B, the refrigerant is
also in a two-phase thermodynamic state but containing lower vapor quality and potentially
promoting the conditions for liquid refrigerant accumulation, as shown at 144, at
the bottom of the chamber 30B.
[0024] In such circumstances, vapor refrigerant will predominantly flow into the upper portion
of the heat transfer tubes of the third pass 38 with liquid refrigerant flowing through
the lower portion of the third bank 38 of heat transfer tubes. Therefore, refrigerant
maldistribution may have a profound effect on performance of the condenser 24. Another
float valve 52 and drain orifice 50 assembly discharges that liquid refrigerant downstream
into the adjacent chamber 30C, bypassing the third and forth banks of heat transfer
tubes 38 and 40 respectively. Consequently, the uniform distribution of a predominantly
single-phase vapor refrigerant among the third bank of heat transfer tubes 38 can
be achieved.
[0025] The predominantly single phase vapor refrigerant flows, for further condensation,
from the intermediate chamber 30B of the manifold structure 30 into a third bank of
parallel heat transfer tubes 38 generally positioned in parallel arrangement to the
first and second banks of heat transfer tubes 32 and 36, across the condenser 24 and
into an intermediate chamber 34B of the manifold structure 34. The liquid refrigerant
level in the manifold chamber 34B, as shown at 244, may be even higher than levels
35 and 144, since liquid refrigerant from the intermediate manifold chamber 34A directly
enters intermediate manifold chamber 34B through the orifice 50. It should be understood
that the liquid levels 35, 144 and 244 may be somewhat exaggerated to illustrate the
concept of the present invention as well as may vary with operating and environmental
conditions.
[0026] The refrigerant flowing through the chamber 34B has even lower vapor quality and
potentially creating similar maldistribution conditions for the fourth (and last)
bank of heat transfer tubes 40. Again, the orifice 50 in the separator plate 42 positioned
between the chambers 30B and 30C allows the flow of liquid refrigerant to enter from
the intermediate manifold chamber 30B into the intermediate manifold chamber 30C and
mix with the refrigerant flow leaving the forth bank of heat transfer tubes 40, while
the float valve 52 prevents vapor refrigerant flow between the same chambers.
[0027] From the chamber 30C, the liquid refrigerant exits condenser 24 through the line
25. As known, corrugated, and typically louvered, fins 33 are located between and
attached to the heat transfer tubes (typically during a furnace brazing process) to
extend the heat transfer surface and improve structural rigidity of the condenser
24.
[0028] As shown in Figure 2B, the heat transfer tubes within the tube banks 32, 36, 38,
and 40 may consist of a plurality of parallel channels 100 separated by walls 101.
The Figure 2B is cross-sectional view of the heat transfer tubes shown in Figure 2A.
The channels 100 allow for enhanced heat transfer characteristics and assist in improved
structural rigidity. The cross-section of the channels 100 may take different forms,
and although illustrated as a rectangular in Figure 2B, may be, for instance, of triangular,
trapezoidal or circular configurations.
[0029] In the present invention, liquid refrigerant is tapped from the liquid accumulation
locations within the two-phase flow portion of the condenser 24 (that may or may not
be directly associated with the separator plates 42 dividing the manifold chambers)
and directed to the locations downstream where a predominantly single-phase liquid
refrigerant is flowing, thus bypassing the region where a two-phase refrigerant is
present and avoiding maldistribution conditions for the downstream heat transfer tube
bank. Therefore, the parallel flow heat exchanger and overall refrigerant system performance
is improved. Alternatively, a heat exchanger of a smaller size can be allowed, if
no performance enhancement is required.
[0030] Although the float valve 52 is illustrated having a spherical shape, it also may
have other configurations such as conical, cylindrical, etc. Further, other type valves,
such as a solenoid valve or a check valve, can be employed instead. Although an internal
bypass between the manifold chambers is convenient, it may not always be feasible
(e.g., when the manifold chambers are positioned at the opposite ends of the heat
exchanger) or desired from a manufacturing complexity point of view. In such circumstances,
an external bypass may be established instead, such a bypass line 53 tapping liquid
refrigerant from a location 244 close to the bottom of the manifold chamber 34B to
a downstream location 54 within the outlet manifold chamber 30C. In the outlet manifold
chamber 30C, the three liquid refrigerant flows (leaving the forth bank of heat transfer
tubes 40, bypassed from the chamber 30B to the chamber 30C and bypassed from the chamber
34B to the chamber 30C) are mixed. A flow control device, such as valve 49, may be
positioned on the bypass line 53 and associated with a control 10 to allow the flow
of this liquid refrigerant to be pulsed, modulated or completely shutdown. In this
manner, a refrigerant system designer can achieve additional precise control over
the desired amount of the bypassed liquid refrigerant flow, which can be tailored,
for instance, to specific operating conditions, to provide even more uniform distribution
of liquid and vapor refrigerant phases amongst the heat transfer tubes. Analogously,
in case the float valves 52 are replaced by solenoid valves, a similar type of control
can be executed for these valves as well. Additionally, level measurement devices
installed with the liquid refrigerant flow control devices can be positioned in the
manifold chambers, if desired or required for proper operation of these liquid refrigerant
flow control devices. Lastly, other locations, rather than intermediate manifold chambers,
can be selected for tapping of liquid refrigerant.
[0031] The bypass line 53 may have internal and external heat transfer enhancement elements
and be placed into the path of the secondary media, such as ambient air, flowing across
the condenser 24. Further, in order to maintain overall counterflow configuration,
the bypass line 53 is preferably placed upstream of the heat transfer core of the
condenser 24, in relation to the airflow.
[0032] Figure 3 shows another embodiment 124 of the parallel flow condenser having three
passes and inlet and outlet tubes 23 and 153 respectively positioned on opposite sides
of the heat exchanger core, wherein a fixed orifice of a predetermined size 54 replaces
the float valve 52 and orifice 50 assembly of the first intermediate manifold chamber
34A shown in Figure 2A. The size of the orifice 54 is to be selected to maintain a
liquid seal between the intermediate manifold chambers 34A and 34B at all operating
conditions. Similarly to the Figure 2A embodiment, an orifice 50 and float valve 52
assembly is included to pass the liquid refrigerant from an intermediate manifold
chamber 30B into a bypass return line 56, and back to a location 51 and to an outlet
tube 153. In all other aspects the Figure 3 embodiment is similar to the Figure 2A
embodiment.
[0033] Figure 4 shows yet another embodiment 224 of a parallel flow condenser having two
passes, wherein a single bypass return line 53 redirects predominantly liquid refrigerant
from an intermediate manifold 34 to the downstream point 160 and into an outlet manifold
chamber 30B, to be combined with the refrigerant exiting a second bank of heat transfer
tubes 36. In all other aspects the Figure 4 embodiment is similar to the Figure 2A
embodiment.
[0034] Figure 5 shows another embodiment 324 of a parallel flow condenser having four passes,
wherein bypass return lines 58 and 62 redirect the predominantly liquid refrigerant
from an intermediate manifold chamber 30B into an outlet tube 25 and from an intermediate
manifold chamber 34B into an outlet manifold chamber 30C respectively, or to the locations
60 and 64 where a predominantly single-phase liquid refrigerant is already present.
Once again, in the absence of active flow control devices associated with the bypass
lines, maintenance of a liquid seal at all operating conditions is essential. In this
embodiment, the refrigerant flow is generally upward but in all other aspects it is
similar to the Figure 2A embodiment.
[0035] Figure 6 shows yet another embodiment 424 of the parallel flow condenser having three
refrigerant passes, inlet and outlet manifold chambers on opposite sides of the condenser
core and generally upward refrigerant direction, wherein a bypass return line 62 is
utilized to redirect liquid refrigerant from an intermediate manifold chamber 30B
to an outlet manifold chamber 34B. Once again, liquid seal maintenance at all operating
conditions is critical. Also, in both Figure 5 and 6 embodiments, where the refrigerant
flow is generally upward, the pressure drop through the bypassed bank of heat transfer
tubes (e.g., bank 40 in the Figure 5 embodiment and bank 38 in the Figure 6 embodiment)
should be less than the pressure drop through the bypass return line 58 plus hydrostatic
head between the chambers 30B and 30C in the Figure 5 embodiment and through the bypass
return line 62 plus hydrostatic head between the chambers 30B and 34B in the Figure
6 embodiment.
[0036] Figure 7 shows another embodiment 524 of a parallel flow condenser having two passes
where a bypass return line 70 leads to a point 68 in the outlet manifold chamber 30A
where it mixes with the refrigerant exiting the second bank of the heat transfer tubes
36, and includes a float valve 80 and orifice 66. In all other aspects, this embodiment
is similar to the Figure 5 and Figure 6 embodiments.
[0037] In summary, in the present invention, one of the phases of a two-phase refrigerant
mixture, which is liquid phase for the condensers and vapor phase for the evaporators,
is tapped from a location within a parallel flow heat exchanger where a liquid phase
is likely to separate from a vapor phase and accumulate, causing refrigerant maldistribution
in downstream heat transfer tubes that are in fluid communication with this upstream
location. Tapped, predominantly single-phase refrigerant (once again, liquid for the
condensers and vapor for the evaporators), is redirected into a downstream location
in a parallel flow heat exchanger, where refrigerant is already in a predominantly
single phase (the liquid phase for condensers and vapor phase for the evaporators),
bypassing at least some of the downstream heat transfer tube banks (or passes). Therefore,
the remaining predominantly single-phase refrigerant (vapor for the condensers and
liquid for the evaporators) flowing through the next pass of the parallel flow heat
exchanger can be uniformly distributed among parallel heat transfer tubes that are
positioned downstream of the redirection (or tap) location and are in fluid communication
with this location. As a result, both heat exchanger and overall refrigerant system
performance are improved.
[0038] A predominantly single-phase refrigerant is tapped from an intermediate manifold
and redirected to another downstream intermediate manifold, or to an outlet manifold,
or to outlet refrigerant line. Although manifold locations are preferred and the most
convenient tapping and bypass return points, other positions in the parallel flow
heat exchangers are also feasible and within the scope of the invention. The redirection
method can be internal to the heat exchanger design, such as redirection through the
plates separating the manifold chambers, or external, such as bypass refrigerant lines.
Active flow control devices, such as solenoid or float valves, or passive bypass devices,
such as orifices or check valves, can be used.
[0039] Furthermore, a single-phase refrigerant may be tapped from a single location within
a parallel flow heat exchanger or from multiple tapping points. Also, although a single
bypass return point is the most feasible, multiple bypass return points may be driven
by design and space limitations and are within the scope of the invention.
[0040] It has to be noted that the bypass line can be placed in the path of a secondary
media, such as air, to obtain additional heat transfer and further improve the heat
exchanger and overall system performance. The bypass line may have internal and external
heat transfer enhancement elements to further improve heat transfer between a predominantly
single-phase bypass refrigerant and a secondary fluid. Since a counterflow arrangement
is desired, the bypass line is preferably placed upstream of the parallel flow heat
exchanger core for both condenser and evaporator applications, with respect to the
secondary fluid flow.
[0041] The invention is applicable for any multi-pass parallel flow heat exchanger shape
and configuration with any number of passes and with a general upward or downward
refrigerant flow direction. In an upward condenser configuration, the pressure drop
through the bypass return line and hydrostatic head should not exceed the pressure
drop through the bypassed tube bank for the desired amount of the bypass refrigerant
flow. Also, in many cases, as stated above, a good liquid seal is important for proper
operation and functionality, in the absence of active flow control devices. Further,
the invention is beneficial for any parallel flow heat exchanger orientation, including
horizontal, vertical and inclined.
[0042] The tapped single-phase refrigerant may be actively controlled to maintain the liquid
seal for improved functionality or to adjust thermodynamic conditions of refrigerant
at the heat exchanger exit. Also, sensors, such as a liquid level sensor, can be employed
in conjunction with these flow control devices. While the main discussion in the invention
is focused on condenser applications, refrigerant system evaporators can also benefit
from the invention. In the evaporator applications, a predominantly single-phase vapor
refrigerant is bypassed around some of the heat transfer tube banks (instead of liquid
in condenser applications). Also, if for instance, the manifold locations are utilized
as the tapping points, a predominantly vapor bypass flow for the evaporator applications
is to be taken from the location close to the top of the manifold or manifold chamber
(a predominantly liquid bypass flow in condenser applications is to be taken from
the location close to the bottom of the manifold or manifold chamber). In most other
aspects, the invention concept is similar for condenser and evaporator applications.
[0043] While the invention is disclosed for parallel flow heat exchangers, it does have
applications for other heat exchanger types, for instance, for the heat exchangers
having intermediate manifolds in the condenser applications. Also, the number of passes
shown is purely exemplary, and a heat exchanger with any number of passes can equally
benefit from the present invention. Further, the manifold constructions 30 and 34
encompassing a number of chambers may have many different design shapes and configurations.
Also, the manifold chambers may not necessarily be positioned within the same manifold
construction.
[0044] Although a preferred embodiment of this invention has been disclosed, a worker of
ordinary skill in the art would recognize that certain modifications would come within
the scope of this invention. For that reason the following claims should be studied
to determine the true scope and content of this invention.
1. A refrigerant system (20) comprising:
a condenser (24; 124;224;324;424;524);
a compressor (22);
an expansion device (26); and
an evaporator (28),
the compressor for delivering a compressed refrigerant to the condenser, refrigerant
from said condenser passing through the expansion device, and from said expansion
device through the evaporator, and from said evaporator being returned to said compressor;
and
at least one of said condenser and said evaporator having a plurality of heat transfer
tubes (32,36,38,40) which pass a refrigerant downstream in a generally parallel manner;
and
at least one location (30B,34A,34B,34) within said evaporator (28) being likely to
receive separated vapor and liquid phases of refrigerant mixture as the refrigerant
flows through the plurality of heat transfer tubes, characterised by at least a portion of a separated vapor phase being tapped from said location and
delivered to a downstream location (30C,34B;30;25) bypassing at least some of the
heat transfer tubes to Improve distribution of a remaining refrigerant flowing through
the bypassed heat transfer tubes that are in direct fluid communication with this
location.
2. The refrigerant system (20) as set forth In Claim 1, comprising
at least one location (30B,34A,34B,34) within said condenser being likely to receive
separated vapor and liquid phases of refrigerant mixture as the refrigerant flows
through the plurality of heat transfer tubes, and at least a portion of a separated
liquid phase being tapped from said location and delivered to a downstream location
(30C,34B;30;25) bypassing at least some of the heat transfer tubes to improve distribution
of a remaining refrigerant flowing through the bypassed heat transfer tubes that are
in direct fluid communication with this location
3. The refrigerant system (20) as set forth in Claim 1 or 2, wherein said at least one
of said condenser (24;124;224;324;424;524) and said evaporator (28) has at least one
manifold structure (30,34) in fluid communication with said plurality of heat transfer
tubes (32,36,38,40), said at least one manifold structure being provided with at least
one separation member providing at least two chambers (30A,30B,30C,34A,34B) within
said at least one manifold structure, and at least one of said chambers being said
tap location.
4. The refrigerant system (20) as set forth in Claim 3, wherein said separation member
is one of a separation plate (42), a check valve, a float valve (52;80), a solenoid
valve, an orifice with a liquid seal and a combination thereof.
5. The refrigerant system (20) as set forth In Claim 1 or 2, wherein said at least one
of said condenser (24;124;224;324;424;524) and said evaporator (28) has at least one
manifold structure (30,34) in fluid communication with said plurality of heat transfer
tubes (32,36,38,40), said at least one manifold structure being provided with at least
one separation member providing at least two chambers (30A,30B,30C,34A,34B) within
said at least one manifold structure, and at least one of said chambers being said
downstream location (30C,34B;30;25).
6. The refrigerant system (20) as set forth in Claim 1 or 2, wherein said at least one
of said condenser (24;124;224;324;424;524) and said evaporator (28) has an outlet
refrigerant tube (25) and said outlet refrigerant tube being said downstream location
(30C;34B;30;25).
7. The refrigerant system (20)as set forth in any preceding Claim, wherein said separated
refrigerant Is at least partially carried by a bypass line (53;56;62;78).
8. The refrigerant system (20) as set forth in Claim 7, wherein said bypass line (53;56;62;78)
has at least one of external and internal heat transfer enhancement elements.
9. The refrigerant system (20) as set forth in Claim 7, wherein said bypass line (53;56;62;78)
associated with at least one of said condenser (24;124;224;324;424; 524) and said
evaporator (28) Is positioned in the airflow path moving over at least one of said
condenser and said evaporator.
10. The refrigerant system (20) as set forth in Claim 9, wherein said bypass line (53;56;62;78)
associated with at least one of said condenser (24;124;224;324;424; 524) and said
evaporator (28) is positioned upstream at least one of said condenser and said evaporator,
in relation to the airflow.
11. The refrigerant system (20) as set forth in any preceding Claim, wherein each of said
plurality of heat transfer tubes (32,36,38,40) have a plurality of small parallel
Internal channels (100) carrying refrigerant in parallel paths within said heat transfer
tubes, and wherein said parallel internal channels create a microchannel heat transfer
tube or a minichannel heat transfer tube.
12. The refrigerant system (20) as set forth in any preceding Claim, wherein there are
multiple tap locations.
13. The refrigerant system (20) as set forth in any preceding Claim, wherein there are
multiple downstream locations.
14. A method of operating a refrigerant system comprising the steps of:
(1) providing a compressor (22) for delivering a compressed refrigerant to a condenser
(24;124;224;324;424;524), refrigerant from said condenser passing through an expansion
device (26), and from said expansion device through an evaporator (28), and from said
evaporator being returned to said compressor; and
(2) providing at least one of said condenser and said evaporator having a plurality
of heat transfer tubes (32,36,38,40) which pass a refrigerant downstream in a generally
parallel manner;
characterised by the step of:
(3) identifying at least one location (34A,34B,30B;34) within said evaporator (28)
likely to receive separated vapor and liquid phases of refrigerant mixture as the
refrigerant flows through the plurality of heat transfer tubes, and at least a portion
of a separated vapor phase being tapped from said location and delivered to a downstream
location (30C,34B;30;25) bypassing at least some of the heat transfer tubes to improve
distribution of a remaining refrigerant flowing through the bypassed heat transfer
tubes that are In direct fluid communication with this location.
15. The method as set forth In claim 14, comprising the step of (4) identifying at least
one location (34A,34B,30B;34) within said condenser (24;124;224;324;424;524) likely
to receive separated vapor and liquid phases of refrigerant mixture as the refrigerant
flows through the plurality of heat transfer tubes, and at least a portion of a separated
liquid phase being tapped from said location and delivered to a downstream location
(30C,34B;30,25) bypassing at least some of the heat transfer tubes to improve distribution
of a remaining refrigerant flowing through the bypassed heat transfer tubes that are
In direct fluid communication with this location.
1. Kälteanlage (20), umfassend:
- einen Kondensator (24; 124; 224; 324; 424; 524);
- einen Kompressor (22);
- eine Expansionsvorrichtung (26); und
- einen Verdampfer (28),
wobei der Kompressor dazu gedacht ist, ein komprimiertes Kältemittel an den Kondensator
abzugeben, wobei das Kältemittel von dem Kondensator durch die Expansionsvorrichtung
und von der Expansionsvorrichtung durch den Verdampfer geht und von dem Verdampfer
zum Kompressor zurückgeführt wird; und
wobei mindestens einer von dem Kondensator und dem Verdampfer eine Vielzahl von Wärmeübertragungsröhren
(32, 36, 38, 40) aufweist, die ein Kältemittel stromabwärts allgemein parallel durchlassen;
und
wobei mindestens eine Stelle (30B, 34A, 34B, 34) innerhalb des Verdampfers (28) geeignet
ist, um getrennte Dampf- und Flüssigkeitsphasen des Kältemittelgemischs aufzunehmen,
während das Kältemittel durch die Vielzahl von Wärmeübertragungsröhren fließt,
dadurch gekennzeichnet, dass mindestens ein Teil einer getrennten Dampfphase an der Stelle abgezapft und an eine
stromabwärtige Stelle (30C, 34B; 30; 25) abgegeben wird, wobei er mindestens einige
der Wärmeübertragungsröhren umgeht, um die Verteilung eines verbleibenden Kältemittels,
das durch die umgangenen Wärmeübertragungsröhren fließt, die in direkter Fluidkommunikation
mit dieser Stelle stehen, zu verbessern.
2. Kälteanlage (20) nach Anspruch 1, umfassend:
mindestens eine Stelle (30B, 34A, 34B, 34) innerhalb des Kondensators, die geeignet
ist, um getrennte Dampf- und Flüssigkeitsphasen des Kältemittelgemischs aufzunehmen,
während das Kältemittel durch die Vielzahl von Wärmeübertragungsröhren fließt, und
wobei mindestens ein Teil einer getrennten Flüssigkeitsphase an der Stelle abgezapft
und an eine stromabwärtige Stelle (30C, 34B; 30; 25) abgegeben wird, wobei er mindestens
einige der Wärmeübertragungsröhren umgeht, um die Verteilung eines verbleibenden Kältemittels,
das durch die umgangenen Wärmeübertragungsröhren fließt, die in direkter Fluidkommunikation
mit dieser Stelle stehen, zu verbessern.
3. Kälteanlage (20) nach Anspruch 1 oder 2, wobei der mindestens eine von dem Kondensator
(24; 124; 224; 324; 424; 524) und dem Verdampfer (28) mindestens eine Verteilerstruktur
(30, 34) in Fluidkommunikation mit der Vielzahl von Wärmeübertragungsröhren (32, 36,
38, 40) aufweist, wobei die mindestens eine Verteilerstruktur mit mindestens einem
Trennelement versehen ist, das mindestens zwei Kammern (30A, 30B, 30C, 34A, 34B) innerhalb
der mindestens einen Verteilerstruktur bereitstellt, und wobei mindestens eine der
Kammern die Zapfstelle ist.
4. Kälteanlage (20) nach Anspruch 3, wobei das Trennelement eines von einer Trennplatte
(42), einem Rückschlagventil, einem Schwimmerventil (52; 80), einem Magnetventil,
einer Mündung mit einem Flüssigkeitsverschluss und einer Kombination davon ist.
5. Kälteanlage (20) nach Anspruch 1 oder 2, wobei der mindestens eine von dem Kondensator
(24; 124; 224; 324; 424; 524) und dem Verdampfer (28) mindestens eine Verteilerstruktur
(30, 34) in Fluidkommunikation mit der Vielzahl von Wärmeübertragungsröhren (32, 36,
38, 40) aufweist, wobei die mindestens eine Verteilerstruktur mit mindestens einem
Trennelement versehen ist, das mindestens zwei Kammern (30A, 30B, 30C, 34A, 34B) innerhalb
der mindestens einen Verteilerstruktur bereitstellt, und wobei mindestens eine der
Kammern die stromabwärtige Stelle (30C, 34B; 30, 25) ist.
6. Kälteanlage (20) nach Anspruch 1 oder 2, wobei der mindestens eine von dem Kondensator
(24; 124; 224; 324; 424; 524) und dem Verdampfer (28) eine Auslass-Kältemittelröhre
(25) aufweist, und wobei die Auslass-Kältemittelröhre die stromabwärtige Stelle (30C;
34B; 30; 25) ist.
7. Kälteanlage (20) nach einem der vorhergehenden Ansprüche, wobei das getrennte Kältemittel
mindestens teilweise von einer Umgehungsleitung (53; 56; 62; 78) geführt wird.
8. Kälteanlage (20) nach Anspruch 7, wobei die Umgehungsleitung (53; 56; 62; 78) mindestens
eines von externen und internen Elementen zur Verbesserung der Wärmeübertragung aufweist.
9. Kälteanlage (20) nach Anspruch 7, wobei die Umgehungsleitung (53; 56; 62; 78), die
mit mindestens einem von dem Kondensator (24; 124; 224; 324; 424; 524) und dem Verdampfer
(28) verknüpft ist, auf dem Luftströmungsweg positioniert ist, der sich über mindestens
einen von dem Kondensator und dem Verdampfer bewegt.
10. Kälteanlage (20) nach Anspruch 9, wobei die Umgehungsleitung (53; 56; 62; 78), die
mit mindestens einem von dem Kondensator (24; 124; 224; 324; 424; 524) und dem Verdampfer
(28) verknüpft ist, mit Bezug auf die Luftströmung stromaufwärts von mindestens einem
von dem Kondensator und dem Verdampfer positioniert ist.
11. Kälteanlage (20) nach einem der vorhergehenden Ansprüche, wobei jede der Vielzahl
von Wärmeübertragungsröhren (32, 36, 38, 40) eine Vielzahl von kleinen parallelen
internen Kanälen (100) aufweist, die ein Kältemittel auf parallelen Wegen in den Wärmeübertragungsröhren
führen, und wobei die parallelen internen Kanäle eine Mikrokanal-Wärmeübertragungsröhre
oder eine Minikanal-Wärmeübertragungsröhre erstellen.
12. Kälteanlage (20) nach einem der vorhergehenden Ansprüche, wobei es mehrere Zapfstellen
gibt.
13. Kälteanlage (20) nach einem der vorhergehenden Ansprüche, wobei es mehrere stromabwärtige
Stellen gibt.
14. Verfahren zum Betreiben einer Kälteanlage, umfassend folgende Schritte:
(1) Bereitstellen eines Kompressors (22) zum Abgeben eines komprimierten Kältemittels
an einen Kondensator (24; 124; 224; 324; 424; 524), wobei das Kältemittel von dem
Kondensator durch eine Expansionsvorrichtung (26) und von der Expansionsvorrichtung
durch einen Verdampfer (28) geht und von dem Verdampfer zu dem Kompressor zurückgeführt
wird; und
(2) Bereitstellen mindestens eines von dem Kondensator und dem Verdampfer, der eine
Vielzahl von Wärmeübertragungsröhren (32, 36, 38, 40) aufweist, die ein Kältemittel
stromabwärts allgemein parallel durchlassen;
gekennzeichnet durch folgenden Schritt:
(3) Identifizieren mindestens einer Stelle (30B, 34A, 34B, 34) innerhalb des Verdampfers
(28), die geeignet ist, um getrennte Dampf- und Flüssigkeitsphasen des Kältemittelgemischs
aufzunehmen, während das Kältemittel durch die Vielzahl von Wärmeübertragungsröhren fließt, und wobei mindestens ein Teil einer
getrennten Dampfphase an der Stelle abgezapft und an eine stromabwärtige Stelle (30C,
34B; 30; 25) abgegeben wird, wobei er mindestens einige der Wärmeübertragungsröhren
umgeht, um die Verteilung eines verbleibenden Kältemittels, das durch die umgangenen Wärmeübertragungsröhren fließt, die in direkter Fluidkommunikation
mit dieser Stelle stehen, zu verbessern.
15. Verfahren nach Anspruch 14, umfassend folgenden Schritt:
(4) Identifizieren mindestens einer Stelle (34A, 34B, 30B; 34) innerhalb des Kondensators
(24; 124; 224; 324; 424; 524), die geeignet ist, um getrennte Dampf- und Flüssigkeitsphasen
des Kältemittelgemischs aufzunehmen, während das Kältemittel durch die Vielzahl von
Wärmeübertragungsröhren fließt, und wobei mindestens ein Teil einer getrennten Flüssigkeitsphase
an der Stelle abgezapft und an eine stromabwärtige Stelle (30C, 34B; 30; 25) abgegeben
wird, wobei er mindestens einige der Wärmeübertragungsröhren umgeht, um die Verteilung
eines verbleibenden Kältemittels, das durch die umgangenen Wärmeübertragungsröhren
fließt, die in direkter Fluidkommunikation mit dieser Stelle stehen, zu verbessern.
1. Système réfrigérant (20) comprenant :
un condenseur (24 ; 124 ; 224 ; 324 ; 424 ; 524) ;
un compresseur (22) ;
un dispositif d'expansion (26) ; et
un évaporateur (28),
le compresseur permettant de délivrer un réfrigérant comprimé au condenseur, le réfrigérant
provenant dudit condenseur traversant le dispositif d'expansion et à partir dudit
dispositif d'expansion à travers l'évaporateur, et à partir dudit évaporateur étant
retourné audit compresseur ; et
au moins un dudit condenseur et dudit évaporateur comportant une pluralité de tubes
de transfert de chaleur (32, 36, 38, 40) qui font passer un réfrigérant en aval d'une
manière globalement parallèle ; et
au moins un emplacement (30B, 34A, 34B, 34) au sein dudit évaporateur (28) étant à
même de recevoir des phases séparées de vapeur et de liquides du mélange réfrigérant
alors que le réfrigérant s'écoule à travers la pluralité de tubes de transfert de
chaleur, caractérisé par le fait qu'au moins une partie d'une phase séparée de vapeur est alimentée à partir dudit emplacement
et délivrée à un emplacement aval (30C, 34B ; 30 ; 25) en contournant au moins une
partie des tubes de transfert de chaleur en vue d'améliorer la distribution d'un réfrigérant
résiduel s'écoulant à travers les tubes de transfert de chaleur contournés qui sont
en communication fluidique directe avec cet emplacement.
2. Système réfrigérant (20) selon la revendication 1, comprenant
au moins un emplacement (30B, 34A, 34B, 34) au sein dudit condenseur qui est à même
de recevoir des phases séparées de vapeur et de liquide du mélange réfrigérant alors
que le réfrigérant s'écoule à travers la pluralité de tubes de transfert de chaleur,
et au moins une partie d'une phase séparée de liquide étant alimentée à partir dudit
emplacement et délivrée vers un emplacement aval (30C, 34B ; 30 ; 25) en contournant
au moins une partie des tubes de transfert de chaleur afin d'améliorer la distribution
d'un réfrigérant résiduel s'écoulant à travers les tubes de transfert de chaleur contournés
qui sont en communication fluidique directe avec cet emplacement.
3. Système réfrigérant (20) selon la revendication 1 ou 2, dans lequel ledit au moins
un dudit condenseur (24 ; 124 ; 224 ; 324 ; 424 ; 524) et dudit évaporateur (28) comporte
au moins une structure de collecteur (30, 34) en communication fluidique avec ladite
pluralité de tubes de transfert de chaleur (32, 36, 38, 40), ladite au moins une structure
de collecteur étant dotée d'au moins un élément de séparation procurant au moins deux
chambres (30A, 30B, 30C, 34A, 34B) au sein de ladite au moins une structure de collecteur,
et au moins l'une desdites chambres étant ledit emplacement d'alimentation.
4. Système réfrigérant (20) selon la revendication 3, dans lequel ledit élément de séparation
est soit une plaque de séparation (42), un clapet antiretour, un régleur à flotteur
(52 ; 80), une électrovanne, un orifice doté d'un joint liquide ou une combinaison
de ceux-ci.
5. Système réfrigérant (20) selon la revendication 1 ou 2, dans lequel ledit au moins
un dudit condenseur (24 ; 124 ; 224 ; 324 ; 424 ; 524) et dudit évaporateur (28) comporte
au moins une structure de collecteur (30, 34) en communication fluidique avec ladite
pluralité de tubes de transfert de chaleur (32, 36, 38, 40), ladite au moins une structure
de collecteur étant dotée d'au moins un élément de séparation procurant au moins deux
chambres (30A, 30B, 30C, 34A, 34B) au sein de ladite au moins une structure de collecteur,
et au moins l'une desdites chambres étant ledit emplacement aval (30C, 34B ; 30 ;
25).
6. Système réfrigérant (20) selon la revendication 1 ou 2, dans lequel ledit au moins
un dudit condenseur (24 ; 124 ; 224 ; 324 ; 424 ; 524) et dudit évaporateur (28) comporte
un tube (25) de réfrigérant de sortie, et où ledit tube de réfrigérant de sortie est
ledit emplacement aval (30C ; 34B ; 30 ; 25).
7. Système réfrigérant (20) selon l'une quelconque des revendications précédentes, dans
lequel ledit réfrigérant séparé est au moins en partie porté par une conduite de dérivation
(53 ; 56 ; 62 ; 78).
8. Système réfrigérant (20) selon la revendication 7, dans lequel ladite conduite de
dérivation (53 ; 56 ; 62 ; 78) comporte au moins un élément parmi les éléments externes
et internes d'amélioration du transfert de chaleur.
9. Système réfrigérant (20) selon la revendication 7, dans lequel ladite conduite de
dérivation (53 ; 56 ; 62 ; 78) associée à au moins un élément parmi ledit condenseur
(24 ; 124 ; 224 ; 324 ; 424 ; 524) et ledit évaporateur (28) est positionnée dans
la voie d'écoulement d'air se déplaçant au-dessus d'au moins un élément parmi ledit
condenseur et ledit évaporateur.
10. Système réfrigérant (20) selon la revendication 9, dans lequel ladite conduite de
dérivation (53 ; 56 ; 62 ; 78) associée à au moins un élément parmi ledit condenseur
(24 ; 124 ; 224 ; 324 ; 424 ; 524) et ledit évaporateur (28) est positionnée en amont
d'au moins un élément parmi ledit condenseur et ledit évaporateur, par rapport à l'écoulement
d'air.
11. Système réfrigérant (20) selon l'une quelconque des revendications précédentes, dans
lequel chacun desdits tubes de transfert de chaleur (32, 36, 38, 40) comporte un ensemble
de petits canaux internes parallèles (100) portant le réfrigérant dans des voies parallèles
au sein desdits tubes de transfert de chaleur, et dans lequel lesdits canaux internes
parallèles créent un tube de transfert de chaleur à microcanal ou un tube de transfert
de chaleur à minicanal.
12. Système réfrigérant (20) selon l'une quelconque des revendications précédentes, dans
lequel il existe de multiples emplacements d'alimentation.
13. Système réfrigérant (20) selon l'une quelconque des revendications précédentes, dans
lequel il existe de multiples emplacements aval.
14. Procédé d'actionnement d'un système réfrigérant, comprenant les étapes suivantes :
(1) prendre un compresseur (22) pour délivrer un réfrigérant comprimé vers un condenseur
(24 ; 124 ; 224 ; 324 ; 424 ; 524), le réfrigérant provenant dudit condenseur passant
à travers un dispositif d'expansion (26), et à partir dudit dispositif d'expansion
à travers un évaporateur (28), et à partir dudit évaporateur, étant retourné vers
ledit compresseur ; et
(2) prendre au moins un élément parmi ledit condenseur et ledit évaporateur comportant
une pluralité de tubes de transfert de chaleur (32, 36, 38, 40) qui font passer un
réfrigérant en aval d'une manière globalement parallèle ;
caractérisé par l'étape suivante :
(3) identifier au moins un emplacement (34A, 34B, 30B ; 34) au sein dudit évaporateur
(28) susceptible de recevoir les phases séparées de vapeur et de liquide du mélange
réfrigérant alors que le réfrigérant s'écoule à travers la pluralité de tubes de transfert
de chaleur, et au moins une partie d'une phase séparée de vapeur étant alimentée à
partir dudit emplacement et délivrée à un emplacement aval (30C, 34B ; 30 ; 25) en
contournant au moins une partie des tubes de transfert de chaleur, afin d'améliorer
la distribution d'un réfrigérant résiduel s'écoulant à travers les tubes de transfert
de chaleur contournés qui sont en communication fluidique directe avec cet emplacement.
15. Procédé selon la revendication 14, comprenant l'étape suivante :
(4) identifier au moins un emplacement (34A, 34B, 30B ; 34) au sein dudit condenseur
(24 ; 124 ; 224 ; 324 ; 424 ; 524) susceptible de recevoir des phases séparées de
vapeur et de liquide de mélange réfrigérant alors que le réfrigérant s'écoule à travers
la pluralité de tubes de transfert de chaleur, et au moins une partie de la phase
séparée de liquide étant alimentée à partir dudit emplacement et délivrée en un emplacement
aval (30C, 34B ; 30 ; 25) en contournant au moins une partie des tubes de transfert
afin d'améliorer la distribution d'un réfrigérant résiduel s'écoulant à travers les
tubes de transfert de chaleur contournés qui sont en communication fluidique directe
avec cet emplacement.