I'm very new to this list but, from my experience moving water through 4 inch or even 3 inch should not freeze at that temperature. I have 1200 feet of 4 and 3 inch pvc on top of our very rocky ground and it has not frozen (we have about the same head per foot of pipe). From my experience, unless there is some mitigating factor water won't freeze in pipe as small as 11/2 inch. (my experience is that water in smaller pipe starts turning 'slushy' at about 5 F).
While we do not have as much cold weather as you, sometimes it gets that cold here for sustained periods. And over 20 some years about everything that can, has happened to our water pipe. Here are a few things that happen to mine which will cause it to freeze. 1. water flow blocked at top. (I have to force myself to a schedule of checking the intake for debris. 2.air vacuum somewhere in pipe slowing down flow (this is my guess as to the cause -need to install airvents - a problem I had two weeks ago when it got real cold was the air vents froze closed -fortunately I noticed a decrease in water flow and went up and checked before their was a real problem). 3. Water blocked at bottom. (we use the water for our house and we 'squeeze' it (drop the pipe diameter to an inch) below the house to give us water pressure. and this small pipe can freeze when the temp drops real low stopping the water flow up the pipe and causing it to freeze. Leigh Hauter The Plains, Virginia At 9:34 AM -0500 2/1/05, Hoppy wrote: >Dear Group, > >Has anyone had experience running micro hydro systems in freezing >(-20C) conditions? > >I have a 4 inch (100mm) penstock pipe that froze solid. It's 440 >feet long but only 30 feet head. Because of the rocky landscape, I >was unable to bury about 200 feet of it. > >The local "experts" consensus was that the flowing water would not >freeze in the pipe - but of course it did. It's possible that the >intake somehow got partially blocked and I can see how this reduced >flow could layer ice and eventually block the pipe. > >However, assuming the water flow is full and continuous, would the >pipe always freeze? > >Can anyone suggest some solutions? Wrap the pipe in insulation? > >How large a penstock diameter would you need so that the flowing >water wouldn't freeze? > >Any help would be much appreciated. > >Many thanks, > >Chris Hopkins, >Quebec, Canada > > >[Non-text portions of this message have been removed] > > > > > > > >Does your company feature in the microhydro business directory at >http://microhydropower.net/directory ? If not, please register free >of charge and be exposed to the microhydro community world wide! > >NOTE: The advertisements in this email are added by Yahoogroups who >provides us with free email group services. The microhydro-group >does not endorse products or support the advertisements in any way. > >More information on micro hydropower at http://microhydropower.net > >To unsubscribe: send empty message to [EMAIL PROTECTED] >Yahoo! Groups Links > > > > ------------------------ Yahoo! Groups Sponsor --------------------~--> In low income neighborhoods, 84% do not own computers. At Network for Good, help bridge the Digital Divide! http://us.click.yahoo.com/EA3HyD/3MnJAA/79vVAA/FGYolB/TM --------------------------------------------------------------------~-> Does your company feature in the microhydro business directory at http://microhydropower.net/directory ? If not, please register free of charge and be exposed to the microhydro community world wide! NOTE: The advertisements in this email are added by Yahoogroups who provides us with free email group services. The microhydro-group does not endorse products or support the advertisements in any way. More information on micro hydropower at http://microhydropower.net To unsubscribe: send empty message to [EMAIL PROTECTED] Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/microhydro/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
