EVAPORATOR SHROUD AND ASSEMBLY FOR A DIRECT CURRENT AIR

CONDITIONING SYSTEM

GOVERNMENT RIGHTS

[0001] This invention was made with Government support under contract DE-FC26-04NT42106, awarded by the United States Department of Energy. The Government may have certain rights in this invention.

FIELD

[0002] The present disclosure relates to direct current (DC) air conditioning systems including an evaporator shroud and evaporator assembly for a DC air conditioning system.

BACKGROUND

[0003] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0004] Direct current (DC) environmental temperature control systems (ETCSs), also referred to as air conditioning systems, are often used to control the temperature within enclosed environments where alternating current (AC) ETCSs are not feasible, desirable or reliable. For example, in environments enclosed by structures that are remotely located where AC power is not available or conveniently accessible, or where a backup air conditioning system is necessary in case AC power is interrupted, or where a DC air conditioning

system is more desirable than an AC air conditioning system. Generally, DC air conditioning systems have a capacity suitable for efficiently controlling the temperature of environments enclosed by smaller structures or buildings. For example, DC air conditioning systems are very suitable for controlling the temperature within utility sheds, portable or mobile structures, and electronics cabinets and utility or equipment structures such as cellular wireless communication electronic cabinets and battery backup closets.

[0005] Such smaller structures can be located in a wide variety of outdoor locations that present a myriad of rigorous exterior environmental conditions that affect the temperature within the structures. That is, the structures can be exposed to a wide range of external temperatures, e.g., -30°C to 55°C, varying solar loads and various forms of precipitation that can all affect the internal environmental temperature. In the case of equipment cabinets, temperature control requirements can be stringent in order to prevent damage to the often expensive and not terribly rugged equipment inside. Thus, employment of DC air conditioning systems is often desirable for actively controlling the temperature enclosed environment of such smaller structures. And in many cases, efficiency, consistency and reliability are critical necessities of the DC air conditioning system.

[0006] Typically, DC air conditioning systems include a condenser assembly and an evaporator assembly. In operation, the evaporator assembly receives air from an enclosed environment, and an air mover pushes the air across a heater or an evaporator heat exchanger to condition the air (i.e., to heat

or cool the air) before outputting the air back into the enclosed environment. The evaporator assembly typically is mounted in a sheet metal box, the exterior of which is exposed to external environmental elements such as water, humidity, salty air, insects, dust, pollen, and/or electromagnetic radiation. Insulating the enclosed environment from such external environmental elements is important, since the ingress of such elements can damage equipment inside the enclosed environment as well as the evaporator assembly.

[0007] As recognized by the inventors, however, mounting the evaporator in a sheet metal box provides disadvantages. For example, sheet metal boxes are formed first by bending and folding sheet metal to form sides having edges, the edges are then sealed using a sealant, such as a room temperature vulcanizing (RTV) sealant. These seals are time consuming to apply, costly and prone to failure. Over time the seals may tear or break causing leaks, which may lead to the ingress of the external environmental elements discussed above.

[0008] In addition, the sheet metal box, due to its rectangular shape, may provide poor airflow through the evaporator assembly, thus compromising its heating and/or cooling performance.

SUMMARY

[0009] According to one aspect of the present disclosure, an evaporator shroud for a direct current (DC) powered variable capacity air conditioning system having an evaporator assembly and a condenser assembly.

The system further includes an air intake opening for intaking air from an enclosed environment into the evaporator assembly and an air output opening for outputting air from the evaporator assembly into the enclosed environment. The evaporator shroud includes a single seamless structure positioned adjacent the air intake opening and the air output opening and defining an air passage between the air intake opening and the air output opening.

[0010] According to another aspect of the present disclosure, a direct current (DC) powered variable capacity air conditioning system having an evaporator assembly and a condenser assembly. The system further includes an air intake opening for intaking air from an enclosed environment into the evaporator assembly and an air output opening for outputting air from the evaporator assembly into the enclosed environment. Additionally, the system includes a housing defining the air intake opening and the air output opening, and an evaporator shroud. The evaporator shroud is secured in the housing and positioned adjacent the air intake opening and the air output opening and defines an air passage between the air intake opening and the air output opening. The evaporator shroud further comprises a single piece seamless structure.

[0011] According to yet another aspect of the present disclosure, a direct current (DC) powered variable capacity air conditioning system having an evaporator assembly and a condenser assembly. The system further includes an air intake opening for intaking air from an enclosed environment into the evaporator assembly and an air output opening for outputting air from the evaporator assembly into the enclosed environment. Additionally, the system

includes a housing defining the air intake opening and the air output opening, an evaporator heat exchanger, an evaporator air mover and an evaporator shroud. The evaporator shroud includes an evaporator heat exchanger section positioned adjacent the evaporator heat exchanger and an evaporator air mover section positioned adjacent the evaporator air mover. The evaporator air mover section is configured for channeling air from the air intake opening to the evaporator heat exchanger section. The evaporator heat exchanger section is configured for channeling the air substantially uniformly across the evaporator to the air output opening.

DRAWINGS

[0012] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

[0013] Fig. 1 is a block diagram of a direct current (DC) powered variable capacity air conditioning system (VCACS) including an evaporator shroud according to various embodiments of the present disclosure, connected to a structure enclosing an environment to be thermally conditioned by the variable capacity air conditioning system;

[0014] Fig. 2 is an exploded perspective view of a portion of the VCACS illustrating various components of the VCACS, in accordance with various embodiments of the present disclosure;

[0015] Fig. 3 is a front view of an evaporator shroud according to various embodiments of the present disclosure;

[0016] Fig. 4 is a side view of the evaporator shroud of Fig. 1 in accordance with various embodiments of the present disclosure;

[0017] Fig. 5 is a perspective view of the evaporator shroud of Fig. 1 in accordance with various embodiments of the present disclosure;

[0018] Fig. 6 is a blown up view of section A, shown in Fig. 5, illustrating condensation collectors in detail in accordance with various embodiments of the present disclosure;

[0019] Fig. 7 is a side view of a portion of a direct current (DC) powered variable capacity air conditioning system according to other embodiments of the present disclosure.

DETAILED DESCRIPTION

[0020] Further areas of applicability of the present disclosure will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating various preferred embodiments, are intended for purposes of illustration only and are not intended to limit the scope of the disclosure. Additionally, the features, functions, and advantages of the present disclosure can be achieved independently in various embodiments or may be combined in yet other embodiments.

[0021] Fig. 1 illustrates a direct current (DC) powered variable capacity air conditioning system 10 having an evaporator shroud 32 according to one or

more embodiments described below. The DC variable capacity air conditioning system (VCACS) 10 is connected to a wall of a structure 14 enclosing an environment 18 to be thermally conditioned by the DC VCACS 10. The DC VCACS 10 can operate using any suitable DC power supply (not shown) such as one or more DC batteries or a converted alternating current (AC) supply. The structure 14 can be any building, shed, cabinet, closet, portable or mobile structure, or any other structure enclosing an environment desirous of being thermally controlled by the DC variable capacity air conditioning system 10. For example, the structure 14 can be an electronics and/or equipment cabinet, such as a cellular wireless communication electronics cabinet or battery backup closet, where it is important to maintain the enclosed environment 18 at a desired temperature to prevent damage to the enclosed components and/or systems. The VCACS 10 is configured to provide heating and cooling to maintain a substantially constant temperature of the enclosed environment 18 of the structure 14. The VCACS 10 and the structure 14 can comprise a telecommunication station, e.g., a wireless telecommunication station, wherein the structure 14 is a telecommunication electronics and equipment cabinet, e.g., a wireless telecommunication electronics and equipment cabinet.

[0022] The VCACS 10 generally includes a housing 12 enclosing a condenser assembly 34 and an evaporator assembly 38 and a variable speed compressor 42 connected to the condenser and evaporator assemblies 34 and 38 via refrigerant lines 46. The housing 12 defines an air intake opening 17 for intaking air from the enclosed environment 18 into the evaporator assembly 38

(indicated generally by an arrow 16), and an air output opening 19 for outputting air from the evaporator assembly 38 into the enclosed environment 18 (indicated generally by an arrow 20). The evaporator shroud 32, described in more detail below, defines an air passage 24 between the air intake opening 17 and the air output opening 19.

[0023] Referring to Fig. 2, in various embodiments, the evaporator assembly 38 includes an evaporator heat exchanger 50, a heating mechanism 54, an evaporator air mover 58 and a circuit board 62, all of which are mounted to the evaporator shroud 32. The evaporator air mover 58 can be rotationally mounted to an evaporator air mover mounting plate 66, which can then be mounted to the evaporator shroud 32. The evaporator air mover 58 can be a radial fan, an axial fan or a turbine, a variable speed backward-curved impeller, or any air mover suitable for moving varying capacities of air. Furthermore, the heating mechanism 130 can be any suitable heat producing mechanism such as an open wire resistive heater, radiator type heater, a chemical reaction type heater, or any other heating device.

[0024] The housing 12 can include a housing panel 70 and a housing hood 74. The housing panel 70, in various embodiments, is mounted over the evaporator air mover 58, evaporator heat exchanger 50, heating mechanism 54 and circuit board 62 and coupled to the evaporator shroud 32 and/or a housing hood 74. The housing panel 70 includes the air intake opening 17 and a plurality of grated or finned apertures that generally form the air output opening 19. In various embodiments, an evaporator air mover cover 60 can be positioned over

the housing panel 70, thereby covering at least a portion of the air intake opening 17.

[0025] In various embodiments, the evaporator shroud 32 is formed or fabricated as a single piece, seamless structure. For example, the evaporator shroud 32 can be molded using thermal forming or injection molding, cast, stamped or pressed to form a single piece structure without folded edges or joint seams.

[0026] In addition, the evaporator shroud 32 can be fabricated from any suitable material such as any suitable plastic polymer or composite, any suitable reinforced polyurethane or epoxy resin or any other material suitable for fabricating a single piece seamless evaporator shroud 32.

[0027] Referring now to Figs. 3-5 and 7, the evaporator shroud 32 includes an evaporator air mover section 78 positioned adjacent the air intake opening 17, and an evaporator heat exchanger section 82 positioned adjacent the air output opening 19. The evaporator air mover section 78 includes mounts 86 for supporting the evaporator air mover 58 as well as mounts 90 for supporting the circuit board 62 positioned below the mounts 86. The evaporator heat exchanger section 82 includes mounts 94 for supporting an evaporator heat exchanger 50 and mounts 98 for supporting the heating mechanism 54. The mounts 94 and 98 are positioned below the mounts 86.

[0028] The evaporator air mover 58, the circuit board 62, the evaporator heat exchanger 50, and the heating mechanism 54 can be secured to the mounts 86, 90, 94 and 98, respectively, via a plurality of fasteners 102, as

best shown in Fig. 7, which are inserted into fastener openings 106. The fasteners 102 may be any suitable fastener including, without limitation, screws, nails, rivets or bolts.

[0029] In various embodiments, the evaporator air mover section 78 receives air from the air intake opening 17 and channels the air to the evaporator heat exchanger section 82. The evaporator heat exchanger section 82 then channels the air received from the evaporator air mover section 78 substantially uniformly, as best shown in Figs. 4 and 7, across the evaporator heat exchanger 50 and then through the air output opening 19.

[0030] The evaporator heat exchanger section 82 can include a curved surface 118 having a bump portion 122 and a tapered portion 126. The bump portion 122 allows the evaporator shroud 32 to output air through an upper portion of the evaporator heat exchanger 50, while the tapered portion 126 allows the evaporator shroud 32 to output air through middle and bottom portions of the evaporator heat exchanger 50. Substantially uniform airflow through the evaporator heat exchanger 50 generally increases the performance of the evaporator heat exchanger 50.

[0031] Although, the curved surface 118 includes a bump portion 122 and a tapered portion 126, in various other embodiments, the curved surface 118 may include a single smooth curved contour absent the bump portion 122 and/or the tapered portion 126 without departing from the scope of this disclosure.

[0032] The evaporator air mover section 78, in various embodiments, includes a curved portion 130 which surrounds the evaporator air mover 58.

When air enters the evaporator assembly 38 through the air intake opening 17, the evaporator air mover 58 pushes the air radially away from the center of the evaporator air mover 58. The air subsequently collects in, and is then channeled downwardly by the curved portion 130 of the evaporator air mover section 78 to the evaporator heat exchanger section 82. The curved portion 130 allows air to flow from the air intake opening 17 downwardly through the evaporator shroud 32 smoothly.

[0033] In various embodiments, the circuit board 62 is supported in the evaporator shroud 32 and is positioned in the air passage 24 downstream of the evaporator air mover 58. The circuit board 62 includes a plurality of components 134, as best shown in Fig. 7. The air channeled downwardly by the curved section 130 of the evaporator air mover section 78 passes over the circuit board 62 and its components 134, thereby cooling the components 134.

[0034] Although the circuit board 62 is positioned downstream of the evaporator air mover 58, it should be understood that the circuit board 62 may be positioned elsewhere in the air passage 24 without departing from the scope of this disclosure.

[0035] The components 134 of the circuit board 62 may be various electrical elements, including a DC power supply bus, a processor and/or an electronic storage device. Furthermore, the components 134 may be used to control one or more elements of the DC VCACS 10, including, for example, the evaporator assembly 38 and/or the condenser assembly 34.

[0036] Referring now to Figs. 5 and 6, the evaporator shroud 32, in various embodiments can include condensation collectors 110 for collecting and removing condensation produced by the evaporator heat exchanger 50. Fig. 6 is a blown up view of the section A, shown in Fig. 5, illustrating in detail the condensation collectors 110. In various embodiments, the condensation collectors 110 are small dimples or depressions formed in the evaporator shroud 32 for collecting condensation produced by an evaporator assembly 38. Each condensation collector includes an opening 114.

[0037] The condensation collected in the collectors 110 simply drips out of the collectors 110 via the openings 114. In addition, the condensation remaining in the collectors 110 work to prevent outside external elements, such as water, humidity, salty air, insects, dust, pollen, etc., from infiltrating the evaporator assembly 38. More specifically, the water remaining within the collectors 110 prior to dripping out provide a barrier through which such external elements may not be able to penetrate.

[0038] Additionally, although Figs. 5 and 6 illustrate two condensation collectors 110, it should be understood that there may be more or fewer than two condensation collectors 110 without departing from the scope of this disclosure. Additionally, although the condensation collectors 110 each include the opening 114, one or more of the condensation collectors 110 may not include an opening 114, or may include more than one opening 114 without departing from the scope of this disclosure.

[0039] Although the condensation collectors 110 are formed in the evaporator shroud 32, it should be understood that the condensation collectors 110 could be a separate part positioned on the bottom of the evaporator shroud without departing from the scope of this disclosure.

[0040] The evaporator assembly 38 can include an evaporator air deflector 138, which is mounted above the evaporator heat exchanger 50, as best shown in Fig. 7. The evaporator air deflector deflects air flowing downwardly from the evaporator air mover section 58 away from the evaporator heat exchanger 50. The air deflector 138 may be formed from any suitable metal or plastic. In various embodiments, the air deflector is formed integrally with the evaporator shroud 32.

[0041] In various embodiments, the housing panel 70 includes a terminal block 142 for connecting a direct current power supply to one or more elements of the VCACS 10 including, for example, the evaporator assembly 38 and the condenser assembly 34.