Abstract:
A photovoltaics teaching aid. The present device is adapted to serve as a teaching aid in order to assist individuals in learning the principles behind photovoltaics, in order to better promote science, technology, engineering, and mathematics (STEM) education. The present invention is a transportable cart including an angled, adjustable array of solar panels, a rechargeable battery, and a solar water heating system. The present invention further includes a number of different devices that are removably attached to the cart to assist individuals in making necessary measurements for calculations, including a multimeter and an angle gauge. Furthermore, a bus is provided that allows individuals to alternatively connect the panels of the solar array in series or in parallel. By changing the manner by which the panels are connected, individuals can study the different resulting effects on the other electrical components.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/948,803 filed on Mar. 6, 2014. The above identified patent application is herein incorporated by reference in its entirety to provide continuity of disclosure. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to photovoltaics and teaching aids. More specifically, the present invention relates to devices adapted to assist in teaching students the principles of photovoltaics by providing them with a convenient means to measure power generated by solar panels and the real world applications thereof. Additionally, the present invention is adapted to serve as a backup generator in emergency situations. 
       BACKGROUND OF THE INVENTION 
       [0003]    Science, technology, engineering, and mathematics (STEM) education has increasingly become a cornerstone of students&#39; educations because of its importance in an increasingly technologically-dependent society. Furthermore, it is critical to educate students as to renewable sources of energy to encourage the next generations of STEM students to pursue these avenues of research. Access to hands-on activities and demonstrations generally increases the effectiveness of teachers&#39; lesson plans; however, currently available photovoltaic devices are not adequate for serving as teaching aids because they do not allow individuals to monitor to the output of the solar panels, they are not adapted to allow users to easily adjust variables associated with the operation of the devices in order to test hypotheses, they are not generally transportable, and they lack the ability to provide users with the ability to visualize tangible, immediate effects of photovoltaics. Therefore, there is a need in the prior art for a teaching aid for photovoltaic concepts that provides all of the aforementioned benefits. 
       SUMMARY OF THE INVENTION 
       [0004]    In view of the foregoing disadvantages inherent in the known types of photovoltaic devices now present in the prior art, the present invention provides a photovoltaics teaching aid wherein the same can be utilized for providing convenience for the user when teaching students about clean energy. The present device is adapted to serve as a teaching aid in order to assist individuals in learning the principles behind photovoltaics, in order to better promote science, technology, engineering, and mathematics (STEM) education. The present invention comprises a transportable cart, an array of solar cells adjustably attached to the cart, a rechargeable battery, and a solar water heating system. The present invention further includes a number of different devices that are removably attached to the cart to assist individuals in making necessary measurements for calculations, including a multimeter and an angle gauge. Furthermore, a bus is provided that allows individuals to alternatively connect the panels of the solar array in series or in parallel. By changing the manner by which the panels are connected, individuals can study the different resulting effects on the other electrical components. 
     
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
         [0005]    Although the characteristic features of this invention will be particularly pointed out in the claims, the invention itself and manner in which it may be made and used may be better understood after a review of the following description, taken in connection with the accompanying drawings wherein like numeral annotations are provided throughout. 
           [0006]      FIG. 1  shows a perspective view of the present invention. 
           [0007]      FIG. 2  shows a perspective view of the control panel of the present invention. 
           [0008]      FIG. 3  shows a perspective view of the present invention with the solar panels removed therefrom, exposing the solar water heating panel disposed thereunder. 
           [0009]      FIG. 4  shows a schematic diagram of the water heating system of the present invention. 
           [0010]      FIG. 5  shows a block diagram of the electrical components of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0011]    Reference is made herein to the attached drawings. Like reference numerals are used throughout the drawings to depict like or similar elements of the photovoltaics teaching aid. For the purposes of presenting a brief and clear description of the present invention, the preferred embodiment will be discussed as used for teaching the students about clean energy. The figures are intended for representative purposes only and should not be considered to be limiting in any respect. 
         [0012]    The present invention is a compact, portable device for use in assisting in teaching students the concepts, processes, and applications of photovoltaics, especially with regards to STEM education. The present invention is adapted to serve as a modular, adaptable device that can be used in many different ways to illustrate the principles and real-world applications of photovoltaics. The present invention comprises two separate systems demonstrating two separate applications of photovoltaics to the field of clean energy. The first system comprises a photovoltaic array that charges a battery disposed on the device and a number of different instruments that can be used in conjunction with this system to perform experiments with the charging of the battery. The second system comprises a solar water heating system that heats a volume of water held within a reservoir disposed on the cart that can be used to demonstrate to students the practicality and benefits of such heating systems. 
         [0013]    Referring now to  FIG. 1 , there is shown a perspective view of the present invention. The present invention comprises a cart  11  having a plurality of wheels  14  disposed on the undersurface thereof, a control panel  31 , a support surface  12  with a photovoltaic array comprising one or more solar panels  13  disposed thereon, a storage area  21  disposed beneath the support surface  12 , and a rechargeable battery  15 . The support surface  12  is attached to the cart  11  via a pivotable connection  18  at a first end and via a slidable connection  19  at a second end thereof. The depicted embodiment of the present invention comprises four solar panels  13 ; however, no claim is made as to the number of solar panels  13  utilized by the present invention. The pivotable connection  18  allows uses to adjust the angle of the support surface  12  in order to, for example, compensate for the position of the sun in the sky and maximize the amount of solar energy to which the solar panels  13  are exposed. In the one embodiment of the present invention, the slidable connection  19  further comprises a locking mechanism adapted to hold the support surface  12  securely in place. In the depicted embodiment of the present invention, the locking mechanism comprises fasteners  22  with a nut. When the user wishes to adjust the position of the support surface  12 , the user can loosen the fasteners  22 , raise or lower the support surface to the desired angle, and then re-tightened the fasteners  22  to hold the support surface  12  at the desired angle. However, no claim is made as to the specific type of locking mechanism utilized by the present invention. The solar panels  13  comprise conventional solar panels as are known in the prior art. 
         [0014]    The solar panels  13  are connected to the various other electrical components of the present invention via a bus  20 . The solar panels  13  are in turn removably connected to the bus  20  via electrical connectors, such as banana clips. The solar panels  13  can be connected either in parallel or in series by altering the manner in which the solar panels&#39;  13  electrical connectors are connected to the bus  20 . This allows students to test the differences between electrical circuitry connected in series or in parallel and run experiments using circuits of these different configurations. 
         [0015]    The solar panels  13  are in electrical communication, through the bus  20 , with at least one rechargeable battery  15  disposed on the cart  11 . As with conventional photovoltaic arrays, the solar panels  13  convert solar energy to DC electricity, which is then stored for later use by the battery  15 . In one embodiment of the present invention, the solar panels  13  are electrically coupled to an inverter, which is then in turn electrically coupled to the battery  15 . In one embodiment, the inverter comprises a solar inverter, which compensates for the variable magnitude of the DC electricity generated by the solar panels  13 . 
         [0016]    The cart  11  comprises a handle  16  and a plurality of wheels  14  disposed on the undersurface thereof to provide mobility for the present invention. The mobility of the present invention allows the cart  11  to be moved between outdoor demonstrations, wherein the solar panels  13  can be charged via solar energy, to indoor demonstrations in which the energy that has been stored in the power source  15  can then be used to power various devices, demonstrating to individuals the benefits of clean energy. The cart  11  further comprises a storage area  21  beneath the support surface  12  for storing the various electrical components of the present invention. In the depicted embodiment of the present invention, the battery  15  and the reservoir  17  of the solar water heating system are held within the storage area  21 ; however, no claim is made as to the precise location of these components. The storage area  21  preferably further comprises one or more sidewalls extending therearound, preventing the contents of the storage area  21  from falling from the cart  11  during transport or being stolen therefrom if the cart  11  is left unattended. In one embodiment of the present invention, the sidewalls are constructed from poly(methyl methacrylate). 
         [0017]    Referring now to  FIG. 2 , there is shown a perspective view of the control panel of the present invention. The control panel  31  comprises a number of different electronic components or measurement devices that are used in conjunction with the systems of the present invention to run experiments and record data. The control panel  31  comprises an inverter  32 , a temperature control unit  33 , a multimeter  34 , an angle gauge  35 , a charge controller  36 , and a notification device  37 . In one embodiment of the present invention, the multimeter  34  is removably attached to the control panel via hook-and-loop fastening material or another such connector. In this embodiment, users can remove the multimeter  34  from the control panel  31  and test the electrical connections between the various electrical components of the present, such as the electrical connection between the solar panels and the bus to determine the amount of electrical energy being generated by the photovoltaic array. The angle gauge  35  indicates the angle at which the support surface  12  is disposed. This can be used by users to set the photovoltaic array at precise positions to either compensate for the changing position of the sun in the sky in order to maximize the amount of solar energy that impinges upon the photovoltaic array or run tests to determine the change in the amount of electrical energy generated by the solar cells as a function of the offset angle between the photovoltaic array and the sun. 
         [0018]    The inverter  32  comprises a conventional DC-AC inverter. The inverter  32  is electrically coupled to the battery and an output, which can in turn be connected to various loads or electronic devices not associated with the present invention. Therefore, after charging the battery using the photovoltaic array, users are then able to demonstrate that the battery has been charged by connecting external electronic devices, such as a television, to the battery and powering those electronic devices solely off of the solar-charged battery. 
         [0019]    The temperature control unit  33  is connected to the solar water heating system and indicates or displays the temperature of the water within the reservoir. When the temperature of the water reaches the desired temperature, the users can then choose to shut off the system to prevent overheating of the water. In an alternative embodiment, the temperature control unit  33  further comprises a safety shutoff that automatically deactivates the water pump when the temperature of the water has reached a pre-programmed value, thereby preventing water from being circulated through the solar water heating system and further heated beyond this value. 
         [0020]    The present invention further comprises a conventional charge controller  36 , which limits the rate at which current is supplied to or withdrawn from the battery in order to ensure the battery life of the battery is properly maintained. The charge controller  36  is useful because the photovoltaic array is a DC power source having a variable electrical output since the output is dependent upon environmental conditions, such as the degree of cloud cover, and other variables, such as the angle of the support surface  12  relative to the sun. The charge controller  36  protects against overvoltage and the damage to batteries that results therefrom. 
         [0021]    The present invention further comprises a notification device  37  disposed on the control panel  31 . The notification device  37  is adapted to indicate to users if the battery is being charged by the photovoltaic array and the magnitude of the electrical energy being generated by the photovoltaic array. The notification device  37  comprises a charge indicator  73 , which is activated by a first switch  71 , and an output indicator  74 , which is activated by a second switch  71 . In an exemplary embodiment of the present invention, the charge indicator  73  comprises a light that is activated when both the battery is receiving electrical energy from the photovoltaic array, i.e. being charged, and the first switch  71  has been actuated. This allows individuals to determine if there is an issue with the electrical connections between the photovoltaic array and the battery or if cloud cover is too substantial for the photovoltaic array to generate electricity. In an exemplary embodiment of the present invention, the output indicator  74  comprises a sound-generating device that emits an audible alert when the battery is being charged, wherein the rate at which the audible alerts are generated is proportional to the magnitude of the electrical energy being received by the battery. This allows users to ascertain the ideal positioning of the present invention, such as the physical location of the cart  11  and the angle of the support surface  12  relative to the sun, to maximize the amount of electrical energy generated by the solar panels. 
         [0022]    An alternative embodiment of the present invention further comprises a lock  51  for locking a cover (not shown) over the control panel  31 . A cover is slidably insertable along the slots  38  disposed on the sides of the control panel  31 . When the cover is in place, it covers the control panel  31  and prevents access to the various components thereunder. The cover has a size and shape conforming to the size and shape of the control panel  31 , allowing the cover to prevent access to the instrumentation therebelow when in place. Once the cover is secured in place along the slots  38 , the lock  51  can then be engaged to prevent the cover from being withdrawn from the control panel  31 . In the depicted embodiment of the present invention, the lock  51  comprises a U-shaped member to which a conventional padlock can be applied to secure the cover in place. The cover is preferably constructed from a durable, impact-resistant material, such as poly(methyl methacrylate). 
         [0023]    Referring now to  FIGS. 3 and 4 , there are shown a perspective view of the present invention with the solar panels removed therefrom, exposing the solar water heating panel disposed thereunder, and a schematic diagram of the water heating system of the present invention. The solar panels  13  are removably attached to the support surface  12 , over a solar water panel  81 . The solar panels  13  are removably connected to the support surface  12  via any means known in the prior art. When the solar panels  13  are removed from the support surface  12 , the solar water panel  81  thereunder is exposed and the solar water heating system can be activated. 
         [0024]    The solar water heating system comprises the water heating panel  81  disposed on the top surface of the support surface  12 , a water reservoir  17  disposed within the storage area beneath the support surface  12 , and a pump  101 . The pump  101  comprises a DC pump. The reservoir  17  comprises an outlet  102  that is connected to a first end of the water heating panel  81  and an inlet  103  that is connected to a second end of the water heating panel  81 . When the pump  101  of the solar water heating system is activated, it draws water  82  from the reservoir  17  and supplies it to the water heating panel  81 . The water  82  is then driven through the water heating panel, exposing the water  82  to the sun. As the water  82  is exposed to the sun, it is heated thereby. The water heating panel  81  comprises a transparent upper surface, an insulative lower surface, and an interior volume therebetween through which the water  82  is pumped. The large surface area of the water heating panel  81  maximizes the amount of solar energy to which the water  82  is exposed, which assists in heating the water  82  more quickly. Once driven through the water heating panel  81 , the water  82  is returned to the reservoir  17  and re-circulated through the system continuously until the water  82  is heated to a desired temperature. Once heated to the desire temperature, the system can be deactivated and then the water  82  can be removed from the reservoir  17  as desired by the user. 
         [0025]    An alternative embodiment of the present invention further comprises a temperature control unit  33  that controls the operation of the solar water heating system. The temperature control unit  33  comprises a first connection  104  to the inlet  103  and a second connection  105  to the outlet  102 . Using the first and second connections  104 ,  105  the temperature control unit  33  is adapted to measure the temperature of the water at various points in the system. Furthermore, the temperature control unit  33  is adapted to measure the temperature difference between the water entering the reservoir  17  and the water exiting the reservoir. If the temperature differential reaches unsafe levels, the temperature control unit  33  can automatically deactivate the pump  101  via an electrical connection  106  thereto. 
         [0026]    Although the depicted embodiment of the present invention is an active solar water heating system, no claim is made as to the specific type of solar water heating system utilized by the present invention. The present disclosure also contemplates the use of passive solar water heating systems as are conventionally known in the prior art. Furthermore, no claim is made as to the means by which the solar water heating system is activated. In one embodiment of the present invention, the solar water heating system comprises a sensor that detects the removal of the solar panels  13  from the support surface  12  and automatically activates the system in response thereto. In another embodiment of the present invention, the solar water heating system is activated by the user. 
         [0027]    In exemplary embodiments of the present invention, the power source for the pump  101  comprises one of the solar panels  13  or the internal rechargeable battery. In the former embodiment, the pump  101  is in electrical communication with one or more of the solar panels  13  and is powered thereby. In this embodiment of the present invention, the user removes all of the solar panels  13 , except for one solar panel  13 , which is left in place to power the pump  101 . Alternatively, the user can choose to leave more than one of the solar panels  13  in place to power the pump  101 ; however, this sacrifices surface area of the water heating panel  81 . In the latter embodiment, the pump  101  is powered by the integral battery, which was in turn previously charged by the solar panels. The latter embodiment of the present invention is suitable for simulation purposes for demonstrating the function of the solar hot water heating system to students in an indoor environment or if there is insufficient solar energy available to power the pump  101 . 
         [0028]    Referring now to  FIG. 5 , there is shown a block diagram of the electrical components of the present invention. The solar cells  121  are connected to the other electrical components of the present invention via the bus  122 , which allows users to change manner in which the solar panels are connected, i.e. in series or in parallel. The multimeter  123  provided with the invention is adapted to measure the voltage, current, and other such variables at the bus  122  to determine the amount of electrical energy being generated by the solar cells  121 . In one embodiment of the present invention, the bus  122  is then connected to the power source  125  by an inverter  124 , such as a solar inverter that compensates for the variable magnitude of the DC electricity generated by the solar panels. The current supplied to the power source  125 , i.e. the rechargeable battery, is limited by a charge controller  126 . Then in one embodiment of the present invention, the power source  125  supplies the energy for the pump  127  of the solar hot water heating system, as discussed above. In an alternative embodiment of the present invention, the pump  127  is supplied electrical energy via one or more of the solar panels, rather than the battery. 
         [0029]    It is therefore submitted that the instant invention has been shown and described in what is considered to be the most practical and preferred embodiments. It is recognized, however, that departures may be made within the scope of the invention and that obvious modifications will occur to a person skilled in the art. With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. 
         [0030]    Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.