Convection Driven Two-Component Solar Water Heater Using All-Glass Evacuated Tubes with a Heat Separator

Abstract

A solar water heater including a heat separator containing either a single partition wall that connects in parallel colder water entering all-glass evacuated tubes with hotter water exiting the same all-glass evacuated tubes, or a number of partition walls that connect in series colder water entering each all-glass evacuated tube with hotter water exiting each all-glass evacuated tube. As water in the evacuated tubes is heated by solar radiation, a hydrodynamic head is created which forces the hot water in the evacuated tubes to flow automatically into the hot water compartment(s) of the heat separator(s) and subsequently through an insulated pipe to a water tank without requiring a pump. The cool water in the water tank flows automatically through an insulated pipe back into the cool water compartment(s) of the heat separator(s) in order to preserve flow continuity.

1 . A solar water heater comprising:
 at least one heat separator comprising:
 a heat separator body and one or more partition walls which extend through a number of holes formed in the heat separator body; and 
 at least one outlet fitting connecting with a first water compartment in the heat separator body and at least one inlet fitting connecting with a second water compartment in the heat separator body, the temperature of the first water compartment being higher than the temperature of the second water compartment; 
   a plurality of all-glass evacuated-tube solar thermal energy collectors each fitted into a corresponding one of the holes in the heat separator body, the one or more partition walls separating each hole into two halves, with one half of each hole connecting to a first area of a corresponding one of the plurality of all-glass evacuated tubes and the other half of the same hole connecting to a second area of the corresponding one of the plurality of all-glass evacuated tubes, the temperature of the first area being higher than the temperature of the second area;   a gasket placed in each hole and each all-glass evacuated tube to maintain the heat separator and all-glass evacuated tubes water tight; and   at least one insulated tank connected with the at least one heat separator by at least two insulated pipes.   
     
     
         2 . The solar water heater of  claim 1 , wherein the all-glass evacuated tubes are placed vertically or with an angle inclined towards the sun, with the heat separator placed horizontally and comprising a one-piece partition wall which connects in parallel colder water entering the evacuated tubes with hotter water exiting the evacuated tubes. 
     
     
         3 . The solar water heater of  claim 1 , wherein the all-glass evacuated tubes are placed vertically or with an angle inclined towards the sun, with the heat separator placed horizontally comprising a plurality of partition walls which connect in series colder water entering the evacuated tubes with hotter water exiting the evacuated tubes. 
     
     
         4 . The solar water heater of  claim 1 , wherein the all-glass evacuated tubes are placed horizontally on one or both sides of the heat separator, the heat separator is placed vertically or with an angle inclined towards the sun, and the heat separator comprises a one-piece partition wall which connects in parallel colder water entering the evacuated tubes with hotter water exiting the evacuated tubes. 
     
     
         5 . The solar water heater of  claim 1 , wherein the all-glass evacuated tubes are placed horizontally on one or both sides of the heat separator, the heat separator is placed vertically or with an angle inclined towards the sun, and the heat separator comprises a plurality of partition walls which connect in series colder water entering the evacuated tube with hotter water exiting the evacuated tube. 
     
     
         6 . The solar water heater of  claim 1 , wherein the heat separator is encased by at least one of thermal insulation an an outer layer of damage resistant material. 
     
     
         7 . The solar water heater of  claim 1 , wherein the insulated tank comprises a heat exchange coil. 
     
     
         8 . The solar water heater of  claim 1 , wherein the insulated tank contains a phase-transition heat storage material. 
     
     
         9 . The solar water heater of  claim 8 , wherein the phase-transition heat storage material is paraffin wax. 
     
     
         10 . The solar water heater of  claim 1 , wherein a reflecting surface is placed on an underside of the all-glass evacuated tubes. 
     
     
         11 . The solar water heater of  claim 1 , wherein the insulated tank contains a secondary heating element. 
     
     
         12 . The solar water heater of  claim 1 , wherein the insulated tank contains a thermostat. 
     
     
         13 . The solar water heater of  claim 1 , further comprising an overheat release device on at least one of the insulated tank or the heat separator. 
     
     
         14 . The solar water heater of  claim 1 , wherein the heat separator body has a rectangular box shape. 
     
     
         15 . The solar water heater of  claim 1 , wherein the water tank is made of plastics. 
     
     
         16 . The solar water heater of  claim 1 , wherein the heat separator body and the partition walls are made of plastics. 
     
     
         17 . The solar water heater of  claim 1 , wherein the heat separator body is made of metal. 
     
     
         18 . The solar water heater of  claim 1 , wherein the all-glass evacuated tubes have three concentric glass tubes with an inner tube filled with low-pressure air and separated by metal supporters. 
     
     
         19 . The solar water heater of  claim 1 , wherein the all-glass evacuated tubes are placed on one or both sides of the heat separator with an angle away from the sun, the heat separator is placed vertically or with an angle inclined towards the sun, and the heat separator comprises a one-piece partition wall which connects in parallel colder water entering the evacuated tubes with hotter water exiting the evacuated tubes. 
     
     
         20 . The solar water heater of  claim 1 , wherein the all-glass evacuated tubes are placed on one or both sides of the heat separator with an angle away from the sun, the heat separator is placed vertically or with an angle inclined towards the sun, and the heat separator comprises a plurality of partition walls which connect in series colder water entering the evacuated tube with hotter water exiting the evacuated tube.