why so complex??

[Ron Nieuwsma]

Hi, I'm new here.

I currently live on grid with a 4,000 watt peak diesel gen backup. The cut over is a simple switch that locks out grid power and switches to the Generator. It easily handles everything I have and to spare.

I am currently buying some property along a river that has no available grid power.

The river has great flow, a steady year round flow with only a 2 ft height flux from fullest to lowest.

So I started reading about microhydro power. Wow, seems so complex. Gives me a headache each time I try and wrap my noggin around it.

Okay I understand the head and flow. I believe I have an easy and ideal situation to put in a high head low flow. But if I had to I could go the other way too.

I read an article some years ago in Mother Earth News where a guy made his own hydro. It seemed to involve a good sized squirrel cage and a water heater.

Reading I seem to need so much more than this, tho the tech has progressed tremendously it seems. The turbine size is tiny to me.

Can someone dumb it down a bit for me - or point me to some dummy articles? Why can't it be as simple as my diesel? Okay, a few batteries inline to smooth it out or allow for when the frig kicks in, but it seems so much more complex than that. I realize the diesel has a governor that adjusts to load. But couldn't a few batteries work that out? I really do not understand. What makes it so much harder than diesel, esp if the water flow is kept constant?

Thanks for your patience and understanding - pls help,

Ron http://www.greenpowertalk.org/images/smilies/eek.gif

[Guy Dewdney]

with water, you cant regulate it quickly like an engine. That power has to go somewhere.

Most of the technology is similar to wind power, if you are off grid.

Hydro plant must charge batteries. Then the batteries will run an inverter, to give you leccy.

The charger must also have a way of getting rid of ALL of the excess power, all of the time - this is usually some form of 'dump load' - basically some heaters.

Imagine the time that the batteries are fully charged, and theres noone home - all that power has to be diverted to somewhere. Thats why you need full rated dump loads.

So - connect your turbine to a generator. Take the out of this to a battery charger / dump load controller. Take the battery output and stuff it onto an inverter, to give you clean good mains leccy.

You cant use the out of the generator directly (usually) as it varies up and down, giving you variable frequency / voltage which will muck up some appliances.

If you CAN make sure the water is constant, then you can do away with the batteries, and use the power from the genny directly, and use a 'diversion load controller' to regulate the power. This acts a bit like an electrical brake - so that when you are not using much power, the turbine is slowed by the 'brake'. When you turn on the toaster, the controller drops the 'brake' and allows full power to the toaster.

The disadvantage of this type is that you are limited to a max of whatever your turbine can make. Lets say thats 1kw. You cant run a toaster on 1kw. With the battery system, you can run the toaster, as it uses power stored up from 3am when everyone is asleep.

Does that help?

[Ron Nieuwsma]

Thanks Guy,

So right now a 3.5kw w/ 4kw peak & it does it all. My next place is going to be smaller not bigger. So my needs should be less. Since hydro is running all the time and I balance between peak and average it might be considerably less I think. ??

I am trying to *think* out loud as it were so you can see if I am on the right track.

I would like to minimize battery use if possible I think. Car batteries are readily available, but the real big deep cycle not. (I live in the Philippines right now.) Batteries also require maintenance and do not last so long in the hot humid tropics. (About half as long as they did when I lived in the US.)

My needs then would be a turbine and gen, with a voltage regulator of sorts next inline, then a water heater for dump and a set of batteries followed by an inverter and my regular breakers, power, and such. right?

By locating the batteries such closer to the generator I should be able to save on the cable costs since the longest run will then be 220 single phase ac. It should also reduce the electro-magnetic pollution to a safer distance from the dwelling. The total distance from the river to the cabin should be about 300 feet max, most up a steep grade.

Does this sound right? Am I missing anything?

What if I over-engineered the power and dumped most of it. Would that reduce the battery needs?

I have a lot of choices as far as stream draw and head/volume. Tho I have no spectacular drops I do have some 3-4 foot drops. Mostly it is just a nice steady downhill slant in the bottom of a gorge. The gorge is actually a bit wide and the hi-water marks do not approach the sides at all. The down side is there is no digging in dirt. It is pretty much all large boulders.

I want to do this as small an unintrusive as possible. Theft is a real problem here. Tho the location is very isolated teens sometimes come up river from the nearest village which is about 2 km's down stream. So, small and blending into the background as much as possible is ideal. And I am just powering a cabin of sorts. No heater (tropics), but a couple of fans, frig, computer, and lights - lastly a water pump with a large plenum / sand filter to clean it. Tho I hope to use the river to drive that too. The cabin will be in the woods and not very visible unless close up. There is currently a cabin on site that the owner is relocating to his new site. I planned on building in the same location.

I am just starting out on this project. So the more knowledge and ideas I can gather & incorporate in the planning stage the better off I'll be. For now the cabin will be a weekend retreat, but I hope to make it my permanent residence in a couple of years when my last child moves out and it is just my wife and I.

Is there anything happening in the industry which is worth waiting or planning for? What would be the simplest, least intrusive, and least maintenance of the types of turbines and generators? I really want to keep this in the KISS range as much as possible.

Thanks again Guy for the help. Anyone else want to comment?

Ron

[Guy Dewdney]

well, the simplest turbines are crossflows or kaplan/propeller.

To get these to work requires head - 3 - 4 feet isnt going to cut it. power = head x flow xgravity x efficiency (head in metres, flow in litres/sec, gravity = 9.81, and efficiency somthing like 0.6 to 0.8 in total)

Get some idea of your total power available. If the MINIMUM flow is enough to supply your total power requirements, then you dont need any batteries at all.

Theft - bolt it to a large boulder! then mash up the heads of the bolts / weld them / glue (epoxy) / security bolts / use allen bolts and hammer in a ball bearing etc etc. See if you can bury the cable at least (copper = nickable). Use waste pipe if you can for water (cheap / not worth anything). Maybe disguise leccy cable using old water hose?

[Ron Nieuwsma]

Okay I ran the load based on the manufacturers labels. Which in some cases seemed off.

For example my computers have variable input power supplies yet it only gives a single watt rating. Is that for 110 voltage or 220? I went with worse case in each.

My normal use should be less than 1kw. My high normal less than 3kw. My absolutely everything at the same time 5kw.

I looked a bit at systems, there really does not seem all that much diff in price breaks between 1kw and 3kw at the gen side. I do not know about controllers and everything else added in. But an extra $5-700, would be recooped fairly quickly I think. I had a harder time with the 5kw stuff. Seems less common and more expensive.

I think my next step will be to figure the total drop along my whole property river line and do the how long to fill a bucket test. Do you know a good source on a peep site? I was going to use gps, but it said that was too inaccurate. Takes me about 45 days to get delivery on what I order from the US, so it could still be awhile before I figure out the total drop unless I can find someone local with what I need. I know no-one in the survey business. Maybe I can use a tube level (basically a long aquarium tube with water in it. I have one about 30' long, maybe I can find one a bit longer.)

For security (esp vandals) I was thinking a small cement enclosure slightly up and into the gorge wall out of high water range. That might help with rust and corrosion too. (this being an island surrounded by salt water, rust and corrosion are real problems too.) Cover with rocks to taste and put a sturdy door and lock on it. Should blend in fairly well since its all big rocks there. Cover, bury, camouflage as best I can the pipes and cable conduit. A little strategic vine planting should help too. Since it is tropics that would quickly provide year round coverage too. The inlet and that pipe will be the hardest. Not sure how much noise it will make versus the natural river noise. Then make the tail race look like a feeder spring, which is common out here anyway.

Much of the teens out here are associated with bloods or crypts gangs so a little planning should help here too. Probably more mischief and tagging than anything, but I would hate to have a kid vandalize it and fry themselves.

More thinking out loud, but it all seems doable. Time to do the river study.

Ron

[Guy Dewdney]

I think you might need to do some basic electricity revision.

watts is power. Voltage is not relevant. A 100hp engine is a 100hp engine - it could be a 1 litre screaming motorcycle engine, or a 6 litre V8 running badly - they both make 100Hp.

Power (watts) = volts x amps. So your computer will take 500 watts, which is 2 amps at 250v or 4 amps at 120 volts (roughly).

Otherwise - I think you have got it.

The tube thing sounds feasible, albeit a little slow. You will need an assistant with a measuring stick. Good luck - its very tedious!

I dont know what a peep site is. Or what a 'blood or crypt gang' means!

Rust - I live in a coastal area - so I understand. Grease / paint / stainless steel or if not possible, see if you can use really old style nuts and bolts with really coarse threads. The best is an old british bolt called Whitworth - but I suspect you wont find that over there. UNC is probably close. Coarse threads will be easier to undo in years to come. Even dip bolts in hardc andle wax (doesnt wash off, slightly lubricates)

[Ron Nieuwsma]

Okay,

The peepsite is something I found mentioned on some howto hydro sites. Basically a level site with crosshairs; a handheld cheaper version of what the road survey crews use I think.

Okay now my next question. I have said my needs where 1kw/3kw/5kw dependent on how much of a possible load I wanted carried. That was based on the 220 voltage tags on my appliances. The 1kw mycrohydro units mentioned online: are they 1kw at 110volts or some other voltage rating. My needs are 1kw, 3, or 5 @ 220 volts. Which if I understand your last email would need to be doubled if the 1kw system sold as a mycrohrydro referred to 1kw at 110 volts. So that would put my needs at 2kw, 6, or 10 dependent on those ratings. Right?

Yeah the tube thing is a cheapy level, but it should be accurate and something I can do with easily and cheaply attainable supplies. I figure 3 people; 2 people - 1 on each end of the tube, the 3rd to use a tape measure to measure the distance and the 2 height levels of the tube and then record it. A little adding and subtracting should give total pipe distance and total drop.

I think possibly my friction will be higher than the runs I've seen pictured in the microhydro sites too. The sites show a fairly straight trench pipe. Since I am in a gorge, I have to follow the bends of the gorge and can't really trench much. The sides of the gorge go pretty steeply up about 75-100ft to the top in most places. This will add a number of bends to my pipeline increasing friction. I hope to do the survey this week, when I do I plan on videotaping it so I can show the bends to whomever I end up getting the generator from.

The bloods and the crypts are two internationally know gangs. They have their local versions or chapters in our area. They are known for violence, drugs, and vandalism. Ours actually seem less violent than most I read about; mostly spray painting, theft, and other vandalism.

Are there recommended suppliers for these things?

Thanks again Guy, you have really helped a lot!

Ron

[Guy Dewdney]

Okay,
Okay now my next question. I have said my needs where 1kw/3kw/5kw dependent on how much of a possible load I wanted carried. That was based on the 220 voltage tags on my appliances. The 1kw mycrohydro units mentioned online: are they 1kw at 110volts or some other voltage rating. My needs are 1kw, 3, or 5 @ 220 volts. Which if I understand your last email {you mean post...} would need to be doubled if the 1kw system sold as a mycrohrydro referred to 1kw at 110 volts. So that would put my needs at 2kw, 6, or 10 dependent on those ratings. Right?

Ron

wrong!


1kw is 1kw whether its 1 million volts or 2 volts.

This is a common misunderstanding - power = AMPS x VOLTS.

1kw = 9.1 amps x 110 volts
1kw = 4.2 amps x 240 volts

you would need a simple transformer - basically a big version of a 'wall wart' power supply, or a small version of what you see stuck op a electricity pylon / pole. This takes the volts and doubles it (or whatever you need to do) and halves (correspondingly) the AMPS or current.

Its a bit like water:-
you can have a high head, low flow (angel falls for example) or low head, high flow - think of a large weir. They both make the same power. The head, or height is the voltage, the amount of water per second is the current. Double the height = double the power. Double the water flow - double the power again.

[Ron Nieuwsma]

Okay, I completed the site survey.

The river is even more curvy than I thought, and the walls steep and rocky.

The first 350' the river only dropped slightly more than 21'

The next 385' the drop was a bit better; at close to 40'.

Both measurements are somewhat suspect. You were right about measuring with a tube being tedious. My helpers kept trying to doing running totals in their heads. I kept asking for each end to be measured for height each time, recording it in a notebook. But between the language barrier and their trying to be helpful I think I will order something to help and do it again.

Now the volume of flow was pretty awesome. Two big outcroppings of rocks forced the water to a narrow 2.5' gap at one point with a nice 9' drop. We stuck a paint bucket into it with a stopwatch timing. One half second later a very full bucket hard been wrenched out of hand and was a good ways down stream. It takes less than 1/2 a second to fill the bucket. The slowdown seems to be how fast you can stick the bucket in the path of water. The bucket only covers less than 1/2 the width of the fall. 10 gallons per second per half width. The river seems to be providing in excess of 20gallons per second or 1,200 gpm. Of course that is total stream.

Any ideas where to go next. I have been searching and reading, but I am still not sure what comes next. In my mind I thought I could order some kit and put it in, but not sure where to turn.

Thanks again, Ron

[Guy Dewdney]

Taking your figues as basically right you have 61 feet drop, with 1,200 gpm

The 'gross' energy of that is:-
75 litres / second (sorry - we moved into the 21st centuary in England...)
19M head
power = l/s x head x gravity x efficiency

so thats:-
75 x 19 x 9.81 (gravity) x 0.7 (a rough guess) = 9785 Watts or roughly 10kW


A not insignificant amount. So you can run 5kw worth of 'stuff' all the time, and only take half the (current) amount of water.

What are the regulations regarding taking the water - or is the stream 'dead' with no life in it? Taking that amount of water from a stream will seriosuly muck with the ecology.

Your next course of events should be based on:-
1) get permission to do this.....
2) decide on a method (batteries or not, dump loads, controllers etc)
3) buy it.
4) install it - its easier to bolt things down when they are there to check for clearance

One of the first things to look carefully at, which you can do whilst waiting for stuff to arrive, is build an intake system. In short - this is a dam, and a pipe with a 'trash rack' on it. look at self cleaning ones - they can be made at home - or bought.

lay the pipe. You need a 6" bore pipe. That aint going to be cheap, as it has to be able to withstand 2 bar of pressure, (28PSI) roughly - with a decent safety factor of ideally 5:1 - so it should be able to take 10 bar or 150 PSI to cover problems. You can get away with less than this.

Build a plinth for the turbine. Have some threaded bar sticking out of it to bolt stuff to.

Look at how to do the outlet of the turbine - this is CRITICAL - lots of the power is generated here. The outlet needs to be under water at all times, but with plenty of space for the water to go.


There ya go :-)