Abstract:
A solar water heater including an angularly inclined housing structure. The housing structure includes an inlet for receiving water and an outlet for discharging heated water. Encased within the housing, lies a plurality of heating pipes for absorbing solar energy. The plurality of heating pipes is operatively connected to the fluid inlet. The plurality of heating pipes encompasses a plurality of water storing pipes disposed therein. The plurality of water storing pipes is in fluid communication with the plurality of heating pipes and the fluid outlet. In this manner, the plurality of heating pipes act as a solar receiver, and the enclosed plurality of water storing pipes act as a storage tank. A solar water heating and storage device wherein a solar receiver and water storage tank are integrated into a single unit.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates generally to a solar water heater. More particularly, it pertains to a unitary solar heating and storing device. More specifically, water or any other liquid or gas could be heated. 
         [0003]    2. Description of Prior Art 
         [0004]    Numerous variations have been developed for solar water heaters. Typically, such devices include a housing comprising two primary, yet independent, components, interconnected to each other via a duality of passageways. More specifically, solar water heaters include a vertically oriented solar receiver for absorbing heat and conducting water, and a thermally insulated storage tank usually disposed immediately above the solar receiver. Solar receivers commonly include a series of equidistantly disposed, parallel heating pipes, thermo-mechanically connected to a blackened radiator. 
         [0005]    Such solar water heaters generally operate in a similar manner. The radiator absorbs solar energy, and heat is then imparted to the water within the pipes by conduction. In turn, the heated water decreases in density and begins to rise towards an upper passageway and into the storage tank. As the process continues, the cooler water within the tank is gradually displaced by the hotter and less dense, incoming water. As a result, the displaced cooler water descends towards a bottom passageway and into the heating pipes to be reheated. In this manner, hot and cold water continue to circulate so long as there is an appropriate temperature variance between the water within the solar receiver and that within the storage tank. 
         [0006]    Numerous embodiments of the aforementioned solar heater exist. For instance, solar water heaters may additionally utilize heat exchangers for heating the water, or such heaters may simply differ in construction. Notwithstanding the fact that many improvements have significantly increased the overall efficiency of solar water heaters, various drawbacks remain. For example, in the known embodiments, the heated water must flow through passageways, panels, heat exchangers, or the like, prior to entering the hot water storage tank. One drawback of such embodiments is that various impediments, e.g., friction, turbulence, drag, etc., hinder the water flow. Moreover, significant energy losses occur due to the connection of radiators, and/or the utilization of external water tanks and heat exchangers. Such energy losses result during the absorption of solar energy and its transformation to heat. 
         [0007]    Therefore, in order to promote the efficient use of energy, minimize cost, and reduce overall space, it would be advantageous to provide a unitary solar water heater, wherein external water tanks and radiators are not required. 
       SUMMARY OF THE INVENTION 
       [0008]    In accordance with the present invention, there is provided a solar water heater including an angularly inclined housing structure. The housing structure includes an inlet for receiving water (or any other liquid or gas) and an outlet for discharging heated water. Encased within the housing, lies a plurality of heating pipes for absorbing solar energy. The plurality of heating pipes is operatively connected to the fluid inlet. Additionally, the plurality of heating pipes encompasses a plurality of water storing pipes disposed therein. The plurality of water storing pipes is in fluid communication with the plurality of heating pipes and the fluid outlet. 
         [0009]    In this manner, the plurality of heating pipes act as a solar receiver, and the enclosed plurality of water storing pipes act as a storage tank. Hence, a solar water heating and storage device is provided wherein a solar receiver and water storage tank are integrated into a single unit. 
         [0010]    Other objects, features, and advantages of the present invention will become readily apparent from the following detailed description in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a perspective view of the preferred embodiment; 
           [0012]      FIG. 2A  is a cross-sectional view illustrating the internal construction of the plurality of heating pipes; 
           [0013]      FIG. 2B  is an enlarged cross-sectional view of the internal construction of the plurality of heating pipes shown in  FIG. 2A  taken along lines  3 - 3 ; 
           [0014]      FIG. 3  is a cross-sectional view of another embodiment, wherein the peak and valley portions are squared; and 
           [0015]      FIG. 4  is a cross-sectional view of another embodiment, wherein pipe-like channels formed from steel enclose pipes. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0016]    Referring generally to  FIGS. 1-2 , where like numerals indicate like and corresponding elements, a solar water heating and storage device in accordance with the invention is illustrated as including a unitary housing structure  10 . Any other liquid or gas could be heated in accordance with the present invention. The housing structure  10  includes a plurality of elongated heating pipes  12  disposed therein. Preferably, the plurality of elongated heating pipes  12  are equidistantly spaced apart and in parallel with each other. The heating pipes  12  can be formed from various materials known in the art, such as galvanized iron, stainless steel, copper, or other suitable material. Additionally, each heating pipe  12  comprises an external, heat-attracting surface  40  for absorbing solar energy. The heat-attracting surface can be formed with a suitable black paint or other selective absorbing material. The housing structure  10  can be in the form of a greenhouse box. 
         [0017]    The housing structure  10  further includes a transparent cover  20 , which may be composed of glass, plastic, or the like. If desired, the transparent cover  20  can include an anti-reflective coating. One embodiment of the present invention contemplates a transparent cover  20  comprising a pair of glass panes slightly spaced apart to define an intermediate gap. The gap can comprise thermal insulating means such as, but not limited to, air, gas, or vacuum. Importantly, and notwithstanding the embodiment, the housing structure  10  is angularly positioned such that the transparent cover  20  is exposable to the sun. In this manner, as sunlight passes through the transparent cover  20 , the heat-attracting surface  40  of the plurality of elongated heating pipes  12  absorbs solar radiation. 
         [0018]    In order to minimize energy losses and maximize heat efficiency, the housing structure  10  includes thermal insulation  42 . In one aspect of this invention, thermal insulation is provided to cover the areas of the heating pipes not exposable to sun. In this manner, thermal insulation can be efficiently provided to simply surround the areas wherein heated water is stored. 
         [0019]    As best illustrated in  FIGS. 2A and 2B , the plurality of elongated heating pipes  12  encases a plurality of elongated water storing pipes  14  of smaller diameter. In one embodiment, the plurality of elongated water storing pipes  14  are fixedly disposed on an internal, bottom surface of the plurality of elongated heating pipes  12 , such that the water storing pipes  14  are eccentrically positioned within. Each water storing pipe  14  includes a first open end  24 , and a second, opposite open end  34 . The plurality of elongated water storing pipes  14  can be formed from polyvinyl chloride (PVC), polybutylene (PB), or other suitable compressible material. 
         [0020]    The plurality of elongated heating pipes  12  and the plurality of elongated water storing pipes  14  fluidly communicate with each other via a pair of collectors  16 ,  18 . Both collectors  16 ,  18  are defined by fluid passageways adapted to receive and transfer fluid. In the preferred embodiment, each heating pipe  12  is interconnected to a bottom collector  16  at one end  22 , and to an upper collector  18  at a second opposite end  32 . The bottom collector  16  is operatively connected to a fluid inlet  26 , wherein cool water enters the solar water heating and storage device via the bottom collector  16 . The upper collector  18  is operatively connected to a fluid outlet  28  for dispensing hot water. For instance, if the invention is adapted to a water faucet, hot water exits the fluid outlet  28  and enters a hot water circuit connected to the faucet. Preferably, the housing structure  10  is angled so as to facilitate fluid flow via the process of natural convection. 
         [0021]    Analogous to the plurality of elongated heating pipes  12 , various materials can be used to construct the bottom and upper collectors  16 ,  18 , including, but not limited to, galvanized iron, stainless steel, copper, or other suitable material. If desired, the collectors  16 ,  18  can also include an external, heat-attracting surface  40 . Further, the heating pipes  12  and collectors  16 ,  18  may be interconnected by various means known in the art. For example, the two may be glued, welded, clamped, screwed, etc. Similar means may also be employed for securing the collectors  16 ,  18  and the plurality of elongated heating pipes  12  within the housing structure  10 . 
         [0022]    In operation, the heat-attracting surfaces  40  of the plurality of elongated heating pipes  12  absorb solar radiation. Via conduction, this absorbed energy is transferred to a volume water located in-between the heating pipes  12  and the water storing pipes  14 . As the aforementioned water becomes hotter, it expands and becomes less dense. By the process of natural convection, the heated water then rises and flows into the upper collector  18 . In turn, the heated water advances through the upper collector  18  and subsequently enters, via the second open end  34  of the water storing pipes  14 , into a cooler volume of water stored within the water storing pipes  14 . 
         [0023]    Simultaneously, due to its greater density, the cooler volume of water within the water storing pipes  14  begins to descend. The cool water exits the water storing pipe  14  via the first open end  24 , and advances into the bottom collector  16 . In turn, the cooler water flows throughout the bottom collector  16  and enters the volume of water located in-between the heating pipes  12  and the water storing pipes  14 , wherein the cooler water is heated in the foregoing manner. Generally, so long as sunlight is present, solar radiation will generate a temperature differential between the two bodies of water, i.e., the volume of water in-between the heating pipes and water storing pipes, and that within the water storing pipes. As such, water will continue to circulate in accordance with the aforementioned process. 
         [0024]    By encasing the plurality of elongated water storing pipes  14  within the plurality of elongated heating pipes  12 , the former set of pipes  14  functions as a water storing tank, and the latter functions as a solar receiver. Accordingly, integrating the two sets of pipes eliminates the need for providing a separate component for storing water. Such integration not only decreases overall surface area and thereby the costs generated by additional components, but moreover, significantly reduces energy losses and other common drawbacks associated with solar water heaters known in the art. 
         [0025]    The present invention additionally contemplates a nearly identical solar heating and water storing device, as shown in  FIGS. 3 and 4 . In this embodiment, however, the solar receiver component has been modified by the elimination of the plurality of elongated heating pipes  12 , and substituted with a metal sheet composite  38 . The metal sheets  38  can be bent, pressed, stamped, or otherwise fabricated to provide a rippled configuration. The rippled configuration includes peaks having a top surface  44  and a bottom surface  46 . When viewed in cross-section, the top and bottom surfaces  44 ,  46  include alternating peak and valley portions. As illustrated in  FIGS. 3 and 4 , depending on the fabrication method, these peak and valley portions can be squared, curved, or otherwise shaped. A flat metal sheet  36  having an external heat-attracting surface is optionally mounted over each of the top and bottom surfaces  44 ,  46  as shown in  FIG. 3 . Accordingly, the combination of the flat metal sheet  36  with the foregoing surfaces  44 ,  46  defines a series of corrugated grooves  50  wherein the plurality of water storing pipes  14  are encased therein alternating along the bottom surface  46  and the metal sheet  38  in mounted connection with the bottom surface  46 . Alternatively, as shown in  FIG. 4 , two metal sheets  38  can be combined with the top surface  44  of one metal sheet  38  in contact with the bottom surface  46  of a second metal sheet  38 , thereby forming the corrugated grooves  50 . In operation, the corrugated grooves  50  act as fluid passageways wherein incoming water is heated in the same manner as outlined above. 
         [0026]    The aforementioned metal sheets can be welded, glued, brazed, soldered, or otherwise joined together and mounted within the housing. One advantage provided by this embodiment is the reduction of the high costs associated with manufacturing a plurality of metallic pipes. This is especially true when the plurality of elongated water storing pipes is formed out of plastic-like material, since the composition of metal sheets entirely eliminates the need for utilizing metallic heating pipes. Hence, the foregoing embodiment provides a simpler and more cost efficient means for producing a solar water heating and storage device in accordance with the present invention. 
         [0027]    In another embodiment of the present invention, the bottom collector  16  comprises an electrical heating element for maintaining heat during prolonged lapses of sunshine. If desired, the electrical heating element can include standard safety interlocks disposed in either the bottom collector  16  or the upper collector  18 . For example, the electrical heating element can include a thermostat for regulating water temperature. Additionally, the electrical heating element can include a pressure regulator for maintaining water pressure within a maximum allowable level. 
         [0028]    In order to provide instant hot water, the electrical heating element can be installed within the upper collector  18 . With regard to this embodiment, the electrical heating element is preferably equipped with a flow switch sensitive to water flow. The flow switch can be installed in either the fluid inlet  26  or the fluid outlet  28 . Analogous to the thermostat and pressure regulator, the flow switch also functions as a safety interlock. For example, when hot water is drawn out, the flowing hot water actuates the switch so that the electrical heating element receives electrical power and heats the water exiting the upper collector  18 . Furthermore, when the hot water circuit is closed, the flow switch automatically turns off the electrical power. 
         [0029]    The invention has been described in an illustrative manner, and it is to be understood the terminology used is intended to be in the nature of description rather than of limitation. 
         [0030]    Obviously, many modifications and variations of the present invention are possible in light of the above teachings. For instance, while the present invention is more particularly directed to a solar water and heating device, the foregoing disclosure is also applicable to a heat exchanger. It is, therefore, to be understood that within the scope of the appended claims, the invention can be practiced otherwise than as specifically described.