Page 278 - Handbook of Energy Engineering Calculations

Fitting new machinery to an existing site requires ingenuity. If enough of

the old powerhouse is left, the same setup for number and type of turbines
might be used. In other installations the power-house may be absent, badly
deteriorated, or totally unsuitable. Then river-flow studies should be made to
determine which of the new semistandard machines will best fit the

conditions.
Personnel costs are extremely important in small hydro projects. Probably
very few small hydro projects centered on redevelopment of old sites can
carry the burden of workers in constant attendance. Hence, personnel costs

should be given close attention.
Tube and bulb turbines, with horizontal or nearly horizontal shafts, are one
way to solve the problem of fitting turbines into a site without heavy
excavation or civil engineering works. Several standard and semistandard

models are available.
In low head work, the turbine is usually low-speed, far below the speed of
small generators. A speed-increasing gear box is therefore required. A simple
helical-gear unit is satisfactory for vertical-shaft and horizontal-shaft

turbines. Where a vertical turbine drives a horizontal generator, a right-angle
box makes the turn in the power flow.
Governing and control equipment is not a serious problem for small hydro
plants.

Related Calculations. Most small hydro projects are justified on the basis of

continuing inflation which will make the savings they produce more valuable
as time passes. Although this practice is questioned by some people, the
recent history of inflation seems to justify the approach.

As fossil-fuel prices increase, small hydro installations will become more
feasible. However, the considerations mentioned in this procedure should be
given full weight before proceeding with the final design of any plant. The
data in this procedure were drawn from an ASME meeting on the subject
with information from papers, panels, and discussion summarized by William

O’Keefe, senior editor, Power magazine, in an article in that publication.

ANALYSIS OF A LARGE-SCALE HYDROELECTRIC

ENERGY PLANT