A number of attempts have been made by scientists to utilize solar energy f
or irrigation water pumping. It is mainly a problem of conversion of heat e
nergy available from the sun, to mechanical energy. Some ingenious methods
have been devised to utilize the available energy at low temperatures. This
paper reviews past efforts to develop solar thermal water pumping systems
which employ either conventional pumps or unconventional pumps, and emphasi
zes how the system modifications were made to suit different pumping condit
ions and requirements. (C) 1999 Elsevier Science Ltd. All rights reserved.