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HYDRO-ELECTRIC INFORMATION |
HOW MUCH POWER CAN YOU GENERATE?
The
amount of power available depends on the dynamic head, the amount of
water flow and the efficiency of the turbine generator combination.
To get an idea about available power in watts, multiply the head in
feet, times flow in GPM, times 0.18 times turbine efficiency. Turbine
efficiency ranges from 25% to 50%, with higher efficiency at higher
heads. To get a rough idea, use 0.30 (representing 30%) as a
multiplier for efficiency. The Harris Pelton turbines are well suited
to higher head and lower flow situations. Flow is limited by nozzle
size (a maximum 1/2”). With the Harris, adjustment to variable flows
is as easy as switching a valve and dialing in the alternator.
Harris turbines are now available with permanent magnet (PM)
alternators. This option provides up to 50% efficiency. Higher flows
are accommodated by the ESD Turgo Turbines. They can have nozzles of
up to 1” diameter, and provide better efficiency at low heads. The
HI-Power Hydros are ideal for sites where water is available at
long distances from power needs. They generate 100+ volts AC that is
stepped down and rectified at the batteries. This allows the use of
relatively small wire for a distance of up to 10,000 feet. They can
also deliver up to 3600 watts where higher power is needed.
Pipelines
A
hydroelectric turbine operates from the pressure at the bottom end
of a pipeline. This pressure, usually measured in pounds per square
inch (PSI), is directly related to the head, or vertical distance
from where the water goes into the pipe at the top of the pipeline,
to the turbine located at the bottom of the pipeline. The pressure
at the lowest point of a pipeline is equal to 0.433 times the head,
(the vertical distance in feet). Pressure is important because it is
a determining factor in how much power is available and what type
of pipe is required. Polyethylene pipe can be used for pressures up
to 100 PSI, PVC pipe is available with pressure ratings from 160 to
350 PSI and steel pipe can withstand 1000 PSI or more. Check with
your local plumbing supplier for pipe ratings. Pipe diameter is very
important. All pipelines will cause the water flowing in them to lose
some energy to friction. The pipe must be large enough for the
maximum quantity of water it will carry. The pressure at the bottom
of a pipeline when water is not flowing is called static pressure.
When water is flowing through the outlet or nozzle of the
hydroelectric turbine, the pressure at the outlet is the dynamic
pressure or running head. If you install a gate valve on the
pipeline just above the turbine and a pressure gauge on a “T” fitting
just above the gate valve, you will read the static pressure on the
gauge when the valve is closed and the dynamic pressure when the
valve is opened. The maximum power that can be delivered by a
pipeline will occur when the dynamic pressure is approximately 2/3
of the static pressure. The actual flow rate of the water in a
hydroelectric system is determined by the diameter of the nozzle. We
will supply a turbine with the proper size nozzle for your site,
depending on the head, flow, length and diameter of the pipe. We
carry hydroelectric generators made by Energy Systems and Design,
HI-Power Hydroelectric, and Harris Hydroelectric. Use the
descriptions on our Hydro-Power Page to
help determine which turbine will work best for your site and power
requirements.
Let us help you design the system
If you
think you have a suitable site, contact us and we will help you
choose the best unit for your situation. Please provide us with the
following information about your site when calling:
1. Head –
The total vertical elevation from the place where the water enters
the pipe to the point where the turbine will be located.
2. Flow –
The number of gallons per minute that are available.
3.
Distance – The length of pipe that will be necessary to carry the
water from the pickup to the turbine. If the pipe is already
installed what is the type and diameter?
4.
Location – Distance from turbine to batteries.
Nozzle Selection
Power
output of a hydroelectric generator is determined by the pressure of
the water at the nozzle and the amount of water flowing out of the
nozzle. The larger the nozzle, the greater the flow will be. The
nozzle must also be sized small enough to keep your pipeline full
and keep the speed of the water in the pipe below five feet per
second. The nozzle selection chart on the next page shows water flow
through various size nozzles at given pressures. Use this chart to
determine what size nozzle and how many nozzles you need to
accommodate the flow of water you have and to deliver the amount of
power you need. A pressure gauge in the pipe feeding your turbine,
installed before the shutoff valve, can help you check proper
operation and diagnose problems. When the valve is shut off, the
gauge will read the static pressure in pounds per square inch PSI
(head in feet x .433). When the valve is turned on the gauge will
read a lower (dynamic) pressure.
The
difference between these two pressures represents your loss to
friction in the pipe. The greater the flow, the greater your loss
will be. (See pipe loss chart below for PVC pipe.)
Water Flow Information for Pumping and Hydroelectric Design
Flow Through Nozzles
The chart below shows flow through
various nozzles in GPM at a range of heads from 5 feet to 400 feet.
Use chart to choose what nozzle size to use and how many nozzles a
turbine must have to give the required flow to use all of the water
available in the system.
|
Head |
Nozzle
Diameter |
RPM for |
|
Feet |
PSI |
1/8” |
3/16” |
1/4” |
5/16” |
3/8” |
7/16” |
1/2” |
5/8” |
3/4” |
7/8” |
1.0” |
4”
Turbine |
|
5 |
2.2 |
- |
- |
- |
- |
6.18 |
8.4 |
11 |
17.1 |
24.7 |
33.6 |
43.9 |
460 |
|
10 |
4.3 |
- |
- |
3.88 |
6.05 |
8.75 |
11.6 |
15.6 |
24.2 |
35 |
47.6 |
62.1 |
650 |
|
15 |
6.5 |
- |
2.68 |
4.76 |
7.4 |
10.7 |
14.6 |
19 |
29.7 |
42.8 |
58.2 |
76 |
800 |
|
20 |
8.7 |
1.37 |
3.09 |
5.49 |
8.56 |
12.4 |
16.8 |
22 |
34.3 |
49.4 |
67.3 |
87.8 |
925 |
|
30 |
13 |
1.68 |
3.78 |
6.72 |
10.5 |
15.1 |
20.6 |
26.9 |
42 |
60.5 |
82.4 |
107 |
1140 |
|
40 |
17.3 |
1.94 |
4.37 |
7.76 |
12.1 |
17.5 |
23.8 |
31.1 |
48.5 |
69.9 |
95.1 |
124 |
1310 |
|
50 |
21.7 |
2.17 |
4.88 |
8.68 |
13.6 |
19.5 |
26.6 |
34.7 |
54.3 |
78.1 |
106 |
139 |
1470 |
|
60 |
26 |
2.38 |
5.35 |
9.51 |
14.8 |
21.4 |
29.1 |
38 |
59.4 |
85.6 |
117 |
152 |
1600 |
|
80 |
34.6 |
2.75 |
6.18 |
11 |
17.1 |
24.7 |
33.6 |
43.9 |
68.6 |
98.8 |
135 |
176 |
1850 |
|
100 |
43.3 |
3.07 |
6.91 |
12.3 |
19.2 |
27.6 |
36.6 |
49.1 |
76.7 |
111 |
150 |
196 |
2070 |
|
120 |
52 |
3.36 |
7.56 |
13.4 |
21 |
30.3 |
41.2 |
53.8 |
84.1 |
121 |
165 |
215 |
2270 |
|
150 |
65 |
3.76 |
8.95 |
15 |
23.5 |
33.8 |
46 |
60.1 |
93.9 |
135 |
184 |
241 |
2540 |
|
200 |
86.6 |
4.34 |
9.77 |
17.4 |
27.1 |
39.1 |
53.2 |
69.4 |
109 |
156 |
213 |
278 |
2930 |
|
250 |
108 |
4.86 |
10.9 |
19.9 |
30.3 |
43.6 |
59.4 |
77.6 |
121 |
175 |
238 |
311 |
3270 |
|
300 |
130 |
5.32 |
12 |
21.3 |
33.2 |
47.8 |
65.1 |
85.1 |
133 |
191 |
261 |
340 |
3590 |
|
400 |
173 |
6.14 |
13.8 |
24.5 |
38.3 |
55.2 |
75.2 |
98.2 |
154 |
221 |
301 |
393 |
4140 |
Pipe Loss Chart
Use the chart below to
determine what pipe size is required to efficiently allow necessary
flow for your power need. Once you know the required flow for your
system (gpm), find the head loss for various pipe sizes. Multiply
the head loss number by the length of the pipe divided by 100 and
you will get the loss of head for that pipe size. The actual head
minus the head loss will give you the effective head in the system.
|
Pipe Friction Loss Chart -
Head loss in feet per 100 feet of Schedule 40 PVC pipe |
|
|
Flow (GPM) |
|
1 |
2 |
3 |
4 |
5 |
7 |
10 |
15 |
20 |
25 |
30 |
40 |
50 |
60 |
70 |
80 |
100 |
150 |
200 |
250 |
300 |
400 |
500 |
|
PIPE DIAMETER (Inches) |
1/2 |
2.08 |
4.16 |
8.7 |
14.8 |
23.5 |
43 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
3/4 |
0.51 |
1.02 |
2.2 |
3.7 |
5.73 |
10.5 |
20.1 |
42.5 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
0.1 |
0.55 |
0.68 |
1.15 |
1.72 |
3.17 |
6.02 |
12.8 |
21.8 |
32.9 |
46.1 |
|
|
|
|
|
|
|
|
|
|
|
|
|
1-1/4 |
0.03 |
0.14 |
0.19 |
0.31 |
0.44 |
0.81 |
1.55 |
3.28 |
5.59 |
8.45 |
11.9 |
20.2 |
30.5 |
45.6 |
|
|
|
|
|
|
|
|
|
|
1-1/2 |
|
0.07 |
0.08 |
0.13 |
0.22 |
0.38 |
0.72 |
1.53 |
2.61 |
3.95 |
5.53 |
9.43 |
14.3 |
20 |
28.6 |
36.7 |
|
|
|
|
|
|
|
|
2 |
|
|
0.03 |
0.05 |
0.07 |
0.11 |
0.21 |
0.45 |
0.76 |
1.15 |
1.62 |
2.75 |
4.16 |
5.84 |
7.76 |
9.94 |
15.1 |
34.8 |
59.3 |
|
|
|
|
|
2-1/2 |
|
|
|
0.03 |
0.04 |
0.05 |
0.09 |
0.19 |
0.32 |
0.49 |
0.68 |
1.16 |
1.75 |
2.46 |
3.27 |
4.19 |
6.33 |
13.4 |
25.0 |
37.8 |
46.1 |
|
|
|
3 |
|
|
|
|
|
0.02 |
0.03 |
0.07 |
0.11 |
0.17 |
0.23 |
0.4 |
0.6 |
0.85 |
1.13 |
1.44 |
2.18 |
4.63 |
7.88 |
11.9 |
18.4 |
40.1 |
|
|
4 |
|
|
|
|
|
|
|
|
|
0.04 |
0.06 |
0.11 |
0.16 |
0.22 |
0.3 |
0.38 |
0.58 |
1.22 |
2.08 |
3.15 |
4.41 |
7.52 |
|
|
5 |
|
|
|
|
|
|
|
|
|
|
0.03 |
0.04 |
0.05 |
0.07 |
0.1 |
0.13 |
0.19 |
0.4 |
0.69 |
1.05 |
1.46 |
2.49 |
3.76 |
|
6 |
|
|
|
|
|
|
|
|
|
|
|
|
0.02 |
0.03 |
0.04 |
0.05 |
0.08 |
0.16 |
0.28 |
0.43 |
0.6 |
1.01 |
1.53 |
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