Small Decentralized Hydropower Program National ... - Cd3wd.com

Para desarrollar oportunidades de manufactura
local, lo esencial es mantenerla simple, fuerte y de
costo efectivo. Hay algunas realidades aplicables a las
pequenas plantas hidroelectricas decentralizadas que
simplemente no se aplican a 10s sistemas mayores.
Los sistemas m&s pequenos normalmente
aprovecharan la corriente natural, es decir, que
utilizaran aguas cuyo costo para traer a la turbina
sera muy bajo. Para 10s fines de este analisis, con-
sideramos que el agua es gratuita.
En la mayora de 10s cases, sin la posibilidad de
crear reservorios, el sistema descartaria agua la
mayor parte de1 ano. El costo adicional de las tur-
binas de alta eficiencia, con 3 sin caractetisticas tales
coma contornos de flujo movible, simplemente no
resulta satisfactorio en la mayoria de 10s pequexios
sistemas decentralizados. En la ecuacidn donde la
Energia = Fhjo x Caida z @GGncia, la energia
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rerwnerada varfa directamente con el flujo y la caida
asi cone la eficiencia, de modo que se puede agregar
simplemente un poco m& de flujo o de caida para
resultar con la rnisma cantidad de energia con un
poco menos eficiencia. Un ingeniero interesado en
obtener la energia necesaria de una corriente sin
represa, no puede justificar un porcentaje, aun un
aumento de 10% en la eficiencia de la maquinaria
wando se desarta e! uso una corriente de agua. La
situation completamente opuesta ocurre cuando las
facilidades civik s incluyendo represas y compuertas
de control de desbordes son calculadas en funcion de1
agua usada por la turbina. Tambien hay otros puntos
importantes, entre ellos el case de que ya no
estatiamos hdiando con pequenas centrales
hidraulicas decentralizadas. Esta g-ran diferencia en
la filosofia de1 disefio posibilita la manufactura local
de equipos para pequeiias centrales hidroelectricas.
Sugiero que consideren comprar ciertas piezas para
la turbina-generador de manufactura local, de
grandes fabricantes de bombas de agua. Como un
simple ejemplo, si el flujo es de uno a tres pies
cubicos por Segundo, se podra utilizar toda la bomba
con exception de1 rotor. La base, e! eje, !os roda-
mientos, 10s sellos y toda la caja se podtin usar
directamente de 10s depositos. El impulsor debera ser
reemplazado por un rotor que podria ser disenado
For local manufacturing opportunities, we urge
you to keep it simple, sturdy and very cost-
effective. There are some truths applicable to
small oecentralized hydro that simply do no! app-
ly to larger systems. The smaller systems will
normally be run-of-stream, that is they will use
water that has had very little money expended in
bringing it to the turbine. For the purpose of
analysis, we assume the water is to be con-
sidered free.
In most cases, without “ponding” ability, the
system will discard water for a major part of the
year. The added cost of high-efficiency turbines,,
with or without features such as movable flow
contours, simply does not pay out on the majori-
ty of small decentralized systems. In the equa-
tion where Power = Flow x Head x Efficiency, -
11.8
the power recovered varies directly with
flow and head, as well as the efficiency, so that
we may simply add a little more flow or head to
give the same output power with a siightiy iower
efficiency. For the engineer interested in getting
the needed power from a stream without a dam,
a 5%, or even 10% increase in efficiency
cannot be justified when a stream of unused
water is being discarded. Quite the reverse would
be true if expensive civil facilities, including dam
and flood control gates, were costed against the
water used by the turbine. Several other things
would also be true, among them the fact that we
would probably not be dealing any longer with,
small decentralized hydro. This very large dif-
ference in resign philosophy makes possible the
local manufacture of small hydro equipment.
We would like to suggest that consideration be
given to the purchase of certain parts of your
locally-manufactured turbine-generator from a
large builder of water pumps. As a simple exam-
ple, with flows from one to 3 cubic feet per se-
cond, you could use the entire pump except the
runner. Base, shaft, bearings: seals and the en-
tire casing cou!d be used directly from “stock.”
The impeller would nave to be replaced with a
runner that could be designed locally or with the
aid of a consultant. There is a pump which I have
localmente, o con la ayuda de un consultante.Hay una converted several times to service as a hydro tur-
bomba que fue convertida varias veces para servir bine. For each cubic foot of flow, and with 8
coma una turbina hidroelectrica. Por cada pie cubic0 meters of head, the theoretical power is 2.2 kW.
de flujo, y con una cafda de 8 metros, la ener@a With a generator efficiency of about 90% and a
teorica es de 2.2 kW. Con una eficiencia de1 ?urbine efficiency apparently about 60%, we had
generador de aproximadamente 90%, y una efici(- ,verall efficiency near 55% and the unit produc-
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