Barn News

Black Swan Update – Hydro

This is a rare blog without pictures as there is literally nothing to show.  It’s almost like Claude Rains telling you to move along because there is nothing to see.  But it is not without exciting information (to me, at least).

The return of the hydro turbine core last week was a time of great celebration.  I am delighted that I decided to return that unit to the manufacturer for the replacement of the rotor bearings; I did not want to be learning-on-the-job by trying something I had not really done before – replacing the bearings on an expensive, high-stress high-precision delicately balanced machine.  I know that come a zombie apocalypse I will have to do it myself or find someone locally who can, so I purchase two extra pairs of the sealed bearings necessary for the task.  Given existing performance projections that gives me another 25-30 years of functionality to the unit.

Reassembling the turbine unit took almost no time, 10-15 minutes or so.  Reinstalling it into the system took about the same amount of time.  Tracking down the location of the breached water line from unrelated storm damage that had occurred since I dismantled the turbine took the longest.  A tree branch had fallen and cracked the penstock (the 2″ PVC pipe from the water capture to the turbine) disrupting the water flow to the turbine, and once the damage was found the repair took only a few minutes.  I keep a good inventory of repair parts on hand since my water line is above ground, snaking through the forest for almost 1200 feet.  I would love to have the water line buried but with our climate, topography and geology it would require digging a three-foot-deep trench a quarter mile in rocky sub-soil.  Until I inherit a new family tree with gobs of money I will make do with the status quo.

Once the system was all together and running I knew instantly that something was dramatically different.  For starters, the turbine unit was so quiet I turned it over just to make sure it was running!  For the previous nine years ever since the system was installed, when the turbine was operating under full load it produced a whine that was distracting for quite a long distance.  Since it was that way from Day One I had no idea it was not supposed to be so.  But now?  Eerily quiet, just barely audible even at the stillness of dusk.  Although I know what to listen for I still have to strain a bit from the front porch to hear it working.

A second observation was that the output of the unit had increased a fair bit.  I have not yet installed the new digital metering unit for that part of the system, but I can tell the difference in the integral monitor which is nothing more than a blinking light indicating the input current to the charge controller.  All I can say is that it was blinking about twice as fast as I had come to expect for that particular water flow.

I wrote back to the fellow who replaced the bearings with these observations, and asked him if he noticed anything during his work (he succeeded the previous owner of the company since I purchased my unit a decade ago).  He confirmed that he noticed one of the bearings was not seated properly  and he took special care in aligning everything correctly.   It appears that the misalignment caused both a whine in the turbine in operation and also some substantial drag on the turbine rotor shaft.  Hence the “new” turbine is both quieter and more efficient in operation.

Who knows?  Maybe the properly aligned bearings will last 20 years instead of 8-10.

Needless to say I am thrilled with this outcome, and await the developments in the solar panel controller malfunction situation.