Thermal regulation system

Abstract

Title: Thermal Regulation System The invention relates to a thermal regulation system (1), in particular configured for installation on a vehicle, comprising: a refrigerant circuit (50) configured to use a refrigerant, in particular a flammable type, for example a hydrocarbon-based refrigerant, in particular propane; an enclosure (30) in which the refrigerant circuit (50) is placed, the enclosure being provided with sealed walls (31) and a vent (32) configured to allow the gas present in the enclosure to escape to the outside of the enclosure through this vent (32), in particular when the pressure in the enclosure reaches a predetermined pressure threshold associated with the vent. Figure for the abstract: Fig. 1

Description

Title of the invention: Thermal regulation system

[0001] The present invention relates to a thermal regulation system with a refrigerant circuit configured to use a refrigerant, in particular of a flammable type, for example a hydrocarbon type refrigerant, in particular propane (also referred to as R290 refrigerant).

[0002] Patent application JP29704297A (or JP11132595) describes a vehicle air conditioning system operating with a refrigeration cycle using a refrigerant such as propane. This patent application advocates for the detection of propane leaks.

[0003] The present invention aims to improve the safety of devices using a refrigerant, in particular of a flammable type, for example a hydrocarbon type refrigerant.

[0004] The invention thus relates to a thermal regulation system, in particular configured to be mounted on a vehicle, comprising: - a refrigerant circuit configured to use a refrigerant, including a flammable type, for example a hydrocarbon-based refrigerant, such as propane, - an enclosure in which the refrigerant circuit is placed, the enclosure being provided with sealed walls and a vent configured to allow the gas present in the enclosure to exit to the outside of the enclosure through this vent, in particular when the pressure in the enclosure reaches a predetermined pressure threshold associated with the vent.

[0005] The invention thus makes it possible to confine / encapsulate the refrigerant circuit within a sealed volume, thereby reducing the risk of refrigerant leaks (which can be dangerous in the case of flammable refrigerants). The enclosure also protects the refrigerant circuit, for example, mechanically (e.g., against shocks) and / or thermally (against a heat source). In general, the invention improves system safety.

[0006] The walls of the enclosure can for example be fireproofed and / or mechanically reinforced, for example using composite material.

[0007] According to one aspect of the invention, the vent is configured to, in particular depending on the pressure inside the enclosure, lower the pressure in the enclosure, in particular the vent being a valve configured to be able to open when the pressure reaches or exceeds the predetermined pressure threshold associated with the vent or the vent being a membrane configured to allow gas to pass through when the pressure reaches or exceeds the predetermined pressure threshold associated with the vent.

[0008] According to one aspect of the invention, the vent is configured to prevent a flame formed outside the enclosure from entering the enclosure through the vent.

[0009] According to one aspect of the invention, the thermal control system includes a safety system comprising a refrigerant leak detector, configured to detect a refrigerant leak from the refrigerant circuit, and the safety system is configured to interrupt the circulation of the refrigerant in the refrigerant circuit in the event of leak detection by the detector, in particular when the concentration of refrigerant outside the refrigerant circuit reaches or exceeds a predetermined concentration threshold or when the measured pressure reaches or exceeds a predetermined interruption pressure threshold.

[0010] According to one aspect of the invention, the safety system is configured to interrupt the circulation of the refrigerant in the refrigerant circuit by stopping a compressor of the refrigerant circuit.

[0011] According to one aspect of the invention, the refrigerant circuit is configured so that it can be segmented to obtain at least two refrigerant circuit segments that are isolated from each other when a refrigerant leak is detected.

[0012] According to one aspect of the invention, the refrigerant circuit includes one or more valves configured to segment the refrigerant circuit into different segments, including at least one expansion valve or an open closed expansion valve or an open expansion valve.

[0013] According to one aspect of the invention, the thermal regulation system comprises a hydrocarbon adsorption or absorption device configured to adsorb or absorb hydrocarbons present in the enclosure

[0014] According to one aspect of the invention, the enclosure contains an inert atmosphere for the refrigerant.

[0015] According to one aspect of the invention, the enclosure also receives, in addition to the refrigerant circuit, a heat transfer fluid circuit.

[0016] According to one aspect of the invention, the heat transfer fluid circuit includes an expansion vessel, and a refrigerant leak detector is preferably placed in the enclosure, in particular to detect the passage of refrigerant through a vent in the expansion vessel.

[0017] The invention further relates to a method for protecting a thermal regulation system comprising a refrigerant circuit using a refrigerant, in particular a flammable one, for example of the hydrocarbon type, in particular propane, the method comprising the following step: - Place the refrigerant circuit in an enclosure with sealed walls and a vent configured to allow the gas present in the enclosure to escape to the outside of the enclosure through this vent, particularly when the pressure inside the enclosure reaches a predetermined pressure threshold associated with the vent.

[0018] The invention also relates, independently or in combination with the foregoing, to a thermal regulation system, in particular configured to be mounted on a vehicle, comprising: - a refrigerant circuit configured to use a refrigerant, including a flammable type, for example a hydrocarbon-based refrigerant, such as propane, - a safety system configured to interrupt the circulation of refrigerant in the refrigerant circuit in the event of a risk of refrigerant leak.

[0019] Advantageously, the safety system includes a refrigerant leak detector, configured to detect a refrigerant leak from the refrigerant circuit, and the safety system is configured to interrupt the circulation of the refrigerant in the refrigerant circuit in the event of leak detection by the detector, in particular when, outside the refrigerant circuit, the refrigerant concentration reaches a predetermined concentration threshold or when the measured pressure reaches a predetermined interruption pressure threshold.

[0020] Advantageously, the thermal control system is configured to interrupt the refrigerant circulation in the refrigerant circuit if a leak is detected when the refrigerant concentration outside the refrigerant circuit reaches a predetermined concentration threshold or when the pressure measured outside the refrigerant circuit reaches a predetermined interruption pressure threshold. In other words, a leak is confirmed (referred to as a "leak detected" situation) when the refrigerant concentration outside the refrigerant circuit reaches a certain concentration threshold or when the pressure measured outside the refrigerant circuit reaches a certain predetermined interruption pressure threshold. These thresholds are called leak detection thresholds, which trigger the interruption of refrigerant circulation in the circuit.

[0021] The leak detection thresholds indicated above are chosen based on the lower explosive limit (LEL). The lower explosive limit (LEL) of a combustible gas or vapor designates the minimum concentration above which the substance can be ignited. The lower explosive limit (LEL) is expressed as a percentage (%) by volume in air. Below the lower explosive limit (LEL), the mixture is too lean in fuel to initiate any reaction. In one embodiment of the invention, the leak detection threshold, or concentration threshold, is less than or equal to 50% of the lower explosive limit (LEL) of propane, which is approximately 2.2% or 2.3%. For example, when the propane concentration reaches 1.1% (50% of 2.2%), a leak is considered present, and the safety system interrupts the refrigerant flow in the refrigerant circuit. An alarm trigger threshold (e.g., a visual or audible alarm) can be set below the leak detection threshold, or concentration threshold, for example, with a margin of 20%. In the given example, with a margin of 20%, the alarm trigger threshold could be 0.88% propane concentration (0.88% = 1, 1% * (1 - 20%)). Thus, an audible alarm can be triggered as soon as the propane concentration reaches 0.88%.

[0022] According to one aspect of the invention, the safety system is configured to interrupt the circulation of refrigerant in the refrigerant circuit by shutting down a compressor in the refrigerant circuit. This makes it possible to limit / slow down the refrigerant leak. Conversely, if the compressor continues to operate while a leak occurs, then the leak continues, or even intensifies, because the compressor continues to maintain refrigerant circulation.

[0023] According to one aspect of the invention, the refrigerant circuit is configured so that it can be segmented to obtain at least two refrigerant circuit segments that are isolated from each other when a refrigerant leak is detected.

[0024] Thus, in the event of a leak, the refrigerant, for example propane, cannot pass from one segment to another, so that if the leak involves one of the segments, the amount of refrigerant that leaks is limited to the amount of refrigerant present in that segment. The refrigerant contained in the other segment(s) remains trapped and cannot leak. This reduces the amount of refrigerant that leaks out of the refrigerant circuit.

[0025] According to one aspect of the invention, the refrigerant circuit comprises one or more valves configured to segment the refrigerant circuit into different segments.

[0026] According to one aspect of the invention, the number of valves is less than the number of segments, for example, being equal to the number of segments minus one. Alternatively, the number of valves is equal to the number of segments.

[0027] By closing the valve, it is possible to isolate two segments of the circuit on either side of this valve.

[0028] In particular, at least one of the segments is closed by two valves at two ends of this segment.

[0029] According to one aspect of the invention, the number of segments is chosen so that the mass of refrigerant in each segment is less than a predetermined mass value, in particular less than 150 g.

[0030] Thus, when the segments are isolated from each other, the mass of refrigerant that can leak is less than the predetermined mass value.

[0031] When the refrigerant is propane, each segment is configured to contain less than 150 g of refrigerant.

[0032] In another embodiment of the invention, for a refrigerant (named "a") that has a lower explosive limit LEL(a) and propane has an LEL of 2.2%, then the mass of refrigerant "a" in each segment is chosen to be less than (150*LEL(a) / 2.2%). The more explosive a refrigerant is (i.e., the lower the LEL value), the less refrigerant each segment must contain by mass.

[0033] For a total mass of refrigerant (propane) of 400 g, the number of segments is chosen to be 3 so that the mass in each segment is less than or equal to 150 g.

[0034] According to one aspect of the invention, the valve or valves used to segment the refrigerant circuit may include at least one expansion valve (or in English “Expansion valves” or EXV).

[0035] According to one aspect of the invention, the expansion valve is a closed open expansion valve (or in English “Closed expansion open valve” or CEO).

[0036] According to one aspect of the invention, the expansion valve is an open expansion valve (or in English “Open expansion valve” or CO).

[0037] According to one aspect of the invention, the leak detector comprises a sensor disposed outside the refrigerant circuit and configured to detect the presence of refrigerant.

[0038] According to one aspect of the invention, the sensor is a hydrocarbon sensor, in particular a propane sensor. This type of sensor allows for the direct detection of a leak, in particular by enabling the determination of a hydrocarbon concentration.

[0039] According to one aspect of the invention, the refrigerant circuit includes a refrigerant reservoir and the leak detector is configured to detect a drop in level in this refrigerant reservoir.

[0040] This detection is an indirect detection because the occurrence of a refrigerant leak appears as a consequence of the drop in level in this refrigerant reserve.

[0041] According to one aspect of the invention, the refrigerant circuit is placed in an enclosure.

[0042] According to one aspect of the invention, the enclosure is provided with sealed walls and a vent configured to allow the gas present in the enclosure to escape to the outside of the enclosure through this vent, particularly when the pressure in the enclosure reaches a predetermined pressure threshold associated with the vent. The predetermined interruption pressure threshold is the same as, or different from, the pressure threshold associated with the vent. In particular, the predetermined interruption pressure threshold is less than or equal to the pressure threshold associated with the vent.

[0043] According to one aspect of the invention, this vent is configured to be controlled, in particular according to the pressure inside the enclosure, in order to lower the pressure in the enclosure.

[0044] According to one aspect of the invention, the vent is a valve configured to be able to open when the pressure reaches the predetermined pressure threshold associated with the vent.

[0045] According to one aspect of the invention, the vent is a membrane configured to allow gas (which may then contain gaseous hydrocarbon) to pass through when the pressure reaches the predetermined pressure threshold associated with the vent.

[0046] According to one aspect of the invention, the vent is formed of porous bronze.

[0047] The vent is advantageously configured to prevent a flame formed outside the enclosure from entering the enclosure through the vent.

[0048] In particular, the vent is configured to prevent the flame from rising back into the enclosure, thus blocking flame propagation within the enclosure.

[0049] To this end, the vent is configured to have a maximum experimental safety gap (MESG) value, which is defined as the maximum thickness of the air layer between two parts of an internal chamber of a test apparatus that, when the internal mixture is ignited, prevents the ignition of the same external gas mixture through a shoulder of a given length. The MESG value is expressed in millimeters. In the present invention, for the case of propane, the vent is characterized by a ratio of hydraulic diameter divided by wall thickness (equivalent to the vent length) that is less than 3.6%.

[0050] According to one aspect of the invention, the thermal regulation system comprises a hydrocarbon adsorption or absorption device configured to adsorb or absorb hydrocarbons present in the enclosure. In particular, the hydrocarbon adsorption or absorption device is located within the enclosure.

[0051] According to one aspect of the invention, the activated carbon may be of reference RX 1.5, or CNR-115, or Cu-MOF-74 or Co-MOF-74.

[0052] Other usable activated carbons are for example those marketed under the name EcoSorb™.

[0053] According to one aspect of the invention, the enclosure contains an inert atmosphere for the hydrocarbon. The inert atmosphere contains nitrogen or argon, for example.

[0054] According to one aspect of the invention, the leak detector is placed in this enclosure.

[0055] In particular, when the leak detector includes a gas sensor, the gas sensor (for example propane) is placed inside this enclosure to detect a possible leak.

[0056] According to one aspect of the invention, the system is configured to deliver leak information, for example in the form of an audible or visual alarm, when the gas sensor detects a gas concentration in the interior space of the enclosure that reaches the predetermined concentration threshold, or alarm trigger threshold.

[0057] According to another aspect of the invention, the leak detector may include a pressure sensor, and optionally a temperature sensor in addition to the pressure sensor.

[0058] According to one aspect of the invention, the pressure sensor can be placed in the interior space of the enclosure and configured to measure the pressure in that enclosure.

[0059] This pressure sensor makes it possible to detect a possible refrigerant leak from the refrigerant circuit if the measured pressure reaches the predetermined interruption pressure threshold.

[0060] The pressure increase corresponds to an accumulation of gas (for example propane) in the enclosure.

[0061] Alternatively, the pressure sensor can be configured to measure the pressure in the refrigerant circuit. The pressure sensor is, in particular, placed in the refrigerant circuit.

[0062] This pressure sensor makes it possible to detect a possible refrigerant leak from the refrigerant circuit if the measured pressure falls below a predetermined internal pressure threshold.

[0063] The pressure drop corresponds to a leak of refrigerant (for example propane) outside the refrigerant circuit. The predetermined internal pressure threshold is defined according to the location of the sensor in the circuit (for example upstream or downstream of the compressor).

[0064] The volume of the enclosure is for example between 20 and 25 liters.

[0065] According to one aspect of the invention, the refrigerant circuit includes at least one compressor, in particular an electric compressor, for compressing the refrigerant and a condenser.

[0066] According to one aspect of the invention, the enclosure also receives, in addition to the refrigerant circuit, at least part of a heat transfer fluid circuit. The heat transfer fluid circuit may be partially located outside the enclosure.

[0067] In this case, the refrigerant circuit comprises, in addition to the compressor and the condenser, one or more two-fluid heat exchangers (also called "Chiller" in English), and the refrigerant circuit and the heat transfer fluid circuit are configured to exchange heat mutually, via the two-fluid heat exchanger(s). of the refrigerant circuit. The two-fluid heat exchanger(s) are notably located within the enclosure.

[0068] According to one aspect of the invention, the heat transfer fluid circuit includes a pump (in particular a water pump), an expansion vessel (or “surge tank”), and at least one single-way valve or a multi-way valve.

[0069] According to one aspect of the invention, the heat transfer fluid circuit includes an expansion vessel, and a refrigerant leak detector is preferably placed in the enclosure, near the expansion vessel of the heat transfer fluid circuit.

[0070] The heat transfer fluid circuit (in particular a water circuit) can be used to cool the passenger compartment (via an HVAC), and / or battery modules, and / or the electric motor, and / or electronic modules.

[0071] According to one aspect of the invention, the heat transfer fluid circuit uses a heat transfer fluid such as glycol water

[0072] According to one aspect of the invention, the expansion vessel (surge tank) makes it possible to balance the quantity of the heat transfer fluid in the heat transfer fluid circuit by making it possible to supply heat transfer fluid in case of deficit.

[0073] The refrigerant sensor is preferably placed in the enclosure, near a vent (degassing vent) of the expansion vessel (surge tank) of the heat transfer fluid circuit (water circuit).

[0074] According to one aspect of the invention, the vent defines a non-return valve.

[0075] According to one aspect of the invention, the refrigerant sensor is arranged to detect the passage of refrigerant through the vent of the expansion tank (surge tank).

[0076] According to one aspect of the invention, the refrigerant sensor is placed outside of the expansion tank (surge tank), and in particular the internal chamber which contains the refrigerant circuit and heat transfer fluid circuit.

[0077] Alternatively, the refrigerant sensor is placed inside the expansion tank (surge tank).

[0078] According to one aspect of the invention, the heat transfer fluid circuit is configured so that it can be segmented to obtain at least two heat transfer fluid circuit segments that are isolated from each other.

[0079] Indeed, the refrigerant can mix with the heat transfer fluid, in particular glycol water, and leaks can come from this heat transfer fluid circuit, in addition to the refrigerant circuit.

[0080] It may therefore be useful to provide for the possibility of segmenting not only the refrigerant circuit but also the heat transfer fluid circuit.

[0081] In another embodiment of the invention, the safety system is configured to interrupt the circulation of the refrigerant in the refrigerant circuit in the event of a vehicle accident or incident on the vehicle.

[0082] For example, in the event of an impact to the vehicle (an impact likely to damage the refrigerant circuit and cause a leak in that circuit), the safety system is configured to interrupt the refrigerant circulation in the refrigerant circuit. In this case, interrupting the refrigerant circulation in the circuit does not require prior detection of a refrigerant leak. This automatic interruption, whether or not there is a leak, ensures the safety of the refrigerant circuit. The safety system can be configured to receive a shutdown signal, for example, following an impact (e.g., from a vehicle's impact sensor), and upon receiving this shutdown signal, the safety system interrupts the refrigerant circulation.

[0083] In this case, the safety system is configured to interrupt the circulation of the refrigerant in the refrigerant circuit as described above.

[0084] The invention further relates to a method for protecting a thermal regulation system comprising a refrigerant circuit configured to use a refrigerant, in particular a flammable one, for example of the hydrocarbon type, in particular propane, the method comprising the following step: - interrupt the circulation of the refrigerant in the refrigerant circuit in case of risk of refrigerant leak, preferably by shutting off a compressor in the refrigerant circuit and / or by closing at least one valve in the refrigerant circuit.

[0085] The invention further relates to a thermal regulation system, in particular configured to be mounted on a vehicle, comprising: - a refrigerant circuit configured to use a flammable type of refrigerant, for example a hydrocarbon type refrigerant, in particular propane, - an enclosure in which the refrigerant circuit is placed and the enclosure contains an inert atmosphere for the flammable type refrigerant, the inert atmosphere containing for example nitrogen or argon for example.

[0086] The invention further relates to a thermal regulation system, in particular configured to be mounted on a vehicle, comprising: - a refrigerant circuit configured to use a flammable type of refrigerant, for example a hydrocarbon type refrigerant, in particular propane, - an enclosure in which the refrigerant circuit is placed and the enclosure includes a refrigerant capture device present in the enclosure, in particular the capture device being configured to adsorb or absorb the refrigerant.

[0087] The invention thus relates, independently or in combination with the foregoing, to a thermal regulation system, in particular configured to be mounted on a vehicle, comprising: - a refrigerant circuit configured to use a refrigerant, including a flammable type, for example a hydrocarbon-based refrigerant, such as propane, - a heat transfer fluid circuit that is configured to exchange heat with the refrigerant circuit, - a leak detector configured to detect the presence of refrigerant in the heat transfer fluid circuit or a refrigerant leak from the heat transfer fluid circuit.

[0088] There is a risk that the refrigerant from the refrigerant circuit may pass into the heat transfer fluid circuit and mix with the heat transfer fluid, particularly glycol water, and leaks may originate from this heat transfer fluid circuit. The invention makes it possible to detect the presence of refrigerant in the heat transfer fluid and any potential refrigerant leaks, thereby improving the overall safety of the thermal control system.

[0089] According to one aspect of the invention, the thermal regulation system comprises a housing in which the refrigerant circuit and at least part of the heat transfer fluid circuit are placed, and the refrigerant leak detector is in particular placed in the housing.

[0090] According to one aspect of the invention, the enclosure is provided with sealed walls and a vent configured to allow the gas present in the enclosure to exit to the outside of the enclosure through this vent, in particular when the pressure in the enclosure reaches the predetermined pressure threshold associated with the vent.

[0091] According to one aspect of the invention, the heat transfer fluid circuit includes an expansion vessel.

[0092] According to one aspect of the invention, the expansion vessel is in the enclosure.

[0093] According to one aspect of the invention, the refrigerant leak detector comprises a refrigerant sensor or a pressure sensor capable of detecting the presence of refrigerant in the expansion tank.

[0094] Alternatively, the refrigerant leak detector includes a refrigerant sensor or a pressure sensor capable of detecting the passage of refrigerant into a vent of the expansion vessel of the heat transfer fluid circuit, the refrigerant or pressure sensor being placed outside the expansion vessel.

[0095] According to one aspect of the invention, the refrigerant circuit comprises one or more two-fluid heat exchangers, and the refrigerant circuit and the circuit of heat transfer fluid being configured to mutually exchange heat, by the bi-fluid heat exchanger(s).

[0096] According to one aspect of the invention, the two-fluid heat exchangers are arranged in the enclosure.

[0097] According to one aspect of the invention, the thermal regulation system includes a safety system configured to interrupt the circulation of the heat transfer fluid in the heat transfer fluid circuit in the event of leak detection by the detector, in particular when the quantity of refrigerant leaking out of the heat transfer fluid circuit reaches a predetermined threshold or when the pressure measured out of the heat transfer fluid circuit reaches a predetermined interruption pressure threshold.

[0098] According to one aspect of the invention, the heat transfer fluid circuit is configured so that it can be segmented to obtain at least two heat transfer fluid circuit segments that are isolated from each other.

[0099] It may therefore be useful to provide for the possibility of segmenting not only the refrigerant circuit but also the heat transfer fluid circuit.

[0100] The invention further relates to a method for protecting a thermal regulation system comprising a refrigerant circuit using a refrigerant, in particular a flammable one, for example of the hydrocarbon type, in particular propane, and a heat transfer fluid circuit which is configured to exchange heat with the refrigerant circuit, the method comprising the following step: - detect the presence of refrigerant in the heat transfer fluid circuit (80) or a refrigerant leak from the heat transfer fluid circuit (80).

[0101] According to one aspect of the invention, the heat transfer fluid circuit is configured to be used to cool the passenger compartment, and / or battery modules, and / or the electric motor, and / or electronic modules.

[0102] It should be noted that the vent of the expansion vessel is separate from the vent of the enclosure.

[0103] According to one aspect of the invention, the enclosure contains an inert atmosphere for the hydrocarbon.

[0104] Other features, details and advantages of the invention will become clearer upon reading the following description on the one hand, and several exemplary embodiments given by way of illustration and not limitation with reference to the accompanying schematic drawings on the other hand, in which:

[0105] [Fig-1] Fig. 1 is a schematic representation of a regulation system thermal according to an example of an embodiment of the invention;

[0106] [Fig.2] Fig.2 is a schematic representation of a regulation system thermal according to another embodiment of the invention;

[0107] [Fig.3] Fig.3 is a schematic representation of a regulation system thermal according to yet another example of an embodiment of the invention;

[0108] The features, variants, and different embodiments of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive. In particular, variants of the invention may be conceived comprising only a selection of features, described hereafter in isolation from the other described features, if this selection of features is sufficient to confer a technical advantage and / or to differentiate the invention from the prior art.

[0109] Figure 1 shows a very schematic representation of a thermal control system 1 configured for installation on a vehicle, comprising a refrigerant circuit 50 configured to use a hydrocarbon-type refrigerant, in this case propane (also referred to as refrigerant R290). The refrigerant circuit 50 is configured to operate as a heat pump.

[0110] The refrigerant circuit 50 includes an electric compressor 51 configured to compress the refrigerant, and a condenser 52 (here a water condenser) arranged in series with the compressor 51. A degassing bottle 55 is arranged, in a conventional manner, in series with the condenser 52.

[0111] The thermal regulation system 1 also includes a heat transfer fluid circuit 80 (shown schematically in [Fig.1]), and several two-fluid heat exchangers 53 (also called "Chiller" in English) are provided, configured to exchange heat between the refrigerant circuit 50 and the heat transfer fluid circuit 80.

[0112] The heat transfer fluid circuit 80 includes a water pump 81, an expansion vessel 82 (or “surge tank” in English), and a multi-way valve 83.

[0113] The heat transfer fluid circuit 80, here a water circuit (using glycol water), can be used to cool the passenger compartment via an HVAC 60, and / or to cool battery modules 61, and / or to cool the electric motor 62, and / or to cool electronic modules 63, and / or to cool a cooling module 64.

[0114] The expansion vessel 82 allows the quantity of heat transfer fluid in the heat transfer fluid circuit 80 to be balanced by allowing heat transfer fluid to be supplied in case of deficit.

[0115] The refrigerant circuit 50 and part of the heat transfer fluid circuit 80 are placed in an enclosure 30. The two-fluid heat exchangers 53 and the expansion vessel 82 are placed in the enclosure 30.

[0116] The enclosure 30 is provided with sealed walls 31 and a vent 32 configured to allow the gas present in the enclosure 30 to exit the enclosure through this vent 32 when the pressure in the enclosure reaches the predetermined pressure threshold associated with the vent. The walls 32 of the enclosure may, for example, be fireproof and / or mechanically reinforced, for example using a composite material.

[0117] The vent 32 is here a valve configured to be able to open when the pressure inside the enclosure 30 reaches the predetermined pressure threshold associated with the vent in order to lower the pressure in the enclosure 30.

[0118] Alternatively, the vent is a membrane configured to allow gas (which may then contain gaseous hydrocarbons) to pass through when the pressure reaches the predetermined pressure threshold associated with the vent. The vent 32 is notably made of porous bronze.

[0119] In any event, the vent 32 is configured to prevent a flame formed outside the enclosure 30 from entering the enclosure through the vent 32. In particular, the vent 32 is configured to prevent the flame from rising back into the enclosure, thus blocking flame propagation within the enclosure. This is particularly advantageous from a safety standpoint, preventing a fire from spreading inside the enclosure 30. In the case of propane, the vent 32 is characterized by a hydraulic diameter-to-wall thickness ratio (equivalent to the vent length) of less than 3.6%.

[0120] The thermal regulation system 1 includes a hydrocarbon adsorption or absorption device 40 configured to adsorb or absorb hydrocarbon present in the enclosure.

[0121] The device 40, for example with activated carbon, comprises several blocks arranged in different locations within the enclosure 30.

[0122] The enclosure 30 can contain an inert atmosphere for the hydrocarbon. The inert atmosphere contains nitrogen or argon, for example. This prevents the propane from reacting chemically with the atmosphere in the enclosure 30, thus avoiding, for example, combustion.

[0123] The thermal control system 1 includes a refrigerant leak detector 45 configured to detect a refrigerant leak from the refrigerant circuit 50. The detector 45 is part of a safety system 49 configured to interrupt the circulation of the refrigerant in the refrigerant circuit 50 in the event of a leak being detected by the leak detector 45.

[0124] The leak detector 45 is placed in the enclosure 30, and includes a gas sensor 46, here a propane sensor.

[0125] The thermal control system 1 is configured to deliver leakage information, for example in the form of an audible or visual alarm, when the sensor gas detector 46 detects a gas concentration in the interior space of enclosure 30 which reaches the predetermined concentration threshold.

[0126] In another example of an implementation of the invention, the leak detector 45 may include a pressure sensor configured to measure the pressure in the enclosure 30.

[0127] This pressure sensor detects a possible refrigerant leak from the refrigerant circuit if the measured pressure reaches the predetermined interruption pressure threshold. The pressure increase corresponds to an accumulation of gas (here, propane) in enclosure 30.

[0128] In yet another embodiment of the invention, the pressure sensor can be configured to measure the pressure in the refrigerant circuit 50. The pressure sensor is, in particular, placed within the refrigerant circuit 50. This pressure sensor makes it possible to detect a possible refrigerant leak from the refrigerant circuit if the measured pressure drops below a predetermined internal pressure threshold. The pressure drop corresponds to a leak of refrigerant (here, propane) outside the refrigerant circuit. The predetermined internal pressure threshold is defined according to the sensor's location in the circuit (for example, upstream or downstream of the compressor).

[0129] The thermal control system 1 is configured to interrupt the circulation of the refrigerant in the refrigerant circuit 50 in the event of detection of a leak, when the concentration of refrigerant outside the refrigerant circuit 50 reaches a predetermined threshold or when the pressure measured outside the refrigerant circuit reaches the predetermined interruption pressure threshold.

[0130] The leak detection thresholds indicated above are chosen based on the lower explosive limit (LEL). The lower explosive limit (LEL) of a combustible gas or vapor designates the minimum concentration above which the substance can be ignited. The lower explosive limit (LEL) is expressed as a percentage (%) by volume in air. Below the lower explosive limit (LEL), the mixture is too lean in fuel to initiate any reaction. In one embodiment of the invention, the leak detection threshold, or concentration threshold, is less than 50% of the lower explosive limit (LEL) of propane, which is approximately 2.2% or 2.3%.For example, when the propane concentration reaches 1.1% (i.e., 50% of 2.2%), a leak is considered to have occurred, and the safety system 49 implements the interruption of refrigerant circulation in the refrigerant circuit. An alarm trigger threshold (e.g., a visual or audible alarm) can be set below the leak detection threshold, or concentration threshold, for example, with a margin of 20%. In the given example, with a margin of 20%, . The alarm trigger threshold can be 0.88% propane concentration (0.88% = l, l% * (l - 20%)). Therefore, an audible alarm can be triggered as soon as the propane concentration reaches 0.88%.

[0131] The safety system 49 is configured to interrupt the circulation of refrigerant in the refrigerant circuit by shutting down a compressor 51 of the refrigerant circuit 50. This makes it possible to limit / slow down the refrigerant leak. Conversely, if the compressor 51 continues to operate while a leak occurs, then the leak continues, or even intensifies, because the compressor 51 continues to maintain refrigerant circulation.

[0132] The refrigerant sensor 46 is preferably placed in the enclosure 30, near a vent 89 (degassing vent) of the expansion vessel 82 of the heat transfer fluid circuit 80, and configured to detect the passage of refrigerant through the vent 89 of the expansion vessel 82.

[0133] The refrigerant sensor 46 is located outside the expansion vessel 82.

[0134] It is of course possible to provide several refrigerant sensors 46 placed at different locations inside the enclosure 30.

[0135] In the described implementation example, the refrigerant circuit 50 is configured so that it can be segmented to obtain at least two refrigerant circuit segments that are isolated from each other when a refrigerant leak is detected.

[0136] Thus, in the event of a leak, propane cannot pass from one segment to another, so that if the leak involves one of the segments, the amount of refrigerant that leaks is limited to the amount of refrigerant present in that segment. The refrigerant contained in the other segment(s) remains trapped and cannot leak. This reduces the amount of refrigerant that leaks out of the refrigerant circuit.

[0137] For this purpose, the refrigerant circuit 50 includes several valves 70 configured to segment the refrigerant circuit 50 into different segments, for example into 2, 3, 4, 5 or 6 segments.

[0138] By closing one of the valves 70, it is possible to isolate two segments of the circuit on either side of this valve.

[0139] We will continue to describe in more detail, with reference to figures 2 and 3, these valves 70 and their placement in the refrigerant circuit 50.

[0140] In the example of [Fig.2], a valve 71, in particular of the type shut-off valve or in English “Shut Off Valve” (SOV), is placed between the compressor 51 and the condenser 52.

[0141] The refrigerant circuit 50 includes an internal heat exchanger 77 (often referred to by the acronym IHX) configured to transfer heat between a low-pressure and a high-pressure part of the refrigerant circuit 50.

[0142] In this example, the refrigerant circuit 50 includes two other valves 72 of the closed expansion open valve type (or in English “Closed expansion open valve” or CEO).

[0143] Other types of valves may be used, for example an open expansion valve (or in English "Open expansion valve" or CO).

[0144] The valves 72 are each placed in series with one of the two-fluid heat exchangers 53, between the internal heat exchanger 77 and the two two-fluid heat exchangers 53 (which are mounted in parallel).

[0145] Thus, in the event of a leak, the valves 71 and 72 are closed by the safety system 49 so as to define two segments 90 and 91. Segment 90 corresponds to the parts of the refrigerant circuit 50 between the valve 71 and the valves 72, and segment 91 corresponds to the parts of the refrigerant circuit 50 between the valves 72 and the valve 71.

[0146] The safety system 49 includes, for example, control electronics which, upon receiving a safety shutdown command, control the closing of the valves. The safety shutdown command is issued when a leak is detected.

[0147] In the example of [Fig.3], a second valve 73, of the type of shut-off valve or in English "Shut Off Valve" (SOV), is placed between the degassing bottle 55 and the condenser 52. The degassing bottle 55 is configured to remove moisture from the refrigerant and can also serve as a buffer tank for the refrigerant.

[0148] The compressor 51 can be configured to segment the refrigerant circuit 50 upstream and downstream of the compressor 51. In this case, for the example of [Fig.2], the refrigerant circuit 50 can include an additional segment 93 between the compressor 51 and the valve 71. In this case, the refrigerant circuit 50 can be segmented into three segments 90, 91 and 93.

[0149] It is thus possible to form three segments by closing the four valves 71, 72 and 73. These three segments are: - a first segment 94 between valve 71 and valve 73, - a second segment 95 between valve 71 and valves 72, - a third segment 96 between valves 72 and valve 73.

[0150] The invention makes it possible to isolate these three segments 94, 95 and 96, so that in the event of a leak, only one of the segments leaks.

[0151] It is advantageous to position the valves 71 (SOV valves) or 72 (CEO valves) in the locations which have the most load, namely around the condenser 52 or, where appropriate, around the condenser 52 and a heat accumulator in the case of an economizer.

[0152] The valves are either placed in a housing (also called a "manifold" in English) or welded to prevent further leaks related to their assembly.

[0153] The volume of enclosure 30 is for example between 20 and 25 liters.

[0154] In an example of an embodiment of the invention not shown, the heat transfer fluid circuit is configured so that it can be segmented to obtain at least two heat transfer fluid circuit segments that are isolated from each other.

[0155] Indeed, the refrigerant can mix with the heat transfer fluid, in particular glycol water, and leaks can come from this heat transfer fluid circuit, in addition to the refrigerant circuit.

[0156] It may therefore be useful to provide for the possibility of segmenting not only the refrigerant circuit but also the heat transfer fluid circuit.

Claims

Demands

1. Thermal control system (1), in particular configured to be mounted on a vehicle, comprising: - a refrigerant circuit (50) configured to use a refrigerant, in particular of a flammable type, for example a hydrocarbon type refrigerant, in particular propane, - an enclosure (30) in which the refrigerant circuit (50) is placed, the enclosure being provided with sealed walls (31) and a vent (32) configured to allow the gas present in the enclosure to exit to the outside of the enclosure through this vent (32), in particular when the pressure in the enclosure reaches a predetermined pressure threshold associated with the vent.in which the enclosure (30) also receives, in addition to the refrigerant circuit (50), at least part of a heat transfer fluid circuit (80), the heat transfer fluid circuit comprising an expansion vessel (82), a refrigerant leak detector (46) being placed in the enclosure to detect the passage of refrigerant through a vent in the expansion vessel.

2. Thermal regulation system according to the preceding claim, wherein the vent (32) is configured to, in particular as a function of the pressure inside the enclosure (30), lower the pressure in the enclosure, in particular the vent being a valve configured to be able to open when the pressure reaches or exceeds the predetermined pressure threshold associated with the vent or the vent being a membrane configured to allow gas to pass through when the pressure reaches or exceeds the predetermined pressure threshold associated with the vent.

3. Thermal regulation system according to any one of the preceding claims, wherein the vent (32) is configured to prevent a flame formed outside the enclosure from entering the enclosure, through the vent (32).

4. A thermal control system according to any one of the preceding claims, comprising a safety system (49) including a refrigerant leak detector (45) configured to detect a refrigerant leak from the refrigerant circuit (50), and the system safety (49) is configured to interrupt the circulation of the refrigerant in the refrigerant circuit (50) in the event of leak detection by the detector, in particular when the concentration of refrigerant outside the refrigerant circuit (50) reaches or exceeds a predetermined concentration threshold or when the pressure measured outside the refrigerant circuit (50) reaches or exceeds a predetermined interruption pressure threshold.

5. Thermal control system according to the preceding claim, wherein the safety system (49) is configured to interrupt the circulation of the refrigerant in the refrigerant circuit (50) by stopping a compressor (51) of the refrigerant circuit (50).

6. Thermal control system according to any one of the preceding claims, wherein the refrigerant circuit (50) is configured to be segmented so as to obtain at least two segments of refrigerant circuit (50) which are isolated from each other when a refrigerant leak is detected.

7. Thermal control system according to the preceding claim, wherein the refrigerant circuit (50) includes one or more valves configured to segment the refrigerant circuit (50) into different segments (90, 91), including at least one expansion valve or an open closed expansion valve or an open expansion valve.

8. Thermal control system according to any one of the preceding claims, wherein the thermal control system comprises a hydrocarbon adsorption or absorption device (40) configured to adsorb or absorb hydrocarbon present in the enclosure (30).

9. Thermal regulation system according to any one of the preceding claims, wherein the enclosure (30) contains an inert atmosphere for the refrigerant.

10. A method for protecting a thermal control system comprising a refrigerant circuit (50) using a refrigerant, in particular a flammable one, for example of the hydrocarbon type, in particular propane, the method comprising the following step: - placing the refrigerant circuit (50) in an enclosure (30) provided with sealed walls (31) and a vent (32) configured to allow the gas present in the enclosure to exit to the outside of the enclosure through this vent (32), particularly when the pressure in the enclosure reaches a predetermined pressure threshold associated with the vent.

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