I just did a wee video about methods of estimating head and put it on Youtube. It’s a bit rough in places, but I hope it helps.
Shown in this video are the following methods:
Using a contour map (in this case an ordnance survey map taken on streetmap.co.uk)
Using Google Earth Pro to make a track with an elevation profile
Using a Johnson Sight Level that you can buy on eBay or wherever
Using a “clinometer” app on your phone
Using a pressure gauge on a pipe full of water
I did not mention that you can also use the clinometer to measure the angle of slope, and a long tape to measure distances, and thereby you can calculate the drop based on the triangle calculation for each step of the way. This can also work well if the device is calibrated. It also gives you an accurate pipe length.
An accurately calibrated aneroid altimeter can be a possible method on high head sites, but be wary of using GPS altimeters as they are not likely to be very accurate. Nor is Google Earth, to be honest. Each of these methods just gives you another rough indication which is why you should use several of them if possible and see if they agree at all with each other. There are more methods for sure including laser levels and tubes full of water but these are ones that I actually use.
In the end you just need this head measurement to satisfy yourself that your hydro site is going to delivery useful energy. As a ballpark figure, the output in Watts might be about 5 Watts for every metre of head and litre/second of flow. So if you have 100m head and 2 l/s flow then you can likely make 5 x 100 x 2 = 1000W or 1kW of power, which after 24 hours adds up to 24kWh units of electrical energy per day. More than an average home uses.
Mill sites are often ideal for the PowerSpout LH turbine. Here is a nice one in England installed recently. It’s a pity that the LH model is not available to buy at present due to a shortage of parts, but it will be back soon!
Mark: “[email protected]”, Livermore, Colorado 80536 is selling up a load of useful stuff from his place in Colorado. Please see his web pages
8T – 7 Starter Kits – One set of 3 fiberglass turbine blades for a 300W to 600W, 8′ diameter turbine. 24 + 3 Neodymium Rare Earth Magnets. One 10 Pound Roll of Magnet Wire. One Mercotac 230, 2 conductor, 250V, 30A electrical conducting rotating slip ring. Stub axle hub assembly. Retail $792, priced at $555 cash per kit.
12T – 7 Starter Kits – One set of 3 fiberglass turbine blades for a 2000W to 3000W, 12′ diameter turbine. 32 + 4 Neodymium Rare Earth Magnets. One 10 Pound Roll of Magnet Wire. One Mercotac 330, 3 conductor, 250V, 30A electrical conducting rotating slip ring. Stub axle hub assembly. Retail $1133, priced at $800 cash per kit.
80W off grid with 5m head.
Wins a prize for the most creative manifold.
380W off grid with 6m head. Note the heavy galvanised grating as turbine base.
660W off grid
1500W grid connected
This one is not so DIY, installed on a Pacific Island. 4 x PLT turbines running at 1750W each, flat out.
Some recent installations that I have helped with remotely. The owners of these turbines were kind enough to share these glimpses of the installation process, and of course they went ahead and tidied them up afterwards, but I rarely get the pictures of the final result.
Report KD 730 can be copied for free from my website: www.kdwindturbines.nl at the menu KD reports. The title of this report is: “Ideas about a 28-pole, 3-phase permanent magnet generator using the housing and winding of a 4-pole asynchronous motor frame size 80”. This generator is using 28 neodymium magnets size 40 * 7 * 3 mm and the magnet costs only about € 25. It is expected that this generator can be used with the original 230/400 V winding for 24 V battery charging if the winding is rectified in delta.
I have added figure 1 out of this report as an attachment and you can use this figure in a blog about this message.
ADDED 16th January:
Hereby I want to draw your attention to two KD-reports about rectification of an AC current.
Report KD 340 describes 1-phase, 3-phase and 2-phase rectification. Originally only star en delta rectification of a 3-phase current were described but recently I have added chapter 3.2.3 about rectification with three separate 1-phase bridge rectifiers. This way of rectification results in a somewhat higher voltage and power than star rectification but the rectifier losses are higher as the current always flows through six diodes.
Report KD 712 describes 5-phase and 9-phase rectification. Originally only 5-phase rectification was described but recently I have added chapter 6 in which rectification of a 9-phase winding is described. It appears that there are two ways to rectify a 9-phase winding and the way which is described in chapter 6.2 is favorable because this results in the highest power. The winding is split into three, 3-phase windings which are rectified separately. The three, 3-phase rectifiers are connected in series. The advantage of 9-phase rectification is that there is almost no fluctuation on the DC voltage and the DC current. This is of interest if the wind turbine is grid connected by a 3-phase inverter because it eliminates the need of using capacitors to flatten the fluctuations.
Several people have admired the finish on the turbine in my recent post about Ivan Juretic’s turbine, so I asked for details. Here is what he told me:
The blades and wooden parts of the tail are painted with a transparent polyurethane bi-component glossy varnish “Wood gloss” of Veneziani company.
I have been using this product for many years and I have a really great experience with it. It intensifies the beauty of wood and is extremely resistant to atmospheric agents over years, but is quite demanding for the application.
It is recommended to be applied in many coats, we’ve applied 10 times with brush, and in between coats the surface need to be over and over abrade with fine sanding paper.
All metal parts are galvanized and then yet protected with two layers of high quality coating based on modified epoxy “Hempel’s Selecta Metalni Efekt DTM”.
This paint is easy to aplicate with air spray, and the painted surface looks great with some twinkling sheen. We applied this paint also on the plywood part of th tail.
Some may say it’s all together too much, an exaggeration, but like what you said, and I believe, attention to the detail is always paying off.
In the attachment I’m sending to you Data sheets of both paints what we used and some additional pictures of the painting job!
In 2108 I reported a turbine build in Croatia by Ivan. It’s based on my ideas but Ivan added some engineering refinements. He just wrote to report that it is still going strong without problems.
That turbine works perfectly, for the third year in a row. And as I report to you in the mountains where it works there are really extreme conditions.
Cold, snow, ice, rain, hail, extreme turbulent wind, I don’t think it can get any worse.
But, no problems at all! It is just working.
After almost 20 months of constant operation we put it down this spring, because we just wanted to check everything and make regular maintenance.
There was little damage just on the blades leading edge, actually in the beginning I stick too short 3M protective tapes (just 30 cm) and now I repainted everything with 3 more layers of the amazing Veneziani Wood Gloss PU protective paint (use to be used for yachts) and sticked twice longer tapes.
Overall, the blades were in very very good shape, you can see it on the attached photo taken before I start reparation. The blades were made from larchwood.
The only other thing we had to change was the bronze bearing ring (blue in the drawing / bronze in the photo) on the bottom of the head because it was quite worn out. Now we’ve made it out of Teflon, and we’ll see how it behaves.
Also, the electrical system and control with your Tristar follower works really great, stable, reliable!
Again, thank you very much for all your help, and support for this amazing project.
I had a message today from a customer who has 3 turbines from 3 manufacturers. After a few years running he has this observation to make:
I have been very pleased with the PS and its nylon spoons which, even after almost 10 years at 70M head seem barely worn and I’m still on the original bearings. Both the Harris and Stream Engine needed a new runner and bearings.
Stream Engine turgo on left and Harris pelton on right. Note the holes in the Harris runner.
worn stream engine runner
Powerspout AC coupled to the off grid system with a Solis inverter.
Powerspout PLT turbine
corroded magnet rotor on the stream engine turbine