.

The lower the heat consumption of an engine per indicated horse power,
the higher its economy and the less the number of heat units must be
imparted to the steam generated. This in turn leads to the lowering of
the amount of fuel that must be burned per indicated horse power.

With the saving in fuel by the reduction of heat consumption of an
engine indicated, it remains to be shown the effect of the use of
superheated steam on such heat consumption. As already explained, the
use of superheated steam reduces condensation not only in the mains but
especially in the steam cylinder, leaving a greater quantity of steam
available to do the work. Furthermore, a portion of the saturated steam
introduced into a cylinder will condense during adiabatic expansion,
this condensation increasing as expansion progresses. Since superheated
steam cannot condense until it becomes saturated, not only is initial
condensation prevented by its use but also such condensation as would
occur during expansion. When superheated sufficiently, steam delivered
by the exhaust will still be dry. In the avoidance of such condensation,
there is a direct saving in the heat consumption of an engine, the heat
given up being utilized in the developing of power and not in changing
the condition of the working fluid. That is, while the number of heat
units lost in overcoming condensation effects would be the same in
either case, when saturated steam is condensed the water of condensation
has no power to do work while the superheated steam, even after it has
lost a like number of heat units, still has the power of expansion. The
saving through the use of superheated steam in the heat consumption of
an engine decreases demands on the boiler and hence the fuel consumption
per unit of power.

Superheated Steam for Steam Turbines--Experience in using superheated
steam in connection with steam turbines has shown that it leads to
economy and that it undoubtedly pays to use superheated steam in place
of saturated steam. This is so well established that it is standard
practice to use superheated steam in connection with steam turbines.
Aside from the economy secured through using superheated steam, there is
an important advantage arising through the fact that it materially
reduces the erosion of the turbine blades by the action of water that
would be carried by saturated steam. In using saturated steam in a steam
turbine or piston engine, the work done on expandi