In areas with abundant sunshine during the growing season, as well as accessible groundwater, this low-cost solar water pump could be a great alternative to diesel pumps for irrigating fields and enabling more predictable yields for small farmers.
The Sunflower pump, from Futurepump, uses a solar collector and a steam boiler to drive a water pump capable of a potential daily output of over 10,000 liters from a well with a 10 meter water depth, and is simple to use and easy to maintain.
"The solar collector concentrates sunlight onto the water-filled boiler, producing steam which is piped to the engine. A cam attached to the flywheel shaft opens an inlet valve. Steam enters the cylinder and the pressure pushes the diaphragm piston forward activating the water pump and rotating the flywheel. The inlet valve closes, the exhaust valve opens and as the pressure drops and the flywheel inertia pushes the piston to the top of the cylinder and the cycle repeats." - Sunflower
According to the company's website, the Sunflower, which costs about $400 to purchase, could be appropriate for certain sites, including those with clear skies and sunshine during the growing season, a shallow water table (the deeper the water table, the slower the pumping rate), a lined well or borehole, and a quick well recharge rate.
The pump isn't portable, so the risk of theft is minimal, and owners of the Sunflower could expect a recoup the cost in as little as a year (when compared to operating a petrol-based pump). The device is built around the principles of appropriate technology, and while it does need regular maintenance, it is a relatively simple design which can be easily serviced with low-cost parts.
"Designed with durability and maintenance in mind, it has no electronics, and is about as complex as a bicycle." - Sunflower