U.S. patent application number 16/960671 was filed with the patent office on 2020-10-22 for cooling circuit section and cooling circuit.
The applicant listed for this patent is Carrier Corporation. Invention is credited to Micael Antonsson, Philippe Gastaldi, Sascha Hellmann, Barnabe Landron, Nicolas Pondicq-Cassou.
Application Number | 20200333053 16/960671 |
Document ID | / |
Family ID | 1000004956479 |
Filed Date | 2020-10-22 |
United States Patent
Application |
20200333053 |
Kind Code |
A1 |
Hellmann; Sascha ; et
al. |
October 22, 2020 |
COOLING CIRCUIT SECTION AND COOLING CIRCUIT
Abstract
Cooling circuit section (2), intended for the circulation of a
refrigerant, said cooling circuit section (2) comprising:--at least
two compressor assemblies (30), fluidically connected in parallel,
each compressor assembly (30) comprising:--a compressor (40)
configured to receive a low-pressure refrigerant having a first
pressure, and for increasing the pressure of the low-pressure
refrigerant so as to produce a compressed refrigerant having a
second pressure that is greater than the first pressure, the
compressed refrigerant comprising oil,--an individual oil separator
(42) comprising an inlet (58) fluidically connected to the
compressor (40) so as to receive the compressed refrigerant from
the compressor (40), each individual oil separator (42) being
configured to separate a first fraction of oil from the compressed
refrigerant, the cooling circuit section (2) further comprising a
common oil separator (32).
Inventors: |
Hellmann; Sascha; (Hochheim,
Hessen, DE) ; Pondicq-Cassou; Nicolas; (Saint Cyr sur
Mer, FR) ; Gastaldi; Philippe; (Gemenos, FR) ;
Antonsson; Micael; (Varberg, SE) ; Landron;
Barnabe; (Marseille, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Carrier Corporation |
Palm Beach Gardens |
FL |
US |
|
|
Family ID: |
1000004956479 |
Appl. No.: |
16/960671 |
Filed: |
January 12, 2018 |
PCT Filed: |
January 12, 2018 |
PCT NO: |
PCT/EP2018/050770 |
371 Date: |
July 8, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F25B 31/004 20130101;
F25B 2400/075 20130101; F25B 2600/2513 20130101; F25B 49/02
20130101; F25B 2400/23 20130101; F25B 43/02 20130101; F25B 2339/047
20130101; F25B 2500/16 20130101 |
International
Class: |
F25B 31/00 20060101
F25B031/00; F25B 43/02 20060101 F25B043/02; F25B 49/02 20060101
F25B049/02 |
Claims
1. Cooling circuit section, intended for the circulation of a
refrigerant, said cooling circuit section comprising: at least two
compressor assemblies, fluidically connected in parallel, each
compressor assembly comprising: a compressor configured to receive
a low-pressure refrigerant having a first pressure, and for
increasing the pressure of the low-pressure refrigerant so as to
produce a compressed refrigerant having a second pressure that is
greater than the first pressure, the compressed refrigerant
comprising oil, an individual oil separator comprising an inlet
fluidically connected to the compressor so as to receive the
compressed refrigerant from the compressor, each individual oil
separator being configured to separate a first fraction of oil from
the compressed refrigerant, the individual oil separator further
comprising: a refrigerant outlet, through which the compressed
refrigerant is intended to be discharged from the individual oil
separator after separation of the first fraction of oil and an oil
outlet, through which the first fraction of oil is intended to be
discharged from the individual oil separator, the individual oil
separator being further configured to return the first fraction of
oil to the compressor, the cooling circuit section further
comprising a common oil separator fluidically connected to the
refrigerant outlet of each individual oil separator so as to
receive the compressed refrigerant from each of the compressor
assemblies, the common oil separator being configured to separate a
second fraction of oil from the compressed refrigerant.
2. Cooling circuit section according to claim 1, wherein the common
oil separator comprises an inlet, fluidically connected to the
compressor assemblies so as to receive the compressed refrigerant
from the compressor assemblies, a refrigerant outlet, through which
the compressed refrigerant is intended to be discharged from the
common oil separator after separation of the second fraction of
oil, and an oil outlet, through which the second fraction of oil is
intended to be discharged from the common oil separator.
3. Cooling circuit section according to claim 1, wherein the
cooling circuit section further comprises a common feedback tube
fluidically connecting the common oil separator to each of the
compressors so as to feed the second fraction of oil back into the
compressors.
4. Cooling circuit section according to claim 3, wherein the common
feedback tube comprises an expansion valve configured to decrease
the pressure of the second fraction of oil from the second pressure
to the first pressure.
5. Cooling circuit section according to claim 1, wherein each
compressor assembly comprises an individual feedback tube
fluidically connecting the oil outlet of the individual oil
separator to the compressor so as to feed the first fraction of oil
back into the compressor of the compressor assembly.
6. Cooling circuit section according to claim 1, wherein the
individual feedback tube comprises an expansion device configured
to decrease the pressure of the first fraction of oil from the
second pressure to the first pressure.
7. Cooling circuit section according to claim 1, wherein the common
oil separator is a coalescence oil separator or a centrifugal oil
separator.
8. Cooling circuit section according to claim 1, wherein each of
the individual oil separators is configured to separate the oil
from the refrigerant based on differences in the densities of the
refrigerant and the oil.
9. Cooling circuit section according to claim 8, wherein the
individual oil separators are chosen among a fluid speed decrease
oil separator, configured to decrease the speed of the fluid fed
into the oil separator and a fluid direction modification oil
separator, configured to change the direction of the fluid fed into
the oil separator.
10. Cooling circuit section according to claim 1, wherein the
compressor of each compressor assembly is a hermetic
compressor.
11. Cooling circuit section according to claim 1, wherein the
refrigerant is carbon dioxide.
12. Cooling circuit comprising a cooling circuit section according
to claim 1, the cooling circuit further comprising a heat exchanger
device configured to cool the refrigerant, an expansion valve and
an evaporator device.
13. Cooling circuit according to claim 12, wherein the heat
exchanger device, the expansion valve and the evaporator device are
connected in series, the heat exchanger device being connected to
an outlet of the common oil separator and the evaporator device
being connected to an inlet of the compressor assemblies.
14. Cooling circuit according to claim 12, wherein the heat
exchanger device is a condenser configured to cool the refrigerant
such that the refrigerant condenses into a liquid state.
15. Cooling circuit according to claim 12, wherein the heat
exchanger device is a gas cooler configured to cool the refrigerant
such that the refrigerant remains in the gaseous state.
16. Cooling circuit section according to claim 11, wherein the
refrigerant is carbon dioxide R744.
Description
[0001] The present invention relates to a cooling circuit section
and a cooling circuit.
[0002] The present invention in particular relates to the field of
refrigeration units for commercial and residential
applications.
[0003] U.S. Pat. No. 4,506,523 discloses a cooling circuit section
for a refrigeration system comprising two compressors connected in
parallel in a fluid manner. A common discharge header of the
compressors is connected to a common oil separation system
including an oil separator unit with an oil reservoir. Oil
separated from the refrigerant in the separator unit and collected
in the oil reservoir is returned directly into the compressors via
an oil return line connecting the oil separation system to the
compressors.
[0004] However, the cooling circuit section as described above has
several drawbacks.
[0005] Indeed, the inventors of the present invention have found
that, due to the particular structure of the system with only one
common oil separator feeding the oil back into both compressors,
the exact amount of oil fed back into each of the compressors is
difficult to control. This can be detrimental for the safe
operation of the compressors, which requires a sufficient amount of
oil. Furthermore, the total amount of oil filtered from the
refrigerant in prior art systems is not entirely satisfactory.
[0006] The present invention aims to resolve the aforementioned
problems by providing a cooling circuit section with improved
operational safety.
[0007] To that end, the invention relates to a cooling circuit
section, intended for the circulation of a refrigerant, said
cooling circuit section comprising: [0008] at least two compressor
assemblies, fluidically connected in parallel, each compressor
assembly comprising: [0009] a compressor configured to receive a
low-pressure refrigerant having a first pressure, and for
increasing the pressure of the low-pressure refrigerant so as to
produce a compressed refrigerant having a second pressure that is
greater than the first pressure, the compressed refrigerant
comprising oil, [0010] an individual oil separator comprising an
inlet fluidically connected to the compressor so as to receive the
compressed refrigerant from the compressor, each individual oil
separator being configured to separate a first fraction of oil from
the compressed refrigerant, [0011] the individual oil separator
further comprising: [0012] a refrigerant outlet, through which the
compressed refrigerant is intended to be discharged from the
individual oil separator after separation of the first fraction of
oil and [0013] an oil outlet, through which the first fraction of
oil is intended to be discharged from the individual oil separator,
the individual oil separator being further configured to return the
first fraction of oil to the compressor, [0014] the cooling circuit
section further comprising a common oil separator fluidically
connected to the refrigerant outlet of each individual oil
separator so as to receive the compressed refrigerant from each of
the compressor assemblies, the common oil separator being
configured to separate a second fraction of oil from the compressed
refrigerant.
[0015] According to advantageous but not mandatory aspects of the
invention, such a cooling circuit section may comprise one or
several of the following features, taken in any technically
possible combination: [0016] the common oil separator comprises an
inlet, fluidically connected to the compressor assemblies so as to
receive the compressed refrigerant from the compressor assemblies,
a refrigerant outlet, through which the compressed refrigerant is
intended to be discharged from the common oil separator after
separation of the second fraction of oil, and an oil outlet,
through which the second fraction of oil is intended to be
discharged from the common oil separator; [0017] the cooling
circuit section further comprises a common feedback tube
fluidically connecting the common oil separator to each of the
compressors so as to feed the second fraction of oil back into the
compressors; [0018] the common feedback tube comprises an expansion
valve configured to decrease the pressure of the second fraction of
oil from the second pressure to the first pressure; [0019] each
compressor assembly comprises an individual feedback tube
fluidically connecting the oil outlet of the individual oil
separator to the compressor so as to feed the first fraction of oil
back into the compressor of the compressor assembly; [0020] the
individual feedback tube comprises an expansion device configured
to decrease the pressure of the first fraction of oil from the
second pressure to the first pressure; [0021] the common oil
separator is a coalescence oil separator or a centrifugal oil
separator; [0022] each of the individual oil separators is
configured to separate the oil from the refrigerant based on
differences in the densities of the refrigerant and the oil; [0023]
the individual oil separators are chosen among a fluid speed
decrease oil separator, configured to decrease the speed of the
fluid fed into the oil separator and a fluid direction modification
oil separator, configured to change the direction of the fluid fed
into the oil separator; [0024] the compressor of each compressor
assembly is a hermetic compressor; [0025] the refrigerant is carbon
dioxide, preferably carbon dioxide R744.
[0026] The invention further relates to a cooling circuit
comprising a cooling circuit section as described above, the
cooling circuit further comprising a heat exchanger device
configured to cool the refrigerant, an expansion valve and an
evaporator device.
[0027] According to advantageous but not mandatory aspects of the
invention, such a cooling circuit may comprise one or several of
the following features, taken in any technically possible
combination: [0028] the heat exchanger device, the expansion valve
and the evaporator device are connected in series, the heat
exchanger device being connected to an outlet of the common oil
separator and the evaporator device being connected to an inlet of
the compressor assemblies; [0029] the heat exchanger device is a
condenser configured to cool the refrigerant such that the
refrigerant condenses into a liquid state; [0030] the heat
exchanger device is a gas cooler configured to cool the refrigerant
such that the refrigerant remains in the gaseous state.
[0031] The invention and other advantages thereof will become more
clearly apparent in the light of the description which follows of
an embodiment of a cooling circuit section according to the
invention, only given as an example and made with reference to the
appended drawings wherein:
[0032] FIG. 1 is a schematic diagram of a cooling circuit
comprising a cooling circuit section according to the invention,
and
[0033] FIG. 2 is a schematic diagram of an individual oil separator
of the cooling circuit of FIG. 1.
[0034] FIG. 1 shows a cooling circuit 1 intended for the
circulation of a refrigerant. In this figure, the intended
circulation direction of the refrigerant in the cooling circuit is
indicated by arrows.
[0035] The refrigerant is a fluid adapted for transporting heat
from a volume that is to be cooled to an environment.
[0036] The refrigerant is of a type as known as such in the art.
For example, the fluid is a hydrochlorofluorocarbon fluid. In
another example, the refrigerant is carbon dioxide (for example
R744). However, any other adapted type of refrigerant may be
used.
[0037] As shown in FIG. 1, the cooling circuit 1 comprises a
cooling circuit section 2.
[0038] The cooling circuit section 2 comprises an inlet tube 20, an
outlet tube 22, and at least two compressor assemblies 30 and a
common oil separator 32 disposed there-between.
[0039] The inlet tube 20 is intended for the circulation of a
refrigerant having a first pressure and the outlet tube 22 is
intended for the circulation of a refrigerant having a second
pressure, the second pressure being greater than the first
pressure. The compressor assemblies 30 are configured to increase
the pressure of the refrigerant from the first pressure to the
second pressure.
[0040] Preferably, the second pressure is strictly greater than the
first pressure.
[0041] In the example of FIG. 1, the cooling circuit section 2
comprises three compressor assemblies 30. However, a different
number of compressor assemblies 30 may be used depending on the
needs.
[0042] The compressor assemblies 30 are fluidically connected in
parallel. More particularly, each compressor assembly 30 is
fluidically connected to the inlet tube 20 of the cooling circuit
section 2 such that it receives at least a portion of the
refrigerant circulating in the inlet tube 20.
[0043] Each compressor assembly 30 comprises a compressor 40, an
individual oil separator 42 and an individual feedback tube 44.
[0044] The compressor 40 is for example hermetic compressor.
[0045] A hermetic compressor is a compressor in which the motor and
the mechanical compression parts are arranged in a hermetically
closed casing. The casing is more particularly a steel casing.
[0046] The only openings in the casing are the inlet 50 and the
outlet 54 which are configured to receive or discharging the
refrigerant. In particular, there is no additional opening for
feeding additional fluids, such as oil, into the compressor.
[0047] The casing of the hermetic compressor is not configured to
be opened.
[0048] The compressor 40 comprises an inlet 50 for the refrigerant,
a compression unit 52 for compressing the refrigerant from the
first pressure to the second pressure and an outlet 54 for the
refrigerant.
[0049] Each inlet 50 is fludically connected to the inlet tube
20.
[0050] The first pressure depends on the application requirements.
The first pressure is for example comprised between 12 and 60 bar,
and typically equal to 28 bar.
[0051] The second pressure depends typically on the ambient air
condition. The second pressure is for example comprised between 45
and 130 bar.
[0052] In the following, the refrigerant having the first pressure
is referred to as "low-pressure refrigerant" and the refrigerant
having the second pressure is referred to as "compressed
refrigerant".
[0053] The compression unit 52 of the compressor 40 comprises
mechanical moveable parts (not shown) which are lubricated by oil.
The oil is of any type adapted for the use in refrigerant
compressors. It may be, for example, a mineral or a vegetable
oil.
[0054] During the operation of the compression unit 52, a fraction
of the oil used for the lubrication of the compressor 40 mixes with
the refrigerant. Therefore, the compressed refrigerant exiting the
compressor 40 at the outlet 54 comprises some oil.
[0055] The amount of oil introduced into the refrigerant is, for
example, a function of the rotation frequency of the compressor 40
and/or of a working point of the compressor 40.
[0056] The individual oil separator 42 is configured to separate a
first fraction of the oil contained in the compressed refrigerant
and for returning this first fraction of oil into the compressor 40
through the individual feedback tube 44.
[0057] The individual oil separator 42 is fluidically connected to
the compressor 40 so as to receive the compressed refrigerant from
the compressor 40. In particular, an inlet 58 of the individual oil
separator is fluidically connected, for example via a connection
tube 56, to the outlet 54 of the compressor 40.
[0058] The individual oil separator 42 comprises, in the example of
FIG. 2, a separation unit 59, a refrigerant outlet 60 and an oil
outlet 62.
[0059] The individual oil separator 42 is configured to separate,
in the separation unit 59, a first fraction of oil from the
compressed refrigerant such that the first fraction of oil exits
the individual oil separator 42 through the oil outlet 62 and the
remaining compressed refrigerant exits the individual oil separator
42 through the refrigerant outlet 60.
[0060] The compressed refrigerant exiting the individual oil
separator still comprises oil. More particularly, the amount of oil
remaining in the compressed refrigerant corresponds to the amount
of oil in the compressed refrigerant entering the individual oil
separator 42 reduced by the first fraction of oil removed by the
individual oil separator 42.
[0061] The individual oil separator 42 is of any type adapted to
separating oil from a refrigerant.
[0062] According to one embodiment, the individual oil separator 42
is configured to separate the oil from the refrigerant based on the
differences in the densities of the refrigerant and the oil.
[0063] According to one example, the oil separator 42 is a fluid
direction modification oil separator, which is configured to modify
the trajectory of the refrigerant so as to separate the lighter
molecules from the heavier ones. In fact, when the trajectory of
the fluid is modified, the heavier molecules in the fluid tend to
continue, due to their inertia, on their initial trajectory,
whereas lighter molecules tend to change their trajectory. The
light molecules are thus separated from the heavy molecules. Such
fluid direction modification oil separators are known in the
art.
[0064] For example, the separation unit 59 of the individual oil
separator 42 comprises a T-shaped tube comprising a main tube and
two deviation tubes fluidically connected to the deviation tube.
Each deviation tube extends substantially perpendicular to the main
tube. A first deviation tube of the separation unit 59 is connected
to the refrigerant outlet 60, while the second deviation tube of
the separation unit 59 is connected to the oil outlet 62.
[0065] According to an alternative embodiment, the individual oil
separator 42 is a fluid speed decrease oil separator configured to
decrease the speed of the fluid received therein so as to separate
the oil from the refrigerant. As known, the speed decrease of a
considered fluid within the oil separator 42 depends on its
density. Fluid speed decrease oil separators are known in the
art.
[0066] In the example shown in FIG. 2, the individual oil separator
42 further comprises a casing 57 and an inspection glass 61. The
inspection glass 61 comprises a glass inserted into an opening of
the casing 57. The inspection glass 61 is configured to visualize
the oil flow out of the individual oil separator 42.
[0067] As mentioned above, the individual oil separator 42 is
configured to feed the first fraction of oil back to the compressor
40. In particular, the oil outlet 62 of the individual oil
separator 42 is fluidically connected, via the individual feedback
tube 44, to a tube communicating with the inlet 50 of the
compressor 40.
[0068] In the example shown in the figures, the individual feedback
tube 44 comprises an expansion device 63 configured to decrease the
pressure of the first fraction of oil from the second pressure to
the first pressure. In the example shown in the figures, the
expansion device is an expansion valve. However, any other adapted
expansion device may be used, for example a capillary tube.
[0069] The refrigerant outlet 60 of the individual oil separator 42
of each compressor assembly is fluidically connected to the common
oil separator 32.
[0070] More particularly, each compressor assembly 30 comprises an
individual connection tube 64 having an inlet connected to the
refrigerant outlet 60 of the individual oil separator 42. The
cooling circuit section 2 further comprises a common connection
tube 66 having an inlet connected to an outlet of each of the
individual connection tubes 64, and an outlet connected to the
common oil separator 32.
[0071] As shown in FIG. 1, the common oil separator 32 comprises an
inlet 70, fluidically connected to the compressor assemblies 30 so
as to receive the compressed refrigerant from the compressor
assemblies 30, a separation unit (not shown), configured to
separate a second fraction of oil from the compressed refrigerant,
a refrigerant outlet 72, through which the compressed refrigerant
is intended to be discharged from the common oil separator 32 after
separation of the second fraction of oil, and an oil outlet 74,
through which the second fraction of oil is intended to be
discharged from the common oil separator 32. More particularly, the
refrigerant outlet 72 is fluidically connected with the outlet tube
22 of the cooling circuit section.
[0072] The common oil separator 32 may be of any other type adapted
for separating oil from the refrigerant. More particularly, the
common oil separator 32 is configured to separate the second
fraction of oil from the refrigerant.
[0073] Preferably, for example in order to save cost, the
individual oil separators 42 are of a different type than the
common oil separator 32. In particular, the individual oil
separators 42 are configured to separate a significantly smaller
amount of oil from the refrigerant than the common oil separator
32.
[0074] The common oil separator 32 is, for example, a coalescence
oil separator.
[0075] The coalescence oil separator is an oil separator configured
to operate according to the coalescence principle. The coalescence
principle is the accumulation of droplets of two identical
substances which are dispersed in a fluid by reunification of the
identical substances.
[0076] In an alternative embodiment, the common oil separator 32 is
a centrifugal oil separator.
[0077] The centrifugal oil separator is an oil separator configured
to separate oil from the refrigerant by centrifugation. In
particular, due to the density difference between the oil and the
refrigerant, the oil is separated by means of a rotating cylinder
inside the centrifugal oil separator. Such centrifugal oil
separators are known in the art.
[0078] The cooling circuit section 2 further comprises a common
feedback tube 76 fluidically connecting the common oil separator 32
to each of the compressors 40 so as to feed the second fraction of
oil back to the compressors 40.
[0079] In particular, the oil outlet 62 of the common oil separator
32 is fluidically connected, via the common feedback tube 76, to
the inlet tube 20 of the cooling circuit section 2.
[0080] In the example shown in the figures, the common feedback
tube 76 comprises an expansion device 78 configured to decrease the
pressure of the second fraction of oil from the second pressure to
the first pressure. In the example shown in the figures, the
expansion device 78 is an expansion valve. However, any other
adapted expansion device may be used, for example a capillary
tube.
[0081] In the example shown in FIG. 1, the cooling circuit section
2 forms part of a cooling circuit 1, further comprising a heat
exchanger device 80, an expansion valve 81 and an evaporator device
82.
[0082] The cooling circuit section 2 and the heat exchanger device
80 may, for example, form a condenser unit. The condenser unit is
configured to compress and to condense the refrigerant.
[0083] The condenser unit is, for example, configured to be
installed distant from the evaporator device. For example, in the
case of a cooling circuit 1 implemented in a supermarket, the
condenser unit may be installed in an equipment room and the
evaporator device 82 in a customer area.
[0084] The heat exchanger device 80 comprises an inlet 83,
fluidically connected to the outlet tube 22 of the cooling circuit
section 2, an outlet 84 and a heat exchanging unit (not
represented) arranged there-between.
[0085] For example, the heat exchanging unit comprises tubes which
are fluidically connected to the inlet 83 and the outlet 84 and at
least one fan configured to provide an air circulation across the
tubes.
[0086] According to one example, the refrigerant is intended to
enter the heat exchanger device 80 in a gaseous state.
[0087] The heat exchanger device 80 is configured to cool the
refrigerant. In particular, the heat exchanger device 80 is
configured to reject heat from the refrigerant into the environment
of the heat exchanger device 80. The refrigerant at the outlet 84
has a temperature strictly smaller than a temperature of the
refrigerant at the inlet 83.
[0088] According to one embodiment, the heat exchanger device 80 is
a condenser. In this case, the heat exchanging unit is a
condensation unit. The condenser is configured to cool the
refrigerant in such a manner that the refrigerant condenses from a
gaseous state into a liquid state. The condenser is, in this
example, configured to cool a refrigerant at a pressure inferior to
a critical pressure point. In this embodiment, the refrigerant is
intended to exit the heat exchanger device 80 in a liquid
state.
[0089] In another example, the heat exchanger device 80 is a gas
cooler. The gas cooler is configured to cool the refrigerant in
such a manner that it remains in the gaseous state. In this case,
the refrigerant is intended to exit the heat exchanger device 80 in
a gaseous state.
[0090] According to one example, the refrigerant is carbon dioxide
and the heat exchanger device 80 operates with the refrigerant in a
supercritical state. In particular, the refrigerant has for example
a pressure greater than 73 bar. In this example, the heat exchanger
device 80 is configured to provide the refrigerant in a
supercritical gaseous state at the outlet 84.
[0091] The outlet 84 of the heat exchanger device 80 is fluidically
connected to an inlet 85 of the expansion valve 81. The expansion
valve 81 is configured to expand the refrigerant. It is configured
to decrease the pressure of the refrigerant from the second
pressure to the first pressure.
[0092] An outlet 86 of the expansion valve 81 is fluidically
connected to the evaporator device 82.
[0093] The evaporator device 82 comprises an inlet 88, an outlet 90
and an evaporator unit (not represented) arranged there-between.
For example, the evaporator device 82 comprises heat exchange tubes
(not represented).
[0094] The evaporator device 82 is configured to evaporate the
refrigerant by heat exchange between the refrigerant circulating
through the evaporator device 82, and more particularly in the heat
exchange tubes, and a cooling volume (not represented). The cooling
volume is for example an inside of a refrigerator, a freezer, a
cooling cabinet such as multideck cabinet, for example in a
supermarket, or self-service counter, for example in a supermarket,
a cold room or a refrigerated warehouse.
[0095] The outlet 90 of the evaporator device 82 is connected to
the inlet tube 20 of the cooling circuit section 2.
[0096] The cooling circuit section according to the invention is
particularly advantageous. In particular, the combination of
individual oil separators 42 and a common oil separator 32 allows
for a safe operation of the system, and more particularly of the
compressors, thanks to a simple and reliable management of the oil
management in the cooling circuit section.
[0097] In particular, within the cooling circuit 1 of the
invention, the oil level in each compressor 40 is automatically
maintained at a safe operational level, as each compressor 40
receives, via the individual feedback tube 44, a fraction of oil
released into the refrigerant during compression of the refrigerant
by the compressor 40.
[0098] For example, if one of the compressors 40 operates at a high
frequency, a high amount of oil is released into the compressed
refrigerant in this compressor 40. The corresponding individual oil
separator 42 is then configured to feed back this large amount of
oil directly into the corresponding compressor 40, in order to
ensure that the compressor 40 disposes of enough oil for
lubrication.
[0099] This is particularly important in the case of a hermetic
compressor, in which, due to the hermetic closure of the casing, it
is not possible to feed new oil into the compressor via its casing
from outside of the cooling circuit.
[0100] Furthermore, the cooling circuit section 2 presents a very
high efficiency for separating the oil from the refrigerant, since
the cooling circuit 1 is configured to separate the oil from the
refrigerant in two stages, namely in the individual oil separator
42 and the common oil separator 32. As a consequence, with the
cooling circuit 1 of the invention, at the fluid outlet 72 of the
common oil separator 32, no or almost no oil is left in the
refrigerant after it leaves the common oil separator 32. The fact
that the refrigerant circulating through the heat exchanger device
80 and the evaporator device 82 only contains very small amounts of
oil is further advantageous, since it improves the thermodynamic
performance of the refrigerant in the cooling circuit 1.
* * * * *