Pico-Hydro for Science: System 2.0 скачать в хорошем качестве

Pico-Hydro for Science: System 2.0

The video describes our new picohydropower system and the things we've learned. Since building and installing our first system about one year ago, we've learned a lot. The first generator was built according to the FiveGallonBucketGenerator design. It was soon joined by a second generator fed by the same penstock (pipe from the intake). In fall 2014, we began building two new generators to address some of the problems we encountered with the first. The initial plumbing was problematic. The intake kept clogging, as the pond filled with mud and gravel, so that the "up" time between maintenance was relatively short, less than two weeks. Even during "unclogged" operation, we were losing about half of the total 22 meters of head in the plumbing, with particularly large head losses in the nozzles and the abrupt reductions to those nozzles. (Note that the total head is shown incorrectly in the prior video). The electric side of the system had problems that we are still trying to solve. Our electronics are both noisy and sensitive to noise and putting two radiofrequency systems on one power supply led to interference, so we used the brute force solution and added a second generator. Some of the noise that yet persisted was eliminated by moving the grounding rods from both being next to the generators to each being adjacent to its respective enclosure housing the batteries and electronics. In addition to head losses in the plumbing, operating at low voltage (12 volts nominal) led to additional losses in efficiency in the transfer of power from the jets to the wire, so that total efficiency was less than 10%. Finally, there were problems with the homemade turbines. Although care was taken to ensure precise construction and placement of the turbine blades, the turbines were wobbly, so that even the best aiming of the jets could not produce optimal targeting of all turbine blades. (Also, the nozzle positions were glued into place and could therefore not be adjusted.) Finally, the second turbine was losing blades; many of the blades broke off, and we still don't know why: why that turbine and not the other? The video describes the new system, which employs some of the lessons we've learned, although we're still working on the electric side of the problem. Comparing the power output of the first- and second-generation systems is difficult because we don't yet have, for example, measurements of the flow rate through the nozzles. The new plumbing and turbines appeared to double the power output from each generator according to initial measurements (18 watts each vs. 9 watts previously), but we've turned that down a bit by reducing the flow through the nozzles. (The new nozzles have variable aperture sizes.) It appears that we could more than double the power output by using voltage converters to hold the alternator outputs at higher voltages, but we need that output voltage to be adjustable, because optimum operating voltage will vary with nozzle aperture. Appearing in the video are Jon Sanfilippo (MS student in Water Resources Engineering) and Stephen Lancaster (Assoc. Prof., College of Earth, Ocean, and Atmospheric Sciences), both of Oregon State University. Supporters of the Porter Creek Project include the Siuslaw National Forest, the National Science Foundation, and OSU's Institute for Water and Watersheds. In the Porter Creek Project, we are studying hydraulics and sediment transport in a gravel-bed stream in the Oregon Coast Range. Like any field study site, the location is off the grid. Some of the instrumentation can run just fine for a year or more on its own internal batteries, but radiofrequency electronics draw a relatively large amount of power. In particular, we have an antenna array for detecting the movement of gravel embedded with passive integrated transponder (PIT) tags. See the previous video for more information about the Porter Creek Project and the first-generation generators:    • Pico-Hydro for Science -- Updated and Edited   Disclaimer: Views and opinions expressed in the video do not represent an official position of the National Science Foundation.