Abstract:
This invention entails an air conditioning device ( 2 ) for cooling an electronic device cabinet or the like. It is equipped with a housing, an air supplying device ( 10 ) and a heat exchanger ( 4 ). The air supplying device ( 10 ) sucks air in from one side and conducts it through a heat exchanger ( 4 ) to a second side ( 14 ) and supplies it in radial direction to the second side ( 14 ). The heat exchanger ( 4 ) is connected so as to impact with its external or internal cooling device the heat exchangers with cooled cooling medium. The outgoing current of radially streaming air is applied to front surface of adjacent electronic device cabinets so that the air can thus be used without being substantially mixed in advance with warmer air. The air can also be sucked in by the electronic device cabinets and used for cooling without losses of efficiency levels.

Description:
[0001]    This application for patent claims priority from European patent application EP 10 010 196.3, filed Sep. 22, 2010, and the contents of that prior application are incorporated herein in their entirety. 
       TECHNICAL FIELD 
       [0002]    The invention relates to an air conditioning device for cooling air for an electronic device cabinet or the like. 
       BACKGROUND OF THE INVENTION 
       [0003]    Electronic devices are commonly accommodated in computer centers and production facilities in cabinets for electronic devices (also known as “racks”) which have standardized modular dimensions, for example 19 inches. These cabinets often provide sufficient amount of space for a plurality of electronic devices which are tightly stacked on top of another. In addition to supplying the necessary electric power and data, the electronic devices must be also sufficiently cooled to ensure their correct operation. For cooling purposes are usually employed air conditioning devices which are essentially used to supply cooling air, which is conducted by means of air supplying devices through the electronic devices so that heat is removed in this manner from electronic components. As the computing power is becoming more and more concentrated per unit of space, the result is a requirement to enable the accommodation of air conditioning device in the most effective manner in order to make it possible to provide reliably and constantly cooling air in sufficient amounts, without requiring a large amount of space for installation. Known air conditioning devices are customarily equipped with simple cooling mechanisms, which are based for example on an evaporator cooling circuit. 
         [0004]    Cabinets for electronic devices are arranged in modern computer centers in several rows arranged next to each other in the available space at a certain distance between them, while the front sides of the cabinets for electronic devices can be arranged so as to face cabinets for electronic device in an adjacent row. The front sides are often provided with air inlets which are designed to suck in cooling air from a so called “cool duct”. The air which is warmed up by the electric devices is then supplied at the rear side from the cabinets for electronic devices into a so called “warm duct”. It is thus necessary in this case to provide at least an air conditioning device which supplies the cooling air into the cool ducts, for example air from the warm ducts which has been cooled down. It is know that cold air can be blown into a cool duct through floor discharge outlets. It is further also known that air conditioning devices can be arranged between the cabinets for electronic devices so that the cooling air is blown in from the air conditioning devices arranged between the electronic device cabinets at right angle to the front of adjacent electronic device cabinets. This concept is a based on the open cooling concept. 
         [0005]    Closed architectures are also known. In this case, an electronic device and an air conditioning device of this type cabinet are located in a closed jacket or in a common housing. 
         [0006]    An apparent disadvantage of air conditioning device according to prior art is that the air which is cooled by the air conditioning devices is not supplied in an ideal manner by an air conditioning device based on the open cooling system to the electronic devices to be cooled. When the known outlets are used, the supplied cooling air is mixed with warmed up air before it can be finally used when it is sucked in at the fronts of the electronic device cabinets for cooling of the electronic devices. 
       SUMMARY OF THE INVENTION 
       [0007]    The purpose of the invention is therefore to propose an air conditioning device of the type described in the introduction, which can reduce or eliminate the disadvantages described above. In particular, an objective of the invention is to propose an air conditioning device, wherein although it is designed as a separate, independent unit, the air is guided particularly effectively to the electronic device cabinets so that the supplied cooling air can be absorbed for cooling by the individual electronic devices. 
         [0008]    This task is achieved with the air conditioning device having the characteristics of the independent claim  1 . Advantageous embodiments are described in dependent claims. 
         [0009]    According to a first aspect of the invention, the air conditioning device is provided with a housing having a first side and a second side oriented in such a way that that air is sucked in at the first side and blown out as cooled air at the second side. The first side and the second side of the air conditioning device according to the invention are in this case arranged opposite one another so that the air conditioning device according to the invention can be arranged between electronic device cabinets, and so that cooling air is available which can be used on the second side in the electronic device cabinets. This is available in particular for the open air cooling concept with warm and cool ducts between rows of electronic device cabinets. 
         [0010]    According to a second aspect of the invention, the second side of the air conditioning device according to the invention is equipped with an air supplying device which guides the cooling air in radial direction outward. The radial direction in this case means a direction that is substantially perpendicular to an axis between the first side and the second side. On the first side is thus located an axial air current, which is provided in the air conditioning device according to the invention and which is conducted to a radially directed discharging of the air current on the other side. 
         [0011]    According to a third aspect of the invention, a cooling device is located between the first side and the second side of the air conditioning device according to the invention, which cools the axial inflow of air before the air leaves again the air conditioning device in radial direction. 
         [0012]    Essentially, the air conditioning device according to the invention makes it possible to provide in this manner a cooling stream for the open air cooling concept. For a particularly effective air outflow which results in an ideal absorption by the adjacent electronic devices, the depth of the air conditioning device according to the invention is preferable adjusted so that the air supplying device or an air outlet of the air conditioning device according to the invention are extended through the fronts of adjacent electronic device cabinets, or so that the air supplying device is extended on the second side of the air conditioning device according to the invention from the front level in such a way in the radial direction that the radial stream runs parallel and at a negligible distance along the fronts of the adjacent electronic device cabinets. A particularly advantageous feature is in this case the fact that the exiting cooling stream displays the tendency to move along the surfaces of adjacent electronic device cabinets and to be positioned on the surfaces instead of becoming detached, so that it can then move further in the originally impacted direction of the air flow. The effect of the attachment of the air flow is known as Coanda effect according to the inventor of this effect Henri Coanda. Due to this adjoining current, the radially outgoing cooling air flow is not directed freely into the space available in several electronic device cabinets, where it can become mixed with warmer air. Instead, the electronic device cabinets adjacent to the air conditioning device according to the invention are directly impacted by a current of colder air, for example on their front surfaces, which means that corresponding air supplying devices supply directly almost exclusively pure cooling air, which is absorbed in the electronic device cabinets and which can be used for cooling of the electronic devices. 
         [0013]    In spite of the fact that the open concept of cooling with air has been realized with independently and separately designed air conditioning device, the efficiency of the air conditioning device according to the invention is clearly improved over known air conditioning devices because the utilized cooling output does not have to overcome constant losses which are caused by the mixing with warmer air since instead, almost the entire cooling output provided by the air conditioning device can reach the electronic devices to be cooled. 
         [0014]    Another particular advantage of the construction of the air conditioning device according to the invention is based on the fact that a cooling system which has several air conditioning devices can be very easily scaled, since it is possible for example to arrange very easily additional air conditioning devices next to locations particularly exposed to heat loads (so called “hot spots”), which can supply directly additional cooling air without requiring modifications of the carriers of the electronic devices. 
         [0015]    The air supplying device is designed in a preferred embodiment of the invention as a radial fan, which is extended outward from the second side of the air conditioning device according to the invention, so that an air current entering axially the air conditioning device is guided out in the radial direction parallel to a boundary surface of the second side. 
         [0016]    It is preferred when the rotational speed of the air conditioning device and thus also the resulting air volume stream can be regulated so that the cooling output can be read out individually and made available for the devices to be cooled. Brushless direct current motors are particularly suitable for operating fans because these motors are particularly effective and they are characterized by a high efficiencies level under full load conditions. 
         [0017]    It is particularly preferred when the air conditioning device according to the invention is equipped with at least one temperature sensor, which is positioned such that it detects the temperature of the outgoing cool air or of the incoming warmed air. This makes it possible to realize the regulation of the rotational speed of the air supplying device and/or of the cooling performance. 
         [0018]    In another development of a preferred embodiment, the air conditioning device according to the invention is provided with an interface for at least one temperature sensor located an adjacent device which is to be cooled. The temperature on the rear side of an adjacent device to be cooled, typically a cabinet for electric devices, or an electronic device in an electronic device cabinet, can be used in order to regulate the volume of the air current and/or of the heat exchanger. The feedback of the temperature measured in an adjacent device can be used for example to prevent the situation when the cooling output that is available is not sufficient for cooling of a device which requires a particularly high output. 
         [0019]    Several radial fans are distributed in an advantageous embodiment of the invention throughout the second side of the air conditioning device according to the invention, so that a radial air stream is created as uniformly as possible throughout the entire height of the construction of the air conditioning device according to the invention. In addition, each individual radial fan can be preferably realized with an individual construction height for regulation of the supply of air or of the temperature of the returning air by using individual rotational speeds, or by regulating the volume of the air current generated in this manner. Several temperature sensors can be placed for this purpose throughout the height of the air conditioning device according to the invention, so that an individual adjustment to cooling requirements can be ensured throughout the entire construction height. In a particularly preferred embodiment, the heat exchanger is provided with several heat exchanger segments, so that an associated controllable heat exchanger segment belongs to each radial fan. This means that not only each radial fan can be regulated individually, but that the associated heat exchange segments can be also controlled. 
         [0020]    In a preferred embodiment of the invention, the air conditioning device is provided on the second side with a projecting frame in which the air supplying device is arranged. This serves to protect the air supplying device from mechanical damage since due to the design according to the invention of the adjacent electronic device cabinets which are integrated at the front level, the device stands out from the electronic device cabinets at the uniform front level, so that the device is thus exposed to significant damage. It is preferred when the projecting frame is provided with a wire mesh which enables lateral discharging of cooling air. 
         [0021]    According to a preferred embodiment of the invention, the air conditioning device is equipped with conducting elements which are used for a defined adjustment and harmonization of the outgoing stream of cooling air. These elements can be arranged for example in a projecting frame such as the one mentioned above, for example on its lateral surfaces. The conducting elements can be further also used for an overall adjustment of the radial discharging of the cooling air on the side of the air conditioning device according to the invention, for example if an electronic device cabinet is arranged only on one side of the air conditioning device. 
         [0022]    According to a preferred embodiment of the invention, such conducting elements can be adjusted in such a way that the Coanda effect can occur in a nearly ideal manner, for example with a strong concentration of the outgoing air current, or with an adjustment to potential curves in the front sides of adjacent cabinets for electronic devices. 
         [0023]    According to a preferred embodiment of the invention, the air conditioning device is equipped with a cooling device which can cool the incoming warm air. The cooling device can also be used as a separate device for active generation of cooling, which can be arranged for example directly inside the cooling device according to the invention. As an alternative, the cooling device could be also designed only as a heat exchanger which impacts another location with a central cooled medium in order to cool warm air passing through it. 
         [0024]    When an active cooling device is used, it is also advantageous when this device is provided with an RPM-regulated compressor. This permits to regulate the cooling output so that the energy costs are reduced and the energy efficiency of the device can be further improved. When brushless direct current motors are used, a very high efficiency level can be achieved also under full load conditions. 
         [0025]    The regulation of the fan rotations and of the compressors can be realized by means of a single central control unit which is controlled and influenced through a control terminal. The control unit could be used to fine-tune the level of the voltage which is used to operate the controlled component, or as an alternative, it could use a frequency of the voltage, or a control variable could be output in another alternative, which is then compared by decentralized control units in or on the components to be regulated to nominal variables. 
     
    
     
       BRIEF DESCRIPTION OF FIGURES 
         [0026]    Other characteristics, advantages and possible applications of the present invention will be evident from the description of embodiments and figures below. At the same time, all described and/or illustrated characteristics are can be used independently and in any combination with the subject of the invention, including independently of their composition in individual claims, or independently of their retroactive applications. Further, the same reference symbols are used in the figures for the same or similar objects. 
           [0027]      FIGS. 1   a ,  1   b ,  1   c ,  1   d ,  1   e  and  1   f  show a first embodiment of the air conditioning device according to the invention. 
           [0028]      FIGS. 2   a,    2   b,    2   d,    2   e  and  2   f  show a second embodiment of the air conditioning device according to the invention. 
           [0029]      FIGS. 3   a,    3   b,    3   c  and  3   d  show a conceptual rendering of an air conditioning device, wherein  FIG. 3   d  shows an air conditioning device in installed state. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0030]      FIG. 1   a  shows an air conditioning device  2  according to the invention in a first side view. The air conditioning device  2  comprises an air-liquid heat exchanger  4 , which is connected with lines  6  to a central cooling unit, not shown in the figure, supplying a cooled cooling medium. Air, which is located at a first side  8  shown on the right side of the illustration representing the rear side of the air conditioning device according to the invention, is sucked by means of a radial fan  10  which serves as an air supplying device into the air conditioning device, and it flows onto the heat exchanger  4  which is impacted by cooling medium so that the air is cooled in this manner and then exits the air conditioning device through openings  12  created in a side wall of the air conditioning device  1  according to the invention. This means that air is streamed onto the first side  8  of the air conditioning device  2  of the invention, where it is cooled so that it flows in the direction of the second side  14  of the air conditioning device  2  according to the invention, where it is diverted essentially by 90° by radial fans  10  and streamed radially, which is to say substantially parallel to the extension direction of the second side  14  so that it flows again out of the air conditioning device  2 . 
         [0031]    The openings  12  may be realized in the form of a grid, which has grid openings and which covers one part of the air conditioning device  2 , for example in order to protect the fans  10  from damage. 
         [0032]    The air conditioning device  2  according to the invention is designed in such a way so that it can be preferably built in between or next to electronic device cabinets, while a front outlet region  16  having side openings  12  is distinctly extended from the front sides of the electronic device cabinets, so that the air flowing from the openings  12  can be swept along and applied to the front sides of the electronic device cabinets. Thanks to the independence of the air conditioning device according to the invention, it is not necessary to implement any further modifications of the adjacent electronic device cabinets in order to realize particularly effective cooling. 
         [0033]    As one can see clearly from the front view of the air conditioning device  2  indicated in  FIG. 1   b , particularly advantageous cooling of adjacent electronic device cabinets can be achieved with a relatively small width. The air conditioning device  2  according to the invention requires a very small width in comparison to conventional electronic device cabinets. 
         [0034]    As one can see from the illustration in  FIG. 1   c , the heat exchanger  4  is arranged inclined in the air conditioning device  2  according to the invention, so that a sweeping air stream can flow through a relatively large surface of the heat exchanger  4 . 
         [0035]    Further,  FIG. 1   d  shows a top view of the components of the air conditioning device which are visible in  FIGS. 1   a  through  1   b , wherein it is in particular evident here that the heat exchanger  4  is arranged inclined, that is to say inclined at an angle to an axis between the first side  8  and the second side  14 . The active surface of the heat exchanger  4  can be maximized with a particularly effective use of the available volume. 
         [0036]    Finally,  FIGS. 1   e  and  1   f  show two different isometric projection views of the first embodiment of the air conditioning device  2  according to the invention. The grid  12  is removed for better visibility so that the fans  10  can be freely observed. In order to prevent damage and contamination, the first side  8  is covered with an inlet grid  18 , which can be for example suspended on hinges  20  to enable access to the lines  6  and to other components of the air conditioning device. Finally, a control unit  22  is arranged on the second side  14  for controlling the air conditioning device  2  according to the invention, which can be used for example to control the arrangement of the valves of the lines  6  in order to fine-tune the streaming of the cooling medium through the device and thus the individual cooling output as required. 
         [0037]    The lines  6  lead in one example into a bottom  24 , and they are extended up to an upper cover  26  so that connecting lines can be employed above or below the air conditioning device  2  according to the invention. 
         [0038]    A second embodiment of an air conditioning device according to the invention is shown in the  FIGS. 2   a  through  2   f . An essential difference between the air conditioning device  2  of the invention according to the first embodiment and according to this embodiment is that a compact, active cooling device  30  is integrated in this embodiment. This is suitable in particular for small computer centers, or for stand-alone electronic cabinets such as those that are used in production environments when a central cooling facility is not practical for economic reasons for supplying heat exchangers with a cooled cooling medium. The air conditioning device  30 , which is indicated here only schematically, could be for example based on an evaporator cooling circuit know from refrigerators. An air-fluid heat exchanger  32  is impacted by a fluid cooled by the cooling device  30  so that the air is subjected to cooling as it flows from the from the first side  8  to the second side  14 . The air-fluid heat exchanger  32  may be arranged in the air conditioning device  28  according to the invention as shown, without being inclined at an angle for space reasons, although the cooling device  30  could also occupy the installation space for the tilted installation type, which, however, would be compensated for with a somewhat greater depth of the air-fluid heat exchanger. 
         [0039]    Nevertheless, the second embodiment of the air conditioning device  28  according to the invention can be also provided with a relatively narrow width in comparison to customary cabinets for electronic devices as one can clearly see from  FIG. 2   b.    
         [0040]    Finally,  FIGS. 2   e  and  2   f  show the second embodiment of the air conditioning device  28  according to the invention in two different isometric projection views which make it possible to see inside the inner construction of the device. As was described above, the principle according to the invention is based on the fact that an air conditioning device  2  or  28  according to this invention enables open air cooling for cooling of electronic device in adjacent electronic device cabinets, while disadvantages known from prior art can be eliminated at the same time. This can be achieved in that an outlet region  16  of an air conditioning device  2  or  28  according to the invention is provided in front of the adjacent electronic cabinets, so that cooling air is blown out radially along the front sides of these adjacent electronic device cabinets. The current of cooling air is thus blown directly at the front sides of the electronic devices, which must be sucked only into the corresponding electronic device cabinets to achieve cooling. The principle of the Coanda effect, which describes the application of a current to surfaces, is thus used according to the invention. 
         [0041]    This principle will now be further explained with reference to  FIGS. 3   a  through  3   d .  FIGS. 3   a  through  3   c  shows embodiment 2 or 28 in a schematic view. The first side  8 , which is to say the rear side of the of the air conditioning device  2  or  28  according to the invention, is oriented toward a so called “warm duct” with the used, warmed up cooling air, while the second side  14 , which is to say the front side, is oriented toward the “cool duct” with fresh, cooled cooling air. Optionally, the temperature of the air streaming in can be measured by means of temperature sensors  9  to enable regulation of the rotational speed of the radial fan  10  as required. In  FIG. 3   b  are indicated several temperature sensors  9 , which are distributed throughout the construction height of the air conditioning device  2  according to the invention, and which thus allow individual adjustments of the rotational speed of all radial fans. As an alternative or in addition, it would be in this context also conceivable to arrange one or several temperature sensors on the discharging side of the heat exchanger. It is particularly advantageous when temperature sensors are arranged on the rear side of the adjacent electronic device cabinets to be cooled at different heights, so that the temperature data measured in this location is then used to regulate jointly or individually the rotational speed of the radial fans  10  and/or so that the heat exchanger segments are also individually regulated—when a heat exchanger segment is provided which can be individually regulated in an advantageous manner. 
         [0042]    In conclusion,  FIG. 3   d  shows an air conditioning device  2  or  28  according to the invention between two electronic device cabinets  34 , wherein cold air from radial fans impacts the area in the direction along the front sides  36  and is applied based on Coanda effect to the front sides. 
         [0043]    The embodiments of the air conditioning devices according to the invention are particularly effective based on the Coanda effect of radially conducted cooling air. It should be pointed out in this context that the air conditioning devices according to the invention are not limited to indicated embodiments since every conceivable variation of the technical realization having air supplying devices, which are arranged more or less next to or on top of one another and which are provided with different internal or external cooling devices, or designs of heat exchangers and flow mechanics details, also represent a subject of this invention.