A Proposal to Design a Wind Turbine for Residential Use

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1 A Proposal to Design a Wind Turbine for Residential Use Submitted to Professor Richard L. Roberts February 7, 2011 by Caylee Johanson Zach Hallowell Greg Rolph Rob Sutton WENTWORTH INSTITUTE OF TECHNOLOGY MECH 578 Table of Contents Introduction & Summary As the demand for renewable energy emerges individuals are looking into the Earth s natural resources to benefit themselves and our future. Researchers have looked into solar power to harness energy, tidal currents in the oceans, but one of our most abundant natural resources is wind. With wind driven turbines we can harness the power of the wind and reapply that power to our homes. There are over 128 million homes in the United States alone that could be running off a source of renewable energy saving millions of dollars on the bills. In this project we plan to design a practical windmill for residential use to harness energy and reapply it to your house or even your electric car. We plan to design a type of windmill that is practical for residential use, yet affordable for an average Joe to buy. Most windmills you see today are build for larger applications unlike your home. With the proper research on windmills, wind speeds, regulations etc. we can analyze our data to determine the best possible windmill design for residential use.

2 Problem Definition In today s world the use for windmills is becoming greater and greater. You are starting to see windmills here and there, and in other locations you might find a whole wind farm but what about for the practical home owner. He/She doesn t have the need for a giant windmill on the side of there house nor can they afford a field of them. This is why we are looking to design a practical windmill for residential use that can harness energy, store it, and last applied to a house hold to reduce energy consumption or even supplement your electric bill. We will need to gather background information on every aspect of the project from the different types of windmills to the average household energy consumption. Our average energy consumption will be are base to work off of as this is the criteria we are trying to meet to supplement the cost of an average electric bill. We will also consider the geographical location of where the windmill will be installed along with legal regulations and zoning laws. Cost analysis will need to be made to determine the cost efficiency of buying your own residential windmill along with maintenance. With all of the proper research we will design a practical residential windmill. Literature Review & Background Research In 5000 B.C. wind was harnessed to propel boats down the Nile River and in 200 B.C. windmills pumped water in China and ground food in Persia. Through modern times wind turbines have evolved and in 2008 they generated 52 billion kwh or about 1.3% of the total U.S. electricity. Now there are several different designs of wind turbines which can be scaled for residential use. The two most common designs are the vertical axis and horizontal axis turbines which are pictured in Figure 1. These two designs both use blades to collect the kinetic energy of the wind. The blades are set at different angles or pitch depending on the turbine, and as the wind flows over them creating lift and causing them to turn. The blades are connected to a drive shaft which turns the generator as the blades turn.

3 Figure 1: Horizontal Axis and Vertical Axis Turbines Figure 2 shows several other designs that are being tested and modified for Urban use. These include the Energy Ball, the Windmaster, the Windside model, the AV Architectural model and the Aeroturbines model. Each of these turbines has a very unique design which makes use of different properties of energy generation. The Energy Ball collects the air within its spherical blades and makes use of the Venturi effect which states that as a fluid passes through a constricted area its pressure will decrease and its velocity will increase to satisfy conservation laws. Figure 2: Various Wind Turbine Designs for Urban Use In order to design a different wind turbine for residential use in the Northeast region of the United States we have begun to study the wind cycles and patterns and gather the average wind speeds of the region. The average wind speed for the Northeastern states varies from approximately mph. Information on these cycles and speeds may be referenced in the Appendices. Most turbines require a start up speed of 11 to 13 miles per hour. Since this speed is coincident with the average wind speed of the Northeast we want to design a turbine that has

4 lower start up speeds and can be used to generate a high percentage of residential energy during times when the wind isn t blowing as much. Other research that has to be done and taken into consideration in our design are the zoning laws of major cities and towns within the Northeast region, the average residential usage of energy, and how each turbine harnesses the wind. The Need Americans rely too much on non renewable energy. Most wind turbines that are meant for residential use, only need an average wind speed of around 11 to 13 miles per hour. In New England, all states have an average wind speed that meet the 11 mile an hour minimum. The average monthly electricity usage in New England is around 610 Kwh per month totaling 7320 Kwh per year. If someone were to add a wind turbine to their home to supplement their energy usage, they could potentially generate 13,000 Kwh per year. This means, conditions permitting, that someone could potentially make money off adding a turbine to their home by adding power back into the power grid. The Objective Our objective would be to create a small wind turbine that meets all laws and regulations of New England to supplement the average monthly electricity bill. We want to make a turbine that would be affordable to purchase and install, with a low maintenance cost, and wouldn't be unpleasant to have in your yard for you or your neighbors. The Work Plan There are several design specifications which mus be researchd including the power curve of wind turbines, wind source assessments, average energy used by a household, typical operatig temperatures and zoning laws. Since it has been decided to design a wind turbine efficient for use in the Northeast, these specifications may be researched. The next step is to research various types of wind turbines and how the aerodynamics of each wok. Things that must be taken into consideration include if air is deflected off the turbine and the wind power density. The Beltz Limit must also be taken into consideration which states that for a hypothetical ideal wind-extraction machine, the fundamental laws of conservation of mass and energy allow no more than 59.3% of the kinetic energy of wind to be captured (Schmidt). A typical model we will follow for the optimization of our turbine is seen in Figure 3.

5 Figure 3: Design Optimization Model (Schmidt) The input variables that will affect our design are: Average wind speed (11-13 mph) Weibull parameter (distribution of speed and % of time in region) Capital investment Fixed or variable speed rotor Blade coefficients of lift and drag at each wind speed Gearbox efficiency Generator efficiency Power electronics efficiency Price of electricity These inputs will then affect our outputs: Optimal rotor diameter Optimal generator capacity Optimal RPM for fixed speed design Optimal blade pitch at each wind speed Torque on gearbox at each wind speed Power produced at each wind speed Maximum total annual energy produced Our design will be modeled in Solidworks and simulations will be run to test these various inputs

6 and to measure the ouputs. The Qualifications Residential wind turbine systems have been designed, created and used successfully by many people who have chosen to produce their own systems. By studying and analyzing these residential systems, as well as large wind turbine systems, we will be able to build off of previously successful designs and ultimately design the most efficient system for our target application. We have access to many resources that will help us achieve our final goal of designing an efficient system for home use. We will use documented research and information to study important aspects of the project such as wind patterns in our target region (the northeastern US), average power consumption for average households, power storage systems (generators and batteries), electrical systems, materials for the turbine, housing, etc. The Budget This project is strictly a theoretical design project, therefore there is no budget. There will be no outside personnel hired; our group will be doing all of the work. All research will be done online and through books available in libraries. A wind turbine will not actually be built so no equipment or supplies will need to be purchased. The group already has access to Solidworks and any labs at the school if they become necessary. The Project s Future As stated previously, this project is strictly theoretical and no physical system will be produced at the projects completion. After completing our analysis and finalizing a design the next step in the project, if it were to be continued, would be actually building the wind turbine system. Prototypes would be built, tested and analyzed in real world situations until a final build design is decided upon. From here the design could be updated over time after long term use has occurred. Different models could be produced for even more specific applications (such as a city setting as opposed to rural, and so on). Bibliography "ESR - Table 5. Average Monthly Bill by Census Division, and State, 2008." U.S. Energy Information Administration - EIA - Independent Statistics and Analysis. Nov Web. 1 Feb < "EERE: Wind and Water Power Program Home Page." EERE: EERE Server Maintenance. Web. 17 Jan < "AMERICAN WIND ENERGY ASSOCIATION Learn About Wind Power Publications Fact Sheets." AMERICAN WIND ENERGY ASSOCIATION Welcome to AWEA. Web. 18 Jan

7 < "Urban Wind Electricity Generators." GETTING HOME ENERGY SAVINGS. Web. 21 Jan < "Residential Prices Total Energy Costs by State. Definition, Graph and Map." StateMaster - US Statistics, State Comparisons. Web. 21 Jan < ene_res_pri_tot_ene_cos-energy-residential-prices-total-costs>. "Electricity FAQs - Energy Information Administration." U.S. Energy Information Administration - EIA - Independent Statistics and Analysis. Web. 21 Jan < electricity_faqs.asp>. Schmidt, Michael. Wind Turbine Design Optimization. Georgia Institute of Technology Strategic Energy Institute. 4 Feb Appendices