WIND POWER AND MICRO-HYDRO POWER SYSTEM REVIEWER
Question 1: What is the power generated by a micro-hydropower plant with a gross head of 50 meters and a discharge of 20 gallons/second. Assume typical efficiency.
A) 22.26 kW
B) 25.96 kW
C) 29.67 kW
D) 33.38 kW
Question 2: What is the mechanical power output of a windpumping system with a rotor diameter of 8 meters. Average wind velocity is 3.5 m/s.?
A) 1,077 W
B) 577W
C) 415 W
D) 215 W
Question 3: Calculate the hydraulic power output of a 16-bladed windmill if the wind velocity is 4 m/s. System efficiency and rotor power coefficient is 80% and 0.3 respectively. Rotor diameter is 6 meters. Air density is 1.2 kg/m^3.
A) 217 W
B) 723 W
C) 317 W
D) 327 W
Question 4: What should be the starting torque of an 8-meter rotor diameter windpumping system when its running torque is 950 Newton-meters?
A) 1,983 N-m
B) 2,983N-m
C) 3,983 N-m
D) 1398 N-m
Question 5: It is a structure which facilitates the entry of water to the conduit system.
A) Weir
B) Intake
C) Headrace
D) NOTA
Explanation: An intake is a structure designed to facilitate the entry of water into a conduit system, such as a pipe or canal.
Question 6: Conveys water from the intake to the forebay or surgetank.
A) Headrace
B) Tailrace
C) Penstock
D) Weir
Question 7: A hydraulic motor that coverts the energy of water to mechanical energy.
A) Generator
B) Turbine
C) Dumper
D) Engine
Question 8: Using a bucket method, the following flow rate data were obtained from a waterfall with a gross head of 200 ft. The volume of container used to measure is 50 liters. The time to fill are: Trial 1 and 2 is 2 seconds, trial 3, 4 amd 5 is 1.5 seconds, trial 6 is 2 seconds, trial 7 and 8 is 2.5 seconds, trial 9 is 2 seconds and trial 10 is 2.5 seconds. What is the theoretical power that can be generated from the fall? What is the power generated by a micro-hydropower plant if the system efficiency is 70%?
A) 14.9 kW
B) 24.9 kW
C) 39 kW
D) 49 kW
Question 9: What is the power generated by a micro-hydropower plant in problem # 8 if the system efficiency is 70%?
A) 10.4 kW
B) 17.4 kW
C) 27.3 kW
D) 34.3kW
Question 10: A barangay official from a hinterland barangay of Agusan del Sur approached you to conduct a site assessment for a possible micro-hydro power system in their area. The power requirement of their barangay is 25 kW. During your assessment, the following data were obtained. The water source is a stream with a rocky bed and a width of 4 meters. The following depths from an X-section were measured 0.6 m, 1.0 m, 1.3 m, 1.2 m, and 0.75 m. Using a float method to obtain the stream velocity, for a distance of 50 meters the following times in 5 trials were recorded: 10 min, 9 min, 9 min, 11 min, 11 min. The gross head from the forebay site to the powerhouse site is 30 meters. From the data obtained, how many kilowatts of power is in excess? Assume a typical efficiency.
A) 6.22 kW
B) 9.22 kW
C) 13.22 kW
D) 16.22 kW
Question 11: Structure built across the river which is used to divert the flow, raise or maintain the water level.
A) Headrace
B) Tailrace
C) Forebay
D) Weir
Question 12: Structure designed to collect and flush sediments and other water-suspended materials to avoid entry to the penstock and eventually to the turbine.
A) Headrace
B) Settling Basin
C) Sludge Basin
D) Trash Rack
Question 13:Structure that facilitates the entry of water to the penstock. This serves as a temporary reservoir during the start of the operation.
A) Forebay
B) Tailrace
C) Headrace
D) Weir
Question 14:An electrical machine that converts mechanical energy to electrical energy
A) Engine
B) Generator
C) Hydropower
D) NOTA
Question 15:What is the actual power that can be generated from a 3.0 meter radius windpump if the average wind velocity of the place is 10 kph? Power coefficient is 0.4 and system efficiency is 72%. Air density is 1.2 kg/m^3.
A) 205 W
B) 155 W
C) 105 W
D) 75 W
Question 16:In a pumping system, what is the approximate energy requirement in kilowatt-hours if the daily water demand is 50 cubic meters and the pumping head is 20 meters.
A) 1.750 kWh
B) 2.725 kWh
C) 3.752 kWh
D) 4.527 kWh
Question 17:Using weir method in assessing the flow rate of a stream , the following data were obtained: Weir shape – triangular, depth of flow above the notch is 30 cm. What is the power potential of that water resource if there is an available drop of 60 meters?
A) 20.57 kW
B) 30.57 kW
C) 40.57 kW
D) 50.57 kW
Question 18:The Betz coefficient.
A) 18/28
B) 18/27
C) 16/28
D) 16/27
EXPLANATION:The maximal achievable efficiency of a wind turbine is found to be given by the Betz number B = 16/27.
Question 19:If you double the diameter of the rotor,the power will increase how many times?
A) 2 times
B) 4 times
C) 6 times
D) 8 times
Question 20:If the wind velocity is doubled , the power wil increase how many times?
A) 2 times
B) 4 times
C) 6 times
D) 8 times
Question 21:If the wind velocity is doubled , the power wil increase how many times?
A) Power Coefficient
B) Efficiency
C) Power Output
D) NOTA
Question 22:What is the tip-speed ratio of a 6-meter diameter rotor aerogenerator if the blade tip-speed is 30 m/s in a 4 m/s wind velocity?
A) 1.5
B) 7.5
C) 0.133
D) 5
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