WO2011045507A1

WO2011045507A1 - Improved air-conditioning device

Info

Publication number: WO2011045507A1
Application number: PCT/FR2010/052124
Authority: WO
Inventors: Emmanuel Boudard; Vital Bruzzo
Original assignee: Peugeot Citroën Automobiles SA
Priority date: 2009-10-12
Filing date: 2010-10-08
Publication date: 2011-04-21
Also published as: FR2951255B1; CN102656412B; FR2951255A1; CN102656412A; EP2488806A1

Abstract

The invention relates to an air-conditioning device, in particular for a motor vehicle, comprising at least one liquid collection tank (1) including a liquid inlet (11) and a lower liquid outlet (12), said tank being provided with means for automatically sealing the inlet (11) when the level of liquid in the tank (1) is above a pre-determined level.

Description

IMPROVED AIR CONDITIONING DEVICE

The present invention relates to an improved air conditioning device.

It also relates to a motor vehicle, equipped with such an improved air conditioning device.

Among the existing air conditioning devices, there are known absorption air conditioning devices, based on the principle of the absorption of a refrigerant fluid, in gaseous form, by an absorbent fluid. Unlike conventional mechanical compression air-conditioning devices, these non-mechanical absorption air-conditioning devices have few moving parts, which reduces noise and vibration, simplifies maintenance, and improves reliability and durability. of the device.

Efforts have already been made to improve the performance of absorption air conditioning devices in order to be able to easily and reliably place them in vehicles. Thus, for example, the document FR 2 900 723 describes such an air conditioning device comprising an evaporator / absorber assembly composed of porous plates in which the fluids are dispersed, some of which are traversed by the refrigerant fluid to be evaporated, in this case water, and others by the absorbing fluid, in this case a solution of Lithium Bromide.

Such air conditioning devices still need to be improved to be implemented effectively in motor vehicles.

Absorption air conditioning devices comprising two fluid circuits, one of absorbent fluid and the other of refrigerant fluid, require the presence of separate fluid recovery tanks for each of these circuits. These tanks occupy an important place, and the fluids which they are filled weigh heavily. Thus, the volume and weight of these existing devices remain relatively large, and it is necessary to reduce them to effectively adapt such a system in the reduced space of a vehicle.

This reduction in the volume of tanks faces several technical constraints. It is indeed necessary for a sufficient quantity of liquid to fill permanently each circuit of the air conditioning device by absorption.

In particular, the pumps circulating liquids in the circuits must be permanently supplied with liquid to ensure their proper operation and reliability.

On the other hand, when the absorption air conditioning device is stopped, the different liquids tend to descend to the lowest point of the circuit, where the recovery tanks are generally located. If the tanks have an insufficient volume compared to the volume of liquids present in the circuit, there is a risk of overflow of these liquids.

Finally, the absorption air conditioning device requiring a supply of heat, generally from the vehicle engine, to perform the desorption, this desorption can not be done efficiently before the engine is hot. The operation of the air-conditioning device for absorption during the first minutes of operation of the vehicle is therefore done using the absorbent fluid reserves and those of coolant, which are not renewed immediately. The amounts of absorbent fluid and refrigerant in reserve must be sufficient to ensure the correct operation of the air conditioning device during this period during which the desorber does not work. The object of the present invention is therefore to provide an air conditioning device adapted to motor vehicles, which is improved in its operation with respect to known air conditioning or absorption cooling devices of the prior art.

In particular, the object of the present invention is to provide an absorption air conditioning device that allows to offer the same performance with a reduced volume compared to the devices of the prior art.

Another object of the present invention is to provide such an absorption air conditioning device, which is simple in design and whose implementation requires inexpensive technological means.

The invention also aims to provide such an absorption air conditioning device with good reliability, with a simple and effective actuator control system.

These objectives, as well as others which will appear more clearly later, are achieved by an air conditioning device, in particular for a motor vehicle, comprising at least one liquid recovery tank, said tank comprising a liquid inlet opening. and a liquid outlet opening located lower than the liquid inlet opening, the tank being equipped with means for automatically closing said inlet opening when the liquid level in the reservoir is above a predetermined level .

These shutter means make it possible to avoid the overflow of the tank, especially when the air conditioning device is stopped.

Advantageously, the closure means are constituted by a float valve, which comprises for example a lever pivotally mounted in the reservoir and carrying a closure cap of the inlet opening and a float carried by the free end of the lever.

Such a valve is particularly simple to implement.

Advantageously, said reservoir has internal fins preventing the vortex movement of the liquid contained therein.

According to an advantageous embodiment, the reservoir comprises a gas evacuation chimney.

This chimney allows the gases produced by evaporation of the liquid from the tank to be evacuated without generating any disturbance of the arrival of fluid in the tank.

Preferably, this air conditioning device is an air conditioning device absorption.

Preferably, the tank is placed so that stopping the pumps of the air conditioning device causes an increase in the level of liquid in the tank, causing closure of the automatic shut-off means.

The air conditioning device and allows the return of liquids in the tank when it is stopped, while avoiding the overflow of the tank.

Advantageously, the automatic sealing means prevent the complete filling of the reservoir by the liquid, so as to allow the expansion of the liquid contained without damaging the reservoir.

Advantageously, the reservoir is made at least partially in a flexible material, so as to allow the expansion of the liquid contained without damaging the reservoir.

Thus, the tank is not likely to be damaged in case of freezing of the liquid, causing its expansion.

The present invention also relates to a motor vehicle, which comprises a device for improved air conditioning as described above.

Other objects, advantages and features of the invention will appear in the following description of preferred embodiments, not limiting the object and scope of the present patent application, accompanied by drawings in which:

- Figure 1 shows schematically the principle of operation of an air conditioning device by absorption;

- Figure 2 shows, schematically, the functional circuit of an air conditioning device by absorption;

FIG. 3 is a perspective view of an evaporator / absorber assembly of an absorption air conditioning device according to one embodiment of the invention;

FIG. 4 is a section of a liquid recovery tank, or tank, of an air conditioning device according to an embodiment of

The invention;

Figures 5 and 6 are sections of a liquid recovery tank, or tank, an air conditioning device according to another embodiment of the invention.

An absorption air-conditioning device, to which the present invention applies preferentially but not exclusively, implements a double fluid circuit, one carrying a cooling fluid, for example water, and the other an absorbing fluid. for example a lithium bromide salt solution (LiBr).

Figure 1 shows, schematically, the constituent elements and the operating principle of an air conditioning device by absorption. It comprises an element in which the desorption takes place, designated "desorber" 100 in the rest of the text, a condenser 200, an evaporator 300 and an absorber 400.

The desorber 100 and the absorber 400 are filled with a mixture of at least two miscible substances formed by the coolant and the absorbent fluid. This mixture is combined in absorber 400, wherein the absorbent fluid absorbs refrigerant under vapor phase.

The refrigerating fluid and the absorbing fluid have sufficiently different evaporating pressures so that, when the mixture is heated in the desorber 100, the refrigerant, more volatile, evaporates, allowing the separation of the two fluids. The heat necessary for this separation (contribution illustrated schematically by the arrow A) can advantageously be provided to the desorber by the engine coolant of the vehicle.

The refrigerant in the form of steam is then fed through the pipe 120 into the condenser 200 to be condensed by the cooling action of the outside air (cooling contribution schematically illustrated by the arrow B).

The refrigerant fluid in the liquid phase is then fed through the pipe 210 to the evaporator 300. The cold produced during the evaporation of this refrigerant fluid is transmitted to the passenger compartment of the vehicle (not shown), as schematically illustrated by the arrow C. To this end, there is provided a heater 320, which is connected to a pump 310 and to the evaporator 300 through the pipes 311 and 313.

The refrigerant vapor exiting the evaporator 300 is fed into the absorber 400 through the conduit 21 which is formed by the envelope of the absorber / evaporator assembly. The absorbing fluid, which has been cooled by external air in the absorbent solution circuit (cooling input schematically illustrated by the arrow D), then absorbs this refrigerant vapor to reform the mixture.

The absorbent solution circuit is formed by a radiator 420, which is connected to the pump 410 and the absorber 400 through the pipes 416, 417 and 419. The absorber 400 is connected to the desorber 100 via the pipes 414, 415 and 416 .

Figure 2 shows the functional circuit of an absorption air conditioning to which the present invention can be applied. By way of non-limiting example, it is an absorption machine that uses the LiBr-water pair (lithium bromide as absorbent fluid and water as coolant).

Elements of the circuit identical or similar to elements of Figure 1 are designated, most often, by the same reference numeral. The references 100 and 200 respectively denote the desorber and the coolant condenser. References 320 and 420 respectively designate the coolant heater and the radiator of the absorbent fluid.

References 310 and 410 respectively designate the refrigerant circuit pump and the absorbent fluid circuit pump. References 350 and 450 respectively denote the refrigerant reserve and the absorbent fluid reserve. References 62 and 63 denote check valves, and reference numeral 120 denotes the pipe bringing water vapor from desorber 100 to condenser 200.

Reference 500 denotes an assembly that combines the absorber and the evaporator of the air-conditioning device by absorption. In this evaporator / absorber assembly, traversed by a flow of refrigerant fluid and an absorbent fluid flow, a part of the refrigerant is evaporated, and this endothermic evaporation reaction has the effect of cooling the flow of refrigerant remaining. The vapor produced is directly absorbed by the flow of absorbent fluid. FIG. 3 represents a perspective view of certain elements of such an evaporator / absorber assembly, showing two distinct circuits, one traversed with refrigerant fluid and exerting the evaporator function, and the other traversed with absorbent fluid and exerting the absorber function.

The circuit traversed by the cooling fluid, in liquid form, comprises a refrigerant supply pipe 301, supplying a fluid to a refrigerant distribution box 302 which distributes the refrigerant in a plurality of evaporating frames 330 extending vertically and parallel to each other. In each evaporation frame 330, the refrigerant circulates, essentially by gravity, in a dispersion plate (not shown in FIG. 3), and a portion of the fluid evaporates.

The unvaporated refrigerant, cooled by the evaporation reaction, exits the evaporation frame 330 through its fluid outlet opening 332, and enters the refrigerant recovery tank 350.

The circuit traversed by the absorbing fluid is very similar to the circuit traversed by the refrigerant fluid. It thus comprises an absorbent fluid supply pipe 401, supplying fluid to an absorbent fluid distribution box 402 which distributes the absorbing fluid in a plurality of absorption frames 430 extending vertically parallel to one another, and parallel to the evaporation frames 330 with which they are alternated.

The absorbent fluid circulates, essentially by gravity, in a dispersion plate (not shown in Figure 3) of the absorption frame 430, and absorbs refrigerant vapors. It exits the absorption frame 430 through its fluid outlet opening 432, and arrives in the absorbent fluid reservoir 450. Of course, the evaporator / absorber assembly shown in FIG. 3 is incorporated in a sealed housing (not shown) avoiding gas exchange with the outside.

The coolant reservoir 350 and the absorbent fluid reservoir 450 serve to store the fluids, in liquid form, before they are returned to the circuit by the pumps located downstream of the tanks. They allow enough fluid to fill each of the two circuits during system operation.

Indeed, when the absorbent fluid absorbs refrigerant vapor, its volume increases while the refrigerant volume decreases almost the same amount. The difference in volume can thus be relatively large, for example during the start-up phase of the air conditioning.

Thus, if the absorbent fluid is lightly charged with refrigerant, its volume decreases while its salt concentration increases. The absorption reaction is then more efficient. Depending on its salt concentration, this absorbent fluid is more or less sensitive to freezing or crystallization, the solutions too or not enough concentrated being more sensitive. Thus, for example, LiBr saline solution with 10% mass concentration of LiBr freezes at a temperature of -5 ° C, the same salt solution at 50% concentration freezes at a temperature of -42 ° C, saline solution at 54% concentration freezes at a temperature of -16 ° C, and the saline solution at 62% concentration freezes at + 28 ° C.

The fluids must be present in the circuits in sufficient quantity so that the salt concentration of the saline solution can be kept within limits allowing the correct operation, whatever the phase of operation of the air conditioning device (start up, operation at maximum power , etc.). In addition, the tanks can store at least a portion of the fluid when the air conditioning device is stopped. Indeed, if the vehicle is stopped under low temperature conditions, there is a risk that the fluids freeze and damage or block the circuits. Since the tanks can be relatively easily isolated from the cold, they can protect the fluids contained in it for a certain period of time.

In addition, these tanks can be designed so as not to be damaged in case of freezing of their contents. They can thus be made of materials having a certain elasticity, such as for example a plastic, or have zones of preferential deformation which can deform elastically in case of freezing of the fluid, causing its expansion. It can also be provided in the tanks volumes being filled that no gas, and can not be filled with a liquid. These volumes can absorb the expansion of the fluid during its phase change from liquid to solid.

However, it should be noted that the volume of tanks and fluids stored must remain relatively small compared to the total volume of fluids present in the circuit, to avoid congestion and excessive weight of the air conditioning device.

FIG. 4 is a sectional view of a reservoir for recovering a liquid according to a possible embodiment of the invention.

This tank 1 comprises in the upper part an inlet opening 11, through which the liquids enter the tank, and in the lower part an outlet opening 12 through which the liquids leave the tank. A pump 2 is mounted in the outlet pipe, close to the outlet opening 12, for send liquids contained in the tank 1 into the circuit 1.

This pump 2, in the example shown, is of the centrifugal type and comprises a motor 21 and a wheel 22 (shown in phantom) rotating about the axis 23, which draws the liquid through the outlet opening 12 of the tank 1 and pushes it back into line 24.

When the air conditioning is stopped, either because the user turns off the engine or switches off the air conditioning, or in case of failure, the pump 2 no longer moves the liquids, which then tend to fall to the lowest point of the circuit . Since the tank 1 is placed at the bottom of the circuit, a large part of the liquids contained in the circuit flow back into the tank 1 through the outlet opening 12 after passing through the pump 2 in the opposite direction to the normal circulation of the liquid.

This return of liquids in the tank is of interest in case of stopping the vehicle in low temperature conditions. Indeed, in this case, the liquids present in the circuits can freeze, which can cause a bursting or blockage of the pipes. The tank 1 can relatively easily be thermally insulated, it can protect the gel liquid it contains.

However, if too much liquid flows back into the tank, it may overflow through the inlet opening 11 thereof, and cause the level of the evaporator / absorber assembly overflows may cause a mixture of absorbent and refrigerant fluids.

To avoid such an overflow, the inlet opening 11 of the tank 1 is equipped with a float valve 4. This valve comprises a plug 41 and a float 42 mounted on a lever 43, itself pivotally mounted relative to the reservoir 1 about an axis 44. The float is secured to the free end of the lever 43. When the liquid level is low in the tank 1, the float, depending on the level of the liquid, is in the low position and keeps the cap in an open position, in which it does not close the inlet opening 11 In contrast, when the liquid volume is high in the tank 1, as shown in FIG. 4, the float is in a high position and holds the cap in a closed position, closing the inlet opening 11.

Thus, when the reservoir 1 is full or has reached a sufficient level, the float valve system 4 closes the fluid circuit and prevents the return to the reservoir of liquids located in the pipes downstream of the reservoir, but located higher than this one.

On the contrary, when the reservoir 1 is not sufficiently filled with liquid, the float valve system 4 is open, which allows on the one hand the normal operation of the air conditioning device, during which the liquid enters the reservoir 1 through the inlet opening 11, and secondly, when the air conditioning device is stopped, the return in the tank of the liquids contained in the pipes downstream of the tank.

When restarting the air conditioning device after a stop, the pump 2 circulates in the pipes and the various organs of the device the fluids contained in the tank. The fluid level drops accordingly, which naturally leads to the opening of the valve 4.

The valve system 4, which is particularly simple to produce and therefore inexpensive, therefore optimizes the operation of the air conditioning device.

FIGS. 5 and 6 show the implementation of this float valve 4 comprising a plug 41 and a float 42 mounted on a lever 43, itself pivotally mounted about an axis 44, in a tank 3 of a different type than that shown in Figure 4. When the liquid level is low in the tank, as shown in Figure 5, the plug 41 is in a position in which it does not close the inlet opening 31 of the tank 3.

In contrast, when the liquid level is high as shown in Figure 6, the plug 41 is in a position in which it closes the inlet opening 31 of the tank 3. It thus avoids the overflows of the tank.

It should be noted that the float valve 4 can be equipped with several plugs in the case where, as shown in Figure 3, a tank has a plurality of inlet openings. Furthermore, it may also include means for blocking other openings in the tank, such as for example gas evacuation chimneys.

Advantageously, it can be provided that the float valve is placed in the closed position while the reservoir is not completely filled with liquid. This situation is advantageous in case of freezing of the reservoir, which causes an expansion of the fluid that freezes. The portion of the tank that is not filled with fluid can indeed absorb this expansion without this causing damage to the tank.

According to one particular characteristic that can be implemented in one embodiment of the invention, fins may extend vertically in the tank 1 so as to prevent the liquids from rotating, or by swirling, in the latter. this. Such fins can contribute to the stiffening of the tank. By avoiding the vortex movement of the liquid, they prevent the upper surface thereof from forming a cone, the tip of which could introduce gas into the pump 2 and disrupt the operation. It should be noted that these fins can be implemented in an air conditioning system tank independently of the other features of the present invention.

According to another characteristic that can be implemented on a tank of the type shown, it is possible, to prevent the steam generated by the arrival of hot refrigerant does not cause disturbance in the refrigerant tank, to equip the tank a steam vent opening into the evaporator / absorber assembly. Figure 3 shows an example of such a chimney 9 implemented on the refrigerant reservoir 350. This chimney must be higher than the maximum permissible level of fluid in the circuit, to prevent fluid overflow. If necessary, a float valve similar to the valve 4 can be implemented to close the chimney when the tank is sufficiently filled.

The present invention offers many advantages, among which the following advantages:

it makes it possible, with simple and inexpensive technological means, to improve the operation of the absorption air conditioning device adapted to a motor vehicle,

- It reduces the volume of the air conditioning system.

Of course, the present invention is not limited to the embodiments described and represented above by way of examples; other embodiments may be devised by those skilled in the art without departing from the scope and scope of the present invention.

Claims

An air conditioning device, in particular for a motor vehicle, comprising at least one liquid recovery reservoir (350, 450, 1, 3), comprising a liquid inlet opening (11, 31) and an outlet opening of liquid (12) lower than said liquid inlet opening,

characterized in that said tank is equipped with means for automatically closing said inlet opening when the liquid level in the tank is above a predetermined level.

2. An air conditioning device according to claim 1, characterized in that said closure means are constituted by a float valve (4).

3. An air conditioning device according to claim 2, characterized in that said float valve (4) comprises a lever (43) pivotally mounted in said reservoir (1, 3) and carrying a plug (41) for closing the inlet opening and a float (42) carried by the free end of the lever (43).

4. An air conditioning device according to any one of claims 1 to 3 characterized in that said reservoir comprises internal fins preventing vortex movement of the liquid it contains.

5. An air conditioning device according to any one of claims 1 to 4 characterized in that said tank (350) comprises a chimney (9) for evacuation of gases.

6. An air conditioning device according to any one of claims 1 to 5 characterized in that it constitutes an air conditioning device absorption.

7. An air conditioning device according to any one of claims 1 to 6 characterized in that that the tank (350, 450, 1, 3) is placed so that the shutdown of the pumps (2) of the air conditioning device causes an increase in the level of liquid in the tank, causing closure of the closure means automatic.

8. An air conditioning device according to any one of claims 1 to 7 characterized in that the automatic sealing means prevent the complete filling of the reservoir (350, 450, 1, 3) by the liquid, so as to allow the expansion of the contained liquid without damaging the tank.

9. An air conditioning device according to any one of claims 1 to 8 characterized in that the reservoir (350, 450, 1, 3) is made at least partially in a flexible material, so as to allow the expansion of the liquid content without damaging the tank.

10. Motor vehicle, characterized in that it comprises an air conditioning device according to any one of claims 1 to 9.