Concept explainers
Large wind turbines with a power capacity of 8 MW and blade span diameters of over 160 m are available for electric power generation. Consider a wind turbine with a blade span diameter of 100 m installed at a site subjected to steady winds at 8 m/s. Taking the overall efficiency of the wind turbine to be 32 percent and the air density to be 1.25 kg/m3, determine the electric power generated by this wind turbine. Also, assuming steady winds of 8 m/s during a 24-h period, determine the amount of electric energy and the revenue generated per day for a unit price of $0.09/kWh for electricity.
Want to see the full answer?
Check out a sample textbook solutionChapter 2 Solutions
THERMODYNAMICS (LL)-W/ACCESS >CUSTOM<
Additional Engineering Textbook Solutions
Fox and McDonald's Introduction to Fluid Mechanics
Heat and Mass Transfer: Fundamentals and Applications
DESIGN OF MACHINERY
Applied Fluid Mechanics (7th Edition)
Fundamentals of Aerodynamics
Thinking Like an Engineer: An Active Learning Approach (4th Edition)
- At a certain location, wind is blowing steadily at 10 m/s. Determine the mechanical energy of air per unit mass and the power generation potential of a wind turbine with 70-m-diameter blades at that location. Also determine the actual electric power generation assuming an overall efficiency of 30 percent. Take the air density to be 1.25 kg/m3.arrow_forwardA site is being considered for wind power generation. At this site, the wind blows steadily at 9 m/s for 2,579 hours per year. Assuming the wind velocity is negligible at other times for simplicity, determine the kWh/year that can be produced at the site for a turbine with a mechanical efficiency of 100% and an effective flow area of 5 m2. Use a value of 1.25 kg/m3 for the density of the air. Give your answer in killowatt-hours per year (kWh/year). Hint: I reccomend starting by finding the kinetic energy (kJ/kg) of the wind. Hint 2: Multiply the power generation (kW) by the number of hours of wind per year (h/year) to get kWh/year.arrow_forwardElectric power is to be generated by installing a hydraulic turbine–generator at a site 120 m below the free surface of a large water reservoir that can supply water at a rate of 1500 kg/s steadily. Determine the power generation potential.arrow_forward
- A 75-hp compressor in a facility that operates at full load for 2500 h a year is powered by an electric motor that has an efficiency of 93 percent. If the unit cost of electricity is $0.11/kWh, the annual electricity cost of this compressor is (a) $14,300 (b) $15,380 (c) $16,540 (d) $19,180 (e) $22,180arrow_forwardCan the combined turbine–generator efficiency be greater than either the turbine efficiency or the generator efficiency? Explain.arrow_forwardOne method of meeting the extra electric power demand at peak periods is to pump some water from a large body of water (such as a lake) to a reservoir at a higher elevation at times of low demand and to generate electricity at times of high demand by letting this water run down and rotate a turbine (i.e., convert the electric energy to potential energy and then back to electric energy). For an energy storage capacity of 5 × 106 kWh, determine the minimum amount of water that needs to be stored at an average elevation (relative to the ground level) of 75 m.arrow_forward
- Consider a river flowing toward a lake at an average velocity of 3 m/s at a rate of 570 m/s at a location 90 m above the lake surface. Determine the total mechanical energy of the river water per unit mass and the power generation potential of the entire river at that location. We take the density of water to bep=1000 kg/m3.arrow_forwardWater in the rural areas is often extracted from underground water source whose free surface is 65m below ground level. The water is to be raised 5 m above the ground by a pump. The diameter of the pipe is 10 cm at the inlet and 15 cm at the exit. Neglecting any heat interaction with the surroundings and frictional heating effects. What is the necessary power input to the pump in kW for a steady flow of water at the rate of 0.55 m3/s? Assume pump efficiency of 75%.arrow_forwardA water jet that leaves a nozzle at 50 m/s at a flow rate of 100 kg/s is to be used to generate power by striking the buckets located on the perimeter of a wheel. Determine the power generation potential of this water jet.arrow_forward
- Consider a river flowing toward a lake at an average velocity of 3 m/s at a rate of 500 m³/s at a location 90 m above the lake surface. Determine the total mechanical energy of the river water per unit mass and the power generation potential of the entire river at that location. Answer (0.887 kJ/kg, 443.7MW)arrow_forwardConsider a wind turbine with a blade span diameter of 142 m installed at a site subjected to steady winds at 7 m/s. By considering the efficiency of the wind-turbine and taking the overall efficiency of the wind turbine to be 54 percent and the air density to be 1.08 kg/m3, determine the electric power (kW) generated by this wind turbine to 1 decimal place.arrow_forwardThe demand for electric power is usually much higher during the day than it is at night, and utility companies often sell power at night at much lower prices to encourage consumers to use the available power generation capacity and to avoid building new expensive power plants that will be used only a short time during peak periods. Utilities are also willing to purchase power produced during the day from private parties at a high price. Suppose a utility company is selling electric power for $0.06/kWh at night and is willing to pay $0.13/kWh for power produced during the day. To take advantage of this opportunity, an entrepreneur is considering building a large reservoir 50 m above the lake level, pumping water from the lake to the reservoir at night using cheap power, and letting the water flow from the reservoir back to the lake during the day, producing power as the pump-motor operates as a turbine-generator during reverse flow. Preliminary analysis shows that a water flow rate of 2…arrow_forward
- Elements Of ElectromagneticsMechanical EngineeringISBN:9780190698614Author:Sadiku, Matthew N. O.Publisher:Oxford University PressMechanics of Materials (10th Edition)Mechanical EngineeringISBN:9780134319650Author:Russell C. HibbelerPublisher:PEARSONThermodynamics: An Engineering ApproachMechanical EngineeringISBN:9781259822674Author:Yunus A. Cengel Dr., Michael A. BolesPublisher:McGraw-Hill Education
- Control Systems EngineeringMechanical EngineeringISBN:9781118170519Author:Norman S. NisePublisher:WILEYMechanics of Materials (MindTap Course List)Mechanical EngineeringISBN:9781337093347Author:Barry J. Goodno, James M. GerePublisher:Cengage LearningEngineering Mechanics: StaticsMechanical EngineeringISBN:9781118807330Author:James L. Meriam, L. G. Kraige, J. N. BoltonPublisher:WILEY