Which micro hydro

[Drew Cutter]

I need some help figuring out what type of micro hydro system I need and
which mfg. to go with . Thanks. To be used for the house.

 

[SQLit]

I need some help figuring out what type of micro hydro system I need and
which mfg. to go with . Thanks. To be used for the house.

pretty hard to do with out specific information about the water source you
have.

cfm's or afm?
Head?
amount of power you want?

 

[Drew Cutter]

pretty hard to do with out specific information about the water source you
have.

cfm's or afm

What is cfm and afm ?

Head?
amount of power you want?

How do you figure out how much power ? The square footage of the house ?
What about selling the excess if it becomes possible ? I'm a total
newbie at this. Thanks.

 

[Steve Spence]

Do you have an existing electric bill? This will tell you your monthly
kWh usage. Most utilities will not buy back microhydro.

Steve Spence
Dir., Green Trust
http://www.green-trust.org

Contributing Editor
http://www.off-grid.net
http://www.rebelwolf.com/essn.html

 

[Drew Cutter]

I'm thinking of using micro hydro for a new built home , so i don't
have clue on the amount of kWh. What would be a good average for family
size home ? The property has a creek (looking to buy). Good amount of
rain fall in the fall and spring. 3 inches of rain a month , during the
fall and spring. From the map it looks like the source is a combination
of mountain and rainfall. The property is flat if this make a
difference. I don't have clue as which mfg. to go with once i have the
data to choose. reliability , repairs , etc . Thanks.

 

[Anthony Matonak]

I'm thinking of using micro hydro for a new built home , so i don't
have clue on the amount of kWh. What would be a good average for family
size home ? The property has a creek (looking to buy). Good amount of
rain fall in the fall and spring. 3 inches of rain a month , during the
fall and spring. From the map it looks like the source is a combination
of mountain and rainfall. The property is flat if this make a
difference. I don't have clue as which mfg. to go with once i have the
data to choose. reliability , repairs , etc . Thanks.

First, it might help if you read a little bit about how hydro works
and the various issues with it. This is one thing the internet is good
for as there are lots of websites with information.

Here are a couple.
http://www.homepower.com/education/comp_hydro.cfm
http://www.montanagreenpower.com/renewables/hydropower/hydropowerlinks.html

You will also find a web search engine helpful. Many people like this...
http://www.google.com/

What you need to know to start is a good estimate of how much power you
can expect from that creek. This is a combination of how far the water
falls and how much water there is. How far is called 'head' and how much
is measured by something like gallons per minute. The bigger these
numbers are, the more power you have available.

You also need to know if you are allowed to install a hydro generator.
Many locations have strange laws and regulations about what you can do
with water. If you are planning on selling the power back to a utility
then you need to find out from that utility if they allow it and their
requirements.

If you are going to build a new home then you should do your best to
make it as energy conserving as possible, especially if it's going to
be off-grid and you're going to generate all your own power. An average
American home uses about 24 kWh a day, 50 kWh a day if air-conditioning.
A good energy efficient household might use half to a third of that.
An extremely efficient home might only use a couple of kWh a day.

Only after you've found out if it's a good site for hydro and if it'll
even come close to providing what power you want, then you can find out
what particular technology you'll need. There are several types of
hydro generators and each works best with difference kinds of water
sources. Once you know what kind of hydro you need, then you can start
to research manufacturers.

If you do not feel comfortable learning this stuff yourself then it
shouldn't cost much to hire an expert to come out and survey the site
for hydro potential.

Anthony

 

[daestrom]

I'm thinking of using micro hydro for a new built home , so i don't
have clue on the amount of kWh. What would be a good average for family
size home ? The property has a creek (looking to buy). Good amount of
rain fall in the fall and spring. 3 inches of rain a month , during the
fall and spring. From the map it looks like the source is a combination of
mountain and rainfall. The property is flat if this make a difference. I
don't have clue as which mfg. to go with once i have the data to choose.
reliability , repairs , etc . Thanks.

As appealing as creating your own power with micro-hydro is, and as dull and
mundane as energy conservation sounds, when building a new house, extra
money spent on saving energy can be a much better investment.

The power available in any hydro system is the flow rate times the head. As
you say the property is 'flat', it doesn't sound like you have much
available head. With 'flat' land, building a dam to hold back the water and
raise the head (distance through which it falls) doesn't sound to good
either.

But here's some 'guesstimates'. If the 'creek' is 1 foot deep and 5 feet
wide, and flows along about 2 mph, then that would be about 5ft^2 x 2.9 ft/s
= 73.3 ft^3/s. That's a nice flow rate. Now, if you can divert 2/3 of that
through a micro turbine, this would give you about 48.9 ft^3/s. I don't
know exactly what you mean by 'flat', but let's assume you manage a small
dam and such to get about 3 ft of head for your micro-turbine.

So the amount of power is...

48.9ft^3/s * 62.2 lbm/ft^3 * 3 ft = 9123 ft-lbf / s One ft-lb/s is about
1.36 watts, so that's about 12.3 kW. If your turbine and generator are
about 81% efficient (90% each), then you get 7.4kW That would be a pretty
sweet set up.

But maybe your idea of 'flat' and 'creek' are different, so plug the numbers
in and see how it comes out. Could be better, could be worse. Then figure
out what you want to do. Keep in mind that permits for dams and things can
be difficult in different areas.

But a $2000 dollars in extra insulation and sealing on a new house can save
quite a bit of energy. Then you can just enjoy the natural beauty of the
'creek' without having to clear leaves and dead tree branches from the
turbine intake every spring and fall ;-) Any fish in it??

daestrom

 

[Drew Cutter]

The reason for building a dam is for when you are in dry season or low
water flow times ? If the source of the water is from the mountains and
the land isn't that far from mountains . Wouldn't the flow be ok most of
the time ?
In building a dam , couldn't just use very large boulder creating a
means of diverting the water , for a water fall ? How big of a dam would
you need to get adequate power ?

 

[Gìmmìe Bob]

Why would the head of water go down your pipe with a resistance at the end
when it can just follow the creek? One need a damn usually

An observation
Maybe flat doesn't mean horizontal. Creeks don't flow horizontal.

 

[Anthony Matonak]

The reason for building a dam is for when you are in dry season or low
water flow times ? If the source of the water is from the mountains and
the land isn't that far from mountains . Wouldn't the flow be ok most of
the time ?

Typically a dam is used to raise the water height. If you're creek
falls 3 feet over a long distance then putting in a dam at a low
point would give you that 3 foot fall right there. It's also helpful
if you want to raise the water height so it'll cover the intakes.

As a homeowner, it's unlikely you'll be able to have a dam big
enough for seasonable water storage. Every creek is different.
The only way to tell if your creek has good flow all the time
is to ask someone who knows or to watch it for a couple of years.

In building a dam , couldn't just use very large boulder creating a
means of diverting the water , for a water fall ? How big of a dam would
you need to get adequate power ?

Dam building is like building anything else, it's as simple or complex
as it needs to be. Can't building a house be as simple as nailing a
few boards together? Sure, but it wouldn't be a very good house and it
might fall down and kill you.

You might not need a dam at all. It depends on the property and how
that creek flows. No one could give you a sensible answer without
knowing that information.

Anthony

 

[SQLit]

What is cfm and afm ?

cubic feet per minute and acre feet per minute

 

[SQLit]

The reason for building a dam is for when you are in dry season or low
water flow times ? If the source of the water is from the mountains and
the land isn't that far from mountains . Wouldn't the flow be ok most of
the time ?
In building a dam , couldn't just use very large boulder creating a
means of diverting the water , for a water fall ? How big of a dam would
you need to get adequate power ?

You best check your local laws before you consider installing a dam. Where I
live the construction alone would be a direct path to court. Even a weir
will have the downstream neighbors would be drawing up law suits. Some
states like Colorado have sellable water rights. I looked at 200 acres on
the Colorado river once. Even though the river ran through the property by
law I was not able to use it. Could not even drill a well on the property.

You need to do some googling and reading. Your description of your property,
flat leads me to think your going to spend a lot more than you will get in
return.

Hydro no matter the size works on volume and head ( the amount of distance
the water drops ) Lots of head will make up for a small volume.

If your creek is not running 365 day a year you will probably be wasting
your time for unusable power. Unless of course you want a toy to play with.
Great idea,

 

[Drew Cutter]

What about the use of water wheels ? very efficient ? Does size matter ?

My understanding is that today turbine don't require a dam .

 

[daestrom]

The reason for building a dam is for when you are in dry season or low
water flow times ? If the source of the water is from the mountains and
the land isn't that far from mountains . Wouldn't the flow be ok most of
the time ?
In building a dam , couldn't just use very large boulder creating a means
of diverting the water , for a water fall ? How big of a dam would you
need to get adequate power ?

There are two different reasons for building a dam. One is to provide a
storage volume behind it to 'even out' the flow through the turbine between
wet and dry spells. The other reason is to improve the available head to
the turbine.

Boulder dam is an example of one that does both. Lake Mead forms a huge
storage area to even out the flow from season to season. And its tremendous
height adds to the energy available from each cubic foot of water that flows
through the turbines.

But on small rivers, such as those in upstate NY, we have several dams along
the length of the river. Each creates a 10 to 15 foot 'fall'. In spring,
excess flow is allowed to just overflow over the top of the dam as the river
valley is not deep and narrow enough to use as a reservoir (and the folks
living along the river would have to be displaced). In late summer, no
water overflows the top, and the turbine flow has to be reduced to keep the
level behind the dam from dropping so low that boats can't navigate up the
river. Such a setup is often called 'run-of-river' since whatever the river
flow is, is what you get for the hydro turbine.

As others have said, as a private land owner and a small creek, you're
probably not going to be able to build a very high dam. Blocking flow to
downstream to fill a reservoir would involve the water rights of others
downstream of you. And the liability of a dam bursting and sending a large
reservoir's amount of water downstream would require special
licensing/engineering.

This is why my sample uses just a small amount of head (3 feet). A *small*
dam that still allows 'run-of-river' type of flow would be a lot easier to
get approved in many areas. But, it reduces the amount of power you can
generate from a given flow.

daestrom

 

[daestrom]

There "incredibly smal head" mans at least 10 feet high.

For an 'overshot' wheel, yes. But an 'undershot' wheel can work with less
(as little as 3-5 feet).

Wheels are usually much less efficient than a proper turbine design. But
they do have a certain appeal.

daestrom

 

[Drew Cutter]

What do you think of the Fourney turbine / waterwheel combination ?

 

[Drew Cutter]

What do you think of the Fourneyron turbine / waterwheel combination ?

 

[George Ghio]

I need some help figuring out what type of micro hydro system I need and
which mfg. to go with . Thanks. To be used for the house.

This is how it is worked out. Put your numbers in and work it out. You
will either have enough energy in the water supply or not.

If the energy is not there better to find out before you spend up big.

Example

Site Specifications

Flow Rate = 10 Litres per second

Gross Head = 30 Metres

Allowable Head Loss = 5 %

Micro Hydro Efficiency = 60 %



So

Allowable head loss = 30 X.05

= 1.5 Metres

Net Head = Gross head minus Head losses

= 30 - 1.5

= 28.5

Power Out ofput of Micro Hydro Gen = Flow rate(L/s) X h (net headin
metres) X g(9.8M/s) XEfficiency of the Micro Hydre Gen.

10 X 28.5 X 9.8 X .06 = 1.68kW

Daily Energe Output = 1.68kW X 24 = 40.3 kWh