PUHI — Just feet from the roadway, an irrigation ditch quietly and unobtrusively generated power.
Dr. Keiichiro Yamamoto from the Toyama National College of Technology in Japan was looking over his low-flow, 1 kilowatt hydroelectric generator at the ditch fronting the Kauai Community College gardens.
“We utilize the traditional principles of gravity, and couple it with the new technology in batteries to improve lives,” Yamamoto said.
Brian Yamamoto, an instructor at KCC, sponsored the Toyama professor, who took a year sabbatical to do his work on Kauai.
“He is the first international scholar we have had at Kauai Community College,” Brian said. “He’s already written a textbook and done the low-flow hydro research he set out to do when he got here.”
With less than a month before Dr. Keiichiro returns to Japan, Kyoko Ikeda, KCC’s international education coordinator, said there will be five professors from Japanese national colleges of maritime technology coming to visit the Puhi campus from Sept. 4 through 21.
“The professors are coming for a professional development program, and we are hopeful they will see the work done by Dr. Yamamoto and that will inspire them to spend time here,” Ikeda said. “Eventually, we want to send some of our American educators to Japan to teach and do research as well.”
Brian said Dr. Yamamoto comes from a region that is heavily involved in hydroelectric. He wanted to develop something that would help rice farmers, and began research on low-flow hydroelectric.
The irrigation ditch alongside the KCC campus road was sufficient to generate power, which in turn, powered equipment enabling Dr. Yamamoto to complete the infrastructure surrounding his 1 kilowatt power generation unit.
“We had a rate flow of about 10 gallons per second,” Dr. Yamamoto said. “That is enough to generate about 100 watts, enough power to charge one 12-volt, 100 amp-hour battery.”
Using that single battery, and coupled with a utility grade inverter, the battery produced enough power so Dr. Yamamoto could construct the surrounding infrastructure of a protective shed, catwalk and support bracing for the hydroelectric generation unit.
“Battery power, or Direct Current, is the universal language of power,” said Bob Conti of KCC, who worked with Dr. Yamamoto in teaching the principles of photovoltaic and sustainability.
“Twelve volt is 12 volt, no matter if you’re here on Kauai, or anywhere else in the world. Combined with a utility grade inverter, the battery provides usable power.”
Brian said with the exception of the utility grade inverter, and a small wind turbine, which helped the impeller create a vortex, everything was improvised.
“He didn’t want anything out of a kit box,” Brian said. “The vortex chamber is fashioned out of a portion of unused resin barrel and the impeller was carved out of a piece of hardwood. This is not a kit, but built as the research progressed.”
Dr. Yamamoto said the hydro unit is not used constantly, but only as needed or can be monitored.
“If it’s in use all the time and the water floods, the unit will be destroyed,” he said.
His catchment system, created out of plywood cut to fit the exit dimensions of the irrigation ditch, is suspended above the water by a block-and-tackle system when not in use, and dropped when power is needed.
This starts the flow of power which charges the battery, a 12-volt battery with half a charge needing about four hours to fully charge.
In the course of work that involved three different generation models, Dr. Yamamoto said there are improvements that must be made, including leaking water from the vortex chamber and trying to develop a unit which will work in even less water current.
As the days count down toward the end of Dr. Yamamoto’s sabbatical, his family left for Japan last week.
One of his son’s parting words to his father was — seek work!