MICROFICHE REFERENCE LIBFUUW - Cd3wd.com

As that vapor is condensing and returning to the flash tank, water isflowing into the second tank because of the decrease in pressure. Uponcompletion of these two simultaneous filling and discharging operations,the vapor is switched intothe other tank and the cycle repeated.A similar air-cooled system utilizes only one water tank which isemptied during the daylight heating hours, and filled during the coolingnight. This arrangement requires the water tank to be large enough tohandle one entire day’s pumping requirement.Early morning sunlight, from about 7-10 A.M., is required to bringthe working fluid to vaporization temperature, so that actual pumping canonly take place from about 10 A.M. to 4 P .M. With this time limitationin mind, the collector and tanks must be sized to produce the desireddaily discharge. Table 3.9 gives some of the results ach?eved by Rao andRao (1975) for various size systems. Theoretically, discharge is l.imitedonly by the size tanks available and lifts up to 300 ft should be withinpractical operation capabilities.Table 3.9Solar pump performanceAir-cooled system with Water-cooled system with10 x 12 ft water tank two 3 x 5 ft water tanksCollectorCollectorLift Discharge Area DischargeArea(ftl (ft3/darl m21(ft 3/dayl( ft21--------------------------------- ---30 880 250 7,805 1,00060 880 400 5,406 1,00090 880 550 3,607 1,000