Adaptive self pumping solar hot water heating system with overheat protection

A self pumping solar water heating system comprising:

• one, two or more solar collectors having vertical or upwardly sloped risers for heating heat transfer fluid and forming vapor bubbles in the risers,
• a lower manifold connected to lower ends of the risers,
• an upper header manifold connected to upper ends of the risers,
• exit tubes connected to the upper header manifold for lifting hot heat transfer fluid,
• a first reservoir connected to the exit tubes for receiving the hot heat transfer fluid from the exit tubes,
• a first pipe connected to the first reservoir,
• a heat exchanger connected to the first pipe for receiving hot transfer fluid from the first reservoir,
• a hot water tank connected to the heat exchanger,
• a second pipe connected to the heat exchanger for returning the cooled fluid,
• a second reservoir positioned below the first reservoir and connected to the second pipe,
• a return tube connected to the second reservoir and to the lower manifold, and
• a vapor pipe connected from an upper part of the first reservoir for flowing hot vapor from the first reservoir to the second reservoir to condense in the second reservoir, and
• a third closed and expandable reservoir for receiving vapor from the top of the second reservoir in the third closed and expandable reservoir and a float valve connected to a bottom of the third reservoir for opening to permit vapor and heat transfer fluid into the third reservoir and to permit heat transfer fluid to return from the third reservoir to the second reservoir.

A method of heating, comprising:

• providing a system with a solar collector with vertical or upward sloping risers,
• connecting upper and lower manifolds to the risers,
• providing heat transfer fluid in the lower manifold and in the risers,
• forming bubbles of hot vapor in the risers and driving slugs of hot heat transfer fluid upward through the risers, through the upper manifold and through exit tubes to a first upper reservoir, separating the hot vapor and hot fluid in the upper reservoir,
• flowing the hot heat transfer fluid through a first pipe and a heat exchanger for heating a second fluid,
• returning cooled heat transfer fluid from the heat exchanger through a second pipe to a second lower reservoir,
• receiving the hot vapor from the first reservoir in the second reservoir and condensing the vapor with the cooled heat transfer fluid therein, and
• flowing the cooled fluid to the lower manifold and continuing the method,
• providing a third reservoir, and
• flowing hot vapor from a top of the second reservoir to the third reservoir upon excess pressure in the system.

A method of heating, comprising:

• providing a system with a solar collector with vertical or upward sloping risers,
• connecting upper and lower manifolds to the risers,
• providing heat transfer fluid in the lower manifold and in the risers,
• forming bubbles of hot vapor in the risers and driving slugs of hot heat transfer fluid upward through the risers, through the upper manifold and through exit tubes to a first upper reservoir, separating the hot vapor and hot fluid in the upper reservoir,
• flowing the hot heat transfer fluid through a first pipe and a heat exchanger for heating a second fluid,
• returning cooled heat transfer fluid from the heat exchanger through a second pipe to a second lower reservoir,
• receiving the hot vapor from the first reservoir in the second reservoir and condensing the vapor with the cooled heat transfer fluid therein, and
• flowing the cooled fluid to the lower manifold and continuing the method, further comprising providing an adaptive system in which flow and temperature adjust automatically by increasing pressure in the system, flowing fluid and hot vapor from the second reservoir through a float valve to a third expandable reservoir, and returning the heat transfer fluid from the third reservoir to the system when the system pressure falls.