Abstract:
A passively cooled computer includes two or more components arranged in a housing frame  41,  wherein each of these components is associated with a cooling body for dissipating waste heat of the component when the component is in operation. The cooling bodies each include a cooling surface, and these cooling surfaces are arranged to oppose one another with their cooling surfaces and thereby define an air channel leading vertically through the inside of the housing frame. The cooling bodies substantially separate the air channel from the remaining volume inside the housing frame.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The invention relates to electrical and electronic data processing devices, in particular to a passively cooled computer 
         [0002]    Such a computer is described in U.S. Pat. No. 7,095,611. The housing cover and floor of this computer are shaped as cooling elements. Internally, the computer is separated in an upper, hot compartment, and a lower, cooler compartment. Components with a larger heat loss, for example the processor, are arranged in the upper compartment. However, the temperature of the cooling elements can become uncomfortable, and the power that can be dissipated is limited. 
         [0003]    U.S. Pat. No. 5,671,120 shows a personal computer, in which one side of the housing is configured to be a cooling body cooling the processor. The other sides of the housing consist of perforated plates which allow for an air flow through the entire inner volume of the housing. The openings in the side walls allow for objects to fall in and damage the computer. 
         [0004]    U.S. Pat. No. 4,980,848 shows a laptop computer, in which components to be cooled are arranged behind the monitor and a gap in the monitor housing allows for the flow of air. The monitor housing comprises air entry openings at the bottom and exit openings at the top, allowing for heat to be transported away by convection. 
         [0005]    US 2006/198112 A1 shows a computer with three sections. A middle section comprises a hard disc with cooling ribs attached to its top. In another section, a set of vertically arranged cooling ribs for cooling circuits is arranged. The cooling ribs form an internal channel, and corresponding holes may be arranged in the top and bottom. A fan is optional. 
         [0006]    US 2004/156180 A1 describes a passively cooled computer with cooling ribs pointing outwards. In between the cooling ribs, among others, a motherboard is arranged, with the processor being pressed against one of the cooling bodies by elastic elements. The hard disc is arranged between the cooling bodies and is separated from them by a flexible, vibration damping layer. 
         [0007]    The known solutions do not provide for sufficient dissipation of power for the various different components of the computer. Thus, the processing power of modern processors cannot be made use of. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    It is the object of the invention, to provide for a passively cooled computer without the disadvantages described. 
         [0009]    The passively cooled computer according to the invention has two or more components arranged in a housing frame, wherein each of these components is associated with a separate cooling body for transporting away the waste heat of the component during operation of the computer. The cooling bodies each include a cooling surface, and the cooling bodies are arranged with these cooling surfaces opposing each other and defining at least one air channel leading vertically through the inside of the housing frame. 
         [0010]    This makes it possible to dissipate the entire waste heat of the computer without active cooling, that is, in particular, without fans, such that the long term operating temperature equilibrium inside the computer remains low and in a range that is tolerable for constant operation. The vertical channel leading through the entire housing causes a chimney effect transporting the cooling air through the channel. This chimney effect, as a rule occurs with a channel length of more than twenty centimeters (the term “vertical” is, throughout the entire application, used in relation to the computer in its operating position). 
         [0011]    The cooling bodies preferably substantially separate the air channel from the remaining volume inside the housing frame. This causes the cooling air to come into contact with only the cooling surfaces of the cooling bodies. Since a closed cooling channel is provided, that is, there are no air holes in the housing or in the cooling bodies, damage by parts falling into the computer is eliminated. 
         [0012]    In a preferred embodiment of the invention, the air channel comprises a lower air intake opening and an upper air outlet opening, and the air intake opening by the shape of the housing frame is distanced from a surface on which the computer is placed. In this manner the chimney between the cooling bodies is supplied with air. For this, preferably, the housing frame comprises a floor with an opening corresponding to the air intake opening of the air channel, and the floor is distanced by means of foot elements from a surface on which the computer is placed. 
         [0013]    This invention allows for dissipation of the waste heat of a computer of typical power passively, that is, without fans, and without having to substantially limit the power of the computer and its components, in particular the processor, mass storage, power supply etc. 
         [0014]    The housing frame preferably constitutes the carrying frame, on which the components or sub-units of the computer such as processor(s), volatile memory (RAM), mass storage devices such as hard discs, CD and/or DVD-drives, interface adapters, power supply and/or batteries are mounted. The housing frame preferably is made of thin sheet metal parts, preferably with a thickness of less than one millimeter. This improves the thermal decoupling of the sub-units having different temperatures. In order to further reduce thermal bridges between different housing sections, optional metallic cladding elements are arranged outside the housing frame, covering at least one side surface of the housing frame, and being distanced from the housing frame by an air gap. 
         [0015]    At the top of the housing, a cladding that is permeable by air can be arranged, exhibiting (seen in a horizontal direction) a round or convex cross section. This prevents users from depositing objects on the housing and thereby obstructing the air channel. 
         [0016]    As a result, different sections of the computer exhibit different temperatures adapted to the temperature operating ranges of the components. “Hot” subunits such as the processor unit are thereby separated from “cold” subunits such as hard disks and further from power units such as the power supply. 
         [0017]    In a preferred embodiment of the invention, at least one mass storage device, in particular a hard disk drive, is thermally coupled to a mass storage device cooling body for dissipating the waste heat of the mass storage device. This cooling body is one of the cooling bodies defining the air channel. Consequently, this unit is passively cooled as well. 
         [0018]    Preferably, the at least one mass storage device is flexibly suspended together with its mass storage device cooling body. That is, the mass storage unit is rigidly coupled to the associated cooling body. By means of the flexible suspension on the one hand the cooling body is thermally separated from the other cooling bodies, on the other hand, vibrations of the mass storage unit—typically a hard disk drive—are separated from the remaining structure. Thus, hardly any vibrations are transmitted to the housing, resulting in a virtually noiseless operation of the computer. 
         [0019]    Preferably, this suspension is done by means of flexible elements, suspending the mass storage unit and its cooling body from an opposing cooling body, which, with the mass storage unit cooling body, forms the air channel. The mass storage unit and its cooling body are preferably suspended from the opposing cooling body alone, i.e. they are not suspended from any other elements of the computer or its housing, and are free to move or vibrate with respect to such other elements. 
         [0020]    In a further preferred embodiment of the invention, at least one processor unit and one power supply are thermally coupled each to a dedicated, associated cooling body. These dedicated cooling bodies are preferably thermally separated from one another, that is, they do not touch, or are at least made of separate pieces. 
         [0021]    The abovementioned cooling bodies preferably extend in a plane and are arranged with this plane in a vertical orientation. They preferably comprise cooling ribs which in particular run in a vertical direction. In this manner, a chimney or a plurality of partial chimneys can be formed between the vertical cooling ribs of two cooling bodies that are arranged with the cooling ribs opposing one another. 
         [0022]    In a further preferred embodiment of the invention, an insulation layer is arranged between at least one pair of cooling bodies that oppose one another. Thus, this layer extends in parallel and in-between the cooling bodies and extends substantially over the entire opposing surfaces of the two cooling bodies. In this manner the cooling bodies are decoupled from one another with respect to infrared radiation, and almost not heat exchange between the cooling bodies will take place. This allows arrangement of components and cooling bodies with different temperatures opposite one another without the hotter cooling body heating up the cooler one. 
         [0023]    Further preferred embodiments of the invention correspond to the dependent claims. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0024]    The subject matter of the invention will be explained in more detail in the following text with reference to preferred exemplary embodiments which are illustrated in the attached drawings, in which: 
           [0025]      FIG. 1-4  are partially cut open views of a passively cooled computer; 
           [0026]      FIG. 5  is an arrangement of cooling bodies forming an air channel; 
           [0027]      FIG. 6  is an exploded view of this arrangement; 
           [0028]      FIG. 7  is a sectional view of this arrangement; 
           [0029]      FIG. 8  is a detail from the area Z of figure rubber element rubber element  7 ; and 
           [0030]      FIG. 9  is a cross section of a detail from part of a housing cladding. 
       
    
    
       [0031]    The reference symbols used in the drawings, and their meanings, are listed in summary form in the list of reference numbers. In principle, identical parts are provided with the same reference numbers in the figures. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0032]    The main elements of a computer cooled according to the invention are shown in  FIGS. 1 to 4 . The computer is shown in its operating condition, that is, with vertically oriented cooling channels. The main elements of the cooling arrangement alone are shown in  FIGS. 5 to 7 . 
         [0033]    The computer  10  comprises several subunits  1 ,  2 ,  3  which are arranged in a housing  4  with a load carrying housing frame  41 : 
         [0034]    A processor unit  1  with one or more processors  12  and further elements typically arranged on a motherboard of a computer. The processor  12  and optionally also some of the further elements are thermally coupled to a processor cooling body  11 , for example by mechanically pressing them against one another, with a thermally conductive material placed in-between for bridging gaps. The processor cooling body  11  is, in a border area, attached to the housing frame  41 . 
         [0035]    A hard disk unit  2  with one or more hard disks  22 . The hard disk unit(s)  2  are thermally coupled to a hard disk cooling body  21 . The hard disk cooling body  21  is mounted to the opposing processor cooling body  11  by means of a flexible suspension made of distance bolts  6  and rubber elements  7 . This can be seen in more detail in  FIGS. 6 ,  7  and  8 . 
         [0036]    A power supply unit  3  with a power supply  32 . The power supply  32  is thermally coupled to a power supply cooling body  31 . The power supply cooling body  31  is, in a boundary area, attached to the housing frame  41 . The power supply  32  itself is configured for passive cooling. 
         [0037]    The cooling bodies  11 ,  21 ,  31  are substantially planar and each comprise, on cooling surfaces  13 ,  23 ,  33  which are opposite to the components to be cooled, cooling ribs  8 . The cooling surfaces  13 ,  23 ,  33  are arranged substantially vertical (when the computer is in its operating position or condition), with the cooling ribs  8  also running in a vertical direction. 
         [0038]    The cooling bodies  11 ,  21 ,  31  with their cooling surfaces  13 ,  23 ,  33  define one or more air channels  9 . These also run in a vertical direction, corresponding to the orientation of the cooling surfaces  13 ,  23 ,  33  and the cooling ribs  8 , respectively. The air channels  9  are closed, by means of the cooling bodies  11 ,  21 ,  31 , with respect to the remaining volume inside the housing frame  41 . 
         [0039]    The air channels  9  at their common lower end form an air intake opening  91 , and at their common upper end form an air outlet opening  92 . Correspondingly, in the region of these openings there are arranged openings of the housing frame  41 . Below the air intake opening  91  the air is guided in sideways by means of the air intake opening  91  being elevated with respect to the surface on which the computer  10  is standing. This is accomplished, for example, by raising the housing frame  41  by feet  43 . Alternatively, the housing frame  41  comprises lateral air intake openings at its sides, and a hollow space leading from these lateral air intake openings to the air intake opening  91 . 
         [0040]    Preferably, a cladding with topside and/or lateral air outlet openings is arranged above the air outlet opening  92 . The cladding can be bent in a convex shape or be inclined, to prevent the air outlet from being obstructed by objects placed on the computer. 
         [0041]    In the embodiment of the invention shown, the hard disk cooling body  21  and the power supply cooling body  31  are separated, that is, they are made of separate pieces, and they are arranged with their cooling surfaces  23 ,  33  opposing the cooling surface  13  of the processor cooling body  11 . Preferably, insulation  5  is arranged between the cooling surfaces opposing one another, in order to prevent a heat exchange by radiation. This insulation  5  consists, for example, of a synthetic heat resistant material with a thickness of around ca. one millimeter. 
         [0042]    The housing frame  41  can be covered with external cladding elements, for example by a housing cladding  42 . This covers at least one lateral surface of the computer  10 . For esthetic or stability reasons it may be desirable to have the housing cladding  42  made of metal. In this case, in order to prevent a heat transfer from one side to the other (i.e. from the hot to the cool side), such a housing cladding  42  is not simply screwed flat onto the housing frame  41 , but rather comprises a cutout  44  and/or is distanced from the housing frame  41  by means of distance elements  45 , such that an insulating layer of air is created between the housing frame  41  and the housing cladding  42 . 
         [0043]    The end plate of the housing cladding  42  shown in the figures thus comprises, on the one hand, feet  43  for raising the housing frame  41 , and on the other hand a cutout  44  on the inside.  FIG. 9  shows a horizontal sectional view through an endplate and the adjoining region of the housing frame  41 . The load carrying housing frame  41  made of thin sheet metal does not form a substantial bridge transferring heat from the hotter part with the processor unit  1  and the processor cooling body  11  into the cooler part of the power supply unit  3  with the power supply cooling body  31 . In order to prevent this heat transfer from taking place through the housing cladding  42 , the housing cladding  42  is separated from the housing frame  41  by the air gap created by the cutout  44 . 
         [0044]      FIG. 4  shows a motherboard  14  which is arranged in parallel with the processor cooling body  11  and carries further electronic components of the computer  10 . The processor  12  by means of its connectors is attached to the motherboard  14 . In another preferred embodiment of the invention, the processor is attached to the motherboard  14 , and the block designated with reference number  12  is a cooling block that is pressed against the processor and conducts the heat of the processor to the processor cooling body  11 . 
         [0045]    In  FIG. 4  a plug-in card carrier  46  is shown. It comprises a vertically arranged card carrier which can be pulled out of the computer  10  by means of a handle  50 . In an inserted state, the card carrier is plugged in a slot connector  49  of the computer  10  by means of a carrier connector  47 . The card carrier comprises an adapter connector  48  into which an extension card (not shown) can be plugged in, whereby the extension card is also arranged vertically. In this manner, the extension card can also be passively cooled by a vertical air current. 
         [0046]    By combining the different measures described, it is made possible, for example, to keep the temperature difference between different subunits significantly high, also in the stationary condition, after several hours of operation. For example, the temperature of the processor unit may be 70° C., and the temperature of the hard disk unit 35° C. The vertical cooling bodies  11 ,  21 ,  31  and air channel(s)  9  thus divide the inside of the computer  10  in a warmer part, comprising components with a relatively high power loss, on one side of the air channel(s)  9  and a cooler part, comprising components with a relatively low power loss, on the opposite side of the air channel(s)  9 . 
         [0047]    In an exemplary computer according to the invention, it is possible to dissipate a maximal power of ca. 150 W. For this, ca. 4 kg of aluminum are used for the cooling bodies. The outer dimensions of the housing frame  41  are about 40 cm (height) by 40 cm (depth) by 18 cm (width). 
       LIST OF REFERENCE NUMBERS 
       [0000]    
       
           1  processor unit 
           11  processor cooling body 
           12  processor 
           13  cooling surface 
           14  motherboard 
           2  hard disk unit 
           21  hard disk cooling body 
           22  hard disk 
           23  cooling surface 
           3  power supply unit 
           31  power supply cooling body 
           32  power supply 
           33  cooling surface 
           4  housing 
           41  housing frame 
           42  housing cladding 
           43  feet 
           44  cutout 
           45  distance element 
           46  plug-in card carrier 
           47  carrier connector 
           48  adapter connector 
           49  slot connector 
           50  handle 
           5  insulation 
           6  distance bolt 
           7  rubber element 
           8  cooling rib 
           9  air channel 
           91  air intake opening 
           92  air outlet opening 
           10  computer