Micro-hydro power generation

[RogerS]

I am very sceptical of this home generation.
300 watts wont cover your workshop lighting, let alone ANY mains powered machine.
Averaging output over 24 hours is not relevant. Try boiling a kettle with 300 watts, while watching the TV.
Then take into consideration how much you have spent on parts, even if you dont count a single hour of your time in making the damn thing.
THEN, calculate how much it costs to buy that much power from the grid.

Roof mounted solar systems on the other hand, do generate enough to be useful. Even if it is very expensive to install at least you can get some return on your outlay with the possibility of actually getting your money back, where this is all dead money.

Spot on, sb, and I foresee a lot of spreadsheet work to validate the project (if at all).

 

[Phil Pascoe]

:shock: :lol:

 

[RogerS]

This might be a good stating point perhaps because behind it the topology lends itself to making my very own reservoir

 

[MikeG.]

....... Even with small amounts you could heat water ......for example.......

This is the standard storage solution for small scale generation where there is no battery bank or grid storage/ buy back. The Hockerton Housing Project does this, for instance, with their wind turbine. They have massive hot water tanks, because they have a large turbine which often produces more than they need.

 

[Tris]

The Hockerton Housing Project does this, for instance, with their wind turbine. They have massive hot water tanks, because they have a large turbine which often produces more than they need.

This is exactly why we should look at hydrogen for fuelling cars, gas boilers etc. rather than batteries. Wind could power electrolysis.

Back to the original post though, does your land have enough fall to use an hydraulic ram pump to fill a higher reservoir?

 

[Dibs-h]

....... Even with small amounts you could heat water ......for example.......

For hot water I would have thought you'd be better off using thermal solar (evacuated tubes or flat panels if in a really sunny place).

 

[MikeG.]

....... Even with small amounts you could heat water ......for example.......

For hot water I would have thought you'd be better off using thermal solar (evacuated tubes or flat panels if in a really sunny place).

That's missing the point. This isn't about efficient heating of hot water, this is about efficient use of an electric supply, a supply which can generate significant amounts of power constantly but can't meet the normal peaks of household usage. To take advantage of this constant supply of low-grade power, you can either store it in a battery bank and then draw power from the bank for your needs, or you can store it as heat, and use the heat in the normal way (by showering, washing dishes etc). A battery bank is an expensive item taking a large space and requiring constant maintenance and monitoring, and it has a finite life. A hot water solution is cheaper, simpler, and lasts ad infintum.

 

[novocaine]

geo thermal and or a heat pump for water heating is the most efficient I believe, something I'd like to do but can't figure the cost.

whilst I agree somewhat with Bob that this is a bit pointless, that doesn't mean you can't do some front end investigation for the crack.
I'd suggest you build an impeller flow meter and drop it in the stream for a week or so and log the data, really you'd want a month now and month in summer so you can calculate an average flow for the year. from this you can work out how much energy you'd actually get.
a nice little build project with some electrics and programming chucked in for good measure.

I know of at least 4 companies who are looking at wind to hydrogen conversions (3 of which I've worked with over the last few years), it's a bit more involved than you would think but at this point in time is the only viable renewable energy storage method we have right now. Battery technology is simply not up to the task and heat storage is a pretty terrible way of doing it, Entropy is a puppy.
Chemical conversion is good but again, you get less than you put in, if your taking otherwise wasted energy (wind, water, tidal etc.) then go for it.

 

[RogerS]

...
Back to the original post though, does your land have enough fall to use an hydraulic ram pump to fill a higher reservoir?

Interesting. Never heard of one of those. But that got me thinking as we do have a large drop available and a natural 'valley' so rather than putting it at the top and nearer to the house, put it lower down. But then there's the cost factor of longer cable, labour etc. Lots to think about.

 

[Dibs-h]

That's missing the point. This isn't about efficient heating of hot water, this is about efficient use of an electric supply, a supply which can generate significant amounts of power constantly but can't meet the normal peaks of household usage. To take advantage of this constant supply of low-grade power, you can either store it in a battery bank and then draw power from the bank for your needs, or you can store it as heat, and use the heat in the normal way (by showering, washing dishes etc). A battery bank is an expensive item taking a large space and requiring constant maintenance and monitoring, and it has a finite life. A hot water solution is cheaper, simpler, and lasts ad infintum.

The leccy bit I understood and storing it in a battery bank - but questioned storing it as heat - given that PV isn't cheap as chips and there are better solutions (more efficient & probably more cost effective) if you are going to store it as heat.

Dibs

p.s. battery technology - there are some interesting LiOn (and other newer technologies) on the market that have a large capacity and don't take up oodles of room.

 

[RogerS]

..... A hot water solution is cheaper, simpler, and lasts ad infintum.

Now that is a cracking idea as I already have this doing nowt.



2500 litres

 

[MikeG.]

That's missing the point. This isn't about efficient heating of hot water, this is about efficient use of an electric supply, a supply which can generate significant amounts of power constantly but can't meet the normal peaks of household usage. To take advantage of this constant supply of low-grade power, you can either store it in a battery bank and then draw power from the bank for your needs, or you can store it as heat, and use the heat in the normal way (by showering, washing dishes etc). A battery bank is an expensive item taking a large space and requiring constant maintenance and monitoring, and it has a finite life. A hot water solution is cheaper, simpler, and lasts ad infintum.

The leccy bit I understood and storing storing it in a battery bank - but questioned storing it as heat - given that PV isn't cheap as chips and there are better solutions (more efficient & probably more cost effective) if you are going to store it as heat.

Dibs

p.s. battery technology - there are some interesting LiOn (and other newer technologies) on the market that have a large capacity and don't take up oodles of room.

I'm not following you Dibs. The question here is what to do with the output from a micro-hydro unit. Roger isn't looking at the best way of heating hot water, but at efficiently using a low grade electricity supply.

 

[Dibs-h]

I'm not following you Dibs. The question here is what to do with the output from a micro-hydro unit. Roger isn't looking at the best way of heating hot water, but at efficiently using a low grade electricity supply.

Mike - I think we are at cross purposes here (or thereabouts). My comment was solely in relation to TN saying you could heat water with a generated electricity supply - you can and but just in respect to heating water - probably not the most efficient way of doing it (by efficiency - I mean £/KWh or similar).

If someone wanted to - by all means.

Hopefully not clear as mud.

Dibs

 

[Halo Jones]

If you search for "Kris Harbour Natural Building" on YouTube he has a whole series on how he self built his own off-grid hydroelectric system.

 

[sunnybob]

Being not only a cheapskate, but an OLD cheapskate, I looked into this home windmill electric supply business over 40 years ago. I had to specifically order in the books at the local library because I was the only one who had heard of it.
I didnt have a stream to play with, so very carefully studied all the windmills, and oil barrels cut in half and re-welded offset, just about everything you could think of.
Again and again, I came back to it costing more to install and run than just pay the bill. IT AINT FREE. :roll: :roll:
I dont see any change since then, especially if you have to go to storage batteries and inverters and power control electronics, and the purchase 24 volt equipment to use it successfully

On the other side of this conversation, which has now split into power, and water, Then water heating through solar panels is so good that I cannot understand ANYBODY who has not installed them.
Admittedly, I get a lot more sun than most of you, but even on the darkest winter days, the water is still being heated, and even in the UK, you can turn your immersion heater off for 3 to 4 months of the year. Evacuated tubes are the modern standard, and they are extremely good.
Halo, that link was in the second or third reply on page 1. Within the first year had to rebuild the turbine, buy a new controller, modify the pipework, and all for a measly 1/3rd a of a Kw per hour. I've used almost an hours worth typing this reply :shock:

 

[Just4Fun]

The amount of water in Roger's video suggests plenty of flow, and then it's just a case of how far up the stream you can run a pipe to give you a good enough head.

OK, This might be a stupid question but why do you need to run a pipe upstream to get enough head? Does the presence of the pipe change the head at all? (If so, how much more head do you get by installing the pipe?) Or is the head already present on account of the water having that much fall even though it is not constrained within a pipe?

 

[Eric The Viking]

Nobody has mentioned the power wasted in energy conversion inefficiencies. It was a big reason why, years ago, I opted for solar water heating, rather than photovoltaic panels. We have aboutr 8m^2 and in the summer (when it's working), there's little need for any extra heat input (6-bed house). It's not complex either.

Assuming power losses aren't an issue, you might do any number of things to store your energy, for example, run a compressor and have a large air tank. A hot water system is very inefficient, because of the difficulty in insulating tank and pipework, whereas compressed air in a tank just sits there (pretty much), waiting to be used.

I like the idea of pumping to achieve a higher head/pressure of water in a storage reservoir, assuming you have a location for it.

Castle Drogo (Dartmoor) recently got their hydro system renovated and back on-line , albeit with modern generators (I think the Francis turbines are the originals):
https://www.bbc.co.uk/news/av/uk-englan ... stle-drogo
This has better detail:
http://www.lutyenstrust.org.uk/portfoli ... tallation/
Having been down the Teign gorge recently, I noticed the screen/filter at the top end of the system is mechanically cleaned automatically and regularly: the notes above indicate they had to improve the filtration to prevent fish and eels getting mashed up. The head isn't huge, probably only 50-100ft (it's hard to tell from the other bank).
See also:
https://finglewoods.org.uk/2016/12/19/water-power/
We used to walk along the top of the penstock pipe years ago. I think it's been covered up a bit since it was brought back into use.

 

[Phil Pascoe]

water heating through solar panels is so good that I cannot understand ANYBODY who has not installed them.

The last plumbing and heating guy I had do work for me told me not to bother with a commercial set up as the return was so poor because they've complicated the systems so much they are too expensive to install.

 

[sunnybob]

water heating through solar panels is so good that I cannot understand ANYBODY who has not installed them.

The last plumbing and heating guy I had do work for me told me not to bother with a commercial set up as the return was so poor because they've complicated the systems so much they are too expensive to install.

Phil, thats something that only you can discover, in exactly HOW theyve complicated stuff?

the best system now is a bank of 7ft long glass tubes with no water in them connected to a header tank that is the heat exchanger. Your mains water pressure forces water through the heat exchanger, and into a pressurised holding tank. Which feeds your hot taps. Just how complicated can that be? you need an expansion vessel and an over pressure release valve (both already in your heating boiler)and a holding tank, which you almost certainly already have unless youre on an instantaneous combi.

A couple years ago my brother who lives in London was approached by a solar heating salesman. My brothers house is a very small 2 bed terrace and the guy wanted over 5K to install the system. My brother thought about it for a couple days and then phoned to say he could not afford it. The salesman instantly knocked £1,000 off the price!
He didnt go ahead because now he felt he was being cheated. he should have done it.
Theres no down side to solar water heating. On this island alone there are something like a million properties, i have not yet seen one that does not have solar panels, they cant all be wrong :roll: 8)

 

[Eric The Viking]

There are two generic designs: drainback and fully pressurised.

The drainback has a reservoir tank, In the event of boiling temperatures in the panels (or freezing), the circulating fluid drains back and is stored until conditions change. That's what we have. It has one standard CH pump, a small controller and two thermocouples (a third for info only). That's one moving part, literally, and almost bombproof electronics (again, literally).

The more modern fully-pressurised ones use mostly glycol-based fluid. This apparently both improves the heat transfer and raises the boiling point and lowers the cooling point. They are complex and very environmentally unfriendly if they spring a leak. I agree with your installer, Phil.

My local installers in Bristol (who now do only PV), tell me they are used where "communal housing developments" (AKA 'blocks of flats') get brownie points according to the efficiency of their systems, not according to the reliability nor the capital cost.

It's greenwashing, and in part because the photovoltaic systems have made so much money for the industry. Our panel manufacturer went out of business some years back (the dodgy PV subsidies killed them), and I couldn't find suitable replacement panels, and, more to the point, the manufacturers of the few brands available here in the UK won't sell direct to the public nor allow self-install. So our 10+ year old panels have gone back into reworked housings.

We will be moving/downsizing in the next few years. When we start looking, anywhere with PV on the roof won't even get a visit. I feel very sorry for the owners, once the panels start to fail after 10-15 years, more so for those suckered into "roof leasing" schemes.

There are many good reasons why the systems in the tropics are mostly water heating...

E.

PS: in reply to Bob above, I agree it's conceptually very sensible, but you cannot run mains water through the panels. There has to be a primary system (through the panels), and a heat exchanger/tank. There are all sorts of reasons for this - limescale being but one. In fact the hot water tank wearing out (limescale) is one of the only replacements that should ever be necessary.