Server rack exhaust airflow adjustment device

Abstract

To reduce influence of exhaust of a server rack on surroundings and suppress temperature rise of air supplied to the server rack, to save energy with reduction of an air-conditioned air volume.SOLUTION: An exhaust airflow adjustment device 20 is for adjusting an exhaust airflow of a server rack 4, and comprises an airflow adjustment surface 21 arranged facing a rear surface of the server rack 4 at a predetermined distance d. The airflow adjustment surface 21 is formed in any one of shapes of a curved type with a center part in a width direction recessed along a vertical direction relative to the rear surface of the server rack, a flat type made of a flat plate, and a vertical blade type with a plurality of vertically elongated blade members 24 arranged in the width direction at an angle to the rear surface of the server rack.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a device for adjusting exhaust airflow in a server rack. [Background technology]

[0002] Conventionally, one of the common air conditioning methods used in server rooms of data centers is the hot aisle containment method, which encloses the space on the exhaust side of the server rack to prevent high-temperature air from mixing with the intake air (for example, Patent Documents 1 to 3 listed below).

[0003] In this system, server racks, each housing multiple server machines in multiple tiers, are lined up with their fronts facing the backs to form a server rack row, and the space between the server racks, which are spaced apart with their backs facing each other, forms a hot aisle. The high-temperature exhaust air from the multiple server racks is collected in the same hot aisle containment and cooled by an air conditioner. The air supplied to the server racks is conditioned air (air cooled by an air conditioner) supplied to the space (cold aisle) opposite the fronts of the server rack row. The physical separation of the cold aisle and hot aisle prevents the mixing of air of different temperatures between the two spaces, suppressing temperature fluctuations in the conditioned air supplied to the server racks and enabling efficient heat treatment.

[0004] In recent years, new data centers are being built with plans to install ultra-high load racks of around 20-30kW per server rack, raising concerns about the occurrence of localized heat pools. One technology that can solve this problem is to optimize the airflow around the server racks by adjusting the direction of the exhaust airflow from the server racks.

[0005] For example, Patent Document 4 below discloses a wind direction changing member that changes the direction of cooling air in an underfloor air duct for a server cooling system, which has two fixed legs and has a wind direction changing panel and an obstacle avoidance section between the two fixed legs.

[0006] Furthermore, Patent Document 5 below discloses an airflow control plate having an inclined portion that protrudes diagonally upward from a server rack and a side portion formed between the side end of the inclined portion and the server rack, wherein the inclined portion has a predetermined inclination angle. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-55691 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-72697 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-140421 [Patent Document 4] Patent No. 7112144 [Patent Document 5] Japanese Patent Application Laid-Open No. 2014-219862 Summary of the Invention [Problem to be solved by the invention]

[0008] In the hot aisle containment system mentioned above, if the operating load of each server rack becomes uneven, the exhaust air from a server rack with a large heat output and exhaust air volume (hereinafter referred to as a "high-load server rack") will pass through a server rack with a small heat output and exhaust air volume (hereinafter referred to as a "low-load server rack") placed back-to-back facing it, or an inactive server rack, and reach the cold aisle. This causes the supply air temperature to the server rack to rise and localized heat accumulation, resulting in problems such as reduced air conditioning efficiency and adverse effects on the server machines due to temperature increases.

[0009] One possible solution to this problem would be to increase the distance between rows of server racks that are back to back, or to not place rows of server racks facing each other. However, this would increase the installation area required per server rack and reduce the number of server racks that can be installed in a server room, making this inefficient.

[0010] The airflow direction changing member described in Patent Document 4 above is intended to change the direction of the intake airflow for cooling under the floor in a server room with a floor-air outlet system, and is not intended to reduce the impact on the server racks by controlling the exhaust airflow discharged from the server racks.

[0011] Furthermore, as a means for adjusting the direction of exhaust airflow from a server rack, a conventional method has been known in which multiple airflow control plates are attached directly to the rear of the server rack in the vertical direction, as described in Patent Document 5. However, when such airflow control plates are attached directly to the rear of the server rack, air resistance increases, reducing the amount of air passing through the server rack and causing the temperature inside the server to rise. In order to maintain the temperature inside the server rack at or below a predetermined level, it is necessary to either lower the temperature of the conditioned air or increase the airflow, both of which pose the problem of increasing the energy consumption associated with air conditioning.

[0012] Therefore, the main objective of the present invention is to provide an exhaust airflow adjustment device for a server rack that reduces the impact of exhaust from the server rack on the surrounding area, suppresses the temperature rise of the air supplied to the server rack, and saves energy by reducing the amount of air required for air conditioning. [Means for solving the problem]

[0013] In order to solve the above problems, the present invention as claimed in claim 1 provides an exhaust airflow adjustment device for adjusting the exhaust airflow of a server rack in a server room provided with a plurality of server rack rows, each row having server machines stored in multiple tiers in the vertical direction, arranged with the front and back facing in the same direction, comprising: The exhaust airflow adjustment device has an airflow adjustment surface that is disposed facing the rear surface of the server rack at a predetermined distance, The airflow adjustment surface is recessed in the vertical direction at the center of the width direction relative to the rear of the server rack. Consisting of curved plates Curved type Or a porous curved mold in which a large number of openings are formed in the curved plate. The exhaust airflow adjustment device for a server rack is characterized by being formed in any one of the shapes above.

[0014] The invention described in claim 1 relates to an exhaust airflow adjustment device that adjusts the exhaust airflow from the server rack, and the exhaust airflow adjustment device has an airflow adjustment surface that is arranged facing the back surface of the server rack at a predetermined distance, and this airflow adjustment surface is recessed in the vertical direction at the center in the width direction relative to the back surface of the server rack. Consisting of curved plates Curved type Or a porous curved mold in which a large number of openings are formed in the curved plate. It is formed in one of the following shapes. Na Airflow adjustment surface By doing so, As will be shown in the experimental results described below, the ventilation flow ratio (the ratio calculated from the sum of the conditioned air volume of the air conditioner / the exhaust air volume of the server machines, defined as a dimensionless number for determining the amount of conditioned air) is highly reduced, minimizing the impact on the high-load server rack itself and the surrounding server racks. As a result, the impact of the exhaust air from the server rack on the surrounding area can be reduced, and the temperature rise of the air supplied to the server rack can be suppressed, resulting in energy savings due to the reduction in the amount of conditioned air.

[0015] In particular, when the curved plate is a porous curved type in which a large number of openings are formed, As will be clear from the experimental results described below, the ventilation flow rate ratio can be further reduced, and the impact on the highly loaded server rack and surrounding server racks can be reduced.

[0016] Claim 2 The present invention provides an exhaust airflow adjustment device for a server rack according to claim 1, wherein the curved airflow adjustment surface has an upper end inclined in a direction away from the server rack.

[0017] The above claims2 In the described invention, the curved airflow adjustment surface is inclined relative to the rear surface of the server rack, and the same effect can be achieved even when the surface is inclined in this way.

[0018] Claim 3 The present invention provides an exhaust airflow adjustment device for a server rack according to claim 1, wherein the exhaust airflow adjustment device is disposed at a distance of 300 to 600 mm from the rear surface of the server rack.

[0019] The above claims 3 The invention described indicates the optimum distance from the rear of the server rack at which the exhaust airflow adjustment device can be effectively used. [Effects of the Invention]

[0020] As detailed above, according to the present invention, the impact of exhaust from the server rack on the surrounding area can be reduced, and the temperature rise of the air supplied to the server rack can be suppressed, thereby achieving energy savings by reducing the amount of air required for air conditioning. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a cross-sectional view showing an air conditioning system of a data center 1 in which an exhaust airflow control device 20 according to the present invention is installed. [Figure 2] FIG. [Figure 3] FIG. 2 is a perspective view showing a curved exhaust airflow control device 20. [Figure 4] 1A, 1B, and 1C show a curved exhaust airflow control device 20, in which (A) is a front view, (B) is a side view, and (C) is a top view. [Figure 5] FIG. 2 is a perspective view showing a flat exhaust airflow control device 20. [Figure 6] 1A, 1B, and 1C show a planar exhaust airflow control device 20, in which (A) is a front view, (B) is a side view, and (C) is a top view. [Figure 7] FIG. 2 is a perspective view showing a vertical blade type exhaust airflow control device 20. [Figure 8]Showing the vertical fin type exhaust air flow adjustment device 20, (A) is a front view, (B) is a side view, and (C) is a top view. [Figure 9] It is a plan view of the laboratory. [Figure 10] It is a cross-sectional view of the laboratory (viewed in the direction of the arrow of the XX-X line in Fig. 9). [Figure 11] It is a graph showing the relationship between the ventilation flow rate ratio κ and the cold aisle rising temperature ΔT. [Figure 12] It is a graph showing the relationship between the ventilation flow rate ratio κ and the supply and exhaust temperature difference ΔTH of the high-load server rack 4b. [Figure 13] It is a graph showing the relationship between the ventilation flow rate ratio κ and the supply and exhaust temperature difference ΔTL of the low-load server rack 4a. [Figure 14] It is a plan view showing the off-the-shelf guide member 50. [Figure 15] It is a side view showing the off-the-shelf product 1. [Figure 16] It is a side view showing the off-the-shelf product 2. [Figure 17] It is a perspective view showing the exhaust air flow adjustment device used in the experiment. [Figure 18] It is a graph showing the experimental results of the planar type. [Figure 19] It is a cross-sectional view of the vertical fin type exhaust air flow adjustment device 20 (viewed in the direction of the XIX-XIX line in Fig. 17(B)). [Figure 20] It is a graph showing the experimental results of the vertical fin type. [Figure 21] It is a top view of the curved surface type exhaust air flow adjustment device 20. [Figure 22] It is a side view showing the curved surface type exhaust air flow adjustment device 20. [Figure 23] It is a graph showing the experimental results of the curved surface type. [Figure 24] It is a graph showing the experimental results of the porous curved surface type. [Figure 25] It is a longitudinal sectional view of the horizontal fin type exhaust air flow adjustment device 51 (viewed in the direction of the XXV-XXV line in Fig. 17(D)). [Figure 26] It is a graph showing the experimental results of the horizontal fin type. [Figure 27]FIG. 2 is a top view of a V-shaped exhaust airflow adjustment device 51. [Figure 28] 10 is a graph showing the results of a V-shaped experiment. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0023] The exhaust airflow adjustment device 20 for a server rack according to the present invention is a device for adjusting the exhaust airflow exhausted from a plurality of server machines 3 arranged in a server room 1 of a data center.

[0024] 1 and 2, the server room 1 is provided with a server rack row 5 in which a plurality of server racks 4, each housing server machines 3 in multiple vertical tiers, are lined up with their front and backs facing one another. The space between the server rack rows 5, with the backs of the racks facing each other at a distance, forms a hot aisle HA that is heated by the exhaust air emitted by the operation of the plurality of server machines 3. The space facing the fronts of the server rack rows 5 forms a cold aisle CA, to which conditioned air is supplied from the air conditioners 2.

[0025] The server machine 3 is an electronic device that has at least a power supply, CPU, and memory inside an enclosure. Since it generates heat when in operation, it is equipped with an exhaust fan inside that exhausts the heat inside the enclosure toward the back, and an air intake on the front that introduces outside air into the enclosure.

[0026] The server rack 4 is a housing having a plurality of shelves formed in the vertical direction, and is configured so that one or more server machines 3 can be housed on each shelf.

[0027] The server rack row 5 is made up of multiple server racks 4 lined up in a row with the front and back facing the same direction. In the server room 1, one or more sets of server rack rows 5 are arranged, each set consisting of two server rack rows 5, 5 arranged back to back facing each other.

[0028] The hot aisle HA is the space between the backs of the server rack rows 5, which are arranged facing each other with a gap between them, and both ends of the space (both ends in the arrangement direction of the server rack rows 5) are separated by partition boards 6 that extend from the floor to the ceiling of the server room 1, and the top of the server rack row 5 is separated by a partition board 6 that extends from the top of the server rack row 5 to the ceiling of the server room 1, so that air from the cold aisle CA flows into the hot aisle HA through the server racks 4, and air from the cold aisle CA cannot enter the hot aisle HA from any other direction.

[0029] The hot aisle HA is provided with an exhaust port 7 for exhausting air from the hot aisle HA. The exhaust port 7 is provided on the ceiling, wall, or floor of the hot aisle HA. The air exhausted from the exhaust port 7 is sent to the air conditioner 2 through a duct installed in the ceiling or the like.

[0030] The cold aisle CA is a space within the outer server room 1 separated by the server rack rows 5 and the partition board 6. An air intake 8 is provided within the cold aisle CA to supply conditioned air cooled by the air conditioner 2. The air intake 8 is provided on a wall, floor, ceiling, or the like of the cold aisle CA. As a general example, as shown in FIG. 2 , the air intake 8 is provided on one of the wall surfaces perpendicular to the arrangement direction of the server rack rows 5, at a position such that the conditioned air blown into the server room 1 flows along the arrangement direction of the server rack rows 5 through the passages facing the front of the server rack rows 5.

[0031] The conditioned air supplied to the cold aisle CA through the air intake 8 passes through the server racks 4, flows into the hot aisle HA, and circulates in an air circulation system that returns to the air conditioner 2 through the exhaust vent 7.

[0032] The server room 1 is also provided with a temperature detector 10 that measures the temperature in the cold aisle CA (the temperature supplied to the server racks 4), a temperature detector 11 that measures the temperature in the hot aisle HA (the temperature after passing through the server racks 4), and a power measurement unit 12 that measures the instantaneous power of the server racks 4. Furthermore, the air conditioner 2 is provided with an air volume detection unit (not shown) that detects the supply volume of conditioned air, and a control device 13 that controls the operation of the air conditioner 2.

[0033] By measuring the temperatures before and after passing through the server rack 4 using the temperature detectors 10 and 11, it is possible to confirm the temperature difference before and after passing through the server rack 4, and when the server rack 4 is operating at a low load, it is possible to confirm whether the air volume passing through the server rack 4 is appropriate.

[0034] The power measurement unit 12 is a device that measures the total power consumption of the multiple server machines 3 housed in each server rack 4, and constantly measures the power consumption when the server machines 3 are in operation, sending the measurement results to the control device 13. In a typical server room, a power distribution unit (hereinafter referred to as PDU) is installed to distribute power to the server machines, and installing a power meter in this PDU makes it possible to measure the instantaneous power supplied to each server rack 4. The power measurement unit 12 used here is capable of constant monitoring and can output a signal that can be sent to the control device 13 that controls the air conditioner 2.

[0035] The air volume detection unit provided in the air conditioner 2 can be a measuring device such as an air volume meter or a hot wire anemometer that can constantly monitor the supply air volume of the air conditioner 2, but if it is difficult to permanently install a measuring device, it may be substituted by detecting the output of the electric motor of the air conditioner 2. When estimating the air volume by detecting the output of the electric motor, it is necessary to provide the electric motor with an inverter device that can adjust the output value of the electric motor, and to obtain the relationship between the output value of the electric motor and the supply air volume during trial operation adjustment.

[0036] In the server room 1 configured as described above, by placing the server rack exhaust airflow adjustment device 20 of the present invention in the hot aisle HA, the exhaust airflow of the server rack 4 is adjusted and the exhaust wind direction is controlled.

[0037] As shown in Figures 1 and 2, the exhaust airflow adjustment device 20 is positioned facing the back of the server rack 4 at a predetermined distance d, and as shown in Figures 3 to 8, it has the appearance of a partition consisting of an airflow adjustment surface 21 fixed to a frame body 23 and legs 22 supporting the frame body 23.

[0038] The exhaust airflow adjustment device 20 is placed behind a high-load server rack (a server rack that generates more heat and operates at a higher load than the surrounding server racks, resulting in a larger exhaust airflow) and blocks or redirects the exhaust air from the high-load server rack to reduce the force of the airflow. This reduces the impact on the high-load server rack, as well as the opposite low-load server rack (a server rack that generates less heat and operates at a smaller exhaust airflow than the high-load server rack) and the surrounding low-load server racks, and also suppresses the temperature rise in the cold aisle CA, allowing the exhaust air from the high-load server rack to be discharged into the hot aisle HA. Furthermore, because the impact on the surrounding server racks 4 and the cold aisle CA is reduced, energy savings are achieved by reducing the amount of air conditioned.

[0039] Furthermore, the exhaust airflow adjustment device 20 exerts its effect simply by being placed on the back of a specific server rack 4, so it does not require a power source such as electricity, gas, or compressed air, and is portable, making it easy to move and install in any location.

[0040] The airflow adjustment surface 21 is formed in a specific shape so as to properly adjust the exhaust airflow from the server rack 4. The shape of this airflow adjustment surface 21 will be described in detail later. The airflow adjustment surface 21 is formed in a size that faces at least the entire area of ​​the server rack 4 where the server machines 3 are arranged. The airflow adjustment surface 21 may be formed from a thin plate made of a non-breathable material such as resin, metal, wood, paper, or glass, or may be formed from a perforated plate with many openings formed therein or a thin plate made of a breathable material such as a woven fabric or non-woven fabric.

[0041] The frame 23 to which the airflow adjustment surface 21 is fixed is formed into a vertically long rectangle with at least the outer periphery framed by square pipes made of metal or resin, and horizontal and vertical bars are provided within this frame as necessary. The frame 23 is formed at approximately the same height as the airflow adjustment surface 21. The plane of the space enclosed by the frame 23 is either arranged approximately perpendicular to the floor, i.e., facing the back of the server rack 4 and approximately parallel to it, or arranged with its upper end inclined in a direction away from the server rack 4.

[0042] The legs 22 supporting the frame body 23 may have any shape as long as the frame body 23 and the airflow adjustment surface 21 fixed thereto can stand on their own, and may be fixed as in the illustrated example, or may be fitted with casters with stoppers to allow easy movement. It is also preferable that the frame body 23 be switchable between a state in which it faces the back surface of the server rack 4 almost parallel to the server rack 4, and a state in which the upper end of the frame body 23 is inclined at an arbitrary angle in a direction away from the server rack 4.

[0043] Hereinafter, a detailed description will be given of the airflow adjustment surface 21. Based on the results of experiments described below, the airflow adjustment surface 21 is of any one of a curved type, a flat type, and a vertical blade type, which are found to have particularly excellent performance.

[0044] 3 and 4, the curved airflow adjustment surface 21 is configured as a curved plate with a widthwise center portion recessed in the vertical direction relative to the back surface of the server rack 4, and both widthwise ends of this curved plate (airflow adjustment surface 21) are fixed to both sides of the frame body 23, so that the curved plate is arranged so as to protrude rearward in a curved shape from both sides of the frame body 23. The curved shape (cross-sectional shape) of the airflow adjustment surface 21 is substantially the same over its entire length in the vertical direction, and both vertical ends are open and not fixed to the frame body 23. As a result, exhaust airflow from the server rack 4 flowing toward the curved airflow adjustment surface 21 collides with the airflow adjustment surface 21 and is temporarily blocked. Thereafter, the airflow flows up and down over the airflow adjustment surface 21 and also flows out in the widthwise direction, thereby reducing the force of the airflow.

[0045] 5 and 6, the flat airflow adjustment surface 21 is made up of a flat plate, which is fixed to the frame body 23 so as to close the space within the frame body 23. As a result, the exhaust airflow from the server racks 4 flowing toward the flat airflow adjustment surface 21 collides with the airflow adjustment surface 21 and is blocked, and the force of the airflow is reduced by being diffused to the surrounding area. The flat plate is not particularly limited as long as its outer periphery is fixed to the frame body 23 so as to close the space within the frame body 23. A flat plate with a flat surface over the entire surface may be used, or a corrugated plate with unevenness or a plate with reinforcing material in the middle or outer periphery may be used.

[0046] 7 and 8, the vertical blade type airflow adjustment surface 21 is configured by arranging a plurality of vertically long blade members 24 in the width direction at an angle to the back surface of the server rack 4. As a result, a long and narrow gap is formed between adjacent blade members 24, 24 in the width direction, penetrating the front and back, and air can pass through this gap to the back side.

[0047] The blade members 24 are arranged on both sides of the widthwise center of the airflow adjustment surface 21, with their inclination directions opposite to each other. That is, as shown in FIG. 8(C), the blade members arranged on both sides of the widthwise center are arranged with their side ends at the widthwise center inclined away from the server rack 4. The blade members 24, 24 arranged immediately on both sides of the widthwise center are integrated by connecting their side ends to each other, forming a V-shape in a plan view, preventing airflow from passing through the widthwise center. The exhaust airflow from the server rack 4 flowing toward the vertical-blade-shaped airflow adjustment surface 21 passes through the gaps between adjacent blade members 24, 24 to the back side of the airflow adjustment surface 21. While passing through these gaps, the airflow direction is changed toward the widthwise center. The airflows from both sides collide behind the exhaust airflow adjustment device 20, reducing the force of the airflow.

[0048] The blade members 24 may be arranged so that their outer side edges in the width direction are inclined in a direction away from the server rack 4. All the blade members 24 may also be arranged so that they are inclined in the same direction.

[0049] The blade members 24 may be arranged so as to extend integrally over the entire vertical length of the frame body 23, or may be arranged in sections separated by one or more horizontal bars 23a that divide the frame body 23 into multiple sections in the vertical direction.

[0050] The exhaust airflow adjustment device 20 having the above configuration may be configured so that the airflow adjustment surface 21 can be easily replaced with any curved, flat, or vertical blade type airflow adjustment surface 21 by making the airflow adjustment surface 21 detachable from the frame body 23, or by making the frame body 23 to which the airflow adjustment surface 21 is attached detachable from the leg portion 22. [Example]

[0051] Next, an experiment to verify the effect of the exhaust airflow control device 20 according to the present invention will be described.

[0052] The plan and elevation views of the server room 1 used in the experiment are shown in Figures 9 and 10. The air flow in the server room 1 is such that conditioned air is blown into the cold aisle CA from air intakes 8 installed on the wall of the server room 1, passes through the server racks, flows into the hot aisle HA, and then forms an air circulation system in which air returns to the air conditioners 2 through exhausts 7 installed on the ceiling of the hot aisle HA.

[0053] In the experiment, the temperature of the conditioned air supplied from the air conditioner 2 was kept constant, and the temperature at each point was measured while changing the conditioned air volume V (air flow rate) of the air conditioner 2. Note that the operating conditions of the server racks 4a to 4f were kept constant for each conditioned air volume V.

[0054] The temperature measurement points in the cold aisle CA were six points, Pa to Pf, and the vertical temperature distribution was measured at intervals of 300 mm from 400 mm above the floor at each point, as shown in Figure 10. This makes a total of 6 x 6 = 36 temperature measurement points in the cold aisle CA. The temperature measurement point in the hot aisle HA was the temperature of the exhaust airflow near server rack 4 on the rear side.

[0055] As shown in Figure 9, the operating conditions for each server rack 4a to 4f were such that only server rack 4b was operated at a high load of 30kW, while the other server racks 4a, 4c to 4f were operated at a low load of 6kW. Therefore, 4b is a high-load server rack, and 4a, 4c to 4f are low-load server racks. Note that the other server racks without symbols were not in operation, and the entire rack was closed off with a closing plate to prevent conditioned air and exhaust air from passing through.

[0056] (1) If no measures are taken First, we will explain the case where no measures are taken, i.e., where nothing is installed behind the server rack 4. With each of the server racks 4a to 4f operating under the above operating conditions, the temperature at each point was measured while changing the volume V of conditioned air from the air conditioner 2. The results are shown in Figure 11.

[0057] Here, the ventilation flow rate ratio κ on the horizontal axis is a dimensionless number calculated by the following equation (1).

number

[0058] When the ventilation flow ratio κ is constant, the total exhaust air volume of server machine 3 is ΣQ s When the volume of air conditioned air V changes, the volume of air conditioned air V also changes at a certain rate. s In the case of high load operation with a large value, the conditioned air volume V of air conditioner 2 also increases, and the total exhaust air volume of server machine 3, ΣQ s In the case of low-load operation where κ is small, the conditioned air volume V of the air conditioner 2 also becomes small, making it difficult for the conditioned air volume to become excessive. Also, even when the utilization rate of the server machine 3, which was operating at a high load, drops and the machine enters low-load operation, by determining the conditioned air volume V of the air conditioner 2 under the condition that the ventilation flow rate ratio κ is kept constant, it is possible to reduce operation due to excessive capacity.

[0059] The cold aisle temperature rise ΔT [°C] on the vertical axis is defined by the following equation (2).

number

[0060] The cold aisle maximum temperature T cmax is the maximum temperature of the cold aisle CA measured at temperature measurement points Pa to Pf when operating at a predetermined ventilation flow ratio κ. When measuring temperatures while gradually lowering the ventilation flow ratio κ, it can be assumed that the temperature will tend to rise from the vicinity of the server rack 4, so the temperature measurement points for the cold aisle CA should be installed near the server rack 4 (within 100 mm). As it is difficult to predict at what height position on the server rack 4 the temperature will tend to rise, it is advisable to install multiple points, preferably three or more points, and more preferably three to ten points, at predetermined intervals in the vertical direction.

[0061] The cold aisle supply air temperature Tc is the temperature of the conditioned air supplied to the cold aisle CA, and is preferably the temperature of the cold aisle CA at a point some distance away from the server racks 4 that is less susceptible to the influence of air leaking from the hot aisle HA into the cold aisle CA. This temperature measurement point can be a temperature detector 10 installed on the wall of the server room 1 or nearby, as shown in Figures 1 and 2, or a temperature detector installed at the air intake 8 or nearby (including inside the air intake duct). This cold aisle intake air temperature T c Since it is often necessary to monitor the temperature constantly during operation, it is desirable to use the measurement value from a permanently installed thermometer as the standard. However, the cold aisle intake air temperature T c Assuming that there is a discrepancy between the temperature of the supply air to each server rack 4 and the representative point in the cold aisle CA, c It is desirable to simultaneously measure the cold aisle supply air temperature T c The temperature controller 100 maintains the server room 1 at a specified temperature and keeps it almost constant within a range that does not cause condensation on the server machines 3, and maintains the server room 1 within a specified temperature range by adjusting the volume V of conditioned air from the air conditioner 2.

[0062] From the relationship between the ventilation flow rate ratio κ and the cold aisle temperature rise ΔT in FIG. 11, the ventilation flow rate ratio κ when the cold aisle temperature rise is ΔT can be calculated. This ventilation flow rate ratio κ at ΔT indicates the minimum conditioned air volume V that the air conditioner 2 must ensure in order to keep the allowable temperature rise in the cold aisle CA (cold aisle temperature rise ΔT) below ΔT under specified server rack thermal load conditions. This value can be read from the graph in FIG. 11 as κ at ΔT. The specific numerical range of the cold aisle temperature rise ΔT varies depending on the maximum thermal load of the server rack 4, the number of servers installed, the set temperature, the volume of the room, and other factors. However, a range that ensures reliable cooling of the server machines 3 housed in the server rack 4, reliable prevention of adverse effects due to temperature rise of the server machines 3, and stable control is preferably 3°C or less, and more preferably 1°C or less. In this embodiment, the stricter range of 1°C or less is adopted. That is, it is estimated that when the cold aisle temperature rise ΔT exceeds 1° C., air from the hot aisle HA leaks into the cold aisle CA, causing a temperature rise in the cold aisle CA.

[0063] If the ventilation flow rate ratio κ that results in a cold aisle temperature rise ΔT of 1°C is κ1, then, from Figure 11, κ1 will be 2.03 if no measures are taken. This means that when κ is smaller than κ1, ΔT will be greater than 1°C, and in order to keep the cold aisle temperature rise ΔT below 1°C, the volume of conditioned air V from air conditioner 2 must be at least 2.03 times the total exhaust volume of server machine 3.

[0064] Next, for the high-load server rack and the low-load server rack, the temperature difference ΔT between the intake air supplied from the cold aisle CA and the exhaust air discharged from the back of server rack 4 H , ΔT L The high load server rack was calculated as 4b, and the low load server rack was calculated as 4a.

[0065] Intake and exhaust temperature difference ΔT of high-load server rack 4b Hand the intake and exhaust temperature difference ΔT of low-load server rack 4a L are expressed by the following equations (3) and (4), respectively.

number

[0066]

number

[0067] This is shown in graphs in Fig. 12 and Fig. 13. When the ventilation flow ratio κ is κ1 (=2.03), the intake / exhaust temperature difference ΔT of the high-load server rack 4b is H1 is 17.2°C from Figure 12. Similarly, when the ventilation flow rate ratio κ is κ1 (=2.03), the intake / exhaust temperature difference ΔT L1 From Figure 13, this is 15.0°C.

[0068] (2) Ready-made products Next, we will explain a case where a countermeasure is taken by providing a ready-made product in which multiple airflow control plates that are inclined diagonally upward are arranged at equal intervals in the vertical direction on the back of the server rack, as disclosed in the above-mentioned Patent Document 5. These ready-made products include ready-made product 1 in which the guide member 50 shown in Fig. 14 is arranged on the inside of the back of the server rack inclined diagonally upward as shown in Fig. 15, and ready-made product 2 in which the guide member 50 is arranged so as to protrude diagonally upward from the back of the server rack as shown in Fig. 16.

[0069] First, the dimensions of the finished product 1 will be described. The guide member 50 has a width W A is 80mm, length L A The inclination angle θ of the guide member 50 is 500 mm. A was set to 60°.

[0070] After taking measures using this ready-made product 1, we conducted the same experiment as above, and when we calculated the ventilation flow rate ratio κ1 that would result in a cold aisle temperature rise ΔT = 1 [℃], we found that κ1 = 1.31.

[0071] Here, in order to evaluate the effect of reducing the ventilation flow rate ratio κ1 by the measures, a reduction coefficient α expressed by the following equation (5) is defined.

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[0072] As a result of the countermeasure using existing product 1, the reduction coefficient α was 1.31 / 2.03 = 0.65. This means that by installing existing product 1, the same air-conditioning environment can be maintained even if the air conditioner's air volume is reduced by 35%, and the load on the air conditioner is reduced by 0.65 times.

[0073] Similarly, the intake and exhaust temperature difference ΔT of the high-load server rack 4b when the ventilation flow ratio is κ1 H1 and the intake and exhaust temperature difference ΔT of the low-load server rack 4a when the ventilation flow rate ratio is κ1 L1 , respectively, ΔT H1 =21.4[℃], ΔT L1 =16.9[℃].

[0074] Here, in order to evaluate the influence of the countermeasures on the intake / exhaust temperature difference, the influence coefficient β expressed by the following equations (6) and (7) is used. H , β L Define

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[0075] The influence coefficient β H , β L is set at 1 as the boundary, and values ​​greater than 1 mean that the intake / exhaust temperature difference has increased as a result of the measures taken. This increase in intake / exhaust temperature difference means that the amount of heat generated by the server rack 4 remains constant, and therefore the air volume passing through the server rack 4 has decreased. Therefore, the impact coefficient β H , β LIf is greater than 1, it can be determined that the countermeasures taken have reduced the air volume passing through server rack 4. A reduction in the air volume required for cooling could result in a decrease in the processing power of the server machine or cause it to malfunction.

[0076] As a result of measures using ready-made product 1, the impact coefficient β of high-load server rack 4b H is 21.4 / 17.2=1.24, and the impact coefficient β of low-load server rack 4a L is 16.9 / 15.0=1.13, both of which exceed 1.

[0077] Next, the ready-made product 2 will be described. Compared with the ready-made product 1, the ready-made product 2 has a width W of the guide member 50. A It is the same as the ready-made product 1 except that ' is changed to 250 mm and the guide member 50 is positioned so that it protrudes from the back of the server rack 4.

[0078] After taking measures using this existing product 2, we conducted the same experiment as above. The results are summarized in Table 1. The same tendency as that of existing product 1 was observed with existing product 2. [Table 1]

[0079] From the above results, there are three points to keep in mind when taking measures to prevent temperature rise in cold aisle CA: (a) the effect of reducing the ventilation flow ratio κ1, (b) the impact on the high-load server rack 4b, and (c) the impact on the surrounding low-load server racks.

[0080] Regarding (a) above, the reduction effect α is an index showing the reduction effect of the air supply volume of the air conditioner 2, and the smaller the value, the greater the effect. However, if α is below 1, it is expected that the air supply volume of the air conditioner will be reduced more effectively than if no measures were taken, so the target value is set to be α less than 1.

[0081] In addition, for the above (b) and (c), the influence coefficient β H , β LAlthough it is difficult to avoid the effect on the airflow through the server rack by taking some measures on the back of the server rack, it is desirable that the effect is smaller than that of existing product 1 and existing product 2, so the smaller value of the two is adopted, and β H is less than 1.24, β L The target value is 1.13 or less.

[0082] (3) In the case of an exhaust airflow adjustment device Next, a case where a countermeasure is taken by installing an exhaust airflow adjustment device in the hot aisle HA at the rear of the high-load server rack 4b will be described.

[0083] As shown in Figure 17, experiments were conducted using an exhaust airflow control device 20 (equipped with a flat, vertical blade, or curved airflow control surface 21) according to the present invention as an example, and an exhaust airflow control device 51 equipped with a horizontal blade or V-shaped airflow control surface 52 as a comparative example.

[0084] (3-1) Planar type (Example) As an exhaust airflow control device 20 according to the present invention, an exhaust airflow control device 20 having a flat airflow control surface 21 as shown in Figure 17(A) was installed at a distance d of 600 mm from the server rack 4, and an experiment was conducted in the same manner as described above.

[0085] The results are shown in Table 2 and FIG. [Table 2]

[0086] In the flat type, κ1=1.40 and the reduction coefficient α is 0.69, which is expected to reduce the supply air volume of air conditioner 2 by 31% compared to no countermeasures. H is 1.06, β Lis 1.07, both of which are lower than existing products and within the target values, resulting in a small decrease in the air volume passing through the server rack 4. Therefore, the exhaust airflow adjustment device 20 equipped with the flat airflow adjustment surface 21 can reduce the impact of the exhaust from the high-load server rack 4b on the surrounding area, suppress the temperature rise in the cold aisle CA, and achieve energy savings by reducing the air-conditioning air volume V.

[0087] (3-2) Vertical feather type (Example) As an exhaust airflow adjustment device 20 according to the present invention, an exhaust airflow adjustment device 20 having a vertical blade-type airflow adjustment surface 21 as shown in Figures 17(B) and 19 was installed by changing the position of the separation distance d from the server rack 4, and an experiment was conducted in the same manner as described above.

[0088] The results are shown in Table 3 and FIG. [Table 3]

[0089] With the vertical blade type, differences were observed in the results, with the reduction coefficient α being 0.67 to 0.77, and a reduction in the supply air volume of air conditioner 2 of 23 to 33% can be expected compared to no countermeasures. H , β L are all less than 1, and it is expected that the amount of air passing through the server rack 4 will increase compared to when no countermeasures are taken. Therefore, the exhaust airflow adjustment device 20 equipped with the vertical blade type airflow adjustment surface 21 can reduce the impact of the exhaust from the high-load server rack 4b on the surrounding area, suppress the temperature rise in the cold aisle CA, and achieve energy savings by reducing the amount of air-conditioned air V.

[0090] (3-3) Curved type (Example) As the exhaust airflow control device 20 according to the present invention, the exhaust airflow control device 20 having the curved airflow control surface 21 shown in FIG. 17(C) and FIG. 21 is used. B and the inclination angle θ B The position was changed and the server rack 4 was installed at a distance d from the server rack 4, and the experiment was carried out in the same manner as above.

[0091] The results are shown in Table 4 and FIG. [Table 4]

[0092] For the curved type, when the separation distance d is 600 mm, the inclination angle θ B In the range of 0 to 10°, 5° is the smallest κ1, and the influence coefficient β H , β L The results were lower than those of existing products 1 and 2. When the separation distance d was reduced (520 mm), κ1 increased slightly. The inclination angle θ B If is 5°, the arc length W B At 650 mm, the reduction coefficient α is 0.65, while the arc length W B At a distance of 600 mm, the reduction coefficient α was 0.67. Therefore, the exhaust airflow adjustment device 20 equipped with the curved airflow adjustment surface 21 can reduce the impact of the exhaust from the high-load server rack 4b on the surrounding area, suppress the temperature rise in the cold aisle CA, and achieve energy savings by reducing the volume V of air-conditioned air.

[0093] Next, as a modified example of the curved surface type, the curved airflow adjusting surface 21 is changed to a perforated plate, and the hole diameter (opening ratio) and the inclination angle θ of the perforated plate are changed. B The experiment was carried out in the same manner as above, with the separation distance d as a parameter.

[0094] The results are shown in Table 5 and FIG. [Table 5]

[0095] For the porous curved type, although there are differences depending on the conditions, the reduction coefficient α was a very small value of 0.60 to 0.65. This has the effect of reducing the supply air volume by up to 40% compared to no countermeasures. Also, the reduction coefficient α tends to decrease as the opening ratio (hole diameter) increases, and as the separation distance d decreases. Impact coefficient β H , β LThe results were both lower than those of existing products 1 and 2. Therefore, exhaust airflow adjustment device 20 equipped with perforated curved airflow adjustment surface 21 can reduce the impact of exhaust from high-load server rack 4b on the surrounding area, suppress the temperature rise in the cold aisle CA, and achieve energy savings by reducing the volume V of air-conditioned air.

[0096] (3-4) Horizontal feather type (comparison example) As a comparative example, an exhaust airflow adjustment device 51 having a horizontal blade type airflow adjustment surface 52 shown in FIG. 17(D) and FIG. 25 was used. C , inclination angle θ C The separation distance d was changed and the device was installed at a predetermined position, and the experiment was carried out in the same manner as above.

[0097] The exhaust airflow adjuster 51 equipped with the horizontal blade-type airflow adjustment surface 52 is configured by arranging a plurality of the airflow adjustment surfaces 21 of the exhaust airflow adjuster 20 according to the present invention at equal intervals in the vertical direction, with the upper ends of the horizontally elongated blade members 53 inclined in a direction away from the server rack 4, as shown in Fig. 25. Therefore, a narrow gap in the width direction is formed between the vertically adjacent blade members 53, and in the process of passing through this gap, the inclination angle θ of the blade members 53 C The airflow will change direction depending on the

[0098] The experimental results for the horizontal blade type are shown in Table 6 and Figure 26. The shaded areas in the table indicate the influence coefficient β of the low-load server rack. L indicates that the value exceeds the aforementioned target value (1.13). [Table 6]

[0099] In the horizontal blade type, although there are differences depending on the conditions, the reduction coefficient α is 0.65 to 0.83, which is a reduction of 17 to 35% compared to no countermeasure. C At 400mm, the influence coefficient β L Since the target value of W exceeds the target value of W, the width W of the blade member 53 C When the influence coefficient β is large, LIn addition, when the separation distance d is 50 mm and 300 mm, the influence coefficient β L Since the target value of is exceeded, if the separation distance d is small, the influence coefficient β L Therefore, the exhaust airflow adjustment device 51 having the horizontal blade type airflow adjustment surface 52 may have a large effect on the low-load server rack 4a.

[0100] (3-5) V-shaped (comparative example) As a comparative example, an exhaust airflow control device 51 having a V-shaped airflow control surface 52 shown in FIG. 17(E) and FIG. 27 was used, and the inclination angle θ D The distance d was changed and the sensor was installed at a predetermined position, and the experiment was carried out in the same manner as above.

[0101] In the exhaust airflow control device 51 equipped with the V-shaped airflow control surface 52, the airflow control surface 21 of the exhaust airflow control device 20 according to the present invention is arranged in a V-shape in plan view, as shown in Fig. 27, with two blade members 53 extending over the entire vertical length butting against each other at the center in the width direction so as to protrude away from the server rack 4. The cross-sectional shape of this airflow control surface 52 is substantially the same over the entire vertical length, and both vertical ends are open. As a result, exhaust airflow from the server rack 4 flowing toward the airflow control surface 52 collides with the airflow control surface 52 and is temporarily blocked. Thereafter, the airflow control surface 52 flows vertically and also flows out in the width direction, thereby reducing the force of the airflow.

[0102] The V-shaped experimental results are shown in Table 7 and Figure 28. The bold lines in the table indicate the influence coefficient β of the low-load server rack. L indicates that the value exceeds the aforementioned target value (1.13). [Table 7]

[0103] For the V-shaped design, the reduction coefficient α is 0.67 to 0.68, and the impact coefficient β for high-load server racks His 1.17 to 1.29, the target value (α is 1, β H was below 1.24), but the impact coefficient β of the low-load server rack L The results were 1.17 to 1.29, which exceeded the target value (1.13). Therefore, the exhaust airflow adjustment device 51 equipped with the V-shaped airflow adjustment surface 52 has a large effect on the low-load server rack 4a.

[0104] (summary) The ventilation flow rate ratio κ1 and the intake / exhaust temperature difference ΔT from the above results H1 , ΔT L1 , reduction coefficient α, influence coefficient β H , β L The influence coefficient β is listed in ascending order of the ventilation flow rate ratio κ1 in Table 8. H , β L Regarding each target value (β H is 1.24, β L The values ​​exceeding 1.13) are enclosed in a thick line. [Table 8]

[0105] (1) The planar type has a simple structure with α=0.69 and β H and β L is smaller than 1.1, resulting in high performance.

[0106] (2) The vertical blade type has a blade member 24 with a width of 85 mm and an inclination angle of 30°, and is installed at a distance d of 300 to 600 mm, thereby achieving β H , β L are all smaller than 1.0, and α is between 0.67 and 0.77.

[0107] (3) The curved type has a suitable separation distance d of about 600 mm and an arc length W B By setting the value to 600-650mm, α becomes 0.65-0.68, and β H , β L is also within the target value.

[0108] In addition, when a perforated plate is used as the curved plate constituting the airflow adjusting surface 21, α=0.60 to 0.65, β H =1.07~1.10, β L =0.95~1.09, and all values ​​are smaller than those of existing products.

[0109] [Other examples] (1) The present invention is not limited to application to a server room 1 in which a cold aisle CA and a hot aisle HA are formed, but can also be applied to suppressing the impact of exhaust from a specific high-load rack on other server racks in a server room in which server racks are arranged. [Explanation of symbols]

[0110] 1...server room, 2...air conditioner, 3...server machine, 4...server rack, 5...row of server racks, 6...partition board, 7...exhaust port, 8...air intake port, 10, 11...temperature detector, 12...power measuring unit, 13...control device, 20 exhaust airflow adjustment device, 21...airflow adjustment surface, 22...legs, 23...frame, 24...blade member

Claims

1. An exhaust airflow adjustment device for adjusting the exhaust airflow of a server rack in a server room provided with a row of server racks, each row of server racks accommodating server machines in multiple tiers in the vertical direction, arranged with the front and back facing in the same direction, The exhaust airflow adjustment device has an airflow adjustment surface that is disposed facing the rear surface of the server rack at a predetermined distance, The airflow adjustment surface is formed in either a curved shape consisting of a curved plate with a recess in the center of the width direction along the vertical direction on the back of the server rack, or a perforated curved shape in which a number of openings are formed in the curved plate.

2. 2. The exhaust airflow adjustment device for a server rack according to claim 1, wherein the upper end of the curved or perforated curved airflow adjustment surface is inclined in a direction away from the server rack.

3. 2. The exhaust airflow adjustment device for a server rack according to claim 1, wherein the exhaust airflow adjustment device is disposed at a distance of 300 to 600 mm from the rear surface of the server rack.

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