US20100297927A1

US20100297927A1 - Air conditioning installation

Info

Publication number: US20100297927A1
Application number: US12/782,886
Authority: US
Inventors: Ikuro NAGAMATSU; Junichi Ishimine; Seiichi Saito; Masahiro Suzuki; Tadashi Katsui; Yuji Ohba; Nobuyoshi Yamaoka; Akira Ueda; Yasushi Uraki
Original assignee: Fujitsu Ltd
Current assignee: Fujitsu Ltd
Priority date: 2009-05-22
Filing date: 2010-05-19
Publication date: 2010-11-25
Also published as: JP5359551B2; GB201008324D0; GB2470481B; JP2010270998A; CN101893291A; GB2470481A; CN101893291B

Abstract

An installation for cooling an electronic device provided on a floor in a room includes an underfloor space below the floor; an air conditioner for sending air to the underfloor space; a first opening provided in the floor and adjacent to the electronic device, for sending air from the underfloor space to the room; and a second opening provided in the floor and adjacent to the air conditioner, the second opening being configured to cause the air pressure of the lower side of the second opening to be lower than the air pressure of the upper side of the second opening.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2009-124607, filed on May 22, 2009, the entire contents of which are incorporated herein by reference.

FIELD

The embodiments discussed herein are related to an air conditioning installation for sending cooled air to a bottom-floor level and then supplying the cooled air to electronic equipment installed on a raised-floor level.

BACKGROUND

Hitherto, a data center that supplies cold air from a bottom-floor level to electronic equipment through a panel has been utilized. A data center of this type has a double-floor configuration including a bottom-floor level and a raised-floor level and electronic equipment is disposed on the raised-floor level. In a data center configured as mentioned above, electronic equipment mounted on a rack tends to generate more heat in less space, causing heat generated per server rack to increase and hot spots with air exhausted from the electronic equipment and flowing around the rack to occur.
Here, air flows in a data center will be described with reference to FIG. 14. As illustrated in the drawing, an air flow blown off from an air conditioner and sucked into a rack (see (1) in FIG. 14), an air flow blown off from the air conditioner and sucked into the air conditioner (see (2) in FIG. 14), an air flow exhausted from the rack and sucked into the air conditioner (see (3) in FIG. 14) and an air flow exhausted from the rack and sucked into the rack (see (4) in FIG. 14) are observed as air flows in the data center.
In the case that a flow rate of air exhausted from a rack and sucked into the rack is higher than a predetermined rate, a hot spot is generated with air exhausted from electronic equipment and flowing around the rack. On the other hand, in the case that a flow rate of air blown off from an air conditioner is lower than another predetermined rate, electronic equipment mounted on a lower part of a rack is cooled, but electronic equipment mounted on an upper part of the rack is not cooled for lack of cooled air and hence a hot spot is generated at the upper part of the rack as illustrated in FIG. 15.
Here, an example illustrated in FIG. 15 will be specifically described. In FIG. 15, there are two racks on the raised-floor level. An air flow rate in the upper space of the each rack is 10 m³/min. An air flow rate in the lower space of the each rack is 150 m³/min. The total air flow rate in the rack is 320 m³/min (corresponding to about 59 kW). An air conditioner 20 blows off cooled air at the air flow rate of 300 m³/min and at the constant temperature of 20° C.
As illustrated in FIG. 15, air cooled down to 20° C. exhausted to a bottom-floor level and passing through a panel is supplied to each rack on which the electronic equipment is mounted. In the situation, the cooled air is supplied to pieces of electronic equipment starting from those mounted on a lower shelf of each rack, so that a variation in temperature occurs between upper and lower shelves of the rack. As a result, re-circulation of exhaust air occurs in the electronic equipment stacked on the upper shelf of the rack for lack of the cooled air and the hot spot is generated.
Therefore, as a method of preventing a hot spot from being generated, there is known a technique for causing a flow rate of air sucked into electronic equipment to be higher than a flow rate of air blown off from an air conditioner. For example, cold air is mixed with exhaust air on a raised-floor level that is the space in contact with a surface of an air conditioner suction port, thereby causing the flow rate of air sucked into the electronic equipment to be higher than the flow rate of air blown off from the air conditioner. Japanese Laid-open Patent Publication No. 08-303815 discloses an example of such technique.
However, the above mentioned technique for increasing the flow rate of air sucked into the electronic equipment has such a problem that, since the cold air is mixed with the exhaust air on the raised-floor level that is the space in contact with the surface of the air conditioner suction port, part of the air blown off from the bottom-floor level toward the raised-floor level is not supplied to the electronic equipment and directly returns to the air conditioner suction port and hence the energy of the air is not effectively utilized.

SUMMARY

According to an aspect of the invention, an installation for cooling an electronic device provided on a floor in a room includes an underfloor space below the floor; an air conditioner for sending air to the underfloor space; a first opening provided in the floor and adjacent to the electronic device, for sending air from the underfloor space to the room; and a second opening provided in the floor and adjacent to the air conditioner, the second opening being configured to cause the air pressure of the lower side of the second opening to be lower than the air pressure of the upper side of the second opening.
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

FIG. 1 is a block diagram illustrating a configuration of an air conditioning installation according to an embodiment 1;

FIG. 2 is a diagram illustrating detailed configurations of an opening part and an air conditioner;

FIG. 3 is a diagram illustrating a rack cooling operation;

FIG. 4 is a diagram illustrating an upper surface of a data center to which the air conditioning installation according to the embodiment 1 is applied;

FIG. 5 is a diagram illustrating a side surface of the data center to which the air conditioning installation according to the embodiment 1 is applied;

FIG. 6 is a perspective view of the data center to which the air conditioning installation according to the embodiment 1 is applied;

FIG. 7 is a diagram illustrating one example of a result of simulation performed;

FIG. 8 is a diagram illustrating another example of the result of simulation performed;

FIG. 9 is a diagram illustrating an example of a result of simulation performed;

FIG. 10 illustrates diagrams of examples of pressure distributions;

FIG. 11 is a diagram illustrating an example of a location of an opening part;

FIG. 12 is a diagram illustrating an example of a result of simulation performed;

FIG. 13 is a block diagram illustrating a configuration of an air conditioning installation according to an embodiment 2;

FIG. 14 is a diagram illustrating a flow of air in an air conditioning installation;

FIG. 15 is a diagram illustrating an existing rack cooling operation; and

FIG. 16 is a block diagram illustrating a configuration of an air conditioning installation according to an embodiment 3.

DESCRIPTION OF EMBODIMENTS

Next, preferred embodiments of an air conditioning installation according to the present invention will be described in detail with reference to the accompanying drawings.

Embodiment 1

In the following, a configuration of an air conditioning installation according to the embodiment 1 and a flow of processing performed will be described in this order and finally, advantages attained by the embodiment 1 will be described.
[Configuration of Air Conditioning System]
Next, a configuration of an air conditioning installation 100 will be described with reference to FIG. 1. FIG. 1 is a block diagram illustrating the configuration of the air conditioning installation according to the embodiment 1. As illustrated in FIG. 1, the air conditioning installation 100 has a double-floor configuration including a raised-floor level 1 a and a bottom-floor level 1 b and is configured such that an air conditioner 20 sends cooled air down to the bottom-floor level 1 b and then supplies the cooled air to electronic equipment 40 a disposed on the raised-floor level 1 a. In general, a raised-floor opening panel through which the cooled air is supplied to the electronic equipment 40 a is disposed adjacent to the electronic equipment in order to prevent the cooled air from being mixed with exhaust hot air. Next, the respective components of the air conditioning installation will be described.
An opening part 10 which is provided separately from the raised-floor opening panel which is disposed adjacent to the electronic equipment in order to supply the cooled air to the electronic equipment is formed in a raised tiled floor 31 which is in contact with a negative pressure area which is an area in the bottom-floor level 1 b and on which a negative pressure is exerted relative to a positive pressure on the raised-floor level 1 a in order to take exhaust hot air into the bottom-floor level 1 b from the raised-floor level 1 a.
The air conditioner 20 includes a blower 21 for sending air to the bottom-floor level 1 b and an heat exchanger 24 for cooling the hot air which is exhausted from the electronic equipment 40 a and operates to send the cooled air down to the bottom-floor level 1 b using the blower 21 and supply the cooled air up to the electronic equipment 40 a disposed on the raised-floor level 1 a through a raised-floor opening panel 50.
Next, detailed configurations of the opening part 10 and the air conditioner 20 will be described with reference to FIG. 2. FIG. 2 is a diagram illustrating detailed configurations of the opening part and the air conditioner. As illustrated in FIG. 2, the opening part 10 is fitted in a raised tiled floor 31 in contact with the negative pressure area in the vicinity of the air conditioner.
The air conditioner 20 includes the blower 21, an air conditioner suction port 23 and the heat exchanger 24. The blower 21 is driven using a built-in motor 21 a to send the cooled air down to the bottom-floor level 1 b through an air conditioner blow-off port.
The heat exchanger 24 cools the exhaust hot air which is exhausted from the electronic equipment 40 a and is sucked into the heat exchanger through the air conditioner suction port 23 and makes the blower 21 blow off the cooled air.
Next, a rack cooling operation will be described in detail with reference to FIG. 3. FIG. 3 is a diagram illustrating the rack cooling operation. In FIG. 3, the two racks in which a total air flow rate is 320 m³/min (corresponding to about 59 kW) are cooled. (An air flow rate of the each rack is 160 m³/min.) The air conditioner 20 blows off air which has been cooled down to the constant temperature of 20° C. at the air flow rate of 300 m³/min.
As illustrated in the drawing, the air which has been cooled down to 20° C. using the air conditioner 20 and blown off at the air flow rate of 300 m³/min using the blower is mixed with exhaust hot air which has been taken into the opening part 10 in a heated-up-to-30° C. and decelerated-down-to-20 m³/min state and then the mixed air is blown off toward the raised-floor level at the total air flow rate of 320 m³/min.
That is, in the air conditioning installation 100, although the exhaust hot air from the electronic equipment is taken into the system and hence the average temperature of the cooled air which is mixed with the exhaust hot air in a vacant bottom-floor level is increased, the air flow rate of the cooled air may be increased. As a result, it may become possible to prevent the temperature on a rack air-suction surface from being varied, thereby preventing a hot spot from being generated.
Returning to the description on the configuration in FIG. 1, the electronic equipment 40 a is mounted on a rack 40 disposed on the raised tiled floor 31, the cooled air is supplied to the electronic equipment 40 a using the air conditioner 20 and the electronic equipment 40 a then exhausts the hot air to the raised-floor level 1 a.
The raised-floor opening panel 50 is an opening panel which is fitted in the raised tiled floor in the vicinity of the rack 40 in order to supply the cooled air which has been sent down to the bottom-floor level 1 b up to the raised-floor level 1 a.
Next, results of simulation performed by modeling a data center to which the air conditioning installation 100 according to the embodiment 1 is applied and using a height from a bottom floor, an air flow rate of the air conditioner and an area of a blow-off opening part in the air conditioner as parameters will be described with reference to FIGS. 4 to 12. First, the data center to which the air conditioning installation which is a simulation object is applied will be described with reference to FIGS. 4 to 6. FIG. 4 is a diagram illustrating an upper surface of the data center to which the air conditioning installation according to the embodiment 1 is applied. FIG. 5 is a diagram illustrating a side surface of the data center to which the air conditioning installation according to the embodiment 1 is applied. FIG. 6 is a perspective view of the data center to which the air conditioning installation according to the embodiment 1 is applied.
As illustrated in FIGS. 4 to 6, the data center as the simulation object is modeled to have the room size of 7.2 [m]×10.8 [m] (W×D), have a height from a raised floor of 2.5 [m], have the size of a raised-floor opening panel 50 of 0.6 [m]×0.6 [m] (W×D) whose aperture ratio is 50% and have the area of the opening part 10 of 0.8 [m]×0.6 [m] (W×D).
First, as a simulating process, how the value of a maximum vertical distance “d” [m] (hereinafter, referred to as a negative pressure distance) measured from a front surface of the air conditioner is changed within a range of the negative pressure area on which a negative pressure is exerted relative to a positive pressure on the raised-floor level in the case that the parameters (the height from the bottom floor and the air conditioner air flow rate) have been changed has been confirmed.
Results of simulation performed are illustrated in FIGS. 7 to 9. FIGS. 7 to 9 are diagrams illustrating examples of results of simulation performed in order to confirm a change in the value of the negative pressure distance “d” which is obtained when the height from the bottom floor has been changed. As illustrated in FIGS. 7 and 8, according to the result of simulation performed, the lower the bottom floor is, the more the value of the negative pressure distance “d” is increased.
An example illustrated in FIG. 9 is of a result of simulation performed in order to confirm a change in the value of the negative pressure distance “d” obtained when the air conditioner air flow rate has been changed. As illustrated in FIG. 9, the more the air conditioner air flow rate is increased, the more the value of the negative pressure distance “d” is increased.
Next, pressure distributions under the raised floor will be described with reference to FIG. 10. FIG. 10 illustrates diagrams explaining the pressure distributions. As illustrated in FIG. 10, a change in the negative pressure distance “d” and a change in the pressure distribution at the height of −0.04 [m] measured from the raised floor obtained when the height from the bottom floor has been changed are indicated. In the examples in FIG. 10, a black part indicates a negative pressure area which is the area within the bottom-floor level and on which a negative pressure is exerted relative to a positive pressure on the raised-floor level. As illustrated in the examples in FIG. 10, the higher the height from the bottom floor is, the more the negative pressure distance “d” is decreased.
In addition, as illustrated in FIG. 10, in the case that the height from the bottom floor is h=0.9, a negative pressure area is not observed on the side where the electronic equipment is disposed relative to the air conditioner and a negative pressure area is observed on the side opposite to the side where the electronic equipment is disposed relative to the air conditioner. In a data center of the above mentioned arrangement, an opening part may be provided on the side opposite to the side where the electronic equipment is disposed relative to the air conditioner. That is, the location of the opening part suited for conditions of a data center concerned may be determined on the basis of the results of simulation performed in the above mentioned manner.
In addition, negative pressure area may also be caused by the flow rate of the air below the opening part being higher than that above the opening part.
Next, an air flow rate increasing effect which has been clarified from a result of simulation performed by modeling a data center to which the air conditioning installation 100 according to the embodiment 1 is applied such that the raised-floor opening panel 50 is disposed in an area corresponding the raised floor on which a negative pressure is exerted relative to a pressure on a raised-floor level will be described with reference to FIGS. 11 and 12. In the examples illustrated in FIGS. 11 and 12, it is assumed that simulation has been performed in a state in which the air flow rate of the air conditioner has been set to 4.0 [m³/s] and the air blow-off temperature thereof has been set to 20° C. FIG. 11 is a diagram illustrating an example indicative of the location of the opening part and FIG. 12 is a diagram illustrating the result of simulation performed.
As illustrated in FIG. 11, the data center which is the simulation object is modeled such that the opening part is disposed in a negative pressure area in the vicinity of the air conditioner. Identification numbers (corresponding to Grill Nos. in FIG. 12) 1 to 20 are allocated to respective raised-floor opening panels of the data center.
The result of simulation performed on the data center so configured is illustrated in FIG. 12. In the example illustrated in FIG. 12, the air flow rates of the opening part 10 and the respective raised-floor opening panels 50 and the air bow-off temperatures of the opening part 10 and the respective raised-floor opening panels 50 are indicated as the result of simulation performed.
Specifically, “Grill No.” indicative of the identification number of each grill, “Air Flow” indicative of the air flow rate at which air has been blown off from each grill and “Temperature” indicative of the temperature of each blown-off air are indicated in a one-to-one correspondence.
As illustrated in the example in FIG. 12, in the data center to which the air conditioning installation 100 according to the embodiment 1 is applied, an increase in the air flow rate of 0.87 [m³/s] is attained for the air flow rate of 4.0 [m³/s] of the air conditioner. In addition, in the data center to which the air conditioning installation according to the embodiment 1 is applied, as for the temperature of the air which has been blown off from each grill, an increase in the temperature is limited to a value from 0.95 to 1.13° C. for the air blown-off temperature of 20° C. at which the air is blown off from the air conditioner.

Effect of Embodiment 1

As described above, in the air conditioning installation 100 according to the embodiment 1, since the opening part 10 is formed on the level in contact with the negative pressure area in order to take exhaust hot air into the bottom-floor level from the raised-floor level, generation of a hot spot with the exhaust air flowing around a rack, which would occur at an insufficient air flow rate, may be prevented by taking the exhaust hot air into the bottom-floor level from the raised-floor level so as to increase the air flow rate.

Embodiment 2

Although a case in which the opening is usually opened has been described in the explanation of the embodiment 1, the present invention is not limited thereto and may be embodied to control opening/closing of the opening part.
Therefore, in the embodiment 2 which will be described hereinbelow, a configuration of an air conditioning installation according to the embodiment 2 will be described with reference to FIG. 13 in relation to a case in which the direction of air passing through an opening part is sensed to control opening/closing of the opening part in accordance with the direction of the air passing through the opening part, by way of example. FIG. 13 is a block diagram illustrating the configuration of the air conditioning installation according to the embodiment 2.
As illustrated in FIG. 13, an air conditioning installation 100 a according to the embodiment 2 differs from the air conditioning installation 100 according to the embodiment 1 in that an air direction and air speed sensor 60 and an opening panel control section 70 are newly provided. The opening part 10 is configured to be variably opened/closed and opening/closing of the opening part 10 is controlled using the opening panel control section 70 which will be described later. For example, the opening part 10 has a valve 10 a. The opening panel control section 70 controls the valve 10 a so as to control opening/closing of the opening part 10. The opening panel control section 70 enlarges the opening part 10 when it detects the direction of air from the raised-floor level to the bottom-floor level. The opening panel control section 70 reduces the opening part 10 when it detects the direction of air from the bottom-floor level to the raised-floor level.
The air direction and air speed sensor 60 senses the direction of the air passing through the opening part 10 which is configured to be variably opened/closed in order to take exhaust hot air into the space under the raised floor. Then, the air direction and air speed sensor 60 notifies the opening panel control section 70 of a result of sensing.
In the case that it has been sensed that the air is directed from the raised-floor level toward the bottom-floor level, the opening panel control section 70 controls to open the opening part 10 which is configured to be variably opened/closed in order to take the exhaust hot air into the bottom-floor level. While in the case that it has been sensed that the air is directed from the bottom-floor level toward the raised-floor level using the air direction and air speed sensor 60, the opening panel control section 70 controls to close the opening part 10.
As described above, in the embodiment 2, the air conditioning installation 100 a senses the direction of the air passing through the opening part 10 using the air direction and air speed sensor 60. Then, in the case that it has been sensed that the air is directed from the raised-floor level toward the bottom-floor level using the air direction and air speed sensor 60, the air conditioning installation 100 a controls to pen the opening part 10 which is configured to be variably opened/closed in order to take the exhaust hot air into the bottom-floor level using the opening panel control section 70. While in the case that it has been sensed that the air is directed from the bottom-floor level toward the raised-floor level using the air direction and air speed sensor 60, the air conditioning installation 100 a controls to close the opening part 10 using the opening panel control section 70. Therefore, in the case that it has been sensed that the air is directed from the bottom-floor level toward the raised-floor level, the opening part 10 which is configured to be variably opened/closed in order to take the exhaust hot air into the bottom-floor level may be closed to prevent the cooled air from being mixed with the exhaust hot air on the raised-floor level.

Embodiment 3

Although the embodiments have been described, the present invention is not limited to the above mentioned embodiments and may be embodied in a variety of ways. Thus, in the following, a further embodiment of the present invention will be described as an embodiment 3.
(1) Opening/Closing the Opening Part in Accordance with Pressure Information
In the above mentioned embodiment 2, a case in which the direction of the air passing through the opening part is sensed to control opening/closing of the opening part in accordance with the direction of the air passing through the opening part has been described. However, the embodiment is not limited thereto and the embodiment may be configured to sense bottom-floor-level pressure information (information on pressure exerted on a bottom-floor level) of the opening part is sensed to control opening/closing of the opening part in accordance with the bottom-floor-level pressure information of the opening part.
FIG. 16 is a block diagram illustrating the configuration of the air conditioning installation according to the embodiment 3. Specifically, the air conditioning installation 100 a includes a bottom-floor-level pressure sensor 80 for sensing the bottom-floor-level pressure information of the opening part 10 and an opening panel control section 70 for controlling opening/closing of the opening part 10 in accordance with the bottom-floor-level pressure information of the opening part 10. Then, in the case that bottom-floor-level pressure information sensed using the bottom-floor-level pressure sensor 80 is of a value less than a predetermined threshold value, the opening panel control section 70 of the air conditioning installation controls to open the opening part 10 which is configured to be variably opened/closed in order to take the exhaust hot air into the bottom-floor level. While in the case the bottom-floor-level pressure information sensed using the bottom-floor-level pressure sensor 80 is of a value more than the predetermined threshold value, it controls to close the opening part 10.
As described above, according to the embodiment 3, in the case that the bottom-floor-level pressure information of the opening part 10 which is configured to be variably opened/closed in order to take the exhaust hot air into the bottom-floor level and the sensed bottom-floor-level pressure information is of a value less than the predetermined threshold value, the air conditioning installation 100 a controls to open the opening part 10. While in the case that the bottom-floor-level pressure information is of a value more than the predetermined threshold value, the system 100 a controls to close the opening part 10. Thus, in the case that the bottom-floor-level pressure information is of a value more than the predetermined threshold value, the opening part 10 may be closed to prevent the cooled air from being mixed with the exhaust air on the raised floor level.
A system according to the above embodiments exhibit such an advantage that the hot spot at a rack generated with exhaust air flowing around the rack, which occurs at an insufficient air flow rate, can be efficiently prevented by supplying the exhaust hot air to the bottom-floor level from the raised-floor level to increase the air flow rate.
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 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.

Claims

1. An installation for cooling an electronic device provided on a floor in a room, comprising:

an underfloor space below the floor;

an air conditioner for sending air to the underfloor space;

a first opening provided in the floor and adjacent to the electronic device, for sending air from the underfloor space to the room; and

a second opening provided in the floor and adjacent to the air conditioner, the second opening being configured to cause the air pressure of the lower side of the second opening to be lower than the air pressure of the upper side of the second opening.

2. The installation according to claim 1, wherein the second opening is openable and closable, the installation further comprising:

a sensor for detecting a direction of air getting through the second opening; and

a controller for enlarging the second opening when the sensor detects the direction of air from the room to the underfloor space, and reducing the second opening when the sensor detects the direction of air from the underfloor to the room.

3. The installation according to claim 1, wherein the second opening is openable and closable, the installation further comprising:

a sensor for detecting a pressure under the second opening in the underfloor space; and

a controller for enlarging the second opening when the sensor detects the pressure lower than a predetermined value, and reducing the second opening when the sensor detects the pressure equal to or higher than the predetermined value.

4. The installation according to claim 1, wherein the air conditioner includes an air outlet for blowing air, the second opening being adjacent to the air outlet.

5. The installation according to claim 1, wherein the flow rate of the air below the second opening is higher than that above the second opening.