U.S. patent application number 12/162685 was filed with the patent office on 2009-01-29 for heat exchanger with cold reservoir.
This patent application is currently assigned to BEHR GMBH & CO. KG. Invention is credited to Boris Kerler, Michael Kohl, Ralf Manski, Thomas Strauss, Christoph Walter.
Application Number | 20090025419 12/162685 |
Document ID | / |
Family ID | 38261601 |
Filed Date | 2009-01-29 |
United States Patent
Application |
20090025419 |
Kind Code |
A1 |
Kerler; Boris ; et
al. |
January 29, 2009 |
HEAT EXCHANGER WITH COLD RESERVOIR
Abstract
The invention relates to a heat exchanger, in particular, an
evaporator (1), in particular for a motor vehicle air-conditioner,
with a number of closely arranged refrigerant tubes and at least
one cold reservoir (4), in which a refrigerant medium is provided.
The evaporator (1) comprises two parallel regions (1' and 1'')
running across the total width, the first region (1') corresponding
to a conventional evaporator in design, the cold reservoir (4)
being arranged in a separate second region (1''), through which at
least a partial flow of refrigerant can flow which also flows
through at least a part of the first region (1') and the first and
the second region are connected to each other by at least one
overflow opening (13).
Inventors: |
Kerler; Boris; (Stuttgart,
DE) ; Kohl; Michael; (Bietigheim, DE) ;
Manski; Ralf; (Stuttgart, DE) ; Strauss; Thomas;
(Notzingen, DE) ; Walter; Christoph; (Stuttgart,
DE) |
Correspondence
Address: |
FOLEY AND LARDNER LLP;SUITE 500
3000 K STREET NW
WASHINGTON
DC
20007
US
|
Assignee: |
BEHR GMBH & CO. KG
|
Family ID: |
38261601 |
Appl. No.: |
12/162685 |
Filed: |
February 6, 2007 |
PCT Filed: |
February 6, 2007 |
PCT NO: |
PCT/EP2007/000996 |
371 Date: |
July 30, 2008 |
Current U.S.
Class: |
62/524 |
Current CPC
Class: |
F28D 2021/0085 20130101;
F28D 1/05391 20130101; F28D 20/02 20130101; Y02E 60/14 20130101;
F28D 1/0408 20130101; F28D 2020/0013 20130101; F25B 39/022
20130101; Y02E 60/145 20130101; F25B 2400/24 20130101 |
Class at
Publication: |
62/524 |
International
Class: |
F25B 39/02 20060101
F25B039/02 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 10, 2006 |
DE |
10 2006 006 444.5 |
Claims
1. A heat exchanger, in particular an evaporator, in particular for
a motor vehicle air conditioning system having a plurality of
mutually adjacent, refrigerant-carrying tubes and having at least
one cold store, in which a cold storage medium is provided, wherein
the evaporator has two mutually parallel regions extending over the
entire width, wherein the first region corresponds in its structure
to a conventional evaporator, the cold store is disposed in an
independent second region, which can be flowed through by at least
a part of the refrigerant flow, and the first and the second region
are connected to each other by at least one overflow opening.
2. The heat exchanger as claimed in claim 1, wherein two overflow
openings are provided.
3. The heat exchanger as claimed in claim 1, wherein in at least
one cold storage element there is disposed at least one
refrigerant-carrying tube.
4. The heat exchanger as claimed in claim 1, wherein the tube which
carries the refrigerant and/or contains the cold storage medium is
a double-walled flat tube, the refrigerant being located in the
central region and the cold storage medium in the outer region.
5. The heat exchanger as claimed in claim 1, wherein the
refrigerant-carrying tubes of the second region end in a reservoir,
which is configured separate from and only by one or more overflow
openings to a reservoir of the first region.
6. The heat exchanger as claimed in claim 1, wherein the tubes or
channels carrying cold storage medium end in a cold storage medium
reservoir, through which the refrigerant-carrying tubes or channels
project, which end in a separate reservoir.
7. The heat exchanger as claimed in claim 1, wherein the first
region has, in the direction of its width adjacent to the second
region, a number of blocks which can be flowed through in different
direction by the refrigerant, and the second region has at least
one block, in particular a number of blocks which can be flowed
through in different direction by the refrigerant, and the number
and/or width of the individual blocks in the latitudinal direction
of the evaporator differs in the first region and in the second
region.
8. The heat exchanger as claimed in claim 7, wherein the first
region has directly adjacent to the second region two to four, in
particular three blocks, and the second region has one to six
blocks, in particular two to four blocks.
9. The heat exchanger as claimed in claim 1, wherein the phase
change temperature of the cold storage medium lies within a range
from 0.degree. C. to 30.degree. C., preferably 1.degree. C. to
20.degree. C., in particular from 2.degree. C. to 15.degree. C., in
particular preferably from 4.degree. C. to 12.degree. C.
10. The heat exchanger as claimed in claim 1, wherein in the cold
store there is disposed at least one inlay.
11. An air conditioning system with cold store, in particular for a
motor vehicle, having a refrigerant circuit, characterized by an
evaporator according to claim 1.
Description
[0001] The invention relates to a heat exchanger, in particular for
a motor vehicle air conditioning system, with cold store according
to the preamble to claim 1.
[0002] It is an aim of the motor vehicle manufacturers to reduce
the fuel consumption of the vehicle. One measure for reducing the
fuel consumption is to cut off the engine when the vehicle is
temporarily stationary, for example when stopping at traffic
lights. This temporary cutoff of the engine is also referred to as
idle-stop operation. In modern low-consumption vehicles, such as,
for example, in the so-called three-liter vehicle, this measure is
already being used. In vehicles boasting the idle-stop operating
mode, the engine is cut off for about 25-30% of the journey time in
inner-city traffic.
[0003] This is a reason why such vehicles are often not equipped
with an air conditioning system, for when the engine is shut down,
nor can a compressor necessary for an air conditioning system be
driven, so that in idle-stop operation an air conditioning system
cannot provide the necessary cold capacity. The problem is also
partially solved by the fact that, when the air conditioning system
is switched on, the engine continues running during a stop,
whereby, however, a higher fuel consumption is obtained.
[0004] In DE 101 56 944 A1 there is disclosed an air conditioning
system for a motor vehicle, having a compressor and an evaporator,
disposed in a refrigerant circuit, for the cooling of air to be
conditioned for the interior, which air conditioning system has a
second evaporator for air cooling purposes which additionally
contains a cold storage medium, the air to be conditioned
optionally being able to be passed through each evaporator
individually or through both evaporators jointly. According to an
alternative embodiment, instead of the second evaporator, the
evaporator is configured such that it has two subregions and in one
of the two subregions contains a cold storage medium, the air to be
conditioned optionally being able to be passed through each
evaporator individually or through both evaporators jointly. The
tubes in which the refrigerant flows through the evaporator can
here be configured as multichannel tubes, one or more of the
channels being filled with the cold storage medium.
[0005] Starting from this prior art, the object of the invention is
to provide an improved heat exchanger. This object is achieved by a
heat exchanger having the features of claim 1. Advantageous
embodiments are the subject of the sub-claims.
[0006] According to the invention, a heat exchanger, in particular
an evaporator for a motor vehicle air conditioning system for the
cooling of air to be conditioned for the interior is provided,
having a plurality of mutually adjacent, refrigerant-carrying tubes
and having at least one cold store, in which a cold storage medium
is provided. The evaporator here has two mutually parallel regions
extending over the entire width, wherein the first region
corresponds in its structure to a conventional evaporator, the cold
store is disposed in an independent second region, which can be
flowed through by at least a part of the refrigerant flow, and the
first and the second region are connected to each other by at least
one overflow opening. Via the overflow opening, at least a partial
flow of refrigerant flows over from one region into the other
region, i.e. refrigerant flows in both regions. Between the tubes
of the first and/or of the second region of the heat exchanger
there are disposed corrugated ribs, or other elements which enlarge
the heat transfer surface. The fact that the first region
substantially corresponds to that of a conventional heat exchanger
means that existing tools can continue to be used, only the tools
for the second region and for the creation of the overflow
opening(s) must be newly procured. The second region--if the first
region is designed in accordance with the previous construction--is
relatively easily adaptable to the existing installation space and
the cooling requirement. Furthermore, only one expansion member is
necessary.
[0007] Because of the modular structure, an evaporator which is
configured in this way can also be referred to as an "add-on"
storage evaporator, i.e. to the, in principle, substantially
conventional basic form of the evaporator is added a
correspondingly configured cooling module.
[0008] Preferably, precisely two overflow openings are provided,
though--in the case of a separate refrigerant feed--just one
overflow opening may also be provided. Similarly, a plurality of
overflow openings are possible, through which refrigerant can flow
over from the first region to the second region and vice versa.
[0009] In at least one cold storage element there is preferably
disposed at least one refrigerant-carrying tube. The cold storage
elements can here be connected to one another, in particular by at
least one reservoir.
[0010] In one arrangement of the refrigerant-carrying tube in the
cold storage element, it can be plugged into the cold storage
element filled with the cold storage medium or else can be
configured directly therein, the cold storage medium preferably
surrounding the refrigerant from all sides and, in particular, a
tube-in-tube arrangement being provided.
[0011] Likewise, the cold storage element can be formed by a tube
of U-shaped cross section, in particular having a plurality of
chambers. In this case, the internal dimensions of the cold storage
element preferably correspond to the external dimensions of the
refrigerant-carrying tube in the corresponding region, so that the
tubes bear full-facedly one against the other. A one-piece
embodiment, for example formed by a correspondingly extruded tube
having at least two channels, is also possible.
[0012] In the case of an arrangement fully within the cold storage
element, the tube which carries the refrigerant and contains the
cold storage medium is preferably configured as a double-walled
flat tube, the refrigerant being located in the central region and
the cold storage medium in the outer region. According to a further
preferred embodiment, the double-walled flat part has webs, which
connect the outer to the inner flat tube. The fact that the cold
store has direct air contact produces very good dynamics in the
heat transfer, so that, where necessary, i.e. in idle-stop
operation, the full cold capacity is immediately available.
[0013] The tube containing the cold storage medium may also not
fully surround the refrigerant-carrying tube. In this case,
preferably, precisely three sides of the refrigerant-carrying tube
are surrounded by the tube containing the cold storage medium. The
tube containing the cold storage medium can here be configured with
a U-shaped cross section and can surround the refrigerant-carrying
tube, preferably a flat tube, partially, i.e. over a part of its
periphery, the greatest part of the refrigerant-carrying tube
preferably being disposed inside the tube containing the cold
storage medium.
[0014] Preferably, the refrigerant-carrying tubes of the second
region end in a reservoir, which is configured separate from and
only by one or more overflow openings to a reservoir of the first
region. This allows the heat exchanger, where appropriate, also to
be retrofitted with a cold store, in particular the first
regions--apart from the overflow openings--can however be
identically configured, as in the case of conventional heat
exchangers, so that the manufacturing costs, as a result of larger
batch sizes and same tools for a large part of the component parts,
are able to be lowered. Furthermore, the two regions can be put
together separately and then connected to each other.
[0015] The tubes or channels carrying cold storage medium
preferably end in a cold storage medium reservoir, through which
the refrigerant-carrying tubes or channels project, which end in a
separate reservoir. This allows the individual cold storage
elements to be jointly filled with the cold storage medium, so that
a simple and rapid filling of the tubes or channels carrying the
cold storage medium is possible. Furthermore, the assembly can be
simplified by the preferably one-piece design of the cold store in
the case of a separate configuration of the refrigerant-carrying
tubes and of the cold storage elements. A compensating space for,
in particular, temperature-induced changes in volume of the
refrigerant can thereby be provided. Furthermore, this allows a
compact design of the second region.
[0016] Preferably, the first region has, in the direction of its
width adjacent to the second region, a number of blocks which can
be flowed through in different direction by the refrigerant, and
the second region has at least one block, in particular a number of
blocks which can be flowed through in different direction by the
refrigerant. Here, the number and/or width of the individual blocks
in the latitudinal direction of the evaporator preferably differs
in the first region and in the second region. The first region
preferably has directly adjacent to the second region two to four,
in particular three blocks, and the second region has one to six
blocks, in particular two to four blocks.
[0017] Preferably, flat tube rows of the first region and of the
second region are mutually aligned, a flat tube of the second
region also being able to be disposed, however, only behind every
nth, in particular every second or third flat tube, of the first
region, so that the air flow resistance is as low as possible,
though the flat tube rows may also be disposed in irregular or
offset arrangement (for example, centrally staggered), or the cold
storage elements with the refrigerant-carrying tubes disposed
therein may be arranged wryly relative to the other flat tubes of
the evaporator. The number and shape of the flat tubes of the
second region can be chosen in accordance with the desired heat
quantity in the case of a vehicle stop.
[0018] The second region of the evaporator is preferably disposed,
viewed in the normal air flow direction, after the first region of
the evaporator, in particular directly following the evaporator,
but an arrangement before the evaporator or somewhat remote from
the evaporator is also possible in a second, in particular smaller
evaporator part. Particularly in the case of a remote arrangement
from the (main) evaporator, the size of the collector with cold
store can be adapted in accordance with the existing installation
space and/or the requirements. It is particularly advantageous that
the existing evaporator does not have to be modified, or only very
slightly, so that a relatively simple integration of the cold store
into existing systems is possible. Existing tools do not have to be
modified (or only very slightly). Only the tools for the cold
storage region of the evaporator which is added on have to be
procured.
[0019] The tubes which are flowed through by the refrigerant are
preferably constituted by welded or folded flat tubes, or flat
tubes which are deep-drawn or extruded from blanks and can be
configured both rounded and square. Oval tubes or round tubes can
also however be used. As materials, in particular aluminum and
aluminum alloys can enter into consideration, but the use of other
suitable, good heat-conducting materials of choice is also
possible.
[0020] The cold store preferably consists of aluminum, in
particular internally and/or externally coated aluminum (by
aluminum also being understood an aluminum alloy), where
appropriate also copper, a copper-zinc alloy, synthetic resin or
plastic. An aluminum reservoir has the advantage that it can be
soldered together with the other parts of the evaporator without
difficulty. Preferably it is in the form of an extruded flat tube
having a plurality of channels, one part of the channels containing
the cold storage medium and the other part of the channels
containing the refrigerant. The design may also, however, be
multipart.
[0021] The latent or storage medium is preferably constituted by a
PCM material (phase change material), which preferably contains or
is formed from congruently melting media, in particular decanol,
tetra-,penta- or hexadecane, Li--ClO.sub.33H.sub.2O, aqueous salt
solutions or organic hydrates. In the storage medium nucleating
agents can also be provided, which accelerate the
crystallization.
[0022] The phase change temperature of the storage medium lies
preferably within a range from 0.degree. C. to 30.degree. C.,
preferably from 1.degree. C. to 20.degree. C., in particular from
2.degree. C. to 15.degree. C., in particular preferably from
4.degree. C. to 12.degree. C.
[0023] Inside the cold storage element--irrespective of whether it
wholly or only partially surrounds the refrigerant-carrying
tube--inlays such as ribbed sheet-metal plates, preferably of
aluminum, though other metals or plastics are also suitable, or
other turbulence inlays such as nonwovens or knitted fabrics, for
example of plastic or metal, or foams, for example metal foams or
plastic foams, can be provided. The inlays serve to improve the
heat transport and to increase the inner surface in order to
accelerate the crystallization of the storage medium.
[0024] The two regions are preferably flowed through in series, so
that only one expansion member is provided for both regions. The
refrigerant inlet is here preferably provided on the collector of
the first region.
[0025] Preferably, the heat exchanger has the following dimensions
(with respect to the measurements, reference is made to FIGS. 8 and
9).
[0026] The total depth T of the heat exchanger is preferably 23 to
200 mm, in particular 35 to 80 mm, particularly preferably 60+/-10
mm.
[0027] The installation depth T' is preferably 20 to 150 mm, in
particular 25 to 90 mm. The installation depths T1 and T2 of the
flat tubes of the evaporator in the region without cold store are
generally mutually corresponding (symmetrical shaping of this
evaporator region).
[0028] The widths b1 and b2 of the flat tubes of the evaporator in
the region without cold store are preferably mutually
corresponding, a flat tube of one row preferably being respectively
aligned with a flat tube of the other row. The widths b1 and b2 are
preferably 0.8 to 4 mm, in particular 1.3 to 3.5 mm.
[0029] The transverse spacing q1 of the first flat tube row is
preferably 4 to 20 mm, particularly preferably 5 to 13 mm. It
preferably corresponds to the transverse spacing of the second flat
tube row of the evaporator.
[0030] The height of the corrugated rib of the first flat tube row
is thus preferably 3 to 18 mm, in particular 4 to 10 mm. It
preferably corresponds to the corrugated rib height of the second
flat tube row of the evaporator.
[0031] The evaporator, in the region of the cold store, has flat
tubes, which contain the cold storage medium in the outer cold
storage medium channels, having widths b3 from preferably 2.0 to
10.0 mm, in particular from 3.0 to 8.0 mm. The width b4 of the flat
tubes disposed therein, in whose refrigerant channels the
refrigerant flows, is preferably 0.6 to 2.5 mm, in particular 0.9
to 1.5 mm.
[0032] The installation depth T3 of the flat tubes of the
evaporator in the region with cold store is preferably 5 to 70 mm,
particularly preferably 10 to 30 mm.
[0033] The transverse spacing q3 of the flat tubes of the
evaporator in the region with cold store is preferably a multiple
of q1, in order to keep the pressure decrease of the
through-flowing air low, but may also correspond to q1.
Particularly preferred values are two and three.
[0034] The height H1 of the cold storage medium reservoir is
preferably 3 to 25 mm, in particular 3 to 15 mm, but is preferably
as small as possible in order to save installation space and keep
the cross section through which air can flow as large as
possible.
[0035] The invention is explained in detail below with reference to
an illustrative embodiment with variants, partially with reference
to the drawing, wherein:
[0036] FIG. 1 shows a perspective view of a heat exchanger with
collector according to the first illustrative embodiment,
[0037] FIG. 2 shows a side view of the heat exchanger of FIG.
1,
[0038] FIG. 3 shows a selective perspective view of the heat
exchanger of FIG. 1, with removed collecting box and collecting
tube,
[0039] FIG. 4 shows a further perspective view of a region of the
heat exchanger of FIG. 1, with laterally opened reservoir and
collecting tube,
[0040] FIG. 5 shows a sectioned side view of the heat exchanger of
FIG. 1,
[0041] FIG. 6 shows a detailed view of an overflow opening,
[0042] FIG. 7 shows a sectioned detailed view of the heat exchanger
of FIG. 1 in the region of the cold store,
[0043] FIG. 8 shows a section transversely through the heat
exchanger of FIG. 1,
[0044] FIG. 9 shows a section through the lower region of the heat
exchanger of FIG. 1,
[0045] FIG. 10 shows a perspective view of the heat exchanger of
FIG. 1, with schematic representation of the refrigerant flow
path,
[0046] FIG. 11 shows a schematic sectional representation of the
heat exchanger of FIG. 1, in illustration of the refrigerant flow
path,
[0047] FIG. 12 shows a schematic side view of the heat exchanger
with cold store of FIG. 1, in illustration of the refrigerant flow
path,
[0048] FIGS. 13a, b show schematic representations of the
refrigerant flow path according to a first variant,
[0049] FIGS. 14a, b show schematic representations of the
refrigerant flow path according to a second variant,
[0050] FIGS. 15a, b show schematic representations of the
refrigerant flow path according to a third variant,
[0051] FIGS. 16a, b show schematic representations of the
refrigerant flow path according to a fourth variant,
[0052] FIGS. 17a, b show schematic representations of the
refrigerant flow path according to a fifth variant, and
[0053] FIGS. 18a, b show schematic representations of the
refrigerant flow path according to a sixth variant.
[0054] A motor vehicle air conditioning system for controlling the
temperature of the motor vehicle interior having a refrigerant
circuit (in the present case R134a, though CO.sub.2 or another
refrigerant, for example, may also be used) of which only the
evaporator 1, with injection tube 2 and suction tube 3, is
represented, has a cold store 4 in order to provide a sufficient
cooling capacity at least for a short while even when the engine is
stopped, which cold store consists of a plurality of cold storage
elements 5, in the present case twenty-two, which are filled with a
cold storage medium. The cold storage elements 5 are formed by
regions of specially shaped, aluminum flat tubes 6, discussed in
greater detail at a later point. Serving in the present case as the
cold storage medium is decanol. Alternatively, tetra-,penta- or
hexadecane, for example, are also suitable.
[0055] The normal air flow direction is indicated in FIGS. 1 and 2
by arrows. The evaporator 1 has in the larger part located on the
leading edge a region 1' with structure corresponding to that of a
conventional evaporator, having two rows of flat tubes 7 and
corrugated ribs 8 disposed therebetween. The flat tubes 7 end
respectively in a reservoir 9. As can be seen from FIGS. 1 and 2,
the refrigerant enters on the narrow side of the upper reservoir 9
on the trailing edge into the evaporator 1 and leaves it on the
same narrow side in the leading edge region of the reservoir 9.
[0056] The other region of the evaporator 1, namely the cold
storage region 1'', which, as a matter of principle, is configured
separate as an independent region of the evaporator 1 and in which
the cold storage elements 5 are provided, is formed by the smaller,
trailing edge part of the evaporator 1.
[0057] As can be seen, in particular, from FIG. 8, the cold store
flat tubes 6 in the cold storage region 1'' and the conventional
flat tubes 7 in the region 1' are arranged such that, in the case
of the first, third, fifth, etc. flat tube 7, a cold store flat
tube 6 is respectively arranged flushly in alignment with the same
in the air flow direction.
[0058] Since the interspaces between the cold store flat tubes 6,
which in the present case are configured in the air flow direction
narrower, but transversely thereto wider than the flat tubes 7, are
because of this arrangement relatively wide, the flow resistance
for the air flowing through the evaporator 1 is virtually
negligible in comparison to the flow resistance of the first region
1' of the evaporator 1 and can be substantially disregarded for the
design of the evaporator 1 with regard to the air through-flow, so
that, relative to a basic variant of the evaporator without the
cold storage region 1'', no or only minor recalculations have to be
made with regard to the air flow. Alternatively, the flat tubes 6
and 7 can be arranged in any other chosen way, for example in
alignment or staggered.
[0059] The cold store flat tubes 6 have a double-walled structure
having a plurality of refrigerant channels 6' and cold storage
medium channels 6'', the refrigerant channels 6' being arranged on
the inside (see FIG. 8). The cold store flat tubes 6 are here
arranged such that the cold storage medium channels 6'' serving as
cold storage elements 5 respectively end in one of two cold storage
medium reservoirs 10, so that the cold storage element 5 has only a
single cavity, which--apart from a compensating space--is fully
filled with the cold storage medium. The filling is realized in a
single operation via an opening in the cold storage medium
reservoir 10. After the filling, the opening is securely closed, so
that unauthorized opening is reliably prevented.
[0060] According to a variant not represented in the drawing,
inside the continuous cavity elements are provided, such as, in the
present case, a synthetic non-woven, which serve to improve the
heat transport and to increase the inner surface so as to
accelerate the crystallization of the latent medium.
[0061] The refrigerant channels 6' project with their ends
respectively through the corresponding cold storage medium
reservoirs 10 and end respectively in a reservoir 12 configured
separate from the reservoir 9, in the present case in the form of a
tube, which reservoirs are hereinafter referred to as collecting
tubes.
[0062] Each of the collecting tubes is connected by a respective
slot-like overflow opening (not represented) to a slot-like
overflow opening 13 of the reservoirs 9 disposed at a corresponding
location (see FIG. 5).
[0063] The evaporator 1 is flowed through in its conventional
region 1' in such a way that the refrigerant flow is deflected
twice in the evaporator width, before being deflected depthwise
counter to the air flow direction. In the leading edge region it is
likewise deflected twice widthwise. The evaporator in question thus
has six blocks B1 to B6, respectively three blocks being provided
in the latitudinal direction of the evaporator 1 (i.e. in the row
which is first flowed through, the blocks B1 to B3, and in the row
which is last flowed through, the blocks B4 to B6) and the
individual blocks B1 to B6 of the two block rows are flowed through
in the cross-counterflow operation. This refrigerant flow path is
represented in FIG. 10 by arrows shown with solid line.
[0064] Via the overflow opening 13 in the reservoir 9, shortly
after the entry of the injection tube 2 into the reservoir 9 in the
first block B1, a part of the refrigerant is branched off from the
refrigerant flow, which refrigerant part makes its way via the
overflow opening into the collecting tube and is distributed via
the collecting tube over the refrigerant channels 6' of the flat
tubes 6, which in the present case are flowed through in one
direction, i.e. over the entire width of the evaporator 1 in the
cold storage region 1'' only one storage element block is present.
The branched-off part of the refrigerant is fed via the second
overflow opening provided on the second collecting tube, and the
corresponding second overflow opening 13 on the other reservoir 9,
back to the main refrigerant flow, which in this region of the
block B3 is deflected depthwise to the block B4. The refrigerant
flow path of the partial flow is represented in FIG. 10 by arrows
shown with dashed line.
[0065] Instead of the previously described structure, the
reservoirs can be constructed differently, in particular in panel
construction.
[0066] In the other figures, different variants of the refrigerant
conductance through the cold storage region 1'' of the evaporator 1
is represented, which are designed to ensure that the cold storage
medium in all cold storage medium channels 6'' passes as evenly as
possible through its phase change. For this it is necessary to
ensure that the branched-off partial flow of the refrigerant is
distributed as evenly as possible over the flat tubes 6 with their
refrigerant channels 6'.
[0067] FIGS. 13a and 13b show a circuitry variant having 3-block
circuitry in the storage element. The refrigerant from each of the
first three blocks B1 to B3 of the conventional region 1' of the
evaporator 1 is here distributed into the associated storage
element block (i.e. there are three storage element blocks) and
recirculated. As a result of the reduced number of
parallel-connected flat tubes per storage element block, a better
refrigerant distribution than the previously described illustrative
embodiment is obtained.
[0068] According to one modification of this variant (not
represented in the drawing), more than just one outlet and inlet
opening per block of the conventional region of the evaporator are
provided, so that, for example, six storage element blocks are
provided.
[0069] According to the second variant represented in FIGS. 14a and
14b, the refrigerant flow is guided in the storage element in
accordance with that in the serial evaporator (i.e. twofold
deflection widthwise). In this circuitry, in the event of a one-off
overflow from the conventional region 1' of the evaporator 1, only
one-third of the flat tubes of the storage element is parallelly
subjected to refrigerant. Other circuitries are likewise possible
in the cold storage region 1'', for example five storage element
blocks may be provided.
[0070] FIGS. 15a and 15b show a direct refrigerant inlet into the
refrigerant storage region 1'' instead of into the conventional
region 1' of the evaporator 1. With this variant, a preferred
supply to the storage element block can be ensured should too
little refrigerant be able to be drawn off from the conventional
region 1' of the evaporator 1 through the passage openings.
[0071] In FIGS. 16a and 16b, a split refrigerant inlet for the
conventional region 1' of the evaporator 1 and the cold storage
region 1'' is provided as a fourth variant, i.e. the branching-off
of the partial flow for the cold storage region 1'' is realized
still prior to the entry of the refrigerant into the evaporator 1
in the region of the injection tube. In this case, the refrigerant
distribution over the two inlet openings can be optimized, where
appropriate, via the injection tube diameter and the pressure loss
in the conventional region 1' of the evaporator 1 and in the cold
storage region 1''.
[0072] FIGS. 17a and 17b show a circuitry variant having a serial
connection of the cold storage region 1'' and, downstream, of the
conventional region 1' of the evaporator 1. In this variant, the
cold storage medium in the cold storage region 1'' is first frozen
by means of the refrigerant flow (in the present case, the entry is
made from below), before the refrigerant then in the normal flow
guidance passes through the conventional region 1' of the
evaporator 1. Since the whole of the refrigerant flow is conducted
fully through the cold storage region 1'', this variant freezes the
cold storage medium fastest.
[0073] In FIGS. 18a and 18b, a further circuitry variant is
represented, according to which, once again, a partial flow is
branched off in the first block B1. In the present case, the cold
storage region 1'' here has two blocks, which are flowed through in
different directions. The refrigerant from the cold storage region
1'' here enters into the reservoir of the third block B3 and flows
jointly through the same, i.e. the third block B3 is flowed through
by the whole of the refrigerant, while the first two blocks B1 and
B2 are only flowed through by a (larger) refrigerant partial flow.
According to the represented variant, the two blocks of the cold
storage region 1'' have a different width, the block which is first
flowed through being narrower than the block which is subsequently
flowed through.
[0074] The circuitry variants allow improved dynamics of the
loading and unloading operation to be optimized and the outlet
temperature profile of the evaporator when the vehicle is stopped
to be homogenized.
[0075] All variants are independent of the refrigerant (R134a,
R744), of the collector design (curved collector, panel
construction) and block circuitry of the serial evaporator (for
example, 2 or 4-block circuitry).
* * * * *