Question

You have been asked to evaluate the economic implications of various methods for cooling condenser effluents from a​ 200-MW steamelectric plant. There are two basic types of cooling​ towers: wet and dry.​ Furthermore, heat may be removed from condenser water by​ (1) forcing​(mechanically) air through the tower or​ (2) allowing heat transfer to occur by making use of natural draft.​ Consequently, there are four basic cooling tower designs that could be considered. Assuming that the cost of capital to the utility company is 12​% per​ year, your job is to recommend the best alternative​ (i.e., the least expensive during the service​ life). Further, assume that each alternative is capable of satisfactorily removing waste heat from the condensers of a​ 200-MW power plant. What noneconomic factors can you identify that might also play a role in the​ decision-making process?

Alternative Dry Tower Mech. Draft Wet Tower Wet Tower Dry Tower Mech. Draft Natural Draft Natural Draft Initial cost $4.7 million 20 200-hp I.D. fans 40 100-hp pumps $0.13 million 30 years $2.5 million $9.0 million $8.8 million Power for I.D. fans 40 200-hp I.D. fans 20 150-hp pumps $0.13 million None None Power for pumps Mechanical maintenance/year 20 150-hp pumps $0.12 million 40 100-hp pumps $0.09 million 30 years Service life 30 years 30 years Market value 0 100 hp 74.6 kW; cost of power to plant is 2.2 cents per kWh or kilowatt-hour; induced-draft fans and pumps operate around the clock for 365 days/year (continuously). Assume that electric motors for pumps and fans are 90% efficient.

Answer 1

wet Tocoee wet Tooes wet Pouoea wet Toues Toces mech doapt Natcoal daft mech d apt Nodenal Dapt 2.50 OL H 30 0rtial cost a.. 30 30 30 Lite Yeaers b. Service O. 09 o.13 O.12 O-13 cash operating expenses C. (o.09) (013) to.1 (o.13) d. rotal Exp per ahhum 8.33 g.33 8.33 8.33 Anuity Factor at 2/o e.. standaod Value) (a) .05642 30 Yeasis o.56482 1.08043 (le) O. 30020 Guilent nvest nent f. eufvalent ual Benef COst ( 1.ao043 O.43012 O 6422 1-I4642 highest Anual Deneftt taken Hence ANSwer