Solar energy augmented water heating system

A solar energy augmented water heating system, such as a domestic hot water system, comprising:

• a water storage and heating tank including a water heater,
• a solar energy storage tank,
• means for conducting water through said solar tank and then through said water tank,
• a solar collector,
• heat transport liquid recirculating means defining a normal liquid recirculating flow path through said collector and solar tank and a cascade recirculating liquid flow path through said collector, said water tank, and then said solar tank, and
• means for circulating a heat transport liquid through said normal flow path when t.sub.c exceeds t.sub.s and t.sub.w at least equals a preset set point temperature t.sub.h and through said cascade flow path in response to at least one of the conditions (a) t.sub.c exceeds t.sub.w and t.sub.w is less than t.sub.h, and (b) t.sub.c exceeds t.sub.w by a preset temperature differential.

A solar energy augmented water heating system, such as a domestic hot water system, comprising:

• a water storage and heating tank, including a water heater,
• a solar energy storage tank,
• means for conducting water through said solar tank and then through said water tank,
• a solar collector,
• means for conducting a heat transport liquid through said collector and tanks, including valve means having normal and cascade positions, means defining a normal transport liquid flow path from said collector, through said valve means and said solar tank back to said collector when said valve means occupies said normal position, and a cascade transport liquid flow path from said collector through said valve means, said water tank, and then said solar tank back to said collector when said valve means occupies said cascade position,
• pump means for pumping said transport liquid through said flow paths, and
• control means responsive to the collector temperature t.sub.c, the solar tank temperature t.sub.s, and the water tank temperature t.sub.w for controlling said pumping means and valve means to recirculate said heat transport liquid through said first flow path when t.sub.c exceeds t.sub.s and t.sub.w at least equals a maximum set point temperature t.sub.h and through said cascade flow path in response to at least one of the conditions:
• (a) t.sub.c exceeds t.sub.w and t.sub.w is less than t.sub.h, and (b) t.sub.c exceeds t.sub.w by a preset temperature differential.

A solar energy augmented water heating method comprising the steps of:

• conducting water to be heated through a solar energy storage tank and then through a water storage and heating tank including a water heater,
• activating said heater when the water temperature in said water tank drops below a minimum set point temperature t.sub.l and inactivating said heater when the water temperature in said water tank rises to a maximum set point temperature t.sub.h,
• circulating a heat transport liquid through a solar collector and said solar tank when the collector temperature t.sub.c exceeds the solar tank temperature t.sub.s and the water tank temperature t.sub.w at least equals t.sub.h and through said collector, said water tank, and then said solar tank in response to at least one of the conditions:
• (a) t.sub.c exceeds t.sub.w and t.sub.w is less than t.sub.h, and (b) t.sub.c exceeds t.sub.w by a preset temperature differential.

A solar energy augmented water heating system, such as a domestic hot water system, comprising:

• a water storage and heating tank including a water heater,
• a solar energy storage tank,
• means for conducting water through said solar tank and then through said water tank,
• a solar collector, and
• means for circulating a heat transport liquid selectively either through said collector and said solar tank or through said collector, said water tank, and then through said solar tank.

A solar energy augmented water heating system, such as a domestic hot water system, comprising:

• a water storage and heating tank including a water heater,
• a solar energy storage tank,
• means for conducting water through said solar tank and then through said water tank,
• a solar collector,
• means defining a normal liquid recirculating flow path through said collector and solar tank and a cascade recirculating liquid flow path through said collector, said water tank, and then said solar tank, and
• means for circulating a heat transport liquid selectively through said normal flow path and through said cascade flow path.

A solar energy augmented water heating system, such as a domestic hot water system, comprising:

• a water storage and heating tank, including a water heater,
• a solar energy storage tank,
• means for conducting water through said solar tank and then through said water tank,
• a solar collector,
• means for conducting a heat transport liquid through said collector and tanks, including valve means having normal and cascade positions, means defining a normal transport liquid flow path from said collector, through said valve means and said solar tank back to said collector when said valve means occupies said normal position and a cascade transport liquid flow path from said collector through said valve means, said water tank, and then said solar tank back to said collector when said valve means occupies said cascade position, and
• pump means for pumping said transport liquid through said flow paths.