WO2019241813A1

WO2019241813A1 - Method for cooling a vehicle cabin

Info

Publication number: WO2019241813A1
Application number: PCT/AT2019/060199
Authority: WO
Inventors: Friedrich Vogel; Rudolf Faworka
Original assignee: Enio Gmbh
Priority date: 2018-06-17
Filing date: 2019-06-17
Publication date: 2019-12-26
Also published as: AT521450B1; AT521450A1

Abstract

The invention relates to a method for cooling a vehicle cabin (3) of a vehicle (1). The aim of the invention is therefore to provide a vehicle and a method for cooling for a vehicle of the aforementioned type, the cooling of which is fuel-saving and nevertheless efficient. This aim is achieved in that a primary fresh air stream (6b) is pre-cooled and the primary fresh air stream (6b) thus pre-cooled is further cooled by supplying water, and a primary heat exchange of the cooled primary fresh air stream (6b) with an internal air stream (8b) from the internal air of the vehicle cabin (3) is carried out.

Description

Method for cooling a vehicle cabin

The invention relates to a method for cooling a vehicle cabin of a vehicle and a vehicle with a cooling device for cooling a vehicle cabin.

The additional consumption of fuel for the operation of air conditioning systems in vehicles with fossil fuels in Austria is around 380 million liters / year, the resulting pollutant emissions 0.9 million tons of C0 ₂ , or 8% of the total pollutant emissions of vehicles. The commercial value of this additional consumption is around 400 million euros. In addition to the costs and environmental disadvantages of known vehicle air conditioning systems, there is also a health disadvantage. In particular at high outside temperatures, the cooling air must be blown into the passenger compartment at a high flow rate in order to achieve a sufficient temperature reduction in the interior. The resulting drafts can not only cause a slight feeling of comfort, but also colds, muscle tension, headaches and body aches. This results in economically relevant costs for sick leave and days of treatment. Air conditioning of vehicles is another problem for electric vehicles. With a storage capacity of economically and environmentally politically justifiable vehicle batteries of currently around 30 kWh, the energy consumption of the air conditioning system reduces the short range of most vehicles from around 150 km - 200 km by almost 15%.

Studies have shown that depending on the type and exterior color of the vehicle, the additional fuel required by air conditioning systems in motor vehicles already has an outside temperature of 28 ° C and a passenger compartment target temperature of 22 ° C in urban traffic between 0.7 and 2.1 liters each Is 100 km. (Source: ADAC Germany). These values were measured by the German Car Driver Club based on the European exhaust type test (NEDC = New European Driving Cycle) by comparing trips with and without air conditioning. Since the energy requirement of car air conditioning systems is time and not route-dependent, this is even higher at low average speeds. With an energy density of fossil fuels of around 9 kWh per liter of petrol or diesel, this means a demand from 6.3 to around 19 kWh / 100 km. If one calculates with average values for the additional consumption of 1.4 liters / 100 km or the average mileage of European vehicles of 15,000 km / year, this means under the assumption that Europe requires air conditioning for around 40% of the journey time, an annual additional requirement of 84 liters of fossil fuel and thus around 8% of the total annual requirement of 1050 liters on average. The additional output of C02 per vehicle with air conditioning is around 20% in cooling mode and therefore a total of around 200 kg C0 ₂ per year. For a vehicle fleet of 4.5 million vehicles, such as those used in Austria in 2008, this means - in total - a pollutant emission of 0.9 million tons of C0 ₂ caused by the vehicle air conditioning systems. or 8% of the total pollutant emissions from vehicles with fossil fuels (only cars). The additional consumption by vehicle air conditioning systems of 8% over the entire year means an additional consumption of 378 million liters of fuel for Austria and thus a commercial value (for 2009) of around 400 million euros. At a European level, a study by the French agency for the environment and energy ADEME comes to an even higher result. ADEME found that a car requires up to 35% more fuel to run an air conditioner. According to ADEME calculations, the greenhouse effect caused by the air conditioning of the approx. 16 million vehicles sold in Europe each year corresponds to the emissions of all cars registered in France in 2002.

Vehicles with automatic start-stop to save energy cannot utilize their energy-saving potential under hot ambient conditions, since the engine cannot be switched off to support the air conditioning system. Alternatively, the use of electrical air conditioning systems can be considered to enable a shutdown. However, these currently have a poor overall efficiency, since the electrical energy in turn is produced by the motor and has to be produced via a detour via an assembly.

The strong increase in the share of electric vehicles expected for the coming years represents another problem for air conditioning. The energy efficiency in the drive area for electric vehicles is 3 to 4 times that of vehicles with fossil fuels. A vehicle with an electric drive can cover a distance of around 5 km with a kWh, but a vehicle with fossil fuel can only travel 1 km to 2 km due to the poor efficiency of internal combustion engines.

The current vehicle air conditioning systems work according to the following principle: The air to be cooled is directed past an evaporator, in which the coolant, mostly a readily evaporating, environmentally problematic liquid, evaporates. The evaporation process cools the air flowing past significantly. The coolant is then passed into a circuit in gaseous form by being sucked in by a compressor and then cooled again and returned to its liquid state. Before the coolant gets back into the evaporator, moisture is removed from it in a dryer. For The entire process requires drive energy from the vehicle engine, either directly via a mechanical connection or indirectly via electrical energy, which in turn is generated by a generator. The energy required for this increases the fuel consumption of a vehicle during cooling by 0.4-1.2 1/100 km when driving on the motorway and 2.0-4.5-1 / 100 km in city traffic.

While indirect adiabatic cooling is already being used increasingly in air conditioning technology for buildings, adiabatic cooling for vehicles is currently known almost exclusively in direct form via heat exchangers. The VehiCool company in the USA (AURORA, CO) has been producing a system for buses since 1983, in which the air is cooled directly by humidification and blown into the passenger compartment. Similar systems for cars were sold in a small version under the name vehicle evaporative cooler (English "Swamp-Cooler") under the brand names "Thermadorcarcooler" or "BycoolFlat". Direct adiabatic cooling causes a substantial, often undesirable increase in the air humidity in the passenger compartment to be cooled. In addition, there is an increased risk of harmful germ formation due to direct adiabatic cooling. Indirect adiabatic cooling is currently only used using heat exchangers. For weight and volume reasons, this application is therefore limited to buildings or large vehicles such as buses. Indirectly adiabatic air conditioning using a plate heat exchanger is already known. The air inflow is sent through a heat exchanger in the same way as for the cooling of rooms.

US 2,151,097 describes the cooling of a vehicle in which fresh air is brought into contact with water. Some of the water evaporates, which means that the heat of evaporation is absorbed from the environment and air is cooled via a heat-exchanging surface, which is directed into the cabin. This enables energy-saving cooling to be achieved without enriching the air in the interior too much with moist air. However, it is disadvantageous that the cooling is often inadequate at particularly high outside temperatures. If the heat-exchanging surface is enlarged, this leads to an excessive increase in the vehicle weight, which is disadvantageous and again leads to increased fuel consumption.

In DE 10 2015 003 660 A1, a primary air flow is cooled by the supply of water and an indirect heat exchange is carried out with a fresh air flow, which is introduced into the interior of the vehicle cabin. The heat exchange surface can additionally be cooled by coolant cooled by a compressor machine. However, this is disadvantageous since, on the one hand, the heat exchange surface must be provided to be particularly thick, as a result of which it is difficult to arrange the heat exchanger in the vehicle. In addition, the Heat used to evaporate the supplied water more from the surfaces of the room facing away from the heat exchanger surface, since these are warmer than the heat exchanger surface. This reduces the cooling capacity. Furthermore, fuel is also necessary for the operation of the compressor machine. Such fresh air supply systems also often do not cool adequately at high temperatures.

US 2005/210892 A1 describes a cooling system in which outside air, as the primary fresh air stream, is cooled by a heat exchanger and part of it is led into the interior. The rest of the outside air flow is mixed with water and led to the opposite side of the heat exchanger. The primary fresh air stream is first pre-cooled, then cooled further by supplying water and then brought into heat exchange with the upstream primary fresh air stream. In other words, the outside air flow cools itself by adding water to the downstream half of the outside air flow and cooling the upstream part via a heat exchanger. So it is a fresh air supply with built-in cooling. However, this cooling is often not sufficient to achieve a pleasant interior temperature in the vehicle cabin in hot or humid outside air.

The object of the invention is therefore to provide a vehicle or a method for cooling for a vehicle of the type mentioned above, the cooling of which is fuel-saving and nevertheless efficient.

This is achieved according to the invention in that a primary fresh air stream is pre-cooled and the primary fresh air stream thus pre-cooled is further cooled by supplying water and a primary heat exchange of the cooled primary fresh air stream is carried out with an interior air stream from the interior air of the vehicle cabin.

The object is also achieved in that a primary fresh air duct of the cooling device carrying a primary fresh air flow is connected to a pre-cooling device for cooling the primary fresh air flow, and the primary fresh air duct downstream of the pre-cooling device is connected to at least one primary water introduction device for further cooling of the primary fresh air flow and downstream the primary water introduction device is connected to a first side of a primary heat exchanger, an interior air duct carrying an interior air flow, which has at least one inlet for sucking in interior air of the vehicle cabin of the vehicle and at least one outlet for blowing out the interior air into the vehicle cabin, downstream of the inlet - It is connected to a second side of the primary heat exchanger and is connected to the outlet downstream of the second side of the primary heat exchanger.

The interior air flow is taken from the interior air of the cabin and, after cooling, is at least partially returned to the vehicle cabin.

Pre-cooling allows the primary fresh air flow to be cooled more, which leads to an increase in efficiency. The cooling of the indoor air flow further increases the efficiency, since it does not have to cool particularly hot outside air flowing in from outside, but only the usually somewhat cooler indoor air.

In the case of heat exchange or heat exchangers, it is important that the two gas phases - in the case of primary heat exchange this is the primary fresh air flow and the indoor air flow - and, if present, the liquid phases do not essentially mix with one another, as is the case in classic heat exchanges. shear is the case. In other words, heat exchange means indirect heat exchange.

It can be provided that inside air is removed from the vehicle cabin via an exhaust air flow. Accordingly, it can also be provided that the vehicle has at least one exhaust air duct for removing internal air from the vehicle cabin. This exhaust air flow or this exhaust air duct preferably lead the inside air from the vehicle into the surroundings of the vehicle. The exhaust air duct can preferably be arranged in the area of the rear of the vehicle. Due to the pre-cooling and thus a further reduction in the temperature of the primary fresh air flow, the primary heat exchanger no longer has to be made so large, which leads to a lighter and therefore more fuel-efficient design.

Pre-cooling is preferably achieved by a method which does not lead to an enrichment of the primary fresh air flow with water. This would reduce the efficiency of further cooling.

With the use of adiabatic cooling, a significant improvement in the energy and environmental balance for motor vehicles, a reduction in the health disadvantages due to drafts and a significant improvement in the range for electric vehicles can be achieved.

Since such cooling does not require a compressor, it can also be used when the engine is switched off, for example in start-stop mode the. Any increased latency that may occur until a satisfactory cabin temperature is set can be compensated for by pre-cooling before driving away.

The general method is used both directly by spraying water into an air stream or indirectly by humidifying an air stream other than the air stream to be cooled. Evaporative cooling is a renewable energy because only air and water are used as sources for cooling. The principle of this process is the same as for sweating, in which water evaporates through the sweating. The heat necessary for the evaporation is extracted from the environment, which leads to the fact that the human skin and thus the blood circulation cool down.

With the application of body-integrated adiabatic cooling, a significant improvement in the energy and environmental balance for motor vehicles and, in addition, a significant improvement in the range for electric vehicles can be achieved. Calculations showed that an energy saving for vehicle air conditioning of over 80% and thus a saving of 0.72 million tons of C0 ₂ , 304 million liters of fuel and thus at the same time a significant improvement in the foreign trade balance should be possible (based on cars and small TRUCK). There is further energy saving potential for buses, trucks and freight temperature control.

An advantage over the known systems is that the energy consumption for cooling a vehicle interior from fossil or electrical energy is reduced by a factor of 10, since only the energy for driving a blower is required for cooling. The additional energy required for cooling itself is provided in the form of water and the evaporation heat of 2.26 MJ / kg contained in it, making it very environmentally friendly and inexpensive. The energy required to transport around 5 to 10 liters of water per 100 km for cooling is almost negligible in the overall energy balance of the vehicle or is even compensated for in fossil vehicles by eliminating the cooling unit. Likewise, the costs for the water required, currently around 2.0 EUR per m ³ (as of 2017) across Europe and thus 10 cents, are 2.0 cents compared to the costs of around 150 cents for 1.4 liters of fossil 100 times less fuel. Largely unpurified water is also suitable for use in cooling. At the expense of an increased cleaning effort for the tube system, even salt water could be used. The cooling capacity depends, among other things, on the relative humidity, which means that in most countries cooling is only possible via the system in question, in particular In tropical areas, this system can also be used in combination with conventional, small-sized air conditioning systems for support.

A major advantage of this adiabatic body cooling is that, unlike direct adiabatic cooling, the air that is introduced into the passenger or transport space itself is not humidified. Therefore, there are no problems with nucleation. At the same time, sufficient cooling capacity is provided.

A further significant advance in such a system would be the replacement of climate-damaging coolants, which escape into the atmosphere both in normal operation but also in the event of leaks in the refrigeration circuit due to defects or in the event of accidents.

The regulation of the cooling intensity can take place via a regulation device. When using a fan, this is possible both via on / off and via a speed control to achieve the required amount of air (and thus change the cooling capacity). The regulation can also influence the supply of moisture to the evaporation layer.

Photovoltaic cells, which provide energy for operating the cooling, can also be arranged on the outer skin of the vehicle.

It is particularly advantageous if at least one partial flow is derived from the primary fresh air flow, preferably upstream of the further cooling by supplying water, and the partial flow, preferably downstream of the primary heat exchange, is introduced into the internal air flow. By introducing the partial flow into the indoor air flow, the indoor air is renewed. By introducing the fresh air, which is preferably already pre-cooled, cool, but not too humid, air is introduced - provided that the pre-cooling does not take place through the enrichment of water. The size ratio of the partial flow to the remaining primary fresh air flow is preferably adjustable. This also applies if the primary fresh air duct downstream of the pre-cooling device and preferably upstream of the primary water introduction device is connected to a dividing device, wherein the dividing device is connected to at least one partial flow duct leading from the primary fresh air flow and that the partial flow duct is flow-connected, preferably downstream of the primary heat exchanger.

In a particularly preferred embodiment it is provided that the cooling of the primary fresh air flow is achieved by cooling a secondary fresh air flow by supplying water and a secondary one Heat exchange of the secondary fresh air stream cooled in this way is carried out with the primary fresh air stream. Accordingly, it can also be provided that the pre-cooling device is designed as a secondary heat exchanger and a secondary fresh air duct carrying a secondary fresh air flow is connected to at least one secondary water inlet device for cooling a secondary fresh air flow and downstream of the secondary water injection device to a first side of the secondary heat exchanger and that the primary fresh air duct is connected to a second side of the secondary heat exchanger. This is a particularly energy-efficient variant, since very little energy is used for the pre-cooling. This achieves two-stage adiabatic cooling. This double enrichment of different fresh air flows results in a particularly large increase in efficiency.

The resulting condensate in the course of the heat exchange or through the heat exchanger (s) can be discharged through suitable drainage channels, which can be used for the further cooling of the primary fresh air flow or for the cooling of the secondary fresh air flow.

It can be advantageous here if inner surfaces of the cooling device have a surface which transports liquids such as water in defined directions. Surfaces of this type are particularly useful in the area of water introduction devices, since they can direct the water collecting on the surfaces against gravity in defined directions and thus can distribute the water in the water introduction device. This can also be advantageous on surfaces of the primary or secondary heat exchanger.

Such an effect can be achieved, for example, by channels on the surfaces which have a capillary effect in a defined direction. These channels preferably have a width and / or a depth in the range from 5 pm to 700 pm, at least in sections, in order to achieve a corresponding capillary action. The channels particularly preferably have sections which reduce their width and / or depth along a preferred transport direction of the water, the maximum widths and / or depths of adjacent sections remaining essentially the same. In other words, the channels preferably have a sawtooth pattern of continuously narrowing widths and / or depths along the preferred transport direction, which then widen again suddenly. It has been shown that such forms allow water to be transported particularly effectively in one direction. This can help transport water that collects on the surface to those parts of the surface that are poorly supplied with water. This increased the evaporation surface. Adjacent channels can be over Cross channels must be connected. In addition, it can also be advantageous if the surface is highly hydrophilic, that is to say the formation of water drops is reduced and the formation of a water film is increased.

Surfaces of the type described have already been described in other areas of science and technology ¹ .

A two-stage cooling unit is therefore used, in which outside air is cooled, preferably by injecting via spray nozzles. The air that is cooled and humidified in this way is in turn discharged to the outside and cools another air stream to outside air via a heat exchanger. This still non-humidified air flow is preferably divided at a control flap and a partial flow is diverted. Part of the already cooled air is now humidified and thus cooled further. The air cooled in this way is in turn used to cool the interior air of the vehicle via a heat exchanger. This can be added to the partial flow of the already cooled but not yet humidified supply air in order to bring about a fresh air supply in the passenger compartment.

The fresh air streams and the indoor air stream are preferably moved in the respective channels by means of fans or similar air stream driving means.

It can further be provided that at least the interior air flow is used for surface cooling of at least one interior surface of the vehicle cabin. Accordingly, it can also be provided that at least the interior air duct downstream of the primary heat exchanger is fluidly connected to at least one surface cooling unit for cooling an interior surface of the vehicle cabin. This leads to an additional improvement in the cabin climate, since the perception of temperature also strongly depends on the heat radiation and thus the temperature of the surrounding surfaces. The roof area is particularly suitable for this.

The radiation surface thus shaped can be used both as a pure radiation surface and as a supply air distribution (similar to a perforated ceiling in the climatic area) of the interior air flow by directing the cooled interior air flow into the vehicle cabin.

It is particularly preferred if the interior air flow is returned to the vehicle cabin via the roof of the vehicle cabin, or accordingly,

¹ Comanns P, Buchberger G, Buchsbaum A, Baumgartner R, Kogler A, BauerS, Baumgartner W. 2015 Directional, passiveliquid transport: the Texas horned lizard as amodel for a biomimetic'liquid diode '. JR Soc.lnterface12: 20150415. if the outlet of the interior air duct is arranged on the roof of the vehicle cabin.

Another additional benefit for the comfort of passengers or when transporting sensitive goods or animals arises from the fact that the temperature distribution in the passenger or transport space is more uniform due to the large, cooled area. The lower ambient temperature and thus reduced radiant heat, which affects people, animals and goods, allows a higher air temperature to be used with the same feeling of comfort. The temperature felt by humans is a function of the temperature of the surrounding areas, which act through heat radiation, and the air temperature, which acts through convection. For example, an air temperature of 25 ° C at a temperature of the surrounding surfaces of 25 ° C is also perceived as too warm and would have to be reduced to 21 ° C, while the same air temperature is perceived as pleasant at a lower surface temperature of 21 ° C ( see for example comfort diagram according to Frank and Reiher). As a result, by creating large, cool surfaces with the aid of adiabatic body cooling, the temperature required for a feeling of comfort can be left higher. This can be seen on the basis of comfort diagrams. Since the heat transfer into the interior of the vehicle depends directly on the temperature difference between outside temperature and inside temperature due to heat conduction, additional energy can be saved. For example, the energy transfer by cable is around 40% higher at an outside temperature of 35 ° C and thus a reduction in the interior temperature from 25 ° C to 21 ° C necessary to reach the comfort zone. By using the large-area body cooling system, the cooling energy requirement is significantly lower.

Furthermore, it is largely possible to dispense with blowing in cold air, since a large part of the cooling takes place on the large cooling surface of the body (especially the roof area). Due to the natural convection, in this case the sinking of the cold air from the surface, this happens without unpleasant drafts due to excessive air speeds and evenly. The same applies in the opposite sense to heating if the surface temperature is caused by the heating of the body using surface heating methods such as heating wires or the like. is heated.

In a preferred embodiment, the now-cooled indoor air is not introduced through conventional air inlets, but through a porous roof skin. The air is supplied between the roof skin and an additional radiation surface. The radiation surface consists of foils or other materials that have a particularly high radiation coefficient. By cooling this radiation area, which is drawn in over the entire roof area, the radiation acts on the passengers in the vehicle. According to the invention, the comfort of the passengers is thus improved even at higher air temperatures.

The roof structure is preferably constructed in such a way that the surface facing the outer skin reflects and the surface facing the passenger compartment is transparent to radiation and has the highest possible irradiation value (ie black color).

In addition to the radiation function, this area also preferably takes over the air distribution as a perforated ceiling. Due to the much larger total area of all air outlets compared to conventional air nozzles in the dashboard, the air speed and thus the feeling of draft can be reduced. The design of the air outlets in the ceiling can also be carried out in such a way that, as required, the supply takes place selectively in the head area of the passengers or in the areas surrounding the body.

A further aspect of the invention is the cooling of body parts and surfaces which face the passenger or transport space, preferably by means of the interior air flow or another air flow such as the primary or secondary fresh air flow, preferably by direct air flow. The surface temperature of the vehicle interior can be reduced in large temperature ranges simply by flowing through a surface cooling unit with cooling elements or cooling fins with uncooled air in the ambient temperature range. The body shell, warmed up by the radiant heat of the sun, which increases the surface temperature of the interior in conventional vehicles, is removed by simply flowing air through it. The water injection device can even be switched off temporarily because, especially in transitional periods between summer and winter, moderate outside temperatures of the air are sufficient in moderate latitudes to cool down the interior surface temperature.

By lowering the temperature of the surfaces surrounding the occupants, air cooling can be reduced to a minimum, since the air temperature can be kept higher without reducing comfort due to the reduced radiant heat. This simple operating mode can thus achieve considerable energy savings. Likewise, with this use, the air flowing through the cavity can be cooled beforehand in a closed circuit or in an open system, in order to further reduce the air flow To achieve surface temperature of the cooling elements and thus possibly also direct cooling of the passenger or transport space temperature via natural convection, which likewise has a lower flow rate and is therefore health-friendly compared to conventional air conditioning systems.

In contrast to the previously known systems for indirect adiabatic cooling, there is no need for a heat exchanger located under the hood, but parts of the body can be used for direct cooling of the air flow, but preferably also of the passenger compartment, without direct cooling of an air flow. This reduces the weight, manufacturing costs and maintenance costs of the vehicle.

In order to achieve increased cooling, it can be provided that at least the secondary fresh air flow, the primary fresh air flow or the inside air flow are additionally cooled via a further cooling device, preferably via a compressor cooling device. Accordingly, it can also be provided that at least the secondary fresh air duct, the primary fresh air duct or the inner air duct is connected to a further cooling device, preferably to a compressor cooling device. If the compressor cooling device is arranged in the primary fresh air flow, it can serve as a pre-cooling device, that is to say as a pre-cooling device or as an additional cooling element. In principle, the vehicle described can also have a conventional cooling system with a compressor cooling device parallel to the cooling device described.

It can be provided that the primary heat exchange is carried out in the roof of the vehicle cabin. Accordingly, it can also be provided that the primary heat exchanger is arranged on the roof of the vehicle. The roof offers plenty of space for heat exchange. The arrangement on the roof also allows the inner surface of the roof to be cooled at the same time, which means that even more heat can be removed from the vehicle cabin. The heat of the inner surface is absorbed directly by the side of the heat exchanger bordering it and the current running therein. This can be the primary fresh air flow or the indoor air flow. The interior air flow is preferably selected, as a result of which it can at least partially be introduced into the cabin space via the roof skin via nozzles or openings.

For this purpose, it can also be provided that the secondary heat exchange in the roof of the vehicle cabin and the primary heat exchange between the secondary heat exchange and the vehicle cabin are carried out, or accordingly that the secondary heat exchanger is arranged on the roof of the vehicle, the primary heat exchanger being between the secondary heat exchanger and the Vehicle cabin is arranged. This is particularly space-saving. Furthermore, the fresh air can be sucked in directly in the area of the roof, which can also make things easier. It can be provided that the main flow directions of the secondary and primary heat exchangers have essentially opposite directions or the same direction.

In a preferred embodiment it is provided that the primary heat exchange is carried out via a primary heat exchanger which extends flatly along the roof of the vehicle. Accordingly, it can also be provided that the primary heat exchanger extends flatly along the roof of the vehicle. This enables effective use of the surface. In addition, an additional heat exchange with the inner surface of the roof is improved, which leads to an improved cooling of this inner surface. If a secondary heat exchange is provided, this can be carried out, for example, using a compact secondary heat exchanger. This secondary heat exchanger can be arranged anywhere in the vehicle, for example in the rear.

It is also advantageous if the secondary heat exchange is carried out via a secondary heat exchanger which extends flatly along the roof of the vehicle. Accordingly, it is also advantageous if the secondary heat exchanger extends flatly along the roof of the vehicle.

It can also be advantageous that the secondary heat exchange and the primary heat exchange, and preferably also the cooling of the secondary fresh air flow and the primary fresh air flow, are carried out by supplying water in a common heat exchanger block. Accordingly, it can also be provided that the secondary heat exchanger and the primary heat exchanger, and preferably also the secondary water injection device and the primary water injection device, are designed as a common heat exchanger block. This enables a compact structure, whereby a heat transfer between the heat exchangers can be used positively. It can preferably be provided that the primary water injection device and the primary heat exchanger overlap along the flow directions, that is to say that at least parts of the primary water injection device are arranged in the primary heat exchanger. This is also possible for the secondary water injection device and secondary heat exchanger. This enables a particularly compact design and effective cooling.

It can be provided that the water is applied directly to the surfaces of the primary or secondary heat exchanger. This will improve Allows heat transfer and distributes the water over a large surface so that it can evaporate well. This also increases the cooling capacity.

The water is preferably injected into the fresh air or into the fresh air duct. It is particularly advantageous if the water is injected in the form of water drops or in the form of a water mist.

At least one heat exchanger preferably has a surface with surface-enlarging surface structures. These structures particularly preferably comprise channels in the main flow direction.

The present invention is explained in more detail below on the basis of non-restrictive design variants shown in the figures. Show it :

Fig. La shows a first embodiment of a vehicle according to the invention in a schematic side view;

Fig. Lb shows a second embodiment similar to the first embodiment in a schematic side view;

2 shows a schematic structure of a third embodiment of a cooling device according to the invention in a block diagram;

3 shows an embodiment of a common heat exchanger block according to the invention.

FIG. 1 a shows a vehicle 1 designed as a passenger car with a vehicle cabin 3 and a cooling device 2, which uses the method according to the invention. The cooling device 2 has a water tank 20 for storing water in the rear area of the vehicle 1 and a primary heat exchanger 4, which is arranged in the roof 10 of the cabin 3 and extends along the surface of the roof 10 over the majority of its surface. The primary heat exchanger 4 has a first side 4a and a second side 4b, which are separated by wall structures 4c which are only partially and schematically indicated. This results in a plurality of parallel channels which are connected to one another at the ends and have an essentially triangular cross section, both for the first and for the wide side 4a, 4b. The second side 4b, through which an interior air flow 8b of an interior air duct (not shown) is guided, is arranged on the side of the interior surface 10a of the roof 10. Through outlets 13 in the roof structure, the interior air flow 8b can preferably be returned to the cabin toward the end of the second side 4b of the primary heat exchanger 4. A primary water introduction device 5, which is shown only schematically in FIG. 1, is arranged in the region of the primary heat exchanger 4 at one end and moistens it Wall structures 4c on the first side 4a with water from the water tank 20. The primary heat exchanger 4 thus at least partially also acts as part of the primary water introduction device 5.

This arrangement not only cools the inside air flow 8b but also the inside roof surface 10a. The primary heat exchanger 4 thus acts as a surface cooling device. The inner surface 10a is preferably black on the side facing the cabin in order to enable the best possible heat exchange. The inner walls of the heat exchanger 4 are preferably also black.

The first side 4a of the primary heat exchanger 4 is supplied by a fan 11 with fresh air drawn in from outside the vehicle. The fan 11 draws in the fresh air from the outside and blows this primary fresh air flow 6b via a primary fresh air duct 6a into a compressor cooling unit 12, which serves as a pre-cooling device. There, the fresh air flow 6b is pre-cooled and passed on from the fresh air duct 6a to the primary water introduction device 5 and to the second side 4b of the primary heat exchanger 4. After the heat exchange, the primary fresh air stream 6b is discharged into the outside air again. The primary fresh air flow 6b thus flows essentially on the roof 10 from the rear in the direction of the vehicle front or the windshield. The internal air flow 8b is conveyed by a suitable fan, preferably in the opposite direction, from the front end of the roof 10 in the direction of the rear through the labyrinth of the primary heat exchanger 4. The primary heat exchanger 4 is thus operated in the counterflow principle. Alternatively, it can also be operated using the same principle. In the area of the rear, the second side 4b and thus the interior air duct 8a have outlets 13 which blow the interior air flow 8b into the vehicle cabin 3.

A photovoltaic system 14 is arranged on the outer skin of the roof 10 and produces electricity from sunlight in order to support the operation of the cooling device 2.

Fig. Lb shows a variant very similar to the first embodiment. Therefore, only the most important differences are dealt with here. The primary heat exchanger 4 and a secondary heat exchanger 14, which serves as a pre-cooling device, are designed as a common heat exchanger block 21. It is arranged in the rear of the vehicle 1, in the area of the water tank 20. The fresh air for the heat exchangers 4, 14 is drawn in and discharged from the rear (arrows 22). After cooling, the inside air flow 8b is conducted via the inside air duct 8a from the heat exchanger block 21 in the direction of the roof 10, where a surface cooling unit 19 is arranged which extends across the roof 10. This cools the inner surface 10a, at the same time it preferably has in particular or exclusively in the front region of the roof 10, that is to say in the region of the vehicle front, outlets 13 in the form of nozzles which direct the interior air flow 8b into the vehicle cabin 3.

2 shows a construction of a cooling device 3 according to the invention, which also uses the method according to the invention. First, a secondary fresh air flow 7b - guided in a secondary fresh air duct 7a - is conducted into a secondary water introduction device 9, in which water is fed to it and it is thus cooled. The cooled secondary fresh air flow 7b is then passed further into the first side of a secondary heat exchanger 14 and thus cools the warmer primary fresh air flow 6b, which is directed into the second side of the secondary heat exchanger 14 via a primary fresh air duct 6a. The secondary heat exchanger 14 thus represents the precooling device and the primary fresh air stream 6b is precooled. The secondary fresh air stream 7b can then be discharged into the circulating air around the car again.

The primary fresh air duct 6a is connected downstream of the secondary heat exchanger 14 to a dividing device 15 which branches off a partial stream 16 from the primary fresh air stream 6b and discharges it into a partial flow duct 17. The ratio of the partial flow 16 to the remaining primary fresh air flow 6b can preferably be set by the passenger. The remaining fresh air stream 6b is fed into the primary water introduction device 5, which feeds water to the pre-cooled, but still dry primary fresh air stream 6b and thus cools it. The now particularly cool and moist primary fresh air stream 6b is directed to the primary heat exchanger 4, namely on its first side 4a.

An interior air flow 8b extracted from an inlet 18 in the interior of the vehicle cabin 3, which is guided in the interior air duct 8a, is conducted into the second side 4b of the primary heat exchanger 4 and thus cooled by the primary fresh air flow 6b. The primary fresh air stream 6b can then be discharged back into the circulating air around the car. The interior air stream 8b, which is cooled so well, is combined with the partial stream 16, as a result of which fresh air is mixed in the cool but not too moist and is passed back into the vehicle cabin 3 via the outlet 13.

This embodiment can be expanded by one or more surface cooling units. This can be fed from the primary or secondary fresh air flow 4b, 7b or from the indoor air flow 8b or from partial flows which have been branched off from these. The primary or secondary fresh air flow 4b, 7b can, for example, be arranged upstream or downstream of the heat exchangers 4, 14. FIG. 4 shows a common heat exchanger block 21, as can be installed in FIG. 1b. The heat exchanger block 21 not only includes primary and secondary heat exchangers 4, 14 but also the primary and secondary water injection devices 5, 9.

The secondary fresh air flow 7b is introduced at an upper side 23 into the first side of the secondary heat exchanger 5. A secondary water introduction device 9 arranged on the second side guides water into the secondary heat exchanger 5 and thus cools the secondary fresh air stream 7b. The secondary fresh air flow 7b is guided through the heat exchanger to an underside 24 and removed. The primary fresh air flow 6b is introduced in the middle and is guided through the second side of the secondary heat exchanger 9 across the heat exchanger 9. A cross flow principle is thus achieved and this fresh air flow 6b is precooled.

The pre-cooled primary fresh air stream 6b is then led to the other side of the heat exchanger block 21 and passed into a first side 4a of the primary heat exchanger 4. A partial flow can possibly be branched off beforehand. A primary water inlet device 5 guides water into the first side 4a and thus cools the pre-cooled primary fresh air stream 6b. The internal air flow 8b introduced on the second side 4b is cooled - likewise according to the cross-flow principle - by the primary fresh air flow 6b, possibly mixed with a partial flow and passed back into the vehicle cabin 3. In this embodiment it can be seen that the water inlet devices and the heat exchangers can interact or can even be arranged at the same flow level. A part of the heat exchanger can even extend upstream of the water inlet device, but in any case it is necessary that at least part of the heat exchanger is also located downstream of the highest point of the water inlet device.

The primary heat exchanger 4 and the secondary heat exchanger 14 are thus separated by a partition 25. This partition 25 can be thermally insulated.

Claims

PATENT CLAIMS

1. Method for cooling a vehicle cabin (3) of a vehicle (1), wherein a primary fresh air stream (6b) is pre-cooled and the primary fresh air stream (6b) thus pre-cooled is further cooled by supplying water and a primary heat exchange of the cooled primary one Fresh air flow (6b) is carried out with an inside air flow (8b) from the inside air of the vehicle cabin (3).

2. The method according to claim 1, characterized in that at least a partial flow (16) is derived from the primary fresh air flow (6b), preferably upstream of the further cooling by supplying water, and the partial flow (16), preferably downstream of the primary heat exchange , is introduced into the indoor air flow (8b).

3. The method according to claim 1 or 2, characterized in that the cooling of the primary fresh air flow (6b) is achieved in that a secondary fresh air flow (7b) is cooled by supplying water and a secondary heat exchange of the secondary cooled in this way Fresh air flow (7b) is carried out with the primary fresh air flow (6b).

4. The method according to any one of claims 1 to 3, characterized in that at least the interior air flow (8b) is used for surface cooling of at least one interior surface (10a) of the vehicle cabin (3).

5. The method according to any one of claims 1 to 3, characterized in that the interior air flow (8b) via the roof (10) of the vehicle cabin (3) is returned to the vehicle cabin (3).

6. The method according to any one of claims 1 to 5, characterized in that at least the secondary fresh air stream (7b), the primary fresh air stream (6b) or the indoor air stream (8b) are additionally cooled via a further cooling device, preferably via a Compressor cooling device.

7. The method according to any one of claims 1 to 6, characterized in that the primary heat exchange in the roof (10) of the vehicle cabin (3) is carried out.

8. The method according to claim 7, characterized in that the secondary heat exchange in the roof (10) of the vehicle cabin (3) and the primary heat exchange between the secondary heat exchange and the vehicle cabin (3) is carried out.

9. The method according to any one of claims 7 or 8, characterized in that the primary heat exchange is carried out via a primary heat exchanger (4) extending flatly along the roof (10) of the vehicle (1).

10. The method according to claim 8 or 9, characterized in that the secondary heat exchange is carried out via a secondary heat exchanger (9) extending flatly along the roof (10) of the vehicle (1).

11. The method according to any one of claims 3 to 6, characterized in that the secondary heat exchange and the primary heat exchange, and preferably also the cooling of the secondary fresh air flow (7b) and the primary fresh air flow (6b) by supplying water in a ge - Common heat exchanger block (21).

12. Vehicle (1) with a cooling device (2) for cooling a vehicle cabin (3), a primary fresh air duct (6a) of the cooling device (2) leading a primary fresh air flow (6b) with a pre-cooling device for cooling the primary one Fresh air flow (6b) is connected, and the primary fresh air channel (6a) downstream of the pre-cooling device with at least one primary water introduction device (9) for further cooling of the primary fresh air flow (6b) and downstream of the primary water introduction device (9) with a first side (4a) of a primary heat exchanger (4), an interior air duct (8a) carrying an interior air flow (8b), the at least one inlet (18) for sucking in interior air of the vehicle cabin (3) of the vehicle ( 1) and at least one outlet (13) for blowing out the interior air into the vehicle cabin (3), downstream of the inlet (18) with a second side (4b) of the primary heat exchanger (4) and downstream of the second side (4b) of the primary heat exchanger (4) is connected to the outlet (13).

13. Vehicle (1) according to claim 12, characterized in that the primary fresh air duct (6a) downstream of the pre-cooling device and preferably upstream of the primary water introduction device (5) is connected to a dividing device (15), the dividing device (15 ) is connected to at least one partial flow channel (1) leading from the partial fresh air flow (6b) branched partial flow (15) and that the partial flow channel (17) with the interior air channel (8a) preferably flow-connected downstream of the primary heat exchanger (4) is.

14. Vehicle according to claim 12 or 13, characterized in that the pre-cooling device is designed as a secondary heat exchanger (14) and a secondary fresh air duct (6a) leading a secondary fresh air flow (6b) with at least one secondary water introduction device (9) for cooling a secondary fresh air flow (6b) and downstream of the secondary water injection device (9) is connected to a first side of the secondary heat exchanger (14) and that the primary fresh air duct (6a) connects to a second side of the secondary heat exchanger (14) - is bound.

15. Vehicle (1) according to one of claims 12 to 14, characterized in that at least the interior air duct (8a) downstream of the primary heat exchanger (4) with at least one surface cooling unit (19) for cooling an interior surface (10a) of the vehicle cabin (3) is connected to the flow.

16. Vehicle (1) according to one of claims 12 to 15, characterized in that the outlet (13) of the interior air duct (8a) is arranged on the roof (10) of the vehicle cabin (3).

17. Vehicle (1) according to one of claims 12 to 16, characterized in that at least the secondary fresh air duct (7a), the primary fresh air duct (6a) or the inner air duct (8a) is connected to a further cooling device, preferably one compressor cooling device.

18. Vehicle (1) according to one of claims 12 to 17, characterized in that the primary heat exchanger (4) on the roof (10) of the vehicle (1) is arranged.

19. Vehicle (1) according to claim 18, characterized in that the secondary heat exchanger (14) is arranged on the roof (10) of the vehicle (1), the primary heat exchanger (4) between the secondary heat exchanger (14 ) and the vehicle cabin (3) is arranged.

20. Vehicle (1) according to one of claims 18 or 19, characterized in that the primary heat exchanger (4) extends flat along the roof (10) of the vehicle (1).

21. Vehicle (1) according to one of claims 14 to 20, characterized in that the secondary heat exchanger (14) extends flat along the roof (10) of the vehicle (1).

22. Vehicle (1) according to one of claims 14 to 17, characterized in that the secondary heat exchanger (14) and the primary heat exchanger (4) and preferably also the secondary water injection device (9) and the primary water injection device (5) as common heat exchanger block (21) are executed.

2019 06 17th

MT