The Vending Machine. April 23, Olivia Juneau Logan Taylor Chris Hensel Michael Culley. Team 6 Class C1

Transcription

1 1 The Vending Machine April 23, 2009 Olivia Juneau Logan Taylor Chris Hensel Michael Culley Team 6 Class C1

2 2 OVERVIEW The project being conducted is to make a windmill out of household items that will generate enough electricity to power a small light bulb. The windmill must be able to fit within a 0.5m X 0.5m X 0.8 m box. There was no restriction on materials that could be used to create this windmill, so the group decided to make a windmill inside of a cardboard box with aluminum cans and Styrofoam as the fan which is connected to a generator made from copper wire and magnets by a shaft which is spun by two gears. The fan is powered by wind from a large fan on high speed. The team obtained the desired results in that the generator powered by the fan was able to keep the light lit. The experiment as a whole was very successful for the group. Introduction The objective of this project is to design a windmill that will generated enough power to light a small light bulb while being powered by a large fan on high speed. Also the windmill must be able to fit in a 0.5m X 0.5m X 0.8 m box. All materials combined to make this generator must have a combined cost of forty dollars or less. Once the group has a final design for the generator they will have to make calculations to tell the efficiency of the windmill. Background Wind energy has been in use for a long time, from the invention of sailing to today. Today we have planes that fly in air and many other applications one being windmills. Windmills were first used by farmers to grind grains, as an alternate to hand grinding. The technology grew from then to be applied in 1920 to generate electricity. Only in recent times has this technology been seen as important. With today as oil shortages and rumors of peak oil become more common, alternative energy has become an important subject, and wind turbines are an important part of this movement. Most low power wind turbines at 700kW can produce enough electricity for around 160 households annually. However with recent advancements in windmill technology 2.5MW machines and 5MW turbines are now in development, which would provide for over a thousand homes over the course of a year. An advantage of wind farms is that they are made up of many structures. Each of the structures have turbines on them which can be changed easily, which then allows for easy expansion when necessary. Having the fields organized this way takes away the reliance on just one generator. Wind farms can also be built extremely quickly; the construction process itself generally takes only six months. The idea of wind farms is pretty eco-friendly and cost efficient, so it makes sense that we should be switching to them as a source of electricity. DESIGN PROCESS The group s design process was fairly routine; the group started with a brainstorming session. From the brainstorming the group came up with what they thought was a design that would work. It consisted of a fan blade connected to a shaft that was connected to gears that spun a smaller shaft that rotated four magnets. The magnets were originally going to be rare earth magnets but the decision to order them was not early

3 3 enough so ceramic magnets were settled for. From this brainstorming idea the group immediacy went out and bought the supplies. The supplies consisted of 4 Canada dry cans, a cardboard box, a piece of Styrofoam, 2 shafts of different sizes, a set of gears, 1500 feet of 28 gauge copper wire, 2 ceramic magnets, and 2 hard drive magnets. The cans were cut into propeller shapes and glued into the piece of Styrofoam, which had been cut into a circular shape. Next, the fan was placed on the larger shaft, which also had the larger gear on it. The shaft and fan were then put into the cardboard box where they could spin freely once hit by the air from the large fan. The smaller shaft had the smaller gear placed on it as well as the set of magnets. This shaft was also stuck through the box where the rod was spun by the larger gear from the fan. The magnets on the rod were placed inside of a large coil of copper wire where the magnets spun perpendicular to that of the coil of wire. Device Description The generator was able to catch air very easily with the propellers from the large fan, and the gears worked very well to spin the magnets inside of the copper coil to generate electricity. The device is a cardboard box with shafts through it that spin gears. The lower gear and shaft have magnets connected to them that spin as the fan spins. That in turn makes the current in the coils.

4 4 ANALYSIS Power is kinetic energy (KE) divided by time (t), so the power generated by the fan is one half the mass density of air (ρ) times area of fan blade, A, times the length of the fan blade (L) times wind velocity, v, squared : KE = 1 / 2 ρ(l*a)v 2 Equation 1 Then you take the value from equation 1 and divide it by time (t). However for our calculations we took the equation for power and rewrote it as: P = 1 / 2 ρav 3 Equation 2 Using Equation 2, for a wind speed of approximately 20 miles per hour, 7.16 watts of power is produced. The windmill gets its power from that power. After testing our windmill the Vending Machine well got that it produces around 10 volts and an ampere of 140 milliamps. The wattage after testing was.55 watts. An actual value of electric power can be calculated by multiplying current (I), by voltage (V): P = IV Equation 3 From equation 3 we should have gotten wattage of 1.4 watts. From here we go into efficiency of our generator and fan. Efficiency is calculated by following the equation below:

5 5 Efficiency = η η =[(Actual)/(Calculated)] * 100 Equation 4 Taking equation 4 our windmill has an efficiency of about % Bill of Materials Material Cost 2x 6 x 2 x.5 ceramic magnets $4.13 2x computer hard drive magnets $ (free we already had them ) 1500ft 28-gauge copper/tin wire $15.00 Canada dry cups $0.50 ( free 99 for use took them from recycling ) Small brass rod $2.00 Large brass rod $2.50 Large gear $.79 Small gear $. 56 Miscellaneous $2.00 Total $39.98 we only spent $26.98 Conclusions The group was very successful in the end because the windmill was able to fit in the desired size box as well as create enough energy to light the light bulb. However, this success was not achieved by simply coming up with one idea and everything working perfectly. The group s first design was to put the generator inside of and oatmeal can rather than the cardboard box. This didn t work because the oatmeal can was to small to hold everything that needed to be inside of it. The group s design using the cardboard box turned out to be the design needed to meet the requirements of the project. The project was a great learning experience for the group. One thing that really helped working through this project was the cooperation in all aspects. The main thing that was learned form this project was sometimes your first design does not always work to the desired effect. However in the end the group s persistence paid off in a windmill that met all requirements and worked to perfection when presented in recitation. If the opportunity presented itself again the group would have done some things differently. For example, they would have done a little more research on how a generator works. However the group worked very well and put in approximately 10 hours a piece on this project and managed to come up with a very successful design that met all requirements.

6 6 Resources Needham, Joseph (1986). Science and Civilization in China: Volume 4, Physics and Physical Technology, Part 2, Mechanical Engineering. Taipei: Caves Books Ltd.