Patent Publication Number: US-2023161128-A1

Title: Heat management systems for enclosures for power and optical fiber networks

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is a continuation of U.S. patent application Ser. No. 17/328,443 filed May 21, 2021, which application claims priority to U.S. Provisional Patent Application Ser. No. 63/031,627, filed May 29, 2020, the entire contents of each are incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates to communication systems and, in particular, to enclosures for optical fiber. 
     BACKGROUND 
     In many information and communication technology systems, network-connected electronic devices are deployed in locations where a local electric power source is not available. With the proliferation of the Internet of Things (“IoT”), autonomous driving, fifth generation (“5G”) cellular service, and the like, it is anticipated that network-connected electronic devices will increasingly be deployed at locations that lack a conventional electric power source. 
     Electric power may be provided to such remote network-connected electronic devices in numerous ways. One technology for delivering power to such remote network-connected electronic devices is power-plus-fiber cables. Power-plus-fiber cables are a type of composite power-data cable that includes both power conductors and optical fibers within a common cable jacket. Data/power grids are being deployed that have enclosures for power and fiber optic cables. Such data/power grids may route both power cables and fiber optic cables to these enclosures to enable one or more tap offs (e.g., drops) for power connections and also one or more tap offs for fiber data connections for communications devices, such as cellular radios. The enclosure may also function as a pass-through port so that a plurality of nodes may be coupled together in a “daisy chain” manner. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic diagram illustrating the increasing power and data connectivity needs for information and communication technology infrastructure in high density access networks. 
         FIG.  2    is a schematic diagram illustrating an embodiment of a node on a network such as shown in  FIG.  1   . 
         FIG.  3    is a side view of an enclosure used at a network node such as shown in  FIG.  2   . 
         FIG.  4    is a perspective view of a portion of the internal components of the enclosure of  FIG.  3   . 
         FIG.  5    is a top view of the internal components of the enclosure of  FIG.  4   . 
         FIG.  6    is a perspective view of an enclosure with a solar shield according to embodiments of the present inventive concepts. 
         FIG.  7    is a perspective view of an enclosure with another embodiment of the solar shield according to embodiments of the present inventive concepts. 
         FIG.  8    is a top view of a vented enclosure according to embodiments of the present inventive concepts. 
         FIGS.  9 A and  9 B  are top views of embodiments of vents usable in the enclosure of  FIG.  8   . 
         FIG.  10    is a perspective view of the internal components of the enclosure showing a thermal management system according to embodiments of the present inventive concepts. 
         FIG.  11    is a perspective view of the internal components of the enclosure showing a thermal management system according to other embodiments of the present inventive concepts. 
         FIGS.  12  and  13    are detailed perspective views of thermal management system of  FIG.  11   . 
         FIG.  14    is a perspective view showing another alternate embodiment of the solar shield. 
         FIG.  15    is a perspective view showing yet another alternate embodiment of the solar shield. 
     
    
    
     DETAILED DESCRIPTION 
     Pursuant to embodiments of the present inventive concepts, thermal management systems for enclosures for data/power grids are provided. Networks that provide in-line distribution of both power and data to radio nodes and other electronic devices in an outside plant environment are known. The power conductors and optical fibers can be contained in separate cables or in a composite (i.e., combined/hybrid) cable. The purpose of an enclosure for both power conductors and optical fibers is to enable one or more tap offs (e.g., drops) for power connections and also one or more tap offs for fiber data connections for communications devices, such as cellular radios. Such an enclosure may be referred to herein as a “power and fiber enclosure,” a “dual enclosure,” a “composite enclosure,” and/or a “hybrid enclosure.” In embodiments in which the enclosure includes a fiber splice area, the enclosure may be referred to herein as a “power and fiber splice enclosure” or a “fiber optic splice closure.” In some embodiments, the enclosure may also allow a main feed cable to continue to the next location having a tap off, where another enclosure can be installed. Moreover, the terms “closure” and “enclosure” may be used interchangeably herein. 
     According to embodiments of the present inventive concepts, an enclosure may comprise a tray for power conductor termination and power tap off. The enclosure may also comprise another tray for fiber optic termination and data tap off. In some embodiments, another tray may provide fiber optic tube slack (e.g., excess tube) storage. The use of the different trays can provide demarcation between power and fiber, thus enhancing safety. Additional enhancements may, in some embodiments, include (a) using circuit breakers (e.g., miniature circuit breakers) to allow local power down/protection of equipment, (b) surge protection circuitry, and/or (c) a visual indicator (e.g., a warning light) that power is on. For example, having a circuit breaker at each power tap port can facilitate turning off power at an individual power tap port, thus allowing the technician to perform maintenance with respect to the individual power tap port. As used herein, the terms “power tap port” and “power tap off” may be used interchangeably. 
     Cellular operators are beginning to deploy 5G cellular networks in an effort to support the increased cellular data traffic with better coverage and reduced latency. One expected change in the cellular architecture that is anticipated with the deployment of 5G networks is a rapid increase in the number of so-called small cell base stations that are deployed. Generally speaking, a “small cell” base station refers to an operator-controlled, low-power radio access node that operates in the licensed spectrum and/or that operates in the unlicensed spectrum. The term “small cell” encompasses microcells, picocells, femtocells, and metrocells that support communications with fixed and mobile subscribers that are within, for example, between about 10 meters and 300-500 meters of the small cell base station, depending on the type of small cell used. 
     Small cell base stations are typically deployed within the coverage area of a base station of the macrocell network, and the small cell base stations are used to provide increased throughput in high traffic areas within the macrocell. This approach allows the macrocell base station to be used to provide coverage over a wide area, with the small cell base stations supporting much of the capacity requirements in high traffic areas within the macrocell. In heavily-populated urban and suburban areas, it is anticipated that more than ten small cells will be deployed within a typical 5G macrocell to support the increased throughput requirements. As small cell base stations have limited range, they must be located in close proximity to users, which typically requires that the small cell base stations be located outdoors, often on publicly-owned land, such as along streets. Typical outdoor locations for small cell base stations include lamp posts, utility poles, street signs, and the like, which are locations that either do not include an electric power source, or include a power source that is owned and operated by an entity other than the cellular network operator. A typical small cell base station may require between 200-1,000 Watts of power. As small cell base stations are deployed in large numbers, providing electric power to the small cell base station locations represents a significant challenge. 
     One solution that has been proposed for powering small cell base stations is the use of composite power-data cables. Composite power-data cables allow a cellular network operator to deploy a single cable between a hub and a small cell base station that provides both electric power and backhaul connectivity to the small cell base station. The hub may be, for example, a central office, a macrocell base station, or some other network operator owned site that is connected to the electric power grid. All cellular base stations must have some sort of backhaul connection to the core network, and with small cell base stations the backhaul connection is typically implemented as a fiber optic cabling connection. Because the cellular network operator already would typically deploy a fiber optic cable to a new small cell base station installation, changing the fiber optic cable to a power-plus-fiber cable provides a relatively low cost solution for also providing an electric power connection to the new small cell base station. 
     Although using composite power-data cables may be an improvement over more conventional solutions for powering small cell base stations and other remote network-connected devices, deploying long composite power-data cables can be expensive and time-consuming, and hence may not be a completely satisfactory solution. As such, new techniques for providing backhaul and power connectivity to 5G small cell base stations and other remote network-connected device may be beneficial. 
     According to U.S. Patent Application No. 62/700,350, the entire disclosure of which is hereby incorporated by reference herein, power and data connectivity micro grids may be provided for information and communication technology infrastructure, including small cell base stations. These power and data connectivity micro grids may be owned and controlled by cellular network operators, thus allowing the cellular network operators to more quickly and less expensively provide power and data connectivity (backhaul) to new small cell base stations. The power and data connectivity micro grids may be cost-effectively deployed by over-provisioning the power sourcing equipment and cables that are installed, to provide power and data connectivity to new installations, such as new small cell base station installations. 
     The power and data connectivity micro grids may include a network of composite power-data cables that are used to distribute electric power and data connectivity throughout a defined region. These micro grids may be deployed in high density areas, which is where most 5G small cell base stations will need to be deployed. Each micro grid may include a network of composite power-data cables that extend throughout a geographic area. The network of composite power-data cables (and the sourcing equipment supplying the network of composite power-data cables with power and data capacity) may be designed to have power and data capacity far exceeding the capacity requirements of existing nodes along the micro grid. Because such excess capacity is provided, when new remote network-connected devices are installed in the vicinity of a micro grid, composite power-data cables can be routed from tap points along the micro grid to the location of the new remote network-connected device (e.g., a new small cell base station). The newly installed composite power-data cables may themselves be over-provisioned and additional tap points may be provided along the new composite power-data cabling connections so that each new installation may act to further extend the footprint of the micro grid. In this fashion, cellular network operators may incrementally establish their own power and data connectivity micro grids throughout high density areas, which means that when new small cell base stations, WiFi access points, or other remote powered devices are deployed, they will often be in close proximity to at least one tap point along the micro grid. In many cases, the only additional cabling that will be required to power such new base stations is a relatively short composite power-data cable that connects the new small cell base station to an existing tap point of the micro grid. Moreover, by over-provisioning some or all of the newly-installed composite power-data cables, the micro grids may naturally grow throughout high density areas, thus allowing network operators to quickly and inexpensively add new infrastructure to their networks. The composite power-data cables may be implemented as, for example, power-plus-fiber cables, as such cables have significant power and data transmission capacity. Other composite power-data cables (e.g., coaxial cables), however, may additionally and/or alternatively be used. 
     The power delivery component of the power and data connectivity micro grids may comprise a low voltage, direct current (“DC”) power grid in some embodiments. The DC power signals that are distributed over the micro grid may have a voltage that is higher than the (AC) voltages used in most electric utility power distribution systems (e.g., 110 V or 220 V AC), which may help reduce power loss, but the voltage may be lower than 1500 V DC so as to qualify as a low voltage DC voltage under current standards promulgated by the International Electrotechnical Commission (IEC). For example, the micro grid may carry a 380 V DC power signal (or some other DC voltage greater than 48-60 V and less than 1500 V). The 380 V DC power signal may comprise a +/−190 V DC power signal in some embodiments. Tap points may be installed along the composite power-data cables. The tap points, for example, may comprise intelligent remote distribution nodes that include a gated pass-through power bus that allows for daisy chain operation and/or splitting of the power signal, as well as one or more local ports that may be used to power remote powered devices that are co-located with the intelligent remote distribution node or in close proximity thereto. 
     The tap points may comprise splice enclosures that are installed along the composite power-data cables. These splice enclosures may include terminations for both the optical fibers and power conductors of the composite power-data cables. The splice enclosures may provide connection points for “branch” composite power-data cables that supply power and data connectivity to existing installations that are connected to the micro grid, may include a gated pass-through power bus, and/or may act as tap points for future installations. 
       FIG.  1    is a schematic diagram illustrating the increasing power and data connectivity needs for information and communication technology infrastructure in high density access networks. As shown in  FIG.  1   , in an urban or suburban environment  100 , a telecommunications provider, such as a cellular network operator, may operate a central office  110  and a macrocell base station  120 . In addition, the telecommunications provider may operate a plurality of small cell base stations  130 , WiFi access points  140 , fixed wireless nodes  150 , active cabinets  160 , DSL (e.g., G.fast) distribution points  170 , security cameras  180 , and the like. All of these installations may require DC power to operate active equipment, and most, if not all, of these installations may also require data connectivity either for backhaul connections to the central office  110  and/or for control or monitoring purposes. It may be both expensive and time consuming to provide local power sources for these installations. 
     To reduce costs and increase the speed at which electric power and data connectivity can be deployed to remote network-connected powered devices such as the remote devices  130 ,  140 ,  150 ,  160 ,  170 ,  180  illustrated in  FIG.  1   , the use of power-plus-fiber cables has been proposed. For example, PCT Publication No. WO 2018/017544 A1, which is incorporated herein in its entirety by reference, discloses an approach for providing power and data connectivity to a series of remote powered devices in which power—plus-fiber cables extend from a power source to a plurality of intelligent remote distribution nodes. Each intelligent remote distribution node may include a “pass-through” port so that a plurality of remote distribution nodes may be coupled to the power source in “daisy chain” fashion. Intelligent remote powered devices may be connected to each intelligent remote distribution node and may receive power and data connectivity from the intelligent remote distribution node. 
     One drawback of the approach disclosed in PCT Publication No. WO 2018/017544 A1 is that as new installations are deployed, it is necessary to install another power-plus-fiber cable that runs from the power source to the new installation. Deploying such power-plus-fiber cables can be time consuming and expensive, particularly in urban environments. 
     According to U.S. Patent Application No. 62/700,350, the power source equipment and remote distribution node approach disclosed in PCT Publication No. WO 2018/017544 A1 may be extended so that cellular network operators may create a hard wired power and data connectivity micro grid throughout high density urban and suburban areas. As new installations (e.g., new small cell base stations  130 , security cameras  180 , and the like) are deployed in such areas, the cellular network operator may simply tap into a nearby portion of the micro grid to obtain power and data connectivity without any need to run cabling connections all the way from the power and data source equipment to the new installation. The micro grids may be viewed as being akin to the backplane on a computer, as the micro grids extend throughout the area in which power and data connectivity are required and have excess power and data connectivity resources available so that new installations may simply “plug into” the micro grid at any of a large number of tap points. 
     Referring to  FIG.  2   , a schematic view of an embodiment of a portion of a network architecture is shown. A plant  200  provides distributed power from a power source  202  and data from a data source  204  to the network. The power and data may be delivered using hybrid power-data cables  300  to nodes  208  on the network. In the illustrated embodiment the node  208  is a small cell base station comprising radios  212  mounted on a support structure  214  such as a tower. In some embodiments, the enclosure  500  defines a tap point that may be provided along the composite power-data cable  300  that allow for daisy chain operation and/or splitting of the power and data signals. As shown in  FIG.  2   , enclosure  500  separately delivers the power and data to the equipment at the node. The data may be delivered over a separate data line  218  such as a fiber optic cable. The power may be delivered using a power cable  400 . Separating the power and data at the node may be necessitated by the service provider&#39;s equipment architecture. Separating the power and data at the node also may facilitate maintenance and repair. 
     An embodiment of an enclosure  500  is shown in  FIG.  3   . In the illustrated embodiment the enclosure  500  includes a fiber splice area and may be referred to as a fiber optic splice closure or “FOSC.” An embodiment of one such enclosure is described in application WO 2020/040913, entitled “Hybrid Enclosures for Power and Optical Fiber and Enclosures Including Multiple Protective Lids” filed Jul. 19, 2019 by CommScope Technologies LLC to Thomas et al. which is incorporated by reference herein in its entirety. The enclosure  500 , which may also be referred to herein as a “closure,” may include a polymer (e.g., plastic) housing  502  defined by a base portion  510  and a polymer dome  511 , or other structure, that can releasably attach to the base portion  510  to enclose the internal structure of the enclosure. The enclosure  500  may thus protect the elements within the enclosure  500  from weather, wildlife, and other elements that should not contact the trays internal components. The internal structure of the enclosure  500  may be accessed by removing the dome  511  from the base portion  510 . 
       FIGS.  4 ,  5  and  10    show an embodiment of the internal structure of an enclosure  500  such as shown in  FIG.  3   . In one embodiment, a plurality of trays  512 ,  513  and  514  may be attached to an attachment structure  515 . In some embodiments, the trays  512  and  513  may be hingedly coupled to respective portions of the attachment structure  515  so that a technician can more easily access one of the trays while the trays are attached to the attachment structure  515 . For example, such hinged/tiltable coupling to the attachment structure  515  may allow the technician to access a particular one of the trays  512 - 514  in a manner that reduces disturbance to others of the trays. In use, the trays  512 - 514  can be stacked on top of one another while the trays are attached to the attachment structure  515  as shown in  FIG.  10   . 
     The trays  512  and  513  may be trays for fiber connection and/or storage. The trays  512 ,  513  may hold one or more fiber optic tubes. The tray  514  may be a tray for power connectivity and may hold one or more power cables. A greater or fewer number of trays may be provided in various combinations of fiber connection/storage trays and power connection/storage trays. In addition to protection provided by the enclosure  500 , one or more of the trays  512 - 514  may be further protected by tray lids. 
     One or more optical fiber splice areas/terminals may be in (e.g., attached to) the trays  512  and/or  513 . Optical fibers (e.g., from one or more fiber optic tubes in composite cable  300 ) may be connected to the optical fiber splice areas/terminals, which thus may be referred to herein as “optical fiber tap offs.” For example, the tray  512  may comprise one or more optical fiber splice modules, each of which includes an area in which a plurality of optical fiber connections can be made. The tray  513  may comprise an optical fiber storage tray/area. For example, the tray  513  may have storage capacity for at least one meter, or at least two meters, of length of one or more fiber optic tubes. 
     The tray  514  may house one or more power ports  520  to which power cables  522  are electrically connected. The power ports  520  may comprise a power-in port and a power-out port, respectively, and some of the power ports may be power tap ports. As an example, a voltage at each power-in/out port may be 380 V DC (e.g., +/−190 V DC on the two power conductors), and the power tap ports may feed adjacent utility poles and/or other remote nodes. The power ports  520  may comprise connector blocks; however, each power port may comprise any type of electrical port and is not limited to a connector block. Accordingly, the power ports may be connectorized or non-connectorized ports. Additionally or alternatively, the tray  514  may house circuit breakers that comprise, or are electrically coupled to, the power ports  520 . For example, the circuit breakers can be used in the place of connector blocks. The circuit breakers can facilitate individually turning off power at one or more of the power ports instead of turning off power to the entire group. 
     The power ports  520  may be on power circuitry  518 . For example, the power circuitry  518  ( FIG.  5   ) may be a printed circuit board, or other wiring, that provides electrical connections for the power ports. As an example, the power circuitry  518  may electrically connect ground components of the cables from the power ports to a common ground connection. Additionally or alternatively, the power circuitry  518  may be configured to supply data, and/or power that exceeds 150 Watts, to and/or from the power ports. Although some devices, such as security cameras  180  ( FIG.  1   ) or WiFi access points  140  ( FIG.  1   ), can operate with power that is lower than 150 Watts, most devices that are coupled to the power ports  240  are configured to use power that exceeds 150 Watts. One example is small cell base stations  130  ( FIG.  1   ), which may use power between about 200 and about 1,000 Watts. 
     Moreover, although the above-description describes an example enclosure in which, for safety purposes, the power ports  520  are separate from the optical fiber tap offs in tray  513 , in some embodiments in which the ports are connectorized, the ports  520  may be combination ports that include both a power conductor terminal and an optical fiber tap off in the same connector block. 
     The enclosures  500  may be installed at locations where intelligent remote distribution nodes (“IRN”) or other remote distribution nodes are deployed. The enclosures  500  may be installed, for example, underground or above ground. One pair of a power output port and a data output port may be viewed as a “pass-through” ports that allow the enclosures to be daisy-chained together. The remaining pairs of power and data output ports may be viewed as “tap” ports that may be used to provide power and data connectivity to individual remote network-connected devices (or co-located groups thereof). When a new remote powered device, such as a small cell base station, is to be deployed, an intelligent remote distribution node may be installed at the site for the new small cell base station (e.g., on a utility pole where the small cell radio and antenna are mounted). A power-plus-fiber cable may then be deployed between the newly-installed intelligent remote distribution node and the closest enclosure  500  of the power and data connectivity micro grid, and a short jumper cable (or cables) may connect the intelligent remote distribution node to the small cell radio. The enclosure  500  may be designed to output DC power signals (e.g., 380 V DC) to each output port thereof (i.e., the pass-through port and the tap ports). The intelligent remote distribution node may include step-down equipment, such as a buck converter, that reduces the voltage level of the DC power signals delivered thereto from the enclosure  500  to a level that is suitable for powering the remote powered device. The intelligent remote distribution nodes may or may not include pass-through power buses that allow daisy-chaining multiple intelligent remote distribution nodes together. Moreover, in some embodiments some or all of the functionality contained in the intelligent remote distribution nodes may be moved to the enclosure  500  such that the enclosure  500  may include the electronics, such as the buck converter, that reduces the voltage level of the DC power signals delivered from the enclosure  500  to a level that is suitable for powering the remote powered device. 
     To supply data connectivity to a newly-installed node  208 , such as a small cell base station, one or more of the optical fibers of power-plus-fiber cable  300  may be spliced in the enclosure  500  to connect to a data tap port of the enclosure  500 . The data tap port of the enclosure  500  may be connected to a data input port on the node  208  via, for example, a fiber cable  218  or by a composite power-data cable. The power tap port of the enclosure  500  may be connected to a power input port on the node  208  via, for example, a power cable  400  or by a composite power-data cable. In this fashion, the enclosure  500  may provide power and data connectivity to the node  208  such as a small cell base station. 
     The splice enclosure  500  may provide a plurality of tap points along each power-plus-fiber cable, thereby providing numerous locations where the cellular network operator may tap into the micro grid to provide power and data connectivity for future installations. The enclosures  500  may be pre-installed along the power-plus-fiber cables, or slack loops may be included in the power-plus-fiber cables and the splice enclosures  500  may be installed later as needed. 
     An enclosure, such as enclosure  500  such as described above, includes active electronic elements that generate heat. Moreover, such enclosures are typically located outside and above-ground such that the enclosures  500  can be easily accessed by technicians. One issue with outside located enclosures is that heat generated by the sun&#39;s radiation also increases the temperature inside of the enclosure  500 . As a result, thermal management of enclosures such as the enclosure  500  described herein is required. 
     Referring to  FIG.  6   , in a first embodiment, a solar shield  600  may be deployed over the enclosure  500  that prevents solar radiation from reaching the enclosure  500 . The solar shield  600  may be any suitable radiant barrier that reflects thermal radiation and reduces heat transfer to the enclosure  500 . The solar shield  600  may be made of aluminum or other reflective metal. The solar shield  600  may also be made of a rigid reflective plastic such as white thermoplastic. The solar shield  600  may also be made of a composite material such as a plastic base layer covered by a reflective material such as a metal film. The solar shield  600  may also be made of a reflective fabric, reflective film or other flexible material supported by a rigid frame. In some embodiments, the exterior surface  600   a  of the solar shield  600  may be made diffusive such that the light reflected by the solar shield is reflected in a diffuse manner such that glare spots are not created. The exterior surface  600   a  of the solar shield  600  may be made diffusive by applying a diffusive material to the exterior surface  600   a , by using a material having diffusive properties such as white plastic, by providing the surface  600   a  with a diffusive finish such as by etching, or the like. 
     The solar shield  600  may have a tent-like configuration that partially encircles the enclosure  500  and that covers the top and side portions of the enclosure  500  but that leaves the bottom portion of the enclosure  500  uncovered as shown in  FIG.  6   . Because the solar shield  600  is used to prevent heating of the enclosure  500  caused by the sun&#39;s radiation, the solar shield  600  need only be located over areas of the enclosure  500  that would be exposed to the sun&#39;s radiation when the enclosure  500  is deployed in the field. The solar shield  600  may be formed of a plurality of panels  602 ,  604 ,  606 ,  608  and  610  that are connected together at joints  603  to form the complete solar shield  600 . The solar shield  600  as shown in  FIG.  6    comprises a top panel  602  with two side panels  604 ,  606  and two end panels  608 ,  610  extending from the top panel  602  at joints  603  at a downward angle therefrom. The solar shield  600  may include a fewer or greater number of panels that define any open polygonal shape. For example, the solar shield  600  may have a substantially inverted V-shape or other open polygon shape. The solar shield  600  may formed as an integral, one-piece member such as a sheet of aluminum bent at joints  603  to create the solar shield  600  such as in a metal forming process such as extrusion, stamping, rolling or the like, or by being molded in one-piece of plastic or polymer in an injection molding, extrusion or similar process. Alternatively, the panels may be separate panels joined together to create the solar shield  600 . Moreover, while the illustrated solar shield  600  has a rectilinear shape formed by flat panels  602 ,  604 ,  606 ,  608  and  610 , the panels may be curved in one or more planes. Another example embodiment of the solar shield  600   a  is shown in  FIG.  15   . The solar shield  600   a  is formed by three flat panels  602   a ,  604   a  and  606   a  arranged in an inverted open box structure. The solar shield may also have a continuous surface uninterrupted by joints such as a continuously curved surface. For example, the solar shield  600   b  may have a substantially inverted U-shape, as shown in  FIG.  14   , that is a continuous curve. In other embodiments, the solar shield  600  may completely encircle the enclosure  500  where the solar shield  600  is shaped in cross-section as a circular, oval, octagon, hexagon, other polygon shapes, or the like. 
     In some embodiments, the solar shield  600  completely covers the surfaces of the enclosure  500  that would otherwise receive the sun&#39;s radiation. However, small portions of the enclosure  500  may be left uncovered and still obtain the benefits of using the heat shield. In this manner, the solar shield  600  covers a major portion of the enclosure  500  where the major portion of the enclosure  500  covered by the solar shield  600  is sufficient to prevent overheating of the enclosure  500  caused by the sun&#39;s radiation. A hole or a plurality of holes  613  may be formed in the top of the solar shield  600  ( FIG.  15   ) to create a chimney affect that pulls the cool air between the enclosure  500  and the solar shield  600  to aid in the dissipation of heat which is created primarily from the solar shield  600  due to the exposure to the sun, but is also created by heat that is generated within the enclosure  500  and dissipated through the walls of the enclosure  500 . 
     In some embodiments, the solar shield  600 , when mounted over the enclosure  500 , is spaced from the enclosure  500  such that an air gap  616  is created between the solar shield  600  and the enclosure  500 . Providing the air gap  616  prevents the conduction of heat directly from the solar shield  600  to the enclosure  500 . In some embodiments, the solar shield  600  may be formed to create the air gap  616 . For example, as shown in  FIG.  6    the front end panel  608  and the back end panel  610  may be shaped to engage the enclosure  500  in a manner that spaces the majority of the solar shield  600  from the enclosure  500 . Spacers may also be provided on the underside of the solar shield  600  to create the air gap  616 . The spacers may comprise separate members connected to one of the solar shield  600  and the enclosure  500  or the spacers may be formed as one-piece with the solar shield  600 . For example, a solar shield  600  made of molded plastic may have spacers formed as one piece therewith during the molding process. Likewise, a solar shield  600  made of a sheet of metal may have the spacers punched and bent out of the metal sheet as part of the metal forming process. Moreover, a suitable air gap may be created by the shape of the enclosure  500  itself. For example, as shown in  FIG.  3   , the enclosure  500  may be formed with a fins  520  where the solar shield  600  may sit on the fins  520  if the heat transferred to the enclosure  500  due to contact with the solar shield  600  is acceptably low. 
       FIG.  3    shows a common mounting structure for an enclosure  500  where the enclosure  500  is mounted on a support  622  such as a pole, cable or wire by connectors  620  such as straps, flanges that may be made of any suitable material such as metal, plastic or combinations of such materials. The solar shield  600  may be provided with openings  624  ( FIG.  6   ) on a top portion thereof such that the connectors  620  can extend through the openings  624  to trap the solar shield  600  between the support  622  and the enclosure  500 . The solar shield  600  may further include openings  626  for receiving flanges  524  formed on the enclosure  500 . In some embodiments, existing enclosures  500  are provided with such flanges  524  as part of their mounting structure. The solar shield  600  may be designed with mating apertures  626  to receive the existing flange structures  524  on the enclosures  500 . The location, size, shape, etc. of the flanges  524  may differ from those shown in  FIG.  3    and the mating apertures  626  may be designed to mate with the flanges  524 . Fasteners  628 , such as bolts, straps, zip ties, cotter pins or the like, may be used to engage apertures  526  formed on the flanges  524  and fix the solar shield  600  to the enclosure  500 . In other embodiments, the solar shield  600  may be secured to the enclosure  500  by separate fasteners such as metal straps or zip ties that encircle the solar shield  600  and the enclosure  500 . 
     Because the enclosure  500  is in a fixed position relative to the support  622 , the solar shield  600  may be connected to the support  622  and/or the connectors  620  rather than directly to the enclosure  500 . Alternatively, the solar shield  600  may be connected to both of the enclosure  500  and the support  622 . The solar shield  600  may be connected to the support  622  and/or the connectors  620  using various connection devices. For example, if the support  622  is a pole the connection mechanism may comprise a pole clamp, if the support  622  is a cable or wire the connection mechanism may comprise a cable clamp, and where the support  622  is a building or other structure the solar shield  600  may be connected to the building by screws or the like. The solar shield  600  may also be connected to connectors  620  using clamps, bolts, screws or the like. 
     In some embodiments, the enclosure  500  may be mounted other than horizontally where the long axis of the enclosure  500  extends other than horizontally. In such an embodiment, the solar shield  600  may be disposed at least partially over the exposed end of the enclosure  500 . The solar shield  600  may include an aperture or apertures to allow the cables  630  to pass through the solar shield  600 . In any orientation of the enclosure  500 , the solar shield  600  is disposed between the enclosure  500  and direct light from the sun to reflect radiated solar energy before it reaches the enclosure  500 . 
     Referring to  FIG.  7   , in one embodiment, the solar shield  600  may include indicators  630  such as color-coded stripes that indicate if the enclosure  500  contains electrical power to alert technicians, emergency personnel or others of the status of the enclosure  500 . The indicators  630  may be formed by tape, cable wrap, colored zip ties, paint or the like. 
     Referring to  FIGS.  8 ,  9 A and  9 B , in another embodiment, vents  700  may be provided in the housing  502  of the enclosure  500  to vent hot air from the enclosure  500 . The vents  700  may be used with or without the solar shield  600  described above depending on the heat management requirements of the system. In one embodiment, the vents  700  are placed on the side of the housing  502  that faces upward when the enclosure  500  is installed such that the system takes advantage of the rising heat in the enclosure to vent the hot air via vents  700 . While two separate vents  700  are shown in  FIG.  8   , a greater or fewer number of vents  700  may be used and the size and shape of the vents may vary from the vents  700  as shown in  FIGS.  8 ,  9 A and  9 B . In some embodiments, the vents  700  may comprise a polycarbonate frame  702  covered by a waterproof membrane  704  such that water is prevented from entering the enclosure through the vents  700  but air is allowed to flow out of the vents  700 . The membrane  704  may be a water tight ePTFE membrane. The vents  700  also balance the air pressure within the enclosure  500 . The use of the solar shield  600  with the vents  700  provides further protection against rain entering the enclosure  500  via the vents  700 . 
     Reference is made to  FIGS.  10  through  13    which show an embodiment of a cooling condenser thermal management system  800  for use in an enclosure  500 . The cooling condenser thermal management system  800  may be used with or without either or both of the vents  700  and solar shield  600  as described above.  FIGS.  10  and  11    show the internal structure of the enclosure  500  with the outer housing  502  removed. Moreover, the structure as shown in  FIGS.  10  through  13    is shown in an inverted or upside-down orientation to better illustrate the cooling condenser thermal management system  800 . In actual use, the structure is typically rotated 180 degrees such that the thermal management system  800  is disposed toward the bottom of the enclosure  500 . The cooling condenser thermal management system  800  comprises a heat sink structure  802  that is thermally coupled to the internal structure of the enclosure  500 . In the illustrated embodiment, the heat sink structure  802  is mounted to the outside surface of a metal, or otherwise thermally conductive, plate  804  that is thermally coupled to the power tray  514 . The power components in the power tray  514  are thermally coupled to the plate  804  such that the heat sink structure  802  is thermally coupled to the heat generating internal power components. The heat sink structure  802  may comprise a substantially solid heat sink block  808  made of a thermally conductive material such as aluminum, copper or other metal, thermally conductive plastic or the like. The heat sink structure  802  may be thermally coupled to any heat conducting or heat producing component of the enclosure  500 . 
     At least one, and in the illustrated embodiment two, condenser pipes  806  are engaged with the heat sink block  808 . While two condenser pipes  806  are shown a greater or fewer number of condenser pipes  806  may be used. Moreover, while the two condenser pipes  806  are connected to a single heat sink block  808 , a separate heat sink block  808  may be provided for each condenser pipe  806 . The heat sink block  808  includes at least one internal conduit (not visible in  FIGS.  11  and  13   ) that is fluidly coupled to the condenser pipes  806  such that fluid can flow between the internal conduits of heat sink block  808  and the condenser pipes  808 . In some embodiments, a single internal conduit may be connected to both condenser pipes  806  or each condenser pipe  806  may connect to a separate internal conduit. The internal conduit(s) may be formed as bores formed in the heat sink block  808  and the condenser pipes  806  may connect to the bores at the exterior of the heat sink block  808 . Alternatively, the condenser pipes  806  may extend into the bores and be thermally coupled to the heat sink block  808 . 
     The condenser pipes  806  extend to the exterior of the enclosure  500  such that a portion  806   a  of each of the condenser pipes  806  is exposed to the ambient environment. The condenser pipes  806  may extend through apertures in the cap  810  and seals or gaskets  812 , such as gel pack seals, may be used to seal the apertures. A working fluid is contained in the condenser pipes  806 . The working fluid may be any suitable fluid such as water, alcohol, refrigerants, or the like, and/or any fluid that is commonly used in heat pipes, pumped refrigerant and thermosyphon systems]. In operation, the liquid working fluid in the condenser pipes is heated by the heat conducted to the heat sink block  808  and is evaporated to form a gas. The condenser pipes  806  are configured such that the gas travels through the condenser pipes  806  to the exterior of the enclosure  500 , the gas is cooled by heat transfer to the surrounding ambient air and condenses back to the liquid state, the liquid working fluid in the exposed portions  806   a  of the condenser pipes  806  flows back to the heat sink block  808 , and the process is continuously repeated. As shown in  FIGS.  11 - 13   , the condenser pipes  806  may have any suitable dimensions and the exposed, external portions  806   a  of the condenser pipes  806  may have different dimensions than the internal portion of the condenser pipes  806 . For example, the external portions  806   a  of the condenser pipes of  FIG.  11    is thicker than the external portions  806   a  of the condenser pipes  806  of  FIG.  10    to facilitate heat transfer to the ambient environment. The external portions  806   a  shown in  FIG.  11    may be provided by using a separate section of pipe or by adding the larger section of pipe over the narrower pipe section provided that the separate pipe components are thermally coupled to one another. 
     The use of thermal management system  800  provides localized cooling for any component that is thermally coupled to the heat sink structure  802 . Moreover, the thermal management system  800  provides cooling of the air in the enclosure. 
     The present inventive concepts have been described above with reference to the accompanying drawings. The present inventive concepts are not limited to the illustrated embodiments. Rather, these embodiments are intended to fully and completely disclose the present inventive concepts to those skilled in this art. In the drawings, like numbers refer to like elements throughout. Thicknesses and dimensions of some components may be exaggerated for clarity. 
     Spatially relative terms, such as “under,” “below,” “lower,” “over,” “upper,” “top,” “bottom,” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “under” or “beneath” other elements or features would then be oriented “over” the other elements or features. Thus, the example term “under” can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. 
     Herein, the terms “attached,” “connected,” “interconnected,” “contacting,” “mounted,” and the like can mean either direct or indirect attachment or contact between elements, unless stated otherwise. 
     Well-known functions or constructions may not be described in detail for brevity and/or clarity. As used herein the expression “and/or” includes any and all combinations of one or more of the associated listed items. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present inventive concepts. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including” when used in this specification, specify the presence of stated features, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, operations, elements, components, and/or groups thereof.