Abstract:
A storage unit includes: a storage section containing an information processing apparatus; an intake section allowing intake of a cooling medium into the information processing apparatus for cooling the information processing apparatus; a discharge section receiving the cooling medium discharged from the information processing apparatus; a cooling medium flow generating section configured to control intake and discharge of the cooling medium; a partition section isolating the intake section and the discharge section from each other; an aperture formed in the partition section; a detector section configured to detect an inflow of the cooling medium, discharged from the discharge section, through the aperture; and a controller section configured to control the cooling medium flow generating section in accordance with a result of the detection of the detector section.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2008-148637, filed on Jun. 5, 2008, the entire contents of which are incorporated herein by reference. 
     FIELD 
     The embodiments discussed herein are related to a storage unit for enclosing an information processing apparatus. 
     BACKGROUND 
     Some information processing apparatuses include a rack placed in a storage section, namely a box-shaped enclosure. A server computer or computers of a rack mount type is mounted on the rack, for example. An airflow generator is enclosed in the enclosure of the server computer to generate airflow across the interior space of the enclosure of the server computer. 
     The airflow generator operates in the box-shaped enclosure. It is required to supply a sufficient amount of air to the airflow generator. In general, a ventilation fan is utilized to supply air. An information processing apparatus includes an arbitrary number of a server computer or computers enclosed in the box-shaped enclosure. It is thus desired to introduce an appropriate amount of air into the box-shaped enclosure in accordance with the number of the mounted server computer. 
     SUMMARY 
     According to an aspect of the invention, a storage unit includes: a storage section containing an information processing apparatus; an intake section allowing intake of a cooling medium into the information processing apparatus for cooling the information processing apparatus; a discharge section receiving the cooling medium discharged from the information processing apparatus; a cooling medium flow generating section configured to control intake and discharge of the cooling medium; a partition section isolating the intake section and the discharge section from each other; an aperture formed in the partition section; a detector section configured to detect an inflow of the cooling medium, discharged from the discharge section, through the aperture; and a controller section configured to control the cooling medium flow generating section in accordance with a result of the detection of the detector section. 
     The object and advantages of the embodiment will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the embodiment, as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front perspective view of schematically illustrating a storage box, for an information processing apparatus, as a storage unit according to a first embodiment of the present invention; 
         FIG. 2  is a rear perspective view schematically illustrating the storage box; 
         FIG. 3  is a front perspective view schematically illustrating the storage box with a first door opened; 
         FIG. 4  is a front view schematically illustrating the storage box with the first door opened; 
         FIG. 5  is a rear perspective view schematically illustrating the storage box with a second door opened; 
         FIG. 6  is an exploded view schematically illustrating a storage space, a first auxiliary space and a second auxiliary space; 
         FIG. 7  is a sectional view schematically illustrating the inner structure of the storage box according to the first embodiment of the present invention; 
         FIG. 8  is an enlarged partial sectional view schematically illustrating a packing member according to an example; 
         FIG. 9  is a block diagram showing a control system; 
         FIG. 10  is a front perspective view schematically illustrating the storage box with an information processing apparatus mounted therein; 
         FIG. 11  is a sectional view schematically illustrating airflow generated in the storage box during operation; 
         FIG. 12  is a sectional view schematically illustrating airflow generated in the storage box during operation; 
         FIG. 13  is a sectional view schematically illustrating airflow generated in the storage box during operation; 
         FIG. 14  is an enlarged front view schematically illustrating an anemoscope according to an example; 
         FIG. 15  is a schematic view schematically illustrating a server room as a storage unit according to a second embodiment of the present invention; 
         FIG. 16  is a schematic view schematically illustrating airflow generated in the server room during the operation of an information processing apparatus; and 
         FIG. 17  is a schematic view schematically illustrating airflow generated in the server room during the operation of an information processing apparatus. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments of the invention will be explained below with reference to the accompanying drawings. 
       FIG. 1  schematically illustrates a storage box  11 , for an information processing apparatus, as a storage unit according to a first embodiment of the present invention. The storage box  11  includes a box-shaped enclosure  12 . A first door  14  is configured to close a first plane, namely a front surface  13  of the box-shaped enclosure  12 . A second door  16  is likewise configured to close a second plane, namely a back surface  15  of the box-shaped enclosure  12 . The first door  14  and the second door  16  are coupled to the box-shaped enclosure  12  for relative swinging movement, namely for opening and closing operations. Hinges  17  may be utilized to couple the first and second doors  14 ,  16 , for example. The first door  14  and the second door  16  are respectively allowed to swing around the hinge pins of the hinges  17 . The hinges  17  accept the attachment and detachment of the first door  14  and the second door  16  to and from the box-shaped enclosure  12 . Latches  18  in combination with the hinges  17  serve to make the first door  14  and the second door  16  tightly contact with the box-shaped enclosure  12 . The latches  18  prevent the first door  14  and the second door  16  from opening. Deadening walls are employed to form the box-shaped enclosure  12 , the first door  14  and the second door  16 . 
     The first door  14  includes a first auxiliary box-shaped enclosure  21 . The first auxiliary box-shaped enclosure  21  includes a first outer wall member  21   a  extending in parallel with the front surface  13  of the box-shaped enclosure  12 . Second and third outer wall members  21   b ,  21   c  are connected to the side edges of the first outer wall member  21   a , respectively. The second and third outer wall members  21   b ,  21   c  are opposed to each other. Fourth outer wall members  21   d ,  21   d  are connected to the upper and lower edges of the first outer wall member  21   a , respectively. The fourth outer wall members  21   d ,  21   d  are opposed to each other. As described later, the first outer wall member  21   a , the second outer wall member  21   b , the third outer wall member  21   c  and the fourth outer wall members  21   d ,  21   d  are combined together to define an auxiliary space in the form of a parallelepiped. A first ventilation opening  22  is formed in the first outer wall member  21   a . The first ventilation opening  22  is a window opening elongated in the direction of gravity. The first ventilation opening  22  extends along the edge defined between the first outer wall member  21   a  and the third outer wall member  21   c.    
     As depicted in  FIG. 2 , the second door  16  includes a second auxiliary box-shaped enclosure  23 . The second auxiliary box-shaped enclosure  23  includes a first outer wall member  23   a  extending in parallel with the back surface  15  of the box-shaped enclosure  12 . Second and third outer wall members  23   b ,  23   c  are connected to the side edges of the first outer wall member  23   a , respectively. The second and third outer wall members  23   b ,  23   c  are opposed to each other. Fourth outer wall members  23   d ,  23   d  are connected to the upper and lower edges of the first outer wall member  23   a , respectively. The fourth outer wall members  23   d ,  23   d  are opposed to each other. As described later, the first outer wall member  23   a , the second outer wall member  23   b , the third outer wall member  23   c  and the fourth outer wall members  23   d ,  23   d  are combined together to define an auxiliary space in the form of a parallelepiped. A second ventilation opening  24  is formed in the first outer wall member  23   a . The second ventilation opening  24  is a window opening elongated in the direction of gravity. The second ventilation opening  24  extends along the edge defined between the first outer wall member  23   a  and the third outer wall member  23   c.    
     A power supply cord  25  is connected to the side surface of the box-shaped enclosure  12 . The power supply cord  25  is connected to an outlet, for example. Electric power is supplied to the box-shaped enclosure  12  through the power supply cord  25 . 
     As depicted in  FIG. 3 , the first door  14  includes a first deadening wall member  26 . The first deadening wall member  26  closes the front surface  13  of the box-shaped enclosure  12 . The outer periphery of the first deadening wall member  26  is connected to the second outer wall member  21   b , the third outer wall member  21   c  and the fourth outer wall members  21   d . When the first door  14  is closed, the first deadening wall member  26  extends along the front surface  13  of the box-shaped enclosure  12 . A packing member  27  is attached to the first deadening wall member  26  without a gap along the outer periphery of the first deadening wall member  26 . The packing member  27  may be made of rubber, for example. The packing member  27  will be described later in detail. 
     A first through opening  28  is formed in the first deadening wall member  26 . The first through opening  28  is a window opening elongated in the direction of gravity. The first through opening  28  extends along the edge defined between the first deadening wall member  26  and the second outer wall member  21   b . A first ventilating unit  29  is mounted in the first through opening  28 . The first ventilating unit  29  includes eight first ventilators  31 , for example. The individual first ventilator  31  may be an axial flow fan unit, for example. The axial flow fan unit allows blades to rotate around a rotation axis extending in the horizontal direction. The axial flow fan unit generates horizontal airflow. The individual first ventilator  31  is fixed to the first deadening wall member  26 . The individual first ventilator  31  is separately removable from the first deadening wall member  26 . The first ventilating unit  29  has a performance to generate a predetermined amount of airflow. The first ventilators  31  may be arranged in the direction of gravity, for example. 
     A storage space  32  in the form of a parallelepiped is defined within the box-shaped enclosure  12  between the front surface  13  and the back surface  15 , for example. The box-shaped enclosure  12  opens at the front surface  13  and the back surface  15 , for example. A rack  33  is placed within the storage space  32 . The rack  33  is constructed as a so-called 19-inch rack. The rack  33  is designed to define a rack space for enclosing an information processing apparatus. The information processing apparatus will be described later. 
     A controller box  34  is placed on the bottom plate of the box-shaped enclosure  12 . A controller board is incorporated in the controller box  34  for controlling the operation of the first ventilators  31 , for example. The controller board will be described later in detail. 
     As depicted in  FIG. 4 , partition boards  35  are placed within the box-shaped enclosure  12 . The partition boards  35  serve to close a gap between the rack  33  and the box-shaped enclosure  12 . The partition boards  35  define the intake surface of a ventilation duct. The partition boards  35  and the box-shaped enclosure  12  in combination serve to form a ventilation duct. The discharge surface of the ventilation duct corresponds to the back surface  15  of the box-shaped enclosure  12 . The partition boards  35  define the entrance of the rack space, namely an air inlet  36 , in the intake surface of the ventilation duct. 
     Apertures  37  are formed in the individual partition board  35 . The apertures  37  may appropriately be arranged in accordance with the temperature distribution within the ventilation duct. Here, the apertures  37  are placed at three spots on each of the right and left sides of the rack  33 . The storage space  32  of the box-shaped enclosure  12  is equally divided into three space segments in the vertical direction, namely in the direction of gravity, for example. Specifically, the heights of the space segments are set equal. The apertures  37  are placed in the corresponding space segments, respectively, at the middle position equally distanced from the upper and lower surfaces of the individual space segment. The apertures  37  allow the intake and discharge of airflow for the ventilation duct. A first thermal sensor  38  is placed in the individual aperture  37 . The first thermal sensor  38  is configured to detect the temperature of airflow passing through the corresponding aperture  37 . 
     As depicted in  FIG. 5 , the second door  16  includes a second deadening wall member  39 . The second deadening wall member  39  closes the back surface  15  of the box-shaped enclosure  12 . The outer periphery of the second deadening wall member  39  is connected to the second outer wall member  23   b , the third outer wall member  23   c  and the fourth outer wall members  23   d . When the second door  16  is closed, the second deadening wall member  39  extends along the back surface  15  of the box-shaped enclosure  12 . A packing member  40  is attached to the second deadening wall member  39  without a gap along the outer periphery of the second deadening wall member  39 . The packing member  40  may be made of rubber, for example. 
     A second through opening  41  is formed in the second deadening wall member  39 . The second through opening  41  is a window opening elongated in the direction of gravity. The second through opening  41  extends along the edge defined between the second deadening wall member  39  and the second outer wall member  23   b . A second ventilating unit  42  is mounted in the second through opening  41 . The second ventilating unit  42  includes eight second ventilators  43 , for example. The individual second ventilator  43  may be an axial flow fan unit, for example. The axial flow fan unit allows blades to rotate around a rotation axis extending in the horizontal direction. The axial flow fan unit generates horizontal airflow. The individual second ventilator  43  is fixed to the second deadening wall member  39 . The individual second ventilator  43  is separately removable from the second deadening wall member  39 . The second ventilators  43  may be arranged in the direction of gravity, for example. The second ventilating unit  42  includes a set of ventilators identical to a set of ventilators incorporated in the first ventilating unit  29 . The second ventilating unit  42  thus has a performance equivalent to that of the first ventilating unit  29 . 
     Second thermal sensors  44  are placed in the ventilation duct. The second thermal sensors  44  are attached to a support post  45 , extending in the direction of gravity, at predetermined intervals, for example. The support post  45  is placed between the second deadening wall member  39  and the interior space of the rack  33 . Specifically, the support post  45  is placed outside the interior space of the rack  33  at a position distanced from the second deadening wall member  39 . The second thermal sensors  44  are arranged along the edge defined between the second deadening wall member  39  and the third outer wall member  23   c . The second thermal sensors  44  are designed to detect the ambient temperature. 
     As depicted in  FIG. 6 , the first auxiliary box-shaped enclosure  21  of the first door  14  defines a first auxiliary space  47  in the form of a parallelepiped. The first deadening wall member  26  serves to isolate the first auxiliary space  47  from the storage space  32 . The first auxiliary space  47  has a cross-section elongated in the direction of gravity. The first auxiliary space  47  is spatially connected to the storage space  32  through the first through opening  28 . The first auxiliary space  47  is spatially connected to the outer space through the first ventilation opening  22 . The first ventilation opening  22  is formed on the first auxiliary box-shaped enclosure  21  at a position opposed to the first deadening wall member  26  off the first through opening  28 . Specifically, the position of the first ventilation opening  22  is shifted from the position of the first through opening  28 . 
     Likewise, the second auxiliary box-shaped enclosure  23  of the second door  16  defines a second auxiliary space  48  in the form of a parallelepiped. The second deadening wall member  39  serves to isolate the second auxiliary space  48  from the storage space  32 . The second auxiliary space  48  has a cross-section elongated in the direction of gravity. The second auxiliary space  48  is spatially connected to the storage space  32  through the second through opening  41 . The second auxiliary space  48  is spatially connected to the outer space through the second ventilation opening  24 . The second ventilation opening  24  is formed in the second auxiliary box-shaped enclosure  23  at a position opposed to the second deadening wall member  39  off the second through opening  41 . Specifically, the position of the second ventilation opening  24  is shifted from the position of the second through opening  41 . 
     A third thermal sensor  49  is set in the first auxiliary space  47 . The third thermal sensor  49  is attached to the third outer wall member  21   c  of the first auxiliary box-shaped enclosure  21 . The third thermal sensor  49  is designed to detect the ambient temperature. 
     As depicted in  FIG. 7 , the box-shaped enclosure  12 , the first auxiliary box-shaped enclosure  21 , the first deadening wall member  26 , the second auxiliary box-shaped enclosure  23  and the second deadening wall member  39  are made of a deadening panel or panels or sound insulating material. The sound insulating material allows insulation of sound. A steel plate of a considerable thickness may be employed as the sound insulating material, for example. An increased thickness of the steel plate results in an enhanced rigidity of the steel plate. The enhanced rigidity enables a higher performance of insulation. An acoustic material  51  of a predetermined thickness is attached to the inner surface of the box-shaped enclosure  12 , the inner surface of the first auxiliary box-shaped enclosure  21 , the front and back surfaces of the first deadening wall member  26 , the inner surface of the second auxiliary box-shaped enclosure  23 , and the front and back surfaces of the second deadening wall member  39 . The acoustic material  51  is capable of absorbing sound. A urethane resin, a glass wool, a rock wool, a nonwoven fabric, or the like, may be employed as the acoustic material  51 . 
     The first auxiliary space  47  extends from the first through opening  28  to the first ventilation opening  22 . The first auxiliary space  47  bends between the first through opening  28  and the first ventilation opening  22 . The first ventilation opening  22  is formed on the first auxiliary box-shaped enclosure  21  at a position farthest from the first through opening  28 . A distance between the first ventilation opening  22  and the first through opening  28  may be set at 0.25 [m] or larger. Likewise, the second auxiliary space  48  extends from the second through opening  41  to the second ventilation opening  24 . The second auxiliary space  48  bends between the second through opening  41  and the second ventilation opening  24 . The second ventilation opening  24  is formed on the second auxiliary box-shaped enclosure  23  at a position farthest from the second through opening  41 . A distance between the second ventilation opening  24  and the second through opening  41  may be set at 0.25 [m] or larger. A flow passage for airflow is established in the storage box  11  based on the first ventilation opening  22 , the first auxiliary space  47 , the first through opening  28 , the storage space  32 , the second through opening  41  and the second ventilation opening  24 . 
     As depicted in  FIG. 8 , the packing member  27  includes a first elastic packing  52  and a second elastic packing  53 , both attached to the first door  14  to surround the storage space  32 . The second elastic packing  53  is attached to the first door  14  outside the first elastic packing  52 . Alternatively, both of the first elastic packing  52  and the second elastic packing  53  may be attached to the box-shaped enclosure  12 . Likewise, one of the first elastic packing  52  and the second elastic packing  53  may be attached to the first door  14  while the other of the first elastic packing  52  and the second elastic packing  53  is attached to the box-shaped enclosure  12 . It should be noted that the packing member  40  has the structure identical to that of the packing member  27 . 
     When the first door  14  or the second door  16  is closed, the first elastic packing  52  and the second elastic packing  53  are interposed between the box-shaped enclosure  12  and the first door  14  or the second door  16 . The first elastic packing  52  and the second elastic packing  53  are tightly held to elastically deform between the box-shaped enclosure  12  and the first door  14  or the second door  16 . The first elastic packing  52  and the second elastic packing  53  in this manner serve to eliminate a gap or gaps between the box-shaped enclosure  12  and the first door  14  or the second door  16  around the storage space  32  over the entire length. 
       FIG. 9  illustrates a control system according to an example of the present invention. The controller board  61  is incorporated in the controller box  34  as described above. A controller circuit, namely a microcomputer  62 , is mounted on the controller board  61 . The microcomputer  62  is configured to execute processing based on a program stored in an embedded memory. The microcomputer  62  reads out required data out of the embedded memory when the microcomputer  62  executes processing. 
     A first driver circuit  63  is mounted on the controller board  61 . The first driver circuit  63  is connected to the individual first ventilators  31 . The first driver circuit  63  is configured to control the on/off of the individual first ventilators  31  and the revolution speed of the individual first ventilators  31  in accordance with the instructions from the microcomputer  62 . Voltage is applied to the individual first ventilators  31  from the first driver circuit  63  to control the on/off and the revolution speed. The first ventilators  31  are allowed to perform to establish an equalized flow rate of the airflow based on the control, for example. The microcomputer  62  is capable of monitoring the status of the individual first ventilators  31  based on the operation of the first driver circuit  63 . 
     A second driver circuit  64  is likewise mounted on the controller board  61 . The second driver circuit  64  is connected to the individual second ventilators  43 . The second driver circuit  64  is configured to control the on/off of the individual second ventilators  43  and the revolution speed of the individual second ventilators  43  in accordance with the instructions from the microcomputer  62 . Voltage is applied to the individual second ventilators  43  from the second driver circuit  64  to control the on/off and the revolution speed. The second ventilators  43  are allowed to perform to establish an equalized flow rate of the airflow based on the control, for example. The microcomputer  62  is capable of monitoring the status of the individual second ventilators  43  based on the operation of the second driver circuit  64 . 
     The aforementioned first, second and third thermal sensors  38 ,  44 ,  49  are connected to the microcomputer  62 . The individual thermal sensors  38 ,  44 ,  49  are configured to output a sensor signal to the microcomputer  62 . The sensor signal serves to represent the temperature information specifying a temperature detected at the individual thermal sensor  38 ,  44 ,  49 . The microcomputer  62  in this manner obtains the temperature information for the individual thermal sensors  38 ,  44 ,  49 . An analog switch  65  is interposed between the microcomputer  62  and the first to third thermal sensors  38 ,  44 ,  49  for the collection of the temperature information. The analog switch  65  is utilized to connect the microcomputer  62  to the thermal sensors  38 ,  44 ,  49  in order. The sensor signals of the thermal sensors  38 ,  44 ,  49  are in this manner distinguished from one another. 
     A first door switch  66  and a second door switch  67  are connected to the microcomputer  62 . The first door switch  66  is placed between the box-shaped enclosure  12  and the first door  14 , for example. The first door switch  66  is configured to detect the opening of the first door  14 . The first door switch  66  outputs a first detection signal to the microcomputer  62 . The first detection signal represents detection information specifying the opening of the first door  14 . The first door switch  66  may be a contact switch which allows electric connection when the first door  14  is closed. Likewise, the second door switch  67  is placed between the box-shaped enclosure  12  and the second door  16 , for example. The second door switch  67  is designed to detect the opening of the second door  16 . The second door switch  67  outputs a second detection signal to the microcomputer  62 . The second detection signal represents detection information specifying the opening of the second door  16 . The second door switch  67  may be a contact switch which allows electrical connection when the second door  16  is closed. 
     A first power source  68  is connected to the microcomputer  62 . The alternating voltage is supplied to the first power source  68 . The first power source  68  is configured to convert the alternating voltage to the direct voltage. A regulator  69  is interposed between the microcomputer  62  and the first power source  68 . The regulator  69  may be mounted on the controller board  61 , for example. The regulator  69  is configured to convert the direct voltage from the first power source  68  to the voltage of a predetermined voltage level. The voltage of a desired voltage level is in this manner applied to the microcomputer  62 . Likewise, a second power source  71  is connected to the first driver circuit  63  and the second driver circuit  64 . The alternating voltage is supplied to the second power source  71 . The second power source  71  is configured to convert the alternating voltage to the direct voltage. Voltage of a desired voltage level is in this manner applied to the first driver circuit  63  and the second driver circuit  64 . 
     A power switch  72  is connected to the first and second power sources  68 ,  71 . Electric power is supplied to the power switch  72  through the aforementioned power supply cord  25 . When the power switch  72  is opened, the first and second power sources  68 ,  71  stop receiving the electric power. When the power switch  72  is closed, the electric power is supplied to the first and second power sources  68 ,  71 . 
     An error monitoring circuit  73  is interposed between the microcomputer  62  and the regulator  69 . The error monitoring circuit  73  is designed to detect the voltage supplied from the regulator  69  to the microcomputer  62 . The error monitoring circuit  73  monitors the output signal from the microcomputer  62  for a predetermined period after the start of the supply of the voltage. If the error monitoring circuit  73  receives no output signal from the microcomputer  62  in the predetermined period, the error monitoring circuit  73  detects a malfunction of the microcomputer  62 . The microcomputer  62  is set to execute a predetermined initial operation. The initial operation forces the microcomputer  62  to output the aforementioned output signal to the error monitoring circuit  73  immediately after the microcomputer  62  starts receiving voltage. 
     A display device  74  is connected to the microcomputer  62  and the error monitoring circuit  73 . The display device  74  may be placed on the outer surface of the box-shaped enclosure  12  or the first door  14 , for example. The microcomputer  62  outputs a predetermined display signal based on the status of the aforementioned sensor signals, the status of the first and second driver circuits  63 ,  64 , and the first and second detection signals. A predetermined display is displayed on the display device  74  based on such a display signal. Likewise, the error monitoring circuit  73  outputs a predetermined display signal to the display device  74  in response to the detection of a malfunction of the microcomputer  62 . Here, alphanumeric characters may be displayed on the display device  74 . A specific meaning may be assigned to an alphanumeric string beforehand. The display device  74  serves to reliably notify the user of the status of the first and second ventilating units  29 ,  42 , for example. The user is allowed to reliably become aware of the status of the first and second ventilating units  29 ,  42 . 
     Now, as depicted in  FIG. 10 , assume that server computers  75  of a rack mount type as information processing apparatuses are mounted on the rack  33  within the storage box  11 , for example. The storage box  11  provides an information processing apparatus in response to the incorporation of the server computers  75  into the storage box  11 . The front panels of the server computers  75  close the air inlet  36 . The front panel of the individual server computer  75  serves to provide the inlet of the individual server computer  75  within the intake surface of the ventilation duct. The power cord of the individual server computer  75  is connected to the aforementioned power supply cord  25 , for example. Electric power is supplied to the server computers  75  through the power supply cord  25 . The first door  14  and the second door  16  are opened during the setting and connection of the server computers  75 . When the setting and connection have been completed, the first door  14  and second door  16  are closed. The latches  18  serve to urge the first door  14  and the second door  16  against the box-shaped enclosure  12 . The first elastic packing  52  and the second elastic packing  53  serve to eliminate a gap or gaps between the box-shaped enclosure  12  and the first door  14  and between the box-shaped enclosure  12  and the second door  16  around the storage space  32  over the entire length. 
     As depicted in  FIG. 11 , the individual server computers  75  are placed within the interior space  76  of the rack  33 . In this case, a predetermined space is maintained between the front panels of the server computers  75  and the first deadening wall member  26 . A front space  77  is thus formed between the interior space  76  and the first deadening wall member  26 . Likewise, a predetermined space is maintained between the rear panels of the server computers  75  and the second deadening wall member  39 . A rear space  78  is thus formed between the interior space  76  and the second deadening wall member  39 . The front panels of the server computers  75  and the partition boards  35  in combination define the ventilation duct  79  within the box-shaped enclosure  12 . The ventilation duct  79  contains the interior space  76  and the rear space  78 . The first ventilators  31  are thus placed at positions upstream of the intake surface of the ventilation duct  79 . The second ventilators  43  are placed at positions downstream of the discharge surface of the ventilation duct  79 . 
     A cooling fan  81  operates within the individual server computer  75  in accordance with the inner temperature of the server computer  75  during the operation of the server computer  75 . The cooling fan  81  serves as an airflow generator. As depicted in  FIG. 11 , the cooling fan  81  is configured to generate a horizontal airflow from the front space  77  to the rear space  78  within the enclosure of the server computer  75 . The airflow is directed from the intake surface toward the discharge surface. In this case, the cooling fan  81  makes sound or noise during the operation. The box-shaped enclosure  12  and the first and second deadening wall members  26 ,  39  serve to insulate the sound. Simultaneously, the acoustic material  51  absorbs the sound within the box-shaped enclosure  12  and the first and second deadening wall members  26 ,  39 . The sound leaks out only from the first through opening  28  and the second through opening  41 . The sound is then directed from the first and second auxiliary spaces  47 ,  48  toward the first and second ventilation openings  22 ,  24 . Since the acoustic material  51  surrounds the first and second auxiliary spaces  47 ,  48 , the sound is sufficiently absorbed within the first and second auxiliary spaces  47 ,  48 . In particular, the first and second auxiliary spaces  47 ,  48  are respectively configured to bend between the first and second through openings  28 ,  41  and the first and second ventilation openings  22 ,  24 . The sound leaking from the first and second through openings  28 ,  41  collides against the first outer wall members  21   a ,  23   a  of the first and second auxiliary box-shaped enclosures  21 ,  23 , namely the acoustic material  51 . The transmission of the sound is effectively suppressed in this manner. The leakage of the sound is thus minimized. Noise is reliably reduced. 
     When the power switch  72  is turned on, electric power is supplied from the first power source  68  to the microcomputer  62 . The microcomputer  62  receives a sensor signal output from the individual thermal sensor  38 ,  44 ,  49 . The microcomputer  62  calculates the average of the temperature of the first thermal sensors  38  based on the sensor signals. The microcomputer  62  compares the average of the temperature of the first thermal sensors  38  with the temperature of the third thermal sensor  49 . The microcomputer  62  operates to calculate a difference in temperature between the average of the temperature for the first thermal sensors  38  and the temperature for the third thermal sensor  49 . If the difference in temperature is equal to a first temperature (one degree, for example) or larger, but less than a second temperature (four degrees, for example), the microcomputer  62  maintains the rotation speeds of the first and second ventilators  31 ,  43 . If the difference in temperature is equal to the second temperature or larger, the microcomputer  62  operates to increase the rotation speed of the first and second ventilators  31 ,  43 . Here, the rotation speed of the first and second ventilators  31 ,  43  can be changed stepwise at ten different levels, for example. The microcomputer  62  operates to increase the rotation speed of the first and second ventilators  31 ,  43  every two levels. The microcomputer  62  changes voltages output from the first and second driver circuits  63 ,  64  so as to increase the rotation speed. If the difference in temperature is less than the first temperature, the microcomputer  62  operates to reduce the flow rate of airflow generated in the first and second ventilators  31 ,  42 . Here, the microcomputer  62  operates to reduce the rotation speed of the first and second ventilators  31 ,  43  every two levels. Simultaneously, the microcomputer  62  calculates the average of the temperature of the second thermal sensors  44 . The microcomputer  62  compares the average of the temperature of the second thermal sensors  44  with the temperature of the third thermal sensor  49 . If the difference in temperature is equal to a predetermined temperature (15 degrees, for example) or larger, the microcomputer  62  operates to maximize the rotation speed of the first and second ventilators  31 ,  43 . This results in the maximum amount of the supplied air into the ventilation duct  79 . The flow rate of the airflow of the first ventilating unit  29  is set equal to that of the second ventilating unit  42 . The first ventilators  31  may have a uniform flow rate of the airflow in the first ventilating unit  29 . Likewise, the second ventilators  43  may have a uniform flow rate of the airflow in the second ventilating unit  42 . The individual ventilators  31 ,  43  may receive electric power of an equal voltage value. It should be noted that the flow rate of the first ventilating unit  29  may be different from that of the second ventilating unit  42 . Different flow rates may be set for the individual ventilators  31 ,  43 . In any case, generation of swirl is preferably avoided in the storage space  32 . The generation of swirl leads to an increased noise. 
     Now, assume that “balance” is established between the required amount of air into the cooling fans  81  and the amount of the air supplied in response to the operation of the first ventilating unit  29  and the second ventilating unit  42 . In this case, the first thermal sensors  38  are simultaneously exposed to both the air in the front space  77  and the air in the ventilation duct  79 . The front space  77  is filled with the air of a temperature identical to that of the external air. The ventilation duct  79  is filled with the air heated with the generated heat of the server computers  75 . The temperature of the first thermal sensors  38  thus slightly rises from the temperature of the external air. The difference in temperature between the first thermal sensors  38  and the third thermal sensor  49  becomes the first temperature or larger, but smaller than the second temperature. The current rotation speed of the first and second ventilators  31 ,  43  is thus maintained. The cooling fans  81  are allowed to receive a sufficient amount of air without redundancy or shortage. Airflow of a sufficient flow rate passes through the individual server computer  75 . Here, the amount of the air supplied in response to the operation of the first ventilating unit  29  and the second ventilating unit  42  may be set slightly smaller than the required amount of the air into the cooling fans  81 . In this case, a slight amount of air leaks into the front space  77  from the ventilation duct  79  through the apertures  37 . This results in a rise in the temperature of the first temperature sensors  38 . However, since only a small amount of air leaks through the apertures  37 , the server computers  75  are allowed to receive air of a temperature almost equal to that of the external air. 
     Next, assume that the amount of the air supplied in response to the operation of the first ventilating unit  29  and the second ventilating unit  42  is insufficient for the required amount of air into the cooling fans  81 . In this case, air circulates within the box-shaped enclosure  12 . Specifically, as depicted in  FIG. 12 , air is introduced into the front space  77  from the ventilation duct  79  through the apertures  37 . The air heated with the generated heat of the server computers  75  passes through the apertures  37 . This results in a rise in the temperature of the first thermal sensors  38 . The difference in temperature between the first thermal sensors  38  and the third thermal sensor  49  becomes the second temperature or larger. The rotation speed of the first and second ventilators  31 ,  43  is thus increased. The cooling fans  81  are allowed to receive a sufficient amount of air without redundancy or shortage. Airflow of a sufficient flow rate passes through the individual server computer  75 . The server computers  75  are reliably cooled. 
     Assume that the amount of the air supplied in response to the operation of the first ventilating unit  29  and the second ventilating unit  42  is excessive for the required amount of air into the cooling fans  81 . In this case, the air overflows out of the front space  77 . Specifically, as depicted in  FIG. 13 , the air is thus introduced into the ventilation duct  79  from the front space  77  through the apertures  37 . The external air passes through the apertures  37 . This results in avoidance of a rise in the temperature of the first thermal sensors  38 . The difference in temperature is eliminated between the first thermal sensors  38  and the third thermal sensor  49 . The difference in temperature becomes smaller than the first temperature. The rotation speed of the first and second ventilators  31 ,  43  is thus reduced. This results in stoppage of the supply of the airflow at an excessive flow rate to the cooling fans  81 . Excessive power consumption is avoided at the first and second ventilating units  29 ,  42 . 
     The operation of the cooling fan  81  is controlled in response to the temperature inside the enclosure of the server computer  75 . The required amount of air into the cooling fan  81  depends on the temperature inside the enclosure. In addition, an arbitrary number of the server computers  75  can be contained in the box-shaped enclosure  12 . The amount of air to be supplied to all the cooling fans  81  depends on the number of the mounted server computers  75 . The aforementioned first and second ventilating units  29 ,  42  enable the supply of the required amount of air without redundancy or shortage. The individual server computer  75  is thus reliably cooled. The supply of an excessive amount of air is avoided. Unnecessary power consumption is avoided. 
     The external air is introduced into the first auxiliary space  47  through the first ventilation opening  22 . The air inside the first auxiliary space  47  is supplied to the front space  77  through the first through opening  28 . In this manner, the server computers  75  are allowed to always enjoy receiving the fresh external air. The air is discharged from the server computers  75  into the rear space  78 . The second ventilating unit  42  serves to supply the discharged air to the second auxiliary space  48 . The air is discharged through the second ventilation opening  24 . The air of a high temperature is in this manner discharged outside. The first and second ventilating units  29 ,  42  allow adequate ventilation inside the storage space  32 . An excessive increase in temperature is thus reliably avoided in the individual server computer  75 . The individual server computer  75  can effectively be cooled. Moreover, the first through opening  28  and the second through opening  41  is a window opening elongated in the direction of gravity. Since the server computers  75  are arranged in the direction of gravity in the rack  33 , the individual server computer  75  is allowed to equally enjoy the external air introduced through the first and second through openings  28 ,  41 . The individual server computer  75  can reliably be cooled. 
     The microcomputer  62  is configured to monitor the first door switch  66  and the second door switch  67  during the control on the operation of the first and second ventilating units  29 ,  42 . When the microcomputer  62  receives a first detection signal from the first door switch  66 , the microcomputer  62  outputs a control signal to the first driver circuit  63  to stop the operation of the first ventilating unit  29 . The operation of the first ventilating unit  29  is in this manner stopped when the first door  14  is opened. When the microcomputer  62  receives a second detection signal from the second door switch  67 , the microcomputer  62  outputs a control signal to the second driver circuit  64  to stop the operation of the second ventilating unit  42 . The operation of the second ventilating unit  42  is in this manner stopped when the second door  16  is opened. Alternatively, the microcomputer  62  may output a control signal to stop the operation of the first and second ventilating units  29 ,  42  in response to the reception of one of the first and second detection signals. 
     The first door  14  and the second door  16  are removably coupled to the box-shaped enclosure  12  in the storage box  11 . The first door  14  and the second door  16  are removed in a facilitated manner. The maintenance of the server computers  75  can be realized within the box-shaped enclosure  12  in a facilitated manner. The first door  14 , namely the first auxiliary box-shaped enclosure  21  and the first deadening wall member  26 , as well as the second door  16 , namely the second auxiliary box-shaped enclosure  23  and the second deadening wall member  39 , can be replaced in a facilitated manner. 
     The second ventilating unit  42  includes a ventilator set identical to a ventilator set incorporated in the first ventilating unit  29 . The opening area of the second through opening  41  is thus set equal to the opening area of the first through opening  28 . This results in minimization of the opening areas in the first and second deadening wall members  26 ,  39 . In addition, the performance of the second ventilating unit  42  is set equal to the performance of the first ventilating unit  29 . Slack of airflow can be avoided in the storage space  32 . No swirl is generated in the storage space  32 . 
     It should be noted that either one of the first ventilating unit  29  and the second ventilating unit  42  may be provided in the storage box  11  in the case where the mounted servers computer or computers  75  only requires a small amount of air. Even in such a case, the aforementioned phenomena occur. 
     Specifically, in the case where “balance” is established between the required amount of air into the cooling fans  81  and the amount of the air supplied in response to the operation of the first ventilating unit  29  or the second ventilating unit  41 , the temperature of the first thermal sensors  38  slightly rises from the temperature of the external air. The difference in temperature between the first thermal sensors  38  and the third thermal sensor  49  becomes the first temperature or larger, but smaller than the second temperature. The current rotation speed of the first ventilators  31  or the second ventilators  43  is thus maintained. The cooling fans  81  are allowed to receive a sufficient amount of air without redundancy or shortage. Airflow of a sufficient flow rate passes through the individual server computer  75 . 
     Next, assume that the amount of air supplied in response to the operation of the first ventilating unit  29  or the second ventilating unit  41  is insufficient for the required amount of air into the cooling fans  81 . In this case, airflow circulates within the box-shaped enclosure  12 . Specifically, air is introduced into the front space  77  from the ventilation dud  79  through the apertures  37 . The air heated with the generated heat of the server computers  75  passes through the apertures  37 . This results in a rise in the temperature of the first thermal sensors  38 . The difference in temperature between the first thermal sensors  38  and the third thermal sensor  49  becomes the second temperature or larger. The rotation speed of the first ventilators  31  or the second ventilators  43  is thus increased. The cooling fans  81  are allowed to receive a sufficient amount of air without redundancy or shortage. Air flow of a sufficient flow rate passes through the individual server computer  75 . The server computers  75  are reliably cooled. 
     Assume that the amount of the air supplied in response to the operation of the first ventilating unit  29  or the second ventilating unit  41  is excessive for the required amount of air into the cooling fans  81 . In this case, the air is introduced into the ventilation duct  79  from the front space  77  through the apertures  37 . The external air passes through the apertures  37 . This results in avoidance of a rise in the temperature of the first thermal sensors  38 . The difference in temperature is eliminated between the first thermal sensors  38  and the third thermal sensor  49 . The difference in temperature becomes smaller than the first temperature. The rotation speed of the first ventilators  31  or the second ventilators  43  is thus reduced. This results in stoppage of the supply of the airflow at an excessive flow rate to the cooling fans  81 . Excessive power consumption is avoided at the first ventilating unit  29  or the second ventilating unit  42 . 
     The first and second thermal sensors  38 ,  44  are configured to detect the temperature of the air inside the storage space  32 . The microcomputer  62  is configured to control the operation of the first and second ventilating units  29 ,  42  based on the detected temperature of the air. The flow rate of the first and second ventilating units  29 ,  42  is determined depending on the detected temperature of the air. The external air of an appropriate amount can thus always be introduced into the storage space  32 . The server computers  75  are efficiently cooled. 
     The first through opening  28  extends along the edge defined between first deadening wall member  26  and the second outer wall member  21   b , for example. The first thermal sensors  38  are arranged along the edge defined between the first deadening wall member  26  and the third outer wall member  21   c . The external air from the first through opening  28  hardly reaches the edge between the first deadening wall member  26  and the third outer wall member  21   c . The temperature thus tends to rise at a position near the edge between the first deadening wall member  26  and the third outer wall member  21   c . As long as the temperature is detected at such a position, it is possible to reliably prevent the server computers  75  from an excessive rise in temperature. This advantage is also available for the combination of the second through opening  41  and the second thermal sensors  44 . 
     The microcomputer  62  may exclude the maximum value and the minimum value of the detected temperature in calculating the average of the temperature of the first thermal sensors  38 . In general, a malfunctioning first thermal sensor  38  is expected to indicate a temperature significantly higher or lower than the average value. Accordingly, exclusion of the maximum value and the minimum value of the temperature leads to avoidance of the influence of the malfunction of the first thermal sensors  38  to the utmost. 
     An anemoscope may be attached to the aperture  37  in place of the aforementioned first thermal sensor  38 . As depicted in  FIG. 14 , for example, the anemoscope  82  includes a rotation shaft  83  extending in the in-plane direction of the partition board  35 . The rotation shaft  83  is connected to an encoder  84 . The encoder  84  outputs different voltage signals depending on the direction of the rotation of the rotation shaft  83 . Blades  85  are attached to the rotation shaft  83 . The blades  85  extend in parallel with the rotation shaft  83 . Here, the blades  85  are arranged at intervals of the central angle of 90 degrees, for example. The blades  85  are placed within a cylindrical windbreak  86 . The cylindrical windbreak  86  serves to define a ventilation opening  87  in combination with the edge of the aperture  37 . In the case where air passes through the ventilation opening  87  from the front space  77  toward the ventilation duct  79 , for example, the blades  85  receive airflow  88 . The rotation shaft  83  is driven to rotate in the anticlockwise direction, namely a normal direction  89 . On the contrary, in the case where air passes through the ventilation opening  87  from the ventilation dud  79  toward the front space  77 , the blades  85  receives airflow  91 . The rotation shaft  83  is driven to rotate in the clockwise direction, namely a reverse direction  92 . In this manner, it is possible to specify the direction of the airflow passing through the aperture  37 . In this case, the third thermal sensor  49  may be omitted. An anemoscope of any type other than the described one may be employed as the anemoscope  82 . 
       FIG. 15  schematically illustrates server room  101  as a storage unit according to a second embodiment of the present invention. The server room  101  includes a ceiling wall  102 , side walls  103  and a bottom wall  104 . The ceiling wall  102 , the side walls  103  and the bottom wall  104  in combination form a closed space. Specifically, the ceiling wall  102 , the side walls  103  and the bottom wall  104  in combination form a box-shaped enclosure. A floor  105  is placed between the ceiling wall  102  and the bottom wall  104 . The floor  105  extends within a horizontal plane. A bottom space  106  is defined between the floor  105  and the bottom wall  104 . A so-called structure corresponds to the enclosure of the storage unit. 
     A rack  107  is set on the floor  105  of the server room  101 . The rack  107  defines a pair of rack spaces  108 , for example. The front surfaces of the rack spaces  108  are opposed to each other, for example. An intake space  109  is defined between the rack spaces  108 . The intake space  109  is closed with a partition panel  110  and the floor  105 . The intake surface of the intake space  109  opens at the floor  105 . The intake space  109  is connected to the bottom space  106  through the intake surface. The intake space  109  and the rack spaces  108  in combination provide a ventilation duct. The intake surface of the intake space  109  corresponds to the intake surface of the ventilation duct. The rear surfaces of the rack spaces  108  provide the discharge surfaces of the ventilation duct. A server computer or computers  111  of a rack mount type can be mounted on the individual rack space  108 . An airflow generator, namely a cooling fan  112 , is incorporated in the individual server computer  111  so as to generate airflow from the front surfaces toward the rear surfaces of the rack spaces  108 . 
     Apertures  113  are formed in the partition panel  110 . The apertures  113  allow intake and discharge of airflow for the ventilation duct. A first thermal sensor  114  is placed at the individual aperture  113 . The first thermal sensor  114  is configured to detect the temperature of the airflow passing through the corresponding aperture  113 . Likewise, a second thermal sensor  115  is placed in the bottom space  106 . The second thermal sensor  115  is configured to detect the temperature of the air inside the bottom space  106 . 
     Air conditioners  117  are placed in the server room  101 . The air conditioners  117  suck a heated air from an interior space  118  above the floor  105 . The air conditioners  117  discharge a cooling air into the bottom space  106 . A circulating loop of airflow is thus established based on the air conditioners  117 , the bottom space  106 , the intake space  109 , the rack spaces  108  and the interior space  118 . A controller circuit is incorporated in the air conditioner  117 . The controller circuit is configured to control the flow rate of the air conditioner  117  in accordance with the detected temperature of the first and second thermal sensors  114 ,  115 . 
     During the operation of the individual server computer  111 , the cooling fan  112  operates in the individual server computer  111  in accordance with the inner temperature of the server computer  111 . The cooling fan  112  generates a horizontal airflow within the enclosure of the server computer  111  from the intake space  109  toward the interior space  118 . Airflow is generated from the intake surface toward the discharge surface. 
     The air conditioners  117  suck the heated air from the interior space  118 . Cooling air is discharged from the air conditioners  117  toward the bottom space  106 . Now, assume that “balance” is established between the flow rate of the cooling air discharged from the air conditioners  117  and the required amount of air into the cooling fans  112 . In this case, the first thermal sensors  114  are simultaneously exposed to the air in the intake space  109  and the air in the interior space  118 . The intake space  109  is filled with air of a temperature identical to that of the air in the bottom space  106 , while the interior space  118  is filled with the air heated with the generated heat of the server computers  111 . The temperature of the first thermal sensors  114  thus slightly rises from the external air. The difference in temperature between the first thermal sensors  114  and the second thermal sensor  115  becomes the first temperature or larger, but smaller than the second temperature. Accordingly, the cooling performance of the air conditioners  117  is maintained. The cooling fans  81  are allowed to receive a sufficient amount of air without redundancy or shortage. Airflow of a sufficient flow rate passes through the individual server computer  111 . 
     Next, assume that the amount of the cooling air discharged from the air conditioners  117  is insufficient for the required amount of air into the cooling fans  112 . In this case, airflow circulates in the space above the floor  105 . Specifically, as depicted in  FIG. 16 , air is introduced into the intake space  109  in the ventilation duct from the interior space  118  through the apertures  113 . The heated air passes through the apertures  113 . This results in a rise in the temperature of the first temperature sensors  114 . The difference in temperature between the first thermal sensors  114  and the second thermal sensor  115  becomes the second temperature or larger. Accordingly, the cooling performance of the air conditioner  117  is enhanced. The cooling fans  81  are allowed to receive a sufficient amount of cooling air without redundancy or shortage. Airflow of a sufficient flow rate passes through the individual server computer  111 . The individual server computer  111  is reliably cooled. 
     Assume that the amount of the cooling air discharged from the air conditioners  117  is excessive for the required amount of air into the cooling fans  112 . In this case, the air overflows the intake space  109 . Specifically, as depicted in  FIG. 17 , air overflows into the interior space  118  from the intake space  109  of the ventilation duct through the apertures  113 . The cooling air passes through the apertures  113 . This results in avoidance of a rise in the temperature of the first thermal sensors  114 . The difference in temperature is eliminated between the first thermal sensors  114  and the second thermal sensor  115 . The difference in temperature becomes smaller than the first temperature. Accordingly, the cooling performance of the air conditioners  117  is reduced. This results in stoppage of the supply of the cooling air at an excessive flow rate to the cooling fans  112 . Excessive power consumption is avoided at the air conditioners  117 . 
     All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relates to a showing of the superiority and inferiority of the invention. Although the embodiments of the present inventions have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.