Patent Publication Number: US-2011072835-A1

Title: Cooling device for electronic components

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to German application 202008003516.3 filed 12 Mar. 2008. 
     FIELD OF THE INVENTION 
     The invention concerns a refrigeration device for electronic components according to the preamble of the patent claim  1 . 
     BACKGROUND OF THE INVENTION 
     Such a refrigeration device is known from DE 10 2004 030 675 A1. There a refrigeration installation is described for electronic components that feature a mounting plate to which electronic components are attached in heat-conducting contact. To the mounting plate several heat exchanger elements are attached. The mounting plate forms thereby the back wall of a switch box and is covered by means of a cover so that a flow channel forms that is located outside the interior space of the switch box and to which external air is guided by means of a blower. In the interior space an additional air stream can be generated along the mounting plate by means of convection or an additional blower. 
     Furthermore it is proposed there to utilize special heat exchanger elements such as they are described in DE 102 33 736. 
     These known refrigeration installations work in principle with an air/air heat exchange, whereby one assumes that the exterior air is colder than the interior air in the interior space of the switch box. As is well known, the heat exchange in a heat exchanger depends very significantly on the temperature difference of the media that are in heat exchange with one another. As a result the cooling performance of the known installations is not satisfactory in the case of high external temperatures. 
     As part of prior art active refrigeration installations that work according to the principle of a refrigerator with a compressor or with a Peltier element (compare U.S. Pat. No. 5,706,668) are therefore also already known As an example DE 10 2006 034 487 A1 describes a heat exchanger with Peltier elements that are on both sides in a heat-exchanging contact with heat releasing and heat absorbing elements, whereby respectively a fluid heating and a fluid cooling channel abuts against the heat releasing and heat absorbing elements. 
     Refrigeration installations with Peltier elements are also described in DE 10 2006 020 502 and 10 2006 020 503, DE 10 2006 020 499, DE 299 21 448 U1, and DE 203 01 232 U1. 
     The DE 201 05 487 U1 describes a refrigeration device with Peltier elements whereby a switch-over between individual cooling modes is possible, depending on the surrounding temperature, due to the fact that the Peltier elements can be switched either all in parallel, or group-wise or as a whole in series, whereby the cooling performance is controllable by simple means. 
     The DE 200 07 920 U1 describes a blower apparatus for a housing with Peltier elements whereby the air stream can be reversed in a selectable manner in order to switch between cooling and heating operation. 
     Peltier elements are obtainable today as flat platelets with heat-releasing and heat-absorbing side. Of a disadvantage is of course their consumption electrical energy and the problem that the efficiency or the cooling performance is temperature-dependent and diminishes with increasing temperature difference between heat-absorbing side and heat-releasing side. 
     SUMMARY OF THE INVENTION 
     It is the purpose of the invention to improve the air conditioning device of the type referred to above insofar that it maintains the temperature of electronic components well within a prescribed temperature range over a large temperature range of the external temperature, that is features a high power density, is as compact as possible, and features a low consumption of electrical energy. 
     The problem is solved according to the characteristics indicated in patent claim  1 . Advantageous embodiments and improvements of the invention can be deduced from the sub-claims. 
     The basic principle of the invention is to implement the refrigeration device as a compact device with Peltier elements that are provided on both sides with heat-exchanger elements, whereby the device features two air intakes and two air exhausts that are connected with two separated flow paths, of which one runs along one side of the Peltier element and one runs along on the other side of the Peltier element. The two intakes lie preferably parallel in one plane, whereby with each intake a ventilator is associated that guides the entering air from a intake space across guiding plates to the corresponding air stream path on the upper or lower side of the Peltier element. 
     The device is preferably adapted to norm switch boxes with 19 inch tracks and features a height of only one height unit, corresponding to 44.45 mm, a width of 448 mm, and a depth of 480 mm. 
     The device can work as a pure circulation installation that draws in the cool external air through slits or openings of a switch box and circulates it in the interior space of the switch box. If increased cooling performance is required the Peltier element can be switched into active mode and work thereby as an active chiller. The Peltier element can contain, taking the measures described above into account, up to 27 individual elements that each feature a power of 10 to 15 Watt per unit so that a cooling power of 270 to 405 Watt is possible. 
     In the case of the circulation operation mentioned first one of the ventilators can also be turned off. 
     In summary, one therefore obtains a hybrid refrigeration device of low installation height and high power density. By means of the two operation modes the consumption of electrical energy can be economized. The device can be installed in different directions in a switch box so that the cooling air can be blown out upward or downward. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In what follows the invention is explained in more detail based on an embodiment example in connection with the drawing. It is shown: 
         FIG. 1 , a perspective representation of a partially cut switch box with a refrigeration device according to the invention; 
         FIG. 2 , a perspective, schematic representation of the refrigeration device according to the invention; 
         FIG. 3 , a schematic top view of an opened refrigeration device according to the invention; 
         FIG. 4 , a cut along the line A-A of  FIG. 3 ; and 
         FIG. 5 , a cut along the line B-B of  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIG. 1  presents a conventional switch box  1  (without door) that features lateral tracks  2  and  3  for the sliding-in and retaining of electrical and electronic components, as well as vertical carriers  4 ,  5 ,  6 , and  7 , to which external walls are attached, whereby two of the carriers, in this case carriers  4  and  6 , feature rows of boreholes  8  and  9  for the attachment of components to be slid in. On the carriers  6  and  7  corresponding rows of boreholes can also be provided. 
     The refrigeration device according to the invention is implemented as a slide-in element that is adapted to the dimensions of such norm switch box. It for example features the dimensions mentioned above if it is utilized in a 19 inch switch box. The refrigeration device in its entirety is labeled with the reference symbol  10 . By means of two lateral flaps  11  and  12  that feature holes  13  and  14  it can be attached at the carriers  4  and  6  and the rows of boreholes there, whereby it is held to the tracks  2  and  3 . 
     As can be discerned from  FIG. 2 , the refrigeration device features two intakes  15  and  16  that lie next to each other parallel in a plane and at which ventilators are disposed that are not represented, by means of which the external air is drawn into two separate chambers  19  and  20  corresponding to the arrows  17  and  18 , whereby the two chambers  19  and  20  are separated from each other by means of partition  21 . 
     Adjacent to the two chambers  19  and  20  is a Peltier plate disposed that contains a multitude of individual Peltier elements that are equipped on both sides with heat exchanger elements. The Peltier plate  22  is disposed in the middle of height H and divides in its area the refrigeration device into a first channel  23  and second channel  24 . The channel  23  is connected with the space  19 , whereby the guiding plate  25  in connection with the partition  21  assures that the air entering by means of the opening  15  enters only into the first channel  23 . In a corresponding manner the second space  20  is connected by means of a guiding plate  26  with the channel  24  so that air that is drawn in by means of the intake  16  streams only through the channel  24 . 
     The first channel  23  ends at an exhaust opening  27  facing the front while the second channel  24  ends at one or several exhaust openings  28  that are provided at an upper or lower side of the refrigeration device depending on the installation location. In other words the device can be installed in such a manner that the cooling air is blown out upward or downward. The exhaust opening  18  can extend over the entire breadth of the device. It can however also feature other dimensions and thereby blow cooling air better aimed and in a more concentrated manner at predetermined locations. 
     The exhaust  27  is aligned during installation in the refrigeration device in a switch box according to  FIG. 1  with an opening  29  in a back wall  30 , while the opening  28  of the second channel  24  is aligned toward the interior space of the switch box  1 . 
     The Peltier plate  22  features during active Peltier operation a hot side and a cold side. During active cooling operation the electrical voltage is applied to the Peltier elements in such a manner that the hot side points to channel  23  and the cold side to channel  24 . 
     The device can be operated, as mentioned, in two modes of operation. In the first mode of operation it works as pure air circulation. In so doing the ventilator at the intake  15  can be switched off and only the ventilator at intake  16  can be operated. Air is then drawn, corresponding to the arrows  18  at the intake  16 , into the chamber  20  and blown by means of the channel  24  to the exhaust  28 . In so doing external air is drawn in through slits and other openings of the switch box and blown by conventional means into the interior space where it can flow out through openings that are not represented. 
     If the temperature of the external air is so high that sufficient cooling cannot be attained, the Peltier plate  22  or its Peltier elements are switched to active mode and the ventilator at the intake  15  is switched on. The air drawn in by means of the intake  16  passes corresponding to the arrows  18  across the actively cooled side of the Peltier plate  22  in the channel  24  and is blown out at the exhaust  28 . The air drawn in by means of the intake  15  flows along the arrows  17  on the hot side of the Peltier plate  22  and discharges the heat there by means of the exhaust opening  27 , whereby this air is transported to the outside by means of the opening  29  on the backwall  30  of the switch box. 
       FIG. 3  shows a plan view of the partially opened refrigeration device, whereby here also the ventilators have been left off. One recognizes the two openings  15  and  16  to the chambers  19  and  29 , the partition  21  that separates the two chambers  19  and  20 , and the guiding plates  25  and  26  that guide the respective air streams  17  and  18  (compare  FIGS. 4 and 5 ) onto the two sides of the Peltier plate  22 . One furthermore sees the exhaust opening  28  of the channel  24 . 
       FIG. 4  presents a cut along the line A-A that indicates more clearly how the air stream gets along the arrows  18  from the intake  16  by means of the first ventilator  32  into the chamber  20  and the guiding plate  26  into the channel  24  and from there to exhaust opening  28 . Correspondingly  FIG. 5  shows in a cut along the line B-B the air stream along the arrows  17 , by means of the intake  15 , a second ventilator  33 , the chamber  19  and the channel  23  to the exhaust opening  27  along the other side of the Peltier plate  22 .