WO2015071031A1

WO2015071031A1 - Thermal conditioning device for a motor vehicle and corresponding heating, ventilation and/or air-conditioning facility

Info

Publication number: WO2015071031A1
Application number: PCT/EP2014/071514
Authority: WO
Inventors: Josselin GOUR; Bernard Aoun; Abdelillah LAKHAL
Original assignee: Valeo Systemes Thermiques
Priority date: 2013-11-18
Filing date: 2014-10-08
Publication date: 2015-05-21
Also published as: FR3013266B1; FR3013266A1

Abstract

The invention relates to a thermal conditioning system for a flow of air for a motor vehicle comprising a refrigerant circuit (3) and a heat transfer fluid circuit (5), said refrigerant circuit (3) comprising: - a first heat exchanger (9) for heat exchange with a flow of outside air (FE), - a second heat exchanger (11) to condition a flow of air intended for the passenger compartment of said vehicle, and - a water condenser (15) jointly with the heat transfer fluid circuit (5). The refrigerant circuit (3) further comprises a third heat exchanger (13) and an expander member (14) arranged upstream from the third heat exchanger (13) and connected to the outlet of the water condenser (15). The third heat exchanger (13) is configured to work as a supercooling exchanger or an evaporator. The invention also relates to a corresponding heating, ventilation and/or air-conditioning facility.

Description

THERMAL CONDITIONING SYSTEM FOR MOTOR VEHICLE AND HEATING, VENTILATION AND / OR HEATING INSTALLATION

CORRESPONDING AIR CONDITIONING The invention is in the field of heating, ventilation and / or air conditioning of an electric or hybrid motor vehicle. The subject of the invention is a thermal conditioning system cooperating with such an installation.

A motor vehicle is commonly equipped with a ventilation, heating and / or air conditioning system to modify the air contained inside the passenger compartment of the vehicle by delivering a flow of conditioned air inside the vehicle. cabin.

Such an installation generally comprises an air conditioning system that can be controlled according to various operating modes, such as a heating mode or "heat pump" mode making it possible to meet a heating need of the passenger compartment, or an air conditioning mode to cool the air to the passenger compartment, or a dehumidification mode to dry air to the passenger compartment. It is therefore a reversible architecture.

According to a known solution, the conditioning system comprises an air conditioning loop inside which circulates a refrigerant.

In the traditional way, the air conditioning loop or refrigerant circuit comprises a compressor for compressing the refrigerant fluid, a first heat exchanger arranged on the front face such as an external evaporator, a second heat exchanger arranged to condition the air flow to destination of the passenger compartment such as an internal evaporator.

The compressor is able to carry the refrigerant at a high pressure.

The first heat exchanger allows a heat transfer between the refrigerant and the ambient air, such as a flow of air outside the vehicle.

The second heat exchanger allows a heat exchange between the refrigerant and the air flow to be delivered inside the passenger compartment that passes through the second heat exchanger. The second internal heat exchanger is generally an internal evaporator for cooling the flow of air therethrough.

An expansion member is provided upstream of each evaporator of the cooling system. air conditioning according to the direction of circulation of the refrigerant to lower the pressure and the temperature before evaporation.

Refrigerant fluid circuits are known comprising a so-called internal condenser for heating the flow of air to the passenger compartment. In this case the conditioning system is commonly called direct system.

Conditioning systems are also known comprising a secondary heat transfer fluid circuit. The refrigerant circuit then comprises, together with the coolant circuit, a water condenser in which the coolant transfers heat to the coolant. In this case the air flow to the passenger compartment is heated by the heat transfer fluid flowing in the secondary circuit. In this case we speak of an indirect system.

Conventionally, when the system is controlled in air conditioning mode, the condensed refrigerant then evaporates in the internal evaporator absorbing the calories of the air flow to the passenger compartment.

In order to improve the performance in the air-conditioning mode, it is possible to provide an undercooling of the condensed refrigerant fluid before it passes through the internal evaporator. For this, the air conditioning system may comprise a subcooling exchanger arranged on the front of the vehicle for a heat exchange between the refrigerant and the outside air flow. Such a subcooling exchanger is also called external condenser.

However, with such an architecture, when the air conditioning system is controlled in a heat pump mode, the condensed refrigerant is first subcooled and thus removes calories to the outside before passing through. external evaporator in which it absorbs the calories of the outside air flow. The refrigerant then returns to the condenser or bi-fluid heat exchanger in which the coolant transfers the calories recovered from the outside to the heat transfer fluid.

During subcooling, the refrigerant therefore transfers calories to the outside air flow within the subcooling exchanger, degrading the performance of the air conditioning system in heat pump mode. An object of the present invention is to provide a conditioning system for a sufficient supply of energy in heat pump mode and improved performance benefiting from a subcooling condensed refrigerant in cooling mode.

For this purpose, the subject of the invention is a thermal conditioning system for an air flow for a motor vehicle comprising a refrigerant circuit and a coolant circuit, said refrigerant circuit comprising:

at least one first heat exchanger arranged for a heat exchange between the refrigerant and an outside air flow,

a second heat exchanger arranged so as to condition a flow of air to the passenger compartment of said vehicle by heat exchange, and

a water condenser in conjunction with the coolant circuit for condensing the coolant, with a heat exchange between the coolant and the coolant,

characterized in that

the refrigerant circuit further comprises:

A third heat exchanger arranged for a heat exchange between the refrigerant and the outside air flow and

An expansion member arranged upstream of the third heat exchanger in the direction of circulation of the refrigerant fluid and connected to the outlet of the water condenser, and in that

the third heat exchanger is configured to work in a sub-cooling exchanger or in an evaporator.

With this architecture, the air conditioning system benefits from the subcooling of the refrigerant, especially when it is controlled in air conditioning mode or dehumidification does not require a significant heating of the passenger compartment, to evacuate calories to outside, without degrading performance when the air conditioning system is to be driven in heat pump or dehumidifcation meeting a strong need for heating. Indeed, when the air conditioning system is controlled in a heat pump or dehumidification mode meeting a strong need for heating, the heat exchanger initially provided for subcooling is then used as an evaporator and absorbs heat. calories from the outside.

Thus, in a control mode meeting a need for heating the cabin, there is more energy loss with the outside air within the third heat exchanger.

All the energy of the refrigerant at the outlet of the water condenser can be restored in particular at the first and / or second heat exchanger (s) working in evaporator (s).

According to one aspect of the invention, the expansion element upstream of the third heat exchanger can be configured for expansion of the refrigerant fluid before evaporation of the refrigerant fluid by heat exchange with the external air flow within the third heat exchanger, when the third heat exchanger works in an evaporator.

The expansion element upstream of the third heat exchanger can be configured for expansion of the refrigerant fluid before subcooling the refrigerant fluid by heat exchange with the external air flow within the third heat exchanger, when the third heat exchanger is working. in subcooling exchanger.

In particular, this allows the refrigerant to be expanded or not before it passes through the third heat exchanger when it is controlled by a subcooling exchanger so as to vary the pressure of the third subcooling exchanger and thus to vary the heat exchange. with the outside air flow so as to more or less reduce the heating.

Said air conditioning system may further comprise one or more of the following features, taken separately or in combination: - The first heat exchanger is arranged downstream of the third heat exchanger in the direction of circulation of the refrigerant. The refrigerant fluid at the outlet of the third heat exchanger can therefore be directed towards the first heat exchanger, in particular for evaporation so as to absorb calories from the outside air flow,

the second heat exchanger is arranged downstream of the third heat exchanger in the direction of circulation of the refrigerant fluid, the refrigerant fluid at the outlet of the third heat exchanger can therefore be directed towards the second heat exchanger in particular for evaporation so as to cool the flow air to the passenger compartment,

the second heat exchanger is arranged for a circulation of the refrigerant fluid parallel to the circulation of the refrigerant fluid in the first heat exchanger. The refrigerant fluid at the outlet of the third heat exchanger can therefore be directed towards the first heat exchanger and in parallel to the second heat exchanger, in particular for two evaporations so as to absorb calories both on the front face of the vehicle and on the inside the installation,

the first heat exchanger is a first evaporator and in which an expansion element is arranged upstream of the first heat exchanger in the direction of circulation of the refrigerant fluid,

the second heat exchanger is a second evaporator and an expansion member is arranged upstream of the second heat exchanger in the direction of circulation of the refrigerant,

- The coolant circuit comprises a heat exchanger for heating the air flow to the passenger compartment arranged downstream of the second heat exchanger in the direction of flow of the air flow to the passenger compartment.

The invention also relates to a heating, ventilation and / or air conditioning system comprising a thermal conditioning system of an air flow as defined above. Other features and advantages of the invention will emerge more clearly on reading the following description, given by way of illustrative and nonlimiting example, and the appended figures among which:

FIG. 1 represents an air conditioning system according to the invention,

FIG. 2a represents the system of FIG. 1 operating in an air conditioning mode,

FIG. 2b is a Mollier diagram representing the refrigerant cycle when the air conditioning system is controlled in the air-conditioning mode illustrated in FIG. 2a,

FIG. 3a represents the system of FIG. 1 operating in a first mode of heat pump,

FIG. 3b is a Mollier diagram representing the refrigerant cycle when the air conditioning system is controlled in the first heat pump mode illustrated in FIG. 3a,

FIG. 4a represents the system of FIG. 1 operating in a second heat pump mode,

FIG. 4b is a Mollier diagram representing the refrigerant cycle when the air conditioning system is controlled in the second heat pump mode illustrated in FIG. 4a,

FIG. 5 represents the system of FIG. 1 operating in a first mode of dehumidification,

FIG. 6a shows the system of FIG. 1 operating in a second mode of dehumidification,

FIG. 6b is a Mollier diagram showing a first example of a refrigerant cycle when the air conditioning system is controlled in the second dehumidification mode illustrated in FIG. 6a,

FIG. 6c is a Mollier diagram showing a second example of a refrigerant cycle when the air conditioning system is controlled in the second dehumidification mode illustrated in FIG. 6a, FIG. 7a represents the system of FIG. 1 operating in a third mode of dehumidification,

FIG. 7b is a diagram of Mo Hier showing a first example of a refrigerant cycle when the air conditioning system is controlled in the third dehumidification mode illustrated in FIG. 7a,

FIG. 7c is a diagram of Mo Hier showing a second example of a refrigerant cycle when the air conditioning system is controlled in the third dehumidification mode illustrated in FIG. 7a, and

FIG. 8 represents a fourth mode of dehumidification for an air conditioning system of a vehicle comprising a heat engine.

In these figures, the substantially identical elements bear the same references.

Figure 1 shows schematically and simplified an air conditioning system 1 of a heating, ventilation and / or air conditioning system for a motor vehicle.

Such an air conditioning system 1 makes it possible to modify the parameters of the air inside the passenger compartment of the vehicle by delivering a flow of air inside the passenger compartment.

For this purpose, the air conditioning system 1 may comprise a blower (not shown) for circulating the air flow for example from an air inlet (not shown) to a delivery port of air (not shown) in the passenger compartment. It may include a defrosting / defogging mouth intended to deliver the flow of air to the windshield and / or the front windows of the vehicle.

Such an air conditioning system 1 can operate in different modes, in particular in heat pump mode to meet a need for heating the cabin, or an air conditioning mode for conditioning the air flow to the air. cockpit of the vehicle to cool, or at least a dehumidification mode to obtain a flow of dry air before distributing it in the cabin as described below. According to the embodiment illustrated in Figure 1, the air conditioning system 1 comprises a refrigerant circuit 3, and a coolant circuit 5 such as a mixture of water and glycol. The refrigerant circuit 3 is also called air conditioning loop 3.

The components of the refrigerant circuit 3 are connected to each other by pipes or pipes through which the coolant flows.

Respectively the components of the heat transfer fluid circuit 5 are connected to each other by pipes or pipes through which the heat transfer fluid circulates.

In the figures, the refrigerant circuit 3 is shown in dotted lines and the coolant circuit 5 is shown in solid lines.

The flow direction of the fluids is schematized by arrows. Of course, the direction of movement shown in the figures is for illustrative and not limiting.

According to the embodiment illustrated in FIG. 1, the refrigerant circuit 3 comprises:

a compressor 7,

a first heat exchanger 9, for a heat exchange between the refrigerant and an outside air flow FE, here a first evaporator 9,

a second heat exchanger 11 arranged to condition a flow of air to the passenger compartment of the vehicle, here a second evaporator 11,

a third heat exchanger 13 suitable for working in a subcooling or subcooler exchanger or "subcooler" in English, for undercooling the refrigerant, and also suitable for working in an evaporator and

- At least one expansion member 14 arranged upstream of the third heat exchanger 13 in the direction of circulation of the refrigerant.

The refrigerant circuit 3 further comprises a condenser 15. According to the illustrated embodiment, the refrigerant circuit 3 comprises, together with the coolant circuit 5, the condenser 15 for condensing the fluid refrigerant with a heat exchange with the coolant. The heat transfer fluid is for example water, it is called water condenser or "water condenser" in English.

A refrigerant storage bottle 16 may be provided in series with the water condenser 15. The storage bottle 16 stores the liquid coolant to compensate for any volume changes.

In operation, the compressor 7 receives as input the refrigerant fluid in the gaseous state, or a mixture of gas / liquid, under low pressure and low temperature, as schematically illustrated by the abbreviation "BP" above the pipes on the figures.

The compressor 7 thus comprises an inlet orifice through which the coolant enters and an outlet orifice through which the compressed refrigerant fluid exits.

Compression can raise the pressure and temperature of the refrigerant, as schematically illustrated by the acronym "HP" above the pipes in the figures.

The first heat exchanger 9, here a first evaporator 9, is for example arranged in the vehicle at the front of the vehicle to be traversed by a stream of air FE from outside the vehicle. We also talk about external exchanger.

In operation, the refrigerant evaporates in the first evaporator 9, and by evaporating the refrigerant absorbs heat from the airflow FE passing through the first evaporator 9.

An expansion member 17 is for example arranged in series with the first evaporator 9. More specifically, the first expansion member 17 is arranged upstream of the first evaporator 9 in the direction of circulation of the refrigerant, in particular in at least one pump mode. heat as described later.

Indeed, in at least one heat pump mode described below, the refrigerant circulates in series in the first expansion member 17 and in the first evaporator 9, so as to lower the pressure and temperature of the refrigerant before evaporation.

As regards the second heat exchanger 11, it is generally described as "internal exchanger" because it is arranged to exchange calories with the air flow to be distributed inside the passenger compartment.

The second heat exchanger 11 is according to the embodiment described a second evaporator.

In operation, the refrigerant entering the second heat exchanger 11 absorbs the heat of the air flow to the passenger compartment by evaporating; which has the effect of cooling the airflow.

The second heat exchanger 11 may be arranged to allow a circulation of the refrigerant fluid within it substantially parallel to the flow of refrigerant in the first evaporator 9, in terms of fluid flow.

In addition, a second expansion member 19 may be arranged in series with the second heat exchanger 11. More specifically, the second expansion member 19 is arranged upstream of the second heat exchanger 11 in the direction of circulation of the refrigerant. Moreover, the refrigerant circuit 3 further comprises a first connection point 21 arranged at the outlet of the first evaporator 9 and at the outlet of the second evaporator 11, for channeling the refrigerant towards the compressor 7.

Regarding the third heat exchanger 13, it is arranged at the front of the vehicle to be traversed by the outside air flow FE and is arranged in series with the water condenser 15.

As said before, it is able to work as a subcooling exchanger 13. In this case it is an external subcooling exchanger. The subcooling of the refrigerant at the outlet of the water condenser 15 is achieved by heat exchange with the external air flow FE. The third heat exchanger is also able to work as an evaporator.

In operation, the refrigerant evaporates in the third evaporator 13, and by evaporating the refrigerant absorbs heat from the airflow FE through the third evaporator 13.

In addition, the expansion member 14 arranged in series with the third evaporator 13, more precisely upstream of the third evaporator 13 in the direction of circulation of the refrigerant fluid, is able to relax the refrigerant to lower its pressure and temperature. before evaporation, in particular in at least one heat pump mode or at least one dehumidification mode as described below, but also before subcooling of the cooling fluid in the third heat exchanger, for example in at least one dehumidifying mode .

In this example, the refrigerant circuit 3 further comprises a connection point 23 connected to the outlet of the third heat exchanger 13 and to the inlet of the second evaporator 11.

Furthermore, according to the arrangement shown in Figure 1, the water condenser 15 is arranged at the outlet of the compressor 7. In operation, the water condenser 15 receives the refrigerant in the form of hot gas which gives heat to the fluid coolant.

Heat transfer fluid circuit

With regard to the coolant circuit 5, the latter comprises a heat exchanger 25 arranged to condition the flow of air to the passenger compartment.

More specifically, the heat exchanger 25 of the coolant circuit 5 is provided so as to heat the flow of air to the passenger compartment.

This is for example a heating radiator commonly called "heater core" in English.

According to the illustrated embodiment, the heating radiator 25 is arranged in downstream of the second heat exchanger 11 according to the direction of flow of the air flow to the passenger compartment of the vehicle.

This arrangement is particularly advantageous for dehumidifying the flow of air to the passenger compartment for example by cooling it by passing through the second evaporator 11 before heating the air flow by passing through the heating radiator 25 of the cooling circuit. heat transfer fluid 5.

The heat transfer fluid circuit 5 may comprise an optional additional electrical heat exchanger (not shown), for example by electric resistance heating, arranged in series with the water condenser 15.

The additional electric heat exchanger (not shown) can be arranged in series between the water condenser 15 and the heating radiator 25. In particular, the additional electrical heat exchanger (not shown) can be arranged downstream of the water condenser 15 and upstream of the heating radiator 25, in the direction of circulation of the coolant.

The heat transfer fluid circuit 5 may also include a radiator 27, such as a cooling radiator 27, arranged on the front of the vehicle.

In addition, the coolant circuit 5 may include a pump 29 for the circulation of the coolant.

The heat transfer fluid circuit 5 may also include one or more control valves, for example a first control valve 31 and a second control valve 33, for directing the coolant according to the operating mode of the air conditioning system. 1.

The heat transfer fluid circuit 5 also comprises a first connection point 35 to which is connected the outlet of the water condenser 15 or of an additional heat exchanger (not shown) at the outlet of the water condenser 15.

The connection point 35 of the coolant circuit 5 is also connected firstly to the first control valve 31 upstream of the low-temperature radiator 27 in the direction of circulation of the coolant, for example in an air-conditioning or air-conditioning mode. dehumidification and secondly to the second control valve 33 upstream of the heating radiator 25 according to the direction of flow of the coolant.

The first control valve 31 of the heat transfer fluid circuit 5 is for example a two-way valve.

The second control valve 33 of the heat transfer fluid circuit 5 may for example be a two-way valve or a three-way valve.

Thus, while flowing to the connection point 35, the heat transfer fluid can subsequently flow to the cooling radiator 27, for example in the air-conditioning mode and / or to the heating radiator 25, for example in heat pump mode, or still in at least one mode of dehumidification as will be described later.

The circulation of the coolant in the cooling radiator 27 or the heating radiator 25 is thus placed under the control of the first control valve 31 and the second control valve 33 of the coolant circuit 5.

The heat transfer fluid circuit 5 furthermore comprises, in this example, a second connection point 36 arranged at the outlet of the cooling radiator 27 and at the outlet of the heating radiator 25, for channeling the cooling fluid towards the pump 29. Finally, the air conditioning system 1 may also include an additional heat exchanger 37, for example by electrical resistance with a positive temperature coefficient CTP, arranged to heat the flow of air to the passenger compartment, for example in addition to the radiator of heater 25 or "heater core" in English. It is therefore a heating said on the air.

The additional heat exchanger 37 said on the air can in this case be arranged downstream of the heating radiator 25 in the direction of flow of the air flow to the passenger compartment.

The control of the air conditioning system 1 is now described in more detail according to various modes of operation, such as an air conditioning mode, heat pump modes, or dehumidification. Air conditioning mode

Figure 2a is a schematic view of the air conditioning system 1 implemented in an air conditioning mode corresponding to a need for cooling of the passenger compartment of the vehicle.

According to the air conditioning mode for conditioning the flow of air to the passenger compartment of the vehicle to cool, the refrigerant at the outlet of the compressor 7 is first condensed, then can be subcooled before undergoing a relaxation upstream of the second evaporator 11. The flow of air to the passenger compartment passing through the second evaporator 11 is then cooled.

FIG. 2b is a diagrammatic representation of a cycle of the refrigerating fluid in the Mo Hier diagram when the air conditioning system 1 is controlled according to this cooling mode, with the abscissa H in kJ / kg. and in ordinate the pressure P in Bars.

On this diagram of Mo Hier, schematically in terms of thermodynamics:

point 1A / C corresponds to the output of the second evaporator 11 and to the inlet of the compressor 7,

point 2A / C corresponds to the output of the compressor 7 and to the inlet of the water condenser 15,

point 3A / C corresponds to the outlet of the water condenser 15 and to the inlet of the third heat exchanger 13 in subcooler mode,

point 4A / C corresponds to the output of the third heat exchanger 13 and to the inlet of the expansion member 19,

point 5A / C corresponds to the output of the expansion element 19 and to the inlet of the second evaporator 11.

According to this air conditioning mode, from 1A / C to 2A / C, the refrigerant is sucked by the compressor 7 and is compressed from a low pressure BP to a high pressure HP.

Then, the air conditioning system 1 is controlled so that the refrigerant circulates from the compressor 7 to the water condenser 15. From 2A / C to 3A / C on the diagram of Mo Yesterday, passing through the water condenser 15, the refrigerant fluid in the gaseous state compressed at high pressure HP, high temperature, gives up heat to the coolant flowing in the coolant circuit 5.

The heat transfer fluid and the refrigerant fluid respectively leave the water condenser 15.

The coolant having yielded heat to the coolant in the water condenser 15 leaves the water condenser 15 and then flows from the storage bottle 16 to the third heat exchanger 13 acting as external subcooling exchanger 13.

From 3A / C to 4 _{A /} c on the diagram of Mo Yesterday, the condensed refrigerant fluid passes through the third heat exchanger 13 operating in external subcooling exchanger 13 for a subcooling of the refrigerant fluid by heat exchange with the flow of outside air FE. This allows the evacuation of calories to the outside.

The cooling fluid subcooled after condensation is then directed for example to the connection point 23 connected to the output of the third heat exchanger and to the inlet of the first and second heat exchangers 9, 11. The refrigerant is then directed to the second expansion member 19 and undergoes isenthalpic expansion. This corresponds to points 4A / C at 5A / C on the Mollier diagram.

The refrigerant then flows from 5A / C to _{A /} c in the second evaporator 11. The expansion allows to lower the pressure and temperature of the refrigerant.

During the passage in the second evaporator 11, the cooling fluid while evaporating absorbs the heat of the air flow through the second evaporator 11 to the passenger compartment. The flow of air to the passenger compartment passing through the second evaporator 11 is thereby cooled.

By reaching the vehicle interior, for example under the action of a blower (not shown), the cooled air flow reduces the air temperature of the passenger compartment. The refrigerant then leaves the second evaporator 11 and returns to the compressor 7 to restart a refrigerant cycle, for example through the connection point 21 of the refrigerant circuit 3.

Between the second expansion member 19 and the inlet of the compressor 7, the coolant is at low pressure and low temperature.

As regards the coolant, the latter is for example set in motion by the pump 29.

The heat transfer fluid passes through the water condenser 15 in which the coolant absorbs the heat of the coolant.

The heat transfer fluid then passes through the cooling radiator 27, where it gives calories to the outside air flow FE. This is according to the described embodiment of a cooling radiator called "low temperature". For this, arriving at the connection point 35 of the coolant circuit 5, the heat transfer fluid is directed towards the cooling radiator 27 by driving the first control valve 31.

In cooling mode, the cooling radiator 27 is used to cool the heat transfer fluid from the water condenser 15 by heat exchange with the outside air flow FE.

The cooling radiator 27 further has an outlet through which the cooled heat transfer fluid leaves the cooling radiator 27 to be directed back to the water condenser 15, possibly being circulated by the pump 29.

By cooling the heat transfer fluid, the cooling radiator 27 thus makes it possible to cool the water condenser 15.

First mode of heat pump

With reference to FIGS. 3a and 3b, a first heat pump mode corresponding to a need for heating the passenger compartment of the vehicle is described.

According to this first mode of heat pump, after condensation a first evaporation of the refrigerant with a heat exchange between the refrigerant and the external air flow FE in the third heat exchanger 13 followed by a second evaporation also in the front face within the first evaporator 9.

In the front panel, the refrigerant absorbs calories from the outside air flow

FE before giving them to the coolant in the water condenser 15.

The heated heat transfer fluid then transfers heat to the flow of air to the passenger compartment passing through the heating radiator 25.

Diagram 3b shows schematically a Mo Hier diagram of a refrigerant cycle when the air conditioning system 1 is controlled according to this first heat pump mode, with the abscissa H enthalpy kJ / kg and in ordinate the pressure P in Bars.

On this diagram of Mo Hier, schematically and in terms of thermodynamics:

the point lp corresponds to the output of the first evaporator 9 and to the inlet of the compressor 7,

point 2 _P corresponds to the output of the compressor 7 and to the inlet of the water condenser 15,

point 3p corresponds to the outlet of the water condenser 15 and to the inlet of the expansion member 14 associated with the third heat exchanger 13 in evaporator mode,

point 4p corresponds to the output of the expansion element 14 and to the inlet of the third heat exchanger 13 in evaporator mode,

point 5p corresponds to the output of the third heat exchanger 13 in evaporator mode and to the inlet of the second evaporator 11.

According to this air conditioning mode, from lp to 2 _P , the refrigerant is sucked by the compressor 7 and is compressed from a low pressure BP to a high pressure HP.

Thus, according to this mode of heat pump, the air conditioning system 1 is controlled so that the refrigerant circulates from the compressor 7 to the water condenser 15.

From 2 _P to 3p on the Mollier diagram, passing through the water condenser 15, the refrigerant fluid in the gaseous state compressed at high pressure HP, high temperature, gives up heat to the coolant.

The coolant having yielded heat to the coolant in the water condenser 15 leaves the water condenser 15 and is stored in the storage bottle 16.

The refrigerant then flows from the storage bottle 16 to the expansion device 14 upstream of the third heat exchanger 13 and undergoes isenthalpic expansion, 3p to _P 4 on Mo Yesterday diagram.

From 4p to 5p, the refrigerant passes through the third heat exchanger 13 working as an evaporator. By evaporating, the refrigerant absorbs the heat of the outside air flow FE passing through the third heat exchanger 13. The third heat exchanger 13 working in the evaporator thus allows the recovery of energy from the outside air flow FE. The refrigerant fluid at the outlet of the water condenser is therefore not forced to undergo subcooling in this third heat exchanger 13; subcooling that would degrade heat pump performance.

The coolant at the outlet of the third heat exchanger 13 then flows towards the connection point 23 to be directed towards the first evaporator 9.

From 5p to lp, the refrigerant undergoes a second evaporation at the first evaporator 9.

This makes it possible to recover a sufficient energy added to the energy of the compressor 7 to heat the coolant at the water condenser 15 and to improve the energy supplied to the heating radiator 25 to heat the air flow to the cockpit.

The refrigerant then leaves the first evaporator 9 and returns to the compressor 7 to restart a refrigerant cycle. With regard to the heat transfer fluid, the latter is for example movement by the pump 29 and passes through the water condenser 15, wherein the coolant absorbs the heat of the coolant.

The heat transfer fluid then passes through the heating radiator 25, where it transfers calories to the flow of air to the passenger compartment passing through it.

In this case, it is called indirect system, because the heating of the air flow to the passenger compartment is performed via the coolant circulating in the coolant circuit 5 and not directly by the refrigerant.

The flow of air to the destination may further pass through an additional heat exchanger for heating on the air 37 arranged downstream of the heating radiator 25 in the direction of flow of the air flow to be heated again.

By reaching the passenger compartment of the vehicle, for example under the action of a blower (not shown), the heated air flow makes it possible to increase the air temperature of the passenger compartment.

The coolant then leaves the heating radiator 25 to be directed back to the water condenser 15, possibly being circulated by the pump 29.

Second mode of heat pump

With reference to FIGS. 4a and 4b, a second mode of heat pump is described.

This second mode of heat pump differs from the first heat pump mode described with reference to FIGS. 3a and 3b, in that the refrigerant after expansion and first evaporation in the third heat exchanger 13 undergoes a new expansion. passing through the expansion member 17 upstream of the first evaporator 9 before being evaporated again within the first evaporator 9.

FIG. 4b is a diagrammatic representation of a cycle of the refrigerating fluid when the air conditioning system 1 is driven according to this second mode of heat pump, with the abscissa the enthalpy H kJ / kg and in ordinate the pressure P in Bars. The difference with the Mollier diagram shown in FIG. 3b is that from 4p to 5p 'the refrigerant passes through the third heat exchanger 13 used as an evaporator and being at a first pressure P1. At the outlet of the third heat exchanger 13, the fluid undergoes isenthalpic expansion through the expansion member 17 upstream of the first evaporator 9. From 5p 'to 1 _P , the refrigerant passes through the first evaporator 9 and undergoes a evaporation. The coolant is at a second pressure P2 lower than the first P1. The refrigerant then arrives at the compressor 7.

The fact of having two pressures PI, P2 is useful for example at low outside temperature. Indeed, when the outside temperature drops below a threshold temperature, for example of the order of 2 ° C, there is a risk of icing at the evaporator 9 of the front panel. In order to prevent frost from settling on the third heat exchanger 13, the detent 17 is slaved upstream of the first evaporator 9 so that the temperature of the third heat exchanger 13 is not lower than the dew point temperature.

The coolant circuit remains unchanged from the first heat pump mode described above. First mode of dehumidification

With reference to FIG. 5, the control of the air conditioning system 1 is now described according to a first dehumidification mode making it possible to dehumidify the flow of air to the passenger compartment by cooling it before this air flow does not cross the heating radiator 25 of the coolant circuit 5 to be heated.

To do this, the refrigerant fluid in the form of hot gas high pressure and high temperature at the outlet of the compressor 7 enters the water condenser 15, so as to heat the coolant circulating in the coolant circuit 5. In effect, in the water condenser 15, the coolant transfers heat to the coolant. The heated heat transfer fluid returns to the heating radiator 25. Beforehand, the coolant can circulate in an additional electrical heat exchanger (not shown) for example upstream of the heating radiator 25.

The coolant in turn after condensation in the water condenser 15 is directed to the third heat exchanger 13 acting as an evaporator undergoing an upstream expansion through the expansion member 14.

By evaporating, the refrigerant absorbs the heat of the outside air flow FE passing through the third heat exchanger 13. The third heat exchanger 13 working as an evaporator thus makes it possible to recover energy from the outside air flow FE. The refrigerant fluid at the outlet of the water condenser is therefore not forced to undergo subcooling in this third heat exchanger 13.

The coolant at the outlet of the third heat exchanger 13 then flows towards the connection point 23 to be directed both towards the first evaporator 9, in which the refrigerant while evaporating again recovers energy from the flow of outside air FE through the first evaporator 9, and to the second evaporator 11, wherein the refrigerant while evaporating recovers energy from the air flow to the passenger compartment.

This makes it possible to recover energy both on the front face within the third heat exchanger 13 and the first evaporator 9 and inside the air-conditioning and heating system within the second evaporator 11.

In addition, the flow of air to the passenger compartment passing through the second evaporator 11 is cooled and thus dehumidified before passing through the heating radiator 25, to be heated before opening into the passenger compartment.

The flow of air to the passenger compartment can possibly pass through the additional heating heat exchanger on the air 37 downstream of the heating radiator 25 in the direction of flow of the air flow to be heated from new.

The refrigerant at the outlet of the first evaporator 9 and the refrigerant at the outlet of the second evaporator 11 meet at the connection point 21 of the refrigerant circuit 3 upstream of the compressor 7 to then return to the compressor 7 and start a refrigerant cycle. This first mode dehumidiflcation can be interesting especially for a cold outdoor temperature, for example of the order of 5 ° C, requiring a high heating need with a low need for dehumidification.

Indeed, the energy stored at the three evaporators 9, 11, and 13 added to that of the compressor 7 sufficiently heat the coolant at the water condenser 15 and this energy is injected into the heating radiator 25 via the heat transfer fluid heated.

The first mode of dehumidification as described above is advantageously implemented in an electric vehicle mode.

Second mode of dehumidification

A second dehumidiflcation mode for dehumidifying the flow of air to the passenger compartment is shown schematically in Figure 6a.

This second mode of dehumidification differs from the first mode of dehumidification in that the refrigerant, after having circulated in the third heat exchanger 13 working in an evaporator, is directed only towards the second evaporator 11 and no longer towards the first evaporator 9. front face.

The refrigerant can then return to the compressor 7 to restart a refrigerant cycle.

The heat transfer fluid circuit 5 is similar to the first mode of dehumidification.

Is schematically represented in Figure 6b Mo a diagram of a first example Yesterday refrigerant cycle _D2 1, _D2 2, 3D _2, 4 _D2, 5D _2, when the air conditioning system 1 is driven according to this second dehumidification mode, with the abscissa enthalpy H in kJ / kg and the ordinate the pressure P in Bars.

On this first diagram of Mo Hier shown in Figure 6b, schematically and in terms of thermodynamics: point 1 _D2 corresponds to the output of the second evaporator 11 and to the inlet of the compressor 7,

point 2 _D2 corresponds to the output of the compressor 7 and to the inlet of the water condenser 15,

the point 3m corresponds to the outlet of the water condenser 15 and to the inlet of the expansion member 14 associated with the third heat exchanger 13 in evaporator mode,

point 4 _D2 corresponds to the output of the expansion element 14 and to the inlet of the third heat exchanger 13 in evaporator mode,

the point 5D ₂ corresponds to the output of the third heat exchanger 13 in evaporator mode and to the inlet of the second evaporator 11,

In this first example, the refrigerant does not undergo any further expansion before circulating in the second evaporator 11. To do this, the expansion member 19 can be completely open so that the refrigerant flowing through it does not undergo relaxation.

The refrigerant cycle is as follows:

- From 1D ₂ to 2 _D2 : the refrigerant is sucked by the compressor 7. The refrigerant is compressed from a low pressure BP to a high pressure HP,

from 2 _D2 to 3D ₂ : the refrigerant passes through the water condenser 15 and undergoes condensation until saturation,

- 3D _2-4 _D2: the refrigerant passes through the expansion device 14 and undergoes isenthalpic expansion,

from 4 _D2 to 5D ₂ : the refrigerant passes through the third heat exchanger 13 used as an evaporator,

- From 5D ₂ to 1 _D2 : the refrigerant passes through the second evaporator 11 without undergoing expansion beforehand and undergoes evaporation.

Is schematically represented in Figure 6c a Mollier diagram of a second exemplary refrigerant cycle _D2 1, _D2 2, 3D _2, 4 _'D2, 5'D ₂ 6'D _2, when the system The air conditioning unit 1 is controlled according to this second mode of dehumidification, with the abscissa enthalpy H in kJ / kg and the ordinate the pressure P in Bars. This second example differs from the first example of FIG. 6b in that the cooling fluid after expansion and evaporation in the third heat exchanger 13 undergoes a new expansion which lowers its pressure and temperature before passing into the second evaporator 11.

On this second diagram of Mo Hier illustrated in Figure 6c, schematically and in terms of thermodynamics:

point 1 _D2 corresponds to the output of the second evaporator 11 and to the inlet of the compressor 7,

the point 3D ₂ corresponds to the outlet of the water condenser 15 and to the inlet of the expansion member 14 associated with the third heat exchanger 13 in evaporator mode,

point 4 ' _D2 corresponds to the output of the expansion element 14 and to the inlet of the third heat exchanger 13 in evaporator mode,

the point 5'D ₂ corresponds to the output of the third heat exchanger 13 in evaporator mode and to the inlet of the expansion device 19 upstream of the second evaporator 11, and

point 6'D ₂ corresponds to the output of the expansion member 19 and to the inlet of the second evaporator 11,

The refrigerant cycle is as follows:

- from 3D ₂ to 4 ' _D2 : the coolant passes through the expansion member 14 and undergoes isenthalpic expansion,

- From 4 ' _D2 to 5'D ₂ : the refrigerant passes through the third heat exchanger 13 used as an evaporator. The third heat exchanger 13 is at a first pressure PI ',

from 5'D ₂ to 6'D ₂ : at the outlet of the third heat exchanger 13, the refrigerant undergoes a new isenthalpic expansion passing through the expansion member 19 upstream of the second evaporator 11, which lowers the pressure of the refrigerant at a second pressure P2 'lower than the first pressure PI', and

- From 6'D2 to 1 _D 2, the refrigerant passes through the second evaporator and undergoes a new evaporation. The refrigerant then arrives at the compressor 7.

For this second mode of dehumidification, the third heat exchanger 13 is used as an evaporator. The pressure of the third heat exchanger is higher or lower so that it exchanges more or less with the outside. Thus, to recover more or less energy from the outside, it plays on the trigger upstream of the second evaporator 11 to vary the pressure of the third heat exchanger 13. The pressure of the third heat exchanger 13 is higher and less energy is recovered from the outside, and conversely the pressure of the third heat exchanger 13 is high and the more energy is recovered from the outside.

This second mode of dehumidification is used, for example, for outside air temperatures of around 10 ° C.

Similarly to the first mode of dehumidification, the second dehumidification mode described above is advantageously implemented in an electric vehicle mode.

Third mode of dehumidification

Referring to Figures 7a, 7b, 7c there is described a third mode of dehumidification.

According to this third mode of dehumidification, the coolant after circulating in the water condenser 15 is directed to the third heat exchanger working this time in external subcooling heat exchanger 13 and no longer an evaporator.

The refrigerant flowing through the external subcooling exchanger 13 undergoes subcooling by heat exchange with the outside air flow FE before being directed towards the second evaporator 11. The energy is thus discharged to the outside. May be provided or not an expansion upstream of the third heat exchanger 13 through the expansion member 14.

The subcooled refrigerant flowing towards the second evaporator exchanger 11 undergoes an upstream expansion through the expansion member 19 which lowers its pressure and temperature before passing into the second evaporator 11. The refrigerant then evaporates. by absorbing the heat of the air flow to the passenger compartment that passes through it. The flow of air to the passenger compartment passing through the second evaporator 11 is thus cooled and thus dehumidified before opening into the passenger compartment.

The refrigerant fluid at the outlet of the second evaporator 11 can then return to the compressor 7 to restart a refrigerant cycle.

Thus, according to the first example of FIG. 7b without expansion before the subcooling of the coolant, the cycle of the refrigerant fluid is as follows:

from 1 _D3 to 2 _D3 : the refrigerant is sucked by the compressor 7 and compressed from a low pressure BP to a high pressure HP,

- from 2 _D3 to 3 _D3 : the refrigerant passes through the water condenser and undergoes condensation until saturation,

- From 3D3 to 4 _D3 : the refrigerant passes through the third heat exchanger working sub-cooling exchanger. The refrigerant fluid undergoes a forced subcooling or "subcooling" in English,

- From 4 _D3 to 5 _D3 : the refrigerant passes through the expansion member 19 upstream of the second evaporator 11 and undergoes isenthalpic expansion,

- From 5 _D3 to 1 _D3 : the refrigerant passes through the internal evaporator 11, namely the second evaporator 11, and undergoes evaporation. The refrigerant then returns to the compressor 7.

According to the second example of FIG. 7c with an expansion of the subcooling of the refrigerant, the cycle of the refrigerant fluid is as follows:

from 1 _D3 to 2 _D3 : the refrigerant is sucked by the compressor 7 and compressed from a low pressure BP to a high pressure HP, - From 2 _D3 to 3D3: the refrigerant passes through the water condenser 15 and undergoes condensation until saturation at a first pressure Pa,

from 3D3 to 4'D3: the refrigerant passes through the expansion element 14 upstream of the third heat exchanger 13 and undergoes isenthalpic expansion,

- From 4'D3 to 5'D3: the refrigerant passes through the third heat exchanger 13 working sub-cooling exchanger or "subcooler". The third heat exchanger 13 is at a second pressure Pb lower than the first pressure Pa,

from 5'D3 to 6'D3: at the outlet of the third heat exchanger 13 in subcooling exchanger mode, the refrigerant fluid undergoes isenthalpic expansion by passing through the expansion element 19 upstream of the second evaporator 11,

- From 6'D3 to 1 _D3 : the refrigerant passes through the internal evaporator 11 also called second evaporator 11 and undergoes evaporation. The refrigerant then arrives at the compressor 7.

For this third mode of dehumidification, the third heat exchanger is used as a subcooling exchanger.

A slight expansion can be added before the third heat exchanger 13 working sub-cooling exchanger to vary the pressure of the latter. The variation of the pressure of this subcooling exchanger 13 allows more or less energy exchange with the outside to reduce more or less the heating of the passenger compartment.

This third mode of dehumidification can be interesting in particular to meet a strong need for dehumidification and a low need for heating, for example for an outside temperature of about 15 ° C.

The third mode of dehumidification described above is also implemented in an electric vehicle mode. Fourth mode of dehumidification for a vehicle comprising a heat engine FIG. 8 represents another dehumidification mode adapted for an air conditioning system Γ of a heating, ventilation and / or air conditioning system for a motor vehicle comprising a heat engine 40.

The air conditioning system Γ is similar to the air conditioning system 1 described previously. According to this variant, the coolant circuit 5 of the air conditioning system 1 'further comprises a loop 6 for circulating the coolant between the heating radiator 25 and the heat engine 40. The coolant is optionally circulated in the loop 6 by a pump 41.

The fourth dehumidification mode makes it possible to dehumidify the flow of air to the passenger compartment by cooling it before heating it within the heating radiator 25 and recovering heat from the heat engine 40 by circulating the coolant 5. Thus, according to the fourth mode of dehumidification, as regards the coolant, the latter is for example set in motion by the pump 29 and passes through the water condenser 15 in which the heat transfer fluid absorbs the heat of the coolant.

The cooling radiator 27 is used to cool the heat transfer fluid from the water condenser 15 by heat exchange with the outside air flow FE.

The cooling radiator 27 further has an outlet through which the cooled heat transfer fluid leaves the cooling radiator 27 to be directed back to the water condenser 15, possibly being circulated by the pump 29. By cooling the heat transfer fluid, the cooling radiator 27 thus makes it possible to cool the water condenser 15.

In addition, the heat transfer fluid can be set in motion in the loop 6 for example by the pump 41 and circulate between the heat engine 40 and the heating radiator 25. Thus, the heat transfer fluid is heated thanks to the thermal losses of the heat engine 40 .

As regards the coolant, it is sucked by the compressor 7 and is compressed from a low pressure BP to a high pressure HP.

Then, the coolant flows from the compressor 7 to the water condenser 15.

By passing through the water condenser 15, the refrigerant fluid in the gaseous state compressed at high pressure HP, high temperature, gives up heat to the coolant circulating in the coolant circuit 5. The heated heat transfer fluid returns to the radiator of cooling 27 as explained above.

As for the refrigerant, it leaves the water condenser 15 and flows from the storage bottle 16 to the third heat exchanger 13 acting as an external subcooling exchanger 13, for a subcooling of the cooling fluid by heat exchange with the flow outside air FE. This allows the evacuation of calories to the outside.

In this case, the coolant does not undergo prior expansion by passing through the expansion member 14.

The cooling fluid subcooled after condensation is then directed for example to the connection point 23 connected to the output of the third heat exchanger and to the inlet of the first and second heat exchangers 9, 11. The refrigerant is then directed to the second expansion member 19 and undergoes isenthalpic expansion and then flows into the second evaporator 11.

During the passage in the second evaporator 11, the cooling fluid while evaporating absorbs the heat of the air flow through the second evaporator 11 to the passenger compartment.

The flow of air to the passenger compartment passing through the second evaporator 11 is thereby cooled and therefore dehumidified before passing through the heating radiator 25 in which circulates the heat transfer fluid heated by the engine 40, to be heated before opening into the passenger compartment.

The refrigerant then leaves the second evaporator 11 and returns to the compressor 7 to restart a refrigerant cycle, for example through the connection point 21 of the refrigerant circuit 3.

It is therefore understood that such an air conditioning system 1, Γ can be controlled with a subcooling of the refrigerant for example in air conditioning mode or certain dehumidification modes so as to benefit from the evacuation of calories to the room. which improves the performance, while being able to be driven, in particular to meet a heating need, using this exchanger not as a subcooling exchanger but as an evaporator so as not to lose calories to outside but instead absorbing calories from the outside.

Claims

1. A thermal air flow conditioning system for a motor vehicle comprising a refrigerant circuit (3) and a coolant circuit (5), said refrigerant circuit (3) comprising:

at least one first heat exchanger (9) arranged for a heat exchange between the refrigerant and an outside air flow (FE),

a second heat exchanger (11) arranged to condition a flow of air to the passenger compartment of said vehicle by heat exchange between the refrigerant and the air flow to the passenger compartment, and

- A water condenser (15) together with the coolant circuit (5) for a heat exchange between the coolant and the coolant, characterized in that:

- The refrigerant circuit (3) further comprises: "a third heat exchanger (13) arranged for a heat exchange between the refrigerant and the outside air flow (FE) and

An expansion element (14) arranged upstream of the third heat exchanger (13) in the direction of circulation of the refrigerant fluid and connected to the outlet of the water condenser (15), and in that - the third heat exchanger (13) ) is configured to work in a subcooling exchanger or an evaporator.

2. System according to claim 1, wherein the expansion member (14) upstream of the third heat exchanger (13) is configured for an expansion of the refrigerant fluid before evaporation of the refrigerant by heat exchange with the outside air flow. (FE) in the third heat exchanger (13), when the third heat exchanger (13) works as an evaporator. System according to one of the preceding claims, wherein the expansion member (14) upstream of the third heat exchanger (13) is configured for an expansion of the refrigerant fluid before subcooling the refrigerant by heat exchange with the flow of outside air (FE) within the third heat exchanger (13), when the third heat exchanger (13) operates in a subcooling exchanger.

System according to any one of the preceding claims, wherein the first heat exchanger (9) is arranged downstream of the third heat exchanger (13) in the direction of circulation of the refrigerant.

System according to any one of the preceding claims, wherein the second heat exchanger (11) is arranged downstream of the third heat exchanger (13) in the direction of circulation of the refrigerant.

System according to claims 4 and 5, wherein the second heat exchanger (11) is arranged for a circulation of refrigerant parallel to the flow of refrigerant in the first heat exchanger (9).

System according to any one of the preceding claims, in which the first heat exchanger (9) is a first evaporator and in which an expansion element (17) is arranged upstream of the first heat exchanger (9) in the direction of circulation of the refrigerant.

System according to any one of the preceding claims, in which the second heat exchanger (11) is a second evaporator and in which an expansion member (19) is arranged upstream of the second heat exchanger (11) in the direction of flow of the refrigerant.

System according to one of the preceding claims, wherein the heat transfer fluid circuit (5) comprises a heat exchanger (25) for heating the flow of air to the passenger compartment arranged downstream of the second heat exchanger (11) according to the flow direction of the air flow to the passenger compartment.

10. Heating, ventilation and / or air conditioning system characterized in that it comprises a thermal conditioning system (1,1 ') of an air stream according to any one of the preceding claims.