Abstract:
A solar powered portable water heating apparatus using extra low voltage (ELV) components including a recirculating pump that is controlled by a control system to recirculate a contained body of water past a heating element. Over a period of time, the temperature of the water in the contained body of water is increased. The apparatus stops when either there is insufficient electrical power generated by the solar panel(s), or the temperature of the water is sensed to have reached a set temperature.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to portable water heating apparatus, and in particular, water heating apparatus that is electrically powered by solar panels, and acts upon a contained body of water in order to raise its temperature over time. 
       BACKGROUND OF THE INVENTION 
       [0002]    Heated water is required in many situations. One of the most common uses for it in residential situations is in Jacuzzis. Having an effective water heating facility on the contained body of water in the Jacuzzi enables the Jacuzzi to be used all year round. 
         [0003]    In addition to this use, it is also often desirable to have a body of heated water to use when spending time outdoors, for example when camping or fishing etc. 
         [0004]    There are several techniques commonly used to heat a contained body of water. One common technique uses a mains powered pumping means to pump water from a portable pool or portable Jacuzzi and pumps the water through a solar water heating blanket that is typically installed on a nearby roof. Even though this arrangement uses solar power to heat the water, it still requires a separately powered pump to pump the water through it. Also this type of arrangement is not very portable as you would be required to roll up the heating blanket each time you wish to move it. It is also more difficult to run water piping to and from the blanket to complete the water circuit. Any sensor equipment used to determine the temperature in the contained body of water also needs to be separately powered, which is often difficult to do in remote areas where people camp. 
         [0005]    Another common type of solar hot water uses a solar collector that circulated water through a piping circuit that includes a coil that is within an insulated storage tank of water. As water is utilised from the storage tank, fresh water is permitted to flow into the storage tank in order to maintain the water level inside the storage tank. The solar collector is efficient at transferring solar energy into thermal energy to heat the water in the piping circuit. The solar collector does not generate electricity, so the pump that is used to pump the water around the piping circuit is separately powered. Additionally, any controller means or associated sensors, such as temperature sensors, need to be separately powered. These systems are not designed for portability. They are not typically able to be dis-assembled for storage and transport, and the storage tank often requires pressure relief apparatus in case of overpressure, and associated inspection and certification. 
         [0006]    The present invention seeks to provide a portable solar powered water heating system for a contained body of water which may be used to address one or more of the disadvantages associated with water heating installations of the type described above. 
       DISCLOSURE OF THE INVENTION 
       [0007]    Accordingly, the present invention is a portable solar heating apparatus for heating a contained body of water, the apparatus including:
       at least one temperature sensor, and   a heating element, and   a control system, and   a pump, and   a transient water tank, and   at least one solar panel.       
 
         [0014]    The operation of the pump is controlled by the control system, and the control system is fed data from the at least one temperature sensor, which is adapted to sense the temperature of the water in the body of water, and the heating element is located within the transient water tank, so that while the system is in operation, the pump is adapted to draw a portion of water from the body of water and discharge it into the transient water tank. The water occupies the transient water tank for a period of time and acquires thermal energy via the action of the heating element, then flows from the transient holding tank back into the body of water. The inflow of the heated water adds its thermal energy to the body of water, thereby raising the temperature of the body of water. The control system continues to recirculate water from the body of water through the transient holding tank until the apparatus either runs out of sufficient electrical power to operate, or the temperature of the water in the body of water is sensed, by the temperature sensor, to have risen to the temperature set by an operator of the apparatus. The at least one solar panel provides 100% of the electrical energy required to drive the pump, heating element, control system and its associated sensors. 
         [0015]    Preferably the at least one solar panel is fitted with sensors that are used to measure the ambient conditions at the panel, such as light intensity and ambient temperature, and the sensors feed the data they collect back to the control system. 
         [0016]    Preferably the solar panel has adjustable resistance means that are controlled by the control system, and the control system analyses the data it receives from the solar panel sensors to continuously adjust the resistance applied to the solar panel, via the adjustable resistance means, to keep the solar panel operating at peak electrical efficiency for the current prevailing environmental conditions. 
         [0017]    Preferably the apparatus utilises extra low voltage components to minimise the risk of electrical shock and to minimise the need for statutory electrical safety certification. 
         [0018]    Preferably the apparatus is able to be dis-assembled and packed away for storage and portability when not in use. 
         [0019]    Preferably the transient water tank also acts as a protective housing, even when the portable heating apparatus is dis-assembled, so that the heating element and the sensors housed within it are protected, and also prevents a user from making accidental contact with the heating element. 
         [0020]    Preferred aspects of the invention will be described with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  shows a schematic diagram of a portable solar water heating apparatus in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0022]    Referring to  FIG. 1 , we are shown a preferred embodiment of the present where the portable water heating apparatus  1  consists of a solar panel  3  that is connected to and controlled by the control system  13 . The control system  13  also controls the pump  5 . In this example, the pump  5  is shown as a submerged pump, however any type of pump can be used. The pump  5  is adapted to draw water out of the body of water  15  and discharge it into the top of the transient water tank  11 . The heating element  9  is adapted to heat the water in the transient water tank. The drawn water spends a period of time transiting through the transient water tank  11  where it is acted upon by the heating element  9 . The heated water then flows out of the outlet  17  and flows back into the body of water  15 . The transient water tank temperature sensor  7  and the temperature sensor  19  that is located in the body of water  15  feed the temperature date they collect back to the control system  13 . The control system analyses the data the sensors collect and operates the pump to recirculate the water in the body of water  15  through the apparatus until the temperature of the water in the body of water  15  reaches a set temperature, set by the operator of the apparatus. The solar panel  3  provides 100% of the electrical energy for the apparatus. The setup, operation and status of the apparatus is displayed on the control system  13  via display panel  21 . 
         [0023]    The major advantage of the invention is the fact that it is portable, and can be dis-assembled and compactly stored for enhanced portability. The heating element  9  and the temperature sensor  7  are fully housed inside the transient water tank  11 , and the body of the tank is durable and protective so that the heating element  9  is always protected when dis-assembling or assembling the apparatus, or transporting it. The tank also prevents the accidental contact with the heating element. 
         [0024]    The apparatus can be used with any standing body of water like a Jacuzzi or a water drum. This makes it very convenient and useful to take camping. 
         [0025]    The electrical efficiency of the solar panel  3  changes as ambient conditions in its vicinity change. To keep the solar panel at peak electrical efficiency, the resistance needs to be varied. Optionally an additional set of sensors are included that are capable of sending relevant ambient condition data such as ambient temperature and light intensity back to the control system  13  where it is analysed, and the control system  13  then uses that data to continuously adjust the resistance to the solar panel. 
         [0026]    The apparatus uses Extra Low Voltage (ELV) components. This significantly reduces the risk of electrical shock and also has the added advantage of minimising, or eliminating the need for statutory electrical approval in many jurisdictions. 
         [0027]    In use, the water in the body of water  15  is continuously recirculated through the apparatus. Each pass through raises the temperature of the water a small amount. It typically takes several hours of continuous operation to raise the temperature of the water in the body of water up to the set temperature. This makes it an ideal device for heating a Jacuzzi during the day so that it is ready for use in the later afternoon or evening, or for all kinds of outdoor and/or remote activity such as camping or fishing. Any suitable water container can be used such as a bucket or drum. The water can either be transported to the camp, or retrieved from a local river, stream or lake etc. 
         [0028]    The capacity of the apparatus can be adjusted by adding extra solar panels to match prevailing solar and ambient conditions. 
         [0029]    In a preferred embodiment, the apparatus utilises Maximum Powerpoint Tracking (MPPT) technology to optimise the electrical performance of the solar panel, or panels, in order to provide the extra low voltage components of the apparatus with a moderated electrical power supply that accounts for variations in ambient weather and light conditions encountered by the solar collector panel. It should be noted that no battery is used in the apparatus. 
         [0030]    Finally, it should be acknowledged that the apparatus of the present invention is not an instant water heating system. It is a slow iterative process that relies on the water in the contained body of water to recirculate many times past the heating element in order to gradually raise the temperature of the water in the contained body of water. 
         [0031]    While the above description includes the preferred embodiments of the invention, it is to be understood that many variations, alterations, modifications and/or additions may be introduced into the constructions and arrangements of parts previously described without departing from the essential features or the spirit or ambit of the invention. 
         [0032]    It will be also understood that where the word “comprise”, and variations such as “comprises” and “comprising”, are used in this specification, unless the context requires otherwise such use is intended to imply the inclusion of a stated feature or features but is not to be taken as excluding the presence of other feature or features. 
         [0033]    The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that such prior art forms part of the common general knowledge.