Air conditioning equipment for recreational vehicles

Abstract

An air conditioning device (1) for a recreational vehicle comprises a refrigeration circuit for circulating a refrigerant fluid, the refrigeration circuit comprising: a condenser (2); an expansion valve (3); an evaporator (4) for exchanging heat with the interior of the recreational vehicle to be air-conditioned; a compressor (5); and a leak detection system comprising: a refrigerant fluid sensor (72) configured to detect a control parameter (720) representing a physical condition of the refrigerant fluid at the outlet of the evaporator (4) or at the inlet of the condenser (2); and a control unit (8) connected to the refrigerant fluid sensor (72) and the compressor (5).

Description

Technical Field

[0001] The invention relates to an air conditioning device for a recreational vehicle; moreover, the invention relates to a recreational vehicle and a method for supplying conditioned air in a recreational vehicle. Background Art

[0002] Air conditioning equipment for recreational vehicles typically includes a refrigeration circuit for a refrigerant fluid, a condenser, an expansion device, an evaporator, a compressor, and an electric motor for driving the compressor.

[0003] In particular, the field of this patent application is the detection of leaks of refrigerant fluids in refrigeration systems. In fact, the diffusion of natural refrigerant fluids is potentially explosive and / or toxic, and it is crucial to detect leaks of refrigerant fluids in a timely manner before a fire or explosion occurs.

[0004] Refrigerant fluid leak detection systems are known, for example, from the following patent documents: EP 3255360 B1, WO 2006025880 A1, WO 2013119489 A2, US 5214918 A, GB 2553972 A, WO 2013 / 119489 A2, and US 7558700 B2. These known systems have limitations in terms of reliability and speed of leak detection. Furthermore, these systems are complex in architecture. Summary of the Invention

[0005] The scope of the present invention is to provide an air conditioning unit for a recreational vehicle and a method for detecting a refrigerant fluid leak in a refrigeration circuit of a recreational vehicle, which method improves upon the above-mentioned prior art.

[0006] This scope is achieved by an air conditioning device and a method according to one or more of the appended claims.

[0007] The present disclosure relates to an air conditioning system for a recreational vehicle. The air conditioning system (hereinafter referred to as the system) includes a refrigerant fluid. Preferably, the refrigerant fluid is a natural refrigerant fluid, such as carbon dioxide (CO2, R-744), propane (R-290), isobutane (R-600a), propylene (R-1270), and ammonia (NH3, R-717).

[0008] The apparatus includes a refrigeration circuit. The refrigeration circuit is configured to circulate a refrigerant fluid. The refrigeration circuit includes a first heat exchanger. The first heat exchanger exchanges heat with the external environment (i.e., provides heat exchange between the external environment and the refrigerant fluid). In cooling mode, the first heat exchanger is configured to condense the refrigerant fluid and thus defines a condenser (hereinafter, the first heat exchanger is also referred to as the condenser). The refrigeration circuit includes an expansion valve configured to expand the refrigerant fluid. The refrigeration circuit includes a second heat exchanger. The second heat exchanger exchanges heat with the interior of a recreational vehicle to be air-conditioned (i.e., provides heat exchange between the interior of the recreational vehicle and the refrigerant fluid). In cooling mode, the second heat exchanger is configured to evaporate the refrigerant fluid and thus defines an evaporator (hereinafter, the second heat exchanger is also referred to as the evaporator). The refrigeration circuit includes a compressor configured to compress the refrigerant fluid.

[0009] In cooling mode, the refrigerant fluid circulates from the compressor to the condenser, from the condenser to the expansion valve, from the expansion valve to the evaporator, and from the evaporator back to the condenser. Specifically, the evaporator has an inlet connected to the expansion valve and an outlet connected to the compressor. The condenser has an inlet connected to the compressor and an outlet connected to the expansion valve.

[0010] The apparatus further includes a leak detection system. The leak detection system includes a refrigerant fluid sensor configured to detect a control parameter representing a physical condition of the refrigerant fluid at the outlet of the evaporator or at the inlet of the condenser. The leak detection system includes a control unit connected to the refrigerant fluid sensor and configured to receive (preferably, receive in real time) the control parameter from the refrigerant fluid sensor. The control unit may include a PCB (printed circuit board).

[0011] The refrigerant fluid sensor may be, for example, a pressure sensor; in this case, the control parameter represents the refrigerant fluid pressure at the outlet of the evaporator or at the inlet of the condenser. Furthermore, the refrigerant fluid sensor may be a temperature sensor; in this case, the control parameter represents the refrigerant fluid temperature at the outlet of the evaporator or at the inlet of the condenser.

[0012] According to one aspect of the present disclosure, the control unit is further connected to the compressor and is configured to receive (preferably, receive in real time) a compressor operating signal from the compressor, the compressor operating signal indicating the operating state of the compressor. The control unit is configured to select a reference value previously memorized in a database (which may be included in the device or may be remote) based on the compressor operating signal. The control unit is configured to compare the value(s) of the control parameter with the reference value to generate a diagnostic parameter for evaluating a leakage condition. The reference value provides a value mapping with which the control parameter detected by the refrigerant fluid sensor is compared. For example, the reference value may include a maximum value and a minimum value of the control parameter; if the control parameter is not included between the minimum value and the maximum value, a leakage condition is evaluated. In another example, the reference value may include an optimal value and a tolerance value of the control parameter; if the control parameter is not included between the optimal value minus the tolerance value and the optimal value plus the tolerance value, a leakage condition is evaluated.

[0013] Preferably, the leak detection system further includes an indoor temperature sensor. The indoor temperature sensor is configured to detect an indoor temperature signal representing the indoor temperature of the room to be air-conditioned. The indoor temperature sensor is connected to the control unit. The control unit is configured to receive the indoor temperature signal from the indoor temperature sensor in real time. Preferably, the control unit is configured to select a reference value based on the indoor temperature signal (alternatively or additionally, based on the compressor operating signal).

[0014] In an embodiment, the leak detection system further includes an ambient temperature sensor. The ambient temperature sensor is configured to detect an ambient temperature signal representing the ambient temperature in the outside environment (or outside the recreational vehicle). The ambient temperature sensor is connected to a control unit. The control unit can be configured to receive the ambient temperature signal from the ambient temperature sensor in real time. Preferably, the control unit is configured to select a reference value based on the ambient temperature sensor (alternatively or additionally, based on the compressor operating signal and / or the indoor temperature signal).

[0015] Preferably, the control unit is connected (or connectable) to a memory. The memory may or may not be included in the device. The control unit is configured to store control parameters and / or compressor operating signals received at the control unit at each of a plurality of successive moments in time in the memory. In particular, the plurality of successive moments include at least a previous moment, which is before the actual moment. The plurality of successive moments may also include the actual moment. The control unit may be configured to compare the control parameters received in real time at the actual moment with the control parameters stored in the memory at the previous moment, and to generate an alarm signal based on the deviation of the control parameters received in real time at the actual moment from the control parameters stored in the memory at the previous moment; in particular, the control unit may be configured to generate an alarm signal if the deviation exceeds a reference threshold. The reference threshold is stored in the memory. Thus, the control unit may be configured to monitor the trend of the control parameters; this allows leaks to be identified promptly and immediately when they occur.

[0016] The device may include a monitor configured to display a diagnostic parameter (particularly the value of the diagnostic parameter received in real time and / or the value of the diagnostic parameter at multiple moments in time, thereby providing a trend of the diagnostic parameter over time). Thus, a user can monitor the diagnostic parameter and, if a leak is assessed, shut down the device and / or initiate a safety procedure. Furthermore, in at least one embodiment, the control unit can automatically shut down the device (e.g., by shutting down the compressor) based on the diagnostic parameter.

[0017] The function of the alarm signal is to warn the user if a control parameter is changing in an abnormal manner (e.g., if the pressure drops too quickly). Thus, the alarm signal can be a clue that a leak exists (although it can also indicate other defects). The alarm signal can be displayed on the monitor and / or can include an audible signal. It is noted that the alarm signal can define a diagnostic parameter (which corresponds to the diagnostic parameter) or can be a different signal.

[0018] In an embodiment, the alarm signal may command the device to stop, requiring action by the user to restart (eg, after having verified by reading diagnostic parameters whether a leak actually exists).

[0019] The previous moment can be a (single) initial moment, wherein at each actual moment, the parameter received in real time at the control unit is compared with the parameter stored in the memory at the (single) initial moment (which remains unchanged). Alternatively, at each of a plurality of successive moments, the control unit can store an updated value of the parameter in the memory and compare the parameter received in real time with the parameter stored in the memory at the moment immediately before (or immediately preceding) the actual moment. In this case, the trend of the parameter over time is stored in the memory.

[0020] In at least one embodiment, the control unit is configured to select the reference threshold value from among a plurality of values ​​stored in the database according to the indoor temperature signal and / or the outside temperature signal.

[0021] In at least one embodiment, the control unit is configured to select a reference threshold value based on a difference between a compressor operating signal received in real time at an actual moment and a compressor operating signal stored in a memory at a previous moment. It is observed that the reference threshold value can be selected based on the indoor temperature signal, and / or the outdoor temperature signal, and / or the compressor operating signal, and / or the difference between the compressor operating signal at an actual moment and the compressor operating signal at a previous moment.

[0022] According to one aspect of the present disclosure, a refrigerant fluid sensor is connected to the refrigeration circuit at the outlet of the evaporator. The leak detection system may include an additional refrigerant fluid sensor connected to the refrigeration circuit at the inlet of the condenser. The additional refrigerant fluid sensor is configured to detect an additional control parameter that is indicative of a physical condition of the refrigerant fluid at the inlet of the condenser.

[0023] The additional refrigerant fluid sensor may be, for example, a pressure sensor; in which case the control parameter represents the refrigerant fluid pressure at the inlet of the condenser. Furthermore, the additional refrigerant fluid sensor may be a temperature sensor; in which case the control parameter represents the refrigerant fluid temperature at the inlet of the condenser.

[0024] The control unit may be further connected to an additional refrigerant fluid sensor. The control unit may be further configured to receive additional control parameters in real time. It is observed that in an embodiment, an additional refrigerant fluid sensor is provided (at the inlet of the condenser), but no refrigerant fluid sensor is provided (at the outlet of the evaporator).

[0025] In at least one embodiment, the control unit is configured to store additional control parameters for each of a plurality of consecutive moments in a memory. The control unit can be configured to generate an alarm signal based on a (further) deviation of the additional control parameters at the actual moment received in real time relative to the additional control parameters at the previous moment stored in the memory. In particular, the control unit can be configured to generate the alarm signal if the (additional) deviation exceeds an (additional) reference threshold. In at least one embodiment, the control unit is configured to select the (additional) reference threshold from a plurality of values ​​stored in a database based on the indoor temperature signal, and / or the outdoor temperature signal, and / or the compressor operating signal, and / or the difference between the compressor operating signal at the actual moment and the compressor operating signal at the previous moment.

[0026] In at least one embodiment, the control unit is configured to select additional reference values ​​previously memorized in the database based on the compressor operating signal, and / or the indoor temperature signal, and / or the external temperature signal, and compare the value of the control parameter with the reference value to generate a diagnostic parameter for evaluating the leakage condition.

[0027] In at least one embodiment, the control unit is configured to calculate a differential control parameter as a difference between the control parameter and the additional control parameter.

[0028] The control unit can be configured to select a differential reference value previously stored in a database based on the compressor operating signal, and / or the indoor temperature signal, and / or the outdoor temperature signal, and compare the differential control parameter with the reference value to generate the diagnostic parameter. For example, the differential reference value may include a minimum and maximum value of the differential control parameter, or an optimal value and a tolerance value of the differential control parameter. The differential reference value may define the reference value, or be further provided to the reference value. It is observed that the differential reference value depends on the compressor state (on / off) and is therefore preferably selected based on the compressor operating signal. In fact, when the compressor is turned off, the pressure of the refrigerant fluid at the inlet of the condenser and the pressure at the outlet of the evaporator are the same, and in the absence of leakage, the value of this pressure varies with the temperature of the room and / or the outdoor environment. When the compressor is turned on, the pressure of the refrigerant fluid at the inlet of the condenser is higher than the pressure at the outlet of the evaporator, and the difference between these pressures depends on the temperature of the room and / or the outdoor environment.

[0029] The control unit may be configured to store the differential control parameter at each of a plurality of consecutive moments in a memory. The control unit may be configured to generate an alarm signal based on a deviation of the differential control parameter at the actual moment, calculated in real time, relative to the differential control parameter at the previous moment, stored in the memory. In particular, the control unit may be configured to generate an alarm signal if the deviation between the differential control parameter at the actual moment, calculated in real time, and the differential control parameter at the previous moment, stored in the memory, exceeds a differential reference threshold. In at least one embodiment, the control unit is configured to select the differential reference threshold from a plurality of values ​​stored in a database based on an indoor temperature signal, and / or a compressor operating signal, and / or a difference between the compressor operating signal at the actual moment and the compressor operating signal at the previous moment, and / or an ambient temperature signal.

[0030] According to one aspect of the present disclosure, a control unit is configured to calculate a leakage parameter based on one or more of the following: a control parameter, an additional control parameter, a differential control parameter, an indoor temperature measured in the room to be conditioned, and an ambient temperature. The control unit is configured to compare the leakage parameter with previously recorded minimum and / or maximum thresholds to generate a diagnostic parameter. Preferably, the minimum and / or maximum thresholds for the leakage parameter are fixed, i.e., the minimum and / or maximum thresholds do not vary with the indoor temperature or the power consumed by the compressor.

[0031] For example, the leakage parameter may be calculated as the difference between the pressure at the inlet of the condenser and the pressure at the outlet of the evaporator, said difference being divided by the pressure at the inlet of the condenser (or divided by the pressure at the outlet of the evaporator).

[0032] In at least one embodiment, the control unit is configured to select a minimum and / or maximum threshold value from a plurality of values ​​stored in a database based on an indoor temperature signal, and / or a compressor operating signal, and / or a difference between the compressor operating signal at an actual moment and the compressor operating signal at a previous moment, and / or an external temperature signal.

[0033] According to an embodiment of the present disclosure, the leak detection system includes a power sensor (or current sensor) connected to the compressor and configured to measure the power (or current) absorbed by the compressor; in this case, the compressor operating signal may represent the power (or current) absorbed by the compressor. According to another embodiment, the compressor operating signal may be a binary parameter representing the state of the compressor (on or off).

[0034] In at least one embodiment, the apparatus includes a four-way valve connected to the refrigeration circuit and operable in a first position to operate the apparatus in a cooling mode and in a second position to operate the apparatus in a heating mode.

[0035] In heating mode, the first heat exchanger is configured to evaporate the refrigerant fluid and thus operates as an evaporator.In heating mode, the second heat exchanger is configured to condense the refrigerant fluid and thus operates as a condenser.

[0036] In heating mode, the refrigerant fluid circulates from the compressor to the condenser (which is the second heat exchanger in this mode), from the condenser to the expansion valve, from the expansion valve to the evaporator (which is the first heat exchanger in this mode), and from the evaporator back to the condenser.

[0037] The control unit can be configured to select a reference value (and / or additional reference value, and / or differential reference value, and / or minimum and / or maximum threshold value of the leakage parameter) from among multiple values ​​memorized in the database, also depending on whether the four-way valve is in the first position or the second position.

[0038] The present disclosure also provides a method for detecting a refrigerant fluid leak in a refrigeration circuit of a recreational vehicle (recreational vehicle refrigeration circuit).

[0039] The method comprises the step of detecting a control parameter representative of the physical condition (pressure or temperature) of the refrigerant fluid at the outlet of the evaporator or at the inlet of the condenser.

[0040] The method includes the steps of receiving, at a control unit in real time, a control parameter and a compressor operating signal representing an operating state of the compressor.

[0041] According to one aspect of the present disclosure, the method includes the step of selecting a reference value previously memorized in a database according to a compressor operating signal; the method also includes the step of comparing the value of the control parameter with the reference value and generating a diagnostic parameter for evaluating a leakage condition.

[0042] The method may further include the step of detecting an indoor temperature signal via an indoor temperature sensor, the indoor temperature signal representing the indoor temperature of the room to be air-conditioned. The method may then include the step of receiving (preferably, in real time) the indoor temperature signal at the control unit. In this case, the reference value may also be selected based on the indoor temperature signal.

[0043] The method may further include the step of detecting an ambient temperature signal by an ambient temperature sensor, the ambient temperature signal being indicative of the ambient temperature of the external environment. The method may then include the step of receiving (preferably, in real time) the ambient temperature signal at the control unit. In this case, the reference value may also be selected based on the ambient temperature signal.

[0044] In at least one embodiment, the method includes the step of storing the control parameters and the compressor operating signal at each of a plurality of consecutive moments received at the control unit in a memory. In particular, the plurality of consecutive moments include at least a previous moment, which is before the actual moment. The method may further include the steps of comparing the control parameters at the actual moment received in real time with the control parameters at the previous moment stored in the memory, and generating an alarm signal based on the deviation of the control parameters at the actual moment received in real time relative to the control parameters at the previous moment stored in the memory. In particular, if the deviation exceeds a reference threshold, an alarm signal is generated. In at least one embodiment, the method may further include the steps of selecting a reference threshold based on the difference between the compressor operating signal at the actual moment received in real time and the compressor operating signal at the previous moment stored in the memory, and / or based on the indoor temperature signal and / or the external ambient temperature signal.

[0045] In at least one embodiment, the control parameter is representative of the physical condition of the refrigerant fluid at the outlet of the evaporator, and the method includes the step of detecting an additional control parameter representative of the physical condition of the refrigerant fluid at the inlet of the condenser.

[0046] The method may further comprise the step of calculating a differential control parameter as a difference between the control parameter and the additional control parameter.

[0047] In at least one embodiment, the method includes the steps of selecting a differential reference value previously memorized in a database based on a compressor operating signal, and / or an indoor temperature signal, and / or an external ambient temperature signal, and comparing the differential control parameter with the reference value to generate a diagnostic parameter.

[0048] According to one aspect of the present disclosure, the method includes the step of calculating a leakage parameter based on one or more of the following: a control parameter, an additional control parameter, a differential control parameter, an indoor temperature measured in the room to be conditioned, and an ambient temperature measured in the ambient environment. Thus, the method may include the step of comparing the leakage parameter with previously memorized minimum and / or maximum thresholds to generate a diagnostic parameter. The method may also include the step of selecting a minimum and / or maximum threshold from a plurality of values ​​stored in a database based on an indoor temperature signal, a compressor operating signal, a difference between the compressor operating signal at a current moment and the compressor operating signal at a previous moment, and / or an ambient temperature signal.

[0049] The method may also include a calibration step, comprising deriving reference values ​​and memorizing these reference values ​​in a database. The reference values ​​are derived by operating the device under various conditions with a specific room temperature, a specific power drawn by the compressor, and / or a specific ambient temperature, and detecting the values ​​of the control parameters and / or additional control parameters under these conditions. The detected values ​​(ultimately corrected for a certain tolerance) provide the reference values. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] These and other features of the present invention will become more apparent from the following detailed description of preferred non-limiting exemplary embodiments of the present invention, with reference to the accompanying drawings, in which:

[0051] - Figure 1 An air conditioning apparatus according to the present disclosure is presented;

[0052] - Figure 2 A possible embodiment of the air conditioning device according to claim 1 is presented, wherein the device is capable of operating in cooling mode as well as in heating mode;

[0053] - Figure 3 The possible variations of the control parameters as a function of the indoor temperature of the room to be conditioned and the power absorbed by the compressor are shown (in particular, Figure 3 Each curve shown represents a possible value of a control parameter for a certain power absorbed by the compressor as a function of the indoor temperature). DETAILED DESCRIPTION

[0054] Referring to the drawings, reference numeral 1 denotes an air conditioning apparatus for a recreational vehicle (hereinafter referred to as the apparatus).

[0055] The air conditioning device includes a refrigeration circuit for circulating a refrigerant fluid. The refrigeration circuit includes a condenser 2, an expansion valve 3, an evaporator 4, and a compressor 5. It is observed here that the terms "condenser" and "evaporator" refer to the operation of the refrigeration circuit in cooling mode.

[0056] The air conditioning equipment includes a leak detection system. The leak detection system includes one or more of the following:

[0057] a refrigerant fluid sensor 72 connected to the refrigeration circuit at the outlet of the evaporator 4 (i.e., in the branch of the circuit comprised between the evaporator 4 and the compressor 5) and configured to detect the temperature or pressure of the refrigerant fluid;

[0058] an additional refrigerant fluid sensor 74 connected to the refrigeration circuit at the inlet of the condenser 2 (i.e. in the branch of the circuit included between the condenser 2 and the compressor 5) and configured to detect the temperature or pressure of the refrigerant fluid;

[0059] A power sensor (or current sensor) 73 connected to the compressor 5 and configured to measure the power (or current) absorbed by the compressor 5 .

[0060] The leak detection system comprises a control unit 8 which is connected to a refrigerant fluid sensor 72 , and / or an additional refrigerant fluid sensor 74 , and / or a power sensor 73 .

[0061] In particular, the refrigerant fluid sensor 72 , if provided, is configured to send to the control unit 8 a control parameter 720 representative of the temperature or pressure of the refrigerant fluid in the branch comprised by the circuit between the evaporator 4 and the compressor 5 .

[0062] The additional refrigerant fluid sensor 74 , if provided, is configured to send to the control unit 8 an additional control parameter 740 representative of the temperature or pressure of the refrigerant fluid in the branch comprised by the circuit between the condenser 2 and the compressor 5 .

[0063] Preferably, both the refrigerant fluid sensor 72 and the additional refrigerant fluid sensor 74 are pressure sensors, which are configured to detect the pressure value of the refrigerant fluid in the branch of the circuit between the evaporator 4 and the compressor 5 or in the branch of the circuit between the condenser 2 and the compressor 5, respectively.

[0064] The power sensor 73 (if provided) is configured to send a compressor operator signal 730 to the control unit 8, which is indicative of the operating status of the compressor (in the embodiment, in particular of the actual power absorbed by the compressor 5).

[0065] The leak detection system further includes an indoor temperature sensor 71 configured to detect an indoor temperature T0 in the interior of the leisure vehicle to be air-conditioned. The indoor temperature sensor 71 is connected to the control unit 8 and configured to send an indoor temperature signal 710 to the control unit 8, the indoor temperature signal indicating the indoor temperature T0.

[0066] In an embodiment, the control unit 8 is connected to a database (which may or may not be included in the device) comprising a plurality of reference values. The control unit 8 is configured to select one or more reference values ​​from among the plurality of reference values ​​according to one or more of the following:

[0067] - Compressor operator signal 730;

[0068] - Indoor temperature signal 710.

[0069] In an embodiment, the control unit 8 is configured to compare the value of the control parameter 720 and / or the additional control parameter 740 with a reference value to generate a diagnostic parameter for assessing a leakage condition.

[0070] In an embodiment, the control unit 8 is configured to calculate a differential control parameter as the difference between the control parameter 720 and the additional control parameter 740 .

[0071] In an embodiment, the control unit 8 is configured to calculate the leakage parameter according to one or more of the following: the control parameter 720 , the additional control parameter 740 , the indoor temperature T 0 , and the differential parameter.

[0072] In an embodiment, the control unit 8 is connected to a memory 81 (which may or may not be included in the device 1) and is configured to store in the memory 8 at least an initial moment (or preferably each of a plurality of successive moments equidistant from one another) one or more of the following:

[0073] - control parameters 720;

[0074] - Additional control parameters 740;

[0075] - Indoor temperature T0;

[0076] - Differential control parameters;

[0077] - Leakage parameters.

[0078] In an embodiment, the control unit 8 is configured to compare the control parameter 720 received in real time with the control parameter at the initial moment or the previous moment in multiple moments stored in the memory 81, and if the deviation between the control parameter 720 received in real time and the control parameter stored in the memory 81 exceeds a certain threshold (the threshold can be selected by the memory based on the indoor temperature T0, and / or based on the difference between the indoor temperature T0 at the actual moment and the indoor temperature at the initial moment or the previous moment, and / or based on the compressor operator signal 730, and / or based on the difference between the compressor operator signal 730 at the actual moment and the compressor operator signal 730 at the initial moment or the previous moment), an alarm signal is generated.

[0079] In an embodiment, the control unit 8 is configured to compare the additional control parameters 740 received in real time with the control parameters at the initial moment or the previous moment in multiple moments stored in the memory 81, and if the deviation between the additional control parameters 740 received in real time and the additional control parameters stored in the memory 81 exceeds a certain threshold (the threshold can be selected by the memory based on the indoor temperature T0, and / or based on the difference between the indoor temperature T0 at the actual moment and the indoor temperature at the initial moment or the previous moment, and / or based on the compressor operator signal 730, and / or based on the difference between the compressor operator signal 730 at the actual moment and the compressor operator signal 730 at the initial moment or the previous moment), an alarm signal is generated.

[0080] In an embodiment, the control unit 8 is configured to compare the differential control parameter calculated in real time with the differential control parameter at the initial moment or a previous moment in multiple moments stored in the memory 81, and if the deviation between the differential control parameter calculated in real time and the differential control parameter stored in the memory 81 exceeds a certain threshold (the threshold can be selected by the memory based on the indoor temperature T0, and / or based on the difference between the indoor temperature T0 at the actual moment and the indoor temperature at the initial moment or the previous moment, and / or based on the compressor operator signal 730, and / or based on the difference between the compressor operator signal 730 at the actual moment and the compressor operator signal 730 at the initial moment or the previous moment), an alarm signal is generated.

[0081] In an embodiment, the control unit 8 is configured to compare the leakage parameter calculated in real time with reference values ​​(e.g., a maximum threshold value and a minimum threshold value) and to generate a diagnostic parameter and / or an alarm signal based on the comparison (e.g., if the leakage parameter exceeds the maximum threshold value or falls below the minimum threshold value).

[0082] In an embodiment, the apparatus 1 includes a four-way valve 6. The four-way valve 6 is connected to the refrigeration circuit between the condenser 2 and the evaporator 4 (specifically, between the refrigerant fluid sensor 72 and the additional refrigerant fluid sensor 74). The four-way valve 6 has a first port connected to the branch of the refrigeration circuit connected to the evaporator 4, the first port being used to receive refrigerant fluid from the evaporator 4 (in cooling mode). The four-way valve 6 has a second port connected to the branch of the refrigeration circuit connected to the condenser 2, the second port being used to send refrigerant fluid to the condenser 2 (in cooling mode). It is observed that in heating mode, the first port releases refrigerant fluid and the second port receives refrigerant fluid. The four-way valve has a third port connected to the inlet of the compressor 5, the third port being used to send refrigerant fluid to the compressor (in cooling mode and in heating mode). The four-way valve 6 has a fourth port connected to the outlet of the compressor 5, the fourth port being used to receive refrigerant fluid from the compressor (in cooling mode and in heating mode). The four-way valve 6 can be operated in a first position to receive refrigerant fluid at the first port and release (compressed) refrigerant fluid at the second port, and can be operated in a second position to receive refrigerant fluid at the second port and release (compressed) refrigerant fluid at the first port. When the four-way valve is in the first position, the device operates in cooling mode, and when the four-way valve is in the second position, the device operates in heating mode.

[0083] The expansion valve 3 can be a mechanical valve or an electronic valve. If the expansion valve is an electronic valve, the control unit 8 is also connected to the expansion valve 3 to control the expansion valve 3. In an embodiment, the control unit 8 controls the expansion valve 3 based on the control parameter 720 detected at the outlet of the evaporator 4 (particularly representing the pressure of the refrigerant fluid at the outlet of the evaporator 4) and based on the indoor temperature T0.

Claims

1. An air conditioning device (1) for a recreational vehicle, comprising: -Refrigerant fluid ； - a refrigeration circuit for circulating the refrigerant fluid, the refrigeration circuit comprising: a condenser (2) which exchanges heat with the external environment and is configured to condense the refrigerant fluid; an expansion valve (3) which is configured to expand the refrigerant fluid; an evaporator (4) which exchanges heat with the interior of the recreational vehicle to be air-conditioned and is configured to evaporate the refrigerant fluid; a compressor (5) which is configured to compress the refrigerant fluid, wherein the evaporator (4) has an inlet connected to the expansion valve (3) and an outlet connected to the compressor (5), and the condenser (2) has an inlet connected to the compressor (5) and an outlet connected to the expansion valve (3); -Leak detection system, including: a refrigerant fluid sensor (72, 74) configured to detect a control parameter (720, 740) representing a physical condition of the refrigerant fluid at the outlet of the evaporator (4) or at the inlet of the condenser (2); A control unit (8) connected to the refrigerant flow sensor (72), characterized in that the control unit (8) is further connected to the compressor (5) and is configured to: receiving in real time the control parameters (720, 740) from the refrigerant fluid sensors (72, 74) and the compressor operating signal (730) from the compressor (5) indicating the operating state of the compressor, Selecting a reference value previously stored in a database according to the compressor operating signal (730), The value of the control parameter (720, 740) is compared with the reference values ​​to generate a diagnostic parameter for evaluating a leak condition.

2. The air conditioning device (1) according to claim 1, wherein: The leakage detection system further comprises an indoor temperature sensor (71) configured to detect an indoor temperature signal (710), the indoor temperature signal representing an indoor temperature (T0) of a room to be air-conditioned, wherein the control unit (8) is configured to receive the indoor temperature signal from the indoor temperature sensor (71) in real time and also select the reference values ​​according to the indoor temperature signal.

3. The air conditioning device (1) according to claim 2, further comprising a memory, wherein The control unit (8) is connected to the memory (81) and is configured to store the control parameter (720) and the compressor operating signal (730) received at the control unit (8) at each of a plurality of successive moments in time in the memory (81).

4. The air conditioning device (1) according to claim 3, wherein: The plurality of successive moments include at least a previous moment that is before the actual moment, and wherein the control unit (8) is configured to compare the control parameter (720) at the actual moment received in real time with the control parameter (720) at the previous moment stored in the memory, and to generate an alarm signal according to a deviation of the control parameter (720) at the actual moment received in real time relative to the control parameter (720) at the previous moment stored in the memory.

5. The air conditioning device (1) according to claim 4, wherein: The control unit (8) is configured to generate the alarm signal if the deviation exceeds a reference threshold, wherein the control unit (8) is configured to select the reference threshold based on the difference between the compressor operation signal (730) at the actual moment received in real time and the compressor operation signal at the previous moment stored in the memory.

6. Air conditioning device (1) according to any one of the preceding claims, wherein The refrigerant fluid sensor (72) is connected to the refrigeration circuit at the outlet of the evaporator (4), and the leakage detection system includes an additional refrigerant fluid sensor (74) connected to the refrigeration circuit at the inlet of the condenser (2) and configured to detect an additional control parameter (740), which represents the physical condition of the refrigerant fluid at the inlet of the condenser (2), wherein the control unit (8) is connected to the additional refrigerant fluid sensor (74) to receive the additional control parameter (740) in real time, and is configured to calculate a differential control parameter as the difference between the control parameter (720) and the additional control parameter (740).

7. The air conditioning device (1) according to claim 6, wherein: The control unit (8) is configured to select differential reference values ​​previously stored in the database according to the compressor operating signal (730), and compare the differential control parameter with the differential reference values ​​to generate the diagnosis parameter.

8. The air conditioning device (1) according to claim 6, wherein: The control unit (8) is configured to calculate a leakage parameter based on the differential control parameter and one or more of the following: a control parameter (720), an additional control parameter (740), an indoor temperature (T0) measured in the room to be air-conditioned, and The leakage parameter is compared to previously memorized minimum and / or maximum thresholds to generate the diagnostic parameter.

9. The air conditioning device (1) according to any one of claims 1 to 5, wherein: The refrigerant fluid sensor (72) is a pressure sensor.

10. The air conditioning device (1) according to claim 9, wherein: The control parameter (720) represents the refrigerant fluid pressure at the outlet of the evaporator (4), and wherein the leak detection system includes an additional refrigerant fluid sensor (74) which is a pressure sensor and is configured to detect an additional control parameter (740) representing the refrigerant fluid pressure at the inlet of the condenser (2).

11. The air conditioning device (1) according to any one of claims 1 to 5, wherein: The leak detection system comprises a power sensor (73) connected to the compressor (5) and configured to measure the power absorbed by the compressor (5), wherein the compressor operating signal (730) represents the power absorbed by the compressor (5).

12. An air conditioning device (1) according to any one of claims 1 to 5, comprising a four-way valve (6) connected to the refrigeration circuit and operable in a first position to operate the device (1) in cooling mode and in a second position to operate the device (1) in heating mode, wherein The control unit (8) is configured to select the reference values ​​also depending on whether the four-way valve (6) is in the first position or in the second position.

13. A method for detecting a refrigerant fluid leak in a refrigeration circuit of a recreational vehicle, wherein: The refrigeration circuit comprises: a condenser (2) for performing heat exchange with the external environment; an expansion valve (3); an evaporator (4) for performing heat exchange with the interior of the recreational vehicle to be air-conditioned; and a compressor (5). The method comprises the following steps: - detecting a control parameter (720) representing the physical condition of the refrigerant fluid at the outlet of the evaporator (4) or at the inlet of the condenser (2); The method is characterized in that the method further comprises the following steps: - receiving the control parameter (720) and the compressor operating signal (730) representing the operating state of the compressor (5) in real time at the control unit (8), - selecting a reference value previously stored in a database according to the compressor operating signal (730), - comparing the value of the control parameter (720) with the reference values ​​and generating diagnostic parameters for assessing a leak condition.

14. The method according to claim 13, wherein The control parameter (720) represents the physical condition of the refrigerant fluid at the outlet of the evaporator, and wherein the method further comprises the steps of detecting an additional control parameter (720) representing the physical condition of the refrigerant fluid at the inlet of the condenser (2), and calculating a differential control parameter which is the difference between the control parameter (720) and the additional control parameter (740).

15. The method according to claim 13 or claim 14, wherein: The control parameter represents the pressure of the refrigerant fluid.

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