MANAGING AIRFLOW PROVISIONING
Data centers typically include multiple cooling units, such as, computer room air conditioning (CRAG) units, arranged to supply cooling airflow to a plurality of servers arranged in a rows of racks. The cooling airflow is often supplied through vent tiles distributed at multiple locations on a raised floor. More particularly, the fluid moving devices supply cooling airflow into a plenum formed beneath the raised floor and the cooling airflow is supplied to the servers through the vent tiles. The cooling units are typically operated to substantially ensure that the temperatures in the servers are maintained within predetermined temperature ranges. That is, to largely prevent the servers from reaching temperature levels at which the servers operate inefficiently or are harmful to the servers, the cooling units are typically operated to supply cooling resources at lower temperatures and/or at higher volume flow rates than are necessary to maintain the servers within the predetermined temperature ranges. This over-provisioning of cooling resources is inefficient, increases operational costs of the data center, and shortens the life span of the cooling units. Features of the present disclosure are illustrated by way of example and not limited in the following figure(s), in which like numerals indicate like elements, in which: For simplicity and illustrative purposes, the present disclosure is described by referring mainly to an example thereof. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. It will be readily apparent however, that the present disclosure may be practiced without limitation to these specific details. In other instances, some methods and structures have not been described in detail so as not to unnecessarily obscure the present disclosure. As used herein, the term “includes” means includes but not limited to, the term “including” means including but not limited to. The term “based on” means based at least in part on. In addition, the variables “l”, “m”, and “n” are intended to denote integers equal to or greater than one and may denote different values with respect to each other. Disclosed herein are a method and apparatus for managing airflow provisioning in an area, such as, a data center. More particularly, the airflow provisioning is managed through implementation of a model that describes airflow transport and distribution within the area. According to an example, the model comprises a physics based state-space model. In addition, parameters for the model are determined and the model is implemented in managing the airflow provisioning. The airflow provisioning includes the determination of the temperatures and volume flow rates of airflow supplied by a plurality of fluid moving devices as well as the volume flow rates of airflow supplied through a plurality of adjustable vent tiles. The model disclosed herein is a holistic model, in that, zonal and local level actuations are coordinated. More particularly, the model disclosed herein captures the airflow resources provisioning, transport, and distribution, and incorporates both zonal airflow actuation, including the fluid moving device supply air temperature and blower speed, and local airflow provisioning actuation (for instance, from adaptive vent tiles). One result of this coordination is that fighting among various airflow actuations is substantially eliminated, while substantially optimal airflow provisioning efficiency is attained. In another regard, implementation of the model disclosed herein enables data centers to be partitioned into fluid moving device zones of influence with adjustable levels of overlapping among the fluid moving device zones of influence. Implementation of the model disclosed herein also enables dynamic prediction of transient trajectories of the rack inlet temperatures based upon their current thermal statuses for any given zonal and local airflow actuations. In other words, the model disclosed herein may be implemented to dynamically predict how the rack inlet temperatures evolve over time. Implementation of the model disclosed herein further enables the determination of future rack inlet temperatures to be determined once current rack inlet temperatures and airflow actuations to be applied are given. In other words, future rack inlet temperatures may be determined without performing iterative equation solving. Moreover, the model disclosed herein enables all of the above features to be attained in a computationally efficient manner because, according to an example, the model is explicit and only involves relatively simple calculations. In a further regard, implementation of the model disclosed herein enables real-time airflow actuation optimization at both the zonal and local levels, for instance, through minimization of a cost function. As such, the airflow optimization techniques disclosed herein are able to detect thermal anomalies or inefficient airflow statuses and are able to correct those issues in a timely manner. Moreover, through use of a properly defined cost function(s), the apparatus disclosed herein actively seeks the optimal settings for all the fluid moving devices and local airflow provisioning actuation mechanisms to satisfy the target thermal status, while minimizing the cost function(s) of interest. With reference first to The adjustable vent tiles (AVTs) 118 In any regard, the airflow contained in the space 112 may include airflow supplied by more than one of the fluid moving devices 114 The sensors 120 As discussed in greater detail herein below, environmental condition information collected by the sensors 120 In one example, values obtained through implementation of the model are used to partition the data center 100 into a plurality of fluid moving device 114 It should be understood that the data center 100 may include additional elements and that some of the elements described herein may be removed and/or modified without departing from a scope of the data center 100. In addition, the data center 100 may comprise a data center that is in a fixed location, such as a building, and/or a data center that is in a movable structure, such as a shipping container or other relatively large movable structure. Moreover, although particular reference has been made in the description of the area 100 as comprising a data center, it should be understood that the area 100 may comprise other types of structures, such as, a conventional room in building, an entire building, etc. Although the controller 130 is illustrated in Turning now to As shown, the system 200 includes the fluid moving devices 114 In any regard, the processor 230 receives detected condition information from the sensors 120 According to an example, the controller 130 outputs the determined operational settings of the fluid moving devices 114 Various manners in which the modules 202-212 of the controller 130 may operate are discussed with respect to the methods 300-500 depicted in With reference first to According to an example, the model is a state-space model based on energy and mass balance principles. In a non-limiting example, the model is a physics based state-space model. An example of the physics based state-space model is described by the following equation: in which T represents a rack inlet temperature, k and k+1 represent discrete time steps, SATiand VFDiare a supply air temperature and a blower speed of the ith fluid moving device 114 At block 304, values for the parameters in the model are determined, for instance, by the parameter determining module 208. Generally speaking, the parameter determining module 208 determines the values for the parameters through an analysis of detected condition data received from the sensors 120 At block 306, the model is implemented in managing airflow provisioning in the data center 100, for instance, by the managing module 210. Various examples of manners in which the model is implemented at block 306 are described in greater detail with respect to With reference first to At block 404, for each of the rack inlet temperatures, ratios between each of the determined influence levels corresponding to a particular fluid moving device 114 At block 406, the data center 100 is partitioned into a plurality of fluid moving device zones of influence, for instance, by the managing module 210. The partitioning of the data center 100 includes identifying which of the rack inlet temperatures belong to which of the fluid moving device 114 Through use of the ratios between the influence levels and the respective largest influence level for each of the rack inlet temperatures instead of an absolute influence threshold to determine the fluid moving device zones of influence, the possibility of orphaned rack inlet temperatures during the partitioning process (that is, those rack inlet temperatures that do not belong to any fluid moving device zone of influence), may substantially be reduced. In addition, by tuning the overlapping threshold from 1 to 0, the partitioned zones may have the desired level of overlapping, ranging from disjoint zones to 100% overlapping between any two zones. In comparison, prior techniques for partitioning data centers do not have this flexibility because the overlapping is dependent on the absolute influence threshold, which has a relatively narrow range. Moreover, disjoint zone partitioning of a data center, for example, is impossible with the prior techniques. This is because the absolute influence threshold has to be sufficiently low to avoid orphaned rack inlet temperatures, and this low threshold will inevitably result in considerable overlapping between neighboring zones. Furthermore, the zone partition approach disclosed herein may be used for input-output pairing, which may be crucial for the development of distributed data center cooling control systems. For centralized data center cooling control design, the partition approach disclosed herein may be used to trim weak connections between the system inputs and outputs, which leads to more efficient controller design. Moreover, the tuning feature disclosed herein may also be used to adjust the level of redundancy in a data center based on operational policies (e.g., by designating varying levels of redundancy according to service level agreements, etc.). In one regard, the fluid moving device zones of influence may be implemented in determining which of the fluid moving devices 114 Turning now to At block 504, zonal and local airflow provisioning actuation are coordinated through use of the model to minimize the cost function, for instance, by the managing module 210. More particularly, for instance, a model predictive controller (MPC), shown in Additionally at block 504, the model is implemented to minimize the cost function while substantially maintaining temperature levels at the rack inlets within predetermined ranges. Through implementation of the model, which considers both the zonal and local airflow provisioning actuations for purposes of minimizing the cost function, fighting among the various zonal and local airflow provisioning actuations is substantially eliminated. The following equation describes an example in which the cost function is the total cooling power: in which the cooling power incurred by all of the fluid moving devices 114 At block 506, the coordinated zonal and local airflow provisioning actuation that minimizes the cost function accessed at block 502 is outputted, for instance, by the input/output module 202. According to an example, the settings for the VFDs and supply air temperatures in the fluid moving devices 114 An example of a control diagram 600 that includes the MPC 602 that implements the model disclosed herein is depicted in Some or all of the operations set forth in the methods 300-500 may be contained as utilities, programs, or subprograms, in any desired computer accessible medium. In addition, the methods 300-500 may be embodied by computer programs, which can exist in a variety of forms both active and inactive. For example, they may exist as software program(s) comprised of program instructions in source code, object code, executable code or other formats. Any of the above may be embodied on a computer readable storage medium. Example computer readable storage media include conventional computer system RAM, ROM, EPROM, EEPROM, and magnetic or optical disks or tapes. Concrete examples of the foregoing include distribution of the programs on a CD ROM or via Internet download. It is therefore to be understood that any electronic device capable of executing the above-described functions may perform those functions enumerated above. Turning now to The computer readable medium 710 may be any suitable non-transitory medium that participates in providing instructions to the processor 702 for execution. For example, the computer readable medium 710 may be non-volatile media, such as an optical or a magnetic disk; volatile media, such as memory; and transmission media, such as coaxial cables, copper wire, and fiber optics. The computer-readable medium 710 may also store an operating system 714, such as Mac OS, MS Windows, Unix, or Linux; network applications 716; and an airflow provisioning management application 718. The operating system 714 may be multi-user, multiprocessing, multitasking, multithreading, real-time and the like. The operating system 714 may also perform basic tasks such as recognizing input from input devices, such as a keyboard or a keypad; sending output to the display 704; keeping track of files and directories on the computer readable medium 710; controlling peripheral devices, such as disk drives, printers, image capture device; and managing traffic on the bus 712. The network applications 716 include various components for establishing and maintaining network connections, such as machine readable instructions for implementing communication protocols including TCP/IP, HTTP, Ethernet, USB, and FireWire. The airflow provisioning management application 718 provides various components for managing airflow provisioning in a data center 100, as described above. The management application 718 may thus comprise controller 130. The management application 718 also includes modules for accessing a model that describes airflow transport and distribution within the area, the model comprising a plurality of parameters, determining values for the plurality of parameters, and implementing the model in managing airflow provisioning in the data center. In certain examples, some or all of the processes performed by the application 718 may be integrated into the operating system 714. In certain examples, the processes may be at least partially implemented in digital electronic circuitry, or in computer hardware, machine readable instructions (including firmware and/or software), or in any combination thereof. Although described specifically throughout the entirety of the instant disclosure, representative examples of the present disclosure have utility over a wide range of applications, and the above discussion is not intended and should not be construed to be limiting, but is offered as an illustrative discussion of aspects of the disclosure. What has been described and illustrated herein is an example of the disclosure along with some of its variations. The terms, descriptions and figures used herein are set forth by way of illustration only and are not meant as limitations. Many variations are possible within the spirit and scope of the disclosure, which is intended to be defined by the following claims—and their equivalents—in which all terms are meant in their broadest reasonable sense unless otherwise indicated. In an implementation, a method for managing airflow provisioning in an area comprising a plurality of racks, wherein a plurality of fluid moving devices are to supply airflow to the plurality of racks through a plurality of adjustable vent tiles, includes accessing a model that describes airflow transport and distribution within the area, said model comprising a plurality of parameters, determining values for the plurality of parameters, and implementing the model to partition the area into a plurality of fluid moving device zones of influence with a desired level of overlapping among the plurality of fluid moving device zones of influence. 1. A method for managing airflow provisioning in an area comprising a plurality of racks, wherein a plurality of fluid moving devices are to supply airflow to the plurality of racks through a plurality of adjustable vent tiles, said method comprising:
accessing a model that describes airflow transport and distribution within the area, said model comprising a plurality of parameters; determining, by a processor, values for the plurality of parameters; and implementing the model to partition the area into a plurality of fluid moving device zones of influence with a desired level of overlapping among the plurality of fluid moving device zones of influence. 2. The method according to 3. The method according to 4. The method according to wherein T represents a rack inlet temperature, k and k+1 represent discrete time steps, SATiand VFDiare a supply air temperature and a blower speed of the ith fluid moving device, Ujis the opening of the jth adjustable vent tile, NCRACand Ntileare the number of fluid moving devices and adjustable vent tiles, respectively, and wherein giand bjare the parameters that capture influences of each fluid moving device i and adjustable vent tile j, respectively, and C denotes a temperature change. 5. The method according to determining influence levels of the plurality of fluid moving devices on a plurality of rack inlet temperatures; for each of the plurality of rack inlet temperatures, calculating ratios between each of the determined influence levels and a largest influence level of the determined influence levels for that rack inlet temperature; and partitioning the data center into the plurality of fluid moving device zones of influence based upon the calculated ratios. 6. The method according to setting an overlapping threshold value for the ratios, wherein overlapping threshold value is to substantially control the level of overlapping among the plurality of fluid moving device zones of influence. 7. The method according to 8. The method according to accessing a cost function; and determining a coordinated actuation of the plurality of fluid moving devices and adjustable vent tiles through use of the model to minimize the cost function while substantially maintaining rack inlet temperatures within predetermined ranges. 9. An apparatus for managing airflow provisioning in an area comprising a plurality of fluid moving devices and a plurality of adjustable vent tiles, said apparatus comprising:
a memory storing at least one module comprising machine readable instructions to:
access a model that describes airflow transport and distribution within the area, said model comprising a plurality of parameters; determine values for the plurality of parameters; and implement the model to partition the area in to a plurality of fluid moving device zones of influence with a level of overlapping among the plurality of fluid moving device zones of influence; and a processor to implement the at least one module. 10. The apparatus according to determine influence levels of the plurality of fluid moving devices on a plurality of rack inlet temperatures; for each of the rack inlet temperatures, calculate ratios between each of the determined influence levels and a largest influence level of the determined influence levels for that rack inlet temperature; and partition the data center into the plurality of fluid moving device zones of influence based upon the calculated ratios. 11. The apparatus according to access a cost function; determine a coordinated actuation of the plurality of fluid moving devices and adjustable vent tiles through use of the model to minimize the cost function while substantially maintaining rack inlet temperatures within predetermined ranges; and output the determined coordinated actuation. 12. The apparatus according to claim 19, wherein the model is described by the following equation: wherein T represents a rack inlet temperature, k and k+1 represent discrete time steps, SATiand VFDiare a supply air temperature and a blower speed of the ith fluid moving device, Ujis the opening of the jth adjustable vent tile, NCRACand Ntileare the number of fluid moving devices and adjustable vent tiles, respectively, and wherein giand bjare the parameters that capture influences of each fluid moving device i and adjustable vent tile j, respectively, and C denotes a temperature change. 13. A non-transitory computer readable storage medium on which is embedded at least one computer program, said at least one computer program implementing a method for managing airflow provisioning in an area comprising a plurality of fluid moving devices and a plurality of adjustable vent tiles, said at least one computer program comprising computer readable code to:
access a model that describes airflow transport and distribution within the area, said model comprising a plurality of parameters; determine values for the plurality of parameters; and implement the model to simultaneously control the plurality of fluid moving devices and the plurality of adjustable vent tiles, said at least one computer program further comprising computer readable code to:
access to a cost function; and determine a coordinated actuation of the plurality of fluid moving devices and adjustable vent tiles through use of the model to minimize the cost function while substantially maintaining rack inlet temperatures within predetermined ranges. 14. The non-transitory computer readable storage medium according to wherein T represents a rack inlet temperature, k and k+1 represent discrete time steps, SATiand VFDiare a supply air temperature and a blower speed of the ith fluid moving device, Ujis the opening of the jth adjustable vent tile, NCRACand Ntileare the number of fluid moving devices and adjustable vent tiles, respectively, and wherein giand bjare the parameters that capture influences of each fluid moving device i and adjustable vent tile j, respectively, and C denotes a temperature change. 15. The non-transitory computer readable storage medium according to determine influence levels of the plurality of fluid moving devices on a plurality of rack inlet temperatures; for each of the plurality of rack inlet temperatures, calculate ratios between each of the determined influence levels and a largest influence level of the determined influence levels for that rack inlet temperature; and partition the data center into the plurality of fluid moving device zones of influence with a desired level of overlapping among the plurality of fluid moving device zones of influence based upon the calculated ratios. BACKGROUND
BRIEF DESCRIPTION OF DRAWINGS
DETAILED DESCRIPTION
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