Hydro Power

Hydro turbines can be seen as one of the most constant form of
energy production as the water that runs through it is constant
thus allowing a continuous form of production.

In order to see if hydro power is a viable option you need to be
able to measure the head and flow of your water source please see
below for instructions on how to do this:

MEASURING HEAD

Head is water pressure, created by the difference in elevation
between the intake of your pipeline and your water turbine. Head
can be measured as vertical distance (feet or meters) or as
pressure (pounds per square inch, newtons per square meter, etc.).
Regardless of the size of your stream, higher head will produce
greater pressure-and therefore higher output-at the turbine.

An altimeter can be useful in estimating head for preliminary
site evaluation, but should not be used for the final measurement.
It is quite common for low-cost barometric altimeters to reflect
errors of 150 feet (46 m) or more, even when calibrated. GPS
altimeters are often even less accurate. Topographic maps can also
be used to give you a very rough idea of the vertical drop along a
section of a stream's course. But only two methods of head
measurement are accurate enough for hydro system design-direct
height measurement and water pressure.

DIRECT HEIGHT MEASUREMENT

To measure head, you can use a laser level, a surveyor's
transit, a contractor's level on a tripod, or a sight level
("peashooter"). Direct measurement requires an assistant.

One method is to work downhill using a tall pole with graduated
measurements. A measuring tape affixed to a 20- foot (6 m) section
of PVC pipe works well. After each measurement, move the transit,
or person with the sight level, to where the pole was, and begin
again by moving the pole further downhill toward the generator
site. Keep each transit or sight level setup exactly level, and
make sure that the measuring pole is vertical. Take detailed notes
of each measurement and the height of the level. Then, add up the
series of measurements and subtract all of the level heights to
find total head.

WATER PRESSURE MEASUREMENT

If the distance is short enough, you can use one or more garden
hoses or lengths of flexible plastic tubing to measure head. This
method relies on the constant that each vertical foot of head
creates 0.433 psi of water pressure (10 vertical fee t creates 4.33
psi). By measuring the pressure at the bottom of the hose, you can
calculate the elevation change.

Run the hose (or tubing) from your proposed intake site to your
proposed turbine location. If you attach multiple hoses together,
make sure that each connection is tight and leak free. Attach an
accurate pressure gauge to the bottom end of the hose, and
completely fill the hose with water. Make sure that there are no
high spots in the hose that could trap air. You can flush water
through the hose before the gauge is connected to force out any air
bubbles.

If necessary, you can measure total head over longer distances
by moving the hose and taking multiple readings. Keep in mind,
however, that there is less than 1/2 psi difference for every
vertical foot. Except for very steep hillsides, even a 100-foot
hose may drop only a few vertical feet. The chance for error
significantly increases with a series of low-head readings. Use the
longest possible hose, along with a highly accurate pressure
gauge.

COMPUTING NET HEAD

By recording the measurements described in the previous
sections, you have determined gross head-the true vertical distance
from intake to turbine, and the resulting pressure at the bottom.
Net head, on the other hand, is the pressure at the bottom of your
pipeline when water is actually flowing to your turbine. This will
always be less than the gross head you measured, due to friction
losses within the pipeline. You will need to have water flow
figures (described in the following sections) to compute net head.
Longer pipelines, smaller diameters, and higher flows create
greater friction. A properly designed pipeline will yield a net
head of 85 to 90 percent of the gross head you measured.

Net head is a far more useful measurement than gross head and,
along with design flow, is used to determine hydro system
components and electrical output. Here are the basics of
determining pipe size and net head, but you should work with your
turbine supplier to finalize your pipeline specifications.

Head loss refers to the loss of water power due to friction
within the pipeline (also known as the penstock). Although a given
pipe diameter may be sufficient to carry all of the design flow,
the sides, joints, and bends of the pipe create drag as the water
passes by, slowing it down. The effect is the same as lowering the
head-less water pressure at the turbine. Head loss cannot be
measured unless the water is flowing. A pressure gauge at the
bottom of even the smallest pipe will read full psi when the water
is static in the pipe. But as the water flows, the friction within
the pipe reduces the velocity of the water coming out the bottom.
Greater water flows increase friction further.

Larger pipes create less friction, delivering more power to the
turbine. But larger pipelines are also more expensive, so there is
invariably a trade-off between head loss and system cost. Size your
pipe so that not more than 10 to 15 percent of the gross (total)
head is lost as pipeline friction. Higher losses may be acceptable
for high-head sites (100 feet plus), but pipeline friction losses
should be minimized for most low-head sites.

The length of your pipeline has a major influence on both the
cost and efficiency of your system. The measurement is easy .Simply
run a tape measure between your intake and turbine locations,
following the route you'll use you're your pipeline.

Remember that you want to run the pipeline up out of the creek
bed, when possible, to avoid damage during high water.