Renewable Energy Sources - Dec 2015
Mechanical Engineering (Semester 8)
TOTAL MARKS: 100
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks. 1 (a) What is the importance of 'Non-Conventional Energy Sources' in the context of Present Energy Scenario?(8 marks) 1 (b) Explain energy status of India & Maharashtra and role of NCES.(8 marks) 1 (c) Define the solar constant. What is its value?(4 marks) 2 (a) Define and explain the followings-
a) Latitude b) Hour angle c) Declination d) Day length(8 marks) 2 (b) Estimate the monthly average daily global radiation on a horizontal surface at Ratnagiri (16° 59' N, 72°5' E) during the month of March if the average sunshine hours per day is 9.5. Assume the values of a=0.31 and b=0.43.(7 marks) 2 (c) Find the days of the year on which the sun in directly overhead at 1200 h (LAT) at Pune (18°32'N).(5 marks) 3 (a) What is Betz coefficient? Show that the maximum power coefficient is 59% for a horizontal axis wind mill.(10 marks) 3 (b) The following data are given for family biogas digester suitable for the output of 10 cows: the retention time is 30 days, temperature 30°C, dry matter consumed per day is 2kg, and biogas yield is 0.24 m3 per kg. The efficiency of burner is 60% methane proportion is 0:8. Heat of combustion of methane is 28 MJ/m3. Calculate the volume of digester and the power available from the digester. Assume density of dry material in the fluid is 50 kg/m3.(10 marks) 4 (a) A tidal power plant of the simple single basin type has a basin area of 30×106 m2. The tide has a range of 12 m. The turbine however stops operating when the head on it fall below 3m. Calculate the energy generated in one filling (or emptying) process, in kWh if the turbine generator efficiency is 73%.(8 marks) 4 (b) Explain with neat sketches, how energy from Geothermal sources can be obtained in different ways.(5 marks) 4 (c) Propeller type wind turbine of 120m diameter is running with 40 rpm at a velocity of 15 m/s with maximum efficiency. The atmospheric pressure is 1.01325 bar and the temperature is 15°C Calculate:
i) The total power density in the wind stream
ii) The maximum obtainable power density
iii) The total power.(7 marks) 5 (a) Plot the variation of τf, τα and τ with the angle of incidence for the following cover system:
|Number of cover||= 3|
|Thickness of each cover||= 4mm|
|Refractive index of glass relative to air||= 1.52|
|Extinction coefficient of glass||= 15 m-1|
Write short notes on any four:
7 (a) Utilization of tidal energy.(5 marks) 7 (b) Site selection considerations for wind mill(5 marks) 7 (c) Fuel cells(5 marks) 7 (d) Micro-hydro power generation.(5 marks) 7 (e) Operational and environmental problem of geothermal energy.(5 marks)