Patent Publication Number: US-2011059687-A1

Title: Data center, cooling system, and method of cooling information technology device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2009-205327 filed on Sep. 4, 2009, the entire contents of which are incorporated herein by reference. 
     FIELD 
     The embodiments discussed herein are directed to a data center, a cooling system, and a method of cooling an information technology device. 
     BACKGROUND 
     In a data center where a rack device which mounts information technology (IT) devices such as a computer, a server, and a router is arranged, an air conditioning machine which takes in warm air and supplies cooling air is traditionally used to perform a cooling of IT devices. 
     For example as illustrated in  FIG. 10 , a popularly-used air conditioning machine  52  takes in air discharged from an IT device mounted on a rack device  50  in a data center and supplies, after cooling, cooling air under a floor in the data center. The IT device mounted in the rack device then takes in the cooling air supplied under the floor from its front surface by a fan and the like, makes the air pass through inside the device itself, and cools electronic devices including a central processing unit (CPU) and the like. After that, the IT device discharges air which is warmed due to the cooling of the electronic devices from its back surface. In this manner, cooling air and discharged air circulate depending on the air conditioning machine  52  and the cooling of the IT device in the rack device  50  is performed in the data center.  FIG. 10  illustrates an example of a circulation of cooling air and discharged air depending on an air conditioning machine arranged in a conventional data center. 
     Here, an example of a data center in which the rack device  50  and the air conditioning machine  52  are arranged will be represented.  FIG. 11  illustrates a housing room in a data center according to a conventional technique. As illustrated in  FIG. 11 , a plurality of rack devices  50  are arranged in the data center in such a way that air intake sides of IT devices face each other, in addition to a plurality of air conditioning machines  52 . By making a floor at the air intake sides of the IT devices formed by a grille, the IT devices can take in cooling air which is supplied under the floor from the air conditioning machines  52  via the grille. In addition, the IT devices discharge air used for cooling electronic devices mounted in itself from its back surface. Here, a site where the cooling air concentrates is referred to as a cool air zone  60  and a site where the discharged air concentrates is referred to as a discharged air zone  70 . 
     In recent years, higher functionality and performance of IT devices have caused a significant increase in a product electricity and a CPU electricity per unit area, thereby causing an increase in an amount of heat generation per unit area. Therefore, hazardous circumstances such as a system operation of exceeding a standard temperature of IT devices, an extreme temperature distribution in a data center, and a heat accumulated area are sometimes caused. In response, as a method for avoiding such hazardous circumstances, a method of arranging a local cooling unit on top of the rack device  50  of which heat generation amount is large and locally supplying cooling air and the like are adopted, for example. More detailed information about the conventional method can be obtained in technical documentations: John Niemann, “Hot-aisle. vs. cold-aisle containment”, White Paper #135 of American Power Conversion Corp., 2008; and White Paper LjTC040202TB of Hewlett-Packard Development Company, L.P., 2004/02. 
     However, there have been a problem of having a danger of a water leakage and a problem of a bad cooling efficiency in a data center in the conventional technique described above. 
     In a case of using a local cooling unit, for example, since a pipe for water and the like is supposed to be arranged near the ceiling at the rack device  50 , there is a chance of causing a break with an IT device wet when a water leakage occurs. Besides, for example in a case of additionally providing an IT device of which heat generation amount is large in the rack device  50  housing an IT device of which heat generation amount is not large, the air conditioning machine  52  sometimes operates in conjunction with a temperature of air discharged from the IT device of which heat generation amount is large. In this case, the IT device of which heat generation amount is not large is cooled more than necessary, causing a failure of the IT device contrary to the intention. 
     Moreover, not cooling air but warm discharged air is taken in an area denoted by a reference character “Z” in  FIGS. 10 and 11 , i.e., in the rack device  50  placed at a position away from the air conditioning machine  52  and thereby a heat accumulated area where an electronic device cannot be cooled is caused. As a result, an area (X) of which temperature is high is generated in the data center and thereby a cooling efficiency in the data center deteriorates. 
     SUMMARY 
     According to an aspect of an embodiment of the invention, a data center includes a housing room that houses an information technology device; an air conditioning machine that cools air in the housing room and supplies the air under a floor of the housing room; a grille that allows the air supplied under the floor to circulate in the housing room; and a rack device that houses the information technology device. In the data center, the rack device is arranged in such a way as to surround the grille, the information technology device is housed in the rack device in such a way as to take in the air from a space surrounded by the rack device via the grille and discharge air to the housing room, and the air conditioning machine is arranged at a side from which the information technology device discharges air. 
     According to another aspect of an embodiment of the invention, a data center includes a housing room that houses an information technology device; an air conditioning machine that cools air in the housing room and supplies the air under a floor of the housing room; a grille that allows the air supplied under the floor to circulate in the housing room; and a rack device that houses the information technology device. The rack device is arranged in such a way as to surround the air conditioning machine, the information technology device is housed in the rack device in such a way as to take in the air supplied under the floor via the grille and discharge air to an area surrounded by the rack device, and the air conditioning machine is arranged in the area surrounded by the rack device at a side from which the information technology device discharges air. 
     According to still another aspect of an embodiment of the invention, a data center includes a housing room that houses an information technology device; an air conditioning machine that cools air in the housing room and supplies the air under a floor of the housing room; a grille that allows the air supplied under the floor to circulate in the housing room; and a rack device that houses the information technology device. The rack device is arranged in such a way as to divide the housing room into a first area and a second area, the grille is arranged in the first area, the information technology device is housed in the rack device in such a way as to take in the air via the grille arranged in the first area and discharge air to the second area, and the air conditioning machine is arranged in the second area. 
     The object and advantages of the embodiment 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 embodiment, as claimed. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a view, seen from above, of a housing room in a data center according to a first embodiment; 
         FIG. 2  is a cross-sectional view a section of which is obtained by a cutting along a line A-A′ illustrated in  FIG. 1 ; 
         FIG. 3  is a view, seen from above, of a housing room in a data center according to a second embodiment; 
         FIG. 4  is a cross-sectional view a section of which is obtained by a cutting along a line B-B′ illustrated in  FIG. 3 ; 
         FIG. 5  is a view, seen from above, of a housing room in a data center according to a third embodiment; 
         FIG. 6  is a view, seen from above, of a housing room when a rack device  10  is arranged to form a rhombus shape; 
         FIG. 7  is a view, seen from above, of a housing room when a grille  7  and a rack device  10  are arranged in such a way as to be parallel to either direction of wall  5 ; 
         FIG. 8  illustrates an example of arranging a plate under a floor; 
         FIG. 9  illustrates an example of arranging a plate on a floor; 
         FIG. 10  illustrates an example of a circulation of cooling air and discharged air depending on an air conditioning machine arranged in a conventional data center; and 
         FIG. 11  illustrates a housing room in the data center according to the conventional technique. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Preferred embodiments of the present invention will be explained with reference to the accompanying drawings. It should be noted that the present invention is not limited to the embodiments. 
     [a] First Embodiment 
     First, a data center to be disclosed as an embodiment will be explained with reference to  FIG. 1 .  FIG. 1  is a view, seen from above, of a housing room in a data center according to a first embodiment. 
     As illustrated in  FIG. 1 , a housing room  2  in a data center is isolated from another housing room by being surrounded by a wall  5  and includes therein a grille  7 , a rack device  10 , an air conditioning machine  11 , and an entrance door  12 . 
     The grille  7  is arranged on a floor of the housing room  2  and has ventilation openings which allow air to circulate from a space under the floor to an inside of the housing room. The rack device  10  is a device which houses therein a plurality of information technology (IT) devices  10   a  and is arranged in such a way as to surround the grille  7  arranged under the floor of the housing room  2 . Air under the floor flows into the housing room  2  via the grille  7 , i.e., from a site of the grille  7 . 
     The IT device  10   a  takes in, by a fan and the like, cooling air which is cool air supplied from the air conditioning machine  11  and cools electronic devices such as a central processing unit (CPU) and a large scale integration (LSI) which are provided inside the IT device  10   a . The IT device  10   a  then discharges air which is warmed due to the cooling of the interior electronic devices from its back surface. 
     In addition, the IT device  10   a  has a light emitting diode (LED) which indicates a state of an electronic device housed therein and a state of a system provided by the IT device  10   a , and gives an alarm by turning on, for example, a red color LED in case of an abnormality. The IT device  10   a  is housed in the rack device  10  to take in air from a space surrounded by the rack device  10  via the grille  7  and discharge air into the housing room  2 . 
     The air conditioning machine  11  performs cooling by taking in air including the air discharged from the IT device  10   a  in the housing room  2  and supplies, after the cooling, cooling air under the floor of the housing room  2 . The air conditioning machine  11  is arranged at a side from which the IT device  10   a  discharges air in the housing room  2 . 
     The entrance door  12  is a door used by a maintenance person who performs maintenance in the data center, such as a maintenance of the IT device  10   a  housed in the rack device  10 , an expansion of the IT device  10   a , and an expansion of the rack device  10  itself. The entrance door  12  is arranged alongside the rack device  10 . 
     As described above, the rack device  10  surrounds the grille  7 , the housed IT device  10   a  is arranged in such a way that its air intake side faces the side of the grille  7 , and the air conditioning machine  11  is arranged in an area where discharged air of the IT device  10   a  concentrates. This configuration allows the rack device  10  to insulate a cool air zone  20  where cooling air flowing into the housing room  2  from the space under the floor via the grille  7  concentrates and a discharged air zone  30  where discharged air, which is warmed air after being used for cooling the IT device  10   a  concentrates. 
     Consequently, the IT device  10   a  can cool interior electronic devices by taking in cooling air from the cool air zone  20  in which discharged air cannot be contained easily and the air conditioning machine  11  can take in discharged air from the IT device  10   a  quickly. As a result, an IT device can be safely cooled without a necessity of using a local cooling unit and a cooling efficiency in the data center can be enhanced. In addition, since the air intake side, i.e., a front surface having the LED of the IT device  10   a  is located at a side of the cool air zone  20 , a maintenance person can look over LEDs of all IT devices by entering the cool air zone  20  from the entrance door  12 , which leads to a prompt detection of an alarm. 
     Next, an air flow in the housing room  2  illustrated in  FIG. 1  will be explained with reference to  FIG. 2 .  FIG. 2  is a cross-sectional view a section of which is obtained by a cutting along a line A-A′ illustrated in  FIG. 1 . As illustrated in  FIG. 2 , the cooling air supplied under the floor circulates in the housing room  2  via the grille  7  without mixing with discharged air and is taken in by the IT device  10   a  housed in the rack device  10 . Besides, the air (discharged air) discharged from the IT device  10   a  is taken in by the air conditioning machine  11  without mixing with the cooling air and flowing under the floor. Therefore, the IT device  10   a  can take in cooler air and moreover an accumulation of discharged air in the housing room  2  can be prevented. As a result, an occurrence of a heat accumulated area in which discharged air is taken in by the IT device  10   a  and therefore the IT device  10   a  cannot be cooled can be prevented as much as possible. 
     [b] Second Embodiment 
     An IT device can be cooled safely in a housing room in a data center to be disclosed in an embodiment of the invention even with an arrangement different from the first embodiment. Then, another example of the data center disclosed in the embodiment of the invention will be explained in a second embodiment with reference to  FIGS. 3 and 4 .  FIG. 3  is a view, seen from above, of a housing room in a data center according to the second embodiment. 
     As illustrated in  FIG. 3 , the rack device  10  is arranged in such a way as to surround the air conditioning machine  11 , the IT device  10   a  is housed in the rack device  10  in such a way as to take in air supplied under the floor via the grille  7  and discharge air to an area surrounded by the rack device  10 . Besides, the air conditioning machine  11  is arranged in an area surrounded by the rack device  10  and at a side from which the IT device  10   a  discharges air in such a way as to surround an air conditioning machine pipe space  11   a  in which a pipe of the air conditioning machine is housed. In other words, a front surface as an air intake side of the IT device  10   a  faces the side of the grille  7  and a back surface as an air discharge side faces the side of the air conditioning machine  11 . 
     This arrangement allows the rack device  10  to insulate a cool air zone  20  where cooling air flowing into the housing room  2  from the space under the floor via the grille  7  concentrates and a discharged air zone  30  where discharged air, which is warmed air after being used for cooling the IT device  10   a  concentrates. As a result, an IT device can be safely cooled without a necessity of using a local cooling unit and a cooling efficiency in the data center can be enhanced. In addition, since the discharged air zone according to the second embodiment, compared to the first embodiment, is an area surrounded by the rack device  10  and the air conditioning machine  11  is arranged in the discharged air zone, discharged air is more quickly taken in by the air conditioning machine  11 . Therefore, an increase in temperature in the entirety of the data center can be suppressed and a cooling efficiency can be enhanced, compared to the first embodiment. 
     Next, an air flow in the housing room  2  illustrated in  FIG. 3  will be explained with reference to  FIG. 4 .  FIG. 4  is a cross-sectional view a section of which is obtained by a cutting along a line B-B′ illustrated in  FIG. 3 . As illustrated in  FIG. 4 , cooling air supplied under the floor circulates upward from the floor via the grille  7  at a neighborhood of the wall  5 . Therefore, the cooling air is supposed to pass under the floor of the discharged air zone and does not mix with discharged air. In addition, since the air (discharged air) discharged from the IT device  10   a  is quickly taken in by the air conditioning machine  11 , the discharged air does not mix with the cooling air passing through the grille  7 . This configuration allows more strongly preventing an occurrence of a heat accumulated area compared to the first embodiment. 
     [c] Third Embodiment 
     The rack device can be arranged in the housing room in the data center disclosed in the embodiment of the invention so that an IT device can be cooled more efficiently than the first embodiment. Then, still another example of the data center disclosed in the embodiment of the invention will be explained in a third embodiment with reference to  FIG. 5 .  FIG. 5  is a view, seen from above, of a housing room in a data center according to the third embodiment. 
     As illustrated in  FIG. 5 , the grille  7 , the rack device  10 , and the air conditioning machine  11  are arranged in the housing room  2  in the data center according to the third embodiment in the same way as the first embodiment. In other words, the rack device  10  surrounds the grille  7 , the housed IT device  10   a  is arranged in such a way that its air intake side faces the side of the grille  7 , and the air conditioning machine  11  is arranged in an area where discharged air of the IT device  10   a  concentrates. The rack device  10  allows insulation between a cool air zone  20  via the grille  7  and a discharged air zone  30  which is used by the IT device  10   a  for the cooling. 
     However, the rack device  10  includes a high-heat-generating rack device  10   b  which has a plurality of high-performance IT devices  10   a  and of which heat generation amount is large, and a low-heat-generating rack device  10   c  which has a plurality of comparatively-low-performance IT devices  10   a  and of which heat generation amount is small, which is different from the first embodiment. The high-heat-generating rack device  10   b  discharges air of higher temperature than the low-heat-generating rack device  10   c.    
     In this case, the high-heat-generating rack device  10   b  is arranged at a place closer to the air conditioning machine  11  as illustrated in  FIG. 5 . By this arrangement, discharged air of higher temperature when discharged from the high-heat-generating rack device  10   b  can be taken in quickly by the air conditioning machine  11  without filling the housing room  2 . As a result, a cooling efficiency in the data center can further be enhanced and an improvement in temperature in the housing room  2  can be prevented, compared to the case in which the arrangement of the high-heat-generating rack device  10   b  and the low-heat-generating rack device  10   c  is not taken into consideration. 
     [d] Fourth Embodiment 
     While the example of arranging the rack device  10  to form a rectangular shape in the first embodiment, the embodiment is not limited thereto. For example, the grille  7  can arranged to form a rhombus shape and the rack device  10  can also be arranged to form a rhombus shape in such a way as to surround the grille  7 , as illustrated in  FIG. 6 . In addition, the shape is not limited to the rhombus and may be any shapes such as a round shape and a polygonal shape as long as the cool air zone  20  and the discharged air zone  30  can be insulated. Moreover, also concerning the arrangement example explained in the second embodiment, any shapes such as a rhombus shape, a round shape, and a polygonal shape may be adopted as long as the cool air zone  20  and the discharged air zone  30  can be insulated as described above.  FIG. 6  is a view, seen from above, of a housing room when the rack device  10  is arranged to form a rhombus shape. 
     [e] Fifth Embodiment 
     In the housing room in the data center disclosed in the embodiment of the invention, the rack device  10  is not necessarily arranged in such a way as to surround the grille  7 . For example, the grille  7  and the rack device  10  can be arranged in such a way as to be parallel to either direction of the wall  5 , as illustrated in  FIG. 7 . This arrangement allows a division into the cool air zone  20  and the discharged air zone  30 .  FIG. 7  is a view, seen from above, of a housing room when the grille  7  and the rack device  10  are arranged in such a way as to be parallel to either direction of wall  5 . 
     Even in this case, the IT device  10   a  is housed in the rack device  10  so that its air intake side faces the side of the grille  7  and takes in cooling air from the grille  7 . Besides, the air conditioning machine  11  is arranged at a side of the air discharge from the IT device  10   a , i.e., in the discharged air zone  30 , which is an area opposite to the grille  7  with respect to the rack device  10 . 
     This arrangement allows dividing the area into one cool air zone  20  and two discharged air zones  30 . Therefore, an IT device can be safely cooled and a cooling efficiency in a data center can be enhanced similarly to the first to fourth embodiments. 
     [f] Sixth Embodiment 
     Various methods can be adopted for allowing cooling air under the floor to pass easily through the grille  7  in the housing room in the data center disclosed in the embodiments of the invention. 
     For example, a plate  7   a  is arranged under the floor where the grille  7  is arranged in such a way as to be perpendicular to a surface of the grille  7  at a side opposite to the rack device  10 , as illustrated in  FIG. 8 . By this arrangement, the cooling air under the floor goes upward by hitting the plate  7   a  under the grille  7 . As a result, all the cooling air supplied under the floor from the air conditioning machine  11  can circulate in the housing room  2  via the grille  7  and be fed efficiently to the cool air zone  20 .  FIG. 8  illustrates the example of arranging a plate under the floor. 
     For example, a plate  7   b  is arranged on the floor where the grille  7  is arranged in such a way as to be perpendicular to a surface of the grille  7  at a side opposite to the rack device  10 , as illustrated in  FIG. 9 . This arrangement allows preventing the cooling air circulating from the space under the floor to the inside of the housing room  2  via the grille  7  from circulating to a direction opposite to the rack device  10 , i.e., to a direction away from the rack device  10 . In other words, the cooling air circulating in the housing room  2  is made to circulate to a side of the rack device  10 , i.e., to a direction to the rack device  10 . As a result, the IT device  10   a  housed in the rack device  10  can take in the cooling air efficiently. As a material of the plates  7   a  and  7   b  explained here, any materials such as a veneer plate, an acryl plate, and a concrete partition may be used.  FIG. 9  illustrates the example of arranging a plate on the floor. 
     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.