Due to some firsthand experience in farming in India, I have a fair idea as to what are the needs of the Indian farmer. The GreenPeaceCompressorPump (GPCP) has been designed keeping all those needs and the specifications mentioned by the project specifically for farming in Bihar region.
The system requires a basic pumping device which is effective enough to pump water from a depth of 5m underground to irrigate 1 hectare of farm land. The GCPC’s principle is based on an engine that I designed a few years back. The details of the system and the engine can be read in the Design & Working Principle and the Description section. As you can see in the block diagrams, there is a reciprocating piston in a cylinder that uses just compressed air. It is attached to a source that provides compressed air at a constant pressure. The reciprocating piston then can translate its motion into a rotary to drive an external pump or itself act as a reciprocating pump to lift water using suction. The external pump could be any basic design rotary or even a radial piston pump used to lift water.