MICROFICHE REFERENCE LIBFUUW - Cd3wd.com

1465.4.3 GeothermalLike tidal energy, geothermal (or terrestrial heat) energy is a “free’natural source of power which is being developed for .several uses, butas of yet- not directly for water lifting. In some areas it exists at theground surface naturally as geysers (e.g., Wairakei, New Zealand; Geysers,California), while in other places it can be reached by borehole. Currently ,geothermal heat is used to drive steam turbines for electric generationor for industrial processes (e.g., paper pulp). Its conversion directly tomechanical energy which could be used to drive water pumps is currentlyunfeasible (i .e., low torque) .5.4.4 SolarSolar energy is another source of “free” power which has just recentlyreached a level.lof technology development which provides for its conversionto mechanical energy. Unlike other natural resources, it exists in allareas of the world, although its degree of intensity varies with latitude,season, weather, and time of day. Although solar energy has long beenused for such purposes as heating and drying, the current world energysituations has spurred interest in making its use for these purposes moreefficient (i.e., for building heating, cooking, etc.) and in developingnew uses. Section 3.4.2.2 included a discussion of the use of solarheating to expand a working fluid which directly pumped water by the displacementmethod. Many other projects are underway by various researchorganizations to convert solar energy to mechanical energy which can thenbe used to do work such as pumping water.Near Mexico City, four prototype pumping plants are being used whichwill eventually (according to plans) be developed into a pumping system