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CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit under 35 U.S.C. §119(e) of the earlier filing dates of U.S. Provisional Patent Application No. 62/215,383 filed on Sep. 8, 2016. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of Invention 
         [0003]    This invention relates to an exterior panelized window wall system with integrated solar energy units. 
         [0004]    2. Background of the Invention 
         [0005]    An exterior window wall system is formed by joining panels side-by-side and supporting them with continuous horizontal track members anchored to surfaces above a floor slab (i.e., a sill or base track) and horizontal track members anchored under a floor slab of the floor above (i.e., a ceiling track). Some major functions of an exterior window wall system are to prevent water infiltration, prevent interior water condensation, absorb wind load, and absorb seismic load. In a conventional window wall system, there are many technical problems associated with the above performance functions due to inevitable construction tolerance problems and the requirement of an exterior sealing envelope. 
         [0006]    There currently are no commercially available solar energy systems for out-hanging on or integrating in a window wall system. For a solar energy system with solar energy units either out-hanging on or integrated into a window wall, the need for wiring penetrating the exterior sealing envelope presents technical challenges. In addition, a major problem with integrating a solar energy unit into a window wall is the difficulty and expense required to replace a dysfunctional or damaged solar energy unit. An economical solution for an integrated solar energy window wall is highly desirable. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    Some objectives of preferred integrated solar energy window wall systems of the present invention include fulfilling the following functional performances: (1) Integrating any commercially available solar energy unit into a panelized window wall system without affecting other performance functions such as aesthetic features, water-tightness, and structural safety. (2) Permitting easy replacement of an individual solar energy unit from the building interior. (3) Providing inter-floor electrical wiring connections without drilling a hole through the floor slab. 
         [0008]    In preferred embodiments of the present invention, a solar energy unit is integrated into an airloop window wall panel by using the solar energy unit as the panel facing element. U.S. Pat. No. 8,001,738, which is incorporated by reference, describes the application of the pressure equalized airloop principle to a window wall system. 
         [0009]    In preferred embodiments, multiple window wall panels having integrated solar energy units are used in a window wall. The solar energy units are electrically connected to each other using inter-panel wires that may pass through holes in the head frame members of the window wall panels and/or through air spaces in the panel frames and panel joints. An inter-floor electrical connection may be made with a wiring path over the outside edge of a floor slab. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a typical partial elevation of an airloop solar energy window wall system of a preferred embodiment. 
           [0011]      FIG. 2  is an isometric back view of a shop-assembled and ready to be erected airloop solar energy window wall panel of a preferred embodiment with an insulated glass solar energy unit. 
           [0012]      FIG. 3  is an isometric back view of a shop-assembled and ready to be erected airloop solar energy window wall panel of a preferred embodiment with a single glass solar energy unit. 
           [0013]      FIG. 4  is a fragmental cross-section taken along line  4 - 4  of  FIG. 1 , showing an upper wall panel with an integrated glass solar energy unit, a lower wall panel with an insulated glass solar energy unit, and a concrete floor slab in between, and a preferred wiring path for an inter-floor electrical connection between solar energy units. 
           [0014]      FIG. 5  is a fragmental cross-section taken along line  5 - 5  of  FIG. 1 , showing the vertical joint between adjacent window wall panels and showing the utilization of a vertical airloop space as a vertical wiring channel. 
           [0015]      FIG. 6  is an exploded, isometric back view looking downwardly at the head frame members of two adjacent window wall panels, illustrating a preferred inter-panel wiring path. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. For the purpose of clarity, in the following descriptions, the required protective sleeves for electrical wiring at the hole locations on the aluminum extrusions are not shown in the drawings. 
         [0017]      FIG. 1  is a typical partial elevation of an airloop solar energy window wall system  10  of a preferred embodiment with side by side panels  11   c,    11   d,    11   e,    11   f  spanning between two adjacent floors  12  and  13 . Side-by-side panels  11   a,    11   b  span between floor  12  and the floor above. The floor slab edges are aesthetically covered by cover plates  14   a,    14   b,    14   c ,  14   d.    
         [0018]      FIG. 2  is an isometric back view (looking upwardly on the underside of the head frame member  21 ) of a shop-assembled and ready to be erected airloop solar energy window wall panel  11  of a preferred embodiment having an insulated glass solar energy unit  22 . 
         [0019]    The insulated glass solar energy unit  22  may be any commercially-available insulated glass solar energy unit and has an interior glass pane and an exterior glass pane. A wire chase is sandwiched between the glass panes and has a positive outlet wire with a shop-installed positive connector  23  and a negative outlet wire with a shop-installed negative connector  24 . 
         [0020]    The insulated glass solar energy unit  22  is secured in an airloop panel perimeter frame. The shop-assembled airloop panel perimeter frame has a head frame member  21 , two jamb frame members  27   a,    27   b,  and a sill frame member  20 . The solar energy unit  22  is structurally secured inside the panel frame on three sides (sill and two side jambs) by demountable glazing beads  18   a,    18   b,    18   c.  A glazing bead for the head frame member is added during panel erection, as described below in the description accompanying  FIGS. 4 and 6 . Two wiring holes  25   a,    25   b  are provided on the head frame member  21 . 
         [0021]    As one of ordinary skill in the art would recognize as described in U.S. Pat. No. 8,001,738, an assembled airloop panel has air spaces substantially forming a loop around and near the panel facing element (e.g., a solar energy unit) and generally within the panel perimeter frame. The airloops are connected to exterior air to provide pressure equalization that prevents water infiltration. Additional pressure-equalized spaces are formed in the joints between adjacent panels, as shown in  FIG. 5 . 
         [0022]    In a preferred embodiment, one of the electrical connectors  23  of the solar energy unit  22  is shop-connected to an inter-panel wire  28 . The inter-panel wire  28  is threaded through a wiring hole  25   a  to the exterior side of the head frame member  21 . The loose end  26  of the inter-panel wire  28  hangs outside of the jamb frame member  27  for connection to a solar energy unit in a different wall panel (e.g., a wall panel next to, above, or below the wall panel  11 ) upon installation. The wiring hole  25   b  on the other side of the head frame member  21  is provided for guiding the inter-panel wire of an adjacent panel to make a field connection to the electrical connector  24 . The length of the inter-panel wire depends on the distance required to make the inter-panel connection. 
         [0023]      FIG. 3  shows an isometric back view of a shop-assembled and ready to be erected airloop solar energy window wall panel  111  of a preferred embodiment having a single glass solar energy unit  122  with a structural back-up panel  130 . For illustration purposes, a portion of the structural panel  130  is cut away in  FIG. 3  to show a portion of the solar energy unit  122 . The single glass solar energy unit  122  may be a commercially-available single glass solar energy unit. The single glass solar energy unit  122  has a wire chase  138 , a positive outlet wire with a shop-installed positive connector  123  and a negative outlet wire with a shop-installed negative connector  124 . The electrical connectors  123 ,  124  may be made as integral parts of the wire chase  138 , eliminating the outlet wires. 
         [0024]    For adaptation of the single glass solar energy unit  122  into the present invention, spaced apart structural spacer blocks  134  having the same depth of the wire chase  138  are included around the perimeter of the glass pane of the single glass solar energy unit. The structural spacer blocks  134  may be shop-glued to glass pane. The required number of spacer blocks  134  depends on the size of the glass pane. For purposes of clarity, only two spacer blocks  134  are shown in  FIG. 3 . The structural panel  130  is placed behind the solar energy unit  122 , against the spacer blocks  134  and wire chase  138 . The solar energy unit  122  and the structural panel  130  are structurally secured inside the panel frame on three sides (sill and two side jambs) by demountable glazing beads  118   a,    118   b,    118   c.    
         [0025]    As with the embodiment shown in  FIG. 2 , one of the electrical connectors  123  of the solar energy unit  122  is shop connected to an inter-panel wire  128 , which is threaded through a wiring hole  125   a  to the exterior side of the head frame member  121 . The loose end  126  of the inter-panel wire  128  hangs outside of the jamb frame member  127  for connection to a solar energy unit in a different wall panel (e.g., a wall panel next to, above, or below the wall panel  111 ) upon installation. A wiring hole  125   b  is provided on the other side of the head frame member for guiding the inter-panel wire of an adjacent panel to make a field connection to the electrical connector  124 . The length of the inter-panel wire depends on the distance required to make the inter-panel or inter-floor connection. 
         [0026]      FIG. 4  shows a fragmental cross-section taken along line  4 - 4  of  FIG. 1 , showing an upper wall panel  11   b,  a lower wall panel  11   e , with a concrete floor slab  40  in between. In this preferred embodiment, each of the upper wall panel  11   b  and the lower wall panel  11   e  has an integrated, insulated glass solar energy unit. The sill frame member  54  of the upper wall panel  11   b  is engaged with a base positioning track  35 , which is secured to the top of the concrete floor slab  40  via a base anchoring track  34 . The head frame member  51  of the lower wall panel  11   e  is engaged with a ceiling positioning track  32 , which is secured to the underside of the concrete floor slab  40  via a ceiling anchoring track  39 . 
         [0027]    Based on the airloop window wall system technology described in U.S. Pat. No. 8,001,738, the space  31  between the ceiling positioning track  32  and the head frame member  51  is the top leg of an outer airloop. This space  31  may be used as a horizontal wiring channel for wire connecting solar energy units of adjacent wall panels (see  FIG. 6  for details). The space  33  between the base anchoring track  34  and the base positioning track  35  also may be used as a horizontal wiring channel. 
         [0028]      FIG. 4  also shows a preferred wiring path for an inter-floor electrical connection between the solar energy units of wall panels  11   b,    11   e.  For inter-floor wire connections, a preferred wiring procedure for connecting the solar energy unit in wall panel  11   b  to the solar energy unit in wall panel  11   e  includes the following steps: (1) At a selected location, guide an inter floor wire  58  through the dry vertical segment  41  (shown in  FIG. 5 ) of the outer airloop and penetrate through the base positioning track  35  into the interior wiring channel  33 ; (2) Guide the wire  58  horizontally inside the wiring channel  33  to a selected location and penetrate through the base anchoring track  34  to go outside of the floor slab edge; (3) Guide the wire  58  down over the floor slab edge and penetrate through the ceiling positioning track  32  of the panel below to reach the wiring channel  31 ; (4) Guide the wire  58  horizontally in the wiring channel  31  to a selected location and guide the wire  58  through a wiring hole  55  provided in the head frame member  51  into the interior side of panel  11   e ; (5) Field-install the connector  29  and connect it to the connector of the solar energy unit in panel  11   e ; (6) From the building exterior, roll down the slab edge membrane  36  and install the slab edge cover  14   a;  (7) From the building interior, snap on the interior base cover  37  and install the head glazing bead  38 . 
         [0029]    The above wiring procedures may be easily completed in open spaces before steps (6) and (7). Even though the wiring penetrations in steps (1) and (2) are between the pressure equalized airloop space ( 41  or  31 ) and the interior air space  33 , they are within the dry segment of the outer airloop; therefore, the wiring penetrations will not cause water leakage. The wiring penetrations in steps (3) and (4) are between pressure-equalized airloop spaces; therefore, they will not cause water leakage. 
         [0030]      FIG. 5  shows a fragmental cross-section taken along line  5 - 5  of  FIG. 1 , showing the vertical joint between adjacent window wall panels  11   d,    11   e.  The vertical joint between side-by-side window wall panels  11   d,    11   e  is formed with a vertical joint member  45  in between and engaged with wall panel  11   d  and wall panel  11   e . The vertical joint is formed during installation of the wall panels  11   d,    11   e  and vertical joint member  45  in the manner described in U.S. Pat. No. 8,001,738. 
         [0031]    To summarize a preferred installation procedure, after installation of base and ceiling positioning tracks and anchoring tracks (as shown in  FIG. 4 ), a window wall panel is erected from the building interior by engagement of the sill frame member with the base positioning track and engagement with the head frame member with the ceiling positioning track. To install an adjacent window wall panel, a vertical joint member is engaged with the jamb frame member of the already-erected window wall panel. Next, the top of the panel to be erected from the building interior is tilted inwardly and slightly away from the vertical joint member. The panel to be erected is then dropped into bottom engagement with the base positioning track. Due to the dead weight moment, the top of the panel will swing outwardly and cause contact with the ceiling track. The panel can then be slid laterally to cause panel jamb engagement with the vertical joint member. Panel jamb engagement with the vertical joint member forms vertical airloop spaces (such as the vertical airloop space  41  shown in  FIG. 5 ) between the panel jamb frame member and the vertical joint member. 
         [0032]      FIG. 5  shows the utilization of the vertical airloop space  41  as a vertical wiring channel for an inter-floor wire  58  to provide an electrical connection between solar energy units in wall panels on different floors. The vertical airloop space is formed between the jamb frame member of the panel  11   d  and the vertical joint member  45  when the jamb frame member is engaged with the vertical joint member during panel erection. The wiring channel  41  is behind the water seal line  42 ; therefore, the wiring path is within the dry segment of the outer airloop (see U.S. Pat. No. 8,001,738). During panel erection as described above, the wiring of the vertical segment of wire  58  may be performed with open channel access using either of the following two options: (1) Erecting right panel  11   e , engaging vertical joint member  45  with the erected panel  11   e , inserting wire  58  in space  41 , then engaging of the left panel  11   d  to vertical joint member  45 ; or (2) erecting left panel  11   d,  inserting wire  58  in space  41 , engaging vertical joint member  45  to left panel  11   d,  and engaging right panel  11   e  to vertical joint member  45 . 
         [0033]      FIG. 6  shows an exploded, isometric back view looking downwardly at the head frame members of two adjacent panels  211  and  311  to illustrate a preferred procedure for making an inter-panel wiring connection between side-by-side panels during panel erection. In order to show the wiring path and connection procedures clearly, the panels  211 ,  311  and the vertical joint member  245  are shown in an exploded view before the erection engagement. Right panel  211  is erected first with loose inter-panel wire  228  shop connected to the electrical connector  223  (as shown in  FIG. 2  or  FIG. 3 ). Left panel  311  is the next panel to be erected with an unconnected electrical connector  324  (as shown in  FIG. 2  or  FIG. 3 ). The preferred panel erection and inter-panel wiring procedures for left panel  311  are explained as follows from the building interior: (1) Engage the bottom of the left panel  311  to the base positioning track (shown in  FIG. 4 ) at a location laterally away from the erected right panel  211  and tilt the top of panel  311  slightly inwardly to expose the wire hole  311  (as shown in  FIG. 2 or 3 ) in the head frame member of panel  311 . (2) Guide the loose end of the inter-panel wire  228  from the right panel  211  through the wire hole in the head frame of the left panel  311  into the interior side of the left panel  311 . (3) Engage the vertical joint member  245  into position with the jamb frame member of the erected right panel  211 . (4) Slide the left panel laterally towards the vertical joint member  245  and the right panel  211  and engage the jamb frame member of the left panel  311  with the vertical joint member  245 . (5) Cut off any excess length of the inter-panel wire  228  and field-install the wire connector  329 . (6) Connect the wire connector  329  of the inter-panel wire  228  to the wire connector  324  of the solar energy unit in the left panel  311  to complete the electrical connection between the solar energy unit in the right panel  211  and the solar energy unit in the left panel  311 . (7) Install head glazing beads to the head frame members of the panels  211 ,  311  to complete the air seal around the panel perimeter frames and to conceal the wiring systems in panels  211 ,  311 . The head glazing beads preferably have notches at the locations of wires and wire connectors to allow wires to pass through and/or to accommodate space taken up by wire connectors. Steps 5, 6, and 7 may be executed separately during the wall erection or after the completion of the wall erection. When the wall panels  211 ,  311  are erected, the horizontal path of the inter-panel wire  228  is through the outer airloop spaces (corresponding to airloop space  31  in  FIG. 4 ) formed between the ceiling positioning track and each of the head frame members of the panels  211 ,  311 . 
         [0034]    Solar energy units may be replaced if damaged or dysfunctional, to upgrade to new solar energy technology, or for any other reason replacement is desired. Preferred embodiments of the present invention allow for easy replacement of solar energy units from the interior side of the building. With reference to the preferred embodiment wall panel  11  of  FIG. 2 , replacement of an insulated glass solar energy unit  22  may be accomplished by the following preferred steps: (1) Deglaze the panel  11  by removing the glazing beads on all four sides of the solar energy unit  22 . (2) Disconnect both connectors of the solar energy unit  22  from the respective inter-panel wire connectors and remove solar energy unit  22  from the panel frame. (3) Place a new solar energy unit into the panel frame and re-connect the wire connectors (no need to field-install the connectors on the inter-panel wires because they are already in place). (4) Reinstall the glazing beads on all four sides of the new solar energy unit to secure the new solar energy unit to the panel frame. 
         [0035]    With reference to the preferred embodiment wall panel  111  of  FIG. 3 , the preferred procedure for replacing a single glass solar energy unit  122  are similar to the above steps, except the above steps (2) and (3) involve additional removal and replacement of the structural panel  130 , which may be reused. 
         [0036]    Even though a typical airloop window wall unit is used in illustrating the present invention, some of the design features can be used in other conventional systems to improve their functional performance. 
         [0037]    Nothing in the above description is meant to limit the present invention to any specific materials, geometry, or orientation of elements. Many modifications are contemplated within the scope of the present invention and will be apparent to those skilled in the art. The embodiments described herein were presented by way of example only and should not be used to limit the scope of the invention. 
         [0038]    For example, different panel systems and solar energy units may be used with the present invention. Use of different panel systems or solar energy units may require dimensional changes for panel glazing beads. The same panel joint design can be used for different panel systems. Therefore, different panel systems can be easily erected side-by-side in any combination.

Summary:
An airloop window wall system with solar energy units integrated into the window wall panels is disclosed. The disclosed system provides electrical connections between adjacent solar energy window wall panels without compromising the window wall watertightness performance and permits easy replacement of solar energy units from the building interior.