Dear Chris:
As penstock is of relative low diameter (4") and some long, at -20 �C must freeze if the water velocity is low and as you can see. I think that your isolation pipe idea is good. Our experience with low temperatures was with 36 kW, 48 m gross head MHP Plant "El Chenke", sited at Rio Cisnes Farm in chilean Patagonia, near Argentina border. The penstock is PVC 355 mm diameter, 285 m length, but buried 800 mm depth into the stony soil. Some days in winter temperature is as low as -17�C, the pipe never freeze, but forebay become completly freeze and flow of water stop, so the penstock must be drained and turbine shut down waiting for ambient temperature increase. Regards, Carlos E. Bonifetti Concepcion, Chile ----- Original Message ----- From: "Hoppy" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Tuesday, February 01, 2005 11:34 AM Subject: [microhydro] Freezing penstock > > > 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/
