Abstract:
A radiant-reflective shield for an air conditioner condenser unit has slatted or louvered sidewalls and a partial top cover. The partial top cover shades sunlight from impinging on all or most of the top surface of the condenser unit without obstructing exhaust air exiting from the unit.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention relates to a shield for a condensing coil unit of a central air conditioner to improve operating efficiency and minimize the amount of radiant energy striking said unit. Many outdoor central air conditioner condensing coil units are exposed to intense heat from direct sunlight. Such radiant heating causes the unit to consume more electrical energy to power a fan to effect desired cooling of the condensing coil. 
         [0003]    2. Description of the Prior Art 
         [0004]    U.S. Pat. No. 5,226,264 shows a portable shelter for an air conditioner unit that has an inclined roof and three side walls. The shelter is mounted to a frame with wheels. It may be rolled into position to surround the metal housing of an outside air conditioner unit. The inclined roof extends over the entire top of the air conditioner unit to preclude debris from contracting the unit. The shelter also reflects sunlight to prevent radiant heat from building up on the air conditioner unit. 
         [0005]    U.S. Pat. No. 4,615,181 illustrates a cover for an air conditioner with louvers on the top and sidewalls. The cover may be three-sided. The slats or louvers across the top may be adjusted at an angle to better reflect sunlight away from the air conditioner. The slats extend over the entire top of the air conditioner unit. This patent also proposes dripping water onto the slats on the sidewalls to help cool the intake air. 
         [0006]    U.S. Pat. No. 4,953,328 shows yet another cover for an air conditioning compressor unit with slats or louvers. The &#39;328 patent refers to pivotal shutters over each of the sidewalls and top ceiling, where each shutter is selectively movable between open and closed positions. The top ceiling extends to cover the entire air conditioning condenser unit. 
         [0007]    U.S. Pat. No. 3,011,424 shows a louvered air conditioner cover intended for a window air conditioning unit. The cover has a solid upper roof and louvered sides, and can be installed over a window-mounted air conditioner unit. 
         [0008]    Other radiant shields and covers for air conditioning condenser units are shown in U.S. Pat. Nos. 6,158,175, 6,430,954; 6,595,017; 4,730,423; and 6,138,993. 
         [0009]    The background art shields generally cover the entire roof of the air conditioner condenser unit, either with a solid roof section or with a screen or shuttered section. In all of these prior designs, the air exhaust from the air conditioner condenser unit is hampered to some degree. This limits cooling efficiency by holding hot air from the exhaust close to the condenser unit, rather than expelling it away. Accordingly, a shield for an air conditioner condenser coil unit that reflects radiant energy without adversely impacting air flow to and out of the condenser coil unit is still sought. 
       SUMMARY OF INVENTION 
       [0010]    A radiant-reflective shield for an air conditioner condenser unit has sidewalls with slatted openings to permit air flow therethrough so that air may reach the air condenser unit and a top cover to shield at least a portion of radiant energy from impinging upon the air conditioner condenser unit without obstructing exhaust air from exiting the air conditioner condenser unit. In one embodiment, the top cover extends over ¼ to ⅓ of the top surface of the air conditioner condenser unit. The shield deflect radiant energy sufficiently to reduce monthly household or building energy costs, preferably reducing such costs by at least 10% from costs incurred in a comparable calendar month without such shield. 
         [0011]    The top cover may be fixedly mounted to the top frame. Alternatively, the top cover may be movably mounted to the top frame, such that the top cover may be moved from a first position to a second position to shield the air conditioner condenser unit from impingement by radiant energy. In yet another embodiment, the top cover may have a slanted top surface. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a perspective view of a shield of the invention; 
           [0013]      FIG. 2  is a front elevational view of the shield of  FIG. 1 , with an upper portion partially broken away; 
           [0014]      FIG. 3  is a top plan view of the shield of  FIG. 1 ; 
           [0015]      FIG. 4  is a cross-sectional view in elevation taken along line  4 - 4  of  FIG. 3 ; and 
           [0016]      FIG. 5  is a partial left side elevational view of an alternative shield of the invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0017]    Referring first to  FIGS. 1-4 , a shield  10  for an air conditioner condenser coil unit  30  (said unit shown in phantom outline in  FIG. 1 ) has three sidewalls formed from slatted side panels  16 ,  18 ,  20 . Each slatted side panel  16 ,  18 ,  20  has a series of louvers  22  that permit air to flow therethrough to reach air conditioner condenser unit  30 . The air flows through the louvers  22  in the direction of arrows  24 . 
         [0018]    The louvers  22 , may be formed to have a predetermined or set opening angle. Alternatively, the slats of the louvers  22  may be rotatable or adjustable to permit varying the extent of the slatted openings in the side panels  16 ,  18 ,  20 . Such openings may vary from 180° (parallel and fully open) to 45° (as shown in  FIG. 4 ) to any other desired angle. Such slats or louvers  22  block radiant energy, such as sunlight, from impacting or substantially impacting upon air conditioner condenser unit  30  In this manner, the slats or louvers  22  prevent or substantially prevent radiant heating of air conditioner condenser unit  30  without impacting or substantially impacting the flow of intake air to the unit  30 . 
         [0019]    The side panels  16 ,  18 ,  20  form three sidewalls of the shield  10 . Top and bottom portions of the side panels are fastened to a frame formed with frame members  12 ,  14 . Fastening may be with screws or bolts or other customary fasteners  28 . As shown In  FIGS. 1 and 4 , screws with decorative screw heads may be installed to fasten panels  16 ,  18 ,  20  to frame members  12 ,  14 . 
         [0020]    In the embodiment shown in  FIGS. 1-4 , top cover  26  is movably mounted to the top of the shield  10 . Top cover  26  is shown in  FIGS. 1-4  having a length and width that extends to cover only a minor portion of the top surface of the exhaust hood of air conditioner condenser unit  30 , but to an extent sufficient to shield the air conditioner condenser unit  30  from sunlight or radiant energy impacting upon all or a substantial portion of the unit  30 . The top cover  26  in  FIGS. 1 and 4  is shown adjacent to front panel  18  and extending over about one-quarter to one-third of the unit  30 . In this position, top cover  26  shields the air conditioner condenser coil from radiant energy, but does not block or obstruct exhaust air from exiting the condenser unit  30 . Arrows  32  illustrate that exhaust air has a free path to exit from the shield  10  without having to flow through a screen or other obstruction. 
         [0021]    In some cases, it would also be possible to configure top cover  26  such that it does not cover any portion of the top surface of the air conditioner condenser unit, yet still reflects away all or a major portion of radiant heat from sunlight. For example, top cover  26  could be slanted at an angle or could have an angular or wedge shape. 
         [0022]    In some cases, it would also be possible to configure top cover  26  such that it covers more than one-third of the top surface of air conditioner condenser unit  30 . Preferably, the top cover  26  does not unduly obstruct exhaust air from exiting from the air conditioner condenser unit  30 . 
         [0023]    Referring to  FIGS. 2 and 4 , top frame members  36  each include a slot  38  to receive the ends of shafts  40  on which rollers or wheels  42  are mounted. Said rollers or wheels  42  traverse in contact with frame members  36 . The top cover  26  is mounted to said wheels  42  and shafts  40  via bearing blocks  44 . Accordingly, top cover  26  may be moved in the direction of arrow  46  ( FIG. 1 ) from a first position close to the front side panel  18  to a second position to cover a different portion of the air conditioner condenser unit  30 . The wheels  42  permit the top cover  26  to be moved variously from one position to another position over the air conditioner condenser unit  30 . Thus, the cover  26  may be variously moved to shield any portion or all or substantially all of the air conditioner condenser unit  30  from radiant energy. Preferably, movement of the top cover  26  does not unduly obstruct the exhaust air from exiting the unit  30 . 
         [0024]    Referring next to  FIG. 5 , a top cover  26   a  is shown fixedly mounted to top surfaces of side panels  16 ,  18  and  20 . As such, top cover  26   a  has a width dimension that extends to cover none or only a minor portion of the top surface of the exhaust hood of air conditioner condenser unit  30 . The fixed position is selected so as to minimize obstructions of exhaust air while still providing sufficient shading to reflect radiant heat away from air conditioner condenser unit. In  FIG. 5 , the cover  26   a  extends over about one-quarter to one-third of the top surface of unit  30 . 
         [0025]    The side panels and the top cover may be formed from various weather- and heat-durable materials, such as, but not limited to, aluminum, coated aluminum, other coated metal, certain durable plastics such as polypropylene, polycarbonate, vinyl, and vinyl coated fiberglass or from a solar screen. 
         [0026]    Installing the radiant-reflective shield according to the invention over an air conditioner condenser unit results in energy cost savings of at least about 10% and up to about 30% per month. In some cases where the air conditioner condenser unit is in direct sunlight in a generally western or southern exposed side of a home, energy cost savings may reach about 50% per month. For example, a home residence in a middle Atlantic state in the United States that had an air conditioner condenser coil unit mounted on a slab outside the home had the following energy consumption: 
         [0000]                                                                                                      July 2005   July 2006                       Ave. temp.   77° F.   77° F.           kWh   1820   1584                Percent reduced energy consumed   13%                                August 2005   August 2006                       Ave. temp.   78° F.   79° F.           kWh   1817   1342                Percent reduced energy consumed   26%                        
In July 2006, a shield according to the invention was installed over the air conditioner condenser unit. Between 2005 and 2006, there were no changes in the number of occupants or the energy consumption appliances within the home. The shield reduced energy consumed during when compared with the same month the prior year, wherein the average daily temperature was the same or nearly the same.
 
         [0027]    The invention has been illustrated by detailed description and examples of the preferred embodiments. Various changes in form and detail will be within the skill of persons skilled in the art. Therefore, the invention must be measured by the claims and not by the description of the examples or the preferred embodiments.