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Solar energy installations for pumping irrigation water
Solar Eaal/y Vol. 21, pp. 255-262 PergamonPress Ltd., 1978. Printed in Great Britain
0038--092~8/1001-0255/$05.00/0
REVIEW PAPER
SOLAR ENERGY INSTALLATIONS FOR PUMPING IRRIGATION WATER J. T. PYTLINSKI New Mexico Solar EnergyInstitute, New Mexico State University, Las Cruces NM 88003, U.S.A. (Received 5 October 1977;revision accepted 8 May 1978)
mirror (45° cones) to focus solar radiation on a copper Solar radiation reaching the surface of the earth is in- boiler located along the axis of the cone. The boiler was termittent due to atmospheric conditions and the rotation blackened to enhance absorptivity and covered with glass to reduce heat losses. The entire apparatus could be of the earth. This intermittence and variability inherently limit the useful conversion of solar radiation by requiring swiveled by hand to follow the sun. Mouchot demonstrated his first solar engine in Paris in either intermediate storage of energy or application to a 1866. He constructed a second engine in 1875 with task where intermittency is acceptable. The pumping of irrigation water is an operation where financial assistance from the French government. This normally intermittent operation may be acceptable. This engine had a reflecting surface area of 4 m z and an axial fact, plus the potential economical benefits to be boiler 0.8 m long. It produced steam at 50.7 x 10' N/m 2 obtained, has ingigated the research in this area. And and 426°K. The pressure was reduced to 20.3 x 104N/m 2 since this problem is basically that of converting solar and the steam was used to operate a small reciprocating radiation to mechanical energy, it is very much related to engine at 80 strokes per min. Later it was used to power past efforts to develop "solar engines" which might be a rotary engine driving a water pump. The inventor claimed a power of 0.5 h.p. used for a number of purposes, e.g. to power irrigation In 1878 Mouchot built a third engine whose boiler systems. consisted of many tubes placed side by side. The Various historical surveys of solar energy experiments have been published [1-3]; not any one of them, reflector area was 5.2 m2. It was tested by two comhowever, has been purposely addressed to the subject of missions appointed by the French government. During a past developments of solar powered irrigation systems. period of 176 days the apparatus distilled 2.7 m3 of water. Therefore, the objective of this paper is to present an The commissions eventually concluded that the device overall picture of the past efforts which have lead to the was too expensive to be employed economically. At about the same time in France, A. P/fre[10-13] also present progress in this field. experimented with concentrating reflectors and boilers. REVIEW OF PAST gFFORTS TO DEVELOP SOLAR POWERED Unlike Mouchot, he used parabolic reflectors rather than SYb~rEMS truncated cones. Pifre demonstrated his sun-power plant The first reported effort to convert solar energy into at the Paris Exposition of 1878; it drove a small steam mechanical power was that of Solomon de Caux (1576- engine which then ran a printing press. In a report 1625), a French engineer [4]. In 1615 he described a published in 1880 he described a 9.3 m z reflector which machine for raising water by the expansion of air from drove a rotary pump raising about 0.I m3 of water in 14 rain against a 3 m pumping head. solar heat. Almost simultaneously with Mouchot and Pifre, The first experiments with solar boilers to generate steam for solar engines using reflectors for concentration numerous experiments were undertaken by the successwere apparently those done by C. GOntner of Laibach, ful engineer and versatile inventor J. Ericsson, a Swedish Austria from 1854 to 1873 [5]. He used a series of long, immigrant to America. He constructed a solar steam narrow mirrors lying parallel to one another on the engine in 1870 using long boiler tubes located at the foci ground, each revolving about its long axis. Each mirror of parabolic troughs. Ericsson declined to give details was tilted so that it reflected the sun onto a long boiler about his boilers for protective reasons, but he stated tube above the mirrors and parallel to them. Linkages that the boiler-reflector arrangement "extracts, on an between the mirrors caused them all to turn simul- average, during 9 hours a day .... fully 40 kJ per min for taneously to follow the sun. He found that 18.6m 2 of each mz of area presented perpendicularly to the sun's mirror surface could generate steam in his system rays." He also experimented with air as a working fluid in his boiler-reflectors, building seven hot-air engines su~cient to produce 1 h.p. A. Mouchot[1, 6-9] did research on solar energy con- between 1872 and 1875. In 1883 Ericsson[l, 14] built a large "sun motor" which version in France from 1860 to 1878. He used a conical INTRODUCTION
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J. T. PY'rLINSrd
was demonstrated in New York. It consisted of a shallow parabolic trough 3.3 m long and 4.9 m wide focusing solar radiation on a 3.5 m diameter boiler tube. Steam from the boiler was fed to a steam engine. The entire apparatus was turned manually to follow the sun. Ericsson disclosed only a few details about the actual performance of the system. He indicated that summer trials allowed operation at a steam pressure of 24 x 104 N/m 2, driving a reciprocating engine at 120rpm. With a concentration ratio of 9 he claimed to generate 1 h.p. per 9.3 m 2 of reflective surface, or about 1.6h.p. total. In 1886 he experimented with a 2.5 h.p. solar engine. From 1876 to 1878 W. Adams[l, 15] in Bombay, India experimented with small plane mirrors arranged to approximate a segment of a spherical surface 12.2m in diameter, focusing the solar radiation on a thick copper boiler. This arrangement is said to have continuously produced steam at a pressure of 20.7 x 104 N/m 2, running a 2.5 h.p. pump for 20 consecutive days. In 1885 an experiment was performed in Auteuil, France during which over 1 m 3 of water was pumped per hour using a solar vapor engine [16]. Sunlight falling on metal rooftop collectors warmed an ammonia solution within them, driving off ammonia vapor. This vapor displaced the water inside a submerged iron sphere thus providing a pumping action. A flexible rubber membrane acted as a bellows, keeping the ammonia physically separated from the water. When the water was pumped out, the ammonia was condensed and recycled, and the cycle began again. The inventor claimed that in a wanner climate this type of solar pump could pump about 3 m 3 of water per hour against a 19.8 m head. An overall view of the installation is shown in Fig. 1.
tube boiler 4 m in length which held 0.38 m 3 of water, leaving 0.20 m3 for steam. The entire boiler and reflector system was mounted on an equatorial axis, automatically clock-driven to follow the sun. The steam at a pressure of 10.3 x 105 N/n~2 drove an 11 h.p. compound condensing engine belted to a centrifugal pump. At a pumping rate of 5.3 m 3 per rain against a 3.6 m head, the system produced a peak power of about I0 h.p. A view of the installation is shown in Fig. 2. Eneas also built another plant at Mesa, Arizona in 1903 which was moved to Tempe in 1904 (see Fig. 3) and subsequently moved to Willcox, and Cochise, in southeastern Arizona. The plant used about 65 m2 of collecting surface to produce steam at a pressure of 10.3x 10~N/m 2. About 2.5x 103kj of solar radiation was collected by every m2 of collectors. From 1902 to 1908 H. Willsie[18] built a number of solar engines. He immersed pipes containing a low temperature working fluid such as ammonia, ether, or sulphur dioxide in shallow, horizontal, double-glazed flatplate collectors filled with water. These fluids were then used to operate engines. A number of systems were under investigation at that time. In 1902 at Olney, Illinois and Hardyville, Arizona flat-plate collectors with double glazing were used to
Fig. 2. Eneas' solar-powered irrigation installation (Pasadena, California, 1901). Fig. 1. Solar-powered water pumping installation (Auteuil. . . . . . . . . . . France, 1885). In the early twentieth century from 1900 to World War I, a number of important solar experiments were undertaken. Among the first were those of A. Eneas in the United States. The most famous of the solar installations built by Eneas was the one erected at the Ostrich Farm in Pasadena, California in 1901 [1]. According to a report published in 1901 [17], the reflector was a truncated cone 10.2 m in diameter with a central opening of 4.6 m in the bottom. The inner surface was composed of 1788 small, flat mirrors arranged to approximate the conical surface. The mirrors reflected solar radiation onto the central
Fig. 3. Eneas' improved solar-powered irrigation installation (Tempe, Arizona, 1904).
Solar energy installations for pumpingirrigation water
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produce modest temperatures. Similar collectors with a total area of about 55.7 m2 were used to operate a 6 h.p. ammonia engine in St. Louis in 1904. A plant built along similar lines using sulphur dioxide as the working fluid was constructed at Needles, California in 1905. Heat from the collectors generated vapor pressures of the working fluid over 13.8× 105N/m 2, corresponding to temperatures above 344°K. This vapor drove a 20 h.p. slide-valve engine which operated a contrifugal pump, a compressor, and two circulating pumps. A second and final plant at Needles built in 1908 used a series of single and double-glazed collectors (total area 9.3m 2) to produce water temperatures of 355°K. The solar engine Fig. 5. Overall view of Shuman's installation (Tacony, Pennsylvania, 1907). attained 15 h.p. at a pressure of 14.8 × 105 N/m2. In the period between 1906 and World War I, F. Shuman built a number of solar engines, some of which this modest performance that a concentration of the were used for pumping irrigation water. In 1907 he used sun's rays would be necessary. In 1911 he accordingly solar energy in Tacony, Pennsylvania to drive a 3.5 h.p. constructed at Tacony, Pennsylvania a series of test vapor engine using ether as the working fluid [19, 20]. A absorbers with side-wing concentration [1, 1%22]. The block diagram of the plant is shown in Fig. 4 and an absorbers were quite similar to those used in 1910-overall view of the plant is shown in Fig. 5. A pond of an lamellar boilers in double-glazed wooden boxes--but had area of 11.2 x 103m 2 covered by glass was used to heat in addition two flat reflecting wings extending above and ether which circulated in a heat exchanger immersed in below at 120° angles. These wings reflected additional the water. Ether vapor generated in this way ran an radiation onto the absorber boxes. Twenty-one collectors engine connected to a small contrifugal pump. with wings were linked together to form a long, troughAckermarm[20] reports, "it is said that the plant worked like bank. Twenty-six such banks were deployed in 13 when the sunshine was bright, even when the at- rows of two banks each with a total collecting area of mospheric temperature was below 273°K.'' 956.5 m2. A 0.2 m diameter steam main ran through the In 1910 Shuman built a second type of absorber; center of the array to convey the steam to the engine. basically a lamellar boiler made of two sheets of copper, The rows were aligned in an east-west direction and each 1.8 m by 0.8 m, separated by a space of 0.05 m. The hence did not have to track the sun, though once a week boiler was enclosed in a wooden box covered with two the angle of elevation was changed to ajust for changes sheets of ordinary window glass; the upper boiler plate in solar declination. was painted black. His objective was to produce In tests made in August 1911, the system pumped saturated steam at a pressure of 10 x 104 N/m 2 and at a 11.3 m3 of water per min to a height of 10 m, equivalent temperature of 473°K. The result was a peak production to a peak power output of 24h.p. The daily average of 0.4 kg of steam during one hour of system operation power output, however, was closer to 16 h.p. An overall on 27 August 1910. The 1000kJ of heat needed to view of the irrigation plant is shown in Fig. 6. produce the steam meant that the absorption rate for this Shuman especially designed the engine used for this small collector was 672 kJ/hm 2. Shuman concluded from plant to run on low-pressure steam at 150rpm [19, 23]. SOLAR RADIATION |
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Fig. 4. Block diagram of Shuman's installation (Tacony,Pennsylvania, 1907).
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J. T. PYrLINSK!
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Fig. 6. Shuman's solar-powered irrigation installation (Tacony, Pennslvania, 1911). The single piston had a diameter of 0.9 m and a stroke of 0.9 m. The Shuman steam engine is shown in Fig. 7. The 1911 installation was followed by a large and important irrigation plant installed by Shuman and Boys in 1913 in Meadi, Egypt[l, 19, 20, 22, 24]. C. Boys, an Englishman invited to be a consultant, suggested important changes in the construction of the solar absorbers. Glass-covered boiler tubes were to be placed along the focusing axis of trough-shaped parabolic cylinders. These changes were adopted, and the original plan to use the 1911 Tacony absorbers was abandoned. In addition, the collectors were placed with their long axes running
Fig. 7. Shuman's low-pressure steam engine (Tacony, Pennsylvania, 1911). SOLAR RADIATION
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north-south and w e r e rotated automatically during the day to follow the east-west motion of the sun. A block diagram of the system is shown in Fig. 8. A concentrator used to generate steam in the ShumanBoys irrigation plant is shown in Fig. 9 [20]. Each parabolic concentrator (five in total) was 62.5 m long and 4m wide, providing a total solar radiation collecting surface of 1280.8m2. The concentration ratio of 4.6 resulted in an overall peak absorber efficiency of 40.7 per cent. The plant developed up to 73 brake h.p. An overall view of the plant is shown in Fig. 10. Less known but not less significant is the work done on solar devices by R. H. Goddard. Between 1919 and 1934 he published several papers and took out many patents related to the use of solar energy as a power
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Fig. 9. Shuman and Boys parabolic collector (Meadi, Egypt, 1913).
Fig. 10. Overall view of Shuman and Boys solar-powered irrigation installation (Meadi, Egypt, 1913).
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c°gEN"I Fig. 8. Block diagram of Shuman and Boys solar-poweredirrigation installation (Meadi, Egypt, 1913).
Solar energyinstallations for pumping irrigation water source. Although he is better known for his research on rockets, Goddard's contribution to the development of solar energy as a power source deserves to be recognixed. In 1919 he described the first large-scale solar electric power plant (see Fig. 11) [25, 26]. In the same paper he stated that "...the size illustrated would produce upwards of thirty useful horsepower when operating under a clear sky between the hours of ten in the morning and three in the afternoon--the time when sunlight is at its maximum power in the United States. The amount of power, converted into electrical energy, would far exceed the requirements of a large farm; the unused current could be employed to charge batteries. These in turn could maintain the normal current supply of cloudy days and at night." A similar system was proposed by Honeywell to be used for pumping irrigation water [27].
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From 1951 to 1955 N. Ghai and M. Khanna[32] worked on devoloping high-temperature hot-air engines with heat supplied from concentrating parabolic solar reflectors. One small engine (between 0.125 and 0.166 h.p.) operated at temperatures ranging from 644 to 922°K and pumped water from a depth of approximately 4.8 m. These engines were similar to the open-cycle hot-air engines used by Ericsson. In 1961 T. Finelstein[33] described a Stirling-cycle engine with a quartz window which allowed direct radiative heating by concentrating solar radiation. Various types of hot-air engines have been built and operated with success by E. Farber [34, 35]. H. Tabor built a 5 h.p. solar installation for pumping water in 1961. The system used a binary Rankine cycle with monochlorobenzine (C6HsCI) vaporized by superheated steam from solar collectors. The vapors ran through a turbine to generate mechanical power. The National Physical Laboratory of Israel commercially developed this concept and produced what are known as ORMAT Rankine Power Units [36, 37]. Power units of this type are currently available, ranging from a few hundred W to 15 kW. Such a solar irrigation plant used for pumping water in 1967 in Mali, Africa is shown in Fig. 12 [38]. The plant lifted 11.3 m3 of water per day from a 45.7 m well.
Fig. 11. Goddard's solar-poweredplant (1919). Around 1920 in New Mexico, J. Harrington[28] focused sunlight into a boiler to run a steam engine that pumped water up 6 m into a tank with a capacity of 18.9m 3. The elevated water powered a water turbinedriven generator. In 1936 C. Abbot[29, 30] converted solar energy into mechanical power via 0.5 h.p. steam engine. The author claimed an overall system efficiency of 15.5 per cent. Solar radiation was intercepted by a parabolic trough reflector whose focal axis was mounted parallel to the earth's axis of rotation to produce the familiar equatorial mounting used by astronomers. Along the focal axis was a single tube flash-boiler encased in a long, double-walled evacuated glass sleeve to reduce heat losses. Water was fed to the boiler automatically. The system was designed to raise full steam pressure within five minutes of exposure to the sun's rays, producing saturated steam at 6470K. From 1941 to 1946 F. Molero[31] of the Soviet Union used large, 10m diameter parabolic dish reflectors to produce steam at a pressure of 20.3 x l04 N/m 2 for solar engines.
Fig. 12. ORMAT solar-powered irrigation installation (Mali, Africa, 1967). In Dakar, Senegal from 1962 to 1966, H. Masson and J. Girardier[39] operated a small solar engine which pumped 7.9-9.8 ma of water per min from a depth of 13 m, using a collection area of 6 m2. The operation of this prototype led to the design and construction of a larger, more efficient pump. This new installation, with a collection area of 300m2, was capable of pumping 37.8 m3 of water. The water was used to vaporize a secondary fluid which expanded through a turbine to generate electricity. The electricity in turn drove the pump via an electric motor. The first solar system to use concentrated solar radiation on photovoltaic cells to generate electricity for pumping water was installed and tested near Gelendzhik in the Soviet Union in September 1964 [40]. The system developed a maximum electric power of 0.25kW, obtained for a nominal value of solar radiation of 198 x 103kJ/hm2. The silicon photovoltaic cells of a total area of 3.6m 2 were mounted on three panels 5 x I m each which could rotate equatorially. The panels were equip-
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J. T. PYTLINSKI
ped with flat-plate concentrating mirrors assuring a 2.5 concentration ratio. Natural air convection cooled the photovoltaic cells. The system had an energy conversion efficiency of 2.6 per cent. Figure 13 shows an overall view of the installation.
working fluid (Refrigerant 11). A vapor turbine and an electric generator produce 30 kW of electric power which drives two pumps. The station supplies about 1000m5 of potable water per day to the neighboring community of San Luis de la Paz. An overall view of the installation is shown in Fig. 15. Systems capable of producing 25 kW and 50kW power output are also available from SOFRETES [45].
Fig. 13. Solar-poweredwater pumping systemusing photovoltaic concentrator (Gelendzhik, Soviet Union, 1964).
Fig. 15. SOFRETES solar-pewered water pumping installation (Guanajuato, Mexico, 1976).
The generation of steam at high temperatures and pressures using heliostats and special multicellular solar radiation receivers was achieved in Italy. One such solar plant built by G. Francia[41] in 1965 at St. Ilario-Nervi, Genoa produced 18.9 kg/h of steam at 152 x 105 N/m 2 pressure and 773°K average temperature for a 5-6 hr period. The collector area was 30 m2. Francia increased the collector surface in 1966 which resulted in a doubling of the average output of steam from 18.9kg/h to 37.8 kg/h at apressure of 152 x l0s NIm2 and temperature of 773°K. A view of Francia's first solar power plant built in 1965 is shown in Fig. 14. The last power plant built by Francia in 1968 used 200 m2 of heliostats area producing 149.7kg of steam per hr at 152 x 105 N/m2 pressure and 82YK temperature. The bell-shaped boiler of 0.91m diameter was about 0.9 m high and absorbed 95 per cent incident solar energy. Although the plant has not yet been used to pump water, this type of system is now being investigated for this purpose [42, 43]. A solar water pumping station built by the French company SOFRETES began operation in Guanajuato, Mexico in 1976 [44]. The installation employs 2499 m2 of flat-plate collectors. Water is used as the primary heat transfer fluid. The heat is transferred from water to the
In April 1977 a large installation for pumping irrigation water was put into operation on Gila River Ranch near Phoenix, Arizona [46]. The system is equipped with parabolic tracking collectors having a total area of 564 m2. The collector design efficiency was 55 per cent while the actual field efficiency is 44-50 per cent. The installation's Rankine-cycle power unit consisting of a radial-inflow turbine/gearbox, boiler, condenser, regenerator and preheater is capable of developing a 50h.p. power output and of pumping about 38 m3 of irrigation water per rain at peak operation. Water heated to 42TK is used as the primary heat transfer fluid. Refrigerant 113 is used as the working fluid. The radialinflow turbine develops 30,500 rpm which is reduced by a gearbox to an output shaft speed of 1760rpm. An overall view of the system installed on about 1012m2 of land is shown in Fig. 16 [47,48]. A solar powered irrigation plant near Willard, New Mexico began operation in June 1977 (see Fig. 17) [4953, 55]. Parabolic trough collectors oriented north-south with a total area of 622.4 m2 are used to provide energy for immediate operation and for storage. The Rankine cycle operates at a peak temperature of 436°K of the secondary fluid (Refrigerant 113) and at a temperature of
Fig. 14. Francia's solar-poweredplant (Genoa, Italy, 1965).
Fig, 16. Battelle Memorial Institute built solar-powered water pumping installation (Gila Bend, Arizona, 1977).
Solar energy installations for pumpingirrigation water
Fig. 17. Sandia Laboratories built solar-powered pumping installation (Willard, New Mexico, 1977). 4890K of the primary fluid (Caloria HT-43). Caloria HT43 is also used as the heat storage fluid in a 22.7 m3 tank. A specially built vapor turbine runs at 36,300rpm developing 1760rpm at the output shaft of the gearbox. Other system elements such as valves, fittings, heat exchangers, etc. are off-the-shelf units. The system develops 25 h.p. with a Rankine cycle efficiency of 15 per cent. The water output of 2.6 m3 per rain from a 34 m deep well can provide irrigation for up to 404.6 m2 of land. A schematic diagram of the system is shown in Fig. 18
[52].
Figure 19 shows the firstlarge-scaleuse of photovoltaic cells t~.generate electricityfor pumping irrigation water near Mead, Nebraska [54,55].Put intooperationin August 1977, the installation'spurpose at this stage is basically experimental.The electricsystem consists of 120,000 individualsilicontype photovoltaiccellsmounted on 28 flatpanels arranged in two rows. Each row can develop a peak power ofabout 25kW. Lead acid batterieswith a totalcapacity of 85 kWh provide about 6hr of energy storage. Inverters are used to convert direct current electricityproduced by cellsand batteries into alternatingcurrent to power the irrigationpump
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Fig. 19. MIT's Lincoln Laboratorybuilt solar-poweredirrigation water pumping installation using photovoltaic cells (Mead, Nebraska, 1977). motor. A 10 h.p. motor runs 12 hr a day pumping 3.8 m3 of water per min out of a reservoir. The water is distributed through an automatic-gated pipe irrigation system. CONCLUSIONS The devices and installations presented here, used to generate mechanical power and/or to pump irrigation water with the aid of solar energy, represent a significant cross section of the past developments in this field. It is apparent that most efforts were directed toward developing more efficient, higher power output, lower cost devices and conversion systems by using the technology available at the time. Many concepts and ideas introduced during recent years follow in general past developments in applying contemporary technology and new materials. However, energy storage, low-use factor of solar irrigation systems and the high cost of such systems still need to be solved. The use of photovoltaic cells in an all electric system or in a hybrid system appears to be an almost ideal solar energy application for pumping irrigation water; if problems related to power conditioning can be eliminated, and if the cost of these systems can be decreased.
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Fig. 18. Schematicdiagram of Sandia Laboratoriesbuilt system.
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J.T. PYI"LINSKI REFERENCES
1. A. S. E. Ackermann, Z Roy. Soc. Arts, 538-565 (1915). 2. H. Heywood, Engineering, 176 (1953). 3. R. C. Jordan and W. E. Ibele, Proc. World Syrup. Appl. Solar Energy, Phoenix, Arizona (1955). 4. S. de Caux, The Cause of Motive Power, E. I. Norton, Frankfurt, Germany (1615). 5. C. Giintner, Scientific American Supplement, Vol. 61, pp. 25409-25412 (1906). 6. A. B. Mouchot, La Chaleur Solaire et les Applications lndustrieUes, Ed. Gauther-Villars,Paris, France (1869). 7. A. B. Mouchot, Comptes Rendus de l'Acad~mie des Sciences (Paris), France $1, 74 (1875). 8. A. B. Mouchot, Comptes Rendus de I'Acad~mie des Sciences (Paris), France 86, 132 (1878). 9. A. B. Mouchot, Comptes Rendus de l'Acad~mie des Sciences (Paris), France 87, 481 (1878). 10. A. Pifre, Le G~nie Civil 7, 797 (1878). 11. A. Pifre, Revue Scientific $, 15 (1883). 12. A. Pifre, Nature 26, 503-504 (1882). 13. S. P. Langley, The New Astronomy, pp. 91-116, Houghton, Mi~lin, New York (1896). 14. J. Ericsson, Nature 29, 217 (1884). 15. W. Adams, Scientific American 38-39, 376 (1878). 16. Editorial Article, Scientific American 53, 214 (1885). 17. C. F. Holder, Scientific American 84, 169 (1901). 18. H. R. Willsie, Engng News 61(19), 511 (1909). 19. G. Hally, Institution of Engineers and Shipbuilders in Scotland, Trans, Vol. 57, p. 347 (1913--14). 20. A. S. E. Ackermarm, The Society of Engineers, London. Trans. Vol. 103, p. 81 (1914). 21. Editorial Article, Engng News 66(12), 327 (1911). 22. A. D. Blake, Power 34, 506 (1911). 23. Editorial Article, Scientific American Supplement 76, 29 (1913). 24. Editorial Article, Scientific American 109, 334 (1913). 25. R. H. Goddard, Popular Science Monthly 115, 22-23, 157 (1929). 26. E. R. I-Iagemann,Solar Energy 6(1), 47 0962). 27. Preliminary Design Study for a 150 kW Solar-Powered Deep Well Irrigation Facility, Vol. I, Technical Proposal, November 1976, Honeywell, Energy Resources Center, Minneapolis,Minnesota. 28. F. Daniels, The Direct Use of Sun's Energy, p. 13, Bailantine Books, New York (1964). 29. C. G. Abbot, Smithsonian Miscellaneous Collections 98(5), 1 (1939). 30. C. G. Abbot, Ann. Rep. Smithsonian Inst. p. 99 (1943).
31. M. V. Kirpithev and V. A. Baum, Priroda (in Russian), p. 45 (1954). 32. K. N. Mathur and M. L. Khanna, Add Zone Programme Symposium on Solar Energy and Wind Power in the Add Zones, New Delhi, India, October (1954). 33. T. Findelstein, Am. SOc. Mech. Engrs, Paper 61-WA-287, Annual Meeting (1961). 34. E. A. Farber and F. L. Prescott, Solar Energy 9(3), 170 (1965). 35. E. A. Farber and F. L. Prescott, Solar Energy 9(3), 175 0965). 36. J. I. Yellot,Z Engng/or Power 84, 213 (1962). 37. L. Y. Bronicki, Proc. 7fh Intersoc:Energy Conversion Con/., San Diego, California,Paper 729057, p. 327 (1972). 38. EditorialArticle,Solar Energy Digest 5(5), I (1975). 39. H. Masson and J. P. Girardier,Solar Energy 10(4),165 (1966). 40. V. A. Baum, Semiconductor Solar Energy Converters,p. 37, Consultants Bureau, New York (1969). 41. G. Francia, Solar Energy 12, 51 (1968). 42. J. T. Pytlinski and N. D. Eckhoff, Proc. Int. Conf. Alt. Energy Sources, Vol. 3, Chap. 9, Miami Beach, Florida, 5-7 December (1977). 43. S. L. Levy, Solar Irrigation Workshop (Proc.), p. 44, Albuquerque, New Mexico (7-8 July 1977). 44. J. Anderson, Critical Mass. 2(2), 14 (1976). 45. W. J. Bornhorst, Thermo Electron Co., Watham, Mass.; private communication(1977). 46. G. M. McClure, Solar Irrigation Workshop (Proc.), p. 28, Albuquerque, New Mexico (7-8 July 1977). 47. J. C. McKeon, The Northwestern Mutual Life Insurance Company, Milwaukee, Wisconsin; private communication (1978). 48. G. Talbert, et al. The development of a 37 kW solar-powered irrigation system. Int. Solar Energy SOc. Meet., New Delhi, India (16-29 January 1978). 49. Sandia Science News 12(4), 3, Sandia Laboratories, Albuquerque, New Mexico (1977). 50. R. E. Barber, Solar Irrigation Workshop (Proc.), p. 38, Albuquerque, New Mexico (7-8 July 1977). 51. G. H. Abernathy, New Mexico State University, Las Cruces, New Mexico; private communication (1977). 52. G. H. Abemathy and T. R. Mancini, Am. SOc. Agr. Eng., Paper No. 77-4020, Annual Meeting Raleigh, North Carolina (26-29 June 1977). 53. G. H. Abemathy and T. R. Mancini, Agr. Engng 58(10), 39 (1977). 54. D. Morris, Smithsonian 8(7), 38 (1977). 55. G. L. Smith, Kansas Farmer, p. D. (3 September 1977).
0038--092~8/1001-0255/$05.00/0
REVIEW PAPER
SOLAR ENERGY INSTALLATIONS FOR PUMPING IRRIGATION WATER J. T. PYTLINSKI New Mexico Solar EnergyInstitute, New Mexico State University, Las Cruces NM 88003, U.S.A. (Received 5 October 1977;revision accepted 8 May 1978)
mirror (45° cones) to focus solar radiation on a copper Solar radiation reaching the surface of the earth is in- boiler located along the axis of the cone. The boiler was termittent due to atmospheric conditions and the rotation blackened to enhance absorptivity and covered with glass to reduce heat losses. The entire apparatus could be of the earth. This intermittence and variability inherently limit the useful conversion of solar radiation by requiring swiveled by hand to follow the sun. Mouchot demonstrated his first solar engine in Paris in either intermediate storage of energy or application to a 1866. He constructed a second engine in 1875 with task where intermittency is acceptable. The pumping of irrigation water is an operation where financial assistance from the French government. This normally intermittent operation may be acceptable. This engine had a reflecting surface area of 4 m z and an axial fact, plus the potential economical benefits to be boiler 0.8 m long. It produced steam at 50.7 x 10' N/m 2 obtained, has ingigated the research in this area. And and 426°K. The pressure was reduced to 20.3 x 104N/m 2 since this problem is basically that of converting solar and the steam was used to operate a small reciprocating radiation to mechanical energy, it is very much related to engine at 80 strokes per min. Later it was used to power past efforts to develop "solar engines" which might be a rotary engine driving a water pump. The inventor claimed a power of 0.5 h.p. used for a number of purposes, e.g. to power irrigation In 1878 Mouchot built a third engine whose boiler systems. consisted of many tubes placed side by side. The Various historical surveys of solar energy experiments have been published [1-3]; not any one of them, reflector area was 5.2 m2. It was tested by two comhowever, has been purposely addressed to the subject of missions appointed by the French government. During a past developments of solar powered irrigation systems. period of 176 days the apparatus distilled 2.7 m3 of water. Therefore, the objective of this paper is to present an The commissions eventually concluded that the device overall picture of the past efforts which have lead to the was too expensive to be employed economically. At about the same time in France, A. P/fre[10-13] also present progress in this field. experimented with concentrating reflectors and boilers. REVIEW OF PAST gFFORTS TO DEVELOP SOLAR POWERED Unlike Mouchot, he used parabolic reflectors rather than SYb~rEMS truncated cones. Pifre demonstrated his sun-power plant The first reported effort to convert solar energy into at the Paris Exposition of 1878; it drove a small steam mechanical power was that of Solomon de Caux (1576- engine which then ran a printing press. In a report 1625), a French engineer [4]. In 1615 he described a published in 1880 he described a 9.3 m z reflector which machine for raising water by the expansion of air from drove a rotary pump raising about 0.I m3 of water in 14 rain against a 3 m pumping head. solar heat. Almost simultaneously with Mouchot and Pifre, The first experiments with solar boilers to generate steam for solar engines using reflectors for concentration numerous experiments were undertaken by the successwere apparently those done by C. GOntner of Laibach, ful engineer and versatile inventor J. Ericsson, a Swedish Austria from 1854 to 1873 [5]. He used a series of long, immigrant to America. He constructed a solar steam narrow mirrors lying parallel to one another on the engine in 1870 using long boiler tubes located at the foci ground, each revolving about its long axis. Each mirror of parabolic troughs. Ericsson declined to give details was tilted so that it reflected the sun onto a long boiler about his boilers for protective reasons, but he stated tube above the mirrors and parallel to them. Linkages that the boiler-reflector arrangement "extracts, on an between the mirrors caused them all to turn simul- average, during 9 hours a day .... fully 40 kJ per min for taneously to follow the sun. He found that 18.6m 2 of each mz of area presented perpendicularly to the sun's mirror surface could generate steam in his system rays." He also experimented with air as a working fluid in his boiler-reflectors, building seven hot-air engines su~cient to produce 1 h.p. A. Mouchot[1, 6-9] did research on solar energy con- between 1872 and 1875. In 1883 Ericsson[l, 14] built a large "sun motor" which version in France from 1860 to 1878. He used a conical INTRODUCTION
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was demonstrated in New York. It consisted of a shallow parabolic trough 3.3 m long and 4.9 m wide focusing solar radiation on a 3.5 m diameter boiler tube. Steam from the boiler was fed to a steam engine. The entire apparatus was turned manually to follow the sun. Ericsson disclosed only a few details about the actual performance of the system. He indicated that summer trials allowed operation at a steam pressure of 24 x 104 N/m 2, driving a reciprocating engine at 120rpm. With a concentration ratio of 9 he claimed to generate 1 h.p. per 9.3 m 2 of reflective surface, or about 1.6h.p. total. In 1886 he experimented with a 2.5 h.p. solar engine. From 1876 to 1878 W. Adams[l, 15] in Bombay, India experimented with small plane mirrors arranged to approximate a segment of a spherical surface 12.2m in diameter, focusing the solar radiation on a thick copper boiler. This arrangement is said to have continuously produced steam at a pressure of 20.7 x 104 N/m 2, running a 2.5 h.p. pump for 20 consecutive days. In 1885 an experiment was performed in Auteuil, France during which over 1 m 3 of water was pumped per hour using a solar vapor engine [16]. Sunlight falling on metal rooftop collectors warmed an ammonia solution within them, driving off ammonia vapor. This vapor displaced the water inside a submerged iron sphere thus providing a pumping action. A flexible rubber membrane acted as a bellows, keeping the ammonia physically separated from the water. When the water was pumped out, the ammonia was condensed and recycled, and the cycle began again. The inventor claimed that in a wanner climate this type of solar pump could pump about 3 m 3 of water per hour against a 19.8 m head. An overall view of the installation is shown in Fig. 1.
tube boiler 4 m in length which held 0.38 m 3 of water, leaving 0.20 m3 for steam. The entire boiler and reflector system was mounted on an equatorial axis, automatically clock-driven to follow the sun. The steam at a pressure of 10.3 x 105 N/n~2 drove an 11 h.p. compound condensing engine belted to a centrifugal pump. At a pumping rate of 5.3 m 3 per rain against a 3.6 m head, the system produced a peak power of about I0 h.p. A view of the installation is shown in Fig. 2. Eneas also built another plant at Mesa, Arizona in 1903 which was moved to Tempe in 1904 (see Fig. 3) and subsequently moved to Willcox, and Cochise, in southeastern Arizona. The plant used about 65 m2 of collecting surface to produce steam at a pressure of 10.3x 10~N/m 2. About 2.5x 103kj of solar radiation was collected by every m2 of collectors. From 1902 to 1908 H. Willsie[18] built a number of solar engines. He immersed pipes containing a low temperature working fluid such as ammonia, ether, or sulphur dioxide in shallow, horizontal, double-glazed flatplate collectors filled with water. These fluids were then used to operate engines. A number of systems were under investigation at that time. In 1902 at Olney, Illinois and Hardyville, Arizona flat-plate collectors with double glazing were used to
Fig. 2. Eneas' solar-powered irrigation installation (Pasadena, California, 1901). Fig. 1. Solar-powered water pumping installation (Auteuil. . . . . . . . . . . France, 1885). In the early twentieth century from 1900 to World War I, a number of important solar experiments were undertaken. Among the first were those of A. Eneas in the United States. The most famous of the solar installations built by Eneas was the one erected at the Ostrich Farm in Pasadena, California in 1901 [1]. According to a report published in 1901 [17], the reflector was a truncated cone 10.2 m in diameter with a central opening of 4.6 m in the bottom. The inner surface was composed of 1788 small, flat mirrors arranged to approximate the conical surface. The mirrors reflected solar radiation onto the central
Fig. 3. Eneas' improved solar-powered irrigation installation (Tempe, Arizona, 1904).
Solar energy installations for pumpingirrigation water
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produce modest temperatures. Similar collectors with a total area of about 55.7 m2 were used to operate a 6 h.p. ammonia engine in St. Louis in 1904. A plant built along similar lines using sulphur dioxide as the working fluid was constructed at Needles, California in 1905. Heat from the collectors generated vapor pressures of the working fluid over 13.8× 105N/m 2, corresponding to temperatures above 344°K. This vapor drove a 20 h.p. slide-valve engine which operated a contrifugal pump, a compressor, and two circulating pumps. A second and final plant at Needles built in 1908 used a series of single and double-glazed collectors (total area 9.3m 2) to produce water temperatures of 355°K. The solar engine Fig. 5. Overall view of Shuman's installation (Tacony, Pennsylvania, 1907). attained 15 h.p. at a pressure of 14.8 × 105 N/m2. In the period between 1906 and World War I, F. Shuman built a number of solar engines, some of which this modest performance that a concentration of the were used for pumping irrigation water. In 1907 he used sun's rays would be necessary. In 1911 he accordingly solar energy in Tacony, Pennsylvania to drive a 3.5 h.p. constructed at Tacony, Pennsylvania a series of test vapor engine using ether as the working fluid [19, 20]. A absorbers with side-wing concentration [1, 1%22]. The block diagram of the plant is shown in Fig. 4 and an absorbers were quite similar to those used in 1910-overall view of the plant is shown in Fig. 5. A pond of an lamellar boilers in double-glazed wooden boxes--but had area of 11.2 x 103m 2 covered by glass was used to heat in addition two flat reflecting wings extending above and ether which circulated in a heat exchanger immersed in below at 120° angles. These wings reflected additional the water. Ether vapor generated in this way ran an radiation onto the absorber boxes. Twenty-one collectors engine connected to a small contrifugal pump. with wings were linked together to form a long, troughAckermarm[20] reports, "it is said that the plant worked like bank. Twenty-six such banks were deployed in 13 when the sunshine was bright, even when the at- rows of two banks each with a total collecting area of mospheric temperature was below 273°K.'' 956.5 m2. A 0.2 m diameter steam main ran through the In 1910 Shuman built a second type of absorber; center of the array to convey the steam to the engine. basically a lamellar boiler made of two sheets of copper, The rows were aligned in an east-west direction and each 1.8 m by 0.8 m, separated by a space of 0.05 m. The hence did not have to track the sun, though once a week boiler was enclosed in a wooden box covered with two the angle of elevation was changed to ajust for changes sheets of ordinary window glass; the upper boiler plate in solar declination. was painted black. His objective was to produce In tests made in August 1911, the system pumped saturated steam at a pressure of 10 x 104 N/m 2 and at a 11.3 m3 of water per min to a height of 10 m, equivalent temperature of 473°K. The result was a peak production to a peak power output of 24h.p. The daily average of 0.4 kg of steam during one hour of system operation power output, however, was closer to 16 h.p. An overall on 27 August 1910. The 1000kJ of heat needed to view of the irrigation plant is shown in Fig. 6. produce the steam meant that the absorption rate for this Shuman especially designed the engine used for this small collector was 672 kJ/hm 2. Shuman concluded from plant to run on low-pressure steam at 150rpm [19, 23]. SOLAR RADIATION |
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Fig. 4. Block diagram of Shuman's installation (Tacony,Pennsylvania, 1907).
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J. T. PYrLINSK!
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Fig. 6. Shuman's solar-powered irrigation installation (Tacony, Pennslvania, 1911). The single piston had a diameter of 0.9 m and a stroke of 0.9 m. The Shuman steam engine is shown in Fig. 7. The 1911 installation was followed by a large and important irrigation plant installed by Shuman and Boys in 1913 in Meadi, Egypt[l, 19, 20, 22, 24]. C. Boys, an Englishman invited to be a consultant, suggested important changes in the construction of the solar absorbers. Glass-covered boiler tubes were to be placed along the focusing axis of trough-shaped parabolic cylinders. These changes were adopted, and the original plan to use the 1911 Tacony absorbers was abandoned. In addition, the collectors were placed with their long axes running
Fig. 7. Shuman's low-pressure steam engine (Tacony, Pennsylvania, 1911). SOLAR RADIATION
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north-south and w e r e rotated automatically during the day to follow the east-west motion of the sun. A block diagram of the system is shown in Fig. 8. A concentrator used to generate steam in the ShumanBoys irrigation plant is shown in Fig. 9 [20]. Each parabolic concentrator (five in total) was 62.5 m long and 4m wide, providing a total solar radiation collecting surface of 1280.8m2. The concentration ratio of 4.6 resulted in an overall peak absorber efficiency of 40.7 per cent. The plant developed up to 73 brake h.p. An overall view of the plant is shown in Fig. 10. Less known but not less significant is the work done on solar devices by R. H. Goddard. Between 1919 and 1934 he published several papers and took out many patents related to the use of solar energy as a power
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Fig. 9. Shuman and Boys parabolic collector (Meadi, Egypt, 1913).
Fig. 10. Overall view of Shuman and Boys solar-powered irrigation installation (Meadi, Egypt, 1913).
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c°gEN"I Fig. 8. Block diagram of Shuman and Boys solar-poweredirrigation installation (Meadi, Egypt, 1913).
Solar energyinstallations for pumping irrigation water source. Although he is better known for his research on rockets, Goddard's contribution to the development of solar energy as a power source deserves to be recognixed. In 1919 he described the first large-scale solar electric power plant (see Fig. 11) [25, 26]. In the same paper he stated that "...the size illustrated would produce upwards of thirty useful horsepower when operating under a clear sky between the hours of ten in the morning and three in the afternoon--the time when sunlight is at its maximum power in the United States. The amount of power, converted into electrical energy, would far exceed the requirements of a large farm; the unused current could be employed to charge batteries. These in turn could maintain the normal current supply of cloudy days and at night." A similar system was proposed by Honeywell to be used for pumping irrigation water [27].
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From 1951 to 1955 N. Ghai and M. Khanna[32] worked on devoloping high-temperature hot-air engines with heat supplied from concentrating parabolic solar reflectors. One small engine (between 0.125 and 0.166 h.p.) operated at temperatures ranging from 644 to 922°K and pumped water from a depth of approximately 4.8 m. These engines were similar to the open-cycle hot-air engines used by Ericsson. In 1961 T. Finelstein[33] described a Stirling-cycle engine with a quartz window which allowed direct radiative heating by concentrating solar radiation. Various types of hot-air engines have been built and operated with success by E. Farber [34, 35]. H. Tabor built a 5 h.p. solar installation for pumping water in 1961. The system used a binary Rankine cycle with monochlorobenzine (C6HsCI) vaporized by superheated steam from solar collectors. The vapors ran through a turbine to generate mechanical power. The National Physical Laboratory of Israel commercially developed this concept and produced what are known as ORMAT Rankine Power Units [36, 37]. Power units of this type are currently available, ranging from a few hundred W to 15 kW. Such a solar irrigation plant used for pumping water in 1967 in Mali, Africa is shown in Fig. 12 [38]. The plant lifted 11.3 m3 of water per day from a 45.7 m well.
Fig. 11. Goddard's solar-poweredplant (1919). Around 1920 in New Mexico, J. Harrington[28] focused sunlight into a boiler to run a steam engine that pumped water up 6 m into a tank with a capacity of 18.9m 3. The elevated water powered a water turbinedriven generator. In 1936 C. Abbot[29, 30] converted solar energy into mechanical power via 0.5 h.p. steam engine. The author claimed an overall system efficiency of 15.5 per cent. Solar radiation was intercepted by a parabolic trough reflector whose focal axis was mounted parallel to the earth's axis of rotation to produce the familiar equatorial mounting used by astronomers. Along the focal axis was a single tube flash-boiler encased in a long, double-walled evacuated glass sleeve to reduce heat losses. Water was fed to the boiler automatically. The system was designed to raise full steam pressure within five minutes of exposure to the sun's rays, producing saturated steam at 6470K. From 1941 to 1946 F. Molero[31] of the Soviet Union used large, 10m diameter parabolic dish reflectors to produce steam at a pressure of 20.3 x l04 N/m 2 for solar engines.
Fig. 12. ORMAT solar-powered irrigation installation (Mali, Africa, 1967). In Dakar, Senegal from 1962 to 1966, H. Masson and J. Girardier[39] operated a small solar engine which pumped 7.9-9.8 ma of water per min from a depth of 13 m, using a collection area of 6 m2. The operation of this prototype led to the design and construction of a larger, more efficient pump. This new installation, with a collection area of 300m2, was capable of pumping 37.8 m3 of water. The water was used to vaporize a secondary fluid which expanded through a turbine to generate electricity. The electricity in turn drove the pump via an electric motor. The first solar system to use concentrated solar radiation on photovoltaic cells to generate electricity for pumping water was installed and tested near Gelendzhik in the Soviet Union in September 1964 [40]. The system developed a maximum electric power of 0.25kW, obtained for a nominal value of solar radiation of 198 x 103kJ/hm2. The silicon photovoltaic cells of a total area of 3.6m 2 were mounted on three panels 5 x I m each which could rotate equatorially. The panels were equip-
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ped with flat-plate concentrating mirrors assuring a 2.5 concentration ratio. Natural air convection cooled the photovoltaic cells. The system had an energy conversion efficiency of 2.6 per cent. Figure 13 shows an overall view of the installation.
working fluid (Refrigerant 11). A vapor turbine and an electric generator produce 30 kW of electric power which drives two pumps. The station supplies about 1000m5 of potable water per day to the neighboring community of San Luis de la Paz. An overall view of the installation is shown in Fig. 15. Systems capable of producing 25 kW and 50kW power output are also available from SOFRETES [45].
Fig. 13. Solar-poweredwater pumping systemusing photovoltaic concentrator (Gelendzhik, Soviet Union, 1964).
Fig. 15. SOFRETES solar-pewered water pumping installation (Guanajuato, Mexico, 1976).
The generation of steam at high temperatures and pressures using heliostats and special multicellular solar radiation receivers was achieved in Italy. One such solar plant built by G. Francia[41] in 1965 at St. Ilario-Nervi, Genoa produced 18.9 kg/h of steam at 152 x 105 N/m 2 pressure and 773°K average temperature for a 5-6 hr period. The collector area was 30 m2. Francia increased the collector surface in 1966 which resulted in a doubling of the average output of steam from 18.9kg/h to 37.8 kg/h at apressure of 152 x l0s NIm2 and temperature of 773°K. A view of Francia's first solar power plant built in 1965 is shown in Fig. 14. The last power plant built by Francia in 1968 used 200 m2 of heliostats area producing 149.7kg of steam per hr at 152 x 105 N/m2 pressure and 82YK temperature. The bell-shaped boiler of 0.91m diameter was about 0.9 m high and absorbed 95 per cent incident solar energy. Although the plant has not yet been used to pump water, this type of system is now being investigated for this purpose [42, 43]. A solar water pumping station built by the French company SOFRETES began operation in Guanajuato, Mexico in 1976 [44]. The installation employs 2499 m2 of flat-plate collectors. Water is used as the primary heat transfer fluid. The heat is transferred from water to the
In April 1977 a large installation for pumping irrigation water was put into operation on Gila River Ranch near Phoenix, Arizona [46]. The system is equipped with parabolic tracking collectors having a total area of 564 m2. The collector design efficiency was 55 per cent while the actual field efficiency is 44-50 per cent. The installation's Rankine-cycle power unit consisting of a radial-inflow turbine/gearbox, boiler, condenser, regenerator and preheater is capable of developing a 50h.p. power output and of pumping about 38 m3 of irrigation water per rain at peak operation. Water heated to 42TK is used as the primary heat transfer fluid. Refrigerant 113 is used as the working fluid. The radialinflow turbine develops 30,500 rpm which is reduced by a gearbox to an output shaft speed of 1760rpm. An overall view of the system installed on about 1012m2 of land is shown in Fig. 16 [47,48]. A solar powered irrigation plant near Willard, New Mexico began operation in June 1977 (see Fig. 17) [4953, 55]. Parabolic trough collectors oriented north-south with a total area of 622.4 m2 are used to provide energy for immediate operation and for storage. The Rankine cycle operates at a peak temperature of 436°K of the secondary fluid (Refrigerant 113) and at a temperature of
Fig. 14. Francia's solar-poweredplant (Genoa, Italy, 1965).
Fig, 16. Battelle Memorial Institute built solar-powered water pumping installation (Gila Bend, Arizona, 1977).
Solar energy installations for pumpingirrigation water
Fig. 17. Sandia Laboratories built solar-powered pumping installation (Willard, New Mexico, 1977). 4890K of the primary fluid (Caloria HT-43). Caloria HT43 is also used as the heat storage fluid in a 22.7 m3 tank. A specially built vapor turbine runs at 36,300rpm developing 1760rpm at the output shaft of the gearbox. Other system elements such as valves, fittings, heat exchangers, etc. are off-the-shelf units. The system develops 25 h.p. with a Rankine cycle efficiency of 15 per cent. The water output of 2.6 m3 per rain from a 34 m deep well can provide irrigation for up to 404.6 m2 of land. A schematic diagram of the system is shown in Fig. 18
[52].
Figure 19 shows the firstlarge-scaleuse of photovoltaic cells t~.generate electricityfor pumping irrigation water near Mead, Nebraska [54,55].Put intooperationin August 1977, the installation'spurpose at this stage is basically experimental.The electricsystem consists of 120,000 individualsilicontype photovoltaiccellsmounted on 28 flatpanels arranged in two rows. Each row can develop a peak power ofabout 25kW. Lead acid batterieswith a totalcapacity of 85 kWh provide about 6hr of energy storage. Inverters are used to convert direct current electricityproduced by cellsand batteries into alternatingcurrent to power the irrigationpump
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Fig. 19. MIT's Lincoln Laboratorybuilt solar-poweredirrigation water pumping installation using photovoltaic cells (Mead, Nebraska, 1977). motor. A 10 h.p. motor runs 12 hr a day pumping 3.8 m3 of water per min out of a reservoir. The water is distributed through an automatic-gated pipe irrigation system. CONCLUSIONS The devices and installations presented here, used to generate mechanical power and/or to pump irrigation water with the aid of solar energy, represent a significant cross section of the past developments in this field. It is apparent that most efforts were directed toward developing more efficient, higher power output, lower cost devices and conversion systems by using the technology available at the time. Many concepts and ideas introduced during recent years follow in general past developments in applying contemporary technology and new materials. However, energy storage, low-use factor of solar irrigation systems and the high cost of such systems still need to be solved. The use of photovoltaic cells in an all electric system or in a hybrid system appears to be an almost ideal solar energy application for pumping irrigation water; if problems related to power conditioning can be eliminated, and if the cost of these systems can be decreased.
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Fig. 18. Schematicdiagram of Sandia Laboratoriesbuilt system.
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J.T. PYI"LINSKI REFERENCES
1. A. S. E. Ackermann, Z Roy. Soc. Arts, 538-565 (1915). 2. H. Heywood, Engineering, 176 (1953). 3. R. C. Jordan and W. E. Ibele, Proc. World Syrup. Appl. Solar Energy, Phoenix, Arizona (1955). 4. S. de Caux, The Cause of Motive Power, E. I. Norton, Frankfurt, Germany (1615). 5. C. Giintner, Scientific American Supplement, Vol. 61, pp. 25409-25412 (1906). 6. A. B. Mouchot, La Chaleur Solaire et les Applications lndustrieUes, Ed. Gauther-Villars,Paris, France (1869). 7. A. B. Mouchot, Comptes Rendus de l'Acad~mie des Sciences (Paris), France $1, 74 (1875). 8. A. B. Mouchot, Comptes Rendus de I'Acad~mie des Sciences (Paris), France 86, 132 (1878). 9. A. B. Mouchot, Comptes Rendus de l'Acad~mie des Sciences (Paris), France 87, 481 (1878). 10. A. Pifre, Le G~nie Civil 7, 797 (1878). 11. A. Pifre, Revue Scientific $, 15 (1883). 12. A. Pifre, Nature 26, 503-504 (1882). 13. S. P. Langley, The New Astronomy, pp. 91-116, Houghton, Mi~lin, New York (1896). 14. J. Ericsson, Nature 29, 217 (1884). 15. W. Adams, Scientific American 38-39, 376 (1878). 16. Editorial Article, Scientific American 53, 214 (1885). 17. C. F. Holder, Scientific American 84, 169 (1901). 18. H. R. Willsie, Engng News 61(19), 511 (1909). 19. G. Hally, Institution of Engineers and Shipbuilders in Scotland, Trans, Vol. 57, p. 347 (1913--14). 20. A. S. E. Ackermarm, The Society of Engineers, London. Trans. Vol. 103, p. 81 (1914). 21. Editorial Article, Engng News 66(12), 327 (1911). 22. A. D. Blake, Power 34, 506 (1911). 23. Editorial Article, Scientific American Supplement 76, 29 (1913). 24. Editorial Article, Scientific American 109, 334 (1913). 25. R. H. Goddard, Popular Science Monthly 115, 22-23, 157 (1929). 26. E. R. I-Iagemann,Solar Energy 6(1), 47 0962). 27. Preliminary Design Study for a 150 kW Solar-Powered Deep Well Irrigation Facility, Vol. I, Technical Proposal, November 1976, Honeywell, Energy Resources Center, Minneapolis,Minnesota. 28. F. Daniels, The Direct Use of Sun's Energy, p. 13, Bailantine Books, New York (1964). 29. C. G. Abbot, Smithsonian Miscellaneous Collections 98(5), 1 (1939). 30. C. G. Abbot, Ann. Rep. Smithsonian Inst. p. 99 (1943).
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