Data center server racks contain a large amount of electronics, which generate large quantities of heat. Consequently, a large amount of power is needed to cool the electronics. A contributing factor to the large power consumption is how cooling fluid or air is provided to the server racks.
In one aspect, this disclosure features a cooling system. The cooling system includes a ceiling plenum formed between a first ceiling and a second ceiling of a building, and a containment assembly disposed above at least one hot aisle formed by rows of server racks and extending through an aperture in the first ceiling. The containment assembly directs fluid from the hot aisle into the ceiling plenum. The cooling system includes a fluid velocity sensor that measures velocity of fluid flowing in the hot aisle or the containment assembly and a temperature sensor that measures the temperature of the fluid flowing in the hot aisle or the containment assembly. The cooling system includes at least one fan and heat exchanger assembly and a controller that adjusts a speed of at least one fan of the at least one fan and heat exchanger assembly based on the measured temperature and velocity. The at least one fan of the at least one fan and heat exchanger assembly causes fluid to flow from the ceiling plenum, through at least one heat exchanger of the at least one fan and heat exchanger assembly, and to the plurality of server racks.
In aspects, the at least one fan and heat exchanger assembly includes a first row of fan and heat exchanger assemblies and a second row of fan and heat exchanger assemblies adjacent to the first row of the fan and heat exchanger assemblies.
In aspects, the velocity sensor and the temperature sensor is implemented by an anemometer.
In aspects, the cooling system includes a redundant anemometer.
In aspects, the at least one fan and heat exchanger assembly is disposed inside an outdoor enclosure outside of the building and adjacent to a wall of the building, and the at least one fan causes fluid to flow through an aperture in the wall to the server racks.
In aspects, the cooling system includes a floor plenum formed between a floor and a slab of the building, and an air duct fluidly coupled between the ceiling plenum and the floor plenum. The at least one fan and heat exchanger assembly is disposed within the air duct and causes air to flow through the air duct to the floor plenum and through apertures in the floor to the server racks.
In aspects, the cooling system includes an interior wall disposed within the building between the server racks and the at least one fan and heat exchanger assembly and extending from a floor of the building so as to connect with the first ceiling and form an interior wall aperture between the second ceiling and a top portion of the interior wall.
In aspects, the heat exchangers are disposed between the interior wall and the fans, and the fans are configured to cause air to flow from the server racks, through the interior wall aperture, to the ceiling plenum, and through the containment assembly.
In aspects, fans are disposed between the interior wall and heat exchangers, and the fans cause air to flow from the ceiling plenum, through the interior wall aperture, and to the server racks via the fan and heat exchanger assemblies.
In aspects, the at least one fan and heat exchanger assembly includes a fan and heat exchanger assembly enclosure.
In yet another aspect, this disclosure features another cooling system. The cooling system includes a first containment assembly disposed within a building and disposed adjacent to at least one hot aisle formed by rows of server racks, a fluid velocity sensor that measures velocity of fluid flowing in the first containment assembly, a temperature sensor that measures the temperature of the fluid flowing in the first containment assembly, a first row of fan and heat exchanger assemblies disposed outside of the building, a second row of fan and heat exchanger assemblies disposed outside of the building and disposed adjacent to the first row of fan and heat exchanger assemblies, and a controller that adjusts a speed of fans of the first and second rows of the fan and heat exchanger assemblies based on the measured temperature and velocity. Fans of the fan and heat exchanger assemblies cause air to flow from the hot aisle, through the first containment assembly, through heat exchangers of the fan and heat exchanger assemblies, and to the server racks.
In aspects, the first containment assembly is disposed between a side of the hot aisle and at least one aperture in an exterior wall of the building, and the first and second rows of the fan and heat exchanger assemblies are in fluid communication with the first containment assembly via the at least one aperture in the exterior wall.
In aspects, the first containment assembly is disposed above the hot aisle.
In aspects, the cooling system includes a second containment assembly disposed above the first containment assembly.
In aspects, the cooling system includes a fan and heat exchanger enclosure housing the fan and heat exchanger assemblies.
In yet another aspect, this disclosure features yet another cooling system. The cooling system includes a first containment assembly disposed within a building and disposed adjacent to at least one hot aisle formed by rows of server racks, a fluid velocity sensor that measures velocity of fluid flowing in the containment assembly, a temperature sensor that measures the temperature of the fluid flowing in the containment assembly, first and second rows of fan and heat exchanger assemblies disposed within the building at a height above the height of the server racks; and a controller that adjusts a speed of fans of the first and second rows of the fan and heat exchanger assemblies based on the measured temperature and velocity. Fans of the fan and heat exchanger assemblies cause air to flow from the hot aisle, through the first containment assembly, through heat exchangers of the fan and heat exchanger assemblies, and to the server racks.
In aspects, the first containment assembly is disposed to a side of the hot aisle, and the fan and heat exchanger assemblies are disposed above and in fluid communication with the first containment assembly.
In aspects, the cooling system includes a second containment assembly disposed above the first containment assembly, and the fan and heat exchanger assemblies are coupled to and in fluid communication with the second containment assembly.
In yet another aspect, this disclosure features a method of cooling server racks. The method includes sensing a fluid temperature in or near at least one hot aisle defined between rows of server racks; if the fluid temperature is greater than a predetermined fluid temperature, increasing, by a predetermined speed, a speed of at least one fan circulating fluid through the server rack, the hot aisle, and a heat exchanger; if the fluid temperature is less than the predetermined fluid temperature, measuring fluid velocity and determining whether the fluid velocity is greater than a predetermined velocity; and if the measured fluid velocity is greater than the predetermined velocity, decreasing the speed of the fans by another predetermined speed.
In aspects, the fluid temperature and the fluid velocity are measured within a containment assembly disposed adjacent to the hot aisle.
In aspects, the fluid temperature and the fluid velocity are measured by an anemometer.
One or more aspects of this disclosure are particularly pointed out and distinctly claimed as examples in the claims at the conclusion of the specification. The foregoing and other objects, features, and advantages of this disclosure may be more readily understood by one skilled in the art with reference being had to the following detailed description of several embodiments thereof, taken in conjunction with the accompanying drawings wherein like elements are designated by identical reference numerals throughout the several views, and in which:
The figures depict embodiments of this disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of this disclosure described herein.
The modular air cooling and distribution systems of this disclosure allow for great flexibility, scalability, ease of installation, and reduced energy consumption for cooling of large, open, indoor areas such as data centers. Combinations of a basic fan/heat exchanger modular assembly may be configured in many ways to best accommodate a given building's overall design.
Embodiments of this disclosure relate to an easy-to-install, low-cost, low-air-pressure-drop, and modular air cooling and distribution system to direct the hot air from the server racks to the heat exchangers. The hot air is then cooled by a liquid, e.g., a refrigerant or chilled water, and cool air is discharged back to open space of the data center. In embodiments, high temperature air from the servers is separated from cooling air all the way to the inlet of heat exchangers by using ceiling or hot aisle containment and short ducts (when needed). By keeping hot air isolated, heat rejection can be done at higher temperatures, thus leading to more “free” cooling, lower liquid flow rate, and higher energy efficiency. The heat exchangers, as disclosed in Provisional Patent Application No. 62/380,039, the entire contents of which are incorporated by reference herein, are multi-row-flat-aluminum-tube heat exchangers with low air pressure drop. This factor, combined with the low air pressure drop through the containment/ceiling/plenum, results in low overall pressure drop and fan power. Analysis shows that some embodiments have uniform air temperature distribution across the data center.
While this disclosure uses the term “air”, other fluids in the gaseous state may be used in place of air according to embodiments of this disclosure.
Redundant anemometers 150 are coupled to the containment assembly 108 so as to measure the temperature and/or velocity of the air flowing through the containment assembly 108. In other embodiments, another type of fluid velocity sensor and fluid temperature sensor may be used in place of the redundant anemometers 150. For example, the fluid temperature sensor may be replaced by a paddle attached to a mechanical switch so that the fluid flow in the containment assembly 108 causes the paddle to move the mechanical switch back and forth and thus sense the direction of fluid flow. The fluid flow direction may alternatively be measured by any other fluid flow direction sensor known in the art. The fluid velocity sensor may be any suitable low velocity-type sensor.
The temperature and/or velocity measurements are used to control the speed of one or more of the fans of the fan and heat exchanger assemblies. For example, the fluid velocity and temperature measurements, which indicate the leakage rate of fluid between the hot aisle to the cold aisle, may be used to modulate the speed of the fans of the fan and heat exchanger assembly to neutralize the pressure inside the containment assembly. In embodiments, the anemometers 150 may be hot wire anemometers capable of sensing both air temperature and velocity simultaneously.
In embodiments, the control system may use a temperature set point and a velocity set point. For example, the temperature set point may be calculated according to the following equation:
Temp. set point=hot aisle temp.−((hot aisle temp.−cold aisle set temp)/3).
The temperature set point is used to command the fans of the fan and heat exchanger assemblies to accelerate or decelerate. The velocity set point may be used to fine tune the fan speed to minimize the air leakage. For example, the velocity set point may be used to decelerate the fan speed.
The control system may operate in a manual mode and an automatic mode. In the manual mode, the fans are set at a fixed speed, which overrides the automatic settings. For example, the initial velocity set point may be set to a predetermined velocity, e.g., 150 ft/min. In the automatic mode, when a low load is applied, the control system may first determine whether the hot aisle and cold aisle set temperature is less than, for example, a predetermined temperature, e.g., 5° F. If the hot aisle and cold aisle set temperature is less than 5° F., the fan speed is maintained at a minimum speed, which may be a predetermined minimum speed. If the calculated total IT load divided by the total number of active fan and heat exchanger assemblies is less than a predetermined percentage (e.g., 30%) or if the temperature differential between the inlet and discharge temperature of the fan and heat exchanger assemblies is less than a predetermined temperature (e.g., 10° F.), the fan speed may be calculated according to the following example equation:
% of Full Fan Speed=IT Load×130/Fan & Heat Exchanger Assembly Max Air Volume×100
If the calculated total IT load divided by the total number of active fan and heat exchanger assemblies is more than a predetermined percentage (e.g., 30%) and the temperature differential between the inlet and discharge temperature of the fan and heat exchanger assemblies is more than a predetermined temperature (e.g., 10° F.), the percentage of full fan speed may be determined as follows. If the reading from the anemometer is higher than a temperature set point (e.g., 10° F.), the fan speed is increased by a predetermined number of rotations per minute (RPM) (e.g., 100 RPM). The fan speed continues to increase until the sensed temperature is less than the temperature set point. If the temperature reading from the anemometer is lower than the temperature set point and the velocity reading from the anemometer is higher than the velocity set point (e.g., 150 ft/min), the fan speed is decreased (e.g., the fan speed is decreased by 100 RPM or a PID controller for controlling the velocity is applied based on the anemometer's readings).
If the temperature reading from anemometer is lower than the temperature set point and the velocity reading from the anemometer is lower than the velocity set point, which may depend on, for example, the site conditions (e.g., 75 ft/min or 150 ft/min), the fan speed is not changed. In some embodiments, if the anemometer measurement is unstable for either temperature or velocity, the controller may apply the average measurement over time (e.g., over 3-5 seconds) instead of the instantaneous measurement.
Mechanical and electrical chases 204 are disposed between the guard or louvre sections 202 and may be disposed between the fans and/or heat exchangers of the fan and heat exchanger assemblies. Wall openings or apertures 206 are formed to receive the return air conduits 208 and the guard or louvre sections 202. In embodiments, the return air conduits 208 may be combined into a single or common return air conduit that feeds into the plenum room 106. The modular air wall section also includes removable return air panels 208 which may be removed to receive additional fluid ducts to carry more return air from the ceiling plenum 112 into the plenum room 106 as further cooling capacity is needed.
The speed of the fans may be controlled to match server air flow by using a hot-wire anemometer to ensure a certain air flow rate out of the hot aisle containment area or assembly.
If the temperature is not greater than the predetermined temperature, it is determined, in block 1608, whether the anemometer velocity is greater than a predetermined velocity, e.g., 150 ft/min. If the anemometer velocity is greater than the predetermined velocity, the fan speed is decreased by the predetermined speed or another predetermined speed, in block 1610. If the anemometer velocity is not greater than the predetermined velocity, the process returns to block 1602 to read the temperature from the anemometer.
As illustrated in
Liquid (e.g., glycol and water) flow in the heat exchangers may be modulated to maintain the desired air discharge temperature. Aside from mechanical redundancy when more than one module is used, the entire system employs network redundancy for control by way of any suitable communications network.
Any suitable heat exchanger design may be used in embodiments of this disclosure including embodiments of the heat exchanger disclosed in International Application No. PCT/US2017/048969 titled “Cooling Systems and Methods Using Single-Phase Fluid and a Flat Tube Heat Exchanger with Counter-Flow Circuiting, filed on Aug. 28, 2017,” the entire contents of which is incorporated by reference in its entirety.
Any suitable fluid cooler/chiller that provides any suitable fluid, such as a liquid, to heat exchangers may be used in the heat exchangers of the fan and heat exchanger assemblies according to embodiments of this disclosure including embodiments of the fluid cooler/chiller disclosed in U.S. patent application Ser. No. 15/697,445 titled “Cooling Systems and Methods Using Single-Phase Fluid,” the entire contents of which is incorporated by reference herein. However, any suitable liquid, such as water or a water/glycol mixture, may be used.
Although embodiments of this disclosure have been described with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of this disclosure as defined by the appended claims.
Number | Date | Country | |
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62532680 | Jul 2017 | US |
Number | Date | Country | |
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Parent | PCT/US2018/042353 | Jul 2018 | US |
Child | 16741493 | US |