Chapter 10 | 605also by contacting some condenser manufacturers. In a report,
describe the various types, the way they are designed, the lim-
itation on each type, and the selection criteria.
10–132 Steam boilers have long been used to provide
process heat as well as to generate power. Write an
essay on the history of steam boilers and the evolution of
modern supercritical steam power plants. What was the role
of the American Society of Mechanical Engineers in this
development?
10–133 The technology for power generation using geother-
mal energy is well established, and numerous geothermal
power plants throughout the world are currently generating
electricity economically. Binary geothermal plants utilize a
volatile secondary fluid such as isobutane, n-pentane, and
R-114 in a closed loop. Consider a binary geothermal plant
with R-114 as the working fluid that is flowing at a rate of 600
kg/s. The R-114 is vaporized in a boiler at 115°C by the geo-
thermal fluid that enters at 165°C, and is condensed at 30°C
outside the tubes by cooling water that enters the tubes at
18°C. Based on prior experience, the average heat flux based
on the outer surface of the tubes can be taken to be 4600
W/m^2. The enthalpy of vaporization of R-114 at 30°C is hfg
121.5 kJ/kg.
Specify (a) the length, diameter, and number of tubes and
their arrangement in the condenser to minimize overall vol-
ume of the condenser; (b) the mass flow rate of cooling
water; and (c) the flow rate of make-up water needed if a
cooling tower is used to reject the waste heat from the cool-
ing water. The liquid velocity is to remain under 6 m/s and
the length of the tubes is limited to 8 m.