PROBLEM SOLVING FOR WIND POWER AND MICRO-HYDRO POWER SYSTEM

 PROBLEM-SOLVING FOR WIND POWER AND MICRO-HYDRO POWER SYSTEM

A. 22.3 kW                       B. 25.96 kW                C. 29.67 kW                D. 33.38 kW


A.  1,077 W             B. 577W                   C. 415 W                     D. 215 W


Calculate the hydraulic power output of a 16-bladed windmill if the wind velocity is 4 m/s. System efficiency and rotor power coefficient are 80% and 0.3 respectively. The rotor diameter is 6 meters. Air density is 1.2 kg/m3.

A. 217 W              B. 723 W                     C. 317 W                     D.  327 W


What should be the starting torque of an 8-meter rotor diameter wind pumping system when its running torque is 950 Newton meters. 

A. 1,983 N-m                    B. 2983N-m                C. 3983 Nm                D. 1398 N-m


It is a structure that facilitates the entry of water into the conduit system.

 A. Weir                 B. Intake                     C. Headrace                D. None of the above

       Answer:  B


Conveys water from the intake to the forebay or surge tank.  

A. Headrace          B. Tailrace                   C. Penstock                 D. Weir

 Answer:  A

 

A hydraulic motor that converts the energy of water to mechanical energy.

  A. Generator        B. Turbine                   C. Dumper                  D. Engine

 Answer: B


     The volume of container used to measure:  50 liters

             Time to fill:  Trial 1 - 2 sec      Trial 6 - 2 sec

                                  Trial 2 - 2 sec      Trial 7 - 2.5 sec

                                  Trial 3 - 1.5 sec    Trial 8 - 2.5 sec

                                  Trial 4 - 1.5 sec    Trial 9 – 2 sec

                                  Trial 5 - 1.5 sec    Trial 10 – 2.5 sec

 

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%?  What is the power generated if the system efficiency is 70%?  

 A. 14.9 kW, 10.4 kW     B. 24.9  kW, 17.4 kW     C. 39 kW,  27.3 kW       D. 49 kW,34.3kW


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 kW                   B.  9 kW                     C.  13kW                              D. 16 kW

 

Structure built across the river which is used to divert the flow, and raise or maintain the water level.

 

 A. Headrace         B. Tailrace                   C. Forebay                  D. Weir

 Answer:  D

 

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

Answer:  B

 

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

Answer:  A

 

An electrical machine that converts mechanical energy to electrical energy

A. Engine              B. Generator               C. Hydropower                       D. None of the above

 Answer:  B

 

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?  The power coefficient is 0.4 and the system efficiency is 72%. Air density is 1.2 kg/m3.

 

A. 205 W              B. 155 W                     C. 105 W                     D.  75 W


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


Using the 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. 20.0 kW                       B. 30.0 kW                  C. 40.0 kW                  D. 50.0kW


The Betz coefficient is __.

 

A. 18/28                   B. 18/27                C. 16/28                 D.  16/27

Answer: D

 

 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

 Answer: B

 

If the wind velocity is doubled, the power will increase how many times?

A. 2 times                 B. 4 times              C. 6 times               D.  8 times

Answer: D

 

 

The ratio of the actual power converted by the rotor to that of the wind.

 

A. Power coefficient            B. Efficiency           C. Power output    D.  None of the above

Answer: A


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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