1. Windmill Evolution
1.1. We first decided on a vertical windmill, but then it wouldn't spin after it was done, so we turned it horizontal and now it works
1.2. Horizontal: how do we attach the blade on top of the stalk without the stalk falling?
1.2.1. Create a stable base for it. (Triangles are the most sturdy structure!) We used lots of thin pieces of wood for support, and even added weights to ensure the windmill wouldn't topple over
1.3. Vertical: if the stalk also has to move along with the blade, does that mean there's more mass and harder to spin?
1.3.1. We chose this one and built it vertically, but we have now encountered the problem of 'ITS NOT WORKING.' We found out it worked best at a slanted angle..... so we would need to make another base to address this issue
1.3.1.1. We further decided that our windmill simply wasn't functioning well, and we abolished the design.
2. Stability
2.1. We thought that the one wood stick by itself would be too flimsy, so we added three more and glued them together to increase the mass it could hold
2.2. We added a really thick base so the windmill would't topple over, and further support at the base with holes for the electricity cables to go through
2.3. There was the possibility of the blades getting twisted back or falling off, so we decided to add further support by gluing sticks at the centre of the blade to the stalk
2.4. We added weights inside the base of the windmill because it fell over frequently
3. Constraints in Real Life
3.1. Monetary
3.1.1. Wind turbines under 100 kilowatts cost roughly $3,000 to $8,000 per kilowatt of capacity.
3.1.2. The costs for a utility scale wind turbine range from about $1.3 million to $2.2 million per MW of nameplate capacity installed.
3.1.3. It vary significantly depending on the number of turbines ordered, cost of financing, when the turbine purchase agreement was executed, construction contracts, the location of the project, and other factors
3.2. Time
3.2.1. We actually took a long time (around 4 weeks?) to make a tiny windmill. In real life, windmills need to be built rather quickly in order to produce more energy, so they can't each take a year to make, because there's a lot of them in the world that all require time and creation.
3.3. Physical Limitations
3.3.1. Typical modern wind turbines have diameters of 40 to 90 meters.
3.3.2. The widely used GE 1.5-megawatt model, for example, consists of 116-ft blades atop a 212-ft tower for a total height of 328 feet. The blades sweep a vertical airspace of just under an acre.
3.4. Manual Power
3.4.1. A lot of the times, there aren't enough people in the world to help watch over all the windmills, so they need to rather sturdy and independent in order to be effective. Our windmill isn't super effective, which means that it requires manual water and power a lot.
4. Use of windmills in the expansion of the American frontier.
4.1. The Brush wind turbine had a rotor 17 m (56 foot) in diameter and was mounted on an 18 m (60 foot) tower with 144 blades. It was 12 kW
4.2. In the American midwest between 1850 and 1900, a large number of small windmills, perhaps six million, were installed on farms to operate irrigation pumps.
4.3. By the 1930s windmills were widely used to generate electricity on farms in the United States where distribution systems had not yet been installed.
4.4. From 1974 through the mid-1980s the United States government worked with industry to advance the technology and enable large commercial wind turbines.
4.4.1. In the 1970s many people began to desire a self-sufficient life-style. Solar cells were too expensive for small-scale electrical generation, so some turned to windmills.
4.5. When oil prices declined by a factor of three from 1980 through the early 1990s, many turbine manufacturers, both large and small, left the business.
4.5.1. In the 1990s, as aesthetics and durability became more important, turbines were placed atop tubular steel or reinforced concrete towers.
4.6. Offshore wind power began to expand beyond fixed-bottom, shallow-water turbines beginning late in the first decade of the 2000s.
5. Stalk
5.1. The stalk was four sticks glued together, and it was pretty stable and able to hold all the blades up without wobbling
5.2. We had to attach the motor to the stalk, but we made it sort of slanted, so now there's a slight wobble when using it. We had to cut off part of the wood and add more; then we drilled another hole. This one worked much better.
5.3. It's around 50 cm tall, because we didn't want it too tall for the wind funnel, but it had to be tall enough for the blades and motor
5.4. The wobble from the first time really took up a lot of the energy that could have gone to producing electricity
5.4.1. The second hole we drilled was much straighter and the wobble was reduced as much as possible, though not eliminated completely
6. Base
6.1. It was four pieces of wood connected to each other and glued on both sides
6.2. It was to increase stability; also, we had to connect the electric cables to the motor and ensure the motor did not move with the stalk/blades moved
6.3. We drilled one large hole through the base, then we glued on another layer and drilled three holes through that layer to ensure we could connect the motor to something and ensure it was on flat and stable
7. The Four Power Transformations
7.1. Electricity--> Fan
7.1.1. We've seen the formula for determining the power in an electric circuit: by multiplying the voltage in "volts" by the current in "amps" we arrive at an answer in "watts
7.1.2. P (measured in volts) = E^2/R E = energy (voltage) R = resistance
7.2. Wind---> Blade
7.2.1. E(rotational)=½Iw ² I = inertia of rotating object w = angular velocity
7.2.1.1. windspeed: 15 mph
7.2.2. I = 1/12mL ² m = mass (20.1 g/0.0201 kg) L = length (44 cm/0.44 m)
7.2.3. w = 2π(RPM/60) RPM = rotations per minute RPM = 316
7.2.3.1. 79/450π mps
7.2.3.1.1. 0.5515240436 mps
7.2.4. P(rotation) = E/t P= [½(1/12mL ²)w ²] / s P= [½(1/12*0.2078 kg*0.44 m ²)2π(316/60)²] / s P =[½(1/12*0.2078 kg*0.44 m ²)33.10 ²] / s P = (1/2(0.00762²)(33.10²)/s P =(0.00002903)(1095.61)/s P=0.0318kg*m/s
7.3. Blade--> Motor
7.3.1. P=½ρAV³ P = power in watts ρ = The air density (1.2kg/m³ @ sea level and 20° C) A = The swept area of the turbine blades (m² square meters) V = wind speed ( meters per second)
7.3.2. P = 1.2 kg / m^3 A = 0.44 m * pi = 1.38 m^2 V =