. The Helms Pumped Storage Plant near Fresno, CA helps to meet peak energy demand by pumping water at 25 °C from a lower to an upper reservoir during times of low electrical demand or high wind energy production, and releasing it for hydroelectric power generation during times of peak electrical demand. The vertical distance between the reservoir surfaces is 531 m. Reversible Francis pump/hydroturbine units – open continuous-flow systems – are used for both pumping and power generation. They move water uphill, like pumps, when supplied with an external power source. Then can also extract energy from water flowing downhill, like hydroturbines. Unlike the adiabatic steam turbines and compressors we have studied, these pump/hydroturbine units do not change the enthalpy of the water. Any frictional energy losses are rejected to the surroundings as heat. Kinetic energy changes in the water may be neglected.
Useful reading: Wikipedia articles on pumped storage hydropower, hydroelectricity, and Francis turbines.
a) When the Francis units are used as hydroturbines, each one accepts 84.95 m3/s of water and produces 404 MW. Find their efficiency: (desired output)/(required input) as hydroturbines. Hint: watch for the J to kJ conversion in the gz term, as you have done earlier for kinetic energy terms.
b) When the Francis units are used as pumps, their efficiency is 3 percentage points less than their efficiency as hydroturbines. Find the overall efficiency for pumped storage in this system – that is, the ratio of energy output to energy input per unit mass of water making a round trip from the lower to the upper reservoir and back.
. The Helms Pumped Storage Plant near Fresno, CA helps to meet peak energy demand by ...
A pumped-storage hydroelectric plant generates high value electricity during peak demand times, by allowing water (density 1,000 kg/m3) to run through a pipe from an elevated reservoir through a bank of turbines and then into a lower level reservoir. It then uses low-cost, off-peak electricity to pump the water back up into the upper reservoir The water surface in the very large upper reservoir (A) is 600 m above datum whilst that in the very large lower reservoir (B) is...
3- Assume a pumped hydro energy storage arrangement that pumps up water from a low- level water reservoir to a higher-level reservoir to store energy. The water then is running back from the top reservoir down to the low reservoir through the pipe by passing a turbine. Assume a reasonable case of your choice and calculate the efficiency of this arrangement for storing energy (i.e. the electrical energy delivered by the turbine divided by the electrical energy used by the...
Storage tank 18 m Pump Water is pumped from a lake to a storage tank 18 m above at a rate of 64 L/s while consuming 21.2 kW of electric power. Disregarding any frictional losses in the pipes and any changes in kinetic energy, determine (a) the overall efficiency of the pump-motor unit and (b) the pressure difference between the inlet and the exit of the pump. b) AP- a) 1 kPa
4. Water is pumped from a lake to a storage tank 20 m above at a rate of 90 Ls while consuming 25.4 kW of electric power. Disregarding any frictional losses in the pipes and any changes in kinetic energy, determine (a) the overall efficiency of the pump motor unit and (b) the pressure difference between the inlet and the exit of the pump. he 20m
An energy storage system uses the excess power available overnight to pump water 50 metersup a hillfrom alake and into a reservoir. During the day, when extra power is required, the water is then released through a turbine and generateselectricity1. In this system, as shown in the figure, a pump with an efficiency of 80% is used to transfer the water up the hill. a.How much energy is required to move the water up the hill [kJ/kg]?. b.How much power...
hydroelectric power plant problem provided in a standby plantr Tme enceCythe hyuidelectiic lali wiii The demand for electric power is usually much lighter 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 plant that will be used only a short time during peak periods. Utilities are also to purchase power produced during...
3-86 The 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 con- sumers 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 will ing to purchase power produced during the day from private parties at a high price. Suppose...
(b) The daily design load curve of a residential area is given in the table below. The hydropower facility providing the power has an effective head of 15 m and a plant efficiency of 0.85. What is the minimum daily flow (m3/s) that could meet the demand? What is the minimum required storage capacity (within-day storage) to meet the peak load? If the daily flowrate were 320m3/s, what would be the minimum required storage capacity? Would there be some water...
In the UK, the 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...
n = 32 Q1: 1.) Mention all types of energies and distinguish the macro-types of mechanical energy 2.) How is Bernoulli relation related to the main forms of mechanical energy 3.) Write Bernoulli equation in its three forms and name each components in the three forms 4.) Write the energy equation in its complete form. 5.) In the UK, the demand for electric power is usually much higher during the day than it is at night, and utility companies often...