Air conditioning device of a motor vehicle with a heat exchanger arrangement for heat absorption

Abstract

Air conditioning device (1) for conditioning the air of a passenger compartment (9) of a motor vehicle, which is designed for refrigeration operation and heat pump operation for cooling and heating the passenger compartment (9) as well as for post-heating operation, comprising - a heat exchanger arrangement for cooling air with a fan (5), an air guide and an evaporator (7), which is integrated in a refrigerant circuit, is designed to allow refrigerant flow and to be supplied with air in such a way that heat can be transferred from the air to the refrigerant, whereby the refrigerant is evaporated, wherein - the blower (5) is arranged in the direction of airflow in front of the evaporator (7) in such a way that waste heat from the blower (5) heats the air before it reaches the evaporator (7) and - the evaporator (7) is designed as a tube heat exchanger with tubes arranged in series, wherein the tube heat exchanger is designed with at least two rows, - a housing (2) with a first flow channel (3) and a second flow channel (4) for guiding air, which are separated from each other by a partition (10) and air guide devices (19, 20, 21, 22), wherein the refrigerant circuit comprises the evaporator (7), a compressor, a condenser (8) and an expansion element, wherein the evaporator (7) is arranged in the first flow channel (3) and the condenser (8) is arranged in the second flow channel (4), wherein - the condenser (8) is arranged in relation to the partition (10) in such a way that the first area is arranged within the first flow channel (3), covering a partial cross-section of the flow channel (3) and the second area is arranged within the second flow channel (4), covering the entire flow cross-section of the flow channel (4), wherein the heat transfer surface of the condenser (8) is arbitrarily divided in the areas, and - the air guide devices (19, 20, 21, 22) have coordinated shapes and form an air guide device for the condenser (8), wherein air guide devices (21) designed as air guide plates are arranged on the upstream side of the condenser (8) and air guide devices (22) designed as air guide plates are arranged on the downstream side of the condenser (8) and are each aligned parallel to the partition (10) such that ends repelling the condenser (8) each form a concave surface (23, 24) about an axis of rotation (25, 26) of the air guide devices (19, 20) designed as movable flaps, wherein the proportion of the areas of the condenser (8) in the first flow channel (3) and in the second flow channel (4) is adjustable by rotating the air guide devices (19, 20) about the respective axis of rotation (25, 26).

Description

[0001] The invention relates to an air conditioning device for conditioning the air in the passenger compartment of a motor vehicle, comprising a heat exchanger arrangement. The heat exchanger arrangement for cooling the air includes a fan, an air duct, and a heat exchanger. The heat exchanger is integrated into a refrigerant circuit, is designed to allow refrigerant flow, and is exposed to air such that heat can be transferred from the air to the refrigerant, causing the refrigerant to evaporate. The air conditioning device also includes a housing with a first and a second flow channel for guiding the air, as well as the refrigerant circuit with a first heat exchanger, which corresponds to the heat exchanger of the heat exchanger arrangement, a compressor, a second heat exchanger, and an expansion element. The first heat exchanger is located in the first flow channel, and the second heat exchanger is located in the second flow channel.

[0002] Furthermore, the invention relates to a method for operating the air conditioning device for a combined refrigeration and heating operation as well as for a post-heating operation to condition the air of the passenger compartment in the post-heating operation.

[0003] Modern automotive air conditioning systems, considered state-of-the-art, comprise refrigerant circuits with various components, such as the condenser (conventionally located at the front of the vehicle), the compressor (connected to and driven by the vehicle's engine), the evaporator (located in the passenger compartment), and hoses and connections. The air conditioning system conditions the air, which is then supplied to the passenger compartment. The compressor is typically driven by the vehicle's engine by coupling mechanical energy to the compressor shaft. The radiator fan and blower are electrically powered by the vehicle's 12V electrical system.

[0004] Air for the passenger compartment is drawn into the air conditioning unit by a fan and passed through the evaporator of the refrigerant circuit for cooling and / or dehumidification. When the air conditioning system is operating in refrigeration mode, heat is extracted from the vaporous refrigerant, compressed in the compressor, in the condenser at high pressure and released to the ambient air.

[0005] When installed in the front of the vehicle, the condenser is perpendicular to the airflow and typically has a large mesh area, which in small vehicles can reach values ​​in the range of 14 dm². 2 up to 18 dm 2 , for compact class vehicles, values ​​in the range of 20 dm 2 up to 22 dm 2 and for larger motor vehicles, values ​​above 24 dm 2 exhibits.

[0006] The mesh area is the surface at the inlet and outlet of the heat exchanger that is essentially perpendicular to the airflow direction and is also referred to as the flow surface. The mesh area encompasses the finned or ribbed section of the heat exchanger and corresponds to the air-side flow cross-section.

[0007] To draw ambient air through the heat exchangers, axial fans are used in radiators, positioned as suction fans at the air-side outlet of a so-called radiator module. Since axial fans move a large volume of air but generate a small pressure differential, the heat exchangers of the cooling module, arranged in series on the air-side and through which air flows—such as the coolant-to-air heat exchanger of the engine cooling circuit, the charge air cooler, and the condenser of the refrigerant circuit—are designed with the shallowest possible depth to reduce airflow resistance.

[0008] The depth refers to the thickness of the heat exchanger in the direction of airflow, or the air-side flow length.

[0009] In state of the art, in air conditioning systems for motor vehicles operating in heat pump mode and using ambient air as a heat source, the heat exchangers operated as condensers in refrigeration mode are used as evaporators.

[0010] During operation of the heat exchangers, which transfer heat from the refrigerant to the ambient air in refrigeration mode and absorb heat from the ambient air in heat pump mode, the ambient air is drawn through the heat exchanger by the radiator fan or a radiator fan assembly. Without additional air velocity based on the vehicle speed, i.e., when the vehicle is stationary, only low average airflow velocities of up to 3.5 m / s are achieved at maximum radiator fan speed.

[0011] However, the airflow velocity has a significant influence on the power that can be absorbed from the ambient air without icing of the heat exchanger, and thus on the heating output of a heat pump using ambient air as a heat source.

[0012] Furthermore, due to the arrangement of the cooling fan in the direction of airflow after the heat exchanger, which is known from the prior art, the waste heat generated in the drive of the cooling fan cannot be used.

[0013] Conventionally, the heat exchanger operating as an evaporator in refrigeration mode is supplied with an airflow of less than 600 kg / h. In contrast, the heat exchanger operating as a condenser in refrigeration mode and as an evaporator in heat pump mode is supplied with a significantly higher airflow of more than 1800 kg / h.

[0014] Air conditioning systems with heat pump functionality are also known from the prior art, in which the evaporator operates as an evaporator in both refrigeration and heat pump modes, and the condenser also operates as a condenser in both refrigeration and heat pump modes. The control of the heat flows is achieved entirely via the airflow direction.

[0015] FR 2 743 027 A1 describes a vehicle air conditioning system with a conventional refrigerant circuit, comprising only an evaporator, a compressor, a condenser, and an expansion element. The heat exchangers are arranged in separate flow channels, which are at least fluidically separated from one another. The flow channels have cross-connections or bypasses. The air mass flows, drawn in by fans, are directed over the surfaces of the heat exchangers as required and according to operating mode by opening and closing flaps and passing through the bypasses. In this process, the air mass flows are cooled and / or dehumidified or heated, and then discharged into the passenger compartment and / or the environment.

[0016] German patent application DE 10 2011 052 752 A1 describes a modular vehicle air conditioning system for heating and cooling air. The system comprises a housing with a fan and flaps for adjusting airflow paths, as well as a refrigerant circuit with a condenser, an evaporator, a compressor, an expansion element, and associated connecting lines. The housing incorporates an evaporator airflow path with an integrated evaporator and a condenser airflow path with an integrated condenser. Each airflow path can be supplied with fresh air from the environment, recirculated air from the passenger compartment, or a mixture of both. The two airflow paths are interconnected via controllable flaps such that heating or cooling of the passenger compartment is achieved solely by adjusting the airflow path.

[0017] EP 2 679 419 A1 discloses a vehicle air conditioning system comprising a housing with an inlet opening for introducing ambient air and exhaust air from the passenger compartment, and an outlet opening for releasing supply air into the passenger compartment. The housing contains a first heat exchanger for heating and a second heat exchanger for cooling or dehumidifying the air in a refrigerant circuit. The housing has an outlet opening for discharging air cooled in the second heat exchanger and an outlet opening for discharging air heated in the first heat exchanger, each to the surrounding environment.

[0018] DE 699 20 298 T2 discloses an air conditioning device for conditioning the air in the passenger compartment of a motor vehicle, comprising a housing, two heat exchangers, and two fans. A first fan is configured to deliver a first air mass flow through a first section of a heat exchanger, while a second fan is configured to deliver a second air mass flow through a second section of the heat exchanger. A pivotable air guide is arranged within the housing in the direction of airflow upstream of the heat exchanger to control the air mass flows and their distribution through the heat exchanger.

[0019] In DE 35 13 952 A1, an air conditioning system for coaches is described, comprising a ready-to-install housing unit with a fresh air intake duct, a recirculation air intake opening, a recirculation / fresh air flap, radial fans, a flap arranged in a fan partition wall, and a combined heat exchanger for heating and / or cooling with an integrated condensate collection tray.

[0020] US patent 2007 / 0290057A1 relates to a blower for air conditioning systems in schools and hotels, featuring a single, motor-driven damper blade for controlling the supply air mixture of exhaust air and outside air. The damper can be pivoted to a full outside air position, a full exhaust air position, and various intermediate mixed air positions. US patent 2011 / 0139420A1 describes a microchannel heat exchanger with parallel-flow aluminum flat tubes.

[0021] Prior art also reveals control strategies for preventing evaporator icing during operation in heat pump mode. These strategies limit the power consumption in the evaporator depending on the ambient temperature, for example, via the temperature level or the evaporation pressure of the refrigerant. DE 10 2011 051 285 A1 discloses a method and a device for icing prevention control for an evaporator of a heat pump in vehicle air conditioning systems. The passenger compartment is heated by means of a heat pump with an evaporator, which uses ambient air as a heat source for evaporating the liquid refrigerant. The surface temperature of the ambient air is controlled by the icing prevention control device, depending on the ambient air temperature upstream of the evaporator.For control purposes, the surface temperature of the evaporator is estimated or calculated using signals for the pressure and temperature of the refrigerant flowing in the refrigerant line, measured in a section of the refrigerant line between the evaporator outlet and the compressor inlet. The dew point of the ambient air in front of the vehicle is determined, and the flow velocity of the ambient air and the temperature level of the evaporator surface are adjusted by means of the opening cross-section of the expansion valve, the refrigerant mass flow rate in the refrigerant line, and the fan speed, as well as the compressor stroke or speed, depending on the compressor type. Additionally, a minimum superheat is set at the evaporator to prevent local icing.

[0022] DE 197 45 028 A1 discloses a method and a device for evaporator-freeze control of an air conditioning system with a refrigerant circuit, which includes an evaporator arranged in a housing and means for the controllable supply of refrigerant to the evaporator with variable quantity or temperature. DE 10 2009 052 409 A1 relates to a defrosting method or defrost detection for the evaporator of a heat pump system.

[0023] The object of the present invention is to provide an air conditioning device with heating functionality, particularly for use in motor vehicles, with an advanced heat exchanger arrangement for cooling air, wherein heat is effectively extracted from the air by means of a refrigerant flowing through the heat exchanger, and the waste heat from an air handling unit can be used as a heat source. The refrigerant circuit of the air conditioning device should be designed with a minimal number of components and thus be cost-effective and require little maintenance. Furthermore, the air conditioning device should be designed for combined refrigeration and heat pump operation as well as for post-heating operation for heating, cooling, and dehumidifying the air to be conditioned in the passenger compartment.The system should also be able to operate in environments with low-capacity heat sources, such as low-loss combustion engines or hybrid drives consisting of a combustion engine and an electric motor, or in the absence of heat sources from the drive, such as in electrically powered vehicles, while still meeting all requirements for a comfortable climate in the passenger compartment.

[0024] The invention further aims to provide a method for operating the air conditioning device, with which effective operation is possible, particularly in reheating mode.

[0025] The problem is solved by an air conditioning device according to the invention for conditioning the air in the passenger compartment of a motor vehicle, comprising a heat exchanger arrangement for cooling the air. The heat exchanger arrangement includes a fan, an air duct, and a heat exchanger designed as an evaporator and arranged in a refrigerant circuit. The heat exchanger is designed to allow refrigerant to flow through it on one side and to allow air to flow through it on the other, such that heat can be transferred from the air to the refrigerant. The refrigerant evaporates during heat absorption.

[0026] Airflow refers, for example, to a flow channel in the air conditioning system, in which the air is guided and conditioned from the inlet to the outlet.

[0027] The blower of the heat exchanger assembly is conceptually arranged in the direction of airflow upstream of the heat exchanger, which is designed as an evaporator, such that the waste heat from the blower warms the air before it reaches the heat exchanger. According to the invention, the heat exchanger is designed as a tube heat exchanger with tubes arranged in rows, wherein the tube heat exchanger is designed with at least two rows.

[0028] By transferring the waste heat from the blower to the air supplied to the heat exchanger, the air mass flow is advantageously heated by about 1 K to 5 K.

[0029] The air conditioning device comprises a housing with a first and a second airflow channel, separated from each other by a partition and air guides, as well as the refrigerant circuit with the first heat exchanger designed as an evaporator, a compressor, a second heat exchanger designed as a condenser, and an expansion element. The first heat exchanger, designed as an evaporator, is located in the first airflow channel, and the second heat exchanger, designed as a condenser, is located in the second airflow channel. The first heat exchanger, designed as an evaporator, corresponds to the heat exchanger of the heat exchanger arrangement according to the invention.

[0030] According to the invention, the air conditioning device is designed for combined refrigeration and heat pump operation for cooling and heating the passenger compartment, as well as for post-heating. The setting of the respective operating mode is achieved solely by controlling air guides arranged within the housing of the air conditioning device and not by regulating the refrigerant circuit. According to the invention, the first heat exchanger is designed and operable as an evaporator for cooling and / or dehumidifying an air mass flow, independent of the operating mode, such that the power required in each operating mode can be transferred from the air mass flow directed over the heat transfer surface to the refrigerant.

[0031] The first heat exchanger, designed as an evaporator, is subjected to the same refrigerant flow on both the refrigeration system and air sides, both during operation in refrigeration system mode and in heat pump mode.

[0032] The second heat exchanger, regardless of the operating mode, is preferably designed as a condenser or gas cooler and is used to heat a mass air flow.

[0033] The second heat exchanger, designed as a condenser, is divided into a first and a second section with respect to the partition wall, arranged such that the first section covers a partial cross-section of the first flow channel, and the second section covers the entire cross-section of the second flow channel. The heat transfer surface of the heat exchanger is variably divided between these sections.

[0034] The coordinated air guides form an air guide system for the condenser. These air guides, designed as air deflectors, are arranged on the upstream side of the condenser and aligned parallel to the partition wall such that the ends pointing away from the condenser form a concave surface around the axis of rotation of a movable flap-type air guide. The proportion of the condenser area within the first and second flow channels can be adjusted by rotating the air guide.

[0035] According to a further development of the invention, the heat exchanger designed as an evaporator has a flow area in the range of 2 dm². 2 up to 10 dm 2 , preferably in the range of 4 dm 2 up to 5 dm 2With this flow area, the heat exchanger can be used as an evaporator in both refrigeration system and heat pump operation of the air conditioning system of a motor vehicle to transfer the required power, and has a smaller flow area than heat exchangers known from the prior art, which are operated as condensers in refrigeration system mode of an air conditioning system and as evaporators in heat pump mode.

[0036] In a first alternative embodiment, all tube rows of the heat exchanger, which is designed as an evaporator, are traversed by a single flow. The tube rows are advantageously oriented perpendicular to the airflow direction. The refrigerant flows in one direction, parallel to all tubes of a tube row, before being directed through the tubes of the following tube row. In this way, the refrigerant flows through the tubes of different tube rows sequentially, i.e., in series. In a second alternative embodiment, the heat exchanger, which is designed as an evaporator, is configured such that at least one of the multiple tube rows is traversed by multiple flows. In this configuration, the refrigerant flows through some tubes of a tube row in a first direction, while through other tubes of the same tube row it flows in a second direction, opposite to the first.The refrigerant flows parallel through the pipes of the pipe series.

[0037] The flow of refrigerant from one row of pipes to the next can take place either in or against the air-side flow direction, so that the heat exchanger is designed either as a cross-coordinate flow heat exchanger or as a cross-counterflow heat exchanger.

[0038] The heat exchanger, designed as an evaporator, is advantageously constructed from flat tubes oriented perpendicular to the airflow direction, with their flat sides facing the airflow direction. The flat tubes have a width greater than 8 mm. A width of 11.5 mm to 18 mm is preferred. A width of 12.3 mm or 16 mm is particularly advantageous.

[0039] The width of the flat tubes refers to the extent of the tubes in the direction of airflow.

[0040] The heat exchanger, designed as an evaporator, is preferably equipped with fins on the air side. The fins are advantageously arranged at a density of less than 100 fins per dm³, preferably at a density of 70 to 80 fins per dm³.

[0041] The heat exchanger arrangement can be advantageously used - in heat pump mode - an air mass flow with an air velocity of more than 3.5 m / s, preferably about 5 m / s, is conveyed to the evaporator - an air mass flow of over 600 kg / h, preferably of about 1,000 kg / h, is conveyed to the evaporator, which, for example, with an air inlet temperature to the evaporator of less than +10°C, preferably less than 0°C, and a power output of over 1 kW, is only slightly cooled by less than 10 K, preferably less than 5 K, - a power output in the range of 0.3 kW to 6 kW can be transmitted, wherein, for example, at an ambient temperature of -10°C a power output in the range of 0.5 kW to 6 kW, preferably in the range of 2 kW to 3 kW, is transmittable, as well as - in refrigeration system mode - an air mass flow of less than 600 kg / h, preferably of about 400 kg / h, is conveyed to the evaporator, whereby a power of more than 2 kW can be transmitted, and - a power of more than 0.5 kW can be transmitted, whereby, for example, at ambient temperatures above +30°C a power in the range of 4 kW to 8 kW, preferably about 6 kW, can be transmitted.

[0042] The air conditioning unit with heat pump functionality, i.e., with the cooling and / or dehumidification of a first air mass flow and the simultaneous heating of a second air mass flow, can advantageously be operated in a reheat mode. The reheat mode can be operated as a pure reheat mode, i.e., without the mixing of unconditioned air.

[0043] The processes of cooling and / or dehumidifying the air, as well as heating or reheating the air, are controlled solely on the air side. The refrigerant circuit operates independently of the different operating modes and does not switch between them. Heat flow control is achieved entirely via the air-side flow direction. Switching the operation of a heat exchanger between condenser and evaporator is unnecessary. Only parameters such as the opening cross-section of the expansion valve and / or the compressor speed are regulated based on external conditions like ambient temperature or air mass flow.

[0044] The inventive method for operating the air conditioning device for a combined refrigeration system and heat pump operation for cooling and heating, as well as for a post-heating operation for conditioning the air of a passenger compartment of a motor vehicle, comprises the following steps in the post-heating operation: - Conveying a first partial air mass flow and a second partial air mass flow in the air conditioning device, - Cooling of the first partial air mass flow as it passes over the evaporator and - Splitting the cooled first partial air mass flow into a partial air mass flow that is discharged into the environment, a partial air mass flow for reheating, and a cold air mass flow. - Heating the second partial air mass flow and the partial air mass flow for reheating when flowing over the heat transfer surface of the condenser, - Mixing the reheated partial air mass flow with the preconditioned cold air mass flow, whereby - the cooling capacity used is regulated via the temperature of the first partial air mass flow after the evaporator and the pressure level of the refrigerant in the evaporator, - the temperature of the mixed air mass flow is detected via at least one temperature sensor arranged in the air mass flow and is regulated by adjusting the ratio of the partial air mass flow for reheating and the preconditioned cold air mass flow by positioning air guide devices, and - Introducing the mixed air mass flow into the passenger compartment.

[0045] To determine the temperatures, temperature sensors are preferably arranged both within the cooled first partial air mass flow and within the mixed air mass flow.

[0046] The cooling capacity is regulated by means of an air guidance device to direct the first partial air mass flow over the evaporator and thus the pressure level of the refrigerant in the evaporator.

[0047] According to one alternative, the first and second partial air mass flow are introduced into the air conditioning device as a common air mass flow and divided within the air conditioning device.

[0048] In a second alternative, the first and second partial air mass flows are introduced into the air conditioning system as separate partial air mass flows. These partial air mass flows can have different temperatures and / or absolute humidity levels.

[0049] The division of the cooled first partial air mass flow into the partial air mass flow to be discharged into the environment, the partial air mass flow for reheating, and the cold air mass flow is carried out according to the requirements for the air mass flow to be conveyed into the passenger compartment with regard to air volume, temperature, and humidity.

[0050] According to a further development of the invention, the ratio of the partial air mass flow for reheating and the preconditioned cold air mass flow is regulated between 0% and 100%. The proportion of the cooled first partial air mass flow that is not discharged to the environment can be divided into fractions from 0% to 100%. With fractions of 0% or 100%, the entire partial air mass flow is directed either as a partial air mass flow for reheating or as a cold air mass flow. With a fraction other than 0% or 100%, a portion is directed both as a partial air mass flow for reheating and as a cold air mass flow.

[0051] An advantage is that the first and second partial air mass flow are not mixed, or only to a negligible extent, when flowing over the heat transfer surfaces of the condenser.

[0052] The heating capacity for reheating is advantageously controlled by dividing the condenser's heat transfer surface into a first and a second area, by directing the second partial air mass flow through the second area of ​​the condenser, and by adjusting the ratio of the partial air mass flow for reheating to the preconditioned cold air mass flow by positioning air guides. The heating capacity is therefore also controlled by the refrigerant pressure level in the condenser.

[0053] A method for detecting and preventing icing of an evaporator in an air conditioning system comprises the following steps: - Measuring the power consumption of a blower associated with the evaporator, - Determining the electrical power consumption of the blower for conveying air through the evaporator, - Comparing the electrical power consumption of the blower with a target value, whereby the target value is determined as a reference value from a characteristic curve of the blower, - Initiating measures to prevent icing or initiating active de-icing if the target value is undershot.

[0054] The electrical power consumption of the blower depends primarily on the volume of air moved and only secondarily on the air-side flow resistance of the heat exchanger assembly. Due to the increasing flow resistance as the heat transfer surface begins to ice up, the same volume of air can no longer be moved with an unchanged blower. The air volume, and therefore the electrical power consumption, decreases. The blower's characteristic curve shows the achievable air flow rate as a function of flow resistance. By measuring the current consumption of the blower associated with the evaporator, the onset of icing can be detected, allowing for the implementation of measures to prevent icing or active defrosting.

[0055] In summary, the solution according to the invention has several advantages: - Effectively operable air conditioning device for simultaneous dehumidification and heating, - Rapid provision of warm air at low ambient temperatures and cold engine coolant in motor vehicles with internal combustion engines, - minimal complexity in the refrigerant circuit, which essentially means eliminating the need for switching valves and minimizing the number of expansion valves, heat exchangers and refrigerant lines, as well as - Reduction of the power required to heat the passenger compartment through recirculation operation and / or targeted airflow within the flow channels.

[0056] Further details, features, and advantages of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. These show an air conditioning device with a centrally arranged condenser and four flaps: Fig. 1: with two blowers, Fig. 2a: with a blower, Fig. 2b: Air conditioning device according to Fig. 2a in refrigeration system mode, Fig. 2c: Air conditioning device according to Fig. 2a in post-heating mode with dehumidification, Fig. 2d: Air conditioning device according to Fig. 2a in heat pump mode and Fig. 2e: Air conditioning device according to Fig. 2a in mixed operation.

[0057] Fig. Figure 1 shows an air conditioning device 1 with a centrally arranged heat exchanger designed as a condenser 8 and a housing 2, comprising a first flow channel 3 and a second flow channel 4, wherein each flow channel 3, 4 is assigned a fan 5, 6 and can be supplied with fresh air from the environment, recirculated air from the passenger compartment 9, or a mixture of both. The central arrangement refers to the orientation of the condenser 8 with respect to a partition 10, which divides the condenser 8 into two equal sections. The second section is arranged within the second flow channel 4 and covers the entire flow cross-section of the flow channel 4. The first section of the condenser 8 is arranged within the first flow channel 3 and covers only a partial cross-section of the flow channel 3.

[0058] While only the condenser 8 is located in the second flow channel 4, a heat exchanger designed as an evaporator 7 is also located in the first flow channel 3. Both are components of a refrigerant circuit of the air conditioning device 1 and are designed as air-cooled heat exchangers. The evaporator 7 occupies the entire flow cross-section of the flow channel 3. The condenser 8 is arranged across the flow channels and has two sections. The second section is located within the second flow channel 4, covering the entire flow cross-section, and extends into the first flow channel 3, so that the first section of the condenser 8 is located within the first flow channel 3.

[0059] The first and second flow channels 3, 4 are separated from each other by the partition 10, as well as by two additional air guide devices 19, 20 designed as movable flaps and by static air guide devices 21, 22 designed as air deflectors. The air mass flow directed through the condenser 8 is determined according to the speed of the blower 6 and the position of the air guide devices 19, 20.

[0060] The cross-channel arrangement of the condenser 8 results in a controllable division of the heat transfer surface into two areas. The condenser 8 can be subdivided into areas ranging from 0% to 100% of the total heat transfer surface. With subdivisions of 0% or 100%, the condenser 8 is located entirely within one of the flow channels 3 or 4. In a heat exchanger arrangement with a heat transfer surface division other than 0% or 100%, the areas are located proportionally within flow channel 3 and within flow channel 4. For example, in a heat exchanger arrangement with a 30% division of the heat transfer surface, 30% of the area is located within flow channel 3 and 70% within flow channel 4.

[0061] According to an alternative embodiment (not shown), the cross-channel arrangement of the condenser 8 results in a non-adjustable division of the heat transfer surface into two areas. The condenser 8 is further subdivided into areas ranging from 0% to 100%, but preferably from 0% to 30%, of the total heat transfer surface.

[0062] The separately controllable fans 5, 6 result in advantageous dynamics of the air conditioning device 1, since the first flow channel 3 with the evaporator 7 and the second flow channel 4 with the condenser 8 can be supplied with air mass flows of different velocities and thus enable a rapid response to changing operating conditions.

[0063] The blower 5 of the first flow channel 3 directs the intake air as an air mass flow to the evaporator 7. As the air mass flow passes over the heat transfer surfaces of the evaporator 7, it is cooled and / or dehumidified.

[0064] The cooled and / or dehumidified partial air mass flow exiting the evaporator 7 can be divided in a required ratio via the cold air flow path 11 into the environment and via the cold air flow path 12 into the passenger compartment 9, or it can be completely assigned to one of the cold air flow paths 11 or 12. The partial air mass flow is divided by means of the air guide device 13, which is designed as a flap.

[0065] The partial air mass flow through the cold air flow path 12 can be further divided into a cold air mass flow and a partial air mass flow for reheating. The cold air mass flow passing through the cold air flow path 12 is routed around the condenser 8 via the bypass channel 14. The partial air mass flow for reheating is routed through the first part of the condenser 8 and heated to the temperature specified by the climate control system.

[0066] Similar to blower 5, blower 6 draws in air and directs the drawn-in air as an air mass flow to condenser 8. As the air mass flow passes over the heat transfer surfaces of condenser 8, it is heated.

[0067] The warm air mass flow exiting the condenser 8 can be divided into a partial air mass flow via warm air flow path 15 to the environment and a partial air mass flow via warm air flow path 16 to the passenger compartment 9 in a required ratio, or it can be completely assigned to one of the warm air flow paths 15 or 16. The warm air mass flow is divided by means of the air guide device 17, which is designed as a flap.

[0068] Alternatively, the air guide devices 13, 17, designed as flaps, can each be configured as two separate flaps, with two flaps arranged within the cold air flow paths 11, 12 and two flaps within the warm air flow paths 15, 16. The two flaps can each be coupled by a kinematic device and adjustable by means of a single actuator.

[0069] The coordinated air guide devices 19, 20 and the air guide devices 21, 22 designed as air guide plates form an air guide device for the heat exchanger and serve to prevent the mixing of the cooled and conditioned air mass flow within the first flow channel 3 with the unconditioned air mass flow of the second flow channel 4 when flowing through the evaporator 7.

[0070] The air guide devices 21, 22, designed as air guide plates, are arranged parallel to the partition wall 10, so that the air mass flows flowing along the partition wall 10 do not experience any deflection in the flow direction when flowing towards the air guide devices 21, 22 designed as air guide plates and when flowing past or through them.

[0071] The air guide devices 21, 22, designed as air deflectors and arranged on both sides into the flow channels 3, 4 and thus further away from the partition 10, have an increasing length L. The further the air guide devices 21, 22, designed as air deflectors, are arranged from the partition 10, the greater the length L of the air guide devices 21, 22, whereby the lengths L of the air guide devices 21, 22 arranged side by side increase in such a way that the ends of the entire arrangement of the air guide devices 21, 22, designed as air deflectors, form two concave surfaces 23, 24.Surfaces 23, 24 are each rectangular and uniformly curved about an axis parallel to them, such that the first two opposite edges of each rectangular surface 23, 24 form a straight line, while the second two opposite edges describe a circular arc. The centers of these arcs represent the axis around which the rectangular surface 23, 24 is curved. These axes correspond to the axes of rotation 25, 26 of the movable air guides 19, 20. The radii of the circularly curved surfaces 23, 24 correspond to the longitudinal extent of the air guides 19, 20, that is, the extent of the movable air guides 19, 20 in the direction of airflow through the flow channels 3, 4.

[0072] The pivotable air guides 19, 20 are aligned with their side edge facing away from the axis of rotation 25, 26 towards the concavely curved surface 23, 24 spanned by the ends of the air guides 21, 22, which are designed as air guide plates. To allow free movement of the air guides 19, 20, a minimal gap remains between the surface 23, 24 and the side edge of the air guide 19, 20, which does not affect the air mass flow or only to a negligible extent. By simultaneously rotating the air guides 19, 20 about their respective axes of rotation 25, 26 in opposite directions 27, 28, the proportion of the condenser 8 sections in the first flow channel 3 and in the second flow channel 4 can be adjusted. The division of the condenser 8 sections can be essentially stepless.Possible stages within the rotation of the air guide devices 19, 20 result from the spacing of the air guide devices 21, 22, designed as air guide plates, perpendicular to the direction of airflow through the flow channels 3, 4. After rotation, the air guide devices 19, 20 are aligned such that the side edges arranged parallel to and facing away from the axis of rotation 25, 26 are opposite an end of an air guide device 21, 22 designed as an air guide plate, so that the air flow can flow along a continuous flow surface. The leakage flows occurring at intermediate positions of the air guide devices 19, 20 with respect to the air guide devices 21, 22 designed as air guide plates are negligible.An intermediate position is understood to be a position of the air guide devices 19, 20 in which the side edges of the air guide devices 19, 20 are not exactly opposite an edge of an air guide device 21, 22 designed as an air guide plate, but are arranged between two air guide plates.

[0073] When the air guide devices 19, 20 are rotated in the directions 27, 28 until they reach their maximum longitudinal extent, i.e., until they reach the outer housing wall of the second flow channel 4, the entire condenser 8 is located within the first flow channel 3. The air guide devices 19, 20 are in their first end position. When the air guide devices 19, 20 are rotated opposite to the directions 27, 28 until they reach their maximum longitudinal extent, i.e., towards the outer housing wall of the first flow channel 3 or towards the bypass channel 14, the entire condenser 8 is located within the second flow channel 4. The air guide devices 19, 20 are in their second end position.In addition to the two end positions, the air guide devices 19, 20 can be adjusted to intermediate positions. The middle intermediate position is shown in . Fig. 1 shown.

[0074] When operating in refrigeration or heat pump mode, the air guide devices 19, 20 are arranged in the second end position. The condenser 8, with its heat transfer surface, is completely located within the second flow channel 4.

[0075] During operation in refrigeration mode, the air guide 13 opens the bypass channel 14 and closes the cold air flow path 11 to the environment, so that the air mass flow drawn in by the blower 5, conveyed through the first flow channel 3 to the evaporator 7, and cooled and dehumidified as it flows over the evaporator 7, is directed through the bypass channel 14 and the cold air flow path 12 into the passenger compartment 9. Conversely, the air mass flow conveyed by the blower 6 in the second flow channel 4 to the condenser 8, and heated as it flows over the condenser 8, is discharged into the environment through the warm air flow path 15, which is opened by the air guide 17. The warm air flow path 16 is closed. The air guides 19 and 20 are oriented such that the condenser 8 is located entirely within the second flow channel 4.

[0076] When operating in heat pump mode, i.e., when heating the air supplied to the passenger compartment 9, the air guide 13 opens the cold air flow path 11 and closes the bypass channel 14. This allows the air mass flow drawn in by the blower 5, conveyed through the first flow channel 3 to the evaporator 7, and cooled as it passes over the evaporator 7, to be discharged into the environment via the cold air flow path 11. Conversely, the air mass flow drawn in by the blower 6, conveyed through the second flow channel 4 to the condenser 8, and heated as it passes over the condenser 8, is conveyed into the passenger compartment 9 via the warm air flow path 16, which is now opened by the air guide 17, while the warm air flow path 15 remains closed. The air guidance devices 19, 20 are aligned such that the condenser 8 is completely arranged in the second flow channel 4.

[0077] The blowers 5 and 6 are arranged in the direction of airflow through the flow channels 3 and 4, respectively, upstream of the evaporator 7 and the condenser 8. The heat generated by the blowers 5 and 6 is transferred to the air, warming the airflows by approximately 1 K to 5 K. In this warmed state, the air is then directed to the evaporator 7 and the condenser 8. Thus, the heat generated by the blowers 5 and 6 can be used to warm the air supplied to the passenger compartment.

[0078] During operation in post-heating mode, the air guide devices 13, 17 are arranged in various positions between fully open and fully closed, as required, and the air guide devices 19, 20 are arranged between their end positions. The position of the air guide device 13 and the speed of the blower 5 vary the preconditioned air mass flow to be heated.

[0079] The heat exchanger designed as evaporator 7 is always used, regardless of the operating mode, i.e., both in refrigeration mode and in heat pump mode, to absorb heat from the refrigerant while simultaneously cooling and / or dehumidifying the air mass flow.

[0080] The heat exchanger, designed as condenser 8, is always used to transfer heat from the refrigerant to the air mass flow, regardless of the operating mode.

[0081] The embodiment according to the Fig. 2a to 2e demonstrates, in comparison to the air conditioning device 1, that Fig. 1 only a blower 29, which conveys the air mass flow through both the first flow channel 3 and the air mass flow through the second flow channel 4. This air conditioning device 1 essentially comprises three air guide elements designed as air guide devices 13, 19, 20, which are sufficient for control. The air guide device 20 takes over the function of the air guide device 17 from Fig. 1, that is, the closing and opening of the warm air flow paths 15, 16. The fourth air guide device 18, designed as a flap, serves to close and open the bypass channel 14. The ratio of the air mass flows via the evaporator 7 and the condenser 8 can also be adjusted with the air guide device 18.

[0082] When operating in refrigeration mode after Fig. 2b, the air guide devices 19, 20 are arranged in the second end position, such that the condenser 8 is completely located within the second flow channel 4. The air guide device 13 opens the cold air flow path 12 and closes the cold air flow path 11 to the environment. The air mass flow, cooled and dehumidified as it flows over the evaporator 7, is directed into the passenger compartment 9 via the cold air flow path 12. The air mass flow, heated as it flows over the condenser 8, is directed to the environment via the warm air flow path 15, which is opened by the air guide device 20. The warm air flow path 16 is closed.

[0083] When operating in heat pump mode with unconditioned air after Fig. 2d The air guide 13 opens the cold air flow path 11 and closes the cold air flow path 12 to the passenger compartment 9, so that the air mass flow cooled as it passes over the evaporator 7 is discharged into the environment via the cold air flow path 11. Conversely, the air mass flow heated as it passes over the condenser 8 is conveyed into the passenger compartment 9 via the warm air flow path 16, which is now opened by the air guide 20, while the warm air flow path 15 remains closed.

[0084] The air guide devices 19 and 20 are arranged in opposite directions to each other. Air guide device 19 is in the first end position, while air guide device 20 is in the second end position, simultaneously closing the warm air flow path 15 and opening the warm air flow path 16.

[0085] Operation in pure heat pump mode or heating mode with unconditioned air is activated when dehumidification of the air supplied to the passenger compartment 9 is neither necessary nor desired. The blower 29 is positioned upstream of the evaporator 7 and the condenser 8 in the direction of airflow, so that the air mass flow is warmed by approximately 1 K to 5 K through the heat transfer of the blower 29's waste heat to the air and is then directed to the evaporator 7 and the condenser 8 in its warmed state. Thus, the waste heat from the blower 29 can be used to warm the air supplied to the passenger compartment.

[0086] When heating is necessary during full heating operation and simultaneous dehumidification of the air supplied to the passenger compartment 9, the second flow channel 4 is closed by means of the air guide device 19, which, like the air guide device 20, is in the second end position, which Fig. As can be seen in 2c. The entire air mass flow delivered by the blower 29 is directed through the evaporator 7. The air guide device 18 would close the bypass channel 14.

[0087] Since the heat output at the condenser 8 in a closed refrigerant circuit comprising an evaporator 7, a compressor, and a condenser 8 is the sum of the power supplied to the refrigerant at the evaporator 7 and in the compressor, and thus the heat output at the condenser 8 is only greater than the power supplied to the evaporator 7 by the power supplied to the compressor, the air can only be heated slightly when flowing over the heat transfer surfaces of the condenser 8. With the same air mass flow rate, only the compressor power and the power gained from dehumidifying the air can be supplied, taking into account the system losses.

[0088] To achieve a greater heating output at the condenser 8 and to heat the air mass flow supplied to the passenger compartment 9 more effectively, a first portion of the air mass flow, which has passed over the evaporator 7 and been cooled and dehumidified in the process, is discharged into the environment, while the second portion of the air mass flow is routed over the condenser 8, heated in the process, and then supplied to the passenger compartment 9. The air mass flow is divided by means of the control of the air guide device 18 located in the bypass channel 14.

[0089] Since the air mass flow supplied to passenger compartment 9 is reduced by the portion discharged into the environment, a greater heating of the air mass flow supplied to passenger compartment 9 is possible.

[0090] How Fig.Figure 2e shows that the air conditioning device 1 can be operated in mixed mode in addition to operation in refrigeration mode and pure heating mode. In this mixed mode, the conditioned air consists of a proportion of cooled and dehumidified air as well as a proportion of cooled, dehumidified and reheated air.

[0091] The blower 29 conveys an air mass flow through the first flow channel 3, which flows completely over the evaporator 7, is cooled and dehumidified in the process, as well as an air mass flow through the second flow channel 4, which is directed over a part of the condenser 8 and removes the heat absorbed in the evaporator 7.

[0092] The air guide devices 19, 20 are arranged such that a second section of the condenser 8 is located in the second flow channel 4 and a first section of the condenser 8 is located in the first flow channel 3. The air mass flow conveyed through the second flow channel 4 is discharged into the environment via the warm air flow path 15, which is released by the air guide device 20.

[0093] A first portion of the air mass flow, conditioned as it passes over the evaporator 7, is directed through the bypass channel 14 to the cold air flow path 12 by opening the air guide 18. This portion of the air mass flow is not further conditioned. A second portion of the partial air mass flow, which passes over the evaporator 7, is directed parallel to the partial air mass flow in the flow channel 4, over the first section of the condenser 8, to the warm air flow path 16, and is heated in the process. The partial air mass flow from the cold air flow path 12, which passes through the bypass channel 14 and is not further conditioned (i.e., only cooled and dehumidified), is mixed with the additional partial air mass flow from the warm air flow path 16, which is also directed over the condenser 8 and thus heated, and is then introduced into the passenger compartment 9. LIST OF REFERENCE MARKS 1 air conditioning unit 2 cases 3 first flow channel 4 5, second flow channel 6 blowers 7 evaporators 8 Capacitor 9 Passenger compartment 10 Partition wall 11, 12 Cold air flow path 13 Air guidance system for the cold air flow paths 11, 12 14 Bypass channel in the first flow channel 3 15, 16 Warm air flow path 17 Air guidance device for the warm air flow paths 15, 16 18 Air guidance device of the bypass duct 14 19, 20 Air guidance system 21, 22 static air guidance system 23, 24 area 25, 26 Axis of rotation of the air guidance device 19, 20 27, 28 Direction of rotation of the air guide device 19, 20 29 blowers Length L

Claims

Air conditioning device (1) for conditioning the air of a passenger compartment (9) of a motor vehicle, which is designed for refrigeration operation and heat pump operation for cooling and heating the passenger compartment (9) as well as for post-heating operation, comprising: - a heat exchanger arrangement for cooling air with a fan (5), an air guide and an evaporator (7), which is integrated in a refrigerant circuit, is designed to allow refrigerant flow and to be supplied with air in such a way that heat can be transferred from the air to the refrigerant, whereby the refrigerant is evaporated, wherein: - the fan (5) is arranged in the direction of airflow upstream of the evaporator (7) in such a way that waste heat from the fan (5) heats the air before it reaches the evaporator (7), and: - the evaporator (7) is designed as a tube heat exchanger with tubes arranged in series, wherein the tube heat exchanger is designed with at least two rows.- a housing (2) with a first flow channel (3) and a second flow channel (4) for guiding air, which are separated from each other by a partition (10) and air guide devices (19, 20, 21, 22), wherein the refrigerant circuit comprises the evaporator (7), a compressor, a condenser (8) and an expansion element, wherein the evaporator (7) is arranged in the first flow channel (3) and the condenser (8) in the second flow channel (4), wherein the condenser (8) is subdivided into a first region and a second region with respect to the partition (10) such that the first region is arranged within the first flow channel (3), covering a partial cross-section of the flow channel (3) and the second region is arranged within the second flow channel (4), wherein the heat transfer surface of the condenser (8) is arbitrarily divided in the regions,and- the air guide devices (19, 20, 21, 22) have shapes coordinated with each other and form an air guide device for the condenser (8), wherein air guide devices (21) designed as air guide plates are arranged on the upstream side of the condenser (8) and air guide devices (22) designed as air guide plates are arranged on the downstream side of the condenser (8) and are each aligned parallel to the partition (10) such that ends repelling the condenser (8) each form a surface (23, 24) shaped concavely about an axis of rotation (25, 26) of the air guide devices (19, 20) designed as movable flaps, wherein the proportion of the areas of the condenser (8) in the first flow channel (3) and in the second flow channel (4) is adjustable by rotating the air guide devices (19, 20) about the respective axis of rotation (25, 26). Air conditioning device (1) according to claim 1 , characterized in that the evaporator (7) has a flow area in the range of 2 dm2 to 10 dm2. Air conditioning device (1) according to claim 1 , characterized in that the evaporator (7) is configured such that the rows are subjected to single-flow circulation. Air conditioning device (1) according to claim 1, characterized in that the evaporator (7) is configured such that at least one row is multi-flowed. Method for operating an air conditioning device (1) according to any one of claims 1 to 4 for combined refrigeration and heat pump operation for cooling and heating, as well as for post-heating operation for conditioning the air of the passenger compartment (9) of a motor vehicle, comprising the following steps in post-heating operation: - conveying a first partial air mass flow and a second partial air mass flow in the air conditioning device (1), - cooling the first partial air mass flow as it flows over the evaporator (7), and - splitting the cooled first partial air mass flow into a partial air mass flow that is discharged to the environment, a partial air mass flow for post-heating, and a cold air mass flow, - heating the second partial air mass flow and the partial air mass flow for post-heating as it flows over the heat transfer surface of the condenser (8), - mixing the post-heated partial air mass flow with the pre-conditioned cold air mass flow.wherein- the cooling capacity used is controlled via the temperature of the first partial air mass flow after the evaporator (7) and the pressure level of the refrigerant in the evaporator (7),- the temperature of the mixed air mass flow is detected via at least one temperature sensor arranged in the air mass flow and is controlled via the ratio of the partial air mass flow for reheating and the preconditioned cold air mass flow by positioning air guide devices (13, 18, 19, 20), and- introduction of the mixed air mass flow into the passenger compartment (9). Method according to claim 5, characterized in that the ratio of the partial air mass flow for reheating and the preconditioned cold air mass flow is regulated between 0% and 100%. Method according to claim 5 or 6, characterized in that the heating power for reheating is controlled by a controllable division of the heat transfer surface of the condenser (8) into the first and second areas and the second partial air mass flow directed through the second area of ​​the condenser (8), as well as the ratio of the partial air mass flow for reheating and the preconditioned cold air mass flow by positioning the air guide devices (13, 18, 19, 20).

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