U.S. patent application number 13/566543 was filed with the patent office on 2013-02-07 for refrigerant circuit.
This patent application is currently assigned to VISTEON GLOBAL TECHNOLOGIES, INC.. The applicant listed for this patent is Hans Hammer, Peter Heyl, Martin Hoetzel, Christian Rebinger, Dirk Schroeder. Invention is credited to Hans Hammer, Peter Heyl, Martin Hoetzel, Christian Rebinger, Dirk Schroeder.
Application Number | 20130031922 13/566543 |
Document ID | / |
Family ID | 47554136 |
Filed Date | 2013-02-07 |
United States Patent
Application |
20130031922 |
Kind Code |
A1 |
Heyl; Peter ; et
al. |
February 7, 2013 |
REFRIGERANT CIRCUIT
Abstract
The invention includes a refrigerant circuit for a cooling
operation and a heat pump operation. The refrigerant circuit has a
high pressure area and a low pressure area, including at least one
heat source/heat sink, a compressor, an expansion device, at least
one thermal interior space module, and an internal heat exchanger.
The internal heat exchanger has a high pressure side part and a low
pressure side part, wherein the high pressure side part is disposed
between the expansion device and the heat source/heat sink. The
invention also includes at least one metering device through which
the high pressure side part of the internal heat exchanger is
operable during the heat pump operation at a medium pressure level
intermediate a pressure level in the high pressure area and a
pressure level in the low pressure area of the refrigerant
circuit.
Inventors: |
Heyl; Peter; (Koln, DE)
; Rebinger; Christian; (Ingolstadt, DE) ;
Schroeder; Dirk; (Manching, DE) ; Hammer; Hans;
(Pfaffenhofen, DE) ; Hoetzel; Martin; (Ratingen,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Heyl; Peter
Rebinger; Christian
Schroeder; Dirk
Hammer; Hans
Hoetzel; Martin |
Koln
Ingolstadt
Manching
Pfaffenhofen
Ratingen |
|
DE
DE
DE
DE
DE |
|
|
Assignee: |
VISTEON GLOBAL TECHNOLOGIES,
INC.
Van Buren Twp.
MI
|
Family ID: |
47554136 |
Appl. No.: |
13/566543 |
Filed: |
August 3, 2012 |
Current U.S.
Class: |
62/222 ;
62/190 |
Current CPC
Class: |
B60H 2001/00942
20130101; F25B 2600/2513 20130101; B60H 1/00907 20130101; F25B
41/04 20130101; F25B 30/02 20130101; F25B 2341/066 20130101 |
Class at
Publication: |
62/222 ;
62/190 |
International
Class: |
F25B 41/04 20060101
F25B041/04; F25B 49/02 20060101 F25B049/02 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 5, 2011 |
DE |
10 2011 109 506.7 |
Claims
1. A refrigerant circuit for a vehicle, comprising: a compressor
configured to compress a refrigerant; an internal heat exchanger in
fluid communication with the compressor to receive the refrigerant
therein, the internal heat exchanger including a high pressure side
part and a low pressure side part, wherein the high pressure side
part is in fluid communication with at least one additional heat
exchanger; and at least one metering device configured to control a
pressure level of the refrigerant, the at least one metering device
in fluid communication with the internal heat exchanger, wherein
the at least one metering device permits the high pressure side
part of the internal heat exchanger to receive the refrigerant
during a heat pump operation of the refrigerant circuit between a
pressure level at which the refrigerant exits the compressor and a
pressure level at which the refrigerant enters the compressor.
2. The refrigerant circuit of claim 1, wherein the high pressure
side part of the internal heat exchanger is in fluid communication
with an expansion device.
3. The refrigerant circuit of claim 1, wherein the at least one
metering device is configured to decrease the pressure level of the
refrigerant during the heat pump operation of the refrigerant
circuit and maintain the pressure level of the refrigerant during a
cooling operation thereof.
4. The refrigerant circuit of claim 1, wherein the at least one
metering device is at least one of a damper, a conduit, and a
controllable expansion device.
5. The refrigerant circuit of claim 4, wherein the conduit has a
cross-section which facilitates a decrease in the pressure level of
the refrigerant during the heat pump operation of the refrigerant
circuit and maintains the pressure level of the refrigerant during
a cooling operation thereof.
6. The refrigerant circuit of claim 1, wherein the high pressure
side part of the internal heat exchanger during the heat pump
operation of the refrigerant circuit is upstream of the at least
one metering device.
7. The refrigerant circuit of claim 1, wherein the at least one
additional heat exchanger is at least one of a condenser/gas cooler
and a glycol heat exchanger/chiller.
8. The refrigerant circuit of claim 1, further comprising a
refrigerant storage area disposed between the internal heat
exchanger and the at least one additional heat exchanger.
9. The refrigerant circuit of claim 8, wherein the refrigerant
storage area during the heat pump operation of the refrigerant
circuit is downstream of the high pressure side part of the
internal heat exchanger.
10. The refrigerant circuit of claim 1, wherein the at least one
additional heat exchanger is operable with at least one of water,
air, exhaust gas, electronics, heat storage, solar heat, and solar
energy.
11. A refrigerant circuit for a vehicle, comprising: a compressor
configured to compress a refrigerant; an internal heat exchanger in
fluid communication with the compressor to receive the refrigerant
therein, the internal heat exchanger including a high pressure side
part and a low pressure side part, wherein the high pressure side
part is in fluid communication with a condenser/gas cooler and a
heat exchanger/chiller; and at least one controllable expansion
device configured to control a pressure level of the refrigerant,
the at least one controllable expansion device in fluid
communication with the internal heat exchanger, wherein the at
least one controllable expansion device permits the high pressure
side part of the internal heat exchanger to receive the refrigerant
during a heat pump operation of the refrigerant circuit between a
pressure level at which the refrigerant exits the compressor and a
pressure level at which the refrigerant enters the compressor.
12. The refrigerant circuit of claim 11, wherein the high pressure
side part of the internal heat exchanger is in fluid communication
with an additional expansion device.
13. The refrigerant circuit of claim 11, wherein the at least one
controllable expansion device is configured to decrease the
pressure level of the refrigerant during the heat pump operation of
the refrigerant circuit and maintain the pressure level of the
refrigerant during a cooling operation thereof.
14. The refrigerant circuit of claim 11, wherein the high pressure
side part of the internal heat exchanger during the heat pump
operation of the refrigerant circuit is upstream of the at least
one controllable expansion device.
15. The refrigerant circuit of claim 11, wherein the at least one
controllable expansion device is disposed between the internal heat
exchanger and at least one of the condenser/gas cooler and the heat
exchanger/chiller.
16. The refrigerant circuit of claim 11, further comprising a
refrigerant storage area disposed between the internal heat
exchanger and at least one of the condenser/gas cooler and the heat
exchanger/chiller.
17. The refrigerant circuit of claim 11, wherein the condenser/gas
cooler and the heat exchanger/chiller are connected in one of
parallel and series.
18. The refrigerant circuit of claim 11, wherein the heat
exchanger/chiller is in heat exchange relationship with a motor
refrigerant circuit.
19. A refrigerant circuit for a vehicle, comprising: a compressor
configured to compress a refrigerant; an internal heat exchanger in
fluid communication with the compressor to receive the refrigerant
therein, the internal heat exchanger including a high pressure side
part and a low pressure side part, wherein the high pressure side
part is in fluid communication with a condenser/gas cooler and a
heat exchanger/chiller; a first controllable expansion device
configured to decrease a pressure level of the refrigerant, the
first controllable expansion device in fluid communication with the
internal heat exchanger and the condenser/gas cooler, wherein the
first controllable expansion device permits the high pressure side
part of the internal heat exchanger to receive the refrigerant
during a heat pump operation of the refrigerant circuit between a
pressure level at which the refrigerant exits the compressor and a
pressure level at which the refrigerant enters the compressor; and
a second controllable expansion device configured to decrease a
pressure level of the refrigerant, the second controllable
expansion device in fluid communication with the internal heat
exchanger and the heat exchanger/chiller, wherein the second
controllable expansion device permits the high pressure side part
of the internal heat exchanger to receive the refrigerant during
the heat pump operation of the refrigerant circuit between the
pressure level at which the refrigerant exits the compressor and
the pressure level at which the refrigerant enters the
compressor.
20. The refrigerant circuit of claim 19, wherein the second
controllable expansion device and the first controllable expansion
device can be operated at least one of individually, alternatingly,
synchronously, and any combination thereof.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of German Patent
Application No. DE 10 2011 109 506.7 filed Aug. 5, 2011, the entire
disclosure of which is hereby incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The invention involves a refrigerant circuit for a vehicle,
and more particularly a refrigerant circuit for a vehicle
configured to optimize performance of an internal heat exchanger
during a cooling operation and a heat pump operation.
BACKGROUND OF THE INVENTION
[0003] DE 103 09 779 A1 discloses a double-loop air conditioner in
which refrigerant is heated in a heat pump or through a compression
of the refrigerant, and is then released to a condenser in an
interior space module (hereinafter referred to as the heat
register) for heating an inflow of air into an interior space. In
addition, heat can be taken from a refrigerant circuit of a motor
and directed to the refrigerant through a heat transfer device, or
an inflow of air into the interior space may be heated in a
conventional heating device via a heating core through which the
refrigerant flows. In a cooling device, heat is removed from the
inflow of air into the interior by a condenser, which in this
operation works as an evaporator. The heat given off to a cooling
material is thereupon released to the environment through another
condenser.
[0004] DE 101 58 104 B4 discloses an air conditioner that has a
refrigerant circuit in which heat in a heat pump process is taken
from an outside air. The heat is released for heating an interior
space inflow of air under high pressure through a condenser, which
functions in a heating unit as a gas cooler or as a condenser.
[0005] It is known that a refrigerant circuit that is appropriate
for both cooling and heat pump operation has a high and low
pressure area. Such a refrigerant circuit includes at least one
heat source or heat sink, such as a gas cooler or condenser and/or
a glycol heat exchanger, as well as a compressor, an expansion
module, at least a thermal interior space module and a refrigerant
storage area.
[0006] In addition, an internal heat exchanger is provided, which
has a high pressure side part and a low pressure side part, whereby
the high pressure side part of the internal heat exchanger in the
heat pump lies between the expansion module and the gas cooler. The
low pressure side of the internal heat exchanger is arranged on a
suction side of the compressor.
[0007] A disadvantage of the refrigerant circuit is that no heat
exchange with the low pressure side part of the internal heat
exchanger in the heat pump operation can occur without significant
technical effort since the internal heat exchanger in the heat pump
is disposed in the low pressure area of the refrigerant circuit.
The internal heat exchanger is relatively inactive in the heat pump
operation.
[0008] Further, the heat pump contains an excessive amount of the
refrigerant since a filling amount is determined according to the
air conditioner operation. As a result, suctioning of the
refrigerant into the compressor is unavoidable, thereby decreasing
an efficiency of the compressor.
[0009] Accordingly, it would be desirable to produce a refrigerant
circuit for a vehicle configured to optimize performance of an
internal heat exchanger during a cooling operation and a heat pump
operation.
SUMMARY OF THE INVENTION
[0010] In concordance and agreement with the present invention, a
refrigerant circuit for a vehicle configured to optimize
performance of an internal heat exchanger during a cooling
operation and a heat pump operation, has surprisingly been
discovered.
[0011] In one embodiment, a refrigerant circuit for a vehicle,
comprises: a compressor configured to compress a refrigerant; an
internal heat exchanger in fluid communication with the compressor
to receive the refrigerant therein, the internal heat exchanger
including a high pressure side part and a low pressure side part,
wherein the high pressure side part is in fluid communication with
at least one additional heat exchanger; and at least one metering
device configured to control a pressure level of the refrigerant,
the at least one metering device in fluid communication with the
internal heat exchanger, wherein the at least one metering device
permits the high pressure side part of the internal heat exchanger
to receive the refrigerant during a heat pump operation of the
refrigerant circuit between a pressure level at which the
refrigerant exits the compressor and a pressure level at which the
refrigerant enters the compressor.
[0012] In another embodiment, the refrigerant circuit for a
vehicle, comprises; a compressor configured to compress a
refrigerant; an internal heat exchanger in fluid communication with
the compressor to receive the refrigerant therein, the internal
heat exchanger including a high pressure side part and a low
pressure side part, wherein the high pressure side part is in fluid
communication with a condenser/gas cooler and a heat
exchanger/chiller; and at least one controllable expansion device
configured to control a pressure level of the refrigerant, the at
least one controllable expansion device in fluid communication with
the internal heat exchanger, wherein the at least one controllable
expansion device permits the high pressure side part of the
internal heat exchanger to receive the refrigerant during a heat
pump operation of the refrigerant circuit between a pressure level
at which the refrigerant exits the compressor and a pressure level
at which the refrigerant enters the compressor.
[0013] In yet another embodiment, the refrigerant circuit for a
vehicle, comprising: a compressor configured to compress a
refrigerant; an internal heat exchanger in fluid communication with
the compressor to receive the refrigerant therein, the internal
heat exchanger including a high pressure side part and a low
pressure side part, wherein the high pressure side part is in fluid
communication with a condenser/gas cooler and a heat
exchanger/chiller; a first controllable expansion device configured
to decrease a pressure level of the refrigerant, the first
controllable expansion device in fluid communication with the
internal heat exchanger and the condenser/gas cooler, wherein the
first controllable expansion device permits the high pressure side
part of the internal heat exchanger to receive the refrigerant
during a heat pump operation of the refrigerant circuit between a
pressure level at which the refrigerant exits the compressor and a
pressure level at which the refrigerant enters the compressor; and
a second controllable expansion device configured to decrease a
pressure level of the refrigerant, the second controllable
expansion device in fluid communication with the internal heat
exchanger and the heat exchanger/chiller, wherein the second
controllable expansion device permits the high pressure side part
of the internal heat exchanger to receive the refrigerant during
the heat pump operation of the refrigerant circuit between the
pressure level at which the refrigerant exits the compressor and
the pressure level at which the refrigerant enters the
compressor.
[0014] It is an objective of the invention to simplify a
refrigerant circuit to assure an active operation of an internal
heat exchanger during a heat pump operation. A further objective is
to correspondingly store unnecessary refrigerant in various
operating conditions of the cooling and heating operation, and thus
to optimally adjust a level of circulating refrigerant.
[0015] In certain embodiments, active operation of the internal
heat exchanger is assured by relieving a stress of the refrigerant
after the internal heat exchanger. A refrigerant storage area
downstream from the internal heat exchanger in a heat pump is also
supplied with standing refrigerant under high pressure. However,
the storage area is too large based on a density of the
refrigerant. Therefore, a sufficient buildup of pressure on the
high pressure side may not be obtained.
[0016] According to the invention, the refrigerant circuit includes
a metering device through which the high pressure side part of the
internal heat exchanger in the heat pump is driven to a medium
pressure level, which lies between the high and low pressure level
of the refrigerant circuit.
[0017] A loss of pressure of the high pressure side of the inner
heat exchanger to the heat source causes a pressure level of the
stress-relieved two-phase refrigerant to be above that of the
downstream heat source. In extreme cases, an area of the medium
pressure level can be increased or decreased to correspond to the
high pressure or low pressure level.
[0018] Because of the high specific heat of the two-phase
refrigerant and the constant temperature, the internal heat
exchanger can be used actively to superheat the refrigerant in the
heat pump that flows through the low pressure side part of the
internal heat exchanger. Accordingly, operation of the compressor
is assured, and a suctioning of the refrigerant into the compressor
is avoided.
[0019] The configuration and function of the refrigerant circuit
can be employed regardless of the refrigerant used. At times,
differences occur in particular pressure circumstances for low
pressure, medium pressure, and high pressure levels.
[0020] In addition, wiring can be implemented independent of a
drive design of the particular vehicle, be it conventional, hybrid,
electric, etc., and thus independent of a type of the
compressor.
[0021] In an advantageous embodiment, a metering device configured
to drive the high pressure part of the internal heat exchanger to
the medium pressure level is a damper. The damper is disposed
downstream of the high pressure side of the internal heat exchanger
during the heat pump operation, preferably downstream of a
refrigerant storage area.
[0022] The damper is configured to produce a loss of pressure only
in a direction of the flow of the refrigerant in the heat pump,
dependent on a narrowing of a cross-section of the damper. In the
air conditioner, the cross-section is maximized in an opposite
direction of the flow of the refrigerant. A medium pressure level
is adjusted by an expansion valve in the heat pump. The expansion
valve is relieved to low pressure by a decrease of pressure created
by the damper after the refrigerant flows through the internal heat
exchanger.
[0023] Preferentially, the metering device for achieving the medium
pressure level is configured as a conduit adjustment of a conduit
disposed between the heat source or heat sink and the expansion
valve. The refrigerant storage area and high pressure side part of
the internal heat exchanger are also disposed between the heat
source or heat sink and the expansion valve.
[0024] A cross-section of the conduit and a conduit guidance or
bends in the conduit can be calculated for each vehicle, so that no
noticeable loss of pressure occurs during the cooling operation,
while a defined loss of pressure during the heat pump operation can
be obtained for the heating operation.
[0025] In particular, the cross-section of the conduit is smaller
than prior art. Accordingly, material for the conduits, and thus a
cost and a weight can be minimized. A minimized conduit
cross-section also results in a reduction in the amount for filling
and a reduced need for refrigerant over the prior art.
[0026] According to the invention, in addition to the controllable
expansion device, which is disposed in the flow direction in the
heat pump upstream of the high pressure side part of the internal
heat exchanger, at least one additional controllable expansion
device can be employed. The additional controllable expansion
device is disposed in the flow direction downstream of the high
pressure side part of the heat exchanger and downstream of the
refrigerant storage area, yet upstream of the heat source. The
additional controllable expansion device, which initially is at a
medium pressure level, can be decreased to a low pressure
level.
[0027] In another advantageous embodiment, in addition to a
condenser as a heat source or heat sink in the refrigerant circuit,
an additional heat exchanger, in particular an external heat
exchanger, can be provided as an additional heat source or heat
sink for transferring heat between the motor and the refrigerant
circuit. The additional external heat exchanger can be configured
as a water-glycol heat exchanger (i.e. a chiller). The additional
heat exchanger can be located in the refrigerant circuit either
parallel or serial to the condenser. In both configurations, the
conduit to the condenser and the conduit to the additional heat
exchanger branch from the conduit originating from the high
pressure side part of the internal heat exchanger. In an
advantageous embodiment, the two branches can be combined together
via one controllable expansion device. The refrigerant stream flow
to one of the branches can be determined by control of the
expansion device by which switch valves are replaced. Additionally,
the controllable adjustment of the medium pressure level in the
internal heat exchanger and the refrigerant storage area is assured
for both of the branches.
[0028] By disposing the controllable expansion device in the heat
pump downstream of the refrigerant storage area, the pressure level
in the refrigerant storage area--and according to the wiring
variant in the internal heat exchanger as well--can be flexible in
a manner that optimizes the amount of refrigerant available in the
refrigerant circuit.
[0029] Furthermore, the invention involves a method for operating
an air conditioner including a refrigerant circuit as described
hereinabove, whereby at least one additional controllable expansion
device is employed in addition to the controllable expansion device
disposed in the flow direction in the heat pump upstream of the
high pressure side part of the internal heat exchanger. The
additional controllable expansion device is disposed in the flow
direction downstream of the high pressure side part of the heat
exchanger and downstream the refrigerant storage area, yet upstream
of the heat source.
[0030] According to the invention, the expansion devices are
controlled and defined during operation. In particular, in the heat
pump, the expansion devices are controlled to work individually, in
which particular expansion devices work individually, and any other
expansion devices are opened fully. In another application, all the
expansion devices can be operated in combination with each other.
In such case, the expansion devices are opened in interaction with
one another in order to obtain a desired pressure level.
Preferentially, the expansion devices can be operated alternately,
as needed in combination, or individually.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] The above, as well as other objects and advantages of the
invention, will become readily apparent to those skilled in the art
from reading the following detailed description of a preferred
embodiment of the invention when considered in the light of the
accompanying drawings in which:
[0032] FIG. 1 is a schematic flow diagram of a refrigerant circuit
according to an embodiment of the invention, showing a cooling
operation thereof;
[0033] FIG. 1A is a schematic flow diagram of the refrigerant
circuit illustrated in FIG. 1, showing a heat pump operation
thereof;
[0034] FIG. 2 is a schematic flow diagram of a refrigerant circuit
according to another embodiment of the invention, wherein the
refrigerant circuit includes a conduit having an adjustable
cross-section;
[0035] FIG. 3 is a schematic flow diagram of a refrigerant circuit
according to another embodiment of the invention, wherein the
refrigerant circuit includes controllable expansion devices and
serial connection of a plurality of heat exchangers; and
[0036] FIG. 4 is a schematic flow diagram of a refrigerant circuit
according to another embodiment of the invention, wherein the
refrigerant circuit includes controllable expansion devices and
parallel connection of a plurality of heat exchangers.
DETAILED DESCRIPTION of EXEMPLARY EMBODIMENTS OF THE INVENTION
[0037] The following detailed description and appended drawings
describe and illustrate various exemplary embodiments of the
invention. The description and drawings serve to enable one skilled
in the art to make and use the invention, and are not intended to
limit the scope of the invention in any manner. Equivalent
components or components with equivalent effect are shown in the
following examples of embodiments with the same reference list
number.
[0038] FIGS. 1 and IA show a schematic presentation of a
refrigerant circuit 10 of a vehicle air conditioner according to
the present invention. The refrigerant circuit 10 is suitable for
both a cooling operation, illustrated in FIG. 1, and a heat pump
operation, illustrated in FIG. 1A. During the cooling operation
shown in FIG. 1, a refrigerant under high pressure flows out of a
compressor 12 through a valve 14, through a condenser/gas cooler
26, and through a metering device 22. As a non-limiting example,
the valve 14 is a 3-2 way valve and the metering device 22 is a
damper. However, it would be understood to employ two separate
controllable shutoff valves.
[0039] The metering device 22 is configured to decrease pressure
only during the heat pump operation. On the other hand, during the
cooling operation, the metering device 22 produces no or minimal
pressure loss. The refrigerant flows through a refrigerant storage
area 24 and a high pressure side part of an internal heat exchanger
20 at a high pressure level HD. The pressure level of the
refrigerant is decreased from the high pressure level HD to a low
pressure level ND at a main expansion valve 18. A shutoff valve 32
is in an open position, permitting the refrigerant at the low
pressure level ND to flow through the evaporator 34 and then
through a low pressure side part of an interior heat exchange 30.
From the internal heat exchanger 30 the refrigerant flows to the
compressor 12 to be compressed to the high pressure level HD.
Because of a configuration of the metering device 22, no change in
the pressure level of the refrigerant results from flowing through
the metering device 22 during the cooling operation.
[0040] Conversely, during the heat pump operation shown in FIG. 1A,
the refrigerant flows from the compressor 12 through the valve 14,
through a heat register 16 to the main expansion valve 18. The
refrigerant is at the high pressure level HD up to the main
expansion valve 18. At the main expansion valve 18, the pressure
level of the refrigerant is decreased to a medium pressure level
MD. The refrigerant then flows from the main expansion valve 18
through the high pressure side of the internal heat exchanger 20.
Thereafter, the refrigerant flows through the refrigerant storage
area 24 to the metering device 22. The metering device 22 decreases
a pressure level of the refrigerant from the medium pressure level
MD to the low pressure level ND in the flow direction of the heat
pump. At the low pressure level ND, the refrigerant flows through
the condenser/gas cooler 26 operating as an evaporator. A shutoff
valve 28 is in an open position, permitting the refrigerant at the
low pressure level ND to flow to the low pressure side of the
internal heat exchanger 30. The refrigerant flows through the low
pressure side of the internal heat exchanger 30 and into the
compressor 12. At the compressor 12, the refrigerant is once again
compressed to the high pressure level HD.
[0041] According to the invention, during the heat pump operation,
the refrigerant that flows through the high pressure side of the
internal heat exchanger 20 is at the medium level pressure level
MD, producing a potential heat exchange with the low pressure part
of the internal heat exchanger 20. An advantage of the invention is
that the refrigerant flowing through the low pressure part of the
internal heat exchanger 30 is heated or superheated before entry
into the compressor 12. A suction of a fluid refrigerant into the
compressor 12 is militated against by the superheating of the
refrigerant. Accordingly, effective operation of the compressor 12
is maintained.
[0042] FIG. 2 shows the refrigerant circuit 10 of a vehicle air
conditioner according to another embodiment of the invention.
During the heat pump operation, the medium pressure level MD of the
refrigerant is assured by a metering device 36. As a non-limiting
example, the metering device 36 is a conduit located between the
main expansion valve 18 and the gas cooler 26. An adjustment of a
cross-section of the conduit 36 controls a pressure of the
refrigerant. The cross section of the conduit 36 is shown only
schematically in FIG. 2. The cross section of the conduit 36 is
configured in such a manner to produce a loss of pressure during
the heat pump operation, but not during the cooling operation. This
can be achieved on the basis of the different conditions of the
refrigerant during the heat pump operation and the cooling
operation. To ensure the affect, a technical conduit analysis can
be conducted separately for each vehicle, in particular, as a
function of conduit guidance or existing bends.
[0043] In another advantageous embodiment shown in FIG. 3, the
refrigerant circuit 10 includes, in addition to the condenser/gas
cooler 26, at least one chiller 38 for heat exchange with the
refrigerant circuit 10, such as that of a vehicle motor. Additional
heat sources might also be represented by an exhaust system or by
various refrigerant circuits of a partially or fully electric
vehicle.
[0044] In addition to the main expansion valve 18, metering devices
40, 42 are contemplated to guarantee the medium pressure level MD
in the high pressure part of the internal heat exchanger 20. Hence,
the flow of the refrigerant can be guided either through the glycol
heat exchanger/chiller 38, the condenser/gas cooler 26, or a
combination thereof. As a non-limiting example, the metering
devices 40, 42 are additional controllable expansion devices 40,
42. In a pass-through position of the metering devices 40, 42, the
medium pressure level MD during the heat pump operation is
decreased to the low pressure level ND in order to be able to
accept energy in the glycol heat exchanger/chiller 38 and/or the
gas cooler 26. In this manner, the refrigerant circuit shown in
FIG. 3 is advantageous because the refrigerant flowing into the
high pressure side of the internal heat exchanger 20 is at the
medium pressure level MD and can be used for superheating the
refrigerant on the suction side of the compressor 12.
[0045] In addition, the pressure level of the refrigerant in the
refrigerant storage area 24 can be so adjusted by the defined
setting of the controllable main expansion valve 18 and of the
other metering devices 40, 42 that as a result the storage of the
refrigerant is assured at a density that guarantees both efficient
heating and an effective and reliable operation of the compressor
12.
[0046] FIG. 4 shows an embodiment of the refrigerant circuit 10
that, in its function, essentially corresponds to the refrigerant
circuit 10 shown in FIG. 3. As a distinction over FIG. 3, a
connection conduit is employed which connects a flow channel
through the condenser/gas cooler 26 to a flow channel through the
glycol heat exchanger/chiller 38 via a shutoff valve 44 downstream
of the condenser/gas cooler 26 and the glycol heat
exchanger/chiller 38. Accordingly, the condenser/gas cooler 26 and
the glycol heat exchanger/chiller 38 shown in FIG. 4 are connected
and operate in parallel, while the condenser/gas cooler 26 and the
glycol heat exchanger/chiller 38 shown in FIG. 3 are connected and
operate in series.
[0047] From the foregoing description, one ordinarily skilled in
the art can easily ascertain the essential characteristics of this
invention and, without departing from the spirit and scope thereof,
make various changes and modifications to the invention to adapt it
to various usages and conditions.
LIST OF REFERENCE NUMERALS
[0048] 10 Refrigerant circuit [0049] 12 Compressor [0050] 14
Three-two way valve [0051] 16 Heat register [0052] 18 Controllable
main expansion device [0053] 20 Internal heat exchanger (high
pressure) [0054] 22 Damper [0055] 24 Refrigerant storage area
[0056] 26 Condenser/gas cooler [0057] 28 Shutoff valve [0058] 30
Internal heat exchanger (low pressure) [0059] 32 Shutoff valve
[0060] 34 Evaporator [0061] 36 Conduit cross-section [0062] 38
Glycol heat exchanger/chiller [0063] 40 Controllable main expansion
device [0064] 42 Controllable main expansion device [0065] 44
Shutoff valve [0066] ND Low pressure level [0067] MD Medium
pressure level [0068] HD High pressure level
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