JP5982242B2 - Local air conditioning system for data centers - Google Patents

Description

  The present invention relates to a local air-conditioning system capable of appropriately cooling heat generated from a server in a data center in which a plurality of server racks are arranged, for example, IT (Information Technology) equipment, for example, a plurality of servers.

  Conventionally, in a data center where a plurality of server racks storing a plurality of servers using natural ventilation are arranged, an air conditioner is provided in an area required for the server racks and exhausted from the plurality of servers. The large number of servers are cooled by sucking warm air and sending out cool air cooled by a heat exchanger. In these air conditioners, as described in Patent Document 1, the temperature on the front side and the back side of the server rack is measured, and these measurement results are reflected in the air conditioner to control the air conditioner. Yes.

  On the other hand, as shown in FIG. 10, the conventional server rack has a rack main body 71 partitioned by a plurality of partition plates 72 to form a plurality of server accommodation chambers 73. Each server 79 is accommodated in the server accommodation chamber 73. The front surface of the rack main body 71 is open on the entire surface, and this serves as an intake port 74 and communicates with each server accommodation chamber 73. The entire rear surface of the rack body 71 is also opened, and this serves as an exhaust port 75 to be exhausted from each server accommodation chamber 73. The floor 77 on which the rack body 71 is placed is formed in a double floor structure, and an air supply plenum 76 is formed under the floor. The floor 77 is provided with a grating 78, and the cold air from the air conditioner 81 (see FIG. 11) passes through the air supply plenum 76 and is a grating plate that is a lattice plate formed on the floor 77 near the air inlet 74 of the rack body 71. Air is supplied from 78 and flows into the air inlet 74 of the rack body 71. This inflow of cold air is performed by being sucked in by a built-in fan 80 built in the server 79.

  As shown in FIG. 11, the conventional data center has a plurality of rack rows 82 (four rows in the figure) formed by arranging a plurality (six in the figure) of rack bodies 71 containing servers 79 in the server management room 83. ) Arranged. The gratings 78 provided on the floor 77 are all formed on the intake port 74 side of the rack body 71. When the server 79 operates and generates heat, as described above, the cold air is supplied from the air conditioner 81 through the air supply plenum 76 into the server management room 83 from the grating 78, and the server accommodation rooms 73 ( 10), the server 79 is cooled and the warmed warm air is exhausted from the exhaust port 75 to the server management room 83 and returned to the air conditioner 81 again.

  However, there are many users of the server 79 managed in the data center, and the server 79 used varies depending on the situation. Therefore, in any location in the server management room 83, in any range, in any amount, any amount of heat is generated, and the heat environment is indefinite. In order to manage each server 79 that has become high temperature under such a temperature environment at an appropriate temperature, the air volume from the air conditioner 81 is increased. However, when the amount of air taken in increases and the flow velocity increases, the intake air is attracted by the intake air, and warmed exhaust gas goes around the rack body 71 (arrow A in FIG. 10). If such exhaust (warm air) is taken into the server again, the server is not properly cooled, causing a malfunction in the operation of the server.

  In order to solve such a point, the server rack of patent document 2 was developed. This is composed of a rack body having an intake port and an exhaust port, and a plurality of server accommodation chambers partitioned by a partition plate are formed in the rack body, and the exhaust port accommodates in the server accommodation chamber. Equipped with a fan that can blow a larger air volume than the built-in fan included in the installed server, or a device that introduces exhaust into the exhaust plenum so that warm exhaust from the exhaust port does not enter the intake port side Yes.

JP 2012-33105 A JP 2009-140421 A

  However, as in the above-mentioned Patent Document 1, it is an optimal control method in terms of efficiency to individually correspond to an air conditioning unit to a server rack, but when considering control and cost in various data centers, it is considered. There seems to be room for this. It is more rational to control a specific number of server racks and a specific number of air conditioning units in an integrated manner than to control a server rack containing multiple servers and the air conditioning units corresponding to these server racks on a one-to-one basis. This may lead to cost reduction.

  Moreover, the thing of the said patent document 2 requires various apparatuses and installations, such as providing a large sized fan, an exhaust duct, and an exhaust plenum, and will become large-scale and will also become expensive.

  The present invention takes the above-described conventional technology into consideration, and controls a plurality of server racks storing a plurality of servers and these air conditioning units in an integrated manner, thereby effectively sucking warm air discharged from the servers. Thus, the present invention provides a local air conditioning system for a data center that does not go into the front of these servers and that can supply cool air for server cooling into the servers efficiently and reliably.

In the invention of claim 1 of the present application, a space in which a plurality of IT devices and a plurality of air conditioners are installed corresponding to the IT devices, and the height of the IT device is the lower part of the space above the IT device. In a data center in which a vertical temperature distribution is formed as a two-layer structure with the air conditioning unit located at the upper part of the space, the plurality of IT devices and the plurality of air conditioning units provided corresponding to these IT devices Among them, some IT devices and air conditioners corresponding to them are regarded as one body, and when exhausting heat of the IT devices, two or more non-adjacent air conditioners are operated and the following stratification efficiency (E ), And (E _MAX ) are local air conditioning systems for data centers that are controlled to be close to 1, respectively.

  In the invention of claim 2, the two or more air conditioners are the local air conditioning system for a data center according to claim 1 located at both ends.

According to a third aspect of the present invention, the local air conditioning system for a data center according to any one of the first or second aspect, wherein the air conditioner in operation blows out cold air horizontally.

  According to the first and second aspects of the present invention, a plurality of IT devices and a plurality of air conditioners are collectively controlled as one set, and the warm air exhausted from the IT devices is effectively sucked to front the IT devices. And cool air for cooling IT equipment can be efficiently and reliably supplied into the server. As a result, the cooling time is extended by increasing the stratification efficiency, which can greatly contribute to the energy saving of the data center.

Further, according to the inventions of claims 2 and 3, the stratification efficiency (E), (E _max ) can be brought closer to 1 more effectively, and the stratification efficiency (E _max ) can be further increased. It can be done.

It is explanatory drawing of the 2 layer block model of Example 1 of this invention. It is a figure which shows the image of having installed the air conditioner above each said server rack in the data center of Example 1 of this invention corresponding to six server racks. It is an isotherm diagram of Case2-1-c in the experiment of Example 1 of the present invention. It is an isotherm diagram of Case2-1-d in the experiment of Example 1 of the present invention. It is an isotherm diagram of Case3-1 in the experiment of Example 1 of the present invention. It is an isotherm diagram of Case3-2 in the experiment of Example 1 of the present invention. It is an isotherm of Case1-a in the experiment of Example 1 of the present invention. It is an isotherm diagram of Case4-3 in the experiment of Example 1 of the present invention. It is the graph which compared the stratification efficiency of each Case in experiment of Example 1 of this invention. It is sectional drawing of the conventional server rack. It is a schematic plan view of the conventional data center.

A space where a plurality of IT devices and a plurality of air conditioners are installed corresponding to the IT devices, and the air conditioner provided above the IT devices is located with the space up to the height of the IT devices. However, in a data center in which the upper and lower temperature distribution is formed as a two-layer structure with the space as the upper part, among the plurality of IT devices and the plurality of air conditioners provided corresponding to these IT devices, some of the plurality The IT equipment and the air conditioners corresponding to them are integrated, and when the heat exhausted from the IT equipment, the two or more non-adjacent air conditioners are operated and the following stratification efficiency (E), (E _MAX ) Each was controlled to be close to 1.

  As a result, the cool air for cooling the IT equipment can be supplied into the server efficiently and reliably.

  A first embodiment of the present invention will be described. As shown in FIG. 1, it is an appropriate evaluation method to evaluate the energy saving of a data center of IT equipment such as a server combined with natural ventilation by using a two-layer block model. In addition, by increasing the stratification efficiency described later, the cooling time by natural ventilation can be extended, which contributes to energy saving of the data center. The two-layer block model shown in FIG. 1 refers to the lower part of the space (Lower Zone) up to the height of the IT equipment, and the upper part (Upper Zone) where the air conditioner provided above the IT equipment is located. The space where the vertical temperature distribution is formed.

  First, in order to evaluate the degree of influence on the IT equipment suction temperature due to the recursion of the cooling efficiency and the exhaust heat of the IT equipment itself in the data center where the natural ventilation method was introduced, the present inventor is based on the heat balance as follows. The evaluation model shown was created. Generally, natural ventilation (q) is less than IT equipment airflow (Q) due to an increase in IT equipment airflow with high load type.

The intake temperature (θs) of IT equipment, which is important in the operation of the thermal environment of the data center, is affected by the exhaust temperature (θ _E ). Here, between theta _E and [theta] s of air assume that there is an air flow with a mixed air volume (V), it is important to suppress the V in order to maintain a low [theta] s. In this evaluation model, the stratification efficiency (E) as shown in the following formula (1) was defined as an index representing the indoor air flow in the vertical direction. Further, the value based on θs and max was defined as the stratification efficiency (E _max ) shown in Formula (2).

The stratification efficiencies (E) and (E _max ) are generally in the range of 0 <E <1, and the stratification efficiencies (E) and (E _max ) are 1 when the mixed air volume of the room air in the vertical direction is small. It can be seen that a vertical temperature distribution is formed, indicating that the cooling efficiency is high. Therefore, it was found that the stratification efficiency (E) is an important index for evaluating and examining the cooling effect of IT equipment in a natural ventilation combined data center.

  A case study using a computer was conducted in order to examine what mode of air conditioning would be reasonable when partial air conditioning was needed to compensate for the lack of cooling with natural ventilation. As shown in FIG. 2, when six air conditioners 2 (empty 1 to empty 6) are respectively arranged facing the six rows of server racks 1 (containing a plurality of servers inside), A case was assumed in which each air conditioner 2 (sky 1 to sky 6) performs 50% partial air conditioning. Table 1 shows the study cases.

  Cases (Case1-a, Case1-b) in which all IT devices (here, servers, the same applies hereinafter) are air-conditioned evenly with a load removal rate of 50%, and the air conditioning balance is 75% and 25% for each server rack Cases with two stages (Case 2-1-a, Case 2-1-b, Case 2-1-c, Case 2-1-d, Case 2-2), 100% air-conditioning and non-air-conditioning cases (Case 3-1, Cases 3-2) and cases (Case 4-1, Case 4-2, Case 4-3, Case 5-1, Case 5-2) in which overcooling exceeding 100% was performed only on some air conditioners were prepared. In Table 1, arrows next to the numbers (horizontal: →, vertical: ↑) indicate the blowing direction of the air conditioner.

The isotherm of the representative cross section of these cases is shown in FIGS. 3 to 8, and the comparison of the stratification efficiency is shown in FIG. First, looking at Case 1-a and Case 1-b, which are air-conditioned equally by all air conditioners, as shown in FIG. 9, in Case 1-a, the stratification efficiency (E) is 0.51, and the stratification efficiency (E _MAX) is In Case 1-b, the stratification efficiency (E) was 0.49 and the stratification efficiency (E _MAX) was 0.4, which was smaller than other cases described later. As a result, it was found that in the partial air conditioning mode, it is not a good idea to air-condition all server racks equally by all air conditioners.

  Next, the direction of blowing was examined in Case 2. Looking at Case 2-1-c and Case 2-1-d, as shown in FIGS. 3 and 4, the exhaust of the server with low load removal rate (see Table 1, right side 3) in FIG. It was found that the (three on the left side) exhaust was blown horizontally and the isotherm was lower than that of FIG. From these things, in the conditions of Cases 3, 4 and 5, the blowout of the air conditioner is horizontal.

Next, the arrangement of air conditioners was examined. Looking at Case 3-1 and Case 3-2, Case 3-1 operates only the air conditioner on the left (see Table 1, Sky 1, 2 and 3), whereas Case 3-2 has every other one. Only air conditioners (sky 1, 3, and 5) are operated. As a result, as shown in FIGS. 5 and 6, it was found that clean temperature stratification was formed in the case where the air conditioners were arranged in a distributed manner rather than the case where the air conditioners were arranged in a concentrated manner. Looking at these stratification efficiency, as shown in FIG. 9, stratification efficiency Case3-1 (E) is 0.89, stratified efficiency _{(E MAX)} is 0.74, the Case3-2 The stratification efficiency (E) was 0.91, the stratification efficiency (E _MAX ) was 0.83, and the stratification efficiency (E _MAX ) could be increased by the dispersed arrangement.

The capacity of the air conditioner was also examined. Looking at Case 1-a and Case 4-3, Case 1-a is one in which all air conditioners (empty 1 to 6) are operated at 50% as described above, and Case 4-3 is an air conditioner at both left and right ends. Although only the (empty 1, 6) was operated, it was found from FIGS. 7 and 8 that a clearer temperature stratification was formed in FIG. 8 showing Case 4-3. Referring to FIG. 9, the stratification efficiency (E) of Case 1-a is 0.51, the stratification efficiency (E _MAX ) is 0.36, and the stratification efficiency (E) of Case 4-3 is 0.97, the stratification efficiency (E _MAX ) is 0.92, and the stratification efficiency (E _MAX ) is maintained at a higher value when intensive cooling is performed by some air conditioners. It was.

From these, the experimental results using the stratification efficiency (E) and (E _MAX ), which are evaluation models created by the present inventors, are effective, and the stratification efficiency (E) and (E _MAX ) Since the cooling time by natural ventilation is increased by increasing the size, it greatly contributes to the energy saving of the data center.

In the partial air conditioning of the data center combined with the natural ventilation, it has been found that it is effective for maintaining the temperature stratification to disperse and arrange the air conditioners that are overcooled in the data center. It was also found that the stratification efficiency (E _MAX ) is higher when the exhaust of the server with a low load removal rate is blown out vertically and the exhaust of the high server is blown out horizontally.

  In the above embodiment, the server is described as the IT device. However, other IT devices may be used as long as they are arranged in the data center, and storage or UPS (Uninterruptible Power Supply) may be used.

  1 server rack, 2 air conditioner

Claims (3)

A space where a plurality of IT devices and a plurality of air conditioners are installed corresponding to the IT devices, and the air conditioner provided above the IT devices is located with the space up to the height of the IT devices. However, in the data center where the upper and lower temperature distribution is formed as a two-layer structure with the space as the upper part,
Among the plurality of IT devices and the plurality of air conditioners provided corresponding to each of these IT devices, some of the IT devices and the corresponding air conditioners are regarded as a unit, and the exhaust heat of the IT devices is integrated. At this time, a local air conditioning system for a data center is characterized in that two or more air conditioners that are not adjacent to each other are operated to control the stratification efficiency (E) and (E _MAX ) to be close to 1, respectively.
The local air conditioning system for a data center according to claim 1, wherein the two or more air conditioners are located at both ends. The local air conditioning system for a data center according to any one of claims 1 and 2 , wherein the air conditioner in operation blows cold air horizontally.