Abstract:
Light sources are mounted within a light-proof enclosure in which photovoltaic panels are mounted to produce electrical power irrespective of weather conditions outside the enclosure.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention generally relates to the generation of electrical power, particularly by using photovoltaic cells to power electrical systems.  
           [0003]    2. Description of the Related Art  
           [0004]    Photovoltaic or solar cells are operative to convert light directly into electricity, and are commonly used on calculators as replacements for batteries. Solar cells are also configured in the form of panels and positioned on a roof of a house to receive the sun&#39;s energy. Such solar-powered residential systems, however, require the correct orientation relative to the sun, different orientations during the day and for different seasons, and storage batteries to store power for subsequent use during the night or on cloudy days.  
         SUMMARY OF THE INVENTION  
       OBJECTS OF THE INVENTION  
         [0005]    Accordingly, it is a general object of this invention to provide electrical power using photovoltaic cells in an environment not subject to weather conditions.  
         FEATURES OF THE INVENTION  
         [0006]    In keeping with the above object and others which will become apparent hereafter, one feature of the present invention resides in an electrical power module that comprises a light-proof enclosure, at least one electrically energized light source and preferably a plurality of light sources mounted within the enclosure for emitting light, and at least one photovoltaic panel and preferably a plurality of photovoltaic panels mounted within the enclosure for converting the light emitted by each source to electrical power.  
           [0007]    In a preferred embodiment, the panels are mounted at interior surfaces of walls of the enclosure. Also, one or more light reflectors are mounted on the walls.  
           [0008]    A control circuit is operative for energizing each light source. The control circuit preferably includes a relay switchable between states in which an external power source, such as a battery, is operatively connected to, or disconnected from, each light source. An inverter is also employed to convert DC voltage supplied by the battery to AC voltage.  
           [0009]    The enclosure, itself, is a closed box. The light sources allow the continuous production of electricity irrespective of weather conditions outside the box.  
           [0010]    The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 is a circuit diagram of an electrical power system employing a power module in accordance with this invention;  
         [0012]    [0012]FIG. 2 is a sectional view taken on line  2 - 2  of FIG. 1;  
         [0013]    [0013]FIG. 3 is a sectional view taken on line  3 - 3  of FIG. 2; and  
         [0014]    [0014]FIG. 4 is a sectional view taken on line  4 - 4  of FIG. 2. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0015]    Reference numeral  10  in FIGS.  1 - 4  generally identifies a light-proof enclosure having front  12  and rear  14  walls, a pair of end walls  16 ,  18 , and top  20  and bottom  22  walls, all of the walls bounding an interior compartment. The walls are opaque.  
         [0016]    At least one lamp  24 , and preferably a plurality of such lamps  24 , is mounted within the compartment. Each lamp is operative, when electrically energized, preferably by an AC voltage, to emit light. High-energy photon lamps, quartz tungsten halogen lamps, fluorescent lamps, light emitting diodes, and flash simulators are examples of the type of lamp that can be employed.  
         [0017]    At least one photovoltaic panel  26 , and preferably a plurality of photovoltaic panels  26 , is mounted on interior surfaces of the enclosure walls. As shown, the panels  26  are mounted on the front, rear and end walls. Each photovoltaic panel  26  is constituted of solar cells made of a semiconductor material such as silicon, which is currently the most commonly used. Basically, when light strikes a solar cell, a certain portion of the light is absorbed within, and transferred to, the semiconductor material. The energy knocks electrons loose, allowing them to flow freely. One or more electrical fields act to force the electrons freed by light absorption to flow in a certain direction. This flow of electrons is a current which is drawn off for external use by conductive contacts on the cell. The process of converting light energy to electrical energy in a solid-state photovoltaic cell is self-contained. There are no moving parts and no materials are consumed or emitted.  
         [0018]    A suitable panel is available from Siemens G.m.b.H. as its Model No. SM110, and is rated for {fraction (12/24)} v operation, 110 w of power, and generates an output voltage of {fraction (17.5/35)} v and an output current of {fraction (6.3/3.15)} amperes, and is rectangular in shape with dimensions of 51.8″×26″. One or more such panels can be mounted on an enclosure wall.  
         [0019]    Referring now to FIG. 1, a control circuit for electrically energizing the lamps  24  includes a relay  30  switchable from the illustrated normally closed contact  32  in an initializing mode of operation, to the normally open contact  34  in a steady state of operation. By way of non-limiting, numerical example, the operation of the power system will be described for a 400 watts system, utilizing a stack of six panels each operative for generating about 80 watts. Two panels are mounted on each of the front and rear walls. One panel is mounted on each end wall. The panels are electrically connected in parallel and produce a total of about 37.8 amperes at about 12 v DC.  
         [0020]    In the initializing mode, a pre-charged battery  36  capable of delivering about 60 ampere-hours at 12 v DC is connected to switch  38  which is manually closed to deliver its current to the normally closed contact  32  and to an inverter  40  operative for converting DC current to AC current. The inverter requires about 33.3 amperes at 12 v DC at its input to produce 3.33 amperes at 120 v AC, or about 400 watts.  
         [0021]    A voltmeter  42  and ammeter  44  at the inverter output verify proper operation, after which switch  46  is closed to deliver the output current to a ballast  48  and, in turn, to each of the lamps  24  within the enclosure  10 .  
         [0022]    The light emitted by the lamps causes the panels to produce electricity and, in this example, about 6.3 amperes per panel for a total of about 37.8 amperes at 12 v DC. A voltmeter  50  and ammeter  52  at the output of the panels verify system operation, after which switch  54  is closed to deliver the output current of the panels to the normally open contact  34  and to one input of a sensor  56 . The other input of the sensor  56  is connected to the inverter output.  
         [0023]    Once the sensor  56  detects power at both of its inputs, the sensor  56  triggers the relay  30  to switch from contact  32  to contact  34 , thereby disconnecting the battery  36  and also transferring the output current from the panels to the inverter  40 . The switch  38  can be opened. An output switch  56  is closed to convey a portion of the output current to a load for electrical power consumption.  
         [0024]    As shown in FIGS.  2 - 3 , six lamps  24  are arranged in the enclosure in a spaced-apart relationship in order to uniformly illuminate the panels. The lamps need not be linear as shown, but can be point sources, or configured in two-dimensional shapes such as a U-shape for increased area coverage. Reflectors  58 ,  60  are mounted within the enclosure, for example, on the interior surfaces of the top and bottom walls, for reflecting the light emitted by the lamps uniformly toward the panels. The reflectors may be flat mirrors, or prisms, or a specular film, such as a metal foil.  
         [0025]    The enclosure is preferably formed with an access door for replacement, maintenance and repair of the lamps and panels therein. The door has seals to prevent light from escaping when the door is closed.  
         [0026]    It will be understood that each of the elements described above, or two or more together, also may find a useful application in other types of constructions differing from the types described above.  
         [0027]    While the invention has been illustrated and described as embodied in an electrical power module and system, is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.  
         [0028]    Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.  
         [0029]    What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.