Abstract:
An air conditioning control apparatus for controlling an air conditioner in a room which accommodates a computer, includes obtaining repetitively a detected value of a total power consumption of the computer and the air conditioner and a detected value of a air temperature at the air inlet, storing the obtained values into a memory, determining an approximate expression representing a relation between the total power consumption and the air temperature on the basis of the values stored into the memory, determining a value of the air temperature corresponding to the lowest value of the total power consumption, by using the calculated approximate expression, and controlling the air conditioner so that the air temperature become equal the calculated air temperature.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2009-121432, filed on 19 May, 2009, the entire contents of which are incorporated herein by reference. 
       FIELD 
       [0002]    The present embodiments relates to an air conditioning control apparatus, an air conditioning control program, and an air conditioning control method. 
       BACKGROUND 
       [0003]    Conventionally, there are techniques related to an air conditioning control apparatus which circulates air in a room such as a datacenter or a machine room in order to cool IT equipments  303 A to P such as a computer in the room. 
         [0004]    However, in the above air conditioning control apparatus, efficiency of the IT equipments  303 A to P in terms of energy consumption has not been considered. Therefore, techniques aiming to improve energy efficiency of an air conditioning control apparatus have been proposed. 
         [0005]    For example, a technique has been proposed in which energy efficiency is improved by selecting a sensor considered to be important for determining a target temperature from among a plurality of control temperature sensors (as temperature detectors) installed in a room, setting the target temperature, and controlling an air conditioning adjustment function section such as a compressor and a blower. Also, a technique is proposed in which energy efficiency is improved by comparing an air map prepared in advance with an actually measured air map, and optimally controlling cool air distribution. 
         [0006]    Japanese Laid-open Patent Publication No. 2006-118837 and Japanese National Publication of International Patent Application No. 2006-504919 are examples of related art. 
         [0007]    However, in the above conventional techniques, there is no technique in which air conditioning is controlled in consideration of both energy efficiency of the air conditioning system and that of the IT equipment, although there is a technique in which efficiency of an air conditioning control apparatus alone is considered to control air conditioning for cooling IT equipment. 
         [0008]    Generally, energy efficiency of an air conditioning control apparatus improves as a setting temperature of the air conditioning increases. On the other hand, energy efficiency of IT equipment improves as the setting temperature of the air conditioning decreases. Therefore, in the conventional techniques which focus only on energy efficiency of the air conditioning system, it cannot be said that energy efficiency of the IT equipment is optimized. As described above, at present, it is not possible to control air conditioning while considering energy efficiency of both the air conditioning system and the IT equipment, in other words, while considering energy efficiency of the entire datacenter. 
       SUMMARY 
       [0009]    According to an aspect of the embodiments, an air conditioning control apparatus for controlling an air conditioner in a room which accommodates a computer having an air inlet and having an outlet, the air conditioning control apparatus includes a memory for storing a plurality of values of power consumption and a plurality of values of an air temperature, a first detector for detecting power consumption of the computer, a second detector for detecting power consumption of the air conditioner, a first temperature detector for detecting air temperature at the air inlet, and a processor for obtaining repetitively a detected value of the power consumption by each of the first detector and the second detector and a detected value of the air temperature by the first temperature detector, storing the obtained values into the memory, determining an approximate expression representing a relation between the total power consumption of the computer and the air conditioner and the air temperature on the basis of the values stored into the memory, determining a value of the air temperature at the air inlet corresponding to the lowest value of the total power consumption, by using the calculated approximate expression, and controlling the air conditioner so that the air temperature at the air inlet become equal the calculated air temperature. 
         [0010]    The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the 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 invention, as claimed. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0011]      FIG. 1  is a diagram for explaining a configuration of an air conditioning control apparatus according to a first embodiment. 
           [0012]      FIG. 2  is a diagram illustrating a relationship between total power consumption (total energy consumption) and temperature of intake air taken into IT equipments  303 A to P according to the first embodiment. 
           [0013]      FIGS. 3 to 6  are diagrams illustrating a process flow according to the first embodiment. 
           [0014]      FIG. 7  is a diagram for explaining a configuration of an air conditioning control apparatus according to a second embodiment. 
           [0015]      FIG. 8  is a diagram illustrating a relationship between total power consumption (total energy consumption) and a temperature of air blown from a conditioner according to the second embodiment. 
           [0016]      FIGS. 9 and 10  are diagrams illustrating a process flow according to the second embodiment. 
           [0017]      FIG. 11  is a diagram illustrating a computer which executes an air conditioning program. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0018]    Hereinafter, an embodiment of an air conditioning control apparatus, an air conditioning control method, and an air conditioning control program disclosed by the present application will be described in detail with reference to the drawings. Hereinafter, as an air conditioning control apparatus disclosed by the present application, an example of a system constituted by IT equipment a computer monitoring system and an air conditioning control apparatus is used. The technique disclosed by the present application is not limited by an embodiment described below as an embodiment of the air conditioning control apparatus, the air conditioning control method, and the air conditioning control program. 
       First Embodiment 
       [0019]    The air conditioning control apparatus according to the first embodiment generally controls air conditioning in a datacenter  305  where IT equipments  303 A to P such as computers or the like is installed. An outline of the air conditioning control apparatus according to the first embodiment will be described below. 
         [0020]    A characteristic formula is obtained by approximating total energy consumption in the datacenter  305  (energy consumption by IT equipments  303 A to Ps and energy consumption by air conditioners  301 A to D) by a predetermined function formula with an intake air temperature taken into IT equipments  303 A to P as a variable. By using this characteristic formula, an intake air temperature at which the total energy consumption value becomes minimum value is calculated, and a control value of the air conditioning is set so that the calculated intake air temperature is realized. Hereinafter, the air conditioning control apparatus according to the first embodiment will be specifically described. 
         [0021]    [Configuration of Air Conditioning Control Apparatus (First Embodiment)] 
         [0022]      FIG. 1  is a diagram for explaining a configuration of an air conditioning control apparatus according to the first embodiment. As illustrated in  FIG. 1 , the IT equipments monitoring system  100  monitors IT equipments  303 A to P such as computers and a storage installed in a datacenter  305 , and includes the IT equipment energy consumption measurement function section  110  and the IT equipment intake air temperature measurement function section  120 . 
         [0023]    The IT equipment energy consumption measurement function section  110  measures energy consumption of each of IT equipments  303 A to P in the datacenter  305 . Specifically, the IT equipment energy consumption measurement function section  110  obtains a current value, a voltage value, and the like used by IT equipments  303 A to P from detector in UPS (Uninterruptible Power Supply) installed inside each of IT equipments  303 A to P in the datacenter  305  at an energy consumption measurement timing. The IT equipment energy consumption measurement function section  110  calculates energy consumption of IT equipments  303 A to P from the obtained current value and voltage value, and stores the energy consumption in a storage section included inside the IT equipment energy consumption measurement function section  110  or the like. 
         [0024]    The IT equipment intake air temperature measurement function section  120  measures an intake air temperature of each IT equipments  303 A to P in the datacenter  305 . Specifically, the IT equipment intake air temperature measurement function section  120  obtains an intake air temperature of IT equipments  303 A to P from a temperature detectors such as sensors installed in each IT equipments  303 A to P in the datacenter  305  at an intake air temperature measurement timing, and stores the obtained intake air temperature in a storage section included inside the IT equipment intake air temperature measurement function section  120  or the like. 
         [0025]    The IT equipment energy consumption measurement function section  110  and the IT equipment intake air temperature measurement function section  120  perform measurement processing independently from each other. The same timing is set to the energy consumption measurement timing and the intake air temperature measurement timing in advance, and the energy consumption and the intake air temperature are stored so that the measurement results can be associated with each other. 
         [0026]    As illustrated in  FIG. 1 , the air conditioning control apparatus  200  controls an air conditioners  301 A to D installed in the datacenter  305 , and includes the air conditioning energy consumption measurement function section  210 , the optimal IT equipment intake air temperature calculation function section  220 , and the IT equipment temperature control function section  230 . 
         [0027]    The air conditioning energy consumption measurement function section  210  measures energy consumption of the air conditioners  301 A to D installed in the datacenter  305 . Specifically, the air conditioning energy consumption measurement function section  210  obtains a current value, a voltage value, and the like used by the air conditioners  301 A to D from a detector installed a distribution board having a power supply to the air conditioners  301 A to D in the datacenter  305  at an air conditioners  301 A to D energy consumption measurement timing. The air conditioning energy consumption measurement function section  210  calculates energy consumption of the air conditioners  301 A to D from the obtained current value and voltage value, and stores the energy consumption in a storage section included inside the air conditioning energy consumption measurement function section  210 . 
         [0028]    The optimal IT equipment intake air temperature calculation function section  220  obtains a characteristic formula which is obtained by approximating total energy consumption (energy consumption by IT equipments  303 A to P and energy consumption by air conditioners  301 A to D) in the datacenter  305  where the air conditioners  301 A to D is installed by a predetermined function formula with an intake air temperature taken into IT equipments  303 A to P as a variable, for a certain time period. By using this characteristic formula, an intake air temperature at which the total energy consumption value becomes minimum value is calculated. 
         [0029]    For example, as illustrated in  FIG. 2 , a case in which a quadratic equation having coefficient values “a=0.19, B=−6.60, and c=264.9” and a variable x of intake air temperature “Tit” is employed as a function formula to approximate the total energy consumption will be described below.  FIG. 2  is a diagram illustrating a relationship between the total power consumption (total energy consumption) and the temperature of intake air taken into IT equipments  303 A to P according to the first embodiment. 
         [0030]    In this case, the optimal IT equipment intake air temperature calculation function section  220  can obtain a total power (energy) consumption characteristic formula (1) by approximating the total energy consumption in the datacenter  305  where the air conditioners  301 A to D is installed by a quadratic function with an intake air temperature as a variable. 
         [0031]    Further, the optimal IT equipment intake air temperature calculation function section  220  can obtain an intake air temperature “Tit=17.4° C.” at which the total energy consumption becomes minimum by obtaining a formula (2) that is the first derivative formula of the total power consumption characteristic formula (1) and calculating a minimum value that can be obtained from the formula (2). 
         [0032]    The IT equipment temperature control function section  230  updates a control value of the air conditioners  301 A to D so that the intake air temperature calculated by the optimal IT equipment intake air temperature calculation function section  220  is realized. For example, in a case illustrated in  FIG. 2 , the IT equipment temperature control function section  230  updates a control value for adjusting a temperature of cooling-air blown from the air conditioners  301 A to D so that the intake air temperature of the IT equipments  303 A to P becomes “Tit=17.4° C.”. 
         [0033]    [Processing of First Embodiment] 
         [0034]      FIGS. 3 to 6  are diagrams illustrating a process flow according to the first embodiment. First, measurement processing of energy consumption of the IT equipments  303 A to P will be described with reference to  FIG. 3 . 
         [0035]    As illustrated in  FIG. 3 , the IT equipment energy consumption measurement function section  110  waits for a timing of measuring energy consumption of the IT the equipment (step S 1 ). 
         [0036]    When it reaches the timing of measuring energy consumption (step S 1 : Yes), the IT equipment energy consumption measurement function section  110  obtains a current value, a voltage value, and the like used by the IT equipments  303 A to P from the detector installed the UPS (Uninterruptible Power Supply) installed inside each IT equipments  303 A to P in the datacenter  305  (step S 2 ). 
         [0037]    The IT equipment energy consumption measurement function section  110  calculates energy consumption of the IT equipments  303 A to P from the obtained current value and voltage value (step S 3 ), and stores the energy consumption in a storage section included inside the IT equipment energy consumption measurement function section  110  or the like (step S 4 ). 
         [0038]    After storing the energy consumption of the IT equipments  303 A to P, the IT equipment energy consumption measurement function section  110  returns again to step S 1  described above, and waits for the timing of measuring energy consumption of the IT equipments  303 A to P. 
         [0039]    When the system is operating, by repeating the above described steps S 1  to S 4 , the IT equipment energy consumption measurement function section  110  performs the measurement of energy consumption of the IT equipments  303 A to P. 
         [0040]    The timing of measuring energy consumption of the IT equipments  303 A to P can be set by a user in advance to an interval such as one-minute interval, three-minute interval. 
         [0041]    Next, measurement processing of intake air temperature of the IT equipments  303 A to P will be described with reference to  FIG. 4 . As illustrated in  FIG. 4 , the IT equipment intake air temperature measurement function section  120  waits for a timing of measuring intake air temperature of the IT equipments  303 A to P (step S 11 ). 
         [0042]    When it reaches the timing of measuring intake air temperature (step S 11 : Yes), the IT equipment intake air temperature measurement function section  120  obtains an intake air temperature of the IT equipments  303 A to P from a sensor installed in each of IT equipments  303 A to P in the datacenter  305  (step S 12 ), and stores the obtained intake air temperature in a storage section included inside the IT equipment intake air temperature measurement function section  120  or the like (step S 13 ). 
         [0043]    After storing the intake air temperature, the IT equipment intake air temperature measurement function section  120  returns again to step S 11  described above, and waits for the timing of measuring intake air temperature of the IT equipments  303 A to P. 
         [0044]    When the system is operating, by repeating the above described steps S 11  to S 13 , the IT equipment intake air temperature measurement function section  120  performs the measurement of intake air temperature of the IT equipments  303 A to P. The timing of measuring intake air temperature of the IT equipments are set to the same as the timing of measuring energy consumption of the IT equipments  303 A to P so that the intake air temperature can be associated with the energy consumption of the IT equipments  303 A to P. 
         [0045]    Next, measurement processing of energy consumption of the air conditioners  301 A to D will be described with reference to  FIG. 5 . As illustrated in  FIG. 5 , the air conditioning energy consumption measurement function section  210  waits for a timing of measuring energy consumption of the air conditioners  301 A to D (step S 21 ). 
         [0046]    When it reaches the timing of measuring energy consumption of the air conditioners  301 A to D (step S 21 : Yes), the air conditioning energy consumption measurement function section  210  obtains a current value, a voltage value, and the like used by the air conditioners  301 A to D from the detector installed the distribution board (step S 22 ). 
         [0047]    The air conditioning energy consumption measurement function section  210  calculates energy consumption of the air conditioners  301 A to D from the obtained current value and voltage value (step S 23 ), and stores the energy consumption in a storage section included inside the air conditioning energy consumption measurement function section  210  (step S 24 ). 
         [0048]    After storing the energy consumption of the air conditioners  301 A to D, the air conditioning energy consumption measurement function section  210  returns again to step S 21  described above, and waits for the timing of measuring energy consumption of the air conditioners  301 A to D. 
         [0049]    When the system is operating, by repeating the above described steps S 21  to S 24 , the air conditioning energy consumption measurement function section  210  performs the measurement of energy consumption of the air conditioners  301 A to D. The timing of measuring energy consumption of the air conditioners  301 A to D is set to the same as the measurement timing of the IT equipment monitoring system  100  so that the energy consumption of the air conditioners  301 A to D can be associated with the measurement result of the IT equipment monitoring system  100 . 
         [0050]    Next, processing of updating a control value of the air conditioners  301 A to D will be described with reference to  FIG. 6 . As illustrated in  FIG. 6 , the optimal IT equipment intake air temperature calculation function section  220  waits for a timing of updating the control value of the air conditioners  301 A to D (step S 31 ). 
         [0051]    When it reaches the timing of updating the control value of the air conditioners  301 A to D (step S 31 : Yes), the optimal IT equipment intake air temperature calculation function section  220  obtains a target operation period for which the control value is updated (step S 32 ), and reads energy consumption of the air conditioners  301 A to D in the target operation period from the air conditioning energy consumption measurement function section  210  (step S 33 ). 
         [0052]    Further, the optimal IT equipment intake air temperature calculation function section  220  obtains energy consumption of the IT equipments  303 A to P in the target operation period from the IT equipment monitoring system  100  (step S 34 ), and obtains intake air temperatures of the IT equipments  303 A to P in the target operation period from the IT equipment monitoring system  100  (step S 35 ). 
         [0053]    The optimal IT equipment intake air temperature calculation function section  220  obtains a characteristic formula which is obtained by approximating the total energy consumption in the datacenter  305  where the air conditioners  301 A to D is installed by a quadratic function with an intake air temperature of the IT equipments  303 A to P as a variable for the target operation period (step S 36 ). The optimal IT equipment intake air temperature calculation function section  220  obtains an intake air temperature at which the total energy consumption value becomes minimum value by calculating a minimum value of the first derivative formula of the characteristic formula (step S 37 ). 
         [0054]    The IT equipment temperature control function section  230  updates the control value of the air conditioners  301 A to D so that the intake air temperature calculated by the optimal IT equipment intake air temperature calculation function section  220  is realized (step S 38 ). The optimal IT equipment intake air temperature calculation function section  220  returns again to step S 1  described above, and waits for the timing of updating the control value of the air conditioners  301 A to D. 
         [0055]    When the system is operating, by repeating the above described steps S 1  to S 8 , the optimal IT equipment intake air temperature calculation function section  220  performs the update of the control value of the air conditioners  301 A to D. The target operation period for which the control value is updated is a system operation period in which energy consumption for calculating an intake air temperature at which the total energy consumption value becomes minimum value is obtained. For example, a target operation period, such as a period from a previous update of the control value to this time&#39;s update of the control value, is set in the optimal IT equipment intake air temperature calculation function section  220  in advance. 
         [0056]    As described above, according to the first embodiment, a characteristic formula is obtained by approximating the total energy consumption in the datacenter  305  (energy consumption by the IT equipments  303 A to P and energy consumption by the air conditioners  301 A to D) by a predetermined function formula with an intake air temperature taken into IT equipments  303 A to P as a variable. By using this characteristic formula, an intake air temperature at which the total energy consumption value becomes minimum value is calculated, and the control value of the air conditioning is set so that the calculated intake air temperature is realized. 
         [0057]    In this way, by using a correlation (refer to  FIG. 2 ) between the total energy consumption in the datacenter  305  and the intake air temperature of the IT equipments  303 A to P and adjusting the intake air temperature of the IT equipments  303 A to P, it is possible to control the air conditioning so that the energy efficiency of the entire datacenter  305  including IT equipments  303 A to P, air conditioners  301 A to D becomes maximum. 
         [0058]    In the first embodiment described above, the air conditioning is controlled on the basis of detecting the intake air temperature. However, the controlling method is not limited to this, but the air conditioning may be controlled on the basis of detecting a temperature of air blow from the air conditioners  301 A to D. 
         [0059]    In addition, the conditioning may be controlled on the basis of the each temperature. Moreover, the conditioning may be controlled on the basis of temperature of outside of the room and the temperature of the intake of the IT equipments  303 A to P. 
       Second Embodiment 
       [0060]    In the first embodiment described above, a case is described in which the air conditioning is controlled so that the energy value efficiency of the entire datacenter  305  becomes maximum value by adjusting the intake air temperature of the IT equipments  303 A to P. However, the controlling method is not limited to this, but the air conditioning may be controlled to that the energy efficiency of the entire datacenter  305  becomes maximum by adjusting a temperature (blowing temperature) of air blown from the air conditioners  301 A to D. 
         [0061]      FIG. 7  is a diagram for explaining a configuration of an air conditioning control apparatus according to a second embodiment. As illustrated in  FIG. 7 , the air conditioning control apparatus  200  further includes the blowing temperature measurement function section  240 , the optimal blowing temperature calculation function section  250 , and the blowing temperature control function section  260 . 
         [0062]    The blowing temperature measurement function section  240  measures a blowing temperature of air blown from the air conditioners  301 A to D in the datacenter  305 . Specifically, the blowing temperature measurement function section  240  obtains a blowing temperature of the air conditioners  301 A to D from a detector as a sensor installed in each air conditioners  301 A to D in the datacenter  305 , and stores the obtained blowing temperature in a storage section included inside the blowing temperature measurement function section  240  or the like. 
         [0063]    The optimal blowing temperature calculation function section  250  obtains a characteristic formula which is obtained by approximating the total energy consumption in the datacenter  305  (energy consumption by the IT equipments  303 A to P and energy consumption by the air conditioners  301 A to D) by a predetermined function formula with a blowing temperature of the air conditioners  301 A to D as a variable. By using this characteristic formula, a blowing temperature at which the total energy consumption value becomes minimum value is calculated. 
         [0064]    For example, as illustrated in  FIG. 8 , a case in which a quadratic equation having coefficient values “a=0.19, B=−4.71, and c=264.9” and a variable x of blowing temperature “Tac” is employed as a function formula to approximate the total energy consumption will be described below.  FIG. 8  is a diagram illustrating a relationship between the total power consumption (total energy consumption) and a blowing temperature of the air conditioners  301 A to D according to the second embodiment. 
         [0065]    In this case, the optimal blowing temperature calculation function section  250  can obtain a total power (energy) consumption characteristic formula (1) by approximating the total energy consumption in the datacenter  305  where the air conditioners  301 A to D is installed by a quadratic function with a blowing temperature as a variable. 
         [0066]    Further, the optimal blowing temperature calculation function section  250  can obtain a blowing temperature “Tac=12.4° C.” at which the total energy consumption becomes minimum by obtaining a formula (2) that is the first derivative formula of the total power consumption characteristic formula (1) and calculating a minimum value that can be obtained from the formula (2). 
         [0067]    The blowing temperature control function section  260  updates the control value of the air conditioners  301 A to D so that the blowing temperature calculated by the optimal blowing temperature calculation function section  250  is realized. For example, in a case illustrated in  FIG. 8 , the blowing temperature control function section  260  updates the control value of the air conditioners  301 A to D so that the blowing temperature of the cooling air blown from the air conditioners  301 A to D becomes “Tac=12.4° C.”. 
         [0068]    [Processing of Air Conditioning Control Apparatus (Second Embodiment)] 
         [0069]      FIGS. 9 and 10  are diagrams illustrating a process flow according to the second embodiment. First, measurement processing of a blowing temperature of the IT equipments  303 A to P will be described with reference to  FIG. 9 . The measurement processing of energy consumption of the IT equipments  303 A to P ( FIG. 3 ) and the measurement processing of energy consumption of the air conditioners  301 A to D ( FIG. 5 ) are the same as those of the embodiment 1 described above, and thus the descriptions thereof will be omitted. 
         [0070]    As illustrated in  FIG. 9 , the blowing temperature measurement function section  240  waits for a timing of measuring a blowing temperature (step S 41 ). When it reaches the timing of measuring a blowing temperature (step S 41 : Yes), the blowing temperature measurement function section  240  obtains a blowing temperature of the cooling-air blown from the air conditioners  301 A to D from a sensor installed in each air conditioners  301 A to D in the datacenter  305  (step S 42 ), and stores the obtained blowing temperature in a storage section included inside the blowing temperature measurement function section  240  or the like (step S 43 ). 
         [0071]    After storing the blowing temperature, the blowing temperature measurement function section  240  returns again to step S 41  described above, and waits for the timing of measuring a blowing temperature of the air conditioners  301 A to D. 
         [0072]    When the system is operating, by repeating the above described steps S 41  to S 43 , the blowing temperature measurement function section  240  performs the measurement of a blowing temperature of the air conditioners  301 A to D. The timing of measuring a blowing temperature of the air conditioners  301 A to D is set to the same as the timing of measuring energy consumption of the air conditioners  301 A to D so that the blowing temperature of the air conditioners  301 A to D can be associated with the energy consumption of the air conditioners  301 A to D. 
         [0073]    Next, processing of updating a control value of the air conditioners  301 A to D will be described with reference to  FIG. 10 . As illustrated in  FIG. 6 , the optimal blowing temperature calculation function section  250  waits for a timing of updating the control value of the air conditioners  301 A to D (step S 51 ). 
         [0074]    When it reaches the timing of updating the control value of the air conditioners  301 A to D (step S 51 : Yes), the optimal blowing temperature calculation function section  250  obtains a target operation period for which the control value is updated (step S 52 ), and reads energy consumption of the air conditioners  301 A to D in the target operation period from the air conditioning energy consumption measurement function section  210  (step S 53 ). 
         [0075]    Further, the optimal blowing temperature calculation function section  250  reads blowing temperatures of the air conditioners  301 A to D in the target period from the blowing temperature measurement function section  240  (step S 54 ), and obtains intake air temperatures of the IT equipments  303 A to P in the target operation period from the IT equipment monitoring system  100  (step S 55 ). 
         [0076]    The optimal blowing temperature calculation function section  250  obtains a characteristic formula which is obtained by approximating the total energy consumption in the datacenter  305  where the air conditioners  301 A to D is installed by a quadratic function with a blowing temperature of the air conditioners  301 A to D as a variable for the target operation period (step S 56 ). The optimal blowing temperature calculation function section  250  obtains a blowing temperature at which the total energy consumption value becomes minimum value by calculating a minimum value of the first derivative formula of the characteristic formula (step S 57 ). 
         [0077]    The blowing temperature control function section  260  updates the control value of the air conditioners  301 A to D so that the blowing temperature calculated by the optimal blowing temperature calculation function section  250  is realized (step S 58 ). The optimal blowing temperature calculation function section  250  returns again to step S 1  described above, and waits for the timing of updating the control value of the air conditioners  301 A to D. 
         [0078]    As described above, according to the second embodiment, a characteristic formula is obtained by approximating the total energy consumption in the datacenter  305  (energy consumption by the IT equipments  303 A to P and energy consumption by the air conditioners  301 A to D) by a predetermined function formula with a blowing temperature of cooling air blown from the air conditioners  301 A to D as a variable. By using this characteristic formula, a blowing temperature at which the total energy consumption value becomes minimum value is calculated, and the control value of the air conditioning is set so that the calculated blowing temperature is realized. 
         [0079]    In this way, by using a correlation (refer to  FIG. 8 ) between the total energy consumption in the datacenter  305  and the blowing temperature of the air conditioners  301 A to D and adjusting the blowing temperature of the air conditioners  301 A to D, it is possible to control the air conditioning so that the energy efficiency of the entire datacenter  305  including IT equipments  303 A to P, air conditioners  301 A to D becomes maximum. 
         [0080]    However, the controlling method is not limited to this, but the conditioning may be controlled on the basis of temperature of outside of the room and the temperature of the air blow from the air conditioners  301 A to D. 
         [0081]    (1) Data Used to Calculate Control Value 
         [0082]    Although, in the above embodiments, a case is described in which the control value of the air conditioners  301 A to D is updated by using naturally occurring measurement data that is measured from IT equipments  303 A to P, air conditioners  301 A to D, and the like operating in the datacenter  305 , the updating method is not limited to this. 
         [0083]    For example, it is possible to update the control value of the air conditioners  301 A to D by estimating energy consumption of the IT equipments  303 A to P and the air conditioners  301 A to D using data provided from a manufacturer of the IT equipments  303 A to P and a manufacturer of the air conditioners  301 A to D, and using the estimated data. 
         [0084]    (2) Apparatus Configuration or the Like 
         [0085]    Each constituent element of the IT equipment monitoring system  100  and the air conditioning control apparatus  200  illustrated in  FIG. 1  is a functional conception, and the constituent elements do not necessarily need to be physically configured as illustrated in the figures. In other words, a specific form of distribution/integration of the air conditioning control apparatus  200  is not limited to the form illustrated in  FIG. 1 , and for example, the optimal IT equipment intake air temperature calculation function section  220  and the IT equipment temperature control function section  230  are integrated functionally or physically. Or, the IT equipment monitoring system  100  and the air conditioning control apparatus  200  are integrated functionally or physically. 
         [0086]    In such a way, all or part of the IT equipment monitoring system  100  and the air conditioning control apparatus  200  can be distributed/integrated functionally or physically by arbitrary units in accordance with various loads and usage situations. Further, all or any part of processing functions (refer to  FIGS. 3 to 6  and  FIGS. 9 and 10 ) performed in the air conditioning control apparatus  200  can be realized by a CPU and a program analyzed and executed by the CPU, or can be realized as hardware by wired logic. 
         [0087]    (3) Air Conditioning Control Method 
         [0088]    The air conditioning control method described below is realized by the IT equipment monitoring system  100  and the air conditioning control apparatus  200  described in the above embodiments. 
         [0089]    Specifically, a air conditioning control method is realized, which includes an equipment energy consumption measurement step for obtaining a current value and a voltage value supplied from a power supply apparatus to IT equipments  303 A to P and measuring energy consumption of the IT equipments  303 A to P from the obtained current value and voltage value (for example, refer to steps S 1  to S 4  in  FIG. 3 ), a system energy consumption measurement step for obtaining a current value and a voltage value supplied from a power supply section to an air conditioning system and measuring energy consumption of the air conditioning system from the obtained current value and voltage value (for example, refer to steps S 21  to S 24  in  FIG. 5 ), an intake air temperature measurement step for measuring intake air temperature of the IT equipments  303 A to P from a sensor installed in the IT equipments  303 A to P (for example, refer to steps S 11  to S 13  in  FIG. 4 ), an intake air temperature calculation step for calculating an intake air temperature at which the total energy consumption becomes minimum by using a characteristic formula obtained by approximating the total energy consumption that is the sum of the energy consumption of the IT equipments  303 A to P measured in the equipment energy consumption measurement step and the energy consumption of the air conditioners  301 A to D measured in the system energy consumption measurement step by a predetermined function formula with the intake air temperature measured in the intake air temperature measurement step as a variable (for example, refer to steps S 36  and S 37  in  FIG. 6 ), and an air conditioning control value setting step for setting a control value of the air conditioning system so that the intake air temperature calculated in the intake air temperature calculation step is realized (for example, refer to step S 38  in  FIG. 6 ). 
         [0090]    (4) Air Conditioning Control Program 
         [0091]    Various processing (for example, refer to  FIG. 6  or the like) of the air conditioning control apparatus  200  described in the above embodiments can also be realized by causing a computer system such as a personal computer and a work station to execute a program prepared in advance. Therefore, hereinafter, an example of a computer which executes an air conditioning program having the same function as that of the air conditioning control apparatus  200  described in the above embodiments will be described with reference to  FIG. 11 .  FIG. 11  is a diagram illustrating the computer which executes the air conditioning program. 
         [0092]    As illustrated in  FIG. 11 , the computer  300  is configured as the air conditioning control apparatus  200  by the input/output control section  310 , the HDD  320 , the RAM  330 , and the CPU  340  which are connected to each other through the bus  400 . 
         [0093]    The input/output control section  310  controls input/output of various information. The HDD  320  stores information for various processing performed by the CPU  340 . The RAM  330  temporarily stores various information. The CPU  340  performs various arithmetic processing. 
         [0094]    In the HDD  320 , as illustrated in  FIG. 11 , the air conditioning control program  321  and the air conditioning control data  322  which realize the same functions as those of the function sections of the air conditioning control apparatus  200  illustrated in  FIG. 1  are stored in advance. The air conditioning control program  321  can be appropriately distributed and stored in a storage section of another computer communicably connected through a network. 
         [0095]    When the CPU  340  reads the air conditioning control program  321  from the HDD  320  and develops the air conditioning control program  321  in the RAM  330 , the air conditioning control program  321  functions as the air conditioning control process  331  as illustrated in  FIG. 11 . 
         [0096]    Specifically, the air conditioning control process  331  reads the air conditioning control data  322  from the HDD  320 , develops the air conditioning control data  321  in an area assigned to the air conditioning control process  331  in the RAM  330 , and performs various processing on the basis of the developed data. 
         [0097]    The air conditioning control process  331  corresponds to processing performed by the optimal IT equipment intake air temperature calculation function section  220  in the air conditioning control apparatus  200  illustrated in  FIG. 1  and the optimal blowing temperature calculation function section  250  in the air conditioning control apparatus  200  illustrated in  FIG. 7 . 
         [0098]    The air conditioning control program  321  does not necessarily need to be stored in the HDD  320  from the beginning. 
         [0099]    For example, programs are stored in a “portable physical medium” such as a flexible disk (FD), a CD-ROM, a DVD disk, a magneto-optical disk, or an IC card inserted in the computer  300 . The computer  300  may read the programs from the portable physical medium and execute the programs. 
         [0100]    Further, programs are stored in “another computer (or computer)” connected to the computer  300  via a public line, the Internet, LAN, WAN, or the like. The computer  300  may read the programs from the above computer or computer and execute the programs. 
         [0101]    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 relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present invention 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.