Patent Publication Number: US-10765037-B2

Title: Vertical exhaust duct for electronic equipment enclosure

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a U.S. continuation patent application of, and claims priority under 35 U.S.C. § 120 to, U.S. nonprovisional patent application Ser. No. 16/450,353, filed Jun. 24, 2019, which &#39;353 application published as U.S. Patent Application Publication No. US 2019/0313551 A1 on Oct. 10, 2019, which &#39;353 application issued as U.S. Pat. No. 10,568,239 on Feb. 18, 2020, which &#39;353 application, the application publication thereof, and the patent issuing therefrom are each expressly incorporated herein by reference in their entirety, and which &#39;353 application is a U.S. continuation patent application of, and claims priority under 35 U.S.C. § 120 to, U.S. nonprovisional patent application Ser. No. 16/180,677, filed Nov. 5, 2018, which &#39;677 application published as U.S. Patent Application Publication No. US 2019/0075685 A1 on Mar. 7, 2019, which &#39;677 application issued as U.S. Pat. No. 10,334,761 on Jun. 25, 2019, which &#39;677 application, the application publication thereof, and the patent issuing therefrom are each expressly incorporated herein by reference in their entirety, and which &#39;677 application is a U.S. continuation patent application of, and claims priority under 35 U.S.C. § 120 to, U.S. nonprovisional patent application Ser. No. 15/784,751, filed Oct. 16, 2017, which &#39;751 application published as U.S. Patent Application Publication No. US 2018/0042143 A1 on Feb. 8, 2018, which &#39;751 application issued as U.S. Pat. No. 10,123,462 on Nov. 6, 2018, which &#39;751 application, the application publication thereof, and the patent issuing therefrom are each expressly incorporated herein by reference in their entirety, and which &#39;751 application is a U.S. continuation patent application of, and claims priority under 35 U.S.C. § 120 to, U.S. nonprovisional patent application Ser. No. 14/822,126, filed Aug. 10, 2015, which &#39;126 application published as U.S. Patent Application Publication No. US 2015/0351289 A1 on Dec. 3, 2015, which &#39;126 application issued as U.S. Pat. No. 9,801,309 on Oct. 24, 2017, which &#39;126 application, the application publication thereof, and the patent issuing therefrom are each expressly incorporated herein by reference in their entirety, and which &#39;126 application is a U.S. continuation patent application of, and claims priority under 35 U.S.C. § 120 to, U.S. nonprovisional patent application Ser. No. 14/286,335, filed May 23, 2014, which &#39;335 application published as U.S. Patent Application Publication No. US 2014/0334099 A1 on Nov. 13, 2014, which &#39;335 application issued as U.S. Pat. No. 9,119,329 on Aug. 25, 2015, which &#39;335 application, the application publication thereof, and the patent issuing therefrom are each expressly incorporated herein by reference in their entirety, and which &#39;335 application is a U.S. continuation patent application of, and claims priority under 35 U.S.C. § 120 to, U.S. nonprovisional patent application Ser. No. 13/348,820, filed Jan. 12, 2012, which &#39;820 application published as U.S. Patent Application Publication No. US 2012/0194999 A1 on Aug. 2, 2012, which &#39;820 application issued as U.S. Pat. No. 8,737,068 on May 27, 2014, which &#39;820 application, the application publication thereof, and the patent issuing therefrom are each expressly incorporated herein by reference in their entirety, and which &#39;820 application is a U.S. continuation patent application of, and claims priority under 35 U.S.C. § 120 to, U.S. nonprovisional patent application Ser. No. 12/555,697, filed Sep. 8, 2009, which &#39;697 application published as U.S. Patent Application Publication No. US 2010/0061059 A1 on Mar. 11, 2010, which &#39;697 application issued as U.S. Pat. No. 8,107,238 on Jan. 31, 2012, which &#39;697 application, the application publication thereof, and the patent issuing therefrom are each expressly incorporated herein by reference in their entirety, and which &#39;697 application is:
         (a) a continuation-in-part patent application of, and claims priority under 35 U.S.C. § 120 to, U.S. nonprovisional patent application Ser. No. 11/533,359, filed Sep. 19, 2006, which &#39;359 application published as U.S. Patent Application Publication No. US 2007/0064389 A1 on Mar. 22, 2007, which &#39;359 application and the application publication thereof are each expressly incorporated herein by reference in their entirety, and which &#39;359 application is a U.S. nonprovisional patent application of, and claims priority under 35 U.S.C. § 119(e) to, U.S. provisional patent application Ser. No. 60/718,548, filed Sep. 19, 2005, which &#39;548 application is expressly incorporated herein by reference in its entirety; and   (b) a U.S. nonprovisional patent application of, and claims priority under 35 U.S.C. § 119(e) to, U.S. provisional patent application Ser. No. 61/095,147, filed Sep. 8, 2008 which &#39;147 application is expressly incorporated herein by reference in its entirety.       

    
    
     COPYRIGHT STATEMENT 
     All of the material in this patent document is subject to copyright protection under the copyright laws of the United States and of other countries. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. 
     BACKGROUND OF THE PRESENT INVENTION 
     Field of the Present Invention 
     The present invention relates generally to cabinets for rack-mount computer and data storage equipment, and, in particular, to thermal management of cabinets for rack-mount computer and data storage equipment. 
     Background 
     Racks, frames and cabinets for mounting and storing computer and other electronic components or equipment have been well known for many years. Racks and frames are typically simple rectangular frameworks on which electronic components may be mounted, or on which other mounting members, such as shelves or brackets, may be mounted which in turn may support the electronic components. Cabinets are typically frames on which panels or doors, or both, are hung to provide aesthetic improvement, to protect the components from external influences, to provide security for the components stored inside, or for other reasons. 
     Racks, frames and cabinets have been built in many different sizes and with many different proportions in order to best accommodate the components which they are designed to store. Components stored in these enclosures may include audio and video equipment and the like, but quite frequently include computer equipment and related peripheral devices. These components typically include housings enclosing internal operative elements. 
     As is also well known, the electronic equipment mounted therein tends to generate large amounts of thermal energy that needs to be exhausted away from the equipment effectively in order to maintain the equipment in proper operating order or to prevent damage thereto. The problem can be especially significant when the components are enclosed in cabinets, because thermal energy generated thereby can concentrate within the equipment enclosure and cause the components to overheat and shut down. As equipment becomes more densely packed with electronics, the quantities of thermal energy have continued to increase in recent years, and thermal energy management has become a significant issue confronting today&#39;s rack, cabinet, frame and enclosure manufacturers, the manufacturers of the electronic equipment, and the users of such equipment. 
     Typically, multiple racks, frames, cabinets, and the like (sometimes collectively referred to hereinafter as “enclosures”) are housed together in a data center. Because of the overheating problem, and particularly with multiple enclosures being placed in a single room or other enclosed space, thermal management of the data center is very important. A goal of data center thermal management is to maximize the performance, uptime and life expectancy of the active components being housed in the data center. This goal is generally accomplished by managing the cold air delivered to each component such that the internal temperature of the component does not exceed the manufacturer&#39;s maximum allowable operating temperature. Preferably, the cold air delivered to the component is at or below the manufacturer&#39;s recommended temperature and in sufficient volume to meet the airflow requirements of the component, which are typically measured in cubic feet per minute (CFM). 
     A common type of operating environment for enclosures and the equipment mounted therein is known as a “raised floor” system, wherein the enclosures are supported on a heavy-duty mechanical floor that is installed above the actual floor of the room at a given elevation. One significant advantage of this approach is that cables, wires, water pipes, and other utility connections may be routed to and from the enclosures via the space beneath the floor, thereby leaving the top surface of the raised floor clear for locating enclosures and traversal by users. Another significant advantage, however, is that the space beneath the top surface of the raised floor serves as a plenum through which cool air may likewise be distributed to the enclosures. Through open tiles or perforations or ventilations in the tiles comprising the surface of the raised floor, this cool air may be supplied to the enclosures and used to cool the equipment inside. 
     Unfortunately, the use of perforated floor tiles, typically located directly in front of enclosures to try to cause a maximum amount of cool air to be directed into the enclosures and not merely lost to the ambient room, have been found to be insufficient in cooling the equipment within the enclosures to the desired degree. Thus, a number of techniques and devices have been developed in recent years to more efficiently utilize the capabilities of the Computer Room Air Conditioner (“CRAC”) and to put the available cool air to the most efficient use possible. Among others, these include improved strategies involving perforated panels, such as those described in the commonly-assigned U.S. Provisional Patent Application No. 60/725,511, filed Oct. 10, 2005 and entitled “EFFICIENT USE OF PERFORATED PANELS IN ELECTRONIC EQUIPMENT CABINETS,” and also improved cool air distribution strategies, such as those described in the commonly-assigned U.S. Provisional Patent Application No. 60/743,148, filed Jan. 20, 2006 and entitled “INTERNAL AIR DUCT,” the entirety of each of which is incorporated herein by reference. 
     The supply of cool air to the raised floor plenum, and the transfer of thermal energy from the electronic equipment, is conventionally handled by the CRAC. Airflow through the plenum and into the enclosures generally relies solely or at least primarily on the air pressure differential as measured between the raised floor plenum and the ambient room. However, active means are often used to push or pull heated air out of the enclosures. 
     For a particular component, thermal energy is transferred from its housing using forced air convection. More specifically, internal fans draw or push air through the housing from front-to-rear over the heated internal elements within the housing. The air absorbs the thermal energy from the internal elements and carries it away as it exits the housing. 
     Airflow through a particular component housing is primarily controlled by the internal fan installed by the manufacturer. While it is possible to reduce this throughput by constricting air flow through an enclosure, it is difficult to appreciably increase the airflow through a component housing. 
     In addition, the rate of transfer of thermal energy from the housing does not change very much for different intake air temperatures. Lowering the intake air temperature reduces the temperature of the processor(s) inside of the component, but the temperature change and the total cooling taking place for the component does not change for a constant airflow. Therefore, any enclosure that does not choke the airflow through the component mounted inside and that prevents recirculation should effectively dissipate most, if not all, of the thermal energy generated by the component. 
     Recent conventional thinking for the thermal management of data centers involves the use of an approach commonly referred to as the Hot Aisle/Cold Aisle approach. In this strategy, cold air aisles are segregated from hot air aisles by enclosures being positioned between them such that cold air aisles are in front of rows of enclosures and hot air aisles are behind these rows of enclosures. In this approach, the cold air and hot air aisles alternate. Ideally, air enters the enclosure from the cold air aisles and is exhausted from the enclosure into the hot air aisles. 
     This approach works well in low to medium density data center applications. However, it does not perform well in many medium density applications and can not support high density applications without extreme discipline and additional air flow management devices outside of the enclosures to prevent hot exhaust recirculation into the cold aisle. 
     Further, Hot Aisle/Cold Aisle data center environments typically do not operate at ideal conditions. Two common problems that affect thermal management in general, and Hot Aisle/Cold Aisle in particular, are recirculation and bypass. Recirculation occurs when hot exhaust air travels back into the component intake air stream. Recirculation can occur for a single component or for an entire enclosure. When this occurs, the exhaust airflow raises intake air temperatures and causes components to run at higher operating temperatures. Bypass occurs when cold source air bypasses the active component and travels directly into the hot exhaust air stream. Similarly to recirculation, bypass may occur for a single component or for a whole enclosure. Because cold source air is bypassing the active component, the air is not serving its intended purpose of transferring thermal energy away from the active component. As such, the bypassing air is essentially wasted, and the active component retains its thermal energy until additional cold source air contacts the active component thereby transferring the thermal energy away from the component. Based on the foregoing, it is readily apparent that bypass wastes energy. In addition, bypass contributes to humidity control problems, and can indirectly contribute to recirculation. Under ideal circumstances, all recirculation and bypass airflow can be eliminated. 
     Hot Aisle/Cold Aisle is a well-principled thermal management approach, i.e., segregating the cold source air in front of enclosures and hot exhaust air behind them does work. Unfortunately, maintaining the segregation is difficult. In order to maintain proper segregation, the airflow delivered to each enclosure must roughly equal the airflow required by all of the active components in each enclosure. In addition, strict discipline and careful airflow balancing are required to maintain this ideal operating condition in higher density data center environments. While an initial installation may realize these ideal conditions, moves, adds and changes, along with the demands for constantly monitoring and rebalancing, frequently make maintaining this ideal operating condition impractical, if not outright impossible. 
     For example, one known airflow balancing technique employs variable speed fans that are carefully monitored and controlled using appropriate control methodologies. A drawback to the controlled variable speed fan approach is the unpredictable nature of components, particularly server usage. For example if a server is suddenly heavily burdened by a particular software application, the server heats up, perhaps more quickly than expected, or more than can be handled quickly by a corresponding variable fan. The fan then quickly increases in speed in an attempt to respond to the sudden drastic increase in temperature of the server. The fan may not be able to sufficiently supply cooling air to the suddenly overheated server, and even if it is, such heat balancing procedure is difficult, at best, to manage. It would be better to avoid dependence on such a reactive approach to thermal management. 
     Cylindrical exhaust ducts have been added to enclosures in an effort to alleviate thermal management issues such as recirculation and bypass. The exhaust ducts generally extend upwardly away from a top surface of the enclosure near the rear of the enclosure and provide a path for hot exhaust air to be expelled. While available exhaust ducts are operative for their intended purpose, an improved design thereof would further aid in alleviating thermal management issues. In addition, it has been found that heated air tends to pool or collect in portions of the interior of enclosures rather than be guided to the exhaust ducts. 
     As such, a need exists for an improved design of exhaust ducts for component storage enclosures. Further, additional thermal management features are needed in these enclosures. This, and other needs, are addressed by one or more aspects of the present invention. 
     SUMMARY OF THE PRESENT INVENTION 
     The present invention includes many aspects and features. Moreover, while many aspects and features relate to, and are described in, the context of enclosures for storage of electronic equipment, the present invention is not limited to use only in enclosures for storage of electronic equipment, as will become apparent from the following summaries and detailed descriptions of aspects, features, and one or more embodiments of the present invention. 
     Broadly defined, the present invention according to one aspect includes an electronic equipment enclosure comprising a frame structure formed from a plurality of support posts and at least partially enclosed by a plurality of panels. The panels include at least side, top and back panels defining an enclosure having a top, a bottom and a rear thereof. The top panel includes an opening there through that is rectangular in shape. The equipment enclosure further comprises an exhaust air duct extending upward from the top panel of the enclosure. The exhaust air duct is rectangular in cross-section and is disposed in surrounding relation to, and in fluid communication with, the top panel opening. The exhaust air duct is adapted to segregate hot air being exhausted from the enclosure from cool air entering the enclosure, thereby improving thermal management of the enclosure. 
     In a feature of this aspect, the top panel opening is disposed toward the rear of the top panel. In accordance with this feature, the top panel opening is disposed substantially adjacent the back panel of the enclosure. With regard to this feature, the dimensions of the rectangular cross-section of the exhaust air duct are substantially similar to the dimensions of the top panel opening. 
     In another feature, the top panel opening is disposed toward the rear of the enclosure. In an additional feature, the exhaust air duct is self-supporting. In yet another feature, the exhaust air duct is adapted to be connected to a separate overhead structure in a room. With regard to this feature, the exhaust air duct is adapted to be connected to a return air duct. With further regard to this feature, the exhaust air duct has a top edge and a mounting flange extending around the periphery of the top edge for connection to a separate overhead structure in a room. 
     In yet another feature, the height of the exhaust air duct is adjustable, thereby adjusting the distance to which the exhaust air duct extends above the top panel of the enclosure. With regard to this feature, the exhaust air duct includes a first rectangular open-ended duct section that nests inside a second rectangular open-ended duct section, wherein the first duct section may be telescopically withdrawn from the second duct section. 
     In a further feature, the back panel is generally air-impervious to prevent heated air from escaping there through. In accordance with this feature, the back panel is a door panel that is connected at a connection point to the frame structure. Seals are disposed at the connection point between the back door panel and the frame structure. In furtherance of this feature, the seals are brackets. With regard to this feature, the seals are metal. It is preferred that rubber or foam gaskets are included with the seals. 
     In an additional feature, the plurality of panels includes a bottom panel that has a brush opening arranged therein. 
     Broadly defined, the present invention according to another aspect includes an electronic equipment enclosure comprising a frame structure formed from a plurality of support posts and at least partially enclosed by a plurality of panels. The panels include at least side, top and back panels defining an enclosure having a top, a bottom and a rear thereof. The top panel includes an opening there through. The equipment enclosure further comprises an exhaust air duct extending upward from the top panel of the enclosure. The exhaust air duct is disposed in generally surrounding relation to, and in fluid communication with, the top panel opening. The enclosure further comprises an air diverter, disposed near the rear of the enclosure and angled upward to redirect, toward the top of the enclosure, heated air moving rearward through the enclosure. The exhaust air duct and the air diverter cooperate to segregate hot air being exhausted from the enclosure from cool air entering the enclosure, thereby improving thermal management of the enclosure. 
     In a feature of this aspect, the top panel opening is rectangular in shape. In another feature, the top panel opening is disposed toward the rear of the top panel. In an additional feature, the top panel opening is disposed substantially adjacent the back panel of the enclosure. In accordance with this feature, the exhaust air duct is rectangular in cross-section, and the dimensions of the rectangular cross-section of the exhaust air duct are substantially similar to the dimensions of the top panel opening. 
     In yet another feature, the top panel opening is disposed toward the rear of the enclosure. In a further feature, the exhaust air duct is self-supporting. In still a further feature, the exhaust air duct is adapted to be connected to a separate overhead structure in a room. In accordance with this feature, the exhaust air duct is adapted to be connected to a return air duct. With further regard to this feature, the exhaust air duct has a top edge and a mounting flange extending around the periphery of the top edge for connection to a separate overhead structure in a room. 
     In an additional feature, the height of the exhaust air duct is adjustable, thereby adjusting the distance to which the exhaust air duct extends above the top panel of the enclosure. In furtherance of this feature, the exhaust air duct includes a first rectangular open-ended duct section that nests inside a second rectangular open-ended duct section, wherein the first duct section may be withdrawn from the second duct section by a predetermined amount. 
     In another feature, the back panel is generally air-impervious to prevent heated air from escaping there through. With regard to this feature, the back panel is a door panel that is connected at a connection point to the frame structure. Seals are disposed at the connection point between the back door panel and the frame structure. With further regard to this feature, the seals are brackets. It is preferred that the seals are metal. It is further preferred that rubber or foam gaskets are included with the seals. 
     In still yet another feature, the plurality of panels includes a bottom panel that has a brush opening arranged therein. 
     Broadly defined, the present invention according to yet another aspect includes an exhaust air duct adapted to segregate hot air being exhausted from an electronic equipment enclosure from cool air entering the enclosure, thereby improving thermal management of the enclosure, wherein the exhaust air duct includes four panels joined at side edges thereof to form a rectangular shaped exhaust duct. Each of at least two of the panels has a flange at a bottom edge thereof such that the exhaust air duct has a flange around a bottom periphery thereof. 
     In a feature of this aspect, each of all four of the panels has a flange at a bottom edge such that the exhaust air duct has a flange around a bottom periphery thereof. In another feature, the panels are constructed of a material that is self-supporting. In yet another feature, an upper end thereof is adapted to be connected to a separate overhead structure in a room. In accordance with this feature, the upper end thereof is adapted to be connected to a return air duct. With regard to this feature, the upper end thereof has a top edge and a mounting flange extending around the periphery of the top edge for connection to a separate overhead structure in a room. 
     In an additional feature, the height of the exhaust air duct is adjustable, thereby adjusting the distance to which the exhaust air duct extends above the top panel of the enclosure. With regard to this feature, the exhaust air duct includes a first rectangular open-ended duct section that nests inside a second rectangular open-ended duct section, wherein the first duct section may be telescopically withdrawn from the second duct section. In accordance with this feature, the telescopically withdrawn duct section is self-supporting. Further in accordance with this feature, the telescopically withdrawn duct section may be affixed to the second duct section at a user-controlled vertical disposition relative to the second duct section. It is preferred that at least one of the duct sections includes a plurality of columns of evenly-spaced openings adapted to facilitate the connection of the two duct sections together to effectuate the user-controlled vertical disposition. 
     Broadly defined, the present invention according to another aspect includes an electronic equipment enclosure having a frame structure at least partially enclosed by a plurality of panels defining a compartment in which one or more electronic components are mounted and an extendible exhaust air duct extending upward from the top panel of the compartment. The exhaust air duct is adapted to segregate hot air being exhausted from the compartment from cool air entering the compartment, thereby improving thermal management of the enclosure. 
     In a feature of this aspect, the extendible exhaust air duct is adapted to telescope in length. 
     Broadly defined, the present invention according to another aspect includes an electronic equipment enclosure for mounting one or more electronic components. The electronic equipment enclosure includes a frame structure formed from a plurality of support posts and at least partially enclosed by a plurality of panels, the panels including at least side, top and back panels defining a compartment in which the one or more electronic components are mounted. The compartment has a top, a bottom and a rear, and the top panel includes an opening therethrough that is rectangular in shape. The electronic equipment enclosure further includes an extendible exhaust air duct extending upward from the top panel of the compartment. The exhaust air duct is rectangular in cross-section and is disposed in surrounding relation to, and in fluid communication with, the top panel opening; and the exhaust air duct is adapted to segregate hot air being exhausted from the compartment from cool air entering the compartment, thereby improving thermal management of the enclosure. 
     In a feature of this aspect, the extendible exhaust air duct is adapted to telescope in length. 
     Broadly defined, the present invention according to another aspect includes an electronic equipment enclosure having a frame structure at least partially enclosed by a plurality of panels defining a compartment in which one or more electronic components are mounted and a collapsible exhaust air duct extending upward from the top panel of the compartment. The exhaust air duct is adapted to segregate hot air being exhausted from the compartment from cool air entering the compartment, thereby improving thermal management of the enclosure. 
     In features of this aspect, the collapsible exhaust air duct is adapted to telescope in length. In another feature of this aspect, and the collapsible exhaust air duct includes four side panels that are hinged relative to each other, thereby facilitating the collapse of the exhaust air duct from a use state to a flattened state. 
     In other features of this aspect, the four side panels are connected at their corners by a hinged corner fitting; a corner lock is coupled to one of the corner fittings and adapted to maintain the side panels in the use state; each corner lock includes a main body, a lock plate, and a lock screw; each corner fitting extends substantially along the length of each of an edge of a respective panel and an edge of a respective adjacent panel; an upper edge of each side panel is flared outward; and a respective seal is attached to the upper edge of each side panel to limit air escaping from between an upper end of the duct section and a ceiling structure. 
     Broadly defined, the present invention according to another aspect includes an electronic equipment enclosure for mounting one or more electronic components. The electronic equipment enclosure includes a frame structure formed from a plurality of support posts and at least partially enclosed by a plurality of panels, the panels including at least side, top and back panels defining a compartment in which the one or more electronic components are mounted. The compartment has a top, a bottom and a rear, and the top panel includes an opening therethrough that is rectangular in shape. The electronic equipment enclosure further includes a collapsible exhaust air duct extending upward from the top panel of the compartment. The exhaust air duct is rectangular in cross-section and is disposed in surrounding relation to, and in fluid communication with, the top panel opening; and the exhaust air duct is adapted to segregate hot air being exhausted from the compartment from cool air entering the compartment, thereby improving thermal management of the enclosure. 
     In features of this aspect, the collapsible exhaust air duct is adapted to telescope in length, and the collapsible exhaust air duct includes four side panels that are hinged relative to each other, thereby facilitating the collapse of the exhaust air duct from a use state to a flattened state. 
     In other features of this aspect, the four air duct panels are connected at their corners by a hinged corner fitting; a corner lock is coupled to one of the corner fittings and adapted to maintain the air duct panels in the use state; each corner lock includes a main body, a lock plate, and a lock screw; each corner fitting extends substantially along the length of each of an edge of a respective panel and an edge of a respective adjacent panel; an upper edge of each air duct panel is flared outward; and a respective seal is attached to the upper edge of each air duct panel to limit air escaping from between an upper end of the duct section and a ceiling structure. 
     Broadly defined, the present invention according to another aspect includes an electronic equipment enclosure, including a frame structure at least partially enclosed by a plurality of panels defining a compartment in which one or more electronic components are mounted and an exhaust air duct with a lower duct section extending upward from the top panel of the compartment and an upper duct section extending upward from an upper end of the lower duct section. The exhaust air duct is adapted to segregate hot air being exhausted from the compartment from cool air entering the compartment, thereby improving thermal management of the enclosure. 
     In features of this aspect, the upper duct section is adapted to telescope from the lower duct section; each duct section includes four flat side panels connected at their corners by a corner fitting; each corner fitting is hinged; each corner fitting in the lower duct section is slidably coupled to a respective corner fitting in the upper duct section; a corner lock is coupled to one of the corner fittings and adapted to maintain the position of the upper duct section relative to the lower duct section; each corner lock includes a main body, a lock plate, and a lock screw; each corner fitting includes a pair of clamp fingers on the outer side thereof for engaging the respective corner lock; each corner fitting includes a pair of fingers defining a panel channel in which an edge of a side panel is inserted and retained; each side panel includes a plurality of raised structures along its lateral edges, and the structures are engaged within the panel channel; each raised structure is a boss; and each corner fitting extends substantially along the length of each of an edge of a respective panel and an edge of a respective adjacent panel. 
     In other features of this aspect, the upper duct section telescopes from within the lower duct section; a respective seal is attached to an upper edge of each panel of the lower duct section to limit air escaping from between the upper end of the lower duct section and a lower end of the upper duct section; each side panel includes a plurality of raised structures along its upper edge, and the structures are engaged within a channel of the seal; and each raised structure is an outwardly-extending tab. 
     In still other features of this aspect, the upper duct section telescopes from around the periphery of the lower duct section, and a respective seal is attached to a lower edge of each panel of the upper duct section to limit air escaping from between the upper end of the lower duct section and a lower end of the upper duct section. 
     In still yet another feature of this aspect, at least one panel in a first of the two duct sections includes a column of openings, and a respective corresponding panel in a second of the two duct sections includes a corresponding mounting feature such that when the first duct section and the second duct section are telescopically assembled to each other, the mounting feature of the second duct section may be aligned with any opening of the column of openings, thereby facilitating the attachment of the second duct section to the first duct section at a desired height. 
     Broadly defined, the present invention according to another aspect includes an electronic equipment enclosure for mounting one or more electronic components, including a frame structure formed from a plurality of support posts and at least partially enclosed by a plurality of panels. The panels include at least side, top and back panels defining a compartment in which the one or more electronic components are mounted. The compartment has a top, a bottom and a rear, and the top panel includes an opening therethrough that is rectangular in shape. The electronic equipment enclosure further includes an exhaust air duct with a lower duct section extending upward from the top panel of the compartment, and an upper duct section extending upward from an upper end of the lower duct section. Each duct section is rectangular in cross-section, and a lower end of the lower duct section is disposed in surrounding relation to, and in fluid communication with, the top panel opening. The exhaust air duct is adapted to segregate hot air being exhausted from the compartment from cool air entering the compartment, thereby improving thermal management of the enclosure. 
     In features of this aspect, the upper duct section is adapted to telescope from the lower duct section; each duct section includes four flat side panels connected at their corners by a corner fitting; each corner fitting is hinged; each corner fitting in the lower duct section is slidably coupled to a respective corner fitting in the upper duct section; a corner lock is coupled to one of the corner fittings and adapted to maintain the position of the upper duct section relative to the lower duct section; each corner lock includes a main body, a lock plate, and a lock screw; and each corner fitting includes a pair of clamp fingers on the outer side thereof for engaging the respective corner lock. 
     In other features of this aspect, each corner fitting includes a pair of fingers defining a panel channel in which an edge of an air duct panel is inserted and retained; each air duct panel includes a plurality of raised structures along its lateral edges, and the structures are engaged within the panel channel; and each raised structure is a boss. 
     In another feature of this aspect, each corner fitting extends substantially along the length of each of an edge of a respective panel and an edge of a respective adjacent panel. 
     In still other features of this aspect, the upper duct section telescopes from within the lower duct section; a respective seal is attached to an upper edge of each panel of the lower duct section to limit air escaping from between the upper end of the lower duct section and a lower end of the upper duct section; each air duct panel includes a plurality of raised structures along its upper edge, and the structures are engaged within a channel of the seal; each raised structure is an outwardly-extending tab; the upper duct section telescopes from around the periphery of the lower duct section; and a respective seal is attached to a lower edge of each panel of the upper duct section to limit air escaping from between the upper end of the lower duct section and a lower end of the upper duct section. 
     In still yet another feature of this aspect, at least one panel in a first of the two duct sections includes a column of openings. A respective corresponding panel in a second of the two duct sections includes a corresponding mounting feature such that when the first duct section and the second duct section are telescopically assembled to each other, the mounting feature of the second duct section may be aligned with any opening of the column of openings, thereby facilitating the attachment of the second duct section to the first duct section at a desired height. 
     Broadly defined, the present invention according to another aspect includes an electronic equipment enclosure, including a frame structure at least partially enclosed by a plurality of panels defining a compartment in which one or more electronic components are mounted, and an exhaust air duct, having four side panels connected by four corner fittings, extending upward from the top panel of the compartment. The exhaust air duct is adapted to segregate hot air being exhausted from the compartment from cool air entering the compartment, thereby improving thermal management of the enclosure. 
     In features of this aspect, each corner fitting extends substantially along the length of each of an edge of a respective panel and an edge of a respective adjacent panel; the exhaust air duct is adapted to telescope in length; the corner fittings include hinges, thereby facilitating the collapse of the exhaust air duct from a use state to a flattened state; each hinge is a living hinge; each corner fitting is formed in an extrusion process; each corner fitting has a uniform cross-section; and each panel of the exhaust air duct is planar in form. 
     In other features of this aspect, a corner lock is coupled to one of the corner fittings and adapted to maintain the side panels in the use state; each corner lock includes a main body, a lock plate, and a lock screw; an upper edge of each side panel is flared outward; and a respective seal is attached to the upper edge of each side panel to limit air escaping from between an upper end of the duct section and a ceiling structure. 
     In other features of this aspect, each corner fitting includes two finger arrays connected together by the hinge; each finger array includes a pair of fingers defining a channel; and each pair of fingers includes a latch finger with a hook adapted to fit over a raised structure on a side panel. 
     In still other features of this aspect, each corner fitting is formed in a co-extrusion process using a first material for the hinge and a second material for the remainder of the corner fitting, and each corner fitting has a uniform cross-section. 
     In still yet other features of this aspect, each corner fitting includes a pair of fingers defining a panel channel in which an edge of a side panel is inserted and retained; and each side panel includes a plurality of raised structures along its lateral edges, and the structures are engaged within the panel channel. 
     Broadly defined, the present invention according to another aspect includes an electronic equipment enclosure for mounting one or more electronic components, including a frame structure formed from a plurality of support posts and at least partially enclosed by a plurality of panels. The panels include at least side, top and back panels defining a compartment in which the one or more electronic components are mounted. The compartment has a top, a bottom and a rear, and the top panel includes an opening therethrough that is rectangular in shape. The electronic equipment enclosure further includes an exhaust air duct, having four side panels connected by four corner fittings, extending upward from the top panel of the compartment. The exhaust air duct is rectangular in cross-section and is disposed in surrounding relation to, and in fluid communication with, the top panel opening, and the exhaust air duct is adapted to segregate hot air being exhausted from the compartment from cool air entering the compartment, thereby improving thermal management of the enclosure. 
     In features of this aspect, each corner fitting extends substantially along the length of each of an edge of a respective panel and an edge of a respective adjacent panel; the exhaust air duct is adapted to telescope in length; each corner fitting is formed in an extrusion process; each corner fitting has a uniform cross-section; and each panel of the exhaust air duct is planar in form. 
     In other features of this aspect, the corner fittings include hinges, thereby facilitating the collapse of the exhaust air duct from a use state to a flattened state; a corner lock is coupled to one of the corner fittings and adapted to maintain the air duct panels in the use state; each corner lock includes a main body, a lock plate, and a lock screw; an upper edge of each air duct panel is flared outward; a respective seal is attached to the upper edge of each air duct panel to limit air escaping from between an upper end of the duct section and a ceiling structure; each hinge is a living hinge; each corner fitting includes two finger arrays connected together by the hinge; each finger array includes a pair of fingers defining a channel; each pair of fingers includes a latch finger with a hook adapted to fit over a raised structure on an air duct panel; each corner fitting is formed in a co-extrusion process using a first material for the hinge and a second material for the remainder of the corner fitting; and each corner fitting has a uniform cross-section. 
     In still other features of this aspect, each corner fitting includes a pair of fingers defining a panel channel in which an edge of an air duct panel is inserted and retained; and each air duct panel includes a plurality of raised structures along its lateral edges, and the structures are engaged within the panel channel. 
     Broadly defined, the present invention according to another aspect includes an extendible exhaust air duct, for an electronic equipment enclosure having a frame structure at least partially enclosed by a plurality of panels defining a compartment in which one or more electronic components are mounted, that is adapted to extend upward from the top panel of the compartment, and that is adapted to segregate hot air being exhausted from the compartment from cool air entering the compartment, thereby improving thermal management of the enclosure. 
     In a feature of this aspect, the extendible exhaust air duct is adapted to telescope in length. 
     Broadly defined, the present invention according to another aspect includes an extendible exhaust air duct for an electronic equipment enclosure that includes a frame structure formed from a plurality of support posts and at least partially enclosed by a plurality of panels. The panels include at least side, top and back panels defining a compartment in which the one or more electronic components are mounted. The compartment has a top, a bottom and a rear, and the top panel includes an opening therethrough that is rectangular in shape. The extendible exhaust air duct is adapted to extend upward from the top panel of the compartment; the exhaust air duct is rectangular in cross-section and is disposed in surrounding relation to, and in fluid communication with, the top panel opening; and the exhaust air duct is adapted to segregate hot air being exhausted from the compartment from cool air entering the compartment, thereby improving thermal management of the enclosure. 
     In a feature of this aspect, the extendible exhaust air duct is adapted to telescope in length. 
     Broadly defined, the present invention according to another aspect includes a collapsible exhaust duct, for an electronic equipment enclosure having a frame structure at least partially enclosed by a plurality of panels defining a compartment in which one or more electronic components are mounted, that is adapted to extend upward from the top panel of the compartment, and that is adapted to segregate hot air being exhausted from the compartment from cool air entering the compartment, thereby improving thermal management of the enclosure. 
     In a feature of this aspect, the collapsible exhaust duct is adapted to telescope in length. 
     In other features of this aspect, the collapsible exhaust duct includes four side panels that are hinged relative to each other, thereby facilitating the collapse of the exhaust duct from a use state to a flattened state; the four side panels are connected at their corners by a hinged corner fitting; a corner lock is coupled to one of the corner fittings and adapted to maintain the exhaust duct panels in the use state; each corner lock includes a main body, a lock plate, and a lock screw; each corner fitting extends substantially along the length of each of an edge of a respective panel and an edge of a respective adjacent panel; an upper edge of each exhaust duct panel is flared outward; and a respective seal is attached to the upper edge of each exhaust duct panel to limit air escaping from between an upper end of the duct section and a ceiling structure. 
     Broadly defined, the present invention according to another aspect includes a collapsible exhaust duct for an electronic equipment enclosure having a frame structure formed from a plurality of support posts and at least partially enclosed by a plurality of panels. The panels include at least side, top and back panels defining a compartment in which the one or more electronic components are mounted. The compartment has a top, a bottom and a rear, and the top panel includes an opening therethrough that is rectangular in shape. The collapsible exhaust duct is adapted to extend upward from the top panel of the compartment; the exhaust duct is rectangular in cross-section and is disposed in surrounding relation to, and in fluid communication with, the top panel opening; and the exhaust duct is adapted to segregate hot air being exhausted from the compartment from cool air entering the compartment, thereby improving thermal management of the enclosure. 
     In a feature of this aspect, the collapsible exhaust duct is adapted to telescope in length. 
     In other features of this aspect, the collapsible exhaust duct includes four side panels that are hinged relative to each other, thereby facilitating the collapse of the exhaust duct from a use state to a flattened state; the four exhaust duct panels are connected at their corners by a hinged corner fitting; a corner lock is coupled to one of the corner fittings and adapted to maintain the exhaust duct panels in the use state; each corner lock includes a main body, a lock plate, and a lock screw; each corner fitting extends substantially along the length of each of an edge of a respective panel and an edge of a respective adjacent panel; an upper edge of each exhaust duct panel is flared outward; and a respective seal is attached to the upper edge of each exhaust duct panel to limit air escaping from between an upper end of the duct section and a ceiling structure. 
     Broadly defined, the present invention according to another aspect includes an exhaust duct for an electronic equipment enclosure having a frame structure at least partially enclosed by a plurality of panels defining a compartment in which one or more electronic components are mounted. The exhaust duct includes a lower duct section extending upward from the top panel of the compartment and an upper duct section extending upward from an upper end of the lower duct section. The exhaust duct is adapted to segregate hot air being exhausted from the compartment from cool air entering the compartment, thereby improving thermal management of the enclosure. 
     In a feature of this aspect, the upper duct section is adapted to telescope from the lower duct section. 
     In other features of this aspect, each duct section includes four flat side panels connected at their corners by a corner fitting; each corner fitting is hinged; each corner fitting in the lower duct section is slidably coupled to a respective corner fitting in the upper duct section; a corner lock is coupled to one of the corner fittings and adapted to maintain the position of the upper duct section relative to the lower duct section; each corner lock includes a main body, a lock plate, and a lock screw; each corner fitting includes a pair of clamp fingers on the outer side thereof for engaging the respective corner lock; each corner fitting includes a pair of fingers defining a panel channel in which an edge of an exhaust duct panel is inserted and retained; each panel includes a plurality of raised structures along its lateral edges, and the structures are engaged within the panel channel; each raised structure is a boss; and each corner fitting extends substantially along the length of each of an edge of a respective panel and an edge of a respective adjacent panel. 
     In other features of this aspect, the upper duct section telescopes from within the lower duct section; a respective seal is attached to an upper edge of each panel of the lower duct section to limit air escaping from between the upper end of the lower duct section and a lower end of the upper duct section; each exhaust duct panel includes a plurality of raised structures along its upper edge, and the structures are engaged within a channel of the seal; and each raised structure is an outwardly-extending tab. 
     In still other features of this aspect, the upper duct section telescopes from around the periphery of the lower duct section, and a respective seal is attached to a lower edge of each panel of the upper duct section to limit air escaping from between the upper end of the lower duct section and a lower end of the upper duct section. 
     In still yet another feature of this aspect, at least one panel in a first of the two duct sections includes a column of openings, and a respective corresponding panel in a second of the two duct sections includes a corresponding mounting feature such that when the first duct section and the second duct section are telescopically assembled to each other, the mounting feature of the second duct section may be aligned with any opening of the column of openings, thereby facilitating the attachment of the second duct section to the first duct section at a desired height. 
     Broadly defined, the present invention according to another aspect includes an exhaust duct for an electronic equipment enclosure having a frame structure formed from a plurality of support posts and at least partially enclosed by a plurality of panels. The panels include at least side, top and back panels defining a compartment in which the one or more electronic components are mounted. The compartment has a top, a bottom and a rear, and the top panel includes an opening therethrough that is rectangular in shape. The exhaust duct includes a lower duct section extending upward from the top panel of the compartment and an upper duct section extending upward from an upper end of the lower duct section. Each duct section is rectangular in cross-section; and, when disposed in surrounding relation to, and in fluid communication with, the top panel opening, the exhaust duct is adapted to segregate hot air being exhausted from the compartment from cool air entering the compartment, thereby improving thermal management of the enclosure. 
     In a feature of this aspect, the upper duct section is adapted to telescope from the lower duct section. 
     In other features of this aspect, each duct section includes four flat side panels connected at their corners by a corner fitting; each corner fitting is hinged; each corner fitting in the lower duct section is slidably coupled to a respective corner fitting in the upper duct section; a corner lock is coupled to one of the corner fittings and adapted to maintain the position of the upper duct section relative to the lower duct section; each corner lock includes a main body, a lock plate, and a lock screw; each corner fitting includes a pair of clamp fingers on the outer side thereof for engaging the respective corner lock; each corner fitting includes a pair of fingers defining a panel channel in which an edge of an exhaust duct panel is inserted and retained; each panel includes a plurality of raised structures along its lateral edges, and the structures are engaged within the panel channel; each raised structure is a boss; and each corner fitting extends substantially along the length of each of an edge of a respective exhaust duct panel and an edge of a respective adjacent exhaust duct panel. 
     In other features of this aspect, the upper duct section telescopes from within the lower duct section; a respective seal is attached to an upper edge of each panel of the lower duct section to limit air escaping from between the upper end of the lower duct section and a lower end of the upper duct section; each exhaust duct panel includes a plurality of raised structures along its upper edge, and the structures are engaged within a channel of the seal; and each raised structure is an outwardly-extending tab. 
     In still other features of this aspect, the upper duct section telescopes from around the periphery of the lower duct section, and a respective seal is attached to a lower edge of each panel of the upper duct section to limit air escaping from between the upper end of the lower duct section and a lower end of the upper duct section. 
     In still yet another feature of this aspect, at least one panel in a first of the two duct sections includes a column of openings, and a respective corresponding panel in a second of the two duct sections includes a corresponding mounting feature such that when the first duct section and the second duct section are telescopically assembled to each other, the mounting feature of the second duct section may be aligned with any opening of the column of openings, thereby facilitating the attachment of the second duct section to the first duct section at a desired height. 
     Broadly defined, the present invention according to another aspect includes an exhaust duct for an electronic equipment enclosure having a frame structure at least partially enclosed by a plurality of panels defining a compartment in which one or more electronic components are mounted. The exhaust duct includes four side panels connected by four corner fittings, adapted to extend upward from the top panel of the compartment, and the exhaust duct is adapted to segregate hot air being exhausted from the compartment from cool air entering the compartment, thereby improving thermal management of the enclosure. 
     In features of this aspect, each corner fitting extends substantially along the length of each of an edge of a respective panel and an edge of a respective adjacent panel; the exhaust duct is adapted to telescope in length; each corner fitting is formed in an extrusion process; and each corner fitting has a uniform cross-section. 
     In other features of this aspect, the corner fittings include hinges, thereby facilitating the collapse of the exhaust duct from a use state to a flattened state; a corner lock is coupled to one of the corner fittings and adapted to maintain the exhaust duct panels in the use state; each corner lock includes a main body, a lock plate, and a lock screw; an upper edge of each exhaust duct panel is flared outward; a respective seal is attached to the upper edge of each exhaust duct panel to limit air escaping from between an upper end of the duct section and a ceiling structure; each hinge is a living hinge; each corner fitting includes two finger arrays connected together by the hinge; each finger array includes a pair of fingers defining a channel; each pair of fingers includes a latch finger with a hook adapted to fit over a raised structure on an exhaust duct panel; each corner fitting is formed in a co-extrusion process using a first material for the hinge and a second material for the remainder of the corner fitting; and each corner fitting has a uniform cross-section. 
     In still other features of this aspect, each corner fitting includes a pair of fingers defining a panel channel in which an edge of an exhaust duct panel is inserted and retained, and each exhaust duct panel includes a plurality of raised structures along its lateral edges, and the structures are engaged within the panel channel. 
     Broadly defined, the present invention according to another aspect includes an exhaust duct for an electronic equipment enclosure having a frame structure formed from a plurality of support posts and at least partially enclosed by a plurality of panels. The panels include at least side, top and back panels defining a compartment in which the one or more electronic components are mounted. The compartment has a top, a bottom and a rear, and the top panel includes an opening therethrough that is rectangular in shape. The exhaust duct includes four side panels connected by four corner fittings, and is adapted to extend upward from the top panel of the compartment. Furthermore, the exhaust duct is rectangular in cross-section; and, when disposed in surrounding relation to, and in fluid communication with, the top panel opening, the exhaust duct is adapted to segregate hot air being exhausted from the compartment from cool air entering the compartment, thereby improving thermal management of the enclosure. 
     In features of this aspect, each corner fitting extends substantially along the length of each of an edge of a respective panel and an edge of a respective adjacent panel; the exhaust duct is adapted to telescope in length; each corner fitting is formed in an extrusion process; and each corner fitting has a uniform cross-section. 
     In other features of this aspect, the corner fittings include hinges, thereby facilitating the collapse of the exhaust duct from a use state to a flattened state; a corner lock is coupled to one of the corner fittings and adapted to maintain the exhaust duct panels in the use state; each corner lock includes a main body, a lock plate, and a lock screw; an upper edge of each exhaust duct panel is flared outward; a respective seal is attached to the upper edge of each exhaust duct panel to limit air escaping from between an upper end of the duct section and a ceiling structure; each hinge is a living hinge; each corner fitting includes two finger arrays connected together by the hinge; each finger array includes a pair of fingers defining a channel; each pair of fingers includes a latch finger with a hook adapted to fit over a raised structure on an exhaust duct panel; each corner fitting is formed in a co-extrusion process using a first material for the hinge and a second material for the remainder of the corner fitting; and each corner fitting has a uniform cross-section. 
     In still other features of this aspect, each corner fitting includes a pair of fingers defining a panel channel in which an edge of an exhaust duct panel is inserted and retained, and each exhaust duct panel includes a plurality of raised structures along its lateral edges, and the structures are engaged within the panel channel. 
     Broadly defined, the present invention according to another aspect includes a method of installing an exhaust duct on an electronic equipment enclosure having a frame structure formed from a plurality of support posts and at least partially enclosed by a plurality of panels. The panels include at least side, top and back panels defining a compartment in which the one or more electronic components are mounted. The compartment has a top, a bottom and a rear, and the top panel includes an opening therethrough that is rectangular in shape. The method includes the steps of providing an exhaust duct, having four side panels connected to one another by hinges, in a collapsed state; opening the exhaust duct by rotating the panels relative to each other, about the hinges, to place the exhaust duct in a use state; and attaching a lower end of the exhaust duct to the equipment enclosure such that an interior of the exhaust duct is in fluid communication with an interior of the compartment via the opening in the top panel of the enclosure. 
     In a feature of this aspect, in the use state, the exhaust duct has a rectangular cross-section. 
     In other features of this aspect, the providing step includes shipping the exhaust duct to an installation site, and the providing step includes, prior to shipping the exhaust duct to an installation site, connecting a corner fitting, incorporating at least one of the hinges, to a lateral edge of a first panel and a lateral edge of a second panel. 
     Broadly defined, the present invention according to still another aspect includes an electronic equipment enclosure for mounting one or more electronic components having a frame structure formed from a plurality of support posts and at least partially enclosed by a plurality of panels. The panels include at least side, top and back panels defining a compartment in which the one or more electronic components are mounted. The compartment has a top, a bottom and a rear, and the top panel includes an opening therethrough that is rectangular in shape. The electronic equipment enclosure includes an exhaust air duct having at least one duct section having four side panels, each side panel having an outwardly flared portion at an upper edge thereof, extending upward from the top panel of the compartment. The exhaust air duct is rectangular in cross-section and is disposed in surrounding relation to, and in fluid communication with, the top panel opening. The exhaust air duct is adapted to segregate hot air being exhausted from the compartment from cool air entering the compartment, thereby improving thermal management of the enclosure. 
     In features of this aspect, each outwardly flared portion includes an outwardly angled portion of a respective upper portion of a side panel; the electronic equipment enclosure further comprises a top seal mounted on each respective upper edge; and each air duct side panel is generally planar in form, and each outwardly flared portion includes an outwardly flared top seal mounted on an upper edge of a respective air duct side panel. 
     Broadly defined, the present invention according to still yet another aspect includes an exhaust duct for an electronic equipment enclosure having a frame structure formed from a plurality of support posts and at least partially enclosed by a plurality of panels. The panels include at least side, top and back panels defining a compartment in which the one or more electronic components are mounted. The compartment has a top, a bottom and a rear, and the top panel includes an opening therethrough that is rectangular in shape. The exhaust duct includes at least one duct section having four side panels, each side having an outwardly flared portion at an upper edge thereof. The exhaust duct is adapted to extend upward from the top panel of the compartment; the exhaust duct is rectangular in cross-section; and when disposed in surrounding relation to, and in fluid communication with, the top panel opening, the exhaust duct is adapted to segregate hot air being exhausted from the compartment from cool air entering the compartment, thereby improving thermal management of the enclosure. 
     In features of this aspect, each outwardly flared portion includes an outwardly angled portion of a respective upper portion of a side panel; the exhaust duct further comprises a top seal mounted on each respective upper edge; and each air duct side panel is generally planar in form, and each outwardly flared portion includes an outwardly flared top seal mounted on an upper edge of a respective air duct side panel. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further features, embodiments, and advantages of the present invention will become apparent from the following detailed description with reference to the drawings, wherein: 
         FIG. 1  is a rear isometric view of a ducted exhaust equipment enclosure in accordance with a preferred embodiment of the present invention; 
         FIG. 2  is a left plan view of the ducted exhaust equipment enclosure of  FIG. 1 ; 
         FIG. 3  is a rear plan view of the ducted exhaust equipment enclosure of  FIG. 1 ; 
         FIG. 4  is a front plan view of the ducted exhaust equipment enclosure of  FIG. 1 ; 
         FIG. 5  is a top plan view of the ducted exhaust equipment enclosure of  FIG. 1 ; 
         FIG. 6  is a bottom plan view of the ducted exhaust equipment enclosure of  FIG. 1 ; 
         FIG. 7  is a left side cross-sectional view of the ducted exhaust equipment enclosure of  FIG. 1 , taken along the line  7 - 7 ; 
         FIG. 8  is an isometric view of the exhaust air duct of  FIG. 1 ; 
         FIG. 9  is an isometric view of an exemplary telescoping exhaust air duct, for use with the ducted exhaust equipment enclosure of  FIG. 1 , in accordance with one or more preferred embodiments of the present invention; 
         FIG. 10  is an isometric view of another exemplary telescoping exhaust air duct, for use with the ducted exhaust equipment enclosure of  FIG. 1 , in accordance with one or more preferred embodiments of the present invention; 
         FIG. 11  is an isometric view of the telescoping exhaust air duct shown installed on the ducted exhaust equipment enclosure of  FIG. 1 ; 
         FIG. 12  is a partially exploded isometric view of some of the elements of the upper duct section of the telescoping exhaust air duct of  FIG. 10 ; 
         FIG. 13  is a partially exploded isometric view of some of the elements of the lower duct section of the telescoping exhaust air duct of  FIG. 10 ; 
         FIG. 14  is an enlarged, partially exploded isometric view of portions of the elements of  FIG. 13 ; 
         FIG. 15  is a side cross-sectional view of one of the panels of the upper duct section; 
         FIG. 16  is an end plan view of one of the corner fittings of  FIG. 10 ; 
         FIG. 17  is an end cross-sectional view of one of the corner fittings of  FIG. 10 ; 
         FIG. 18  is an enlarged end view of a portion of the telescoping exhaust air duct of  FIG. 10 ; 
         FIG. 19  is an enlarged isometric view of a portion of the telescoping exhaust air duct of  FIG. 10 ; 
         FIG. 20  is an enlarged cross-sectional view of a portion of the telescoping exhaust air duct of  FIG. 10 , taken along line  20 - 20 ; 
         FIGS. 21A-21D  are a series of end views of one of the duct sections of  FIG. 10 , illustrating its collapsibility feature; 
         FIG. 22  is a schematic diagram illustrating a top view of a cylindrical exhaust duct mounted on the top panel of an enclosure; 
         FIG. 23  is a front orthogonal view of the scoop of  FIG. 7 ; 
         FIG. 24  is a rear isometric view of the ducted exhaust equipment enclosure of  FIG. 1 , shown installed on a raised floor; 
         FIG. 25  is a side cross-sectional view of the ducted exhaust equipment enclosure of  FIG. 24 , taken along the line  25 - 25 ; and 
         FIG. 26  is a schematic illustration of a series of ducted exhaust equipment enclosures. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As a preliminary matter, it will readily be understood by one having ordinary skill in the relevant art (“Ordinary Artisan”) that the present invention has broad utility and application. Furthermore, any embodiment discussed and identified as being “preferred” is considered to be part of a best mode contemplated for carrying out the present invention. Other embodiments also may be discussed for additional illustrative purposes in providing a full and enabling disclosure of the present invention. Moreover, many embodiments, such as adaptations, variations, modifications, and equivalent arrangements, will be implicitly disclosed by the embodiments described herein and fall within the scope of the present invention. 
     Accordingly, while the present invention is described herein in detail in relation to one or more embodiments, it is to be understood that this disclosure is illustrative and exemplary of the present invention, and is made merely for the purposes of providing a full and enabling disclosure of the present invention. The detailed disclosure herein of one or more embodiments is not intended, nor is to be construed, to limit the scope of patent protection afforded the present invention, which scope is to be defined by the claims and the equivalents thereof. It is not intended that the scope of patent protection afforded the present invention be defined by reading into any claim a limitation found herein that does not explicitly appear in the claim itself. 
     Thus, for example, any sequence(s) and/or temporal order of steps of various processes or methods that are described herein are illustrative and not restrictive. Accordingly, it should be understood that, although steps of various processes or methods may be shown and described as being in a sequence or temporal order, the steps of any such processes or methods are not limited to being carried out in any particular sequence or order, absent an indication otherwise. Indeed, the steps in such processes or methods generally may be carried out in various different sequences and orders while still falling within the scope of the present invention. Accordingly, it is intended that the scope of patent protection afforded the present invention is to be defined by the appended claims rather than the description set forth herein. 
     Additionally, it is important to note that each term used herein refers to that which the Ordinary Artisan would understand such term to mean based on the contextual use of such term herein. To the extent that the meaning of a term used herein—as understood by the Ordinary Artisan based on the contextual use of such term—differs in any way from any particular dictionary definition of such term, it is intended that the meaning of the term as understood by the Ordinary Artisan should prevail. 
     Furthermore, it is important to note that, as used herein, “a” and “an” each generally denotes “at least one,” but does not exclude a plurality unless the contextual use dictates otherwise. Thus, reference to “a picnic basket having an apple” describes “a picnic basket having at least one apple” as well as “a picnic basket having apples.” In contrast, reference to “a picnic basket having a single apple” describes “a picnic basket having only one apple.” 
     When used herein to join a list of items, “or” denotes “at least one of the items,” but does not exclude a plurality of items of the list. Thus, reference to “a picnic basket having cheese or crackers” describes “a picnic basket having cheese without crackers”, “a picnic basket having crackers without cheese”, and “a picnic basket having both cheese and crackers.” Finally, when used herein to join a list of items, “and” denotes “all of the items of the list.” Thus, reference to “a picnic basket having cheese and crackers” describes “a picnic basket having cheese, wherein the picnic basket further has crackers,” as well as describes “a picnic basket having crackers, wherein the picnic basket further has cheese.” 
     Referring now to the drawings, in which like numerals represent like components throughout the several views, the preferred embodiments of the present invention are next described. The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
       FIGS. 1-6  are various views of a ducted exhaust equipment enclosure  10  in accordance with a preferred embodiment of the present invention. More particularly,  FIG. 1  is a rear isometric view of such a ducted exhaust equipment enclosure  10 , and  FIGS. 2-6  are a left plan view, rear plan view, front plan view, top plan view and bottom plan view, respectively, of the ducted exhaust equipment enclosure of  FIG. 1 . As shown therein, the ducted exhaust equipment enclosure  10  includes a four post frame structure  12  having panels  32 , 34 , 36 , 38 , 40 , more fully described hereinbelow, partially enclosing the enclosure  10 , attached thereto and an exhaust air duct  14  extending upwardly from the top of the enclosure  10 . 
     The four post frame structure  12  may be of conventional design and construction. As shown and described, the four post frame structure  12  includes four vertical support posts  16 , upper and lower front cross members  18 , upper and lower rear cross members  20  and two pairs of upper and lower side cross members  22 . Each vertical support post  16  includes a plurality of cross member attachment apertures at each end. Two of the vertical support posts  16  are connected together at their upper and lower ends by the upper and lower front cross members  18 , respectively, and the other two support posts  16  are connected together at their upper and lower ends by the upper and lower rear cross members  20 , respectively. The front cross members  18  and their respective support posts  16  thus define a front frame  24 , and the rear cross members  20  and their respective support posts  16  define a rear frame  26 . The front and rear frames  24 , 26  may then be connected together at their respective corners by the upper and lower side cross members  22 . 
     Any known connection means may be used to join the various members together. One example of such a connection means is illustrated in  FIGS. 1-6 . Although not illustrated herein, at least one other example of conventional connection means is described in commonly-assigned U.S. Pat. No. 6,185,098, the entirety of which is incorporated herein by reference. Although likewise not illustrated herein, the precision and the stability of each of the corners of at least some types of four post frame structures may be enhanced by utilizing a self-squaring corner attachment bracket such as that disclosed by the commonly-assigned U.S. Pat. No. 5,997,117 entitled “RACK FRAME CABINET,” the entirety of which is hereby incorporated by reference. 
     It will be evident to the Ordinary Artisan that other structures may be used to form a frame structure on which panels may be mounted to form an enclosure. For example, in at least one embodiment (not illustrated), a frame structure may be formed from only two support posts. 
       FIG. 7  is a left side cross-sectional view of the ducted exhaust equipment enclosure  10  of  FIG. 1 , taken along the line  7 - 7 . As perhaps best seen in  FIG. 7 , the four post frame structure  12  further comprises three pairs of horizontal mounting rails  28 . Each horizontal mounting rail  28  includes a slot running substantially its entire length. In addition, three pairs of vertical mounting rails  30  are mounted to the horizontal mounting rails  28  using suitable fasteners held in place in the slots of the horizontal mounting rails  28 . Each vertical mounting rail  30  preferably includes a series of threaded mounting apertures, arranged in evenly-spaced sets, extending along substantially its entire length for use in mounting electronic components, peripheral devices, cable brackets, additional mounting members, or the like thereto. It is contemplated that the number of horizontal and vertical mounting rails is variable. For example, an enclosure may include two horizontal mounting rails and two vertical mounting rails. Further, although the number of horizontal mounting rails is equal to the number of vertical mounting rails in the two examples mentioned herein, it is not necessary that the number of mounting rails be equal. It is further contemplated that, alternatively, each horizontal mounting rail may include one or more rows of mounting apertures extending along its length. 
     With particular reference to  FIGS. 1 and 6 , the enclosure  10  includes a right panel  32 , a left panel  34 , a bottom panel  36 , a top panel  38  and a back panel  40 , all attached to the frame structure  12 , which partially enclose the enclosure  10 . The right and left panels  32 , 34  are similarly dimensioned and the bottom and top panels  36 , 38  are similarly dimensioned, though differently constructed. As is shown in  FIG. 4 , a front of the enclosure  10  is open, therefore, the enclosure  10  is not completely enclosed. In a contemplated variation, the enclosure  10  may include a perforated or ventilated front panel (not illustrated). The Ordinary Artisan will understand that either variation of a front panel is operative to provide a path for air to enter the enclosure  10  for cooling the components contained therein. Further, although in the illustrated arrangement the back panel  40  is, in fact, a lockable door, it will be evident to the Ordinary Artisan that alternatively other types of doors and panels may be substituted for the various panels, and that one or more of the illustrated panels (such as one or both side panels  32 , 34 ) may in some cases be omitted altogether (such as in a row of two or more adjoining enclosures  10 ). It is, however, preferred that the back panel be solid, i.e., substantially air impervious, so that heated air is prevented from escaping through the door as further described hereinbelow. Any known connection means may be used to join the panels to the frame structure  12 , including the back door panel  40 . 
     With reference to  FIG. 5 , the top panel  38  of the enclosure  10  includes a rectangular shaped opening  42  disposed adjacent the rear of the enclosure  10 . The opening  42  is an exhaust opening and is intended to provided an outlet for air being exhausted from the enclosure  10 , as further described hereinbelow. 
     As perhaps best seen in  FIG. 1 , the opening  42  of the top panel  38  is surrounded by, and in fluid communication with, the exhaust air duct  14 .  FIG. 8  is an isometric view of the exhaust air duct  14  of  FIG. 1 . The exhaust air duct  14  is generally rectangular in cross-section and has four generally planar panels  54 , 56  of substantially similar length forming a body thereof. The width of the front and rear panels  54  is selected to correspond to the width of the enclosure  10 , with the width being as wide as possible and still be mountable to the top of the enclosure  10 . The width of the side panels  56  of the exhaust air duct  14  are dependent on the length or depth of the enclosure  10  and in some cases the distance between the rear of equipment mounted inside and the rear of the enclosure  10 . The panels  54 , 56  are preferably constructed of a smooth, stiff material providing a low-restriction exhaust air duct  14  that is self-supporting. Examples include, but are not limited to, aluminum or steel of a sufficient gauge to permit self-support. Significantly, unlike corrugated air ducts, the smooth nature of the material provides a surface that encourages, rather than hinders air flow. The exhaust air duct  14  is open at a bottom and top thereof to allow for unencumbered air passage there through. The rectangular cross-section and large size of the exhaust air duct  14  provides for a considerably larger cross-section than that of conventional cylindrical exhaust air ducts, and thus much greater flow-through. Further, the cross-section of the exhaust air duct  14  is therefore substantially the same as that of the top panel opening  42  to allow air to flow from the top panel opening  42  through the exhaust air duct  14  without encountering any obstruction. The exhaust air duct  14  segregates the hot exhaust air from cool air entering the enclosure  10  by directing it up and away from the enclosure  10 . 
     Front and back panels  54  of the exhaust air duct  14  include flanges  58  at side edges thereof. The flanges  58  of the front and back panels  54  fold around side edges of the right and left panels  56  at the corners of the rectangular shaped exhaust air duct  14 . Any known connection means, such as screws, may be used to join the exhaust air duct panels  54 , 56  using the flanges  58  of the front and back panels  54 . This arrangement further improves the rigidity of the exhaust air duct  14 . 
     Each of the panels  54 , 56  of the exhaust air duct  14  has an additional flange  46  at a bottom edge  48  thereof for attachment to the top panel  38  of the enclosure  10  around a rim  50  of the top panel opening  42 . Furthermore, a top edge  52  of the exhaust air duct  14  may be connected to a room&#39;s return air duct, as shown schematically in  FIG. 25 . As will be evident to the Ordinary Artisan, it may be desirable to include additional features at the top edge  52  of the duct  14 , such as a mounting flange (not shown) extending around the periphery thereof, to facilitate such connection. However, the self-supporting nature of the exhaust air duct  14  enables it to be positioned upright without any support from such a return air duct. Still more preferably, the height of exhaust air duct  14  may be adjustable for use in rooms with varying ceiling heights. In order to facilitate such adjustability, the exhaust air duct  14  may have a telescoping design or some other design capable of adjustability. Such adjustability may be further enhanced by the self-supporting nature of the exhaust air duct  14 . In contrast, conventional air ducts must be attached at either end to a support because they are not self-supporting, therefore, conventional air ducts lose the freedom of adjustability that is available in the exhaust air duct  14  of the present invention. 
       FIG. 9  is an isometric view of an exemplary telescoping exhaust air duct  98 , for use with the ducted exhaust equipment enclosure  10  of  FIG. 1 , in accordance with one or more preferred embodiments of the present invention. The telescoping duct  98  comprises two duct sections  100 , 102  having a somewhat similar construction to that described above for the exhaust air duct  14 . More particularly, both duct sections  100 , 102  are open-ended and have a rectangular cross-section defined by front and back panels and left and right panels. The telescoping duct  98  includes a first duct section  100  with a rectangular cross-section that is slightly smaller in cross-section than a second duct section  102 , within which the first duct section  100  nests. The telescoping duct  98  preferably includes a means for fixing the total height of the duct  98  once it has been adjusted, i.e., once the relation of the first duct section  100  to the second duct section  102  has been decided. In the present embodiment, each of two opposing panels of the first duct section  100  includes a pair of openings (not shown), with each opening being disposed near opposite lower corners of the panels. These openings may be disposed in front and back panels or left and right panels, depending on the orientation of the telescoping duct  98  when it is installed in the enclosure  10 . Each of two opposing panels of the second duct section  102  includes a pair of columns of openings  106 , preferably evenly-spaced, that are disposed near side edges of the panels. When the telescoping duct  98  is assembled, the opposing panels of the first duct section  100  having the pair of openings described above are aligned with the opposing panels of the second duct section  102  having the columns of corresponding openings  106 . In this arrangement, the openings of the first duct section  100  may be adjusted vertically until the openings are aligned with a desired set of openings  106  of the second duct section  102 . Thus, the first duct section  100  may be moved upwardly or downwardly, thereby increasing or decreasing the height of the telescoping duct  98 , until the desired height is reached. At this point, the four openings of the first duct section  100  should be aligned with four openings  106  of the second duct section  102  that lie in the same horizontal plane. Bolts or other fasteners  208 , or some other similarly functioning connection means (such as a spring-loaded pin or the like) may be inserted through the aligned openings of the first  100  and second duct sections  102  to fix the height of the telescoping duct  98 . If it is subsequently desired to adjust the height, the bolts  208  may be removed and the first duct section  100  slid upwardly or downwardly until the new desired height is reached. 
     In the telescoping duct  98 , the second duct section  102  may include a flange  210  at bottom edges of the opposing panels that do not have the columns of openings  106 . The telescoping duct  98  may be connected to the enclosure  10  using the flanges  210 . In addition, the panels that include the columns of openings  106  may have a bottom edge that extends slightly lower than the bottom edges of the other panels. These bottom edges may extend into the opening  42  of the top panel  38  of the enclosure  10 . As will be evident to the Ordinary Artisan, the dispositions of these elements may be changed as desired. 
       FIG. 10  is an isometric view of another exemplary telescoping exhaust air duct  198 , for use with the ducted exhaust equipment enclosure  10  of  FIG. 1 , in accordance with one or more preferred embodiments of the present invention. The telescoping duct  198  comprises two duct sections  200 , 202  whose construction has some similarities to that described above for the exhaust air duct  14 . More particularly, both duct sections  200 , 202  are open-ended and have a rectangular cross-section defined by front and back panels and left and right panels. The lower duct section  202  has a rectangular cross-section that is slightly smaller in cross-section than the upper duct section  200 , within which the lower duct section  202  nests. The telescoping duct  198  preferably includes a means for fixing the total height of the duct  198  once it has been adjusted, i.e., once the relation of the upper duct section  200  to the lower duct section  202  has been decided. Thus, the upper duct section  200  may be moved upwardly or downwardly relative to the lower duct section  202 , thereby increasing or decreasing the height of the telescoping duct  198 , until the desired height is reached. That and other features of the telescoping duct  198  of  FIG. 10  are further described hereinbelow. 
       FIG. 11  is an isometric view of the telescoping exhaust air duct  198  shown installed on the ducted exhaust equipment enclosure  10  of  FIG. 1 . With reference to  FIG. 5 , the duct  198  is installed on the top of the enclosure  10  such that the rectangular shaped opening  42 , arranged in the top panel  38  of the enclosure  10  adjacent the rear thereof, is surrounded by, and in fluid communication with, the exhaust air duct  14 . The duct  198  is thus disposed adjacent the rear of the enclosure  10 , and because of the correspondence of its size and shape to that of the top or footprint of the enclosure  10 , the duct  198  thus occupies a very large proportion of the rear area of the enclosure top. It will be appreciated that the front area of the top panel  38  of the enclosure  10  may include one or more cable openings for routing cables from the interior of the enclosure  10  up through the top panel  38 . In the particular arrangement shown in  FIG. 11 , four small circular cable openings and one larger rectangular cable opening (not numbered) are shown, but other numbers and types of cable openings are likewise possible. 
       FIG. 12  is a partially exploded isometric view of some of the elements of the upper duct section  200  of the telescoping exhaust air duct  198  of  FIG. 10 , while  FIG. 13  is a partially exploded isometric view of some of the elements of the lower duct section  202  of the telescoping exhaust air duct  198  of  FIG. 10 , and  FIG. 14  is an enlarged, partially exploded isometric view of portions of the elements of  FIG. 13 . With reference to  FIG. 10 , the upper duct section  200  includes two pairs of panels  212 , 213  connected together by corner fittings  216 . Each panel  212 , 213 , which may be constructed from sheet metal, plastic laminate, plastic, or the like, or combinations thereof, preferably includes a series of raised bosses  220  along each of its lateral edges. Similarly, the lower duct section  202  includes two pairs of panels  222 , 223  connected together by corner fittings  216 , and each panel  222 , 223 , which likewise may be constructed from sheet metal, plastic laminates, plastic, or the like, or combinations thereof, preferably includes a series of raised bosses  220 , perhaps best shown in  FIG. 14 , along each of its lateral edges. Each of the panels  222 , 223  of the lower duct section preferably also includes one or more mounting apertures  218  along its base. 
       FIG. 15  is a side cross-sectional view of one of the panels  212  of the upper duct section  200 . As shown therein, the upper edge of the panel  212  includes an outwardly flared portion  246  on which a top seal or gasket  248  is mounted. In particular, the outwardly flared portion  246  is angled relative to the rest of the panel  212 , but alternatively may be more gradually flared, angled, curved or the like. Furthermore, in at least one alternative embodiment, the upper edge of the panel  212  is not flared, but the top seal (not shown) mounted thereon is flared. A bottom seal  250  is mounted along the lower edge of the panel  212 . Viewed from one end, each seal  248 , 250  includes two fingers  252 , 254  that define a channel into which fits a respective edge of the panel  212 . One finger  254  is hooked to fit over and engage a series of outwardly-extending tabs  256  along a respective upper or lower edge of the panel  212 . Referring to  FIG. 10 , the top seals  248  are angled at their ends in the form of a miter edge such that each top seal  248  fits against the top seals  248  on the sides of the upper duct section  200  that are adjacent to it. The bottom seals  250  are sized to fit close to the corner locks  238 , described below. All of the seals  248 , 250  are generally intended to close off air gaps, either between the lower duct section  202  and the upper duct section  200  or between the upper duct section  200  and the ceiling or other structure above the enclosure  10  on which the telescoping duct  198  is mounted. The top seals  248 , at least, are at least partially flexible and thus may be flexed as necessary to fit or butt against an uneven or misaligned ceiling or ceiling duct. Gaps in the upper corners, which may exist between the ends of the top seals  248  and the upper corners of the panels  212 , 213 , may be closed using a small plastic filler piece  258  (shown in  FIG. 10 ) or the like. 
       FIGS. 16 and 17  are an end plan view and an end cross-sectional view, respectively, of one of the corner fittings  216  of  FIG. 10 . In at least some embodiments, each corner fitting  216  is of identical construction. As shown in  FIGS. 16 and 17 , each corner fitting  216  includes two finger arrays  214  connected together by a hinge  224 . Each finger array  214  includes a guide finger  226 , a latch finger  228  and a clamp finger  230 . The guide finger  226  preferably includes a flexible finger tip  232  disposed at the end of a rigid portion. The guide finger  226  and latch finger  228  together define a panel channel  234  into which the lateral edge of a panel  212 , 213 , 222 , 223  may be inserted. The latch finger  228  includes a hook  236  adapted to fit over the raised bosses  220  on the edge of any of the panels  212 , 213 , 222 , 223  and thereby retain the panel edge in the channel  234 . Preferably, each corner fitting  216  is formed in a co-extrusion process using flexible polyvinyl chloride (“PVC”) for the flexible finger tips  232  and the central hinge  224  and rigid PVC for all other portions. 
       FIG. 18  is an enlarged end view of a portion of the telescoping exhaust air duct  198  of  FIG. 10 . As shown therein, each corner fitting  216  connects two panels  212 , 213  or  222 , 223  together. The lateral edge of each panel fits snugly into a respective panel channel  234  (identified in  FIGS. 16 and 17 ) defined between a guide finger  226  and the latch finger  228  adjacent thereto. The panel is retained in the channel  234  not only by the friction of the guide and latch fingers  226 , 228  but by the hook  236  at the end of the latch finger  228 , which, when the panel is seated properly within the channel  234 , fits over the line of raised bosses  220 . 
     With the corner fittings  216  in place on the edges of the panels  212 , 213 , 222 , 223 , the two duct sections  200 , 202  may be assembled by inserting the lower duct section  202  within the upper duct section  200 . In order to accomplish this, the guide fingers  226  on the corner fittings  216  of the upper duct section  200  make contact with the latch fingers  228  on the corner fittings  216  of the lower duct section, thereby causing the guide fingers  226  of the upper duct section  200 , and particularly the finger tips  232 , to be deflected slightly as shown in  FIG. 18 . This helps provide a snug fit between the respective corner fittings  216  but still permits the upper duct section  200  to be telescoped relative to the lower duct section  202  to a desired length. 
       FIG. 19  is an enlarged isometric view of a portion of the telescoping exhaust air duct  198  of  FIG. 10 . In particular,  FIG. 19  illustrates one of four corner locks  238  in its disposition at the lower end of one of the corner fittings  216  on the upper duct section  200 . The same corner lock  238  is shown in  FIG. 20 , which is an enlarged cross-sectional view of a portion of the telescoping exhaust air duct  198  of  FIG. 19 , taken along line  20 - 20 . As shown in  FIGS. 19 and 20 , the corner lock  238  includes a main body  240 , a lock plate  242 , and a lock screw  244 . The lock screw  244  is received in a threaded insert  243  carried in an opening penetrating the main body  240  such that the head of the screw  244  is accessible from the outside of the main body  240 , as shown in  FIG. 19 , and the distal end of the screw  244  is received and held in the lock plate  242 . The corner lock  238  is coupled to one of the corner fittings  216  on the lower duct section  202  by loosening the lock screw  244  and positioning the lock plate  242  within the space or channel created between the hinge  224  and the clamp fingers  230  of the lower corner fitting  216 , as shown in  FIG. 20 . With the lock plate  242  in position, the lock screw  244  may be tightened to clamp the clamp fingers  230  of the lower corner fitting  216  between the lock plate  242  and an inner surface of the main body  240  of the corner lock  238 . 
     Once all four corner locks  238  are properly coupled to the lower corner fittings  216 , the upper duct section  200  may be telescoped relative to the lower duct section  202  by loosening the lock screws  244  in all four corner locks  238 , sliding the upper corner fittings  216 , including the corner locks  238 , relative to the lower corner fittings  216 , and tightening the lock screws  244  to secure the corner locks  238  to the lower corner fittings  216  once more. In this way, the upper duct section  200  may be precisely extended any desired amount from the top of the lower duct section  202 , thereby providing infinite adjustability along the extent of the upper and lower corner fittings  216 . 
     With reference to  FIGS. 10 and 11 , one or more angle brackets  210  may be utilized to attach the lower duct section  202  to the top of the enclosure  10 . One member of each angle bracket  210  may be attached to an upper side cross member  22 , the top panel  38  or another part of the top of the enclosure  10 , while the other member of the angle bracket  210  may be attached to the bottom of the one of the panels  223  of the lower duct section  202  using the apertures  218  provided for that purpose. It is not necessary for all four sides of the lower duct section  202  to be attached to the enclosure  10 . 
     As described previously and illustrated in  FIGS. 16 and 17 , each corner fitting  216  includes a central hinge  224 .  FIGS. 21A-21D  are a series of end views of one of the duct sections  200 , 202  of  FIG. 10 , illustrating its collapsibility feature. More particularly,  FIG. 21A  is an end view of the lower duct section  202 , shown in its normal use position, while  FIG. 21B  is an end view end view of the lower duct section  202  illustrating its partial collapse,  FIG. 21C  is an end view of the lower duct section  202  illustrating its complete collapse, and  FIG. 21D  is an end view of the lower duct section  202 , shown in its completely collapsed position. The central hinges  224  of the various corner fittings  216  permit the lower duct section  202  (as well as the upper duct section  200 ), which takes the form in this respect of a parallelogram, to be collapsed completely to a relatively flat state, shown in  FIG. 21D . This feature advantageously permits each duct section  200 , 202  to be assembled at the point of manufacturing, placed in its completely collapsed state, and shipped flat to its destination, where it may be expanded to its normal use position by an installer or user. Each duct section  200 , 202  may be readied for installation by rotation or manipulation of the respective panels about the central hinges  224  to place the duct section in the use state shown in  FIG. 21A . It will be appreciated that similar construction may be utilized to provide a single (non-extendible) duct section that may likewise be collapsed for shipment or the like and opened or expanded for use. 
       FIGS. 8, 9 and 10  thus illustrate three different exhaust air ducts  14 , 98 , 198 , but only the first and third of the three are illustrated installed on top of an enclosure  10 . Nonetheless, in the descriptions that follow, it will be appreciated that in at least some embodiments, any of the latter two telescoping exhaust air ducts  98 , 198  may be substituted for the first exhaust air duct  14  without departing from the scope of the present invention. Thus, although only the first air duct  14  is further described in use hereinbelow, it will be understood that the following descriptions are equally applicable to the other air ducts  98 , 198  unless otherwise indicated. 
     Because of the positioning of the exhaust air duct  14  on the enclosure  10 , the back panel  54  thereof is nearly vertically aligned with a vertical plane of the back panel  40  of the enclosure  10 . Further, because the rectangular shape of the exhaust air duct  10  is similar to the rectangular shape of the back of the enclosure  10 , exhaust air flows freely through the exhaust air duct  14 . In contrast, in a conventional cylindrical exhaust air duct, air from the back of the angularly shaped enclosure, particularly the corners of the enclosure, must take a tortuous and winding path in order to exit the server enclosure. This relatively complex air flow scheme decreases the rate at which and the amount of air that may exit the enclosure. Further because the rectangular exhaust air duct  14  is similar in shape to the back of the enclosure  10  itself, it can be made larger in cross-section than conventional cylindrical ducts, thus allowing for more airflow through the exhaust air duct  14 . This is illustrated in  FIG. 22 , which is a schematic diagram illustrating a top view of a cylindrical exhaust duct  314  mounted on the top panel  338  of an enclosure. As shown therein, corner areas  370  of the top panel  338  block the free flow of air out of the top of the enclosure. Accordingly, the rectangular cross-section of the exhaust air duct  14  facilitates increased transfer of thermal energy from the enclosure  10  in comparison to conventional enclosures with conventional exhaust air ducts  14  because of the increased exhaust air flow rate and the decreased resistance to flow permitted by the size, shape and smooth panels of the rectangular exhaust air duct  14 . These benefits are particularly well-achieved when the width of the top opening  42  is at least 75% as wide as the width of the top panel  38 , and/or when the front-to-back depth of the top opening  42  is at least 30% as deep as the front-to-back depth of the top panel  38 , is more particularly well-achieved when the width of the top opening  42  is at least 80% as wide as the width of the top panel  38 , and/or when the front-to-back depth of the top opening  42  is at least 35% as deep as the front-to-back depth of the top panel  38 , and even more particularly well-achieved when the width of the top opening  42  is at least 85% as wide as the width of the top panel  38 , and/or when the front-to-back depth of the top opening  42  is at least 40% as deep as the front-to-back depth of the top panel  38 . 
     As shown in  FIG. 26  (described below), the exhaust air duct  14  may be connected to a room&#39;s exhaust air removal system, which commonly includes a return air duct. However, the exhaust air duct  14  does not have to be connected to a return air duct. The enclosure  10  may vent directly into the room into which the enclosure  10  is placed. This approach is more useful in rooms that have high ceilings into which to vent the hot air, however, the natural buoyancy of hot air will keep the hot vented air at or near the top of the room into which it is vented. 
     The enclosure  10  may be used in connection with a hot aisle/cold aisle configuration of a data center or computer room. If a series of enclosures  10  are arranged in a row in such configuration, the exhaust air ducts  14  form a vertical wall rising from the tops of the enclosures  10  due to their size and shape. This vertical wall may serve as a barrier to recirculation, thereby improving the performance of the hot aisle/cold aisle thermal system. 
     As seen in  FIG. 7 , the enclosure  10  may also include an air flow director or air diverter  60  located near the bottom of the enclosure  10  and generally directly beneath the opening  42  for the exhaust air duct  14 .  FIG. 23  is a front orthogonal view of the air diverter  60  of  FIG. 7 . As shown therein, the air diverter  60  comprises a planar panel  62  having a series of creases or bends therein so as to create a generally scoop-shaped structure. Preferably, the creases or bends are generally regularly spaced such that cross-section of the structure approximates an arc, as evident from  FIG. 7 . Of course, it will be evident to the Ordinary Artisan that alternatively the structure may, in fact, have a uniformly curved (non-planar) cross-section, but the use of a planar panel  62  that is bent or creased to approximate an arc cross-section may improve manufacturability. Further, it will be evident that while the present embodiment comprises a generally curved structure, it is important to note that the air diverter  60  may comprise any shape that creates a scoop effect for air flowing through the enclosure  10 . 
     The air diverter  60  has a width that at its maximum is substantially the same as the distance between the horizontal mounting rails  28 . The air diverter  60  includes a pair of wing elements  80  disposed opposite one another on opposite side edges of the air diverter  60 . The wing elements  80  extend beyond the side edges of the air diverter  60  such that they essentially span the entire distance between the horizontal mounting rails  28 . A bottom edge  64  of the air diverter  60  has a flange  66  for connecting the air diverter  60  to the bottom panel  36  of the enclosure  10 . Any known connection means may be used to join the air diverter  60  to the bottom panel  36  of the enclosure  10 . Alternatively, the air diverter  60  may be left unfastened to the bottom panel  36 , thereby permitting the air diverter  60  to be relocated forward or backward from the location illustrated in  FIG. 7 . If left unfastened, it is useful to include means for preventing the air diverter  60  from being rotated upward by the forces applied by cables as described hereinbelow. One such means is a small protuberance  81  that may be included on the wing elements and that hooks underneath the horizontal mounting rails  28  to which the diverter  60  is attached as described below. 
     The air diverter  60  further includes a “U”-shaped channel member  68  disposed at a top edge  70  thereof. The channel member  68  includes a top surface  72  and two side surfaces  74  extending from the top surface  72 . One of the side surfaces  74  is attached to the top edge  70  of the air diverter  60 . The channel member  68  is arranged such that the top surface  72  thereof extends away from a front surface  76  of the air diverter  60 . The channel member  68  provides rigidity for the air diverter  60 . 
     The channel member  68  also serves another purpose, as next described. As can be seen in  FIG. 7 , the enclosure  10  includes a cable openings  96  located behind and beneath the air diverter  60  and in the top panel  38 . Cables (not shown) used to power components or supply data to or from components stored in the enclosure  10  can be routed through the cable openings  96 . In particular, it is contemplated that a substantial number of cables may be disposed between the back panel  40  of the enclosure  10  and the air diverter  60 , and in fact, the back of the air diverter  60  may aid in forcing the cables toward the rear of the enclosure  10 . Such cables may exert a considerable amount of tension on the back of the air diverter and particularly on the uppermost and/or rearmost surfaces of the channel member  68 . If these surfaces are rough, they could potentially cause considerable chafing on the surfaces of the cables, thereby damaging them. Advantageously, because the distal edge of the channel member  68  is pointed downward, the cables instead make contact with the relatively smooth surfaces of the top and side surfaces  72 , 74 , thereby protecting the cables from damage. In this regard, in at least one alternative embodiment (not illustrated), the channel member  68  may be replaced by an arcuate member that provides a minimum radius of curvature, thereby preventing cables from being bent unnecessarily. 
     The air diverter  60  further includes a pair of connection tabs  78  disposed on the wing elements  80  thereof. The wing elements  80  are generally positioned at a height corresponding to the elevation of the lowermost horizontal mounting rail  28  within the enclosure  10 , and the tabs  78  therefore provide a means for the air diverter  60  to be connected to a pair of horizontal mounting rails  28  of the enclosure  10  using the mounting rail slots, described previously and visible in  FIG. 7 . Further, any known connection means may be used to connect the air diverter  60  to the bottom panel  36  of the enclosure  10  as desired. 
     Notably, although not shown, because the wing elements  80  extend out from the side edges of the air diverter  60 , the vertical mounting rails  30  may alternatively be disposed between the side edges of the air diverter  60  and the horizontal mounting rails  28  in the inset areas  83 , 85  located above and below the wing elements  80 . Thus, the vertical mounting rails may be arranged by a user at nearly any location along the horizontal mounting rails  28  from the front to the back of the enclosure  10 , other than where the wing elements  80  are present. The lower inset area  85  also provides another function, in that cables entering the bottom of the enclosure  10  may be routed forward almost immediately after entering the enclosure using the space provided by the lower inset area  85 . In the absence of such a space, cables would have to be routed up and over the wing elements, thus making the cables unnecessarily long. 
     In use, the ducted exhaust equipment enclosure  10  is typically, though not always, installed on a raised floor  82 .  FIG. 24  is a rear isometric view of the ducted exhaust equipment enclosure  10  of  FIG. 1 , shown installed on a raised floor  82 , and  FIG. 25  is a side cross-sectional view of the ducted exhaust equipment enclosure  10  of  FIG. 24 , taken along the line  25 - 25 . The raised floor  82  includes a plurality of floor panels or tiles  84  of standard size and conventional design, all supported above the permanent floor at a desired height. The floor tiles  84  conventionally include solid tiles as well as perforated or ventilated tiles, the latter of which are designed to permit cool air supplied from the space beneath the floor  82 , commonly referred to as the raised floor plenum, to flow therethrough. In particular, a ventilated tile may be located directly in front of the enclosure  10  to provide the most direct path to the interior of the enclosure and the air intakes for the equipment  86  located inside. Further, although not specifically illustrated herein, the area directly underneath such an enclosure  10  is often left fully or partially open by eliminating one or more tiles  84 , by using tiles  84  with large openings therein, or by using tiles  84  that are less than full-size. 
       FIG. 26  is a schematic illustration of a series of ducted exhaust equipment enclosures  10  showing cool air flowing in and hot return air flowing out. As shown in  FIGS. 24 and 25 , once one or more enclosures  10  are installed on the raised floor  82 , electronic equipment  86  is installed in the various equipment enclosures  10 , typically by attaching the equipment  86  to the vertical mounting rails  30 , and operated normally. As described previously, the equipment  86  generates considerable thermal energy while it operates. The thermal energy is carried by air currents which may be forced or forcibly drawn out of the rear of the various active pieces of equipment  86  by internal fans (not shown), often supplemented by separate fans (not shown) mounted in or on the enclosures  10 . The air-impervious rear door  40  prevents heated air from escaping out the rear of the enclosure  10  where it would mix with cool air outside and be drawn back through the enclosures  10 . Heated air near the bottom of each enclosure  10  is further redirected upward by the air diverters  60 . The heated air is then exhausted through the exhaust air ducts  14  as represented by arrows  90 , and into the return air duct  92 . Once there, the heated air is handled by the CRAC, sometimes in combination with additional ducts, fans, partitions, and/or other equipment (not shown). 
     At the same time, cool air, represented by arrows  94 , flows up through the perforated tiles  84  and in through the front of the enclosure  10 , thereby facilitating the flow of air through the enclosure  10  and cooling the equipment  86  mounted therein. Although not shown, cool air is often also guided through the openings directly beneath the enclosure  10 . Care must be taken to force such air to the front of the equipment  86  to avoid letting it escape immediately up the back of the enclosure  10 . 
     Thus, the ducted exhaust equipment enclosure  10  allows the components  86  stored therein to draw the required volume of air through the enclosure  10 , and then directs the exhaust out of and away from the enclosure  10  thereby eliminating the problem of air recirculation. The ducted exhaust equipment enclosure  10  segregates hot exhaust air by directing it up an exhaust air duct  14  at the top rear of the enclosure  10 . This approach delivers enhanced cooling of components resulting in a more efficient use of available cool air and better overall heat transfer away from components. 
     Preferably, and as shown in  FIG. 26 , the exhaust air duct  14  is connected to a drop ceiling return air plenum. However, this is not necessary where high ceilings can offer sufficient clearance for the return air to stratify above the cold air in the room. 
     Several benefits become obvious with this architecture. For example, enclosures  10  do not have to be oriented front-to-front and back-to-back along hot aisle/cold aisle rows, as they do with conventional hot aisle/cold aisle arrangements. This freedom allows enclosure arrangements to be driven by other infrastructure requirements. In addition, up to 100% of the exposed floor can be perforated. Perforated tiles  84  can be located anywhere in the room. Using ducted exhaust equipment enclosures  10  allows the entire data center to be cold, i.e., no more hot zones. Cold intake air can be pulled from anywhere in the room. An enclosure  10  no longer has to obtain all of the airflow needed from the raised floor tile directly in front or adjacent to it. As such, airflow balancing issues are significantly reduced, if not, alleviated. By enabling cold air to be delivered through 100% of the tile in the raised floor  82 , it is contemplated that the airflow available to any given enclosure  10  can be doubled thereby doubling the heat load capacity of the enclosure  10 . 
     It is important to note that because the ducted exhaust equipment enclosures can be used in data centers both with raised floors  82  or without raised floors  82 , they are extremely versatile. The ducted exhaust equipment enclosures  10  can be used in rooms with or without a raised floor  82  and can be partially or completely cooled using a raised floor plenum or by an alternative cooling means such as ducts within a data center. Accordingly, the following scenarios are possible with the ducted exhaust equipment enclosures: 1) a data center wherein cold air is supplied using only a raised floor approach, 2) a data center wherein no raised floor is present and cold air is supplied using only alternative approaches to a raised floor, e.g., ducts in the room, 3) a data center wherein a raised floor  82  is present but cold air is supplied by ducts in the room, and 4) a data center wherein cold air is partially supplied by ducts in the room and partially supplied by a raised floor plenum. 
     Use of the ducted exhaust equipment enclosures  10  also creates the opportunity to deploy high density applications in a non-raised floor environment because cold air can be delivered directly into the room rather than through a raised floor. In addition, the use of ducted exhaust equipment enclosures  10  avoids any dependency on booster fans, with the accompanying concerns over additional heat loads, fan failure and redundancy, thereby reducing the cost of equipping a data center. 
     In the process described above, each air diverter  60  reduces or eliminates eddies that would otherwise be present in the hot return air at the bottom rear of the enclosure  10 . Such eddies can cause computer components mounted at the bottom of the enclosure  10  to operate at a higher temperature than components mounted higher up in the enclosure  10 . The air diverter  60  reduces or eliminates such eddies by turning hot return air upward in the direction of primary flow of hot return air. It is contemplated that intermediate half-scoop air diverters (not shown) may also be added at various vertical spacing locations along the back of the enclosure  10 . These intermediate half-scoops of various sizes and shapes may be used to further improve air flow and air balance. Advantageously, although the exhaust air duct  14  may be used by itself, the various scoops help start the vertical flow of heated air up toward the duct  14 , thereby making it function more efficiently than if used by itself. 
     The enclosure  10  may include additional features to aid in airflow management of the enclosure  10 . One such feature is the inclusion of metal bracket seals  88  around the connection means used to connect the back door panel  40  to the enclosure  10 . The seals  88  further ensure that exhaust air exits the enclosure  10  via the exhaust air duct  14  rather than through small openings around the connection means or edges of the door. Further, foam or rubber gaskets (not shown) may be added to, or may replace, the metal bracket seals  88  to create a further barrier to air release. 
     Another contemplated feature is a brush opening in the bottom panel  36  of the enclosure  10 . Often an enclosure will have an opening in the bottom panel thereof for receipt of cables that provide power and other input or output to the components stored in the enclosure. Unfortunately, air is able to flow freely through the opening thereby altering the intended airflow scheme of the enclosure. It is possible to include a plurality of bristles extending inwardly from opposing sides of the opening such that exterior ends of the bristles are touching. The bristles essentially cover the opening thereby preventing air from flowing there through. In the same instance, the cables are still able to pass through the opening by displacing the bristles for their passage there through. Although the brushes are not shown in  FIG. 7 , it is contemplated that the cable opening  96  of the enclosure  10  will be a brush opening. 
     Based on the foregoing information, it is readily understood by those persons skilled in the art that the present invention is susceptible of broad utility and application. Many embodiments and adaptations of the present invention other than those specifically described herein, as well as many variations, modifications, and equivalent arrangements, will be apparent from or reasonably suggested by the present invention and the foregoing descriptions thereof, without departing from the substance or scope of the present invention. 
     Accordingly, while the present invention has been described herein in detail in relation to its preferred embodiment, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for the purpose of providing a full and enabling disclosure of the invention. The foregoing disclosure is not intended to be construed to limit the present invention or otherwise exclude any such other embodiments, adaptations, variations, modifications or equivalent arrangements; the present invention being limited only by the claims appended hereto and the equivalents thereof. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for the purpose of limitation.