62232-mt----renewable Energy Resources

NR

Code No: 62232/MT

M.Tech. – II Semester Regular Examinations, September, 2008 RENEWABLE ENERGY RESOURCES (Power Engineering & Energy Systems) Time: 3hours

Max. Marks:60 Answer any FIVE questions All questions carry equal marks ---

1.a) b) c)

State the expression for hour angle and day length. Calculate the day length for Bombay on 1st December 1998. Calculate the angle made by beam radiation with the normal to a flat collector on December 01st at 9.00 A.M. solar time for a location at 280351 N. The collector is tilted at an angle of latitude plus 100, with the horizontal and is pointing due south.

2.a) b) c)

Explain the term power coefficient as applied to WECS. Explain the terms cut-in velocity and cut out velocity. Calculate the power developed in kW by a 6.0-meter diameter rotor operating in 32 km per hour wind at an altitude of 150 m and 250C temperature. The windmill efficiency including generator and transmission losses is 30%. Assume the density of air at that altitude and temperature as 1.13 kg/m3.

3.a)

Using Betz model, obtain expressions for torque, power and thrust coefficient of a wind machine. Discuss the factors involved in the selection of WEC systems for various applications.

b) 4.a) b) c)

What are the different types of generators used for wind energy extraction? What are the applications of control systems in the operation of wind turbines? What are the problems in maintaining a community biogas plant?

Contd…2

Code No: 62232/MT 5.a) b)

6.a) b)

7.a) b) 8)

::2::

Explain with simple sketches the continuous and batch type of bio gas plants with advantages of each one. Explain the effect of following parameters on the generation of biogas: i) pH value ii) Temperature iii) C/N ratio and iv) Loading Rate. Discuss the problems associated with the generation of power from ocean waves and describe with sketches the various methods of converting ocean wave energy into power. Calculate the theoretical maximum power output of a tidal electric power plant when the basin size is 5 km × 25 km and the tidal range is 1.5 meter. Estimate the energy content in a hot rock geothermal well. How is this connected to the useful working period of geothermal resource? What are the limitations in extraction of energy from the point of view of geothermal pollution? Explain in brief the following with neat sketches: a) Solar thermal applications b) Tidal power plants c) Operation of I.C engine with biogas d) Types of wind turbines and their applications. *****