1. Brian Klimm Peter Ozols Tapan Patel Jeffrey Walsh Daniel West Capstone Design Northeastern University December 4, 2007

2. Problem Statement Design a wind powered system that will provide an energy source to an off the grid location Design an innovative system that incorporates power storage through a battery backup system providing 3 days of continuous use without recharging

3. Background: Product Niche & Economics Economics – Pros Eliminates utility bills Majority of cost is upfront in materials and construction Aboveground electric cables can be as much as $10 per ft – Cons Financial and land costs limit the market NIMBY, aesthetics play a factor Reason for Design – Desire to reduce one’s carbon footprint – 1kWh produced by wind turbine = 3.41 ft 3 of natural gas or 0.0034 gal of oil – Reduce or eliminate reliance on the power grid

4. Background: Market Options Small Wind Turbines range from 20 W to 100 kW Southwest Windpower – SkyStream 3.7 – Air Breeze – Air-X – Whisper 100 & 200 Bergey 50 kW 400 W 3 kW 10 kW

5. Selecting a Feasible Site Key Factors – Average wind speeds – Local regulations – Proximity to Northeastern Narrowed to Nantucket, Cape Cod and NUHOC Lodge – Nantucket was the only site that fit the 3 criterion Laws & Regulations – Zoning laws must be analyzed on a case-to-case basis – Nantucket, MA 60 ft tower height limit Guy wires may be no closer than 15 ft from property line Noise limitations Fence around tower Drawing package must be submitted to Town Council

8. Wind Power & Energy: Small Cabin Layout

9. Wind Power & Energy: Power Estimates for Cabin Layout AppliancesSpecificationsHow Often Used Number of Appliances Average kWh per monthTotal (kWh) Energy Star Compact Fluorescent Lights (100 Watt incandescent)28 Watts4 hrs./day73.3623.52 Ceiling Fan, high speed 12 hrs./day123.4 Energy Star Refrigerator/freezer17.5 cubic feet8 hr./day160 Microwave Oven 30 min./day112 Television, 32" LCD 6 hrs./day127 Coffee Maker 15 min./day111.25 Outlets 6 0 Washing Machine 8 loads/wk.180 Water Pump 0.5 hrs/day116.5 Total Monthly Power253.67 Total Yearly Power3044.04

10. V = Velocity in mph EPF = Energy Pattern Factor of 1.91 for a Rayleigh Distribution of wind speeds Power Density Based on Sea Level Conditions V = Velocity in mph EPF = Energy Pattern Factor of 1.91 for a Rayleigh Distribution of wind speeds Power Density Based on Sea Level Conditions AEO = Annual Energy Output P/A = Power Density P = Power in Wind A = Swept Area % Efficiency = Betz Limit and Turbine Components = 30% Swept Area r = length of a single blade Wind Power & Energy: Estimated Output

11. Wind Power & Energy: Estimated Wind Energy Output Assumptions: – Temperature15 C (59 F) – Air density1.225 kg/m 3 – Sea level pressure29.92 in Hg – Energy Pattern Factor1.91 – Swept Area3.58 (m 2 ) – Blade Length1.0668 (m) Design Site Annual Average Wind Speed mph Power Density W/m Annual Energy Density kWh/m 2 Overall Conversion Effciency % Annual Energy Output kWh/m 2 Nantucket, MA15.00352.732213.590.303314.02 2

12. Wind Power & Energy: Energy Output With Varied Blade Length

13. Wind System Components: Alternator Two commonly used options for wind powered generation – Induction Motor – Permanent Magnet Alternator Induction Motors need to be connected to the grid and require energy to start PMA requires no connection or power to start

14. Wind System Components: Rotor Blades More blades, more torque, slower speed Less blades, higher speeds, but reduced torque requiring higher winds Three blade design is most commonly used Offers best balance between start up speed and rotational speed.

15. Wind System Components: Rotor Blades Airfoil Design – Better performance – Higher price Drag Design – Easy to manufacture – Low price

16. Wind System Components: Rotor Blades Utilizes 3 blade design 7ft rotor diameter – TLG Wind Power 6061 T6 Aluminum rolled sheet metal

17. Wind System Components: Power Output At Nantucket’s average wind speed of 15 mph, the blades spin at 500 RPM At 500 RPM, the PMA produces 41 Volts at 9 Amps The resulting power is 369 Watts and 265 kWh per month

18. Off-the-Grid System GENERATOR BATTERIES INVERTER 3 phase AC AC LOADS (120 VAC 60Hz) WIND VARIABLE SPEED RECTIFIER CHARGE CONTROLLER DIVERSION LOAD DC

19. Wind System Components: Electrical System Diagram Electrical Power conversion and management components: –Southwest Windpower Charge Controller –Outback FX3048T Inverter

20. Wind System Components: Power Storage Configuration 48V 516Ah system – 8x 12V 258Ah Concorde PVX-2580L AGM lead acid batteries

21. Wind System Components: Proof of Concept Electrical Configuration

22. Wind System Components: Support Tower Height Strength Cost Footprint Monopole Tower Lattice Tower Guyed Tower

23. Wind System Components: Support Tower Southwest Windpower Air-X 45 Foot Tower – Includes all hardware excluding tubing and anchors – $210 for the kit, $2000 for the tubing and anchors – Instruction manual included

24. Conceptual Design Model

25. Proof of Concept Model

27. Questions?

28. Actual Cost

29. Prototype Cost

30. Background: Patent Search One of the first patents filed for a wind powered generator was in 1891 The system utilized a tail vane to direct the rotor into the wind and also a secondary battery to store the generated electricity

32. Nantucket Satellite Image

33. Structural Analysis