Water Hydro

[thirteen]

I will build a shed over the micro hydro system next year after it is in. I am wondering about iceing problems. Yes some will say common sense, but does anyone know of little problems that show up that can cause problems. The water will come under ground for 725 ft but I would hope that I would not have to heat the shed it's self. At times it does get 20 to 30 below for maybe a month at a time. It will be a high voltage system then 625 ft back to the battery transformers. Ice build up maybe the only major problem but with some of the small things there may be a hidden problem I would miss. Just asking.

[Warren]

Hello,

I have a micro hydro system that operates year around in the interior of British Columbia, elevation 3700 feet.  Winter temperatures can be lower than 20 below. Once there is an ice or snow cover over the creek the turbine operates without any trouble. The turbine is in a small unheated shed and I do have a build up of ice around the turbine from the spray but it has not caused any problem. The flow past the turbine is about 50 gallons per minute.

The only problem with ice is in the fall while the creek is still open and ice crystals develope in the flowing water. These crystals will attach to anything. I have a 4 inch diameter plastic pipe to the turbine and the ice crystals will block that opening at the intake. This only happens when we have cold clear nights in the fall and only lasts until the creek ices over.

I have a screen over the intake from the beginning of runoff in the spring until the leaves are off the trees in the fall. Then the screen is removed because of the ice crystals.

Warren

[Boss]

Do you have any pictures? These microhydro systems sound awesome.

[thirteen]

chance of things the same are odd. I am at 3750 ft elevation with about 38 ft of head. I will ne using 4 in pipe but the the creek gets to low in the summer so I will have to put in a solar system in for the 3 months of low water. The ice crystals, I never thought of the problems it could cause. Thanks for the info.  My property is in the lower part of Idaho's panhandle. near Grangeville, Idaho 83530. What kind of turbine do you have? Because of low head I may end up with a turgo but since it is not in yet that I will find out late next summer. I will be totally off grid for the nearest power is 4-5 miles away and I like it like that.

[miro]

There is an effect under cold conditions called frazzle ice. This is ice that is formed from super-cooled ice. By super-cooled, the freezing point depression is several tenths of a degree F.

But what happens is that the frazzle ice will form below the surface of the liquid water and may nucleate on a rough surface or where there is an small eddy. There have been documented cases where, in northern ALberta, boulders from a river bottom have become bouyant,  once the ice forms around them,  and have damaged turbines. ou can just imaging what happens when a big rock hits a big impeller.

In yur case teice might form inside the 4 in pipe and once the ice crystal nucleation stars, then it can grow rapidly and block the pipe.

So, what to do?

The key is to prevent the water from being super-cooled - virtually anything to help that should more or less fix the problem.

I think there were some profs at the Univ of Alberta that studied the frazzle ice problem and may have some papers on the subject.

[Warren]

Hello,

Here is a brief outline of our system: Total length of pipe 4400 feet, total head 160 feet, nozzel size 31/64 inch, turbine pitch diameter 3.69 inch.

I am using a stainless steel turgo turbine purchased from Hartvigsen-Hydro. The turbine is connected to a 2 horse power, 3-phase induction motor. The motor was rated at 575 volts, 1725 RPM. I am currently running the motor in a parallel star configuration and use three 9 micro farad capacitors to get the motor producing power.

When generating power the motor turns at 3080 RPM which is a bit higher than I wanted but at the time I could not get a larger turbine.

The 3-phase power is sent 200 feet to our house where it is reduced in a 3-phase transformer and rectified for our 12 volt system. Control is provided by two C 40 controllers in diversion mode. DC current at the rectifiers is about 50 amps at 14.1 volts.

The waterline is also used in the summer for irrigation so if you do any power calculations for this setup you will find I am not using the maximum power available. We just upgraded last year to this system. The previous system used a Delco alternator with a plastic turgo turbine and ran for ten years. It produced about 40 amps at 13.8 volts.

One thing I didn't mention is our intake is only about 8 to 10 inches below the creek surface in the winter. If you have a deeper intake depth you may not encounter the ice crystal problem or it may not be as severe.

I will try to get some pictures together,

Warren