Patent Publication Number: US-2012026686-A1

Title: Information processing apparatus system and method of controlling the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuing application, filed under 35 U.S.C. §111(a), of International Application PCT/JP2008/063202, filed Jul. 23, 2008, the contents of which are incorporated herein by reference. 
    
    
     FIELD 
     The embodiments discussed herein are related to an information processing apparatus system including: an information processing apparatus or apparatuses having a ventilator or ventilators configured to generate flow of coolant or a cooling medium from an intake surface of an enclosure to a discharge surface of the enclosure; and an air conditioner configured to supply the coolant toward the intake surface. 
     BACKGROUND 
     An information processing apparatus such as a so-called rack-mount server is well known. The rack-mount server or servers are mounted in a rack, for example. A ventilator is mounted in the individual rack-mount server. The ventilator is configured to generate the flow of coolant or a cooling medium from an intake surface of an enclosure to a discharge surface of the enclosure. The flow of coolant serves to prevent electronic components such as a CPU and a controller in the enclosure from suffering from a large increase in temperature.
     Publication 1: JP Utility Model Application Laid-open No. 6-29195   Publication 2: JP Patent Application Laid-open No. 2006-64303   Publication 3: JP Patent Application Laid-open No. 2003-166729   

     SUMMARY 
     Racks are placed in a room inside a data center. An air conditioner is disposed in the room. The air conditioner is designed to supply a cool air to intake surfaces of the individual rack-mount servers. However, the data center is not configured to supply a sufficient cool air to all the rack-mount servers. So-called hot spots are often generated in the room. This results in a concern that the electronic components suffer from an increase in temperature. 
     According to an aspect of the invention, an information processing apparatus system, includes: an information processing apparatus or apparatuses configured to measure the flow rate of coolant flowing from a coolant inflow surface of its enclosure to a coolant outflow surface of the enclosure; and a cooling apparatus configured to form a circulating path of the coolant from the coolant outflow surface to the coolant inflow surface, the cooling apparatus configured to control the discharged amount of the coolant based on the measured flow rate. 
     The information processing apparatus system enables a reliable supply of the coolant in an amount not excessive and without shortage to the information processing apparatus or apparatuses. The information processing apparatus or apparatuses can reliably be cooled. 
     A method of controlling an information processing apparatus system, the method comprises: measuring, at an information processing apparatus or apparatuses, flow rate of coolant flowing from a coolant inflow surface of an enclosure of the information processing apparatus or individual one of the information processing apparatuses to a coolant outflow surface of the enclosure; and controlling, based on the measured flow rate, the discharged amount of the coolant from a cooling apparatus configured to form a circulating path of the coolant from the coolant outflow surface of the enclosure to the coolant inflow surface of the enclosure. 
     In order to realize the information processing apparatus system, an information processing apparatus comprises: an enclosure enclosing an object to be cooled; an inflow temperature measuring section configured to measure the temperature of coolant flowing into the enclosure through a coolant inflow surface of the enclosure; an outflow temperature measuring section configured to measure the temperature of the coolant flowing out of the enclosure through a coolant outflow surface of the enclosure; a power consumption measuring section configured to measure the power consumption of the object; and a controlling section configured to calculate the flow rate of the coolant flowing from the coolant inflow surface to the coolant outflow surface based on the temperature measured at the inflow temperature measuring section, the temperature measured at the outflow temperature measuring section and the power consumption measured at the power consumption measuring section. 
     A method of cooling an information processing apparatus, the method comprises: measuring the temperature of coolant flowing into an enclosure through a coolant inflow surface of the enclosure, the enclosure enclosing an object to be cooled; measuring the temperature of the coolant flowing out of the enclosure through a coolant outflow surface of he enclosure; measuring the power consumption of the object; and calculating the flow rate of the coolant flowing from the coolant inflow surface to the coolant outflow surface based on the temperature measured at the inflow temperature measuring section, the temperature measured at the outflow temperature measuring section and the power consumption measured at the power consumption measuring 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 schematic view illustrating the entire structure of an information processing apparatus system according to a first embodiment; 
         FIG. 2  is an enlarged perspective view schematically illustrating the structure of a rack-mount server; 
         FIG. 3  is a block diagram schematically illustrating the control system of the information processing apparatus system; 
         FIG. 4  is an overall view of the information processing apparatus system for illustrating the flow of air; 
         FIG. 5  is a schematic view illustrating the structure of a rack-mount server according to another embodiment; 
         FIG. 6  is a schematic view illustrating the structure of a rack-mount server according to still another embodiment; 
         FIG. 7  is a schematic view illustrating the structure of a rack-mount server according to still another embodiment; 
         FIG. 8  is a schematic view illustrating the structure of a rack-mount server according to still another embodiment; 
         FIG. 9  is a schematic view illustrating the entire structure of an information processing apparatus system according to a second embodiment; 
         FIG. 10  is an enlarged perspective view schematically illustrating the structure of a blade server; and 
         FIG. 11  is a block diagram schematically illustrating the control system of the information processing apparatus system. 
     
    
    
     DESCRIPTION OF EMBODIMENT 
     Embodiment(s) of the present invention will be explained below with reference to the accompanying drawings. 
       FIG. 1  schematically illustrates the overall structure of an information processing apparatus system  11  according to a first embodiment. The information processing apparatus system  11  includes an information processing apparatus or apparatuses, namely a rack-mount server or servers  12 . The rack-mount server  12  includes an enclosure  13 . The enclosure  13  defines a hollow on a bottom plate  14  of a rectangular shape. The hollow extends from a front-side opening  15  to a rear-side opening  16 . The hollow is a space in the shape of a parallelepiped. The bottom plate  14  defines the bottom of the space of the parallelepiped. The front-side opening  15  defines the front surface of the space of the parallelepiped. The front-side opening  15  corresponds to a coolant inflow surface or an intake surface. The rear-side opening  16  defines the rear surface of the space of the parallelepiped. The rear-side opening  16  corresponds to a coolant outflow surface or a discharge surface. A pair of side surfaces of the space of the parallelepiped are covered with side panels  17 , respectively. The side panels  17  are opposed to each other, and extend between the front-side opening  15  and the rear-side opening  16 . The lower ends of the respective side panels  17  are coupled to the bottom plate  14 . The top surface of the space of the parallelepiped is covered with a top plate  18 . The top plate  18  is opposed to the bottom plate  14 , and extend between the front-side opening  15  and the rear-side opening  16 . Coolant or cooling medium, namely air flows into the enclosure  13  through the front-side opening  15 , as described later in detail. The air flows out of the enclosure  13  through the rear-side opening  16 . The rack-mount servers  12  are mounted on a rack  21 . The rack  21  defines a front opening  22  and a rear opening  23 . The front-side opening  15  faces the front opening  22  of the rack  21 . The rear-side opening  16  faces the rear opening  23  of the rack  21 . The rack  21  has a top panel  24 , left and right side panels  25  and bottom panels  26  for defining the front opening  22  and the rear opening  23 . 
     The information processing apparatus system  11  includes a cooling apparatus, specifically an air conditioner. The air conditioner  29  includes an intake opening  31  formed at the front of the air conditioner  29 . The intake opening  31  is opposed to the rear opening  23  of the rack  21 . A predetermined space is formed between the front of the air conditioner  29  and the back of the rack  21 . A discharge opening  32  is formed at the back of the air conditioner  29 . Air is sucked into the air conditioner  29  through the intake opening  31  and discharged out of the air conditioner  29  through the discharge opening  32 . 
     As depicted in  FIG. 2 , the front-side opening  15  is closed with a front panel  33  in the individual rack-mount server  12 . The rear-side opening  16  is closed with a rear panel  34 . Gratings  35  are formed in the front panel  33  and the rear panel  34  for intake and discharge of air. 
     A first space  37  is defined in a parallelepiped-shaped space  36  at a position closest to the front-side opening  15 . A second space  38  is defined in the parallelepiped-shaped space  36  at a position closest to the rear-side opening  16 . A third space  39  is defined between the first space  37  and the second space  38 . The third space  39  is interposed between the first space  37  and the second space  38 . Specifically, the parallelepiped-shaped space  36  is divided into the first space  37 , the third space  39  and the second space  38  in this sequence from the front end. 
     Electronic components having a relatively small height are placed in the first space  37 . Such electronic components include CPU chip packages  41  and controller chip packages  42 , for example. The CPU chip packages  41  and the controller chip packages  42  are mounted on a printed wiring board. The printed wiring board extends along a horizontal plane. A motherboard is in this manner established. The CPU chip packages  41  and the controller chip packages  42  include heat sinks, for example, respectively. The individual heat sink includes cooling fins. The cooling fins extend in parallel with the side surface of the parallelepiped-shaped space  36 . A set of memory modules  43 , a set of PCI cards  44 , hard disk drives (HDDs), and the like are placed in the second space  38 , for example. The motherboard as well as the HDDs generate heat during operations. 
     A fan unit  47  is placed in the third space  39 . The fan unit  47  separates the first space  37  and the second space  38  from each other. The fan unit  47  includes axial fans  48 . The individual axial fan  48  rotates blades around a rotation axis  49  extending in parallel with the bottom surface of the parallelepiped-shaped space  36 . Here, pairs of the axial fans  48 ,  48 , namely the front and rear axial fans  48 ,  48  having the coaxial rotation axes  49 ,  49  are arranged in three rows. The axial fans  48 , six in total, are coupled to one another. Airflow is generated from the first space  37  to the second space  38  in response to the rotation of the blades. 
     An inflow temperature sensor  51  and an outflow temperature sensor  52  are placed in the enclosure  13  of the rack-mount server  12 . The inflow temperature sensor  51  is located in the front-side opening  15 , namely at the intake surface. The inflow temperature sensor  51  is configured to detect the temperature of air flowing into the enclosure  13  through the front-side opening  15 , namely the intake air temperature. The inflow temperature sensor  51  provides an inflow temperature measuring section. On the other hand, the outflow temperature sensor  52  is located in the rear-side opening  16 , namely at the discharge surface. The outflow temperature sensor  52  is configured to detect the temperature of air flowing out of the enclosure  13  through the rear-side opening  16 , namely the discharged air temperature. The outflow temperature sensor  52  provides an outflow temperature measuring section. 
       FIG. 3  illustrates the control system of the information processing apparatus system  11 . The individual rack-mount server  12  includes a controlling section, namely a controller  53 . The aforementioned inflow temperature sensor  51  and outflow temperature sensor  52  are connected to the controller  53 . An intake temperature signal and a discharge temperature signal are supplied to the controller  53  from the inflow temperature sensor  51  and the outflow temperature sensor  52 . The intake temperature signal specifies the intake air temperature. The discharge temperature signal specifies the discharged air temperature. 
     A power consumption measuring section  54  is connected to the controller  53 . The power consumption measuring section  54  is configured to measure the power consumption for the individual electronic components or for the entire structure of the server. The power consumption measuring section  54  supplies a power consumption amount signal to the controller  53 . The power consumption amount signal specifies the amount of the power consumption. The quantity of heat or heating energy of the electronic component or the server can be calculated based on the amount of the power consumption. 
     An airflow rate calculating section  55  is established in the controller  53 . The intake temperature signal, the discharge temperature signal and the power consumption amount signal are supplied to the airflow rate calculating section  55 . The airflow rate calculating section  55  calculates the quantity of heat at the electronic component or components based on the amount of the power consumption. The airflow rate calculating section  55  is configured to calculate the flow rate U of the airflow based on the intake air temperature T in , the discharged air temperature T out , the amount P of the power consumption, the air density ρ, and the specific heat C p  in accordance with the following equation: 
     
       
         
           
             
               
                 
                   
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     The airflow rate calculating section  55  outputs an airflow rate information signal. The airflow rate information signal specifies the airflow rate U (volume per unit time). When the airflow rate calculating section  55  calculates the airflow rate, the airflow rate calculating section  55  refers to the mounting position and/or the number of heat generating components such as the CPU chip package and the HDDs, and the mounting position and/or the number of the option boards. This type of information may be stored in a memory installed in the controller  53 , for example. 
     One of the rack-mount servers  12  is designated as a controller server  56 . The remainder of the rack-mount servers  12  is connected to the controller server  56 . LAN interfaces  57  are utilized to establish such connection, for example. An airflow rate aggregating section  58  is established in the controller  53  of the controller server  56 . The airflow rate information signals are supplied to the airflow rate aggregating section  58  from the individual rack-mount servers  12 . The airflow rate aggregating section  58  aggregates the airflow rate for the entire rack  21  based on the airflow rate information signals. 
     A discharged amount calculating section  59  is established in the controller  53  of the controller server  56 . The discharged amount calculating section  59  calculates the discharged amount of the air conditioner  29  based on the aggregated airflow rate. This discharged amount corresponds to the flow rate of a cooling air discharged from the discharge opening  31  of the air conditioner  29 . The discharged amount calculating section  59  generates a control signal based on the calculated discharged amount. The control signal specifies the discharged amount. The discharged amount is set at 1.1-1.2 times the aggregated airflow rate approximately. When the discharged amount calculating section  59  calculates the discharged amount, the discharged amount calculating section  59  refers to the type of the air conditioner  29 , the type of the rack  21 , the distance between the rack  21  and the air conditioner  29 , and other environmental information. This type of information may be stored in a memory installed in the controller  53 , for example. 
     The controller  53  of the controller server  56  is connected to a controller  61  of the air conditioner  29 . The LAN interfaces  57  are utilized to realize such connection, for example. A revolution speed calculating section  62  is established in the controller  61  of the air conditioner  29 . The aforementioned control signal is supplied to the revolution speed calculating section  62 . The revolution speed calculating section  62  calculates the revolution speed of the individual fans  63  based on the discharged amount. The discharged amount is determined based on the revolution speed of the fans  63 . A relationship is determined between the revolution speed of the fans  36  and the flow rate. Such a relationship is stored in a memory installed in the controller  61 , for example. When the revolution speed calculating section  62  calculates the revolution speed, the revolution speed calculating section  62  refers to the type of the air conditioner  29 , component information such as a filter, and other environmental information. This type of information may be stored in a memory installed in the controller  61 , for example. 
     A driving signal generating section  65  is established in the controller  61  of the air conditioner  29 . The driving signal generating section  65  generates a driving signal based on the revolution speed obtained at the revolution speed calculating section  62 . When the generated driving signal is supplied to the individual fans  63 , the fans  63  are forced to rotate at the designated revolution speed. The discharged amount of the air conditioner  29  is in this manner managed based on the control of the revolution speed. 
     As depicted in  FIG. 4 , when the fan units  47  operate, the flow of coolant, namely air is generated in the individual rack-mount server  12  from the front-side opening  15  namely the intake surface to the rear-side opening  16  namely the discharge surface. The air receives heat from objects to be cooled, such as the motherboard and the HDDs. The airflow serves to cool the motherboard and the HDDs. The airflow flows out of the enclosure  13  through the rear-side opening  16 . 
     The heated air is sucked into the air conditioner  29  through the intake opening  31 . The air conditioner  29  cools the air based on a conventional refrigeration cycle. The cool air is discharged from the discharge opening  32 . The air conditioner  29  forms a circulating path of the air from the rear-side opening  16  of the rack-mount server  12  to the front-side opening  15  of the rack-mount server  12 . The air conditioner  29  in this manner works to supply the cool air to the rack-mount servers  12 . 
     When the individual rack-mount servers  12  operate, the motherboards and the HDDs generate heat. The discharged air temperature rises. The controller  53  controls the flow rate of air discharged from the axial fans  48  based on a temperature difference between the discharged air temperature and the intake air temperature. When the temperature difference increases, the controller  53  increases the revolution speed of the blades around the rotation axes  49 . To the contrary, when the temperature difference decreases, the controller  53  reduces the revolution speed of the blades around the rotation axes  49 . The flow rate of the airflow flowing through the parallelepiped-shaped space  36  varies in the individual rack-mount server  12 . 
     Here, a brief description will be made on a method of controlling the discharged amount of the air conditioner  29 . First of all, the controller server  56  requests the individual rack-mount servers  12  to measure the airflow rate in the individual rack-mount servers  12 . Instruction signals are supplied to the individual rack-mount servers  12 , respectively, through the LAN interfaces  57 . The controller  53  receives the intake temperature signal and the discharge temperature signal from the inflow temperature sensor  51  and the outflow temperature sensor  52 , respectively, in response to the reception of the instruction signal. At the same time, the controller  53  obtains the power consumption amount signal from the power consumption measuring section  54 . The airflow rate calculating section  55  calculates the flow rate of the airflow based on the intake air temperature, the discharged air temperature and the amount of the power consumption in the aforementioned manner. The airflow rate calculating section  55  outputs the airflow rate information signal. The airflow rate information signal is supplied to the controller server  56  through the LAN interfaces  57 . 
     The controller  53  of the controller server  56  receives the airflow rate information signals from all the rack-mount servers  12 . The airflow rate aggregating section  58  aggregates the airflow rate for the rack-mount server or servers  12  in operation in the rack  21 . The airflow rate is summed. The required airflow rate for the rack  21  is in this manner calculated. The discharged amount calculating section  59  calculates the discharged amount of the air conditioner  29  based on the required airflow rate. Here, the required airflow rate is multiplied by a predetermined coefficient. The predetermined coefficient is set in a range between 1.1 and 1.2 approximately, for example. The discharged amount is in this manner set larger than the required airflow rate. The discharged amount calculating section  59  generates the control signal based on the calculated discharged amount. The generated control signal is outputted to the air conditioner  29  through the LAN interfaces  57 . 
     The controller  61  of the air conditioner  29  controls the action of the fans  63  in response to the reception of the control signal. The revolution speed calculating section  62  determines the revolution speed of the fans  63  based on the discharged amount. The driving signal generating section  65  generates the driving signal based on the determined revolution speed. The fans  63  operate at the designated revolution speed. As a result, the discharged amount of the air conditioner  29  is controlled. The cool air is in this manner supplied to the individual rack-mount servers  12  in an amount not excessive and without shortage. Generation of hot spots is avoided. An efficient cooling of the rack-mount servers  12  is realized. As a result, the power consumption can be reduced. 
     As depicted in  FIG. 5 , a plurality of the inflow temperature sensors  51  and the outflow temperature sensors  52  may be disposed in the front-side opening  15  and the rear-side opening  16  in the rack-mount server  12 , for example. Specifically, measurement points are located in predetermined regions, respectively, in the front-side opening  15  and the rear-side opening  16 . The temperature of air is measured at the respective measurement points. The individual inflow temperature sensor  51  outputs the intake temperature signal. The individual outflow temperature sensor  52  outputs the discharge temperature signal. The outputted intake temperature signal and discharge temperature signal are supplied to the controller  53 . 
     When the airflow rate calculating section  55  in the controller  53  calculates the airflow rate, the airflow rate calculating section  55  determines the intake air temperature T in  based on all the intake temperature signals. When the airflow rate calculating section  55  determines the intake air temperature T in , the airflow rate calculating section  55  calculates the average value of the temperatures specified in the intake temperature signals. Likewise, when the airflow rate calculating section  55  calculates the airflow rate, the airflow rate calculating section  55  determines the discharged air temperature T out  based on all the discharge temperature signals. When the airflow rate calculating section  55  determines the discharged air temperature T out , the airflow rate calculating section  55  calculates the average value of the temperatures specified in the discharge temperature signals. The enhanced accuracy of the intake air temperature and the discharged air temperature in this manner serves to allow the airflow rate calculating section  55  to determine the flow rate U of the airflow with high accuracy. 
     Furthermore, a constriction  65  may be defined in at least one of the front-side opening  15  and the rear-side opening  16  in the rack-mount server  12 , as depicted in  FIG. 6 , for example. The constriction  65  is configured to narrow the passage of the airflow in the parallelepiped-shaped space  36 . As a result, the range of the airflow is reduced. The temperature of the airflow can be specified with high accuracy with less measurement points. The airflow rate calculating section  55  is allowed to determine the flow rate U of the airflow with higher accuracy. 
     The airflow rate can be calculated based on the revolution speed of the axial fans  48  in the rack-mount server  12 . In this case, the revolution speed is specified for the individual axial fans  48 . A revolution speed signal is supplied to the airflow rate calculating section  55  from the axial fan  48 . The revolution speed signal specifies the revolution speed of the blades around the rotation axis  49 . In the case where the revolution speed of the individual axial fan  48  is independently controlled, the revolution speed signals may be supplied to the airflow rate calculating section  55  from the individual axial fans  48 , as depicted in  FIG. 7 . In the case where the revolution speed is commonly controlled for a set of the axial fans  48 , the revolution speed signal may be supplied to the airflow rate calculating section  55  from any one of the axial fans  48 . The axial fan  48  may employ a revolution speed sensor such as an encoder so as to determine the revolution speed of the axial fan  48 , for example. The revolution speed may be determined based on the voltage value, the current value, the width of the pulse, or the like, of the driving signal supplied to the axial fan  48  in place of the aforementioned revolution speed sensor. The airflow rate calculating section  55  in this manner calculates the airflow rate based on the revolution speed signal. The airflow rate is previously determined depending on the magnitude of the revolution speed in the individual axial fan  48 . Such a relationship between the revolution speed and the airflow rate may be stored in a memory installed in the controller  53 , for example. 
     Furthermore, an anemometer  66  may be installed in the rack-mount server  12 , as depicted in  FIG. 8 , for example. The anemometer  66  may be disposed in any one of the front-side opening  15  and the rear-side opening  16 , for example. The anemometer  66  is configured to detect the speed of the airflow. The anemometer  66  generates a airflow speed value signal based on the detected value. The airflow speed value signal is supplied to the airflow rate calculating section  55  from the anemometer  66 . The airflow rate calculating section  55  determines the speed of the airflow based on the speed of the airflow and the sectional area of the opening. The sectional area may be specified at the front opening  16  and the rear-side opening  16 . The value of the sectional area is previously stored in a memory in the controller  53 . It is preferable to define the constriction  65  in the enclosure  13  for disposition of the anemometer in the aforementioned manner. The anemometer may be located in the constriction  65 . The constriction  65  works to equalize the speed of the airflow over the sectional area. 
       FIG. 9  schematically illustrates the overall structure of an information processing apparatus system  11   a  according to a second embodiment. The information processing apparatus system  11   a  includes so-called blade servers  71 . The blade server  71  includes an enclosure, namely a chassis  72 . The chassis  72  defines a hollow extending from a front-side opening  73  to a rear-side opening  74 . The front-side opening  73  corresponds to a coolant inflow surface or intake surface. The rear-side opening  74  corresponds to a coolant outflow surface or a discharge surface. The chassis  72  is mounted on the rack  21 . The rack  21  defines the front opening  22  and the rear opening  23 . The front-side opening  73  faces the front opening  22  of the rack  21 . The rear-side opening  74  faces the rear opening  23  of the rack  21 . The rack  21  has a top panel  24 , left and right side panels  25  and bottom panels  26  for defining the front opening  22  and the rear opening  23 . Like reference numerals or characters are attached to components or structure equivalent to those of the aforementioned information processing apparatus system  11 . 
     A single backplate  75  is installed in the chassis  72 . The backplate  75  extends in the vertical direction. The backplate  75  serves to divide a parallelepiped-shaped space inside the chassis  72  into a front-side space  76  and a rear-side space  77 . A server blade or blades  78 , namely an information processing apparatus unit or units, are placed in the front-side space  76 . The server blades  78  are inserted into the chassis  72  in the vertical attitude. The server blades  78  are coupled to the front surface of the backplate  75 . Power source units  81 , a fan unit  82 , a management blade, not depicted, and the like, are placed in the rear-side space  77 . The power source units  81 , the fan unit  82  and the management blade are coupled to the back surface of the backplate  75 . The backplate  75  serves to distribute the electric power, supplied from the power source units  81 , to the individual server blades  78 . The fan unit  82  includes axial fans, for example, in the same manner as the aforementioned fan unit  47 . The individual axial fan rotates blades around a rotation axis extending along the horizontal imaginary plane from the front-side to the rear-side. Airflow is generated from the front-side opening  73  to the rear-side opening  74  in response to the rotation of the blades. 
     As depicted in  FIG. 10 , a hollow is defined in an enclosure  86  in the individual server blade  78 . The hollow extends from a front-side opening  84  of the enclosure  86  to a rear-side opening  85  of the enclosure  86 . The front-side opening  84  is closed with a front panel  87 , for example. The rear-side opening  85  is closed with the backplate  75 . Gratings  88  are formed in the front panel  87  and the backplate  75  for intake and discharge of air. A motherboard  89  and hard disk drives (HDDs)  91  are placed in the hollow. 
     The individual server blade  78  includes an inflow temperature sensor  92  located in the front-side opening  84 . Likewise, the individual server blade  78  includes an outflow temperature sensor  93  located in the rear-side opening  85 . The inflow temperature sensor  92  is configured to detect the temperature of air flowing into the enclosure  86  through the front-side opening  84 , namely the intake air temperature. The inflow temperature sensor  92  provides an inflow temperature measuring section. The outflow temperature sensor  93  is configured to detect the temperature of air flowing out of the enclosure  86  through the rear-side opening  85 , namely the discharged air temperature. The outflow temperature sensor  93  provides an outflow temperature measuring section. 
     As depicted in  FIG. 11 , the individual server blade  78  includes a controlling section, namely a controller  94 . The aforementioned inflow temperature sensor  92  and outflow temperature sensor  93  are connected to the controller  94 . An intake temperature signal and a discharge temperature signal are supplied to the controller  94  from the inflow temperature sensor  92  and the outflow temperature sensor  93 . The intake temperature signal specifies the intake air temperature. The discharge temperature signal specifies the discharged air temperature. 
     A power consumption measuring section  95  is connected to the controller  94 . The power consumption measuring section  95  is configured to measure the power consumption for the individual electronic components or for the individual blade servers in the same manner as described above. The power consumption measuring section  95  supplies a power consumption amount signal to the controller  94 . The power consumption amount signal specifies the amount of the power consumption. The quantity of heat or heating energy of the electronic component or the blade server can be calculated based on the amount of the power consumption. 
     An airflow rate calculating section  96  is established in the controller  94 . The intake temperature signal, the discharge temperature signal and the power consumption amount signal are supplied to the airflow rate calculating section  96 . The airflow rate calculating section  96  calculates the quantity of heat at the electronic component or components based on the amount of the power consumption in the same manner as described above. The airflow rate calculating section  96  is configured to calculate the flow rate of the airflow in the same manner as described above. 
     An airflow rate aggregating section  97  is established in the backplate  75 . The airflow rate information signals are supplied to the airflow rate aggregating section  97  from the individual server blades  78 . The airflow rate aggregating section  97  aggregates the airflow rate for the entire blade server  71  based on the airflow rate information signals. 
     One of the blade servers  71  is designated as a controller server  98 . The remainder of the blade servers  71  is connected to the controller server  98 . LAN interfaces  57  are utilized to establish such connection in the same manner as described above. The airflow rate information signals are supplied to the airflow rate aggregating section  97  of the controller server  98  from the airflow rate aggregating sections  97  of the individual blade servers  71 , respectively. The airflow rate aggregating section  97  of the controller server  98  aggregates the airflow rate for the entire rack  21  based on the airflow rate information signals supplied from the airflow rate aggregating sections  97 . 
     A discharged amount calculating section  99  is established in the backplate  75  of the controller server  98 . The discharged amount calculating section  99  calculates the discharged amount of the air conditioner  29  based on the aggregated airflow rate in the same manner as described above. The discharged amount calculating section  99  generates a control signal based on the calculated discharged amount in the same manner as the aforementioned discharged amount calculating section  59 . The backplate  75  of the controller server  98  is connected to the controller  61  of the air conditioner  29 . 
     When the fan units  82  operate, the flow of coolant, namely air is generated in the individual server blades  78  from the front-side opening  84  namely the intake surface to the rear-side opening  85  namely the discharge surface. The air receives heat from objects to be cooled, such as the motherboard  89  and the HDDs  91 . The airflow serves to cool the motherboard  89  and the HDDs  91 . The airflow flows out of the enclosure  86  through the rear-side opening  85 . 
     The heated air is sucked into the air conditioner  29  through the intake opening  31 . The air conditioner  29  cools the cooling medium namely air based on a conventional refrigeration cycle. The cool air is discharged from the discharge opening  32 . The air conditioner  29  forms a circulating path of the air from the rear-side opening  85  of the server blade  78  to the front-side opening  84  of the server blade  78 . The air conditioner  29  in this manner works to supply the cool air to the individual server blades  78 . In this case, the discharged amount of the air conditioner is controlled in the aforementioned manner. 
     All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concept 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 relate 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.