Solar Water Heater

Abstract

A solar water heating apparatus comprising inner and outer concentrically arranged vessels; a cavity defined between the vessels by an outer wall of the inner vessel and an inner wall of the outer vessel; a liquid-to-vapour phase change material provided in the cavity; an inlet for delivering unhealed water to the Inner vessel; and an outlet or withdrawing heated water from the inner vessel, and a pump which pumps the phase change material towards the inner wall of the outer vessel.

1 . A solar water heating apparatus comprising inner and outer concentrically arranged vessels; a cavity defined between the vessels by an outer wall of the inner vessel and an inner wall of the outer vessel; a liquid-to-vapour phase change material provided in the cavity; an inlet delivering unheated water to the inner vessel; and an outlet withdrawing heated water from the inner vessel, and means for pumping the phase change material towards the inner wall of the outer vessel. 
     
     
         2 . A solar water heating apparatus comprising inner and outer concentrically arranged vessels; a cavity defined between the vessels by an outer wall of the inner vessel and an inner wall of the outer vessel; a liquid-to-vapour phase change material provided in the cavity; an inlet delivering unheated water to the inner vessel; and an outlet withdrawing heated water from the inner vessel; wherein a plurality of fins it provided on an outer wall of the outer vessel. 
     
     
         3 . The apparatus of  claim 2 , further comprising pockets formed inside the cavity to retain liquid-to-vapour phase change material and to regulate its downward flow. 
     
     
         4 . The apparatus of  claim 2 , further comprising means for pumping the phase change material towards the inner wall of the outer vessel. 
     
     
         5 . The apparatus of  claim 1 , wherein the liquid-to-vapour change material is water. 
     
     
         6 . The apparatus of  claim 1 , wherein the means for pumping is a liquid suction pump. 
     
     
         7 . The apparatus of  claim 6 , wherein the pump is a DC liquid suction pump. 
     
     
         8 . The apparatus of  claim 1 , wherein the means for pumping is solar powered. 
     
     
         9 . The apparatus of  claim 8 , wherein the means for pumping is powered by means of an integral photovoltaic panel. 
     
     
         10 . The apparatus of  claim 1 , wherein the means for pumping is located towards the base of the apparatus and pumps the liquid from phase change material towards the top of the apparatus. 
     
     
         11 . The apparatus of  claim 1 , further comprising at least one reservoir within the cavity and within which reservoir at least a portion of the phase change material may be retained or redirected to improve the heat transfer and evaporation process. 
     
     
         12 . The apparatus of  claim 11 , comprising an evacuated compartment disposed within the inner vessel and defining at least one of the reservoirs between the compartment and an inner face of the outer vessel, by direct flow or via a heat exchange mechanism. 
     
     
         13 . The apparatus of  claim 1 , wherein the inlet feeds into a lower portion of the inner vessel and the cutlet is supplied from an upper portion of the inner vessel. 
     
     
         14 . The apparatus of  claim 13 , wherein the outlet returns through the inner vessel before exiting the outer vessel. 
     
     
         15 . The apparatus of  claim 1 , further comprising a heat exchanger connected between the inlet and the outlet. 
     
     
         16 . The apparatus of  claim 1 , wherein a solar radiation absorbent coating is provided on an outer face of the outer vessel. 
     
     
         17 . The apparatus of  claim 1 , further comprising a divider disposed within the outer vessel between an upper end of the inner vessel and an upper end of the outer vessel in order to reduce vapour heat transfer losses through the upper end of the outer vessel. 
     
     
         18 . The apparatus of  claim 1 , further comprising a transparent cover vessel located about the outer vessel. 
     
     
         19 . The apparatus of  claim 3 , further comprising means for pumping the phase change material towards the inner wall of the outer vessel. 
     
     
         20 . The apparatus of  claim 2 , wherein the liquid-to-vapour change material is water.