MICROFICHE REFERENCE LIBFUUW - Cd3wd.com

144Although rarely in appropriate sites for irrigation or drainage waterlifting, tidal water is another form of natural energy which, if properlyharnesses, can provide an inexpensive source of power.Wave actionis a power source which has been adapted through variousschemes directly to mechanical energy which can and has been used to pumpwater. In Monaco, three horizontal,side-by-side rotors drive cammechanisms, which in turn reciprotate two double-acting piston pumps. Therotors are partially submerged about three feet from a cliff so as to berotated by both incoming waves from above and out-going undertow frombelow. Bob Morgan described another device called a Tea Horse" whichhe uses to drive a small electric generator, but could also be used todrive small water lifters directly (Eccli, 1974, pp. 102-104). As shownin Figure 5.8, this wavemill consists of two large, buoyant cylinders, sethalf of an average wavelength apart and each attached to a wire which passesunder a pulley directly below the cylinder. As the cylinders bob up anddown in the waves, they alternately pull (i.e., one rising while theother falling) on their respective wires. In Morgan’s design, these wiresdrive a ratchet wheel which provides a continuous rotating motion to aflywheel (conserves energy during non-power periods) which in turn drivesan electric generator. However, this same scheme could possibly be usedto drive reciprocating water lifters, utilizing just the cylinders andwires, or to provide rotary power with the added ratchet wheel andflywheel.Except for a few schemes, such as those mentioned, tidal power isstill an undeveloped source of natural energy.