by Francisco Gabriel Nuñez

Editor’s Note: Kiko, one of our current RE-Charge Pilipinas interns, is a mechanical engineering student at De La Salle University. He is doing applied research on solar-powered water pumps and wind turbines for potential application in communities. This is his first blog for ICSC.

Urban poor farmers still use pure muscle power – manually drawing water from open wells using buckets – to water their vegetables and herbs at the Yaokasin Techno Demo Farm at Brgy. 89, San Jose District, Tacloban City.

Muscle power has been replaced by the power of the sun this morning when we fitted a 500GPH 12V DC Bilge Pump powered by a 100W solar panel at the 1.5-hectare community garden.

“The solar pump reduces by an hour the usual two to three hours spent by farmers in watering the plants,” said agriculturist Reggie Ortega, manager of the community farm. “Speedy work means more productivity; it allows farmers to go home early to their families.”

I developed the solar-powered water pump prototype under the guidance of technical consultant Jelle Nijman. I was also assisted by Memar Lagmac, another RE-Charge Pilipinas intern from the Eastern Visayas State University.

The solar panels are directly connected to the DC pump, regulated by a tiny buck converter to ensure the voltage is at a stable 12V. Thus, the system rules out the typical solar-power setup of using batteries and a charge controller as this irrigation device is only needed when the sun shines bright and hot. There is no need for it in the evening, nor on heavily overcast and rainy days. The result is a simple, low cost irrigation system for the community farm.

With the depth of the open wells ranging only from 0.5 to 1 meter, a small DC pump that is capable of supplying a decent flow rate at a maximum height of 1.5m is all that is necessary for the job. This optimizes the system, avoiding over- or under-specification of the equipment for the particular work load. RE-Charge Pilipinas has also made efforts to make the solar-powered water pump a simple yet modular system so that the farmers themselves could easily improve or repair the panel stand and pump mountings.