Patent Description:
The present disclosure relates in general to cooling information handling resources of a modular data center, and more particularly to using air handling units (AHUs) to selectively using uncontaminated outside air to provide directed and controlled cooling to a large scale information handling system (IHS).

As the value and use of information continue to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems (IHSes). An IHS generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes, thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, IHSes may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in IHSes allow for IHSes to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, IHSes may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.

As the capabilities of information handling systems have improved, the power requirements of IHSes and their component information handling resources have increased. Accordingly, the amount of heat produced by such information handling resources has increased. Because the electrical properties of information handling resources may be adversely affected by the presence of heat (e.g., heat may damage sensitive information handling resources and/or some information handling resources may not operate correctly outside of a particular range of temperatures), information handling systems often include cooling systems configured to cool such information handling resources.

The construction and configuration of cooling systems may be of particular difficulty in data centers. A data center will typically include multiple IHSes (e.g., servers), which may be arranged in racks. Modular data centers further arrange these racks in modular building blocks. Each IHS and its component information handling resources may generate heat, which can adversely affect the various IHSes and their component information handling resources if the generated heat is not efficiently removed or reduced. To cool information handling systems in data centers, information handling systems are often cooled via the impingement of air driven by one or more air movers. To effectively control the temperature of information handling resources, especially in installations in which a modular data center is outdoor-exposed (e.g., those placed on building roofs or elsewhere), the modular data center must provide support for extreme temperatures, weather, and airflow ranges. However, relying solely upon mechanical cooling can be costly and lead to other secondary problems with air quality and others that can negatively affect the IHSes.

Increasing use of outside air for economical cooling can subject the IHS to damage from contaminants. Gaseous, liquid and solid particulate types of contaminants can be present in outside air. One example of contaminants are corrosive substances such as chlorine. The levels of contaminants can vary based upon weather conditions and varying human activity.

<CIT> discloses determining indoor air contaminant levels independent of outdoor contaminant levels. In one embodiment, an infinite geometric series is used to compute a true indoor air contaminant level in a room.

<CIT> relates to a dilution ventilation control system for use in a one-pass, critical environments comprising one or more one-pass, critical environments comprising, a variable source of supply airflow volume, an exhaust for completely exhausting the airflow volume supply from the critical environment and from a building comprising the critical environment through one or more exhaust ducts; and at least one an airflow control device.

In accordance with the teachings of the present disclosure, the amount of resources necessary for cooling a data center comprising information handling systems has been substantially reduced by utilization of outside air cooling when a level of contaminants in the outside air are acceptable. The amount of damage to information technology (IT) components caused by the presence of contaminants in outside air is substaintially reduced and/or eliminated via implementation of controlled intake of outside air, based on detected contaminant levels and filtering capabilities of the cooling system. Filtering of contaminants is also provided to enable an expanded use of outside air. With the information handling system being exposed to only low levels of contaminates in the cooling air, the cooling of a data center can be optimized to utilize outside air, based upon other ambient conditions such as temperature and humidity.

In accordance with embodiments of the present disclosure, a cooling system is provided to circulate cooling air through IT modules within a large scale information handling system (IHS). In one embodiment, the cooling system includes an air handling unit (AHU) to direct cooling air through one or more IT modules. The cooling system includes an ambient condition interface in communication with an outside contaminant sensor to determine a level of outside contaminants. The cooling system includes a controller in communication with the ambient condition interface and the AHU. The controller performs operations that enable the cooling system to: (i) determine a level of one or more contaminants in the outside air; (ii) determine whether the level of the contaminant(s) exceeds a threshold; and (iii) in response to determining that the level of the contaminant(s) exceeds the threshold, configure the AHU to perform cooling via a mechanical cooling mode that reduces the use of outside air by recirculating air within an IT module via the AHU. Outside air cooling is automatically enabled once the contaminant level does not exceed the threshold and other ambient conditions are favorable to use of outside air to cool the IHS.

According to illustrative embodiments of the present disclosure, a method is provided for circulating cooling air through IT modules within a large scale IHS having an AHU. In one embodiment, the method includes determining a level of a contaminant in outside air. The method includes determining whether the level of the contaminant exceeds a threshold. The method further includes, in response to determining that the level of the contaminant exceeds the threshold, configuring the AHU to perform cooling using a mechanical cooling mode in which the AHU substantially reduces or halts the intake of outside air and perfoms cooling of the IT module utilizing recirculation of air within the IT module. The method also includes automatically configuring the AHU to perform cooling using the outside air when the contaminant level does not exceed the threshold and other ambient conditions are favorable to using outside air to cool the IHS.

The above presents a general summary of several aspects of the disclosure in order to provide a basic understanding of at least some aspects of the disclosure. The above summary contains simplifications, generalizations and omissions of detail and is not intended as a comprehensive description of the claimed subject matter but, rather, is intended to provide a brief overview of some of the functionality associated therewith. The summary is not intended to delineate the scope of the claims, and the summary merely presents some concepts of the disclosure in a general form as a prelude to the more detailed description that follows. Other systems, methods, functionality, features and advantages of the claimed subject matter will be or will become apparent to one with skill in the art upon examination of the following figures and detailed written description.

The present disclosure provides a cooling system that includes an air handling unit (AHU) that circulates cooling air through an information technology (IT) module containing rack-based information handling systems in a closed mode whenever a level of contaminant in outside air exceeds a threshold. The AHU utilizes a normal mode cooling, which includes use of the outside air and limited or no recirculation of air within the data center, when outside temperature and/or humidity are within an acceptable range and the level of contaminant in the outside air does not exceed the threshold. When the level of contaminant is below the theshold, the cooling modes implemented by the cooling system can be based on one or more detected conditions in and around the data center, with a default mode including the use of outside air.

References within the specification to "one embodiment," "an embodiment," "embodiments", or "one or more embodiments" are intended to indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. The appearance of such phrases in various places within the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Further, various features are described which may be exhibited by some embodiments and not by others. Similarly, various requirements are described which may be requirements for some embodiments but not other embodiments.

It is understood that the use of specific component, device and/or parameter names and/or corresponding acronyms thereof, such as those of the executing utility, logic, and/or firmware described herein, are for example only and not meant to imply any limitations on the described embodiments. The embodiments may thus be described with different nomenclature and/or terminology utilized to describe the components, devices, parameters, methods and/or functions herein, without limitation. References to any specific protocol or proprietary name in describing one or more elements, features or concepts of the embodiments are provided solely as examples of one implementation, and such references do not limit the extension of the claimed embodiments to embodiments in which different element, feature, protocol, or concept names are utilized. Thus, each term utilized herein is to be given its broadest interpretation given the context in which that terms is utilized.

<FIG> illustrate a block diagram representation of an example data center <NUM> having a mixed and multi-mode cooling (MMC) system <NUM> that operates to prevent damage to the IT gear inside the data center due to a high level (above respective preset thresholds) of one or more contaminant(s) <NUM> in the outside air. When permissible, based on the presence of only a low level of contaminant <NUM>, the MMC system <NUM> can reduce energy costs by expanding use of outside air for cooling within a hybrid mode operation. Hybrid mode cooling can include the mixed mode that refers to using recirculated air to warm outside air that is otherwise too cold or too humid. The hybrid mode cooling can also include multi-mode cooling, which involves performing mechanical cooling while using outside cooling air, referred to herein as mechanical trimming. The expanded use of outside air includes partial use of outside air even when the outside temperature and the outside humidity are not within an acceptable range for information handling systems (IHSes) <NUM> within an information technology (IT) module <NUM> of the data center <NUM>. In one embodiment, the MMC system <NUM> directly controls an air handling unit (AHU) <NUM> that provides cooling to at least one IT module within modular data center <NUM>. In at least one embodiment, the data center is and/or is configured as an expandable modular Information Technology (IT) Building Infrastructure (EMITBI). Further, because of the relatively large scale of data center and the use of modular building blocks that house the IT gear within the data center, the combination of IT modules that are cooled by the AHUs is collectively referred to herein as modularly-constructed, large-scale information handling system (LIHS) or simply an IHS. Within the general context of IHSes, an information handling system (IHS) <NUM> may include any instrumentality or aggregate of instrumentalities operable to compute, classify, process, transmit, receive, retrieve, originate, switch, store, display, manifest, detect, record, reproduce, handle, or utilize any form of information, intelligence, or data for business, scientific, control, entertainment, or other purposes. For example, an IHS may be a personal computer, a PDA, a consumer electronic device, a network storage device, or any other suitable device and may vary in size, shape, performance, functionality, and price. The IHS may include memory, one or more processing resources such as a central processing unit (CPU) or hardware or software control logic. Additional components or the IHS may include one or more storage devices, one or more communications ports for communicating with external devices as well as various input and output (I/O) devices, such as a keyboard, a mouse, and a video display. The IHS may also include one or more buses operable to transmit communication between the various hardware components. It is appreciated that the IHS described within the present disclosure is a LIHS, with servers acting as the individual processing units.

Data center <NUM> of <FIG> (with top view of some components also illustrated by <FIG>) includes an IT module <NUM> having a row of rack-mounted IHSes <NUM> that separate a cold aisle <NUM> from a hot aisle <NUM>, which is in fluid communication with a hot air return plenum <NUM>. The AHU <NUM> includes a return chamber <NUM> that is in fluid communication with the hot air return plenum <NUM>. The AHU <NUM> includes an exhaust portal, such as, but not limited to, an exhaust chimney <NUM>, which is in in fluid communication with the return chamber <NUM>. The AHU <NUM> includes an intake chamber <NUM> that is fluid communication with the return chamber <NUM> and an outside environment <NUM>. In one embodiment, the exhaust chimney <NUM> mitigates warmed air from being drawn into the intake chamber <NUM>. However, an exhaust portal can a flush mounted, relying on spacing to prevent inadvertent recirculation. It is appreciated that the outside environment encompanses some or all of the exterior of the AHU and data center, and the specific location illustrated within the figure only references one location adjacent/relative to the intake chamber for simplicity in describing the intake process of external air. The AHU <NUM> includes an air mover to move air through the IT module <NUM>. Specifically, The AHU <NUM> includes an outlet chamber <NUM> that is uniform pressurized by an air plenum blower <NUM> driven by a motor <NUM>. The air plenum blower <NUM> pulls air in axially and sprays it our radially within an enclosed space to pressurize evenly. The air plenum blower <NUM> draws air from the intake chamber <NUM> through a contaminant filter <NUM> and a chiller coil <NUM>. The pressurized air in the outlet chamber <NUM> exits the AHU <NUM> and enters the cold aisle <NUM> of the IT module <NUM>.

Performance of the contaminant filter <NUM> can be monitored by an air contamination sensor <NUM> that is internal to the AHU <NUM>. For example, a level of contamination of the outside air can be compared to an internal level of contamination that is measured downstream of the filter <NUM>. The comparison can be used to set the threshold for closing the AHU <NUM>. The comparison can also indicate degradation in the filtering capacity of the filter <NUM>. When the AHU <NUM> is operating in a closed mode, the air contamination sensor <NUM> can indicate contamination originating within the IT module <NUM> that can require remediation.

In one embodiment, a contamination source can be remote from the location of the AHU <NUM>, and monitored by a secondary sensor, which reports (or forwards) a contaminant level reading to the contamination sensor <NUM>. For example the facility hosting the IHS and AHU can be located downstream from a chemical processing plant that can ocassionally produce emissions that are harmful to one or more components of the HIS (e.g. a corrosive emission). A remote sensor (e.g., a municipality sensor) can be located at the chemical plant or at a location that enables detection of the chemical emission heading towards the location of the IHS. The remote sensor can then transmit, either via a wired network or wirelessly, a signal indicating the present of the harmful air-borne emissions, whch signal triggers the contamination sensor <NUM> to cause the AHU to enter into a closed mode. Other examples of such contamination sources include, but are not limited to, forest fires, tordandos, and hurricanes, which each source having a sensor that monitors and reports the presence of harmful ambient conditions that trigger the closed mode of operation by the AHU. In yet another embodiment, a combination of conditions can be utilized in determining when to enter into a closed mode of operation. For example, a low level of contamination may not necessarily trigger the closed mode in dry conditions, while the same level of contiamination, in humid conditions, can result in corrosion or other hamful conditions and thus would require the contamination sensor <NUM> place the AHU in the closed mode.

The AHU <NUM> can be configured for a mode of cooling that is appropriate for the outside ambient conditions. In one or more embodiments, the AHU <NUM> can be configured by the MMC system <NUM> for one of (<NUM>) a normal mode, (<NUM>) a mixed mode, (<NUM>) a mechanical trim mode, and (<NUM>) a closed mode.

<FIG> illustrates the AHU <NUM> having an MMC controller <NUM> that is responsive to air sensing components <NUM>. Air sensing components <NUM> can include, but are not limited to, a humidity sensor <NUM>, a temperature sensor <NUM>, and a gas/liquid/solid contaminant sensor <NUM>. When the air sensing components <NUM> indicate that the ambient temperature of the exterior air is within an acceptable (or normal) range (TN) and that the humidity of the exterior air is also within an acceptable range (HN), the MMC controller <NUM> configures the AHU <NUM> for normal mode cooling, which involves using only the outside air for cooling of the IHSes. An exhaust damper <NUM> is opened between the return chamber <NUM> and the exhaust chimney <NUM> to allow the exhaust air to exit the AHU <NUM>. Simultaneously or concurrently, a recirculation damper <NUM> is closed between the return chamber <NUM> and the intake chamber <NUM> to prevent recirculation of the exhaust air. An outside air intake damper <NUM> is opened, allowing outside air from the outside environment <NUM> to enter the AHU <NUM>. In normal mode, a direct expansion (DX) cooling unit <NUM> that supports the AHU <NUM> remains off.

<FIG>, <FIG>, <FIG>, <FIG> illustrate the DX cooling unit <NUM> having a first compressor <NUM> and a second compressor <NUM> for stepped performance. The compressors <NUM>, <NUM> compress and move compressed (liquid) coolant on a high side from a coolant tank <NUM> through a discharge line <NUM> and through a condenser coil <NUM>. A condenser motor <NUM> drives a condenser fan <NUM> to move condensing air through the condenser coil <NUM>. The condensing air convectively removes heat (generated during the compression) from the coolant. An expansion device (not shown) downstream of the condenser coil <NUM> causes expansion cooling by creating a pressure loss between the high and low sides of the DX cooling unit <NUM>. An evaporator coil <NUM> transfers heat from its ambient environment to the coolant that is then pulled from a suction line <NUM> back to the coolant tank <NUM>. In one embodiment, the DX cooling unit <NUM> is part of a chiller system <NUM> in order to avoid short cycling of the compressor <NUM>. The DX cooling unit <NUM> chills water in an insulated storage tank <NUM> that receives the cooling from the evaporator coil <NUM>. The chiller system <NUM> then includes a heat exchanger <NUM> that includes the chiller coil <NUM> and a heat sink coil <NUM> in the insulated storage tank <NUM>. The MMC controller <NUM> activates a chiller pump <NUM> to move coolant through the chiller coil <NUM> and a heat sink coil <NUM>. The compressor <NUM> can operate for a period of time that is efficient with the insulated storage tank <NUM> supplying an amount of cooling as needed by pumping a determined flow rate. Chiller capacity can be stepwise modulated, such as by turning scroll compressors on and off. In one embodiment, when all of the compressors become engaged per chiller, then the AHU <NUM> can be configured for closed mode.

The DX cooling unit <NUM> can server as a dehumidifier <NUM> that removes moisture as condensate at the chiller coil <NUM>. Thereby, outside humidity value that is above the acceptable range, or would become too high during mechanical trim mode, can be removed. In addition, in one embodiment, the MMC cooling system <NUM> can include a humidifer <NUM> that increases the level of humidity in the moderated outside air by adding moisture.

<FIG> illustrate the air sensing components <NUM> indicating that the level of contaminant <NUM> is acceptably low. The MMC controller <NUM> can respond by optimizing use of outside cooling air based upon temperature and humidity, which in this instance includes an outside temperature value that is lower than acceptable to fall within a mixed range. The MMC controller <NUM> triggers the AHU <NUM> for mixed mode cooling by (i) opening the exhaust damper <NUM>, (ii) modulating the recirculation damper <NUM> as necessary to warm the outside air, and (iii) opening the outside air intake damper <NUM>. In mixed mode, the DX cooling unit <NUM> is off. For mixed mode, the outside environment <NUM> is colder than acceptable for normal mode (TM). Recirculating a portion of the hot exhaust air from the IT module <NUM> warms the outside air to an acceptable temperature. Warming the air in mixed mode reduces the dew point of the resultant cooling air within the AHU <NUM>. Generally this reduction in relative humidity of the outside humidity value (HM) results in a modified humidity value that remains within an acceptable range.

<FIG> illustrate the air sensing components <NUM> indicating that the level of contaminant <NUM> is acceptably low. The MMC controller <NUM> can respond by optimizing use of outside cooling air based upon temperature and humidity, which in this instance is an elevated temperature range and a moderate humidity range that fall within a mechanical trim range. The MMC controller <NUM> triggers the AHU <NUM> for mechanical trim cooling mode by (i) opening the exhaust damper <NUM>, (ii) closing the recirculation damper <NUM>, and (iii) opening the outside air intake damper <NUM>. For mechanical trim mode, the AHU <NUM> realizes power efficiencies of cooling with outside air with some additional cooling provided by the DX cooling unit <NUM> that is operating at a stepped down mode. In addition, the amount of recirculation within the AHU <NUM> can be modulated for purposes such as making the air dryer. The MMC controller <NUM> triggers the mechanical trim mode in response to the outside temperature value (TT) and the outside humidity value (HT) each being within a mechanical trim range. The outside air can be cooled to the acceptable temperature range by the DX cooling unit <NUM>, while maintaining or bringing the humidity within the acceptable humidity range.

<FIG> illustrate the MMC controller <NUM> configuring the AHU <NUM> for closed mode in order to prevent an elevated level of contaminant <NUM> from causing damage to the data center <NUM>. Alternatively, when the level of contaminant <NUM> is acceptably low, the MMC controller <NUM> triggers the AHU <NUM> for closed mode when the temperature temperature value and outside humidity value do not fall within a range that allows for use of outside cooling air. The MMC controller <NUM> triggers the AHU <NUM> for closed mode by (i) closing the exhaust damper <NUM>, (ii) opening the recirculation damper <NUM>, and (iii) closing the outside air intake damper <NUM>. In addition to when the level of contaminant <NUM> is not acceptably low, closed mode is used when the outside ambient conditions (Tc, He) are not conducive to the use of outside air for cooling. For example, the DX cooling unit <NUM> may not have separate stages/compressors that allow for a reduced amount of mechanical cooling suitable for mechanical trim mode. For another example, the outside temperature and/or humidity can be too high for mechanical trim to remove enough heat and/or humidity to reach an acceptable range. When the MMC system <NUM> is operating in the closed mode, the DX cooling unit <NUM> provides all of the cooling necessary to maintain the IT module <NUM> within an acceptable temperature and humidity range.

TABLE <NUM> summarizes the configurations of the AHU <NUM> for the exemplary four (<NUM>) modes of normal mode (<FIG> - IB), mixed mode (<FIG>), mechanical trim mode (<FIG>), and closed mode (<FIG>):.

<FIG> illustrates an example psychometric chart <NUM> of an illustrative mapping of outside temperatures values and outside humidity values for the various cooling modes, from among a normal mode <NUM> that uses only outside air, a mixed mode <NUM>, and a mechanical trim mode <NUM> for three ranges of ambient conditions of temperature and humidity. Mechanical cooling mode <NUM> is used for all three ranges in instances of outside contaminants <NUM>.

<FIG> illustrates an exemplary power and computing environment of an example MMC system <NUM> that configures an AHU <NUM> to efficiently cool an IT module <NUM> of a data center <NUM>. A programmable logic controller (PLC) node ("controller") <NUM> of the MMC system <NUM> communicates via an ambient condition interface <NUM> to outside air sensing components <NUM> to ascertain suitability of using outside air for cooling. For example, the outside air sensing components (or air sensors) <NUM> can include a relative humidity sensor <NUM> and a temperature sensor <NUM>. As shown, the outside air sensing components <NUM> can also include a particulate contaminant sensor <NUM>, a corrosion contaminant sensor <NUM>, and other solid/liquid/gas contaminant sensor <NUM>. Certain outside conditions, including, but not limited to temperature and humidity, can render the outside air unsuitable for direct use, and require the MMC System <NUM> to implement a different mode of cooling.

Turning now to the power aspects and communication aspects of MMC system <NUM>, "A" feed source <NUM> and "B" feed source <NUM> provide electrical power for the MMC system <NUM> via respective fused switches <NUM>, <NUM>. AHU <NUM> receives the "A" and "B" feeds at an automatic transfer switch (ATS) <NUM> in an AHU control panel (CP) <NUM>. ATS <NUM> in turn provides power to the controller <NUM> that activates other components in AHU <NUM>. For example, the controller <NUM> can communicate with an exhaust damper interface <NUM> to activate an exhaust damper <NUM>. The controller <NUM> can communicate with a recirculation damper interface <NUM> to activate a recirculation damper <NUM>. The controller <NUM> can communicate with an outside air intake damper interface <NUM> to activate a recirculation damper <NUM>. The controller <NUM> can communicate with a fan variable frequency drive (VFD) <NUM> that activates an air flow motor <NUM> of an air plenum <NUM>. The controller <NUM> can communicate with a compressor VFD <NUM> that activates a compressor motor <NUM> of an air plenum <NUM>. And, The controller <NUM> can communicate with a condenser VFD <NUM> that activates a condenser motor <NUM> that turns a condenser fan <NUM>.

IT module <NUM> also receives the "A" and "B" feeds at an ATS <NUM> in an IT CP <NUM>. The "A" feed also passes through a PLC control panel terminal (CPT) <NUM> to an uninterruptable power supply (UPS) <NUM> that in turn passes "A" feed to eBus +VDC power supply (PS) <NUM> and to power bus +VDC PS <NUM>. "B" feed is passed to eBus -VDC PS <NUM> and to power bus -VDC PS <NUM>. The eBus +VDC PS <NUM> and eBUS -VDC PS <NUM> provide electrical power through two series redundant modules (RM) <NUM>, <NUM> to an IT PLC <NUM> having a battery backup <NUM> as well as to the controller <NUM> in the AHU <NUM> that monitors eBus status. The IT PLC <NUM> also communicates with controller <NUM> to indicate data from load sensing components <NUM>. Power bus +VDC PS <NUM> and eBUS -VDC PS <NUM> provide electrical power through two series RMs <NUM>, <NUM> to the IT PLC <NUM> and to the controller <NUM>. An output of the IT ATS <NUM> passes through an emergency power off (EPO) CPT <NUM> to a UPS <NUM> of an EPO panel <NUM>. The output of the IT ATS <NUM> also passes through a utility CPT <NUM> to lighting and power outlets <NUM>.

Increasing the use of outside air was shown by deterministic analysis to provide substantial power savings for several illustrative locations as detailed in the following table. TABLE <NUM> provides outside conditions for Santiago, Chile (<NUM> year average values for each mode are used in power usage efficiency (PUE) calculation):.

<FIG> illustrates a method <NUM> for cooling IT modules within a large scale IHS having an AHU. In one embodiment, the method <NUM> includes filtering air in the AHU to remove at least a portion of the contaminant (block <NUM>). The contaminant can be gaseous, liquid or solid particles. The contaminant can also be corrosive. It is appreciated that the contaminant is dependent on the location of the data center, and that the specific locations may have more than one contaminant that require monitoring. That is, in one or more embodiments, the contaminant can comprise more than one material. The method <NUM> includes determining the threshold based at least in part on a determined effectiveness of the filtering of the portion of the contaminant (block <NUM>). The method <NUM> further includes determining a level of a contaminant in outside air (block <NUM>). For environments having more than one contaminant, each contaminant can have a different threshold. The method <NUM> includes determining whether the level of the specific contaminant exceeds the corresponding threshold established for that contaminant (decision block <NUM>). In response to determining that the level of the contaminant exceeds the threshold in decision block <NUM>, the method <NUM> includes configuring the AHU to perform cooling using a mechanical cooling mode that closes the cooling system off from the outside air (to prevent or substiantially reduce the exposure of the IT gear to the contaminant) and performs cooling by recirculating air within an IT module via the AHU (block <NUM>). In response to determining that the level of the contaminant does not exceed the threshold in decision block <NUM>, the method <NUM> further determines whether other ambient conditions are favorable for using outside air to cool the IT module (decision block <NUM>). In response to determining in decision block <NUM> that the other ambient conditions are favorable for using outside air, the method <NUM> includes configuring the AHU to use outside air for cooling the IT module (block <NUM>). In response to determining in decision block <NUM> that the other ambient conditions are favorable for using outside air, the method <NUM> includes configuring the AHU to use outside air for mechanical cooling nide that is closed to the other ambient conditions of the outside air by recirculating air within the IT module (block <NUM>). After either of blocks <NUM>, <NUM>, and <NUM>, the method <NUM> returns to block <NUM> to dynamically monitor and to respond to ambient conditions.

<FIG> illustrate an exemplary method <NUM> of cooling a data center, and more particularly an Expandable Modular Rack-Housing Building Infrastructure (EMRBI), that is responsive to environmental conditions to prevent contaminants from causing damage to the IT modules within the data center. To the extent permissible by a level of contaminant in outside air, the method <NUM> provides for cooling the data center with outside air for greater economy in an expanded range of temperatures and humidity, according to one embodiment. With initial reference to <FIG>, the method <NUM> begins at start block. The controller determines a level of contaminant in outside air (block <NUM>). The contaminant can be a substance, compound, material, etc., that has a negative effect on or more IT components with the IHS. The negative effect can include corrosion. The contaminant can be gaseous, liquid or a solid particulate matter. In one embodiment, the controller measures a level respectively of more than one contaminant, each associated with a different threshold for rendering cooling air acceptable for use in the data center. In one embodiment, the AHU includes one or more filters that filter a portion of the one or more types of contaminants from the outside air that is pulled into the AHU for cooling air. Controller can determine a maximum threshold of contaminant in the outside air based upon the efficacy of filtering of the contaminant. The efficacy can be determined based on a preset value, a deterministic changing value based upon monitoring usage of filtering material, or can be dynamically sensed downstream of the filter (block <NUM>).

The controller determines whether the level of the contaminant in the outside air exceeds the threshold (block <NUM>). In response to determining in decision block <NUM> that the level of contaminant exceeds the threshold, method <NUM> can further include the controller determining that mechanical cooling mode is warranted (decision block <NUM>). In particular, the method <NUM> includes the controller fully opening the recirculation damper between the hot air return plenum and the intake air chamber (block <NUM>). The controller closes the outside air intake damper at the outside air intake to the intake air chamber (block <NUM>). The controller closes the exhaust damper between the hot air return plenum and an exhaust chimney (block <NUM>). The controller activates the direct expansion cooling unit that has the expansion unit within the intake air chamber. In one embodiment, the controller activates less than all of the compressors available of a direct expansion cooling unit that cool a chiller system (block <NUM>). The controller activates the motor-driven air plenum to draw air from the hot air plenum into the intake air chamber to the cold aisle of the IT module, and the air then passes through the rack-mounted IHSes to the hot aisle of the IT module and ultimately to the hot air return plenum for full recirculation (block <NUM>). The method <NUM> then returns to block <NUM> to dynamically monitor outside conditions in order to select an appropriate cooling mode. In response to determining in decision block <NUM> that the level of contaminant in outside air does not exceed the threshold, method <NUM> proceeds to block <NUM> (<FIG>).

Continuing in <FIG>, the method <NUM> includes the controller determining an outside temperature value (block <NUM>). The controller determines an outside humidity value (block <NUM>). The controller can then determine whether the outside temperature value is within an acceptable temperature range and whether and the outside humidity value is within an acceptable humidity range for normal mode (decision block <NUM>). In response to determining that both that the outside temperature value is within the acceptable temperature range and that the outside humidity value is within the acceptable humidity range, the controller triggers an AHU to perform the normal mode of outside air cooling of an IT module containing rack-mounted IHSes (block <NUM>). In particular, the controller closes a recirculation damper between a hot air return plenum and an intake air chamber (block <NUM>). The controller opens an outside air intake damper at an outside air intake to the intake air chamber (block <NUM>). The controller opens an exhaust damper between the hot air return plenum and an exhaust chimney (block <NUM>). The controller activates a motor-driven air plenum to draw air through the IT module. In particular, the air is drawn from the intake air chamber to a cold aisle of the IT module that in turn passes air through the rack-mounted IHSes to a hot aisle of the IT module and ultimately to the hot air return plenum for exhausting out of the exhaust chimney (block <NUM>). The method <NUM> returns to block <NUM> (<FIG>) to dynamically monitor outside conditions in order to select an appropriate mode.

In response to determining in decision block <NUM> that one of the outside temperature value and the outside humidity value is not in a range for normal mode cooling, the controller makes a further determination as to whether the outside temperature value is below the acceptable temperature range, while the outside humidity value is within the acceptable humidity range for cooling via mixed mode (decision block <NUM>). In response to the determination in decision block <NUM> that at least one (or the combianiton of) the outside temperature value and outside humidity value are in the range pre-identified to trigger mixed mode cooling, controller triggers the AHU to cool the IT module by implementing the mixed mode cooling (block <NUM>). In particular, the controller partially opens the recirculation damper between the hot air return plenum and the air intake chamber (block <NUM>). In one embodiment, the amount that the recirculation damper is opened is modulated in relation to the amount of heating of the outside air required to maintain an acceptable temperature range within the IT module. In one embodiment, a themostat is utilized to track the temperature of the air inside the AHU. The thermostat is communicatively connected to the controller to provide real time termperature readings of the cooling air and moderated air. The controller opens the outside air intake damper at the outside air intake to the air intake chamber (block <NUM>). The controller opens the exhaust damper between the hot air return plenum and the exhaust chimney (block <NUM>). The controller activates the motor-driven air plenum blower to draw air through the IT module. In particular, the air is drawn from the air intake chamber to the cold aisle of the IT module and the air in turn passes through the rack-mounted IHSes to the hot aisle of the IT module and ultimately to the hot air return plenum for partially exhausting out of the exhaust portal and partially recirculating (block <NUM>). The method <NUM> then returns to block <NUM> (<FIG>) to dynamically monitor outside conditions in order to select an appropriate mode.

In response to determining in decision block <NUM> that at least one (or both of) the outside temperature value and the outside humidity value are not in a range for mixed mode cooling, method moves to <FIG>, which includes the controller determining whether at least one of the outside temperature value and the outside humidity value is within a range for mechanical trim mode cooling (decision block <NUM>). Mechanical trim mode relies on mechanical cooling in combination with outside air cooling. When in mechanical trim mode, The outside temperature value and outside humidity value are within a certain range that allows for a stepped down performance level of a direct expansion cooling unit in combination with outside air to be satisfactory. The outside humidity value is below a maximum humidity threshold such that cooling of the outside air will not result in moderated air that has a humidity level above what is acceptable for the IT module. In response to the determination in decision block <NUM> that the outside temperature value and the outside humidity value are within a range for implementing the mechanical trim mode, the controller triggers the AHU for mechanical trim mode cooling and cools outside air with mechanically cooling (block <NUM>). In particular, the method <NUM> includes the controller closing the recirculation damper between the hot air return plenum and the air intake chamber (block <NUM>). The controller opens the outside air intake damper at the outside air intake to the air intake chamber (block <NUM>). The controller opens the exhaust damper between the hot air return plenum and an exhaust portal (block <NUM>). The controller activates at least a portion of the direct expansion cooling unit that has an expansion unit with the air intake chamber. (block <NUM>). The controller activates the motor-driven air plenum blower to draw air from the air intake chamber to the cold aisle of the IT module that in turn passes air through the rack-mounted IHSes to a hot aisle of the IT module and ultimately to the hot air return plenum for exhausting out of the exhaust portal (block <NUM>). The method <NUM> then returns to block <NUM> (<FIG>) to continue dynamically monitoring outside air conditions in order to select an appropriate cooling mode.

In response to determining in decision block <NUM> that the outside temperature value and the outside humidity value are not in a range for mechanical trim mode, <FIG> illustrates that the method <NUM> can further include the controller determining whether the outside temperature value and the outside humidity value are within a range for mechanical cooling mode (decision block <NUM>). In particular, the method <NUM> includes the controller fully opening the recirculation damper between the hot air return plenum and the air intake chamber (block <NUM>). The controller closes the outside air intake damper at the outside air intake to the air intake chamber (block <NUM>). The controller closes the exhaust damper between the hot air return plenum and an exhaust chimney (block <NUM>). The controller activates the direct expansion cooling unit to cool the air drawn into the air intake chamber. In one embodiment, the controller activates less than all of the compressors available of a direct expansion cooling unit that cool a chiller system (block <NUM>). The controller activates the motor-driven air plenum blower to draw air from the hot air plenum into the air intake chamber. The motor-driven air plenum blower pushes the moderated air into the cold aisle of the IT module. The air then passes air through the rack-mounted IHSes to the hot aisle of the IT module. The warmed air then returns to the hot air return plenum for full recirculation (block <NUM>). The method <NUM> then returns to block <NUM> (<FIG>) to dynamically monitor outside conditions in order to select an appropriate mode. In response to determining in decision block <NUM> that the outside temperature value and the outside humidity value are not in a range for mechanical cooling mode, <FIG> illustrates that the method <NUM> ends. In one embodiment, the controller can perform error handling for encountering a temperature range for which there is not a defined cooling configuration of the AHU. It is important to note that none of the cooling modes that involve use of outside air are made available to the cooling system once the level of contaminants within the outside air reaches or surpasses the corresponding threshold for that contaminant.

The cooling system can be part of an Expandable Modular Information Technology (IT) Building Infrastructure (EMITBI) that supports a large-scale modularly-constructed information handling system (LMIHS). In one embodiment, a large compute pad/building structure has interior white space for racks and exterior walls that are designed to enable modular expansion of the structure by extending the build pad, constructing a second external wall, installing the additional IT gear in the extended white space, and then removing the previous exterior wall to create larger overall computer system without disrupting the IT gear, which remains operational during the expansion process; A scaled approach is provided to add devices and redundancy while physically expanding a data center (footprint) using pre-fabricated IT modules for cooling, power, and white space for future IT placement. An external wall can be added to a cold aisle module. Materials for modular walls can be lightweight composite fiber, metal panel with fiberglass insulation, structural foam panel, etc., with sound proofing considerations. The modular walls can provide mounting surfaces for sensors, etc. In one embodiment, the EMITBI includes dedicated hot and cold IT modules that are expandable. AHUs can sit on top of the structure for limited ground space applications or on one or two sides of the white space. AHUs can be added as needed when expansion occurs.

The cooling system can be part of configurable modular data center. Each of the modules may be dedicated to one of the primary elements of a data center, such as fluid handling, computing and power. Each of the plurality of modules may be separately configurable, according, at least in part, to operational and environmental requirements for the modular data center. The plurality of modules may then be incorporated into at least one modular data center structure, whose size and shape will depend, at least in part, on the configuration of each of the plurality of modules. One advantage is in escaping the design constraints of an existing containerized data center integrated into an International Organization for Standardization (ISO) shipping container. Breaking design elements into separately configurable modules generally removes the space limitations of an existing containerized data center.

In the above described flow charts of <FIG> and <FIG>, one or more of the methods may be embodied in an automated controller of a cooling system that performs a series of functional processes.

One or more of the embodiments of the disclosure described can be implementable, at least in part, using a software-controlled programmable processing device, such as a microprocessor, digital signal processor or other processing device, data processing apparatus or system. Thus, it is appreciated that a computer program for configuring a programmable device, apparatus or system to implement the foregoing described methods is envisaged as an aspect of the present disclosure. The computer program may be embodied as source code or undergo compilation for implementation on a processing device, apparatus, or system. Suitably, the computer program is stored on a carrier device in machine or device readable form, for example in solid-state memory, magnetic memory such as disk or tape, optically or magneto-optically readable memory such as compact disk or digital versatile disk, flash memory, etc. The processing device, apparatus or system utilizes the program or a part thereof to configure the processing device, apparatus, or system for operation.

While the disclosure has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the disclosure. In addition, many modifications may be made to adapt a particular system, device or component thereof to the teachings of the disclosure without departing from the essential scope thereof. Therefore, it is intended that the disclosure not be limited to the particular embodiments disclosed for carrying out this disclosure, but that the disclosure will include all embodiments falling within the scope of the appended claims. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another.

Claim 1:
A cooling system (<NUM>) configured to circulate cooling air through information technology, IT, modules within a large scale information handling system, IHS, the cooling system (<NUM>) comprising:
an air handling unit, AHU, (<NUM>) configured to direct cooling air through an IT module, the AHU (<NUM>) further comprising:
a direct expansion cooling unit (<NUM>) to cool air in the AHU (<NUM>);
a hot air return plenum (<NUM>) in fluid communication with a hot aisle (<NUM>) of the IT module and having an exhaust portal;
an air intake chamber (<NUM>) in fluid communication with the hot air return plenum (<NUM>) and having an air intake and air outlet;
an outlet chamber (<NUM>) in fluid communication with the air intake chamber (<NUM>) via the air outlet and adapted to be in communication with a cold aisle (<NUM>) of the IT module;
a recirculation damper (<NUM>) between the hot air return plenum (<NUM>) and the air intake chamber (<NUM>);
an outside air intake damper (<NUM>) between the outside air intake and the air intake chamber (<NUM>);
an exhaust damper (<NUM>) between the hot air return plenum (<NUM>) and the exhaust portal; and
an air mover positioned and adapted to to move air from the outlet chamber (<NUM>) to the cold aisle (<NUM>) of the IT module;
an ambient condition interface (<NUM>) in communication with at least one outside contamination sensor (<NUM>) configured to determine a level of a contaminant in outside air;
a controller (<NUM>) in communication with the ambient condition interface and the AHU, the controller (<NUM>) being configured to cause the cooling system (<NUM>) to:
determine a level of a contaminant in the outside air;
determine whether the level of the contaminant exceeds a threshold; and
in response to determining that the level of the contaminant exceeds the threshold, trigger the AHU (<NUM>) to perform cooling via a mechanical cooling mode (<NUM>) that includes closing an intake for outside air into the AHU (<NUM>) and recirculating air within an IT module via the AHU (<NUM>) by opening the recirculation damper (<NUM>), closing the exhaust damper (<NUM>), closing the outside air intake damper (<NUM>), activating the air mover, and activating the direct expansion cooling unit (<NUM>); and
in response to the level of contaminants not exceeding the threshold and other detected ambient conditions are favorable to using outside air to cool the IHS, configuring the AHU (<NUM>) to perform cooling using the outside air.