Abstract:
A solar heating system for a hot water heater. The system has at least one solar heating unit that heats water contained therein and is fluidly connected to a water storage tank. The water storage tank is enclosed underneath the surface of the earth and is fluidly connected to the hot water heater in order to provide hot water to the hot water heater. An active over-heat protection system for the heating panels that tilts away from the sun when heating isn&#39;t needed. An active system that maintains proper water temperature in the storage tank during use of hot water and during reheating of water.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This invention relates to a system for supplying hot water to a hot water heater. More specifically, this invention relates to a solar heating system for a hot water system supplying domestic hot water and hot water for space heat. 
         [0002]    With the continuous rising cost of energy, individuals and companies have looked for a way of utilizing natural energy such as wind and solar power in order to supplement current forms of energy to reduce cost. Specifically, companies have begun providing systems that use solar energy in order to provide heat for a home and hot water heaters. An example of this can be seen at www.solarpanelsplus.com wherein heat pipes known as evacuated tube technology is presented in association with a solar heat exchanger in order to provide heat for a hot water heater. 
         [0003]    While such systems are effective at providing additional heat to a hot water heater these systems are very complex and difficult to maintain. Specifically, the system provides an anti-freeze in which the system has to transfer heat via a heat exchanger to the water. The addition of the heat exchanger provides additional cost and maintenance that minimize any cost savings from utilization of the system and presents a risk of water contamination by the anti-freeze liquid. 
         [0004]    Therefore, a principal object of the present invention is to provide a solar heating system for a water heater that is inexpensive to manufacture. 
         [0005]    Another object of the present inventions is to provide a solar heating system for a water heater that is efficient in collecting direct solar energy, flexible in location of the collector and able to supply hot water at maximum temperatures even when solar energy isn&#39;t being added to the water reservoir. 
         [0006]    Yet another object of the present invention is to provide a solar heating system for a hot water heater that provides additional water storage capacity. 
         [0007]    These and other objects, features or advantages of the present invention will become apparent from the specification and claims. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    A solar heating system for heating water and delivering it to a point of use. This system utilizes a plurality of heating units that have water enclosed therein such that the light from the sun is used to heat the water. The solar units are connected so that water within the units is urged to drain toward a water storage tank that includes a pump that supplies water to the solar heating units. The water storage tank is completely enclosed underneath the earth and thus insulated by the earth and additionally insulated via convention means. The tank is in fluid communication with a hot water heater in order to provide water to the facility of end-use. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a schematic diagram of a solar heating system; 
           [0010]      FIG. 2  is a perspective view of a solar heating unit; and 
           [0011]      FIG. 3  is a view of the solar panels and mount. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0012]      FIG. 1  shows a solar heating system  10  that utilizes a plurality of solar heating units  12  to harness solar energy from the sun  14  to heat water. The solar heating units  12  are best seen in  FIG. 2  and in a preferred embodiment include a double walled vacuum insulation tube  16  that preferably is a glass tube manufactured from a strengthened borosilicate glass. The heating unit additionally includes a black absorption inner layer  18 , a center heat transfer fin  20 , and a centering tube stopper  22  that utilizes a heat pipe condenser  24 . This preferred solar heating unit  12  shown in  FIG. 2  is conventional and known in the art as an evacuated tube wherein specifically the area between the inner and outer layers of the doubled wall vacuum insulation tube  16  are evacuated by a vacuum in order to keep heat from escaping into the atmosphere. In sum, the solar heating units  12  are designed to convert the light generated by the sun  14  into thermal energy in the interior of the unit  12 . 
         [0013]    The plurality of solar heating units  12  receive and contain water in its interior water manifold  25  shown as a copper header. Specifically, the plurality of solar heating units  12  that preferably are solar panels are fluidly connected to a storage water tank  26  having a recirculation pump  28  that is located underneath the surface of the earth to provide insulation from outside elements and cold. The plurality of solar heating units are angled such that gravity causes water within the units  12  to drain into the water storage tank  26  when recirculation pump  28  is not operating. The recirculation pump  28  pumps water from the interior of the storage water tank  26  to the plurality of solar heating units  12 . 
         [0014]    The recirculation pump  28  supplies water to a pipe system  30  that is fluidly connected to manifold  25  and is located in a support post  32  and has insulated pipe covers  34 . The solar panels  12  are mounted on the post  32  in such a manner that the panels  12  can be tilted to get an optimal angle to the sun, thereby collecting maximum energy. Alternatively, when overheating of the solar heating units  12  is detected by a sensor or the like a controller  35  pivots the units  12  away from the sun. When the panels  12  are tilted the pivoting point is also the point where insulated pipe covers  34  are attached to support post  32 . This communication of pipe and support posts  32  is done such that the tilting of the frame has a common axis with the insulated pipe covers  34  and not stress, force or impairment occurs upon the pipe covers or recirculation pipe when the frame is tilted. Because the pipe system  30  is closed loop, water pressurized by the recirculation pump  28  is directed to the manifold  25  in one solar panel, then to the second solar panel, and finally back to the origination point in the tank  26 . 
         [0015]    A hot water supply circuit  38  supplies water to a home and maximizes efficiency. The circuit  38  includes a thermostat  40  that measures the temperature of water coming from the storage tank  26  and supplied to pressure pump  42  that is fluidly connected to pressure switch  44  to supply water within supply water line  46 . The thermostat  40  is additionally electrically connected to a battery  48  that is also electrically connected to a solenoid valve  50  that is within a return line  52  where the solenoid valve similarly is electrically connected to the pressure switch  44 . The return line  52  has a relief valve  54  that is fluidly connected to the solenoid valve  50  and a thermo valve  56  that provides a fluid flow path between supply line  46  and return line  52 . Specifically, if the thermo valve or thermo bypass valve  56  detects that water in the supply line is below a threshold temperature the valve will open to recirculate cold water to a return line  52  to the storage tank  26 . If the temperature of the water is above a threshold temperature, the thermo bypass valve  56  closes allowing hot water in the supply line to feed the water to a water heater  58 . 
         [0016]    Water heater  58  can be a conventional water heater that heats water using electricity or the like as is known in the art. The water heater can include a mixing valve  60  that mixes in cold water to the water supplied by water heater  58  such that if the water in the storage tank  26  exceeds a predetermined temperature the mixing valve  60  supplies cold water to ensure an individual using the water is not scalded when using a faucet  62  fluidly connected to the water heater  58 . 
         [0017]    In operation, during the day when solar energy is available the recirculation pump  28  circulates water into the plurality of solar heating units  12 . The water within the plurality of solar heating units absorbs the energy that is transferred from the sun  14  through the solar heating units in order to heat the water. Because the plurality of solar heating units is angled the heated water flows back into the water storage tank  26  at night when the recirculation pump ceases. 
         [0018]    Additionally, when the water in tank  26  gets to a maximum temperature the standard system controller  35  shuts off power to the recirculation pump  28 . All of the liquid in panels  12  drain back to reservoir  26  leaving panels  12  exposed to the sun with no water to absorb the heat that is still collected. A controller monitors the panel  12  temperature and should it rise to a certain threshold temperature an electric actuator tilts the panels to a vertical position thereby significantly reducing the solar energy absorbed by the panels and limiting the temperature in the panels to a safe level. This tilting in order to shield the panels contrasts to conventional systems that may be roof mounted or not but which possess no system to limit solar energy uptake. Such systems often have a way to dump heated liquid into a cool down circuit. Those systems use energy to lose energy, have moving parts and a complex radiator system to lose heat. Simply tilting the panels away from the sun&#39;s rays is efficient, uses no energy save the tilt process itself and has no moving parts. 
         [0019]    When the water in the tank  26  has been heated the water can be supplied to the water heater  58 . The circuit  38  ensures that water is constantly supplied to the water heater  58  in an efficient manner. When the faucet  62  is turned on pressure drops and the pump  42  begins to operate so that an operating pressure is available at the faucet  62 . At this time the thermostat  40  is set so that it is closed when the temperature in the water tank  26  is above the predetermined temperature that is required to close thermo bypass valve  56 . Thus, when the faucet  62  is opened in the house, pressure drops in the water heater  58  and supply line  46  that closes pressure switch  44  as well as an internal pressure switch in pump  42 . This causes the variable speed pump  42  to run and maintain operating pressure but not cut off pressure. When the switch  44  closes in response to a reduced pressure, the solenoid valve  50  opens if the thermostat  40  is closed. 
         [0020]    So in an embodiment when the water temperature in the tank  26  is above the threshold temperature of thermo bypass valve  56 , when the faucet  62  is opened, pressure drops and the pump  42  starts so that operating pressure is available to the faucet  62 . The solenoid valve  50  is activated because thermostat  40  is closed as a result of the water being above the threshold temperature. In an embodiment such as when water has not been used overnight and cold water is presented in the supply line  46  is below the threshold temperature, the thermo bypass valve  56  opens allowing water to pass through to the return line  52 . The cold water in the return line  52  passes through the relief valve  54  and through the open solenoid valve  50  to the tank  26 . Thus, pressure at the faucet  62  is able to be regulated by the relief valve  54  as reduced from normal operating pressure, allowing the line from the water heater  58  to the faucet  62  to fill with hot water while at the same time supply line  46  fills with hot water. Consequently, a majority of the cold water is purged from the supply line  46  and returned to the tank  26  because the relief valve  54  maintains only reduced pressure at the faucet  62 . 
         [0021]    Once the water in the supply line  46  is above the predetermined temperature the thermo valve  56  closes and no water returns to the storage tank  26  via the return line  52 . At the same time the full pressure of the pump  42  is realized at the faucet  62 . The fact that some cold water has been put into the water heater  58  is insignificant because water in the storage tank  26  is potentially hotter than the temperature that hot water heaters normally run. Thus, the cool water helps prevents scalding. In addition, the mixing valve  60  can be utilized to add additional cold water again to prevent over heating or scalding as a result of raised temperatures at the water storage tank  26 . 
         [0022]    Alternatively, in an embodiment where the temperature of the water in the storage tank  26  is below the threshold temperature of the thermo valve  56  the thermostat  40  is open and the solenoid valve  50  closes. This eliminates any return water and causes the full pressure of the pump  42  to be present at faucet  62 . In this case any cold water in the supply line  46  goes to the hot water heater  58  from tank  26  and the hot water heater  58  acts in a normal fashion as is known in the art. 
         [0023]    Once the sun  14  goes down the recirculation pump  28  stops recirculating water. This occurs by either a timer on the pump or alternatively a sensor that detects the presence of light from the sun. Because the plurality of solar heating units  12  are angled the water from within the solar heating units  12  drain into the water storage tank  26 . The system of draining water back when there is no heat from the sun saves the energy that exists in the water normally residing in the pipe system  30  as well as manifold or header  25  from being lost overnight. The next day when solar energy is available there is no wasted time and energy heating cold liquid. Additionally, no freeze damage or pipe plugging can occur since there is no water in the lines above ground. Furthermore, the fact that water is directly heated, and not heated indirectly by means of heat transfer from an anti-freeze solution means that the system saves one step that otherwise would contribute to lowering the over all efficiency of the system. 
         [0024]    Thus, presented is a solar heating system  10  that directly heats water and does not use anti-freeze or transfer heat via a heat exchanger to the water. The system  10  presents a drain back system that is both simplistic and economical. The plurality of solar heating units  12  are tilted slightly in order to drain water to one end such that when the recirculation pump  28  shuts off, the water drains back into the water storage tank  26 . Because the water storage tank  26  is buried underneath the earth the tank is well insulated and maintains the temperature of the water heated therein. Thus, by locating the water tank  26  in the ground prevents freezing of the water even if the water is not heated for stretches of time. Due to insulation surrounding the water pipe in support post  32  and insulated pipe covers  34 , the water effectively is shielded from cold and therefore loses very little, if any, energy enroute to and from the solar heating units which add energy in the form of heat to the water as it travels through the manifold(s)  25  in the solar heating units  12 . The very short distance the water travels and the fact that it travels the entire route in insulated pipes makes the system extremely efficient in harnessing solar energy. 
         [0025]    The system  10  also minimizes the pipe length from the water storage tank  26  to the solar heating units  12 . By minimizing the distance that the fluid has to move, minimizes the parasitic energy lost from traveling this distance. In addition, because the water storage tank  26  is placed in the ground the system can be located anywhere a user desires in order to maximize exposure to the sun, maximizing efficiency during the heating process. In addition, by draining the fluid back into the tank  26  at night there is no heat loss overnight to the atmosphere, and the next morning the solar heating units  12  merely need to be reheated. 
         [0026]    The delivery of the hot water to the house is done with the pump  42  and located at the tank  26 . If the water in the ground is cool because no hot water has been used for some time, the system sends most of the water back to the tank  26  via a return line. Once the water supply to the house is hot the thermo bypass valve  46  shuts off and only very hot water is sent into the hot water heater  44 . Because the system  10  supplies the hot water heater  44  the original hot water heater  44  becomes an extra supply tank that has conventional heat backup. 
         [0027]    In addition, as compared to the prior art, in the prior art when hot water is used then cold water replaces the hot water in a solar tank thereby immediately reducing the temperature of the solar tank water supply. In the present system  10  no cold water goes in unless the sun is up and heat is available. Thus, unless the solar tank is depleted of water there is only hot water supplied to the house. 
         [0028]    Thus presented is a system  10  that uses a drain back system incorporated with evacuated tubes and direct water heat to drive water to a ground mounted storage tank  26  located close to the solar heating units and in the ground. The solar heating units  12  are mounted on a tilt capable stand to get the best angle to the sun  14  such that only hot water is delivered to the house when the solar heated water is available. Therefore, at the very least all of the stated objectives have been met. 
         [0029]    It will be appreciated by those skilled in the art that other various modifications could be made to the device without departing from the spirit and scope of this invention. All such modifications and changes fall within the scope of the claims and are intended to be covered thereby.