MICROFICHE REFERENCE LIBFUUW - Cd3wd.com

1362500-3500 rpm to deliver 150-200 gpm at a pressure of 20 psig to thesprinklers. The system was supplemented by a diesel engine for windlessperiods (Ionson, 1969) .Table 5.3 gives some typical water lifting applications of windmills.In general, since wind is a variable power source, two precautions areusually taken to insure water is available when needed. As in the Bracestudy, an auxiliary power source (e.g., gas engine, electric motor) iskept in reserve for times of low or no wind. The other alternative is toprovide a storage facility, e.g., a pond or tank (Figure 5.2), which iscapable of holding sufficient water for the longest expected period ofwindless days. When a rotodynamic pump is powered by a windmill, theinstallation must provide the pump with a dynamic suction head or an automaticallyregulated supply of priming water to insure the necessary primeneeded for pump operation-- see Fateyev (1948), p. 277 (in translation).Except for occasional adjustments and lubrication, windmills have almostno operatingcosts.5.4.2 WaterWhere a sufficient flow or head of water exists, the energy of thiswater can be used to rotate a watermill, which can then be used to driveseveral types of water lifters. (To avoid confusion, it is convenient torefer to wheel devices which receive energy from water as “watermills”(just as windmills receive wind energy), and those which impart energy towater (e.g., noria, tympanum, etc .) as “waterwheels”--see Reynolds, 1070.)Depending on the amount of availableflow or head, one or more types ofwatermills may fit the given installation and intended water lifter(s)