Podcast
Questions and Answers
What are the three factors that determine the output from a wind energy converter?
What are the three factors that determine the output from a wind energy converter?
Why can't a wind turbine extract all of the wind's energy?
Why can't a wind turbine extract all of the wind's energy?
What is the maximum percentage of the available energy in wind that a 100% efficient aerogenerator can convert into mechanical energy?
What is the maximum percentage of the available energy in wind that a 100% efficient aerogenerator can convert into mechanical energy?
What is the typical percentage of the theoretical maximum that well-designed blades can extract?
What is the typical percentage of the theoretical maximum that well-designed blades can extract?
Signup and view all the answers
What is the formula for the kinetic energy of any particle?
What is the formula for the kinetic energy of any particle?
Signup and view all the answers
What is the formula for the amount of air passing in unit time, through an area A, with velocity V?
What is the formula for the amount of air passing in unit time, through an area A, with velocity V?
Signup and view all the answers
What is the formula for the mass m of air traversing the area A swept by the rotating blades of a wind mill type generator?
What is the formula for the mass m of air traversing the area A swept by the rotating blades of a wind mill type generator?
Signup and view all the answers
What is the principle behind the working of a wind mill?
What is the principle behind the working of a wind mill?
Signup and view all the answers
What is the primary function of plants in energy plantation?
What is the primary function of plants in energy plantation?
Signup and view all the answers
What is the minimum number of times more energy stored annually by natural photosynthesis process compared to the world's annual energy consumption?
What is the minimum number of times more energy stored annually by natural photosynthesis process compared to the world's annual energy consumption?
Signup and view all the answers
What is the primary purpose of energy farms?
What is the primary purpose of energy farms?
Signup and view all the answers
Which of the following is NOT a benefit of energy farms?
Which of the following is NOT a benefit of energy farms?
Signup and view all the answers
What is the percentage of total forest area in India?
What is the percentage of total forest area in India?
Signup and view all the answers
What is the primary goal of the program run by the Indian Institute of Science, Bangalore?
What is the primary goal of the program run by the Indian Institute of Science, Bangalore?
Signup and view all the answers
What is used to generate energy from various types of biomasses?
What is used to generate energy from various types of biomasses?
Signup and view all the answers
What is the capacity of projects taken up under DNES at various places in the country?
What is the capacity of projects taken up under DNES at various places in the country?
Signup and view all the answers
What is the main disadvantage of the upward machine?
What is the main disadvantage of the upward machine?
Signup and view all the answers
What is the advantage of the downward machine?
What is the advantage of the downward machine?
Signup and view all the answers
What is the effect of the tower on the blades in the downward machine?
What is the effect of the tower on the blades in the downward machine?
Signup and view all the answers
What type of wind-mill is mounted on a vertical shaft?
What type of wind-mill is mounted on a vertical shaft?
Signup and view all the answers
What is the shape of the rotors of Savonious wind turbines?
What is the shape of the rotors of Savonious wind turbines?
Signup and view all the answers
What is the disadvantage of the Savonious wind mill when the convex surface faces the wind?
What is the disadvantage of the Savonious wind mill when the convex surface faces the wind?
Signup and view all the answers
Why are Savonious wind mills not preferred for electric power generating purposes?
Why are Savonious wind mills not preferred for electric power generating purposes?
Signup and view all the answers
What is the advantage of providing 4-blades in a Savonious wind mill?
What is the advantage of providing 4-blades in a Savonious wind mill?
Signup and view all the answers
What is the primary advantage of the Darrieus wind-mill?
What is the primary advantage of the Darrieus wind-mill?
Signup and view all the answers
What is the range of capacity of Darrieus wind-mills?
What is the range of capacity of Darrieus wind-mills?
Signup and view all the answers
What is a disadvantage of the Darrieus wind-mill?
What is a disadvantage of the Darrieus wind-mill?
Signup and view all the answers
What is a characteristic of Darrieus wind-mill blades?
What is a characteristic of Darrieus wind-mill blades?
Signup and view all the answers
What is an advantage of wind energy?
What is an advantage of wind energy?
Signup and view all the answers
What is a problem that Darrieus wind-mills can experience?
What is a problem that Darrieus wind-mills can experience?
Signup and view all the answers
What is a benefit of wind energy?
What is a benefit of wind energy?
Signup and view all the answers
What is a characteristic of the Darrieus wind-mill?
What is a characteristic of the Darrieus wind-mill?
Signup and view all the answers
What is the primary function of acid formers in anaerobic digestion?
What is the primary function of acid formers in anaerobic digestion?
Signup and view all the answers
What is the optimal pH range for fermentation and biogas generation?
What is the optimal pH range for fermentation and biogas generation?
Signup and view all the answers
What is the effect of increasing temperature on anaerobic digestion?
What is the effect of increasing temperature on anaerobic digestion?
Signup and view all the answers
What type of bacteria are involved in methane formation?
What type of bacteria are involved in methane formation?
Signup and view all the answers
What is the equation that represents anaerobic digestion?
What is the equation that represents anaerobic digestion?
Signup and view all the answers
What is the temperature range for thermophilic bacteria?
What is the temperature range for thermophilic bacteria?
Signup and view all the answers
What is the purpose of heating digesters in cold climates?
What is the purpose of heating digesters in cold climates?
Signup and view all the answers
What is the equation that represents the anaerobic digestion of cellulose?
What is the equation that represents the anaerobic digestion of cellulose?
Signup and view all the answers
Study Notes
Factors Determining Wind Energy Converter Output
- Three factors determine the output from a wind energy converter: wind speeds, the cross-section of wind swept by the rotor, and the overall conversion efficiency of the rotor, transmission system, and generator or pump.
- No device can extract all of the wind's energy, as the wind would have to be brought to a halt, preventing the passage of more air through the rotor.
- The maximum possible energy conversion is around 60% of the available energy in wind, but well-designed blades can extract up to 70% of the theoretical maximum.
Power in the Wind
- The power in the wind can be computed by using the concept of kinetics.
- The wind mill works on the principle of converting kinetic energy of the wind to mechanical energy.
- The kinetic energy of any particle is equal to one half its mass times the square of its velocity (1/2 mV^2).
Up-ward and Down-ward Rotors
- The rotor can be classified as upward and downward machines.
- Upward machines have the rotor located in front of the tower, while downward machines have the rotor located behind the tower.
- Downward machines allow the use of free yaw-system and allow the blades to deflect away from the tower when loaded, but they suffer from wind-shadow-effect of the tower on the blades.
- Upward machines produce higher power, eliminate the effect of tower shadow on the blades, and result in lower noise, lower fatigue on the blades, and smoother power output.
Vertical Axis Wind-Mill
- In this system, the rotor is mounted on a vertical shaft.
- Two common configurations of vertical axis wind-mills are the Savonious wind mill and the Darrieus wind-mill.
- The Savonious wind mill has an S-type rotor, supported at top and bottom by two circular plates, with curved blades fixed on a central pipe.
- The Darrieus wind-mill has 2 or 3 thin curved aerofoil section, C-shaped blades, with both ends fixed to the vertical shaft.
- The advantages of the Darrieus wind-mill include the ability to mount the generator on the ground, no requirement for yaw mechanism, and high efficiency (35-40%).
Advantages and Disadvantages of Wind Energy
- Advantages of wind energy include:
- Pollution-free electrical energy generation
- Renewable and available free of cost
- Suitable for rural, offshore, and onshore areas
- Reliable and cost-effective for large capacity units
- No transportation required
- Disadvantages of wind energy include:
- Noise and lower power density compared to horizontal axis wind-mills
Energy Plantation
- Energy plantation is a means of extracting maximum solar energy by growing plants.
- Plants are grown especially for their fuel value and act as solar collectors.
- Energy farms are economical, free from pollution, and require no maintenance.
- They are the best alternatives for present fuel crisis and to replace fossil and nuclear energy sources.
Biogas Generation
- Biogas generation involves three phases: enzymatic hydrolysis, acid formation, and methane formation.
- The phases involve the conversion of cellulose biomass into simple compounds, acid formation, and methane formation by anaerobic bacteria.
- The anaerobic digestion process is represented by a general equation, and the digestion process is influenced by temperature, pH value, and other factors.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz covers the factors that determine the output from a wind energy converter, including wind speed, cross-section of wind swept by the rotor, and conversion efficiency.