Passive solar wire screens for buildings

Passive solar wire screens mount vertically on an edifice. The screens have rods vertically arranged parallel to one another and have wires horizontally arranged parallel to one another. The wires attach to the rods and have first surfaces facing away from the edifice in an upward direction from vertical. The wires also have second surfaces facing toward the edifice in a downward direction from vertical. When the sun has a summer elevation on the horizon, the first surfaces passively reflect solar energy incident thereto away from the wire screens. When the sun has a winter elevation on the horizon, however, the first surfaces passively reflect solar energy incident thereto toward the second surfaces, which in turn passively reflect the solar energy toward the edifice. A concave surface on the wires can also reflect thermal energy back to the edifice.

BACKGROUND

Wire screens are used for chemical filtration, architectural accents, and other purposes.FIG. 1shows the typical construction of a prior art wire screen. As shown, the screen has parallel wires12attached by welds16to parallel rods14oriented perpendicularly thereto. The wires12can be V-shaped wires, and the rods14can be cylindrical, square, etc. Both the wires12and rods14are typically made of stainless steel, but they can be made of other materials, including aluminum and copper alloys.

In industrial applications, gaps between the screen's wires12can filter chemical compositions, solids, etc. In architectural applications, the screens can be used on a building as a decorative feature for frontages, overhangs, column covers, floor gratings, ventilation grids, wall partitions, handrails, etc. For example, the Seven World Trade Center in New York and the Guthrie Theater parking garage in Minneapolis have wire screens that cover the exterior. Typically, the architectural design of such wire screens has focused on the reflectivity and orientation of the wire surfaces to enhance appearance.

SUMMARY

Passive solar wire screens mount vertically on an edifice, building, or other structure. The screens have rods vertically arranged parallel to one another and have wires horizontally arranged parallel to one another and attached to the rods. The wires have first surfaces facing away from the edifice in an upward direction and have second surfaces facing toward the edifice in a downward direction. When the sun has a higher summer elevation on the horizon, the first surfaces passively reflect solar energy incident thereto away from the screens, thereby reflecting the solar energy away from the edifice. When the sun has a lower winter elevation on the horizon, however, the first surfaces passively reflect solar energy incident thereto toward the second surfaces, which in turn passively reflect the solar energy toward the edifice. A concave surface on the inner edges of the wires can also reflect thermal energy back to the edifice.

DETAILED DESCRIPTION

A passive wire screen system20schematically illustrated inFIG. 2has a plurality of wire screens50mounted on a building or other edifice25. Although the wire screens50can be used for buildings, they could also be used for non-building applications, such as delivery trucks, rail cars, temporary structures, etc. These wire screens50can be constructed as panels and made of any particular dimensions suitable for their own support and reinforcement, and the screens50can attach to the building25using any conventional technique, such as brackets, frames, and other similar mounting hardware. The wire screens50can be designed with standard dimensions and mounting hardware or may be individually configured for a given implementation.

In the northern hemisphere, the wire screens50are preferably mounted on one or more south-facing walls of the building25(the opposite being the case of a building in the southern hemisphere) so that the wire screens50face the orientation of the sun as it travels across the sky. As oriented, the wire screens50can reflect solar energy away from the building25when the sun has a higher summer elevation30on the horizon and can direct solar energy toward the building25when the sun has a lower winter elevation40. In this way, the wire screens50act as a seasonally reflective exterior surface of the building25that passively reflects solar energy in the summer and passively collects solar energy in the winter to reduce both heating and cooling costs for the building25.

Front and back sides of portion of a wire screen50are shown inFIGS. 3A-3B, respectively. The screen50has a plurality of horizontally arranged wires52positioned parallel to one another on its front face as shown inFIG. 3A. These wires52weld to a plurality of vertically arranged rods54positioned on the screen's back face as shown inFIG. 3B. Many of the same techniques for constructing, arranging, and welding wire screens known in the art can also be used for the wires52and rods54of the disclosed screens50so that specific details are not provided herein. The wires54, however, have an asymmetrical shape to achieve the reflection and collection of solar energy so that fabricating the screen50may require particular attention to precision when attaching the wires54to the rods52.

The wire screens50mounted to the building25are entirely passive and function without moving parts, such as an adjustable louver system, electronic controls, and the like. In this way, the wire screens50can operate passively with the seasonal changes in reflectivity while still functioning as a decorative feature. Lacking a movable louver and control system or the like, the passive wire screens50require less cost for installation and operation, although the disclosed screens50could be constructed with such moving parts if desired.

As noted briefly above, the wires52of the screen50have an asymmetrical shape that is different than the conventional wires used on prior art wire screens. In particular,FIGS. 4A-4Bshow details of one embodiment of wires60for the disclosed wire screen50. In the end view shown, the screen50mounts adjacent an absorption surface55, which could be a wall, window, or other part of an edifice, building, or the like. This surface55could be painted black to absorb incoming radiation. Alternatively, the surface55could be a conventional solar collector placed behind the screen50to enhance collection efficiencies.

As shown, each of the wires60has an acute back edge62, a front reflective face64, and a reflective under surface66. The back edge62welds to the vertically arranged rods54using conventional techniques. As shown, adjacent wires60are attached at a separation from one another on the rods54so that a curved or bent channel56is defined between each adjacent wire60. The front face64extends from a front edge63and faces upwards toward the horizon at an angle θ1from vertical. The under surface66also extends from the front edge63but faces downward towards the surface55at an angle θ2from horizontal. The reflective faces64and surfaces66can be polished or coated to enhance their reflectivity.

The angular orientation θ1of the front face64can be selected to passively reflect solar energy incident thereto away from the surface55in the summer months (when the sun's elevation is high) and to passively reflect the solar energy upwards towards the adjacent wire60in the winter months (when the sun's elevation is low on the horizon). Likewise, the angular orientation θ2of the under surface66can be selected to passively reflect the reflected solar energy incident thereto from the wire60below towards the surface55in the winter months. In this way, the screens50can help maintain the surface55cooler in the summer months and can provide heat energy to the surface55in the winter.

The reflective face64and surface66could be either flat or curved (parabolic) to maximize collection efficiency. In one implementation, the front face64can be flat as shown inFIGS. 4A-4Band can be at the acute angle θ1of approximately 45-degrees from vertical. The under surface66can also be flat as shown and can be at the acute angle θ2of about 15-degrees from horizontal. However, the angles, size, and separation of the wires60may change depending on the latitude of the building or other structure on which they are used and depending on the orientation of the screen50relative to the sun's rays. (The orientations of the sun's rays32/42depicted in the drawings are representative and provided for illustrative purposes.)

As shown inFIG. 4A, the wires' front faces64of the wires60reflect rays32from the sun at the higher summer elevation incident thereto away from the screen50. In this way, the screen50functions as a reflector during summer months when the sun's elevation is high on the horizon so that the energy from the sun's rays32can be reflected away from the surface55.

As shown inFIG. 4B, the wires' front faces64reflect rays42from the sun at the lower winter elevation incident thereto upward toward the angled under surfaces66of adjacent wires60. In turn, the under surfaces66reflect the rays back towards the building's surface55. In this way, the wire screen50functions as a collector of the sun's rays42during winter months when the sun's elevation is lower on the horizon so that the energy from the sun's rays42can be reflected onto the surface55.

InFIGS. 5A-5B, details of another embodiment of wires70for the disclosed wire screen50are illustrated in end views. As before, these wires70have acute back edges72that weld to the rods54of the screen50. In contrast to the previous embodiment, the wires70have concave front faces74and concave under surfaces76that extend from front edges73. As before, adjacent wires70are attached at a separation from one another on the rods54so that the curved or bent channel56is defined between each adjacent wire70.

As shown inFIG. 5A, the concave front faces74reflect rays32from the sun at the high summer elevation incident thereto away from the wires70so the wire screen50functions as a reflector and keeps the sun's energy away from the surface55. As shown inFIG. 5B, the concave front faces74reflect rays42from the sun at the lower winter elevation incident thereto upward toward the concave under surface76of adjacent wires70. In turn, the concave under surfaces76reflect the solar rays back towards the building's surface55so the wire screen50functions as a collector.

As noted previously, adjacent wires60/70are attached at a separation from one another on the rods54so that the curved or bent channel56defined between each adjacent wire60/70allows the reflected rays42to reach the surface55. Each wire60/70has surfaces68/78above and below the back edge62/72that are oriented to create this channel56. These surfaces68/78may also be capable of reflecting at least some of the thermal energy emanating from the surface55back to the surface55.

InFIG. 6, details of another arrangement of wires80for the disclosed wire screen50is illustrated in an end view. As before, these wires80have back edges82that weld to the rods54of the screen50. In addition, the wires80have front faces84and under surfaces86that extend from front edges83. These faces84and surface86can be curved as shown or can be angled as discussed previously. As before, the adjacent wires80are attached at a separation from one another on the rods54so that a channel56is defined between each adjacent wire80.

When the sun is at the high summer elevation, the front faces84can reflect summer rays32incident thereto away from the wires80so the wire screen50functions as a reflector and keeps the sun's energy away from the surface55. When the sun is at the lower winter elevation, the front faces84can reflect winter rays42incident thereto upward toward the under surface86of adjacent wires80. In turn, the under surfaces86can reflect the solar rays back towards the building's surface55so the wire screen50functions as a collector. As further shown, the wires80can be separated by a predetermined distance D so that at least some winter rays43can pass between the adjacent wires80and reflect directly onto the building's surface55to provide heating benefits.

Depending on the separation D of the wires80and the elevation of the sun relative to the screen50, such directly passed rays43may occur in addition to and/or as an alternative to reflecting the rays42from the faces84, to the surfaces86, and to the building's surface55. At certain times in the winter, for example, the wires80can allow for direct passage of some winter rays43between the wires80without reflection on the face84and under surfaces86when these rays43have a particular angular orientation to the screen50. At other times during the winter, however, the wires' faces84and surfaces86can be designed to either reflect or not reflect the rays42to the building surface55that are incident to the wires' front faces84.

FIG. 7shows an end view of portion of a wire screen having yet another embodiment of wire90. Again, these wires90have rear edges92that weld to the rods54of the screen50and have front faces94and under surfaces96. As before, adjacent wires90are attached at a separation from one another on the rod54with a curved or bent channel56defined between each adjacent wire90. As opposed to other embodiments, these wires90also have concave or bent back surfaces88facing the surface55and intended to reflect thermal radiation44from the surface55back towards it. This reflection may reduce heat loss from the building's surface55during the night, for example.

The foregoing description of preferred and other embodiments is not intended to limit or restrict the scope or applicability of the inventive concepts conceived of by the Applicants. In exchange for disclosing the inventive concepts contained herein, the Applicants desire all patent rights afforded by the appended claims. Therefore, it is intended that the appended claims include all modifications and alterations to the full extent that they come within the scope of the following claims or the equivalents thereof.