HVAC system for battery-powered electric vehicles, and battery-powered electric vehicles including it

Abstract

HVAC system for electric vehicle with traction battery, and electric vehicle with traction battery comprising thereon. The invention is an HVAC system (20) for an electric vehicle, comprising a thermodynamic generator (28) comprising: a first thermodynamic heating loop comprising successively a compressor (29), a heating heat exchanger (21) as a condenser, a heating expansion valve (31) and a front facade heat exchanger (23) as an evaporator; a second thermodynamic heating loop comprising successively the compressor (29), the heating heat exchanger (21) as a condenser, a second expansion valve (32) and an MCP heat storage device (30) as an evaporator;a thermodynamic PCM regeneration loop comprising successively the compressor (29), the PCM heat storage device (30) as condenser, the second expansion valve (32) and the front facade heat exchanger (23) as evaporator. Figure to be published with the abbreviation: Figure 2;

Description

Title of the invention: HVAC system for battery-powered traction electric vehicle, and battery-powered traction electric vehicle comprising therein

[0001] The present invention relates to the field of heating, ventilation and air conditioning (HVAC) systems, and in particular to an HVAC system for a battery traction electric vehicle, and to a battery traction electric vehicle comprising such an HVAC system.

[0002] A vehicle heating, ventilation and air conditioning (HVAC) system allows the temperature of the air coming from outside to be heated or cooled and distributed at the desired temperature to the various passengers of the vehicle by means of ventilation, which provides thermal comfort in the passenger compartment of the vehicle.

[0003] Recently, vehicle HVAC systems, and in particular heating systems, have had to evolve to adapt to vehicle electrification. Indeed, for internal combustion engines powered by gasoline or diesel, propulsion is provided by an internal combustion engine. Since the efficiency of an internal combustion engine is around 30% at best, this means that 70% of the energy produced by the combustion of gasoline or diesel is lost as heat through the exhaust and engine walls. Thus, by recovering this heat in the engine's cooling system, it can be used to provide heating for the passenger compartment. This is achieved by directing the heat-laden cooling water to an air-to-air heat exchanger, called a heater, located within the HVAC system. In this way, these readily available calories are used to heat the passenger compartment of the internal combustion vehicle without impacting its driving range.

[0004] With regard to battery-electric vehicles, which represent an increasingly large share of the French vehicle fleet, given the high efficiency of the powertrain, there is little energy loss in the form of heat. It is therefore not possible to utilize waste heat or to sufficiently heat the passenger compartment using the small amount of heat dissipated in the powertrain.

[0005] Heating devices such as positive temperature coefficient (PTC) electric heaters or heat pumps have therefore had to be installed in the HVAC systems of electric vehicles in order to generate this heat and provide heating for the passenger compartment. Since these PTC electric heaters and heat pumps are powered by the electric vehicle's traction battery to operate, there is a significant impact on the vehicle's range. The range of an electric vehicle depends on several factors, including the outside temperature, the heating setting requested by the user, and the vehicle's condition. However, it's important to note that heat pumps offer energy savings compared to PTC (Positive Temperature Coefficient) electric heaters because they utilize the heat present in the ambient air. Thus, for every 1 kW of electrical power consumed, a heat pump can typically provide up to 3 kW of heating, whereas PTC electric heaters only produce heat through the Joule effect, meaning they consume as much electrical energy as they produce heat, which significantly impacts the electric vehicle's range.

[0006] The trend among electric vehicle manufacturers is therefore to use a reversible heat pump to provide both heating and cooling for the vehicle's passenger compartment. Indeed, since vehicles are generally equipped with an air conditioning system, it is simply a matter of slightly modifying the thermodynamic loop to offer the possibility of reverse operation, namely a heat pump system. Such systems utilize the phase-change property of refrigerants to evaporate the fluid to absorb heat from a so-called "hot" source and condense the fluid to transfer heat to another so-called "cold" source. In the case of typical heat pump operation, the hot source is therefore the air outside the vehicle and the cold source is the air blown into the vehicle's passenger compartment.

[0007] Fig. 1 represents a conventional reversible heat pump 1 for an electric vehicle, which, in air conditioning mode, comprises a thermodynamic air conditioning loop successively including a compressor 2, a heating condenser 3, a solenoid valve 4 (controlled so as to bypass an expansion valve 5), an evaporator-condenser 6 located on the front of the electric vehicle and exchanging heat with the outside air 7, a solenoid valve 8 (controlled so as to pass through an expansion valve 9), the expansion valve 9 and an air conditioning evaporator 10. A recirculation flap 25 can be controlled to allow either outside air 52 or recycled air 53 from inside the passenger compartment of the electric vehicle to enter the ventilation ducts 12.The operation of the thermodynamic air conditioning loop is as follows: the expanded refrigerant received by the compressor 2 is compressed to heat it, then passes through the heating condenser 3 (a mixing flap 27 located upstream of the heating condenser 3 is then closed so that the passenger compartment of the electric vehicle does not receive hot air); the refrigerant then passes through the evaporator-condenser 6 (as a condenser) and liquefies; the refrigerant then arrives at the expansion valve 9 and is expanded to cool it; the refrigerant finally passes through the air conditioning evaporator 10 located in the ventilation ducts 12 of the passenger compartment of the electric vehicle and then returns to the compressor 2. The air conditioning evaporator 10 thus cools the air 52 or 53 which enters the ventilation ducts 12 and which is blown towards cabin nozzles (not visible on [Fig.l] and located downstream of the heating condenser 3) by means of a blower (or fan) (not visible on [Fig.l] and located upstream of the air conditioning evaporator 10).

[0008] In heating mode, the reversible heat pump 1 further comprises a thermodynamic heating loop successively including the compressor 2, the heating condenser 3, the solenoid valve 4 (controlled to pass through the expansion valve 5), the expansion valve 5, the evaporator-condenser 6 and the solenoid valve 8 (controlled to bypass the air conditioning evaporator 10). The operation of the thermodynamic heating loop is as follows: the expanded refrigerant received by the compressor 2 is compressed to heat it, then passes through the heating condenser 3 (the mixing flap 27 located upstream of the heating condenser 3 being then opened to heat the air 52 or 53 entering the ventilation ducts 12); the refrigerant then reaches the expansion valve 5 and is expanded to cool it; The refrigerant finally passes through the evaporator-condenser 6 (as an evaporator) and then returns to the compressor 2.The heating condenser 3 thus allows the air 52 or 53 which enters the ventilation ducts 12 to be heated and blown towards the passenger compartment nozzles via the blower.

[0009] A heating electric resistance 26 can be arranged downstream of the air conditioning evaporator 10 to heat the air exiting the air conditioning evaporator 10 when it is supplied with current.

[0010] These conventional heat pumps, however, have the drawback of suffering from degraded performance when used at low temperatures, which causes their coefficient of performance (COP), which represents the ratio between the heat energy produced by the heat pump and the electrical energy it consumes, to decrease significantly. Since the advantage of heat pumps lies precisely in having COPs greater than 1, it is very important to avoid this degraded operation. The weakness of existing heat pumps therefore lies in the temperature of the heat source (the outside air) that passes through the front-facing evaporator-condenser, which acts as the evaporator.When this temperature is too low, typically below -10°C, the COP reaches values ​​close to 1, meaning that the heat pump consumes almost as much electrical energy as it produces heat energy, which significantly impacts the electric vehicle's range.

[0011] The present invention aims to overcome the drawbacks of the prior art by proposing an HVAC system for electric vehicles, equipped with a generator thermodynamics including a phase change material (PCM) heat storage device which, in amplified operating mode, allows the front-facing heat exchanger of the electric vehicle to be replaced in order to improve the COP of the thermodynamic generator, the PCM heat storage device being able to be regenerated when the electric vehicle's traction battery is recharged at a charging station.

[0012] The present invention therefore has as its first object a heating, ventilation and air conditioning (HVAC) system for a battery-powered electric vehicle, comprising a heating heat exchanger for heating the air entering the passenger compartment of the electric vehicle and a front-facing heat exchanger configured to be located on the front of the electric vehicle and to exchange heat with the outside air; the HVAC system further comprising a thermodynamic generator having a heat pump function and comprising: a first thermodynamic heating loop comprising successively a compressor, the heating heat exchanger as a condenser, a heating expansion valve and the front-facing heat exchanger as an evaporator;characterized by the fact that the thermodynamic generator further comprises: a second thermodynamic heating loop comprising successively the compressor, the heating heat exchanger as a condenser, a second expansion valve and a phase change material (PCM) heat storage device as an evaporator; a thermodynamic loop for regenerating PCM into heat comprising successively the compressor, the PCM heat storage device as a condenser, the second expansion valve and the front facade heat exchanger as an evaporator; solenoid valves arranged in the various thermodynamic loops of the thermodynamic generator; and a computing circuit configured to control the solenoid valves so that the thermodynamic generator operates through only one of its three thermodynamic loops at a time;the calculation circuit is further configured to control the solenoid valves so that the thermodynamic generator operates via its thermodynamic loop of PCM regeneration into calories only when a charging of the electric vehicle's traction battery is detected at a charging station. ;

[0013] Thus, the calculation circuit of the HVAC system according to the first object of the present invention makes it possible to control the solenoid valves (which allow the refrigerant to circulate in the heat exchangers concerned) so that the thermodynamic generator operates in one of the following operating modes:

[0014] - a normal heat pump mode (via the first loop (thermodynamic heating) in which the front facade heat exchanger serves as an evaporator (with outside air as the heat source) and the heating heat exchanger (in the passenger compartment of the electric vehicle) serves as a condenser and allows the outside air entering the ventilation ducts of the passenger compartment of the electric vehicle to be heated;

[0015] - an amplified or "boosted" heat pump mode (via the second a thermodynamic heating loop) in which the MCP heat storage device acts as an evaporator (with the MCP as the heat source) and the heating heat exchanger (in the passenger compartment of the electric vehicle) acts as a condenser and allows the outside air entering the ventilation ducts of the passenger compartment of the electric vehicle to be heated; and

[0016] - a mode of regenerating MCP into calories (via the loop thermodynamics of MCP regeneration into calories) in which, only when the electric vehicle's traction battery is being charged at a charging station, the front-facing heat exchanger acts as an evaporator (with outside air as the hot source) and the MCP heat storage device acts as a condenser (with the MCP as the cold source), thereby regenerating calories (i.e., heating) the MCP of the MCP heat storage device.

[0017] In the second thermodynamic heating loop, called the heating amplification or "boost" loop, the heat source, initially the outside air in the first thermodynamic heating loop, is replaced by a PCM heated to a temperature higher than the phase change temperature. The PCM is positioned directly in the evaporator, which thus becomes a refrigerant / PCM heat exchanger. This facilitates the evaporation of the refrigerant because the PCM is at a much higher temperature than the outside air. Furthermore, a wide sensible heat range is possible because the refrigerant adjusts its evaporation temperature to achieve a positive temperature difference between the PCM and the refrigerant.

[0018] To meet the setpoint for the supply air from the HVAC system, the compressor speed can be regulated by a PID (Proportional, Integral, Derivative) controller. The input for this controller is the supply air temperature, which is compared to the setpoint to increase or decrease the compressor speed. In simpler terms, if the air temperature becomes too high, the compressor speed decreases, and if the air temperature becomes too low, the speed increases. This control system allows the entire HVAC system to adapt to the temperatures of the two sources, hot and cold, and to ensure evaporation and condensation in the relevant heat exchangers.

[0019] The compressor consumes more electricity when the compression ratio increases, which means there is a proportional relationship between the difference in The temperatures of the hot and cold sources and the compressor's electrical consumption were also considered. It was observed that the refrigerant's pressure and evaporation temperature are higher in the second heating loop (boost mode) than in the first heating loop (normal mode). Since the enthalpy diagram is bounded by the hot and cold source temperatures, and because the PCM is a high-temperature heat source, the work performed by the compressor is therefore less during operation of the second heating loop with heat passing through the PCM heat storage device. Consequently, for equivalent heating performance, the COP of the second heating loop is significantly higher (by a factor of eight) than that of the first heating loop.This result is also explained by the fact that the compressor operates at a higher efficiency point when the temperature difference between the two hot and cold sources is reduced.

[0020] It should be noted, however, that the thermodynamic generator in heat pump mode can only be boosted for a limited time, since the PCM is not an inexhaustible heat source. The boost effect will tend to diminish as the PCM temperature decreases. Indeed, when the thermodynamic generator uses the second thermodynamic heating loop, the PCM temperature gradually decreases as the evaporator extracts heat from it. The COP also decreases because the hot source (i.e., the PCM) sees its temperature decrease, thus making the evaporation process less and less efficient. The compressor speed must increase to compensate for the decrease in the hot source temperature and maintain the supply air temperature at the setpoint.The duration of the boost, i.e. the duration during which the heat pump can operate with a COP higher than the COP obtained by conventional heat pumps, can for example be about one hour.

[0021] To operate in boosted heat pump mode, the system needs to be recharged. This step involves heating the PCM to store heat and takes place during the electric vehicle's charging phase at a charging station. Since electricity availability is not a problem at this time, the electric vehicle's thermal management systems can be used to introduce heat into the PCM and return it to a liquid state. To do this, in the thermodynamic loop for regenerating the PCM into heat, the thermodynamic cycle is reversed so as to condense the refrigerant in the PCM heat storage device (which then becomes a PCM condenser) and evaporate it in the front-facing heat exchanger (which thus becomes an air evaporator). Since the electric vehicle is stationary, it is necessary to start the fan motor unit (FMV). This ensures airflow through the evaporator and absorbs heat from the outside air. Since condensation is an exothermic process, the refrigerant will transfer heat to the MCP, allowing it to return to a high temperature level before the next running cycle.

[0022] The present invention also relates to a second object of a heating, ventilation and air conditioning (HVAC) system for a battery-powered electric vehicle, comprising an air conditioning heat exchanger for air conditioning the air entering the passenger compartment of the electric vehicle and a front-facing heat exchanger configured to be located on the front of the electric vehicle and to exchange heat with the outside air; the HVAC system further comprising a thermodynamic generator having an air conditioning function and comprising: a first thermodynamic air conditioning loop comprising successively a compressor, the front-facing heat exchanger as a condenser, an air conditioning expansion valve and the air conditioning heat exchanger as an evaporator;characterized by the fact that the thermodynamic generator further comprises: a second thermodynamic air conditioning loop comprising successively the compressor, a phase change material (PCM) heat storage device as a condenser, a second expansion valve and the air conditioning heat exchanger as an evaporator; a thermodynamic PCM regeneration loop comprising successively the compressor, the front facade heat exchanger as a condenser, the second expansion valve and the PCM heat storage device as an evaporator; solenoid valves arranged in the various thermodynamic loops of the thermodynamic generator; and a computing circuit configured to control the solenoid valves so that the thermodynamic generator operates through only one of its three thermodynamic loops at a time;the calculation circuit is further configured to control the solenoid valves so that the thermodynamic generator operates via its thermodynamic loop for regenerating PCMs in frigories only when a charging of the electric vehicle's traction battery is detected at a charging station. ;

[0023] Thus, the calculation circuit of the HVAC system according to the second object of the present invention makes it possible to control the solenoid valves (which allow the refrigerant to circulate in the heat exchangers concerned) so that the thermodynamic generator operates in one of the following operating modes:

[0024] - a normal air conditioning mode (via the first loop thermodynamics of air conditioning) in which the front facade heat exchanger serves as a condenser (with outside air as the cold source) and the exchanger of The heat from the air conditioning (in the passenger compartment of the electric vehicle) acts as an evaporator and helps to cool the outside air entering the ventilation ducts of the passenger compartment of the electric vehicle;

[0025] - an amplified or "boosted" air conditioning mode (via the second a thermodynamic air conditioning loop) in which the MCP heat storage device acts as a condenser (with the MCP as the cold source) and the air conditioning heat exchanger (in the passenger compartment of the electric vehicle) acts as an evaporator and cools the outside air entering the ventilation ducts of the passenger compartment of the electric vehicle; and

[0026] - a mode of regeneration of MCP in frigories (via the loop thermodynamics of PCM regeneration in frigories) in which, only when the electric vehicle's traction battery is being charged at a charging station, the front-facing heat exchanger acts as a condenser (with outside air as the cold source) and the PCM heat storage device acts as an evaporator (with the PCM as the hot source), thereby regenerating (i.e., cooling) the PCM of the PCM heat storage device.

[0027] In the second thermodynamic air conditioning loop, called the amplification or "boost" loop, the cold source, initially the outside air in the first thermodynamic air conditioning loop, is replaced by a PCM. The PCM is positioned directly in the condenser, which thus becomes a refrigerant / PCM heat exchanger. This makes it easy to condense the refrigerant because the PCM is at a lower temperature than the outside air.

[0028] It should be noted, however, that the thermodynamic generator in air conditioning mode can only be boosted for a limited time, since the PCM is not an inexhaustible source of cooling. The boost effect will tend to diminish as the PCM temperature increases. Indeed, when the thermodynamic generator uses the second thermodynamic air conditioning loop, the PCM temperature gradually increases as the condenser extracts cooling from it.

[0029] To operate in boosted air conditioning mode, the system needs to be recharged. This step involves cooling the PCM to store cooling energy and takes place during the electric vehicle's charging phase at a charging station. Since electricity availability is not a problem at this time, the electric vehicle's thermal management systems can be used to introduce cooling energy into the PCM. To do this, in the PCM regeneration thermodynamic loop, the thermodynamic cycle is reversed so as to evaporate the refrigerant in the PCM heat storage device (which then becomes a PCM evaporator) and condense it in the front-facing heat exchanger (which thus becomes a (air-cooled condenser). Since the electric vehicle is stationary, it is necessary to start the cooling fan unit (CFU) to ensure airflow through the condenser and absorb cooling from the outside air. The refrigerant then transfers cooling to the MCP, allowing it to return to a low temperature level before the next driving cycle.

[0030] According to a particular feature of the first object of the invention, the HVAC system further comprises an air conditioning heat exchanger for air conditioning the air entering the passenger compartment of the electric vehicle; the thermodynamic generator of the HVAC system being a reversible heat pump and further comprising: a first thermodynamic air conditioning loop comprising successively the compressor, the heating heat exchanger, the front facade heat exchanger as a condenser, an air conditioning expansion valve and the air conditioning heat exchanger as an evaporator; a second thermodynamic air conditioning loop comprising successively the compressor, the MCP heat storage device as a condenser, the second expansion valve and the air conditioning heat exchanger as an evaporator;a thermodynamic regeneration loop for PCMs in frigories comprising successively the compressor, the heating heat exchanger, the front facade heat exchanger as condenser, the second expansion valve and the PCM heat storage device as evaporator; and solenoid valves arranged in the various thermodynamic loops of the reversible heat pump; the calculation circuit being configured to control the solenoid valves so that the reversible heat pump operates via only one of its six thermodynamic loops at a time; the calculation circuit being further configured to control the solenoid valves so that the reversible heat pump operates via one of its two PCM regeneration thermodynamic loops only when a charging of the electric vehicle's traction battery is detected at a charging station.

[0031] It should be noted that, in each of the first and second thermodynamic air conditioning loops, the heating heat exchanger is inactive, i.e. bypassed by the air blown into the ventilation system of the electric vehicle.

[0032] Thus, the reversible heat pump-type thermodynamic generator can operate either in heat pump mode to heat the air blown into the passenger compartment of the electric vehicle, or in air conditioning mode to cool the air blown into the passenger compartment of the electric vehicle. The HVAC system calculation circuit according to this embodiment of the present invention allows the solenoid valves (which allow the refrigerant to circulate in the heat exchangers) to be controlled. concerned) so that the thermodynamic generator operates in one of the following six operating modes:

[0033] - normal heat pump mode via the first loop heating thermodynamics (hot source: outside air; cold source: air blown into the ventilation ducts);

[0034] - Heat pump mode boosted via the second loop heating thermodynamics (hot source: PCM; cold source: air blown into the ventilation ducts);

[0035] - normal air conditioning mode via the first loop air conditioning thermodynamics (hot source: air blown into the ventilation ducts; cold source: outside air);

[0036] - air conditioning mode boosted via the second thermodynamic loop air conditioning (hot source: air blown into the MCP ventilation ducts; cold source: MCP);

[0037] - mode of regenerating MCP into calories via the loop Thermodynamics of PCM regeneration into calories (hot source: outside air; cold source: PCM); and

[0038] - mode of regeneration of MCP in frigories via the loop Thermodynamics of PCM regeneration in frigories (hot source: PCM; cold source: outside air).

[0039] The computing circuit may include at least one of a computer, a processor, a microprocessor, a microcontroller, a digital signal processor (DSP), or a programmable logic component of the field-programmable pre-diffused matrix (FPGA) or application-specific integrated circuit (ASIC) type, and memory.

[0040] According to a particular feature of the invention, the HVAC system further includes an outside temperature sensor, the calculation circuit being further configured, in the event of detection of a charging of the traction battery of the electric vehicle on a charging station, to control the solenoid valves so that the reversible heat pump operates by means of one or the other of its two thermodynamic loops of PCM regeneration according to the temperature detected by the outside temperature sensor.

[0041] Thus, when the traction battery is being recharged, the calculation circuit can use the temperature value measured by the outside temperature probe to determine whether the MCP should be regenerated in calories or frigories.

[0042] The calculation circuit could also make this choice by using today's date to determine which period of the year it corresponds to, and / or by using a temperature probe at the output of the MCP heat storage device.

[0043] According to a particular feature of the invention, the MCP heat storage device comprises a thermally insulated box containing at least one MCP, said box comprising a refrigerant inlet and a refrigerant outlet, said MCP heat storage device further comprising a tube snaking through at least one MCP inside the box between the refrigerant inlet and the refrigerant outlet, and a thermo-diffusing matrix disposed inside the box in contact with the tube.

[0044] Thus, at least one MCP is contained in a sealed manner inside the thermally insulated box.

[0045] The tube (or network of tubes) winds inside the box and ensures the circulation of the refrigerant between the refrigerant inlet and the refrigerant outlet of the box, and is also in direct contact with the thermo-diffusing matrix.

[0046] The thermo-diffusing matrix (for example, in the form of a set of fins or a honeycomb structure) allows the heat from the refrigerant to be diffused within at least one PCM, or vice versa.

[0047] According to a particular feature of the invention, each of the at least one PCM has a phase change temperature between -50°C and 300°C.

[0048] According to a particular feature of the invention, each of the at least one MCP is one of water, an organic paraffin-based MCP, an organic polyol-based MCP such as an erythritol-based MCP, an inorganic hydrated salt-based MCP and a metal-based inorganic MCP, or any combination thereof.

[0049] According to a particular feature of the invention, at least one MCP is pressurized inside the box, at a pressure greater than or equal to 100 kPa.

[0050] According to a particular feature of the invention, the box is made of plastic material, and the tube and the thermo-diffusing matrix are made of aluminum.

[0051] According to a particular feature of the invention, the box is thermally insulated using an insulating paint.

[0052] Thus, the insulating paint makes it possible to cover the entire box in order to minimize heat loss between at least one PCM and the outside.

[0053] According to a particular feature of the invention, the refrigerant circulating in the thermodynamic generator is one of 2,3,3,3-tetrafluoropropene (also called R-1234yf or HFO-1234yf), carbon dioxide (also called R-744), and 1,1,1,2-tetrafluoroethane (also called R-134a or HFC-134a).

[0054] According to a particular feature of the invention, the MCP heat storage device further comprises at least one electrical resistance positioned at contact of the thermo-diffusing matrix to allow for a recharge of calories to at least one MCP.

[0055] The refrigerants commonly used in automotive thermodynamic generators are either R-1234yf or R-744 (CO2). R-1234yf condenses at 90°C under a pressure of 31 bar, which means that, in the best-case scenario, it will be possible to recharge at least one PCM at a temperature of 90°C (if the compressor is capable of compressing the refrigerant to this pressure). R-744, on the other hand, condenses at a temperature of 30°C under a pressure of 72 bar, which means that this fluid cannot be used in its current state to recharge at least one PCM, except when operating in a supercritical state of the fluid. One of the PCMs that could be considered is erythritol because it has a very high latent heat. Since its phase change temperature is 118°C, it is therefore very difficult to return it to a liquid state during vehicle recharging using only refrigerant condensation.To overcome this drawback, one or more electrical resistors can be used, positioned in contact with the thermo-diffusing matrix to facilitate the recharging of at least one MCP with calories when the electrical resistors heat up.

[0056] According to a particular feature of the invention, the second thermodynamic heating loop further comprises, in parallel with the second expansion valve followed by the MCP heat storage device, an additional expansion valve followed by the front facade heat exchanger as an additional evaporator, the second thermodynamic heating loop further comprising, upstream of the second expansion valve and the additional expansion valve, a mixing solenoid valve configured to be controlled by the calculation circuit in order to distribute the refrigerant between the MCP heat storage device and the front facade heat exchanger according to the temperature of the refrigerant detected at the outlet of the MCP heat storage device.

[0057] In boosted heat pump mode, the refrigerant passes through the evaporator filled with a PCM at a high temperature (for example, 118°C for erythritol), which means that the refrigerant can reach very high temperatures (above 100°C). The refrigerant then enters the compressor with a very high superheat temperature, which can represent a potential risk to its operation. Indeed, compressors are partially cooled by the refrigerant itself. To overcome this drawback, a bypass of the PCM evaporator can be implemented, to circulate a portion of the refrigerant through the evaporator located at the front panel.

[0058] The second regulator and the additional regulator must be separate regulators because the operating pressure and temperature at the inlet of the two evaporators are not the same depending on whether it is the MCP evaporator or the front-facing air evaporator.

[0059] The mixing solenoid valve allows the distribution of flow rates to be controlled in each of the Two evaporators are used. Thus, when the PCM temperature is high, the majority of the refrigerant flow can circulate through the air-cooled evaporator. As the PCM temperature decreases, the refrigerant flow through the PCM evaporator can increase, ensuring that the refrigerant temperature at the compressor inlet does not exceed 3°C of superheat. By mixing the refrigerant from the PCM evaporator, which has a relatively high temperature, with the refrigerant from the air-cooled evaporator, which has a lower temperature, it is ensured that the refrigerant temperature at the compressor inlet does not damage the compressor.

[0060] According to a particular feature of the invention, the MCP heat storage device box contains a first compartment containing a first MCP, and a second compartment containing a second MCP different from the first MCP, the phase change temperature of the first MCP being different from the phase change temperature of the second MCP, the thermodiffusing matrix comprising a first part disposed in the first compartment and a second part disposed in the second compartment, the tube passing through, from the refrigerant inlet to the refrigerant outlet, the first and second compartments.

[0061] Ideally, the phase change temperature of the PCM should be lower than the average outdoor temperature in summer. However, since the PCM must also have a high phase change temperature for the boosted heat pump function, one solution is to use a box containing two different PCMs: one with a phase change temperature suitable for boosted heat pump mode (for example, around 50°C), and the other with a phase change temperature suitable for boosted cooling mode (for example, around 20°C). Each PCM is therefore sized to operate optimally "half the time." The resulting PCM heat storage device is said to be "bivalent" (i.e., capable of storing heat or cooling).

[0062] The two PCMs are integrated into two separate compartments to prevent them from mixing. It is very important to understand that thermal insulation from each other is unnecessary since they are heated to the same temperature by the refrigerant. The PCM heat storage device will be used in evaporator mode to extract heat from the PCMs in boosted heat pump mode, or to recharge the PCMs with cooling capacity in PCM regeneration mode. Conversely, the storage device MCP heat will be used in condenser mode to extract cooling from the MCPs in boosted air conditioning mode, or to recharge the MCPs with calories in MCP calorie regeneration mode.

[0063] According to a particular feature of the invention, the first MCP has a phase change temperature between -50°C and 30°C, and the second MCP has a phase change temperature between -10°C and 300°C, the phase change temperature of the first MCP being lower than that of the second MCP.

[0064] Thus, the first low-temperature PCM (for example, 20°C) can operate in sensible mode in summer and winter, and in latent mode in summer and winter. And the second high-temperature PCM (for example, 50°C) can operate in latent mode only in winter, and in sensible mode in summer and winter.

[0065] According to a particular feature of the invention, the HVAC system further comprises a water cooling device configured to cool the traction battery of the electric vehicle, said water cooling device being connected to the thermodynamic generator so as to enable the latter to recover the heat dissipated by the traction battery and recovered by the water cooling device.

[0066] It should be noted that the thermodynamic generator could also recover calories by recovering heat from the braking of the electric vehicle, by recovering calories dissipated by the power electronics of the electric vehicle and / or by recovering calories dissipated by the traction motor of the electric vehicle.

[0067] The present invention further relates to an electric vehicle with a traction battery, characterized by the fact that it is equipped with an HVAC system as described above.

[0068] To better illustrate the object of the present invention, a preferred embodiment will be described below, by way of illustration and not limitation, with reference to the attached drawings.

[0069] On these drawings:

[0070] [Fig. 1] is a schematic diagram of an HVAC system for an electric vehicle according to the prior art;

[0071] [Fig.2] is a schematic diagram of an HVAC system for an electric vehicle according to a preferred embodiment of the present invention;

[0072] [Fig.3] is a schematic diagram of the HVAC system according to the present invention operating via its first thermodynamic heating loop;

[0073] [Fig.4] is a schematic diagram of the HVAC system according to the present invention operating via its second thermodynamic heating loop;

[0074] [Fig.5] is a schematic diagram of the HVAC system according to the present invention operating via its thermodynamic loop for regenerating PCM into calories;

[0075] [Fig.6] is a schematic diagram of the HVAC system according to the present invention operating via its first thermodynamic air conditioning loop;

[0076] [Fig.7] is a schematic diagram of the HVAC system according to the present invention operating via its second thermodynamic air conditioning loop;

[0077] [Fig.8] is a schematic diagram of the HVAC system according to the present invention operating via its thermodynamic loop for regenerating PCMs in frigories;

[0078] [Fig.9] is a schematic cross-sectional view of a heat storage device MCP according to the present invention;

[0079] [Fig. 10] is a partial schematic diagram of the second thermodynamic heating loop according to a variant of the present invention;

[0080] [Fig. 11] is a schematic cross-sectional view of an MCP heat storage device according to a variant of the present invention;

[0081] [Fig. 12] is a diagram representing the operating temperatures as an example of the two PCMs of the PCM heat storage device of [Fig. 11]; and

[0082] [Fig. 13] represents an electric car equipped with the HVAC system according to the present invention and whose traction battery is being recharged on a charging station.

[0083] Referring to Figures 2 to 8, one can see that a heating, ventilation and air conditioning (HVAC) system 20 is shown therein according to a preferred embodiment of the present invention.

[0084] The HVAC system 20 according to the present invention is designed to be installed inside an electric vehicle 50 with a traction battery 51, as shown in [Fig. 13],

[0085] The HVAC system 20 includes a heating heat exchanger 21 for heating the air entering the passenger compartment of the electric vehicle 50, an air conditioning heat exchanger 22 for air conditioning the air entering the passenger compartment of the electric vehicle 50, and a front-facing heat exchanger 23 configured to be located on the front of the electric vehicle 50 and to exchange heat with the outside air 52.

[0086] The ventilation system 24 of the electric vehicle 50 comprises successively within its ventilation ducts, from the outside air intake to the ventilation nozzles inside the passenger compartment: a recirculation flap 25 (visible on [Fig.2]), the air conditioning heat exchanger 22, an electric heating element 26 (optional, and configured to heat the air exiting the air conditioning heat exchanger when it is powered), a mixing flap 27 and the heating heat exchanger 21.

[0087] It should be noted that a cabin air filter could also be positioned before the fan (or air blower) of the ventilation system 24, without departing from the scope of the present invention.

[0088] The recycling flap 25 can be controlled to allow either outside air 52 or recycled air 53 from inside the passenger compartment of the electric vehicle 50 to enter the ventilation ducts of the ventilation system 24. This recycling flap 25 has not been shown in Figures 3 to 8, in which it was assumed that only outside air entered the ventilation ducts of the ventilation system 24.

[0089] The mixing damper 27 can be controlled by the HVAC system 20's calculation circuit depending on whether the HVAC system 20 is operating in heating or cooling mode. In heating mode (as shown in Figures 3 and 4), the mixing damper 27 is controlled so that the air supplied (represented by the various arrows in the ventilation system 24) in the ventilation ducts passes through the heating heat exchanger 21. And, in cooling mode (as shown in Figures 6 and 7), the mixing damper 27 is controlled so that the air supplied in the ventilation ducts bypasses the heating heat exchanger 21.

[0090] The HVAC system 20 further includes a reversible heat pump type thermodynamic generator 28 comprising a compressor 29, the heating heat exchanger 21, the air conditioning heat exchanger 22, the front facade heat exchanger 23, a phase change material (PCM) heat storage device 30, three expansion valves 31, 32 and 33, four solenoid valves 34, 35, 36 and 37 controlled by the calculation circuit of the HVAC system 20, and various lines 38 for the circulation of a refrigerant fluid between the different elements of the thermodynamic generator 28.

[0091] The expansion valve 33 can, for example, be a thermostatic expansion valve.

[0092] Figures 3 to 8 respectively represent the six possible operating modes of the reversible heat pump-type thermodynamic generator 28 as a function of the control of the solenoid valves 34, 35, 36, and 37 by the HVAC system calculation circuit 20. In each of Figures 3 to 8, the elements of the thermodynamic generator 28 that are used in the particular operating mode illustrated are represented by solid lines, while the elements of the generator Thermodynamic components 28 that are not used in the illustrated particular operating mode are shown in dashed lines. In addition, in each of Figures 3 to 8, the inside of each pipe 38 of the thermodynamic generator 28 that is used in the illustrated particular operating mode is shown in black when the refrigerant flowing through it is in a compressed state (i.e., at high temperature), and in white when the refrigerant flowing through it is in an expanded state (i.e., at low temperature).

[0093] The refrigerant circulating in the thermodynamic generator 28 can be one of 2,3,3,3-tetrafluoropropene (also called R-1234yf or HFO-1234yf), carbon dioxide (also called R-744), and 1,1,1,2-tetrafluoroethane (also called R-134a or HFC-134a).

[0094] Each of the three solenoid valves 35, 36 and 37 are, for example, 3-way solenoid valves. The solenoid valve 34 can be either a 2-way solenoid valve or a 3-way solenoid valve.

[0095] The solenoid valve 34 is arranged in parallel with the pressure regulator 31 (which is arranged between the heating heat exchanger 21 and the front facade heat exchanger 23), and allows the refrigerant to either pass through or bypass the expansion valve 31.

[0096] The solenoid valve 35 is located downstream of the front facade heat exchanger 23, and allows the refrigerant from the front facade heat exchanger 23 to flow either to the compressor 29 or to the expansion valve 33 (which is located upstream of the air conditioning heat exchanger 22).

[0097] The solenoid valve 37 is disposed between the heat storage device MCP 30 and the compressor 29, and allows, when the heat storage device MCP 30 is used by the thermodynamic generator 28, the refrigerant to circulate either from the heat storage device MCP 30 to the inlet of the compressor 29, or from the outlet of the compressor 29 to the heat storage device MCP 30.

[0098] The solenoid valve 36 is located between the front facade heat exchanger 23 and the expansion valve 32 (which is connected to the heat storage device MCP 30 on the opposite side to the solenoid valve 37), and allows, when the heat storage device MCP 30 is used by the thermodynamic generator 28, to connect the expansion valve 32 either upstream or downstream of the front facade heat exchanger 23.

[0099] The reversible heat pump-type thermodynamic generator 28 can thus operate either in heat pump mode to heat the air blown into the passenger compartment of the electric vehicle 50, or in air conditioning mode to cool the air blown into the passenger compartment of the electric vehicle 50. The HVAC system calculation circuit 20 controls the various solenoid valves 34, 35, 36 and 37 (which circulate the refrigerant in the relevant heat exchangers) so that The thermodynamic generator 28 can operate in one of the following six operating modes:

[0100] - normal heat pump mode via the first loop heating thermodynamics illustrated in [Fig.3] (hot source: outside air; cold source: air blown into the ventilation ducts);

[0101] - Heat pump mode boosted via the second loop heating thermodynamics illustrated in [Fig.4] (hot source: PCM; cold source: air blown into the ventilation ducts);

[0102] - normal air conditioner mode via the first loop thermodynamics of air conditioning illustrated in [Fig.6] (hot source: air blown into the ventilation ducts; cold source: outside air);

[0103] - air conditioning mode boosted via the second thermodynamic loop air conditioning illustrated in [Fig.7] (hot source: air blown into the ventilation ducts; cold source: PCM);

[0104] - mode of regenerating MCP into calories via the loop Thermodynamics of PCM regeneration in calories illustrated in [Fig. 5] (hot source: outside air; cold source: PCM); and

[0105] - mode of regeneration of MCP in frigories via the loop Thermodynamics of PCM regeneration in frigories illustrated in [Fig.8] (hot source: PCM; cold source: outside air).

[0106] The MCP regeneration modes in calories or frigories are used by the thermodynamic generator 28 only when a charge of the traction battery 51 of the electric vehicle 50 is detected on a charging station 54 (as illustrated in [Fig. 13]).

[0107] As illustrated in [Fig.3], the first thermodynamic heating loop (normal heat pump mode) successively comprises the compressor 29, the heating heat exchanger 21 as a condenser, the expansion valve 31 called the heating expansion valve, the front facade heat exchanger 23 as an evaporator, and the solenoid valve 35. The front facade heat exchanger 23 thus serves as an evaporator (with outside air 52 as the heat source), and the heating heat exchanger 21 (in the ventilation system 24 of the electric vehicle 50) serves as a condenser and allows the outside air 52 entering the ventilation ducts of the ventilation system 24 of the electric vehicle 50 to be heated (given that the mixing flap 27 is controlled so that the blown air passes through the heating heat exchanger 21).

[0108] As illustrated in [Fig. 4], the second thermodynamic heating loop (boosted heat pump mode) comprises successively the compressor 29, the heating heat exchanger 21 as a condenser, the solenoid valve 34, the solenoid valve 36, the second expansion valve 32, the MCP heat storage device 30 as an evaporator, and the solenoid valve 37. The MCP heat storage device 30 thus serves as an evaporator (with the MCP as the heat source), and the heating heat exchanger 21 serves as a condenser and allows the outside air 52 entering the ventilation ducts of the ventilation system 24 of the electric vehicle 50 to be heated (given that the mixing flap 27 is controlled so that the blown air passes through the heating heat exchanger 21).

[0109] In the second thermodynamic heating loop, the heat source (initially the outside air 52 in the first thermodynamic heating loop) is thus replaced by a PCM brought to a temperature higher than the phase change temperature. The PCM is positioned directly in the evaporator, which therefore becomes a refrigerant / PCM heat exchanger. This makes it easy to evaporate the refrigerant because the PCM is at a much higher temperature than the outside air 52. Furthermore, a wide sensible heat range is possible because the refrigerant adjusts its evaporation temperature to obtain a positive temperature difference between the PCM and the refrigerant.

[0110] Since the compressor 29 operates at a better efficiency point when the difference between the temperatures of the two hot and cold sources is reduced, at equivalent heating performance, the COP of the second thermodynamic heating loop is significantly higher (by a factor of eight) compared to that of the first thermodynamic heating loop.

[0111] It should be noted, however, that the thermodynamic generator 28 in heat pump mode can only be boosted for a limited time, since the PCM is not an inexhaustible heat source. Indeed, when the thermodynamic generator 28 uses the second thermodynamic heating loop, the PCM temperature gradually decreases as the evaporator extracts heat from it. The COP also decreases because the heat source (i.e., the PCM) sees its temperature drop, thus making the evaporation process less and less efficient. The compressor speed must increase to compensate for the decrease in the heat source temperature and maintain the supply air temperature at the setpoint. Consequently, to operate again in boosted heat pump mode, the PCM heat storage device 30 of the HVAC system 20 needs to be recharged with heat.

[0112] As illustrated in [Fig. 5], the thermodynamic loop for regenerating PCM into calories (PCM regeneration mode into calories) successively comprises the compressor 29, the solenoid valve 37, the PCM heat storage device 30 as a condenser, the second expansion valve 32, the solenoid valve 36, the front facade heat exchanger 23 as an evaporator, and the solenoid valve 35. The exchanger The front facade heat 23 thus serves as an evaporator (with outside air 52 as the hot source), and the MCP 30 heat storage device serves as a condenser (with the MCP as the cold source), which allows the MCP of the MCP 30 heat storage device to be regenerated into calories (i.e., reheated).

[0113] This operating mode, which involves heating the PCM to store heat, occurs only during the charging phase of the electric vehicle 50 at the charging station 54. Since the availability of electricity is not a problem at this time, the thermal management systems of the electric vehicle 50 can be used to introduce heat into the PCM. To do this, in the thermodynamic loop for regenerating heat from the PCM, the thermodynamic cycle is reversed so as to condense the refrigerant in the heat storage device PCM 30 (which then becomes a PCM condenser) and evaporate it in the front-facing heat exchanger 23 (which thus becomes an air evaporator). Since the electric vehicle 50 is stationary, it is necessary to start the fan motor unit (FMV) to ensure airflow in the evaporator and absorb heat from the outside air 52.Since condensation is an exothermic process, the refrigerant will transfer heat to the MCP, allowing it to return to a high temperature level before the next running cycle.

[0114] As illustrated in [Fig.6], the first thermodynamic air conditioning loop (normal air conditioning mode) successively comprises the compressor 29, the heating heat exchanger 21, the solenoid valve 34, the front facade heat exchanger 23 as condenser, the solenoid valve 35, the expansion valve 33 called the air conditioning expansion valve, and the air conditioning heat exchanger 22 as evaporator. The front facade heat exchanger 23 thus serves as a condenser (with outside air 52 as the cold source), and the air conditioning heat exchanger 22 (in the ventilation system 24 of the electric vehicle 50) serves as an evaporator and allows the outside air 52 entering the ventilation ducts of the ventilation system 24 of the electric vehicle 50 to be cooled. The mixing flap 27 is controlled so that the blown air bypasses the heating heat exchanger 21 in order not to heat the blown air.

[0115] As illustrated in [Fig. 7], the second thermodynamic air conditioning loop (boosted air conditioning mode) comprises successively the compressor 29, the solenoid valve 37, the heat storage device MCP 30 as a condenser, the second expansion valve 32, the solenoid valve 36, the solenoid valve 35, the air conditioning expansion valve 33, and the air conditioning heat exchanger 22 as an evaporator. The heat storage device MCP 30 thus serves as a condenser (with the MCP as the cold source), and the air conditioning heat exchanger 22 serves as an evaporator and allows cool the outside air 52 entering the ventilation ducts of the ventilation system 24 of the electric vehicle 50.

[0116] In the second thermodynamic air conditioning loop, the cold source (initially the outside air 52 in the first thermodynamic air conditioning loop) is replaced by the PCM. The PCM is positioned directly in the condenser, which thus becomes a refrigerant / PCM heat exchanger. Therefore, it is easy to condense the refrigerant because the PCM is at a lower temperature than the outside air 52.

[0117] It should be noted, however, that the thermodynamic generator 28 in air conditioning mode can only be boosted for a limited time, since the MCP is not an inexhaustible source of cooling. Indeed, when the thermodynamic generator 28 uses the second thermodynamic air conditioning loop, the temperature of the MCP gradually increases as the condenser extracts cooling from it. Consequently, to operate again in boosted air conditioning mode, the heat storage device MCP 30 of the HVAC system 20 needs to be recharged with cooling.

[0118] As illustrated in [Fig.8], the thermodynamic loop for regenerating PCM in frigories (PCM regeneration mode in frigories) successively comprises the compressor 29, the heating heat exchanger 21, the solenoid valve 34, the front facade heat exchanger 23 as a condenser, the solenoid valve 36, the second expansion valve 32, the PCM heat storage device 30 as an evaporator, and the solenoid valve 37. The front facade heat exchanger 23 thus serves as a condenser (with outside air 52 as the cold source), and the PCM heat storage device 30 serves as an evaporator (with the PCM as the hot source), which allows the PCM of the PCM heat storage device 30 to be regenerated in frigories (i.e., cooled).

[0119] This operating mode, which involves cooling the PCM to store cooling energy, occurs only during the charging phase of the electric vehicle 50 at the charging station 54. Since the availability of electricity is not a problem at this time, the thermal management systems of the electric vehicle 50 can be used to introduce cooling energy into the PCM. To do this, in the thermodynamic loop for regenerating PCMs into cooling energy, the thermodynamic cycle is reversed so as to evaporate the refrigerant in the PCM heat storage device 30 (which then becomes a PCM evaporator) and condense it in the front-facing heat exchanger 23 (which thus becomes an air-cooled condenser). Since the electric vehicle is stationary, it is necessary to start the fan motor unit (FMV) to ensure airflow in the condenser and absorb the cooling energy from the outside air 52.The refrigerant then transfers cooling to the PCM, which... allows it to return to a low temperature level before the next driving cycle.

[0120] It should be noted that the thermodynamic generator 28 could also be limited to a heat pump function (in which case it would only include the three heating loops as illustrated in Figures 3 to 5) or to an air conditioner function (in which case it would only include the three air conditioning loops as illustrated in Figures 6 to 8), without departing from the scope of the present invention.

[0121] To meet the setpoint for the supply air at the outlet of the ventilation system 24 of the HVAC system 20, the rotational speed of the compressor 29 can be regulated by a PID (Proportional, Integral, Derivative) controller. The input for this controller is the supply air temperature, which is compared to the setpoint, in order to increase or decrease the compressor speed. This control system allows the entire HVAC system 20 to adapt to the temperatures of the two sources, hot and cold, and to ensure evaporation and condensation in the relevant heat exchangers.

[0122] The HVAC system 20 further includes an outside temperature sensor 40, the calculation circuit of the HVAC system 20 being further configured, in the event of detection of a charging of the traction battery 51 of the electric vehicle 50 on the charging station 54, to control the solenoid valves 34, 35, 36 and 37 so that the thermodynamic generator 28 operates by means of one or the other of its two thermodynamic loops of PCM regeneration (respectively illustrated in Figures 5 and 8) according to the temperature detected by the outside temperature sensor 40.

[0123] Thus, when the traction battery 51 is being recharged, the calculation circuit can use the temperature value measured by the outside temperature probe 40 to determine whether the MCP should be regenerated in calories or frigories.

[0124] The calculation circuit could further make this choice by using the current date to determine which time of year it corresponds to, and / or by using a temperature probe at the outlet of the MCP heat storage device 39. The HVAC system 20 may also include a water cooling device 41 (also called a "chiller") configured to cool the traction battery 51 of the electric vehicle 50 via a loop containing a water circuit 42 equipped with a pump 43, said water cooling device 41 being connected to the thermodynamic generator 28 upstream of the compressor 29 via an expansion valve 44 (for example, a thermostatic expansion valve), so as to allow the thermodynamic generator 28 to recover the heat dissipated by the traction battery 51 and recovered by the water cooling device 4L

[0125] It should be noted that the thermodynamic generator 28 could also recover calories by recovering heat from the braking of the electric vehicle 50, by recovering calories dissipated by the power electronics of the electric vehicle 50 and / or by recovering calories dissipated by the traction motor of the electric vehicle 50, without departing from the scope of the present invention.

[0126] Referring to [Fig.9], one can see that the MCP 30 heat storage device according to the present invention is represented there.

[0127] The MCP 30 heat storage device includes a box 60 containing at least one MCP 61.

[0128] The box 60 is thermally insulated by means of a thermal insulation 62 covering the entire box 60, so as to minimize heat loss between the at least one PCM 61 and the outside.

[0129] The thermal insulation 62 is preferably an insulating paint, but could also be any other type of insulation such as glass wool, rock wool or silica aerogel.

[0130] The heat storage device MCP 30 further includes a tube (or network of tubes) 63 snaking through at least one MCP 61 inside the box 60 between a refrigerant inlet 64a and a refrigerant outlet 64b formed on the box 60, the refrigerant inlet and outlet 64a and 64b providing for the connection of the heat storage device MCP 30 in the thermodynamic generator 28.

[0131] The MCP 30 heat storage device further includes a thermo-diffusing matrix 65 in the form of an array (or network) of fins arranged inside the box 30 in contact with the tube 63.

[0132] The thermo diffusing matrix 65 could also take the form of a honeycomb structure, without departing from the scope of the present invention.

[0133] The box 60 is made of plastic, while the tube 63 and the thermo-diffusing matrix 65 are made of aluminum or any other rigid thermally conductive material.

[0134] The fin assembly 65 of the thermo-diffusing matrix 65 allows the heat from the refrigerant to be diffused within at least one PCM 61, or vice versa.

[0135] Each of the at least one MCP 61 has a phase change temperature between -50°C and 300°C.

[0136] Each of the at least one MCP 61 may be one of the following: water, an organic paraffin-based MCP, an organic polyol-based MCP (for example, an erythritol or mannitol-based MCP), an inorganic hydrated salt-based MCP (for example example, RT111HC or HS78 or strontium hydroxide octahydrate) and a basic inorganic metal MCP, or any combination thereof.

[0137] At least one MCP 61 can be pressurized inside the box 60, at a pressure greater than or equal to 100 kPa.

[0138] Optionally, the heat storage device MCP 30 may also include an electrical resistance 66 snaking inside the box 60 and positioned in contact with the thermo-diffusing matrix 65, so as to facilitate the recharging of calories to at least one MCP 61 when an electric current passes through the electrical resistance 66 and the latter heats up.

[0139] In boosted heat pump mode (corresponding to the second thermodynamic heating loop illustrated in [Fig. 4]), the refrigerant passes through the evaporator (i.e., the heat storage device MCP 30) filled with a high-temperature MCP (e.g., 118°C for erythritol), which means that the refrigerant can reach very high temperatures (above 100°C). The refrigerant then enters the compressor 29 with a very high superheat temperature, which can represent a potential risk to its operation. To overcome this drawback, and as illustrated in [Fig. 10], a bypass of the evaporator with MCP 30 can be implemented, to circulate a portion of the refrigerant through the evaporator located on the front panel 23.

[0140] In this variant of the invention, the second thermodynamic heating loop comprises, in addition to the second expansion valve 32 followed by the heat storage device MCP 30, an additional expansion valve 67 followed by the front facade heat exchanger 23 as an additional evaporator, the second thermodynamic heating loop further comprising, upstream of the second expansion valve 32 and the additional expansion valve 67, a mixing solenoid valve 68 configured to be controlled by the calculation circuit of the HVAC system 20 in order to distribute the refrigerant between the heat storage device MCP 30 and the front facade heat exchanger 23 according to the temperature of the refrigerant detected at the outlet of the heat storage device MCP 30 by means of the temperature probe 39.

[0141] The second expansion valve 32 and the additional expansion valve 67 must be separate expansion valves because the operating pressure and temperature at the inlet of the two evaporators 30, 23 are not the same.

[0142] The mixing solenoid valve 68 controls the flow distribution in each of the two evaporators 30 and 23. Thus, when the PCM temperature is high, the majority of the refrigerant flow can circulate in the air evaporator 23. As the PCM temperature decreases, the refrigerant flow in the PCM evaporator 30 can increase, so that the fluid temperature The refrigerant temperature at the compressor inlet 29 does not exceed 3°C of superheat. By mixing the refrigerant from the PCM evaporator 30, which has a relatively high temperature, with the refrigerant from the air evaporator 23, which has a lower temperature, it is ensured that the temperature of the refrigerant at the compressor inlet 29 does not damage the compressor.

[0143] If we refer to [Fig. 11], we can see that the MCP 30 heat storage device is represented there according to a variant of the invention.

[0144] In this variant of the invention, the box 60 of the heat storage device MCP 30 contains a first compartment 60a containing a first MCP 61a, and a second compartment 60b containing a second MCP 61b different from the first MCP 61a, the phase change temperature of the first MCP 61a being different from the phase change temperature of the second MCP 61b.

[0145] It should be noted that the thermal insulator 62 and the thermo diffusing matrix 65 have not been shown on [Fig. 11], nor has the electrical resistance 66.

[0146] In this variant of the invention, the thermo diffusing matrix 65 comprises a first part (not shown in [Fig. 11]) disposed in the first compartment 60a and a second part (not shown in [Fig. 11]) disposed in the second compartment 60b.

[0147] The tube 63 passes, from the refrigerant inlet 64a to the refrigerant outlet 64b, through the first and second compartments 60a and 60b, winding between the two.

[0148] The first MCP 61a has a phase change temperature between -50°C and 30°C, while the second MCP 61b has a phase change temperature between -10°C and 300°C, the phase change temperature of the first MCP 61a being lower than that of the second MCP 61b.

[0149] Thus, the first MCP 61a at low temperature (for example, around 20°C) will be able to operate in sensitive mode in summer and winter, and in latent mode in summer and winter, while the second MCP 61b at high temperature (for example, around 50°C) will be able to operate in latent mode in winter only, and in sensitive mode in summer and winter.

[0150] Consequently, the second MCP 61b has a phase change temperature suitable for boosted heat pump mode (for example, around 50°C), and the first MCP 61a has a phase change temperature suitable for boosted cooling mode (for example, around 20°C). The MCP 30 heat storage device according to this variant is said to be "bivalent" (i.e., capable of storing either heat or cooling).

[0151] The two PCMs 61a and 61b are integrated into two separate compartments 60a and 60b to prevent them from being mixed up. Thermal insulation from each other is unnecessary since they are brought to the same temperature by the Refrigerant. The MCP 30 heat storage unit in this variant can be used in evaporator mode to extract heat from MCPs 61a and 61b in boosted heat pump mode, or to recharge MCPs 61a and 61b with cooling capacity in cooling capacity mode. Conversely, the MCP 30 heat storage unit in this variant can be used in condenser mode to extract cooling capacity from MCPs 61a and 61b in boosted air conditioning mode, or to recharge MCPs 61a and 61b with heat in cooling capacity mode.

[0152] Fig. 12 illustrates a diagram by way of example representing the operating temperatures of the two MCPs 61a and 61b of the MCP 30 heat storage device when the phase change temperature of the first MCP 61a is 20°C and the phase change temperature of the second MCP 61b is 50°C.

[0153] The temperature Tstorage>winter corresponds to the initial temperature of the two PCMs 61a and 61b before the running cycle in boosted heat pump mode. The temperature Tminjwinter corresponds to the temperature reached by the two PCMs 61a and 61b after the stored calories in these PCMs 61a and 61b used in boosted heat pump mode have been exhausted.

[0154] Similarly, the temperature Tstorage> summer corresponds to the initial temperature of the two PCMs 61a and 61b before the driving cycle with boosted air conditioning mode. Finally, the temperature TmaXjété indicates the maximum temperature reached by each of the PCMs 61a and 61b after the stored cooling capacity of these PCMs 61a and 61b used in boosted air conditioning mode has been exhausted.

[0155] In the "winter" operating range, i.e. the operating range in boosted heat pump mode, the two MCPs 61a and 61b contribute to the release of calories in the form of latent and sensible heat.

[0156] In the "summer" operating range, i.e., the operating range in boosted air conditioning mode, only the first MCP 61a operates optimally since the phase change temperature of the second MCP 61b will not be reached. However, the second MCP 61b will still be useful for discharging cooling in the form of solid sensible heat.

[0157] It is understood that the particular embodiment just described has been given by way of example and not limitation, and that modifications may be made without departing from the present invention.

Claims

1. Demands Heating, ventilation and air conditioning, HVAC, system, (20) for electric vehicle (50) with traction battery (51), comprising a heating heat exchanger (21) for heating the air entering the passenger compartment of the electric vehicle (50) and a front facade heat exchanger (23) configured to be arranged on the front facade of the electric vehicle (50) and to exchange heat with the outside air; the HVAC system (20) further comprising a thermodynamic generator (28) having a heat pump function and comprising: - a first thermodynamic heating loop comprising successively a compressor (29), the heating heat exchanger (21) as a condenser, a heating expansion valve (31) and the front facade heat exchanger (23) as an evaporator; characterized by the fact that the thermodynamic generator (28) further comprises: - a second thermodynamic heating loop comprising successively the compressor (29), the heating heat exchanger (21) as a condenser, a second expansion valve (32) and a phase change material heat storage device, PCM, (30) as an evaporator; - a thermodynamic loop for regenerating PCM into calories comprising successively the compressor (29), the PCM heat storage device (30) as condenser, the second expansion valve (32) and the front facade heat exchanger (23) as evaporator; - solenoid valves (34, 35, 36, 37) arranged in the different thermodynamic loops of the thermodynamic generator (28); and - a calculation circuit configured to control the solenoid valves (34, 35, 36, 37) so that the thermodynamic generator (28) operates through only one at a time of its three thermodynamic loops; the calculation circuit being further configured to control the solenoid valves (34, 35, 36, 37) so that the thermodynamic generator (28) operates via its loop

2. thermodynamics of regeneration of PCM in calories only in case of detection of a recharge of the traction battery (51) of the electric vehicle (50) on a charging station (54). Heating, ventilation and air conditioning (HVAC) system (20) for an electric vehicle (50) with a traction battery (51), comprising an air conditioning heat exchanger (22) for conditioning the air entering the passenger compartment of the electric vehicle (50) and a front-facing heat exchanger (23) configured to be located on the front of the electric vehicle (50) and to exchange heat with the outside air; the HVAC system (20) further comprising a thermodynamic generator (28) having an air conditioning function and comprising: - a first thermodynamic air conditioning loop comprising successively a compressor (29), the front facade heat exchanger (23) as a condenser, an air conditioning expansion valve (33) and the air conditioning heat exchanger (22) as an evaporator; characterized by the fact that the thermodynamic generator (28) further comprises: - a second thermodynamic air conditioning loop comprising successively the compressor (29), a phase change material heat storage device, PCM, (30) as condenser, a second expansion valve (32) and the air conditioning heat exchanger (22) as evaporator; - a thermodynamic loop for the regeneration of PCM in frigories comprising successively the compressor (29), the front facade heat exchanger (23) as condenser, the second expansion valve (32) and the PCM heat storage device (30) as evaporator; - solenoid valves (34, 35, 36, 37) arranged in the different thermodynamic loops of the thermodynamic generator (28); and - a calculation circuit configured to control the solenoid valves (34, 35, 36, 37) so that the thermodynamic generator (28) operates through only one at a time of its three thermodynamic loops; the calculation circuit being further configured to control the solenoid valves (34, 35, 36, 37) so that the thermodynamic generator (28) operates via its loop thermodynamics of regeneration of PCM in frigories only in case of detection of a recharge of the traction battery (51) of the electric vehicle (50) on a charging station (54).

3. HVAC system (20) according to claim 1, characterized in that it further comprises an air conditioning heat exchanger (22) for air conditioning the air entering the passenger compartment of the electric vehicle (50); the thermodynamic generator (28) of the HVAC system (20) being a reversible heat pump and further comprising: - a first thermodynamic air conditioning loop comprising successively the compressor (29), the heating heat exchanger (21), the front facade heat exchanger (23) as a condenser, an air conditioning expansion valve (33) and the air conditioning heat exchanger (22) as an evaporator; - a second thermodynamic air conditioning loop comprising successively the compressor (29), the MCP heat storage device (30) as a condenser, the second expansion valve (32) and the air conditioning heat exchanger (22) as an evaporator;- a thermodynamic regeneration loop of PCM in frigories comprising successively the compressor (29), the heating heat exchanger (21), the front facade heat exchanger (23) as condenser, the second expansion valve (32) and the PCM heat storage device (30) as evaporator; and - solenoid valves (34, 35, 36, 37) arranged in the different thermodynamic loops of the reversible heat pump; the calculation circuit being configured to control the solenoid valves (34, 35, 36, 37) so that the reversible heat pump operates through only one at a time of its six thermodynamic loops;the calculation circuit being further configured to control the solenoid valves (34, 35, 36, 37) so that the reversible heat pump operates via one of its two thermodynamic regeneration loops of PCM only when a charging of the traction battery (51) of the electric vehicle (50) is detected on a charging station (54).

4. HVAC system (20) according to claim 3, characterized in that it further comprises an outside temperature sensor (40), the calculation circuit being further configured, in the event of detection of a charging of the traction battery (51) of the electric vehicle (50) on a charging station (54), to control the solenoid valves (34, 35, 36, 37) so that the reversible heat pump operates by means of one or the other of its two thermodynamic regeneration loops of PCM depending on the temperature detected by the outside temperature sensor (40).

5. HVAC system (20) according to any one of claims 1 to 4, characterized in that the MCP heat storage device (30) comprises a thermally insulated box (60) containing at least one MCP (61; 61a, 61b), said box (60) comprising a refrigerant inlet (64a) and a refrigerant outlet (64b), said MCP heat storage device (30) further comprising a tube (63) snaking through the at least one MCP (61; 61a, 61b) inside the box (60) between the refrigerant inlet (64a) and the refrigerant outlet (64b), and a thermo-diffusing matrix (65) disposed inside the box (60) in contact with the tube (63).

6. HVAC system (20) according to claim 5, characterized in that each of at least one MCP (61; 61a, 61b) has a phase change temperature between -50°C and 300°C.

7. HVAC system (20) according to claim 5 or 6, characterized in that each of at least one MCP (61; 61a, 61b) is one of water, an organic paraffin-based MCP, an organic polyol-based MCP such as an erythritol-based MCP, an inorganic hydrated salt-based MCP and a metal-based inorganic MCP, or any combination thereof.

8. HVAC system (20) according to any one of claims 5 to 7, characterized in that at least one MCP (61; 61a, 61b) is pressurized inside the box (60) at a pressure greater than or equal to 100 kPa.

9. HVAC system (20) according to any one of claims 5 to 8, characterized in that the box (60) is made of plastic, and the tube (63) and the thermo-diffusing matrix (65) are made of aluminum.

10. HVAC system (20) according to any one of claims 5 to 9, characterized in that the box (60) is thermally insulated using an insulating paint.

11. HVAC system (20) according to any one of claims 5 to 10, characterized in that the MCP heat storage device (30) further comprises at least one electrical resistance (66) positioned in contact with the thermo-diffusing matrix (65) to allow a recharge of calories to at least one MCP (61; 61a, 61b).

12. HVAC system (20) according to claim 11 depending on claim 1, characterized in that the second thermodynamic heating loop further comprises, in parallel with the second expansion valve (32) followed by the MCP heat storage device (30), an additional expansion valve (67) followed by the front facade heat exchanger (23) as an additional evaporator, the second thermodynamic heating loop further comprising, upstream of the second expansion valve (32) and the additional expansion valve (67), a mixing solenoid valve (68) configured to be controlled by the calculation circuit in order to distribute the refrigerant between the MCP heat storage device (30) and the front facade heat exchanger (23) as a function of the temperature of the refrigerant detected at the outlet of the MCP heat storage device (30).

13. HVAC system (20) according to any one of claims 5 to 12, characterized in that the box (60) of the heat storage device MCP (30) contains a first compartment (60a) containing a first MCP (61a), and a second compartment (60b) containing a second MCP (61b) different from the first MCP (61a), the phase change temperature of the first MCP (61a) being different from the phase change temperature of the second MCP (61b), the thermo-diffusing matrix (65) comprising a first part disposed in the first compartment (60a) and a second part disposed in the second compartment (60b), the tube (63) passing, from the refrigerant inlet (64a) to the refrigerant outlet (64b), through the first and second compartments (60a, 60b).

14. HVAC system (20) according to claim 13, characterized in that the first PCM (61a) has a phase change temperature between -50°C and 30°C, and the second PCM (61b) has a phase change temperature between -10°C and 300°C, the phase change temperature of the first PCM (61a) being lower than that of the second PCM (61b).

15. HVAC system (20) according to any one of claims 1 to 14, characterized in that the refrigerant circulating in the thermodynamic generator (28) is one of 2,3,3,3-tetrafluoropropene, carbon dioxide, and 1,1,1,2-tetrafluoroethane.

16. HVAC system (20) according to any one of claims 1 to 15, characterized in that it further comprises a water cooling device (41) configured to cool the traction battery (51) of the electric vehicle (50), said water cooling device (41) being connected to the thermodynamic generator (28) so as to enable the latter to recover the heat dissipated by the traction battery (51) and recovered by the water cooling device (41).

17. Electric vehicle (50) with traction battery (51), characterized in that it is equipped with an HVAC system (20) according to any one of claims 1 to 16.

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