WO2019180026A1

WO2019180026A1 - Heat exchanger with phase-change vessel(s) comprising one or a plurality of filling units

Info

Publication number: WO2019180026A1
Application number: PCT/EP2019/056851
Authority: WO
Inventors: Aurélie Bellenfant; Lionel ROBILLON; Frédéric TISON; Franck ROUSSEL
Original assignee: Valeo Systemes Thermiques
Priority date: 2018-03-21
Filing date: 2019-03-19
Publication date: 2019-09-26
Also published as: FR3079290B1; FR3079290A1; CN112166291A; EP3752783A1

Abstract

The present invention relates to a method for production of a heat exchanger (1) comprising at least one phase-change material vessel (12), the said vessel (12) being delimited by at least one first vessel plate (120) through which there passes at least one orifice (1201) for introduction of phase-change material, and an opposite surface, the said vessel (12) comprising a filling unit (14) comprising a first lateral wall (14A) through which there passes at least one filling orifice (1421) which co-operates with the said at least one orifice (1201) for introduction of the said first vessel plate (120), and a second, opposite lateral wall (14B), which delimits a filling chamber together with the first lateral wall (14A), the said filling unit (8) comprising a part (141, 142) which projects relative to a face (1A) of the heat-exchange bundle, a filling opening (1410) passing through the said first or second lateral wall (14A, 14B) of the said projecting part of the said filling unit (8), the said method comprising: a step (194) of filling of the phase-change material vessel (12); a step (195) of closure, at the said projecting part (141, 142), of the said filling chamber; a step (197) of cutting of the first end portion (141) of the said projecting part.

Description

HEAT EXCHANGER WITH PHASE-CHANGE VESSEL(S) COMPRISING ONE OR A PLURALITY OF FILLING UNITS

1. Field of the invention

The field of the invention is that of heat exchangers, of the evaporator type in particular, for motor vehicles.

More specifically, the invention relates to evaporators which use a phase-change material.

2. Prior art

In motor vehicles, it is known to use an air conditioning device which makes it possible to regulate the temperature of the passenger space of the vehicle.

More specifically, these air-conditioning devices use a heat exchanger, in particular an evaporator, such as the one represented in figure 1.

An evaporator 1 of this type comprises a heat-exchange bundle formed by a stack of tubes 10 and interposed units 11, which are placed between two consecutive tubes 10, and permit an exchange of heat between a flow of air passing through the bundle (and more specifically through the interposed units), and a coolant (such as a coolant liquid) circulating in the tubes 10.

For vehicles which are provided with a system for automatic stopping of the engine during short stoppages of the vehicle in particular, a function has been developed which makes it possible, when the vehicle engine is at a standstill and is no longer driving the compressor for circulation of the coolant, to maintain the cooling of the passenger space of the vehicle, thus improving the comfort of the passengers of the motor vehicle.

For this purpose, the evaporator 1 uses one or a plurality of phase-change material vessels 12 which can store cold when the engine of the motor vehicle is running, in order then to return the cold to the air passing through the evaporator 1 such as to cool it, for a limited period, when the vehicle engine is at a standstill.

An evaporator 1 of this type, illustrated partially in figure 2, comprises at least one vessel plate 120, which, after being brazed with an outer face of a tube 10 of the heat- exchange bundle, forms a vessel 12 filled with phase-change material.

It will be noted that, conventionally, the tube 10 is obtained by brazing two tube plates 101, 102, between which an internal interposed unit 103 is disposed (figure 2). The phase-change material vessel 12 is thus in thermal contact with an outer face of the tube 10, the vessel being delimited by the vessel plate 120 and an opposite surface corresponding to an outer face of the tube 10.

Each phase-change material vessel 12 comprises a filling tube, which makes it possible to inject a phase-change material inside the vessel 12.

In general, the filling tube extends from a face of the heat-exchange bundle, projecting by a length of between 10 and 20 mm depending on the cases.

This extension of the filling tube is restrictive for the integration of the evaporator 1 in a housing for heating, ventilation and air conditioning (known as HVAC) of a motor vehicle.

After filling of the phase-change material vessel, the circular filling opening of the filling tube is closed either by crushing, and optionally bending of the crushed part, or by means of a stopper or a ball.

However, in practice, it is difficult to ensure the sealing of the circular opening of the filling tube once it has been closed.

Furthermore, none of the solutions according to the prior art makes it possible to guarantee the sealing of the closure of the phase-change material vessel after filling and closure of the filling tube.

3. Objectives of the invention

The objective of the invention is in particular to provide an efficient solution to at least some of these different problems.

In particular, according to at least one embodiment, an objective of the invention is to provide a technique which makes it possible to optimise the production of a heat exchanger with a phase-change material vessel.

According to at least one embodiment, the objective of the invention is in particular to provide a technique of this type which makes it possible to simplify the closure of a phase-change material vessel of a heat exchanger of this type, and to simplify, and reduce the cost of, production of a heat exchanger of this type.

According to at least one embodiment, another objective of the invention is to provide a technique of this type which makes it possible to improve the sealing of a closure of a phase-change material vessel. 4. Presentation of the invention

For this purpose, the invention proposes a method for production of a heat exchanger comprising a heat-exchange bundle delimiting a coolant circulation circuit, the said heat-exchange bundle comprising at least one tube for circulation of the said coolant, the heat exchanger comprising at least one phase-change material vessel which is in thermal contact with an outer face of the said at least one tube, the said vessel being delimited by at least one first vessel plate through which there passes at least one orifice for introduction of phase-change material, and an opposite surface, the said vessel comprising a filling unit comprising a first lateral wall through which there passes at least one filling orifice which co-operates with the said at least one orifice for introduction of the said first vessel plate, and a second, opposite lateral wall, which delimits a filling chamber together with the first lateral wall, the said filling unit comprising a part which projects relative to a face of the heat-exchange bundle, a filling opening passing through the said first or second lateral wall of the said projecting part of the said filling unit.

According to the invention, the said method comprises:

a step of filling of the phase-change material vessel via the filling opening, the filling chamber, the said at least one filling orifice, and the said at least one introduction orifice;

a step of closure, at the said projecting part, of the said filling chamber;

a step of cutting of the first portion, such that, once the first portion has been cut, only the second portion and the closure area project relative to the said face of the heat-exchange bundle.

The principle of the invention thus consists of simplifying the closure of one or a plurality of phase-change material vessels of a heat exchanger, and of reducing the projecting part of the filling unit of each of the vessels, once the closure has taken place.

According to a possible characteristic, before the cutting step, the method comprises a step of checking the sealing of the closure of the filling chamber.

This guarantees the sealing of the closure of the phase-change material vessel(s). According to a possible characteristic, the step of checking the sealing comprises a step of pressurisation or depressurisation of the part of the filling chamber situated in the first portion, via the filling opening.

According to a possible characteristic, the step of closure of the said filling chamber is carried out by welding the inner faces of the first and second lateral walls.

According to a possible characteristic, the welding is welding by ultrasound.

This makes it possible to simplify the production of the exchanger.

According to a possible characteristic, the location of the closure area is selected such that, once the said cutting step has been carried out, the projecting part comprising the second portion and the closure area extends over a maximum length of 10 mm.

This facilitates the integration of the heat exchanger in an HVAC housing.

The invention also relates to a heat exchanger obtained by means of the production method as previously described.

According to a possible characteristic, the filling unit has a flattened form, and extends substantially parallel to the plane of the said first vessel plate.

According to a possible characteristic, the projecting part comprising the second portion and the closure area extends over a maximum length of 10 mm.

According to a possible characteristic, the said phase-change material vessel is delimited by the first vessel plate coupled to the said at least one tube of the said heat- exchange bundle, the opposite surface being formed by the outer face of the said at least one first tube.

According to a possible characteristic, the said phase-change material vessel is delimited by the said first vessel plate and a second vessel plate coupled to the said first vessel plate, the opposite surface being formed by the said second vessel plate.

5. List of the figures

Other characteristics and advantages of the invention will become apparent from reading the following description of particular embodiments, provided simply by way of non-limiting illustration, and from the appended drawings, in which:

figure 1 illustrates a partial view in perspective of a heat exchanger according to the prior art;

figure 2 is a view in transverse cross-section of a tube associated with a phase- change material vessel and with an external interposed unit of the heat exchanger in figure 1;

figure 3 illustrates a view in perspective of a heat exchanger according to the invention;

figure 4 illustrates a detailed view in perspective of the connection between the filling unit and the vessel plate of a phase-change material vessel of the heat exchanger in figure 3;

figures 5 and 6 illustrate detailed views of the filling unit and of the vessel plate, after obtaining the closure area, and after cutting of the end portion of the filling unit.

6. Description of particular embodiments

6.1. Structure of the heat exchanger

An evaporator according to the invention is presented in relation with figures 3 to

6.

The embodiment described hereinafter is an evaporator designed for heat exchange between a flow of air and a coolant fluid, in particular for an air conditioning device for the passenger space of a motor vehicle.

It will be appreciated that the invention also covers a condenser, a radiator, or any other heat exchanger, irrespective of the fluid which passes through it.

The evaporator 1 according to the invention conventionally comprises a heat- exchange bundle formed by a parallel stack of tubes and external interposed units according to a longitudinal direction of stacking.

The interposed units, which do or do not have shutters, are placed between two consecutive tubes, and make it possible to increase the heat-exchange surface between the flow of air passing through the bundle and the coolant (such as a coolant liquid) circulating in the tubes.

One or a plurality of interposed units are each substituted by a phase-change material vessel 12, which can store cold when the engine of the motor vehicle is running, in order then to restore the cold, for a limited period, to the air passing through the evaporator when the engine of the vehicle is at a standstill.

A phase-change material vessel 12 of this type, formed by at least one vessel plate 120, will be described in greater detail hereinafter.

The evaporator 1 illustrated in figure 3 comprises 10 phase-change material vessels, the filling units 14 of each of these vessels being aligned on an outer face 1A of the heat-exchange bundle.

In other words, the filling with phase-change material is carried out by means of the filling unit 14 which is specific to each phase-change material vessel.

Figure 4 illustrates a partial view in transparency of the evaporator 1 in figure 3.

In this figure 4, the illustrated part of the bundle of the evaporator 4 comprises: a plate 10A of a tube 10 which is designed for the circulation of a coolant;

a vessel plate 120 which is disposed between two tubes 10, and is coupled to the plate 10A in a sealed manner, such as to form a vessel 12 for storage of a phase- change material; and

a unit 14 for filling the vessel 12 with a phase-change material.

In a known manner, the tube 10 on which a vessel plate 120 is assembled comprises two plates 10A, which are stamped and brazed to one another, and between which an internal interposed unit with the form of an undulating metal plate can be disposed.

More specifically, the plates 10A are stamped and assembled to one another in a sealed manner such as, after assembly, to form two adjacent ducts 513, 514 inside which a coolant circulates, which in this case is a coolant fluid.

Although this is not illustrated in figure 4, since a partial view of the evaporator 1 is involved, the vessel plate 120 is coupled to another tube 10.

In this embodiment, the vessel 12 is formed by a first vessel plate 120 and an opposite surface, which in this case is constituted by an outer face of a tube 10 (in this case the outer face of the plate 10A).

Thus, the phase-change material which is stored in the vessel 12 is in direct contact with the outer face of the tube 10, which facilitates and improves the heat exchanges between the coolant circulating in the tube 10 and the phase-change material stored in the vessel 12.

As illustrated in figures 5 and 6, the inner face of the vessel plate 120 has a plurality of bosses which are distributed on the assembly of the vessel plate 120.

The bosses of the vessel plate 120 coupled to a first tube 10 are tangent to, or flush with, the outer face of a second adjacent tube 10. Air passages are thus delimited outside the phase-change material vessel 12, so that a flow of air can circulate between the vessel plate 120 and the outer face of the second, adjacent tube 10 of the heat-exchange bundle of the evaporator 1. This makes it possible to optimise the heat exchanges between the evaporator 1 and the air which passes through it.

The vessel 12 comprises a flattened unit (or pipette) 14 for filling, which is in the form of a flat tube.

This filling unit 14 is obtained by sealed assembly (preferably by brazing) of two half shells which are stamped and disposed opposite one another, defining a filling chamber.

This filling unit 14 comprises a first lateral wall 14A which is designed to be applied against the vessel plate 120, and a second lateral wall 14B.

At least one, and in this case two, filling orifice(s) 1421 pass(es) through the lateral wall 14A.

At least one, and in this case two, introduction orifice(s) 1201 pass(es) through the vessel plate 120.

When the evaporator is assembled, part of the lateral wall 14A of the filling unit 14 is disposed against the outer face of the vessel plate 120.

The filling orifice(s) 1421 of the filling unit 14 then communicate(s) with the introduction orifice(s) 1201 of the vessel plate 120, the number of filling orifices being equal to the number of introduction orifices.

The filling unit 14 with a flattened form extends substantially parallel to the respective planes of the vessel plate 120 and the tube 10.

Part of the filling unit 14 projects from the periphery of the vessel plate 120, relative to the outer face 1A of the heat-exchange bundle. A filling opening 1410 passes through the lateral wall 14A of this projecting part at one end.

The dimensions of the filling unit 14 are selected such that:

when the lateral wall 14A of the filling unit 14 is applied against the vessel plate

120, the filling orifice(s) 1421 communicate(s) with the introduction orifice(s) 1201; and

after brazing of the assembly, the join between the filling unit 14 and the vessel plate 120 is sealed.

It will be noted that the vessel plate 120 comprises a recessed allocated area for accommodation of part of the filling unit 14, such that, when the filling unit 14 is rendered integral with the vessel plate 120, its lateral wall 14B which faces towards the outside of the vessel plate 120 is substantially flush with the outer wall of the latter.

The tube plates 10, the vessel plates 120, the external interposed units and the filling units 14 are made of metal, for example aluminium alloy or the like.

According to a variant, the phase-change material vessel 12 is not formed by a first vessel plate 120 and an opposite surface constituted by an outer face of a tube 10.

In this variant, the vessel 12 is formed by a first vessel plate 120 and an opposite surface, which in this case is constituted by a second vessel plate 120. In this case, the first vessel plate 120 is in contact with a first tube 10, whereas the second vessel plate 120 is in contact with a second tube 10.

The first and second vessel plates are substantially identical, whilst preferably being symmetrical relative to their joining plane. However, the second vessel plate is not rendered integral with a filling unit, and consequently does not comprise an introduction orifice.

According to a variant, it is the lateral wall 14B of the projecting part which has a filling opening 1410 passing through it.

6.2. Production method

It will be appreciated that the production of an evaporator according to the invention comprises a prior step 190 (figure 7) of receipt of all of the elements which constitute it, in particular tube plates 10, internal interposed units, external interposed units 11, first, and if applicable second vessel plates 120, and filling units 14.

The obtaining of these elements is conventional, and is not described in greater detail here.

A filling unit 14 is preassembled on each vessel plate 120 (step 191), such that the first lateral wall 14A of the filling tube 14 is supported against the first vessel plate 120, and the filling orifice(s) 1421 of the filling unit 14 are put into communication with the introduction orifice(s) 1201 of the first vessel plate 120.

The first part of the filling unit 14 is then in the allocated area of the vessel plate 120, and the second part projects from the periphery of the vessel plate 120 (figure 4).

Preassembly of the assembly of the evaporator 1 then takes place (step 192).

This preassembly consists of stacking a plurality of tubes 10 against one another, each tube 10 being constituted by the stacking of two plates 10A, if applicable with interposition of an internal interposed unit. Some of the spaces between consecutive tubes 10 are filled with an external interposed unit 11 or with a first vessel plate 120, or, if applicable, with a first and a second vessel plate 120 coupled to one another.

This assembly is kept preassembled by means of tooling provided for this purpose, which makes it possible to keep the different components of the evaporator 1 slightly compressed against one another.

This preassembled assembly is then introduced into an oven inside which a brazing step 193 is implemented.

The filling unit 14 is optionally kept integral with the corresponding vessel plate 120 by crimping.

When this brazing is completed, the different components of the evaporator 1, including the filling units 14 and the first vessel plates 120, are rendered integral with one another in a sealed manner, and the evaporator 1 is extracted from the oven.

The brazing of the filling unit 14 on the corresponding vessel plate 120 makes it possible to ensure a sealed connection of the filling unit 14 on the vessel plate 120, and more specifically of the filling orifices 1421 with the introduction orifices 1201.

The method then comprises a step 194 of filling of the vessel(s) 12 with phase- change material.

This step consists of injecting a phase-change material, for example by means of vacuum filling, inside each vessel 12 via the corresponding filling unit 14.

This material flows into each filling unit 14 from its filling opening 1410, and flows into the filling chamber, then through the filling and introduction orifices, until it spreads into the vessels 12.

Each vessel 12 is then closed (step 195) by implementation of a closure area 15 at the projecting part of the filling unit 14 (figure 5).

In other words, the filling chamber of the filling unit 14 is closed by means of a closure area 15.

For this purpose, the inner faces of the walls 14A and 14B are rendered integral along their entire height by welding, in particular by ultrasound welding.

Any other known technique for rendering integral can be implemented. Contrary to the cylindrical sealing solutions according to the prior art, the invention proposes a flat sealing solution which decreases greatly the risks of leakage of phase-change material.

The closure area 15 thus delimits:

- a first end portion 141 of the said projecting part comprising the filling opening 1410; and

- a second portion 142 of the said projecting part situated between the closure area 15 and the face 1A of the heat-exchange bundle.

The method then comprises a test step 196, which consists of checking the sealing of the closure of the filling chamber of the evaporator 1.

The step 197 of checking the sealing comprises a step of pressurisation or depressurisation of the part of the filling chamber which is situated in the first end portion 141 via the filling opening 1410.

The sealing of the closure of the phase-change material vessel 12 is guaranteed after filling and closure of the filling unit 14.

Finally, the method comprises a step 197 of cutting (figure 6) of the first portion 141, such that, once the first end portion 141 has been cut, only the second portion 142 and the closure area 15 project relative to the said face 1A of the heat- exchange bundle.

Advantageously, the location of the closure area 15 is selected such that, once the said cutting step 197 has been carried out, the projecting part comprising the second portion 142 and the closure area 15 extends over a maximum length of 10 mm.

This slight extension of the filling tube facilitates the integration of the evaporator 1 in an HVAC housing.

It will be noted that the form of the filling opening 1410 can be circular, square or triangular, for example.

Claims

1. Method for production of a heat exchanger (1) comprising a heat-exchange bundle delimiting a coolant circulation circuit, the said heat-exchange bundle comprising at least one tube (10) for circulation of the said coolant, the heat exchanger (1) comprising at least one phase-change material vessel (12) which is in thermal contact with an outer face of the said at least one tube (10), the said vessel (12) being delimited by at least one first vessel plate (120) through which there passes at least one orifice (1201) for introduction of phase-change material, and an opposite surface, the said vessel (12) comprising a filling unit (14) comprising a first lateral wall (14A) through which there passes at least one filling orifice (1421) which co-operates with the said at least one orifice (1201) for introduction of the said first vessel plate (120), and a second, opposite lateral wall (14B), which delimits a filling chamber together with the first lateral wall (14A), the said filling unit (8) comprising a part (141, 142) which projects relative to a face (1A) of the heat-exchange bundle, a filling opening (1410) passing through the said first or second lateral wall (14A, 14B) of the said projecting part of the said filling unit (8),

the said method being characterised in that it comprises:

a step (194) of filling of the phase-change material vessel (12) via the filling opening (1410), the filling chamber, the said at least one filling orifice (1421), and the said at least one introduction orifice (1201);

a step (195) of closure, at the said projecting part (141, 142), of the said filling chamber;

a step (197) of cutting of the first portion (141), such that, once the first portion (141) has been cut, only the second portion (142) and the closure area (15) project relative to the said face (1A) of the heat-exchange bundle.

2. Method according to claim 1, characterised in that, before the step (197) of cutting, it comprises a step (196) of checking the sealing of the closure of the filling chamber.

3. Method according to claim 2, characterised in that the step (196) of checking the sealing comprises a step of pressurisation or depressurisation of the part of the filling chamber situated in the first portion (141), via the filling opening (1410).

4. Method according to any one of claims 1 to 3, characterised in that the step (195) of closure of the said filling chamber is carried out by welding the inner faces of the first and second lateral walls (83, 85).

5. Method according to claim 4, characterised in that the welding is welding by ultrasound.

6. Method according to any one of claims 1 to 5, characterised in that the location of the closure area (15) is selected such that, once the said cutting step has been carried out, the projecting part comprising the second portion (142) and the closure area (15) extends over a maximum length of 10 mm.

7. Heat exchanger (1) obtained by means of the production method according to one of claims 1 to 6.

8. Heat exchanger (1) according to claim 7, wherein the filling unit (14) has a flattened form, and extends substantially parallel to the plane of the said first vessel plate (120).

9. Heat exchanger (1) according to claim 7 or 8, wherein the projecting part comprising the second portion (142) and the closure area (15) extends over a maximum length of 10 mm.

10. Heat exchanger (1) according to one of claims 7 to 9, wherein the said phase- change material vessel (12) is delimited by the first vessel plate (120) coupled to the said at least one tube (10) of the said heat-exchange bundle, the opposite surface being formed by the outer face of the said at least one first tube (10).

11. Heat exchanger (1) according to any one of claims 7 to 9, wherein the said phase-change material vessel (12) is delimited by the said first vessel plate (120) and a second vessel plate (120) coupled to the said first vessel plate (120), the opposite surface being formed by the said second vessel plate (120).