Important
objectives include the
provision of a solar heating system which is self-pumping by means of
geyser pumping without use of electrical energy or pumps, yet which has
the desirable features of a pumped loop system, namely optimum location
of system components such as a storage receptacle located below the
solar collector; the provision of a system which is self-regulating and
operates on demand when the positive temperature difference between the
solar collector and the storage receptacle is great enough, requiring
no sensors, controllers, or valves; the provision of a system which
does not thermosiphon or pump backward when not operating and,
therefore, does not lose heat from the storage receptacle; the
provision of a system which requires little or no maintenance, has a
long lifetime and a low lifetime cost.
Click here to see
US patent 4,478,211 (PDF, 427 KB).
The first inventor of this patent, Eldon Haines, was co-founder of the
company that manufactured the Copper Cricket solar water heater, which
presumably incorporated the mechanism of the patent. There is a
story about Haines' low energy house at
http://www.solaror.org/ftp/SolarOregonJul04.pdf