Method for pathogen control in vehicle heat pump system

Abstract

Aspects of the present invention relate to a control system (100) for controlling a vehicle heat pump system (200, 300) operable in a heating mode at a first pressure, where the control system (100) includes one or more controllers (110) and is configured to: receive a moisture signal indicative of moisture on a surface of a first heat exchanger (210, 310) of the vehicle heat pump system (200, 300); determining a moisture removal requirement according to the moisture signal; and outputting a control signal (155) for controlling the vehicle heat pump system (200, 300) to operate at a second pressure greater than the first pressure such that a surface of the first heat exchanger (210, 310) is heated to remove moisture therefrom.

Description

Technical Field

[0001] The present disclosure relates to methods for pathogen control in a vehicle heat pump system. Aspects of the present invention relate to control systems, vehicle heat pump systems, vehicles, methods, and computer readable instructions. Background Art

[0002] It is known to provide temperature control to a vehicle cabin by using a heat pump that can operate in a heating mode and a cooling mode. In the heating mode, the heat exchange unit of the heat pump is heated, and air is blown through the heated heat exchange unit into the vehicle cabin to heat the air and thus the vehicle cabin. In the cooling mode, the heat exchange unit is cooled, and the air blown through the heat exchange unit can be cooled. The heat pump system can provide a heating air conditioning function or a cooling air conditioning function to the vehicle.

[0003] A common problem associated with vehicle air conditioning systems is the accumulation of moisture on the surfaces of the heat exchange unit. This is particularly prevalent after the heat exchange unit has been cooled to provide the air conditioning function, due to the low surface temperature of the heat exchange unit compared to its surroundings. Moisture on the surface of the heat exchange unit may provide an environment conducive to bacterial growth. Over time, the use of the air conditioning unit may introduce unpleasant odors associated with bacterial growth as well as pathogens into the vehicle cabin. Therefore, when the air conditioning system is in use, maintenance of the heat pump system may be required to maintain a clean surface of the heat exchange unit to prevent the generation of odors and maintain air quality. In particular, reducing the presence of pathogens is important for vehicle maintenance.

[0004] It is known to attempt to dry the surface of a heat exchange unit without removing the heat exchange unit from the vehicle or manually accessing the location of the heat exchange unit, which in conventional vehicles may be located under the hood. For example, a dedicated heating element, such as a conductive filament heater, may be disposed near the surface of the heat exchange unit to heat and thereby dry the surface. Another approach may involve directing an air flow to carry heat from a heat source, such as a vehicle engine, so that the heated air is blown over the surface of the heat exchange unit. However, these approaches have disadvantages including an increased number of components due to the need for additional dedicated components (e.g., heating elements, fans, blowers, or elements to direct air flow) and manufacturing or installation difficulties, and may interfere with the normal operation of the vehicle temperature control system by blocking the desired air flow direction or interfering with the heat exchange between the heat exchange unit and the surrounding air.

[0005] It is an object of the present invention to address one or more of the disadvantages associated with the prior art. Summary of the invention

[0006] Aspects and embodiments of the present invention provide a control system, a vehicle heat pump system, a vehicle, a method and computer readable instructions as claimed in the appended claims.

[0007] According to one aspect of the present invention, there is provided a control system for controlling a vehicle heat pump system, the vehicle heat pump system being operable in a heating mode at a first pressure, wherein the control system comprises one or more controllers and is configured to:

[0008] receiving a moisture signal indicative of moisture on a surface of a first heat exchanger of a vehicle heat pump system;

[0009] determining moisture removal requirements based on the moisture signal; and

[0010] A control signal is output that controls the vehicle heat pump system to operate at a second pressure greater than the first pressure so that a surface of the first heat exchanger is heated to remove moisture from the surface.

[0011] Advantageously, the control system may control the vehicle heat pump system to operate in a heating mode at a pressure greater than the normal operating pressure to remove moisture from the surface of the first heat exchanger. Advantageously, removing moisture from the surface of the first heat exchanger may inhibit the growth of bacteria or pathogens and maintain a clean vehicle environment. By utilizing the heating mode of the vehicle heat pump system but operating at a second pressure greater than the first pressure, moisture may be removed without requiring dedicated components for removing moisture, such as a heating element. Thus, the vehicle heat pump system may be simplified by not requiring dedicated components for drying the surface of the first heat exchanger.

[0012] In some examples, the control signal controls the vehicle heat pump system to operate in a heating mode at a second pressure so as to heat the surface of the first heat exchanger. Advantageously, an existing mode of the vehicle heat pump system can be used to heat the surface of the first heat exchanger. Heating the surface of the first heat exchanger can inactivate or destroy bacteria or pathogens present on the surface.

[0013] In some examples, the moisture signal indicates at least one of: a temperature or humidity near the first heat exchanger; a usage history of the vehicle heat pump system, the usage history indicating that the vehicle heat pump system has previously been operated in a cooling mode; a user input for removing moisture from a surface of the first heat exchanger; and an identification that a vehicle including the vehicle heat pump system has completed a trip. Advantageously, the control system can control the vehicle heat pump system to operate in a heating mode at a second pressure to remove moisture from a surface of the first heat exchanger when moisture may be present. In some cases, moisture may accumulate on the surface after the first heat exchanger becomes cold during cooling operation. Advantageously, the efficiency of the vehicle heat pump system is maintained by operating to remove moisture only when moisture may be present.

[0014] In some examples, the control system is configured to control the vehicle heat pump system to operate in a heating mode at the second pressure for a predetermined period of time to dry the surface of the first heat exchanger. Advantageously, the vehicle heat pump system can operate in a heating mode at the second pressure for a predetermined time until the surface is dry, and can then be shut down to improve system efficiency.

[0015] In some examples, the control system is configured to control the vehicle heat pump system to operate in a heating mode according to humidity information or temperature information received from at least one sensor until a predetermined humidity or temperature threshold is reached. Advantageously, the vehicle heat pump system does not operate unnecessarily and efficiency is improved.

[0016] In some examples, the control system is configured to, upon determining the requirement to remove moisture, send an output indication to the user requesting user confirmation, and upon receiving the user confirmation, output a control signal to control the vehicle heat pump system to operate at the second pressure. Advantageously, requesting user confirmation based on the moisture signal can allow the user to postpone the operation to a more convenient time, such as after the last trip of the day.

[0017] Furthermore, where the moisture signal is indicative of user input, the output to the user may serve as an additional confirmation step.

[0018] In some examples, the control system is configured to receive a signal indicating that the vehicle has completed a trip, and the control system is configured to postpone output of a control signal to control the vehicle heat pump system to operate at a second pressure until a signal indicating that the vehicle has completed a trip is received. In this way, the system can wait to control the vehicle heat pump system to operate at the second pressure until the vehicle is no longer in use, which can avoid any driver discomfort. In examples where the control system is configured to send an output indication to a user, the control system can postpone outputting the indication to the user requesting user confirmation until a signal indicating that the vehicle has completed a trip is received.

[0019] In some examples, the second pressure is between 14 bar and 20 bar.Advantageously, the temperature of the surface of the first heat exchanger may be increased to at least 50°C or 60°C.

[0020] In some examples, the first pressure is up to 14 bar.

[0021] In some examples, the control system is configured to control the vehicle heat pump system to operate in a heating mode at the second pressure such that the temperature of the surface of the first heat exchanger is increased to at least 50° C. Advantageously, the surface of the first heat exchanger may be effectively dried at 50° C.

[0022] In some examples, the control system is configured to control the vehicle heat pump system to operate in a heating mode at a second pressure such that the temperature of the surface of the first heat exchanger is increased to at least 60° C. In some examples, the temperature is 69° C. Advantageously, bacteria or pathogens present on the surface may be destroyed.

[0023] Advantageously, when the second pressure is 14 bar, a temperature sufficient to remove moisture from the surface of the first heat exchanger can be achieved, and when the second pressure is about 20 bar, a temperature sufficient to directly destroy or inactivate bacteria or pathogens can be achieved.

[0024] According to another aspect of the present invention, there is provided a vehicle heat pump system operable in a heating mode at a first pressure, the vehicle heat pump system comprising: a first heat exchanger; and a control system.

[0025] In some examples, a vehicle heat pump system includes a compressor configured to compress a fluid and thereby heat the fluid.

[0026] In some examples, the vehicle heat pump system includes a control valve configured to control the flow direction of a fluid around the vehicle heat pump system to operate the vehicle heat pump system in a heating mode or a cooling mode. Advantageously, the vehicle heat pump system can operate in both the heating mode and the cooling mode to provide efficient heating and cooling to the vehicle.

[0027] In some examples, the vehicle heat pump system includes a thermal expansion valve connected between the compressor and the first heat exchanger and configured to control a flow rate of the compressed fluid to control expansion of the compressed fluid to cool the fluid in a cooling mode.

[0028] In some examples, the vehicle heat pump system includes a second heat exchanger coupled between the compressor and the thermal expansion valve.

[0029] In some examples, in the heating mode, the first heat exchanger may operate as a condenser, and in the cooling mode, the first heat exchanger may operate as an evaporator.

[0030] In some examples, in the heating mode, the second heat exchanger may operate as an evaporator, and in the cooling mode, the second heat exchanger may operate as a condenser.

[0031] In some examples, a vehicle heat pump system includes an accumulator connected between the first heat exchanger and the compressor.

[0032] In some examples, the fluid is a refrigerant.

[0033] In some examples, the thermal expansion valve is configured to cool the fluid via a throttling phenomenon.

[0034] In some examples, the control system is configured to output a control signal that controls the vehicle heat pump system to operate in a heating mode at a second pressure so that the temperature of the surface of the first heat exchanger is increased to at least 50° C. Advantageously, the surface of the first heat exchanger can be effectively dried at 50° C.

[0035] In some examples, the control system is configured to output a control signal that controls the vehicle heat pump system to operate in a heating mode at a second pressure so that the temperature of the surface of the first heat exchanger is increased to at least 60° C. In some examples, the temperature is 69° C. Advantageously, bacteria or pathogens present on the surface can be destroyed.

[0036] In some examples, the vehicle heat pump system includes a control valve configured to control the flow direction of the fluid around the vehicle heat pump system, thereby operating the vehicle heat pump system in a heating mode or a cooling mode. The control valve includes a three-way valve configured to selectively connect the compressor and the first heat exchanger via a thermal expansion valve, and is configured to selectively connect the compressor and the second heat exchanger. The three-way valve is configured to selectively guide the fluid to bypass the second heat exchanger so that the hot fluid circulates through the compressor, the three-way valve, the thermal expansion valve, and the first heat exchanger. Advantageously, by controlling the flow direction of the fluid around the vehicle heat pump system to heat or cool the first heat exchanger, the vehicle heat pump system can operate in a heating mode or a cooling mode.

[0037] In some examples, the vehicle heat pump system includes a valve that can be operated between open or restricted to selectively contain fluid in the first heat exchanger; and the control system is configured to output a control signal in response to receiving the moisture signal, which controls the valve to be restricted so as to contain the hot fluid in the first heat exchanger. Advantageously, the hot refrigerant can circulate through the first heat exchanger without being cooled by the second heat exchanger. Therefore, the efficiency of operating the vehicle heat pump system in the heating mode at the second pressure can be improved.

[0038] In some examples, the valve includes a second thermal expansion valve.

[0039] In some examples, the vehicle heat pump system includes at least one of a temperature sensor configured to detect a temperature near the first heat exchanger or a humidity sensor configured to detect humidity near the first heat exchanger; and the moisture signal includes at least one of the detected temperature or the detected humidity. Advantageously, the vehicle heat pump system can determine when moisture is present on the surface of the first heat exchanger, and thus operate in a heating mode at a second pressure when necessary. In addition, the vehicle heat pump system can determine when moisture has been successfully removed or a target temperature of the surface of the first heat exchanger has been reached, and thus stop operating.

[0040] In some examples, the vehicle heat pump system includes a blower configured to blow air across a surface of the first heat exchanger; and the control system is configured to control the fan to operate at a low speed to blow air across the surface of the first heat exchanger when it is determined to dry the surface of the first heat exchanger. Advantageously, moisture in the air around the first heat exchanger can be dissipated, and the removal of moisture from the surface can be accelerated while reducing power consumption of the blower.

[0041] According to another aspect of the present invention, a vehicle including a control system or a vehicle heat pump system is provided.

[0042] According to another aspect of the present invention, there is provided a method for removing moisture from a surface of a first heat exchanger of a vehicle heat pump system, the vehicle heat pump system being operable in a heating mode at a first pressure, the method comprising:

[0043] receiving a moisture signal indicative of moisture on a surface of the first heat exchanger;

[0044] determining moisture removal requirements based on the moisture signal; and

[0045] A control signal is output that controls the vehicle heat pump system to operate at a second pressure greater than the first pressure so that a surface of the first heat exchanger is heated to remove moisture from the surface.

[0046] In some examples, the second pressure is between 14 bar and 20 bar.

[0047] In some examples, the moisture signal indicates at least one of: a usage history of the vehicle heat pump system indicating that the vehicle heat pump system has previously been operated in a cooling mode; a user input for removing moisture from a surface of the first heat exchanger; and an identification that a vehicle including the vehicle heat pump system has completed a trip. Advantageously, the control system can control the vehicle heat pump system to operate in a heating mode at a second pressure to remove moisture from a surface of the first heat exchanger when moisture may be present. In some cases, moisture may accumulate on the surface after the first heat exchanger cools during cooling operation. Advantageously, the efficiency of the vehicle heat pump system is maintained by operating to remove moisture only when moisture may be present.

[0048] In some examples, the method includes detecting a temperature near the first heat exchanger or humidity near the first heat exchanger; and the moisture signal includes at least one of the detected temperature or the detected humidity. Advantageously, the vehicle heat pump system can determine when moisture is present on the surface of the first heat exchanger, and thus operate in a heating mode at a second pressure when necessary. In addition, the vehicle heat pump system can determine when moisture has been successfully removed or a target temperature of the surface of the first heat exchanger has been reached, and thus stop operating.

[0049] In some examples, the method includes controlling the vehicle heat pump system to operate in a heating mode for a predetermined period of time to dry a surface of the first heat exchanger.

[0050] In some examples, the method includes controlling the vehicle heat pump system to operate in a heating mode until a predetermined humidity or temperature threshold is reached.

[0051] In some examples, the method includes: controlling the vehicle heat pump system to operate in a heating mode at a second pressure so that the surface temperature of the first heat exchanger is increased to at least 50° C.; or controlling the vehicle heat pump system to operate in a heating mode at a second pressure so that the surface temperature of the first heat exchanger is increased to at least 60° C. Advantageously, when the surface is heated to 50° C., moisture can be effectively removed from the surface. Advantageously, when the surface is heated to at least 60° C., bacteria or pathogens present on the surface of the first heat exchanger can be destroyed or inactivated.

[0052] According to another aspect of the present invention, there is provided computer readable instructions which, when executed by a computer, are arranged to perform the method.

[0053] It is expressly intended that the various aspects, embodiments, examples and alternatives set forth in the preceding paragraphs, in the claims and / or in the following description and drawings, and in particular their individual features, may be employed independently or in any combination within the scope of the present application. That is, all embodiments and / or features of any embodiment may be combined in any manner and / or combination, unless such features are incompatible. Applicants reserve the right to change any originally filed claim or to file any new claim accordingly, including the right to amend any originally filed claim to be subordinate to any other claim and / or to incorporate any features of any other claim, even though protection was not originally claimed in this manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] One or more embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0055] Figure 1 shows a block diagram representation of a control system according to an embodiment of the present invention;

[0056] Figure 2 shows a block diagram representation of a vehicle heat pump system according to an embodiment of the present invention;

[0057] Figure 3 shows a block diagram representation of a vehicle heat pump system according to an embodiment of the present invention;

[0058] Figure 4A flow chart showing a method for drying a surface of a heat exchanger of a vehicle heat pump system according to an embodiment of the present invention is shown; and

[0059] Figure 5 A vehicle according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0060] The present disclosure relates to a vehicle heat pump system and a method of operating the vehicle heat pump system to dry the surface of a heat exchanger. Figure 2 and Figure 3 Described in more detail, a heat pump typically includes a compressor, two heat exchange units that can operate as a condenser and an evaporator, and at least one expansion device. A fluid, such as a refrigerant, is compressed by the compressor and then passes through one of the heat exchange units, the expansion device, the second heat exchange unit, and returns to the compressor. During this process, the temperature of the fluid changes due to the throttling effect that occurs in the expansion device and the compression of the fluid that occurs in the compressor. The flow direction of the fluid can be reversible, or the flow route of the fluid can be changed to switch between a heating mode and a cooling mode, so that the heat exchange unit near the air flow entering the vehicle cabin is heated or cooled by the fluid passing through the heat exchange unit, thereby heating or cooling the vehicle cabin.

[0061] This article refers to the attached Figure 1 A control system 100 according to an embodiment of the present invention is described. Figure 1 A block diagram representation of a control system 100 according to an embodiment of the present invention is shown.

[0062] Reference Figure 1 , the control system 100 includes one or more controllers 110. In use, the control system 100 may be communicatively coupled to a vehicle heat pump system operable in a heating mode at a first pressure, and the control system 100 may be configured to control the operation of the vehicle heat pump system.

[0063] The control system 100 is configured to receive a moisture signal indicating moisture on the surface of a first heat exchanger of a vehicle heat pump system. A heat exchanger may also be referred to as a heat exchange unit. The control system 100 may determine the requirement to remove moisture from the surface of the first heat exchanger based on the moisture signal. Then, the control system 100 may output a control signal 155 that controls the vehicle heat pump system to operate in a heating mode at a second pressure. The second pressure may be higher than the first pressure. In some examples, the second pressure may be between 14 bar and 20 bar. As the maximum operating pressure for heating or cooling a vehicle compartment during normal operation of a vehicle heat pump system, the first pressure may be approximately 14 bar, but it should be understood that the vehicle heat pump system may also operate at other pressures depending on the required heating or cooling.

[0064] It should be understood that the maximum pressure that can be achieved by the system may be limited by the physical constraints of the system components, as described in relation to Figure 2 discussed.

[0065] However, the control system 100 can control the vehicle heat pump system to operate in the heating mode at a second pressure that is greater than the normal operating pressure of the system in the normal heating mode for heating the cabin. The control system 100 can also receive information 165 indicating a detected temperature or humidity near the first heat exchanger from one or more sensors 160, and can determine a requirement to remove moisture based on the received information 165. In some examples, the temperature or humidity information can be included in the moisture signal.

[0066] Operating the vehicle heat pump system in heating mode at a second pressure can increase the temperature of the surface of the first heat exchanger to a temperature higher than the usual operating temperature sufficient to remove moisture from the surface of the first heat exchanger. The temperature of the surface of the first heat exchanger is related to the pressure of the vehicle heat pump system in heating mode. For example, if the vehicle heat pump system is operated in heating mode at 14 bar, the temperature of the surface of the first heat exchanger can be increased to approximately 50°C. In some examples, if the vehicle heat pump system is operated in heating mode at 20 bar, the temperature of the surface of the first heat exchanger can be increased to approximately 60°C or 69°C. During normal use of the vehicle heat pump system, the vehicle heat pump system can operate at a first pressure to heat the cabin. In some examples, the first pressure can be as high as 14 bar. Advantageously, by heating the surface of the first heat exchanger to approximately 50°C, moisture can be removed from the surface of the first heat exchanger by evaporation. It should be understood that removing moisture from the surface of the heat exchanger inhibits bacterial growth on the surface of the heat exchanger and can also reduce pathogen load. Advantageously, by heating the surface of the first heat exchanger to approximately 60° C. or 69° C., moisture may be removed from the surface of the first heat exchanger by evaporation, and bacteria or pathogens present in the air on or near the surface of the first heat exchanger may be inactivated or destroyed. The pressure of the vehicle heat pump system may be controlled by at least one of the compressor and the expansion device.

[0067] like Figure 1 The control system 100 shown includes a controller 110, but it should be understood that this is illustrative only. The controller 110 includes a processing device 120 and a storage device 130. The processing device 120 can be one or more electronic processing devices 120 operable to execute computer-readable instructions. The storage device 130 can be one or more storage devices 130. The storage device 130 is electrically coupled to the processing device 120. The storage device 130 is configured to store instructions, and the processing device 120 is configured to access the storage device 130 and execute the instructions stored on the storage device 130.

[0068] The controller 110 includes an input device 140 and an output device 150. The input device 140 may include an electrical input 140 of the controller 110. The output device 150 may include an electrical output of the controller 110. The input 140 is arranged to receive a moisture signal. The input 140 may also be arranged to receive at least one of a temperature signal 165 or a humidity signal 165 from a temperature sensor 160 or a humidity sensor 160.

[0069] The moisture signal, the temperature signal 165, and the humidity signal 165 may be electrical signals indicating moisture present on the surface of the first heat exchanger, the temperature detected by the temperature sensor 160, and the humidity detected by the humidity sensor 160, respectively. Although the sensor 160 is shown as being external to the controller 110, the controller 110 may include the sensor 160 as an integrated module. The output terminal 150 is arranged to output a control signal 155 for controlling the vehicle heat pump system to operate in a heating mode at a second pressure. The control signal 155 may be output by the output terminal 150 to the vehicle heat pump system.

[0070] The controller 110 may also communicate with one or more additional sensors ( Figure 1 The controller 110 may be communicatively coupled to a vehicle control system (not shown) or a vehicle communication network to determine information about the vehicle heat pump system. The controller 110 may also be communicatively coupled to a vehicle control system, such as a system including a vehicle communication bus, which may relay information and control signals between various components and systems of the vehicle. For example, the controller 110 may receive a moisture signal via the vehicle control system. The controller 110 may also receive control signals corresponding to user inputs on a user interface module in the vehicle.

[0071] The moisture signal may indicate moisture on the surface of the first heat exchanger of the vehicle heat pump system. In some examples, the moisture signal indicates a usage history of the vehicle heat pump system, which indicates that the vehicle heat pump system has previously been operated in a cooling mode. That is, the vehicle heat pump system may be operated in a cooling mode to cool the cabin and provide air conditioning functions to the cabin. During the cooling mode, the first heat exchanger is cooled by a cold fluid passing through the first heat exchanger. Since the first heat exchanger is colder than the surrounding air, moisture may accumulate on the surface of the first heat exchanger. Therefore, if it is determined that the vehicle heat pump system has been operated in a cooling mode, the control system 100 may determine to operate the vehicle heat pump system in a heating mode at a second pressure to remove moisture from the surface of the first heat exchanger and / or eliminate bacteria and pathogens on the surface of the first heat exchanger. Removing moisture from the surface of the heat exchanger can reduce bacterial growth on the surface of the heat exchanger, and bacterial growth benefits from a humid environment. For example, when it is determined that the vehicle heat pump system has been operated in a cooling mode for a predetermined time, it may be determined to start a drying process. The control system 100 may determine to operate the vehicle heat pump system in the heating mode at the second pressure when it is determined that the vehicle has completed the trip so as not to interfere with the heating function or cooling function desired by the user.

[0072] In another example, a moisture signal may be received according to a user's request to dry the surface of the first heat exchanger. The moisture signal may include a user's request to dry the surface of the first heat exchanger. In some examples, the moisture signal may be any indication signal that is not a user request, and in response to receiving the indication signal, the control system 100 may output an indication to the user, recommending disinfection of the vehicle heat pump system or the vehicle HVAC system to reduce the presence of bacteria or pathogens. To this end, the control system 100 may output an indication of a process corresponding to a process for removing moisture from the vehicle heat pump system. The user may confirm that the process should be started. Then, the control system outputs a control signal to the vehicle heat pump system according to the user confirmation. In some examples, a recommendation may be provided to the user based on a time after a previous execution of the drying process exceeding a predetermined threshold, or based on the use of the vehicle heat pump system in a cooling mode. The user may also decide to start the drying process without outputting a recommendation to start the drying process. Alternatively or additionally, the control system 100 may determine to remove moisture from the surface of the first heat exchanger based on the temperature or humidity information 165 received from at least one sensor 160. For example, at least one sensor 160 may be disposed near the first heat exchanger and may measure at least one of temperature or humidity near the first heat exchanger. If the measured temperature or humidity exceeds a predetermined threshold, a requirement to remove moisture from the first heat exchanger may be determined.

[0073] In some examples, the control system may determine a requirement to remove moisture from the first heat exchanger while the vehicle is still in use. While the vehicle is in use, the user may wish to maintain the temperature of the vehicle heat pump until the trip is complete. Thus, the control signal may be configured to receive a signal that the trip is complete and then output the control signal upon receipt of the signal. In other words, the control system may be configured to postpone output of the control signal that controls the vehicle heat pump system to operate at the second pressure until a signal is received indicating that the vehicle has completed the trip.

[0074] In some examples, when a requirement to remove moisture from the surface of the first heat exchanger is determined, the vehicle heat pump system can operate in a heating mode at the second pressure for a predetermined time. In another example, the vehicle heat pump system can operate in a heating mode at the second pressure until the temperature or humidity value measured by the at least one sensor 160 reaches a predetermined value.

[0075] Figure 2 FIG. 2 shows a vehicle heat pump system 200 according to an embodiment of the present invention. The vehicle heat pump system 200 may include Figure 1 The control system 100 shown, although Figure 2 For example, the vehicle heat pump system 200 may be Figure 1 Operates under the control of the control system 100.

[0076] The vehicle heat pump system 200 includes a first heat exchanger 210, a second heat exchanger 220, an expansion device 230, an accumulator 240, a compressor 250, and a control valve 260. However, it should be understood that not all of these components are required, and one or more components may be omitted. For example, at least the accumulator 240 may be omitted. A fluid such as a refrigerant or a coolant may be conducted around the vehicle heat pump system 200 via a conduit 270. Air from a source inside and outside the vehicle including the vehicle heat pump system 200 may be drawn through the vehicle heat pump system 200 to heat or cool the air.

[0077] The first heat exchanger 210 and the second heat exchanger 220 may include a heat exchange unit configured to exchange heat energy with the surrounding air. Heat exchangers 210, 220 may also be referred to as heat exchange units, heat exchangers or heat exchange units. It should be understood that any suitable type of heat exchanger may be used, including shell and tube heat exchangers, plate heat exchangers, plate shell heat exchangers, plate fin heat exchangers, fin tube heat exchangers, pillow plate heat exchangers, microchannel heat exchangers and coil heat exchangers. The selection of the type of heat exchanger to be used may be determined based on the maximum operating temperature or pressure of the heat exchanger. The first heat exchanger 210 and the second heat exchanger 220 are configured to control fluid passing through the first heat exchanger 210 and the second heat exchanger 220, and promote the heat energy exchange between the fluid in the first heat exchanger 210 and the second heat exchanger 220 and the surrounding air.

[0078] The compressor 250 is configured to compress the fluid. The compressor 250 may include any suitable type of compressor. The compressor 250 may be configured to compress the fluid to a first pressure during normal operation of the vehicle heat pump system 200 in a heating mode or a cooling mode. In some examples, the first pressure may be as high as 14 bar. However, the compressor 250 may be configured to compress the fluid to a pressure lower than the first pressure during operation, or it may be considered that the first pressure may vary according to the temperature requirements of the vehicle heat pump system 200 based on the control of the desired cabin temperature by the user or the vehicle. The pressure mentioned herein is the pressure of the fluid in the first heat exchanger 210. It should be understood that, as will be discussed below, the pressure of the fluid will vary between different positions in the vehicle heat pump system 200 due to the operation of the vehicle heat pump system 200 to realize the heating and cooling functions. The pressure of the vehicle heat pump system 200 may be determined by the temperature required to remove moisture from the surface of the first heat exchanger 210. That is, if it is desired to remove moisture from the surface of the first heat exchanger 210, the target temperature to be achieved at the surface of the first heat exchanger 210 may be 50°C and the pressure may be approximately 14 bar, but if it is desired to directly destroy pathogens on the surface of the first heat exchanger 210, the desired temperature may be 69°C and the pressure may be approximately 20 bar.

[0079] The control valve 260 includes a valve configured to control the flow direction of the fluid around the vehicle heat pump system 200. In some examples, the control valve 260 may include a three-way valve, a T valve, or a reversing valve. The control valve 260 is configured to be Figure 1The flow direction of the fluid around the vehicle heat pump system 200 is controlled under the control of the control system 100. The flow direction of the fluid around the vehicle heat pump system 200 determines whether the vehicle heat pump system 200 is operated in a heating mode or a cooling mode. That is, when the fluid is guided along a first direction around the vehicle heat pump system 200, the first heat exchanger 210 becomes hot due to the hot fluid passing through the first heat exchanger 210, and thus the first heat exchanger 210 is heated by the fan (by the fan). Figure 2 The air blowing through the first heat exchanger (indicated by the arrow in FIG. 21 ) can be heated and provided to the passenger compartment to warm up the passenger compartment. The control valve 260 can change the flow direction of the fluid to a second flow direction, in which the cold fluid passes through the first heat exchanger 210, and the air blowing through the first heat exchanger 210 is cooled and provided to the passenger compartment to cool the passenger compartment. It should be understood that Figure 2 The conduit 270 and the control valve 260 may show a simplified configuration of the fluid path, and the control valve 260 may change the flow direction of the fluid around the vehicle heat pump system 200 by directing the fluid to other (not shown) conduits. However, it should be understood that the present disclosure is not limited to Figure 2 The exact structure of the vehicle heat pump system 200 shown, and any heat pump system operable in both a heating mode and a cooling mode, may be used to implement the present invention.

[0080] The accumulator 240 comprises a vessel or container to hold the fluid awaiting compression in the compressor 250 .

[0081] The expansion device 230 is configured to control the flow rate of the fluid through the expansion device 230 and produce a cooling effect on the fluid through a throttling effect. The expansion device 230 may alternatively be referred to as a thermal expansion valve or a throttling device.

[0082] For example, the expansion device 230 may include a capillary tube or a pressure control valve. The expansion device 230 may restrict the flow of the fluid through the expansion device 230 to reduce the pressure of the fluid and allow the fluid to expand isenthalpically from the liquid phase to the gas phase at a lower temperature. Therefore, the temperature of the fluid decreases as the fluid passes through the expansion device 230.

[0083] One or more conduits 270 are provided to connect between the first heat exchanger 210, the second heat exchanger 220, the expansion device 230, the accumulator 240, the compressor 250, and the control valve 260. The conduit 270 may include a continuous channel or multiple channel portions, and may be configured to contain a fluid and control the flow of the fluid between the components of the vehicle heat pump system 200.

[0084] The basic operation of the vehicle heat pump system 200 in the cooling mode is as follows. In the cooling mode, the fluid may be around Figure 2The vehicle heat pump system 200 flows counterclockwise. First, the fluid is compressed into a high-pressure, high-temperature gas in the compressor 250. The fluid passes through the control valve 260 to the second heat exchanger 220, which acts as a condenser in the cooling mode. The fluid exchanges heat energy with the surrounding air and is partially cooled and condensed into a liquid high-pressure fluid. The high-pressure liquid fluid passes through the expansion device 230 and at least a portion of the fluid undergoes isenthalpic expansion and returns to the gaseous state. Due to the flow restriction of the expansion device 230 discussed above and the resulting pressure difference, the temperature of the fluid decreases as the fluid passes through the expansion device 230. The fluid may undergo an adiabatic flash at this stage. The cold fluid (which may include a liquid-gas mixture) then passes through the first heat exchanger 210 and exchanges heat energy with the surrounding air. A fan may blow air across the surface of the first heat exchanger 210 to provide cool air to the cabin, such as Figure 2 Indicated by the arrow in . The first heat exchanger 210 acts as an evaporator in the cooling mode, and the fluid passing through the first heat exchanger evaporates into a gaseous state. Then, the fluid returns to the compressor 250 via the accumulator 240 and the cycle starts again.

[0085] During cooling mode, moisture may accumulate on the surface of the first heat exchanger 210 due to the temperature being lower than the temperature of the surrounding air. Due to the humid environment, moisture may accumulate and cause bacterial growth, and the associated increase in odors and pathogens may be undesirable. Therefore, the control system 100 or the vehicle heat pump system 200 may receive a moisture signal indicative of moisture on the surface of the first heat exchanger 210, and a requirement to remove moisture may be determined. When it is determined that moisture is to be removed, the vehicle heat pump system 200 may operate in a heating mode at a second pressure, thereby heating the surface of the first heat exchanger 210 to remove moisture. As discussed above, the second pressure may be greater than the first pressure, which is the normal operating pressure of the vehicle heat pump system 200, and thus a high temperature of the surface of the first heat exchanger 210 may be achieved. In some examples, the second pressure may be between 14 bar and 20 bar, which may correspond to a surface temperature of the first heat exchanger 210 between 50°C and 69°C. As described above with reference to Figure 1 As illustrated, determination of a moisture signal or requirement to remove moisture may be based on a number of factors including a history of vehicle heat pump system 200 usage in a cooling mode, recognition of an end of vehicle trip, a user request, a scheduled maintenance cycle, or temperature or humidity information.

[0086] Figure 2 The vehicle heat pump system 200 may include a second expansion device 235. The second expansion device 235 may be similar or identical to the first expansion device 230 and may be configured such that Figure 2The vehicle heat pump system 200 can be operated in either direction to operate the vehicle heat pump system 200 in a heating mode or a cooling mode. That is, when the vehicle heat pump system 200 is operated in a heating mode, the second expansion device 235 can perform operations similar to the operation of the first expansion device 230 in a cooling mode described above.

[0087] To operate the vehicle heat pump system 200 in the heating mode, the flow direction of the fluid around the vehicle heat pump system 200 is reversed by the control valve 260. As explained above, it should be understood that Figure 2 A simplified configuration of the control valve 260 and conduit 270 may be shown to aid understanding, and any alternative configuration of a heat pump system operable in both cooling and heating modes may be used. Figure 2 In the example of FIG. 2 , the fluid may flow clockwise around the vehicle heat pump system 200 in the heating mode: from the compressor 250 to the second expansion device 235, to the first heat exchanger 210 to heat the first heat exchanger 210, through the expansion device 230 to the second heat exchanger 220, through the control valve 260 and back to the compressor 250. It should be understood that in this case, the roles of the first heat exchanger 210 and the second heat exchanger 220 are reversed compared to the operation of the vehicle heat pump system 200 in the cooling mode. In this case, the second expansion device 235 may perform operations similar to those of the first expansion device 230 in the cooling mode and ensure condensation of the fluid upstream of the accumulator 240.

[0088] The vehicle heat pump system 200 or the control system 100 can determine the requirement to dry the surface of the first heat exchanger 210 based on the moisture signal indicating the presence of moisture on the surface. In order to dry the surface, the vehicle heat pump system 200 can be operated in a heating mode at a second pressure that is higher than the normal operating pressure of the vehicle heat pump system 200. During the operation of the vehicle heat pump system 200 in the heating mode at the second pressure to dry the surface of the first heat exchanger 210, a blower (not shown) can be optionally controlled to blow air across the surface of the first heat exchanger 210. The air flow delivered by the blower can dissipate moisture from the surrounding environment of the first heat exchanger 210, and thereby accelerate the removal of moisture from the surface of the first heat exchanger 210 in combination with the heating provided by the operation of the vehicle heat pump system 200 as discussed above. The operation of the blower can be determined by the surface temperature requirement of the first heat exchanger 210. The blower can be controlled by the control system 100, or more specifically by the controller 110. A cooling fan or blower (not shown) may also be provided and arranged to direct air to the surface of the second heat exchanger 220 .

[0089] Figure 31 shows a block diagram representation of a vehicle heat pump system 300 according to an embodiment of the present invention. The vehicle heat pump system 300 and Figure 2 The vehicle heat pump system 200 operates similarly, and therefore a detailed description of the common components is omitted. Figure 2 and Figure 3 In a conventional heat exchanger, the heat exchanger, compressor, expansion device and accumulator operate in the same manner.

[0090] Figure 3 The vehicle heat pump system 300 and Figure 2 The vehicle heat pump system 200 of FIG. 300 differs in that an alternative path for the fluid to circulate in the heating cycle is provided via the conduit 370 . In addition, the vehicle heat pump system 300 further includes a check valve 380 and a second expansion device 335 . Figure 3 The check valve 380 may include a one-way valve configured to allow fluid to flow in one direction and prevent fluid from flowing in the opposite direction. Figure 3 A second expansion device 335 is shown in FIG, but the second expansion device 335 may be omitted or an alternative valve may be provided in the same location, as discussed below.

[0091] The vehicle heat pump system 300 may be similar to Figure 2 The vehicle heat pump system 200 operates in a cooling mode, wherein fluid flows from the compressor 350 to the control valve 360, the second heat exchanger 320, the check valve 380, the expansion device 330, the first heat exchanger 310, and the accumulator 340 before returning to the compressor 350. As explained above, the second expansion device 335 may be omitted.

[0092] The control valve 360 ​​can control the flow direction of the fluid to operate the vehicle heat pump system 300 in the heating mode, as indicated by the arrow provided showing the route of the conduit 370 passing through the vehicle heat pump system 300. In this example, the fluid does not pass through the second heat exchanger 320, but circulates between the compressor and the first heat exchanger 310. Therefore, the hot fluid can be continuously and effectively provided to the first heat exchanger 310, thereby heating the surface of the first heat exchanger 310 to remove moisture, and thereby drying the surface of the first heat exchanger 310. The fluid can be prevented from entering the second heat exchanger 320 by the check valve 380 and the control valve 360. The vehicle heat pump system 300 can, for example, receive a moisture signal indicating moisture on the surface of the first heat exchanger 310 as previously described to operate in the heating mode with a second pressure to dry the surface of the first heat exchanger 310.

[0093] Figure 3The vehicle heat pump system 300 also includes a second expansion device 335. Although an expansion device similar to the first expansion device 330 is shown, it should be understood that any other component (such as a valve suitable for restricting the flow of fluid) can be used in place of the second expansion device 335. The second expansion device 335 is configured to restrict the flow of fluid leaving the first heat exchanger 310, thereby containing the hot fluid within the first heat exchanger 310. Advantageously, by providing the second expansion device 335, the energy consumption of the vehicle heat pump system 300 can be improved, which operates in a heating mode at a second pressure to dry the surface of the first heat exchanger 310 because the hot fluid can be contained in the first heat exchanger 310. Therefore, the need to continuously pump fluid around the vehicle heat pump system 300 is reduced, while the temperature of the first heat exchanger 310 can be maintained at an elevated temperature. As previously discussed, in some examples, when the pressure of the fluid in the vehicle heat pump system 300 is about 14 bar, the surface of the first heat exchanger 310 is heated to at least 50° C., and when the pressure is about 20 bar, the surface of the first heat exchanger 310 is heated to at least 60° C. In some examples, when the pressure is about 20 bar, the surface of the first heat exchanger 310 is heated to about 69° C.

[0094] Figure 4 A method 400 according to an embodiment of the present invention is shown. The method 400 is a vehicle 500 (e.g. Figure 5 The method 400 is a method for removing moisture from a surface of a first heat exchanger of a vehicle heat pump system that can be operated in a heating mode at a first pressure. The method 400 can be performed by Figure 1 The control system 100 shown in FIG. 1 may be executed by Figure 2 or Figure 3 The vehicle heat pump system 200, 300 is implemented.

[0095] Specifically, the storage device 130 may include computer readable instructions that, when executed by the controller 110, perform the method 400 according to an embodiment of the present invention. It should be understood that the method 400 may be executed by Figure 2 or Figure 3 The vehicle heat pump systems 200 , 300 are shown to perform, but the method 400 is not limited thereto.

[0096] The method 400 may be performed by any heat pump system operable in a heating mode.

[0097] At block 410, the method includes receiving a moisture signal indicating moisture on the surface of the first heat exchanger. In some examples, the moisture signal indicates a usage history of the vehicle heat pump system, which indicates that the vehicle heat pump system has previously been operated in cooling mode. That is, the vehicle heat pump system can be operated in cooling mode to cool the cabin and provide air conditioning functions to the cabin. During cooling mode, the first heat exchanger is cooled by a cold fluid passing through the first heat exchanger. Since the first heat exchanger is colder than the surrounding air, moisture may accumulate on the surface of the first heat exchanger. In some examples, the moisture signal may indicate that the vehicle heat pump system has been operated in cooling mode for a predetermined time. The usage history may also include the number of times the vehicle heat pump has been operated in cooling mode. In some examples, the moisture signal may also indicate that the vehicle heat pump system is no longer operating, or that the vehicle trip has ended.

[0098] In another example, a moisture signal may be received based on a user's request to dry the surface of the first heat exchanger. The moisture signal may include a user's request to dry the surface of the first heat exchanger. In some examples, the moisture signal may be any of the above-mentioned indication signals, and in response to receiving the indication signal, the control system may output to the user an indication suggesting that moisture be removed from the vehicle heat pump system. The user may confirm that the drying process should be initiated. In some examples, a suggestion may be provided to the user based on a time after a previous execution of the drying process exceeding a predetermined threshold, or based on the use of the vehicle heat pump system in cooling mode. The user may also decide to initiate the drying process without outputting a suggestion to do so. In some examples, the moisture signal may be received based on a predefined maintenance plan.

[0099] Alternatively or additionally, the moisture signal may be received based on temperature or humidity information received from at least one sensor. For example, at least one sensor may be disposed near the first heat exchanger and may measure at least one of the temperature or humidity near the first heat exchanger. If the measured temperature or humidity exceeds a predetermined threshold, the moisture signal may be received.

[0100] The moisture signal may be received from a vehicle control system, a vehicle user interface, or from at least one sensor.Alternatively, a controller of a control module of the vehicle heat pump system may determine the moisture signal itself.

[0101] At block 420, the method includes determining a requirement to remove moisture based on the moisture signal. The method may include identifying the moisture signal and determining that moisture may be present on the surface of the first heat exchanger based on the moisture signal. The method may include receiving the moisture signal, the moisture signal including information associated with the vehicle usage history, temperature or humidity information, or information corresponding to user input at block 410 as described above, and determining a requirement to dry the surface of the first heat exchanger based on the received information. For example, the method may include determining that moisture may be present on the surface of the first heat exchanger based on the moisture signal. For example, the method may include comparing the detected temperature or humidity to a threshold value.

[0102] At block 430, the method includes outputting a control signal that controls the vehicle heat pump system to operate in a heating mode at a second pressure greater than the first pressure so that the surface of the first heat exchanger is heated to remove moisture from the surface. The method may include controlling a compressor and / or a control valve of the vehicle heat pump system to compress the fluid to the second pressure and control the flow direction of the fluid around the vehicle heat pump system to operate the vehicle heat pump system in the heating mode and pass the hot fluid through the first heat exchanger.

[0103] The method may include operating the vehicle heat pump system in the heating mode at the second pressure for a predetermined time.Alternatively or additionally, the vehicle heat pump system may operate in the heating mode at the second pressure until a temperature or humidity measurement proximate the first heat exchanger reaches a predetermined value.

[0104] The method may include operating a fan of the vehicle heat pump system to blow air across a surface of the first heat exchanger to dissipate moisture in the air surrounding the first heat exchanger.

[0105] The method may include determining to operate the vehicle heat pump system in a heating mode at a second pressure upon determining that the vehicle has completed a trip so as not to interfere with a heating function or a cooling function desired by a user.

[0106] In some examples, the second pressure is between 14 bar and 20 bar, and the first pressure is up to 14 bar. In some examples, the surface of the first heat exchanger is heated to at least 50° C., at least 60° C., or at least 69° C. At 50° C., the surface of the first heat exchanger is effectively dried. In some examples, at 60° C. or 69° C., bacteria or pathogens present on or around the surface of the first heat exchanger can be destroyed or inactivated.

[0107] After the vehicle heat pump system operates in the heating mode at the second pressure for a predetermined time or until the temperature or humidity value reaches a predetermined threshold, the method ends. Figure 4 Method 400 may occur after the user has exited the vehicle.

[0108] Figure 5 A vehicle 500 is shown according to an embodiment of the present invention. Figure 5 The vehicle 500 may include Figure 1 Control system 100, Figure 2 Vehicle heat pump system 200 or Figure 3 The vehicle heat pump system 300 of the vehicle 500 can be implemented Figure 4 Method 400.

[0109] The vehicle 500 may include a heat pump system and one or more cabins in which users may move. The vehicle heat pump system may be used to heat or cool the cabin based on whether the vehicle heat pump system is operating in a heating mode or a cooling mode. The vehicle heat pump system may be operated in a heating mode at a pressure higher than a normal operating pressure to dry the surface of the first heat exchanger.

[0110] Advantageously, it is not necessary to include additional components in the vehicle or vehicle heat pump system to implement the present invention to dry the surface of the first heat exchanger, which can be applied to any existing vehicle heat pump system. Therefore, manufacturing, installation and maintenance are simplified. In addition, the normal operation of the vehicle heat pump system is not affected by the presence of additional components as in some conventional methods. The surface of the first heat exchanger can be heated to effectively dry the surface and prevent or reduce the growth of bacteria on the surface, which may cause undesirable odors in the cabin. In addition, by operating the vehicle heat pump system at a higher pressure, the surface of the first heat exchanger can be heated to a temperature higher than normal operation and sufficient to destroy or inactivate bacteria or pathogens on or near the surface. When it is determined that moisture may exist on the surface based on various factors, it can be determined to dry the surface, and the drying process can be performed after the trip is completed so as not to interfere with the desired cabin temperature control.

[0111] It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the application.

Claims

1. A control system for controlling a vehicle heat pump system, the vehicle heat pump system being operable in a heating mode at a first pressure, wherein: The control system includes one or more controllers and is configured to: receiving a moisture signal indicative of moisture on a surface of a first heat exchanger of the vehicle heat pump system; determining a requirement for removing moisture based on the moisture signal; as well as A control signal is output for controlling the vehicle heat pump system to operate at a second pressure greater than the first pressure so that the surface of the first heat exchanger is heated to remove moisture from the surface.

2. The control system according to claim 1, wherein: The moisture signal indicates at least one of the following: temperature or humidity near the first heat exchanger; a usage history of the vehicle heat pump system, the usage history indicating that the vehicle heat pump system has previously been operated in a cooling mode; user input to remove moisture from the surface of the first heat exchanger; and Identification that a vehicle including the vehicle heat pump system has completed a trip.

3. The control system according to claim 1 or 2, wherein: The control system is configured to send an output instruction to a user requesting user confirmation based on the determination of the requirement for removing moisture, and Based on receiving the user confirmation, the control signal is output to control the vehicle heat pump system to operate at the second pressure.

4. A control system according to any preceding claim, wherein: The control system is configured to receive a signal indicating that the vehicle has completed a trip, and wherein the control system is configured to defer output of the control signal to control the vehicle heat pump system to operate at the second pressure until the signal indicating that the vehicle has completed a trip is received.

5. A control system according to any preceding claim, wherein: The second pressure is between 14 and 20 bar.

6. A vehicle heat pump system operable in a heating mode at a first pressure, the vehicle heat pump system comprising: a first heat exchanger; as well as A control system as claimed in any preceding claim.

7. The vehicle heat pump system according to claim 6, wherein: The control system is configured to output the control signal for controlling the vehicle heat pump system to operate in the heating mode at the second pressure such that the temperature of the surface of the first heat exchanger increases to at least 50°C, optionally at least 60°C.

8. The vehicle heat pump system according to any one of claims 6 or 7, comprising a control valve configured to control a flow direction of a fluid around the vehicle heat pump system so as to operate the vehicle heat pump system in the heating mode or in the cooling mode; in, The control valve includes a three-way valve configured to selectively connect the compressor and the first heat exchanger via a thermal expansion valve, and configured to selectively connect the compressor and the second heat exchanger; as well as The three-way valve is configured to selectively direct the fluid to bypass the second heat exchanger so that the hot fluid circulates through the compressor, the three-way valve, the thermal expansion valve and the first heat exchanger.

9. A vehicle heat pump system according to any one of claims 6 to 8, comprising a valve operable between open or restricted to selectively contain fluid in the first heat exchanger; in, The control system is configured to, in response to receiving the moisture signal, output a control signal to control the valve to be restricted so as to contain hot fluid in the first heat exchanger.

10. The vehicle heat pump system according to any one of claims 6 to 9, comprising at least one of a temperature sensor configured to detect a temperature near the first heat exchanger or a humidity sensor configured to detect a humidity near the first heat exchanger; in, The moisture signal includes at least one of a detected temperature or a detected humidity.

11. A vehicle comprising the control system according to any one of claims 1 to 5 or the vehicle heat pump system according to any one of claims 6 to 10.

12. A method for removing moisture from a surface of a first heat exchanger of a vehicle heat pump system, the vehicle heat pump system being operable in a heating mode at a first pressure, the method comprising: receiving a moisture signal indicative of moisture on a surface of the first heat exchanger; determining a requirement for removing moisture based on the moisture signal; as well as A control signal is output for controlling the vehicle heat pump system to operate at a second pressure greater than the first pressure so that the surface of the first heat exchanger is heated to remove moisture from the surface.

13. The method according to claim 12, wherein: The moisture signal indicates at least one of the following: a usage history of the vehicle heat pump system, the usage history indicating that the vehicle heat pump system has previously been operated in a cooling mode; user input to remove moisture from the surface of the first heat exchanger; and Identification that a vehicle including the vehicle heat pump system has completed a trip.

14. The method according to any one of claims 12 to 13, comprising: detecting a temperature near the first heat exchanger or a humidity near the first heat exchanger; as well as The moisture signal includes at least one of the detected temperature or the detected humidity.

15. Computer readable instructions which, when executed by a computer, are arranged to perform the method according to any one of claims 12 to 14.

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