An electrical power plant has an overall efficiency of 15%. The plant is to deliver 150 MW of electrical power to a city, and its turbines use coal as fuel. The burning coal produces steam at 190°C, which drives the turbines. The steam is condensed into water at 25°C by passing through coils that are in contact with river water. (a) How many metric tons of coal does the plant consume each day (1 metric ton = 1 × 103 kg)? (b) What is the total cost of the fuel per year if the delivery price is $8 per metric ton? (c) If the river water is delivered at 20°C, at what minimum rate must it flow over the cooling coils so that its temperature doesn’t exceed 25°C? Note: The heat of combustion of coal is 7.8× 103 cal/g.
Trending nowThis is a popular solution!
Chapter 12 Solutions
EBK COLLEGE PHYSICS
- A coal power plant consumes 100,000 kg of coal per hour and produces 500 MW of power. If the heat of combustion of coal is 30 MJ/kg, what is the efficiency of the power plant?arrow_forwardShow that the coefficients of performance of refrigerators and heat pumps are related by COPref=COPhp1. Start with the definitions of the COP s and the conservation of energy relationship between Qh, QC, and W.arrow_forwardAn electrical power station uses 1.68 x 1014 J of heat input with an efficiency of 29.7%. (a) How much work is done? (b) How much waste heat is produced by the station? (c) What is the ratio of waste heat to work output? waste heat work outputarrow_forward
- When a certain type of coal is burned at a power plant, 22.6 ×106×106 joules per kilogram are released that is subsequently used to boil water and produce steam. The steam then does work on the turbine to produce electricity. If power is produced at a rate of 480 megawatts as 102000 kilograms of coal are burned per hour, what is the efficiency of the power plant?arrow_forwardA 2 ohm heater takes 5 amperes while submerged in 1400 grams of water contained in a vessel with a water equivalent to 100 grams. What is the efficiency of the system if the time required for the temperature to change by 80 degrees celsius is 3.1007 hours.arrow_forwardA heat engine has a solar collector receiving 600 Btu/h per square foot, inside which a transfer medium is heated to 800 R. The collected energy powers a heat engine that rejects heat at 100 F. If the heat engine should deliver 8500 Btu/h, what is the minimum size (area) of the solar collector?arrow_forward
- Consider a 24-kW hooded electric open burner in an area where the unit costs of electricity and natural gas are $0.10/kWh and $1.20/therm (1 therm = 105,500 kJ), respectively. The efficiency of open burners can be taken to be 73 percent for electric burners and 38 percent for gas burners. Determine the rate of energy consumption and the unit cost of utilized energy for both electric and gas burners.arrow_forwardAssume that the turbines at a coal-powered power plant were upgraded resulting in an improvement in efficiency of 3.14%. Assume that prior to the upgrade the power station had an efficiency of 38%, and that the heat transfer into the engine in one day is still the same at 2.63 x 1014 J. (a) How much more electrical power is produced due to the upgrade? 95581 v kW (b) How much less heat transfer occurs to the environment due to the upgrade? 800000000000c x Jarrow_forwardConsider two actual power plants operating with solar energy. Energy is supplied to one plant from a solar pond at 80°C and to the other from concentrating collectors that raise the water temperature to 600°C. Which of these power plants will have a higher efficiency? Explain.arrow_forward
- A heat engine does 9,200 J of work per cycle while absorbing 22.0 kcal of heat from a high-temperature reservoir. What is the efficiency of this engine? (1 kcal = 4186 J)arrow_forwardA woman expends 95 kJ of energy in walking a kilometer. The energy is supplied by the metabolic breakdown of food intake and has a 35 percent efficiency. If the woman drives a car over the same distance, how much energy is used if the car gets 8.8 km per liter of gasoline (approximately 20 mi/gal)? The density of gasoline is 0.71 g/mL, and its enthalpy of combustion is 49 kJ/g. Enter your answer in scientific notation. Compare the efficiencies of the two processes. kJ (driving)/ kJ (walking)arrow_forwardThe hot water from a geothermal source well steadily transfers 60 kW of heat to a working fluid that passes through a turbine. In units of Btu, how much energy is transferred to the working fluid during a 24-hour period?arrow_forward
- Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningGlencoe Physics: Principles and Problems, Student...PhysicsISBN:9780078807213Author:Paul W. ZitzewitzPublisher:Glencoe/McGraw-Hill
- College PhysicsPhysicsISBN:9781938168000Author:Paul Peter Urone, Roger HinrichsPublisher:OpenStax CollegePhysics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning