System Design Review

1. System Design Review Power System for the Better Water Maker P14418

2. Agenda • Background • Problem Statement and Project Plan • Customer Needs and Engineering Requirements • Constraints and Design Drivers • Project Risk Assessment • System Analysis • House of Quality Results • Functional Decomposition • Pugh Analysis • Individual Concepts and Architectural Developments • Concept and Schematic • Risk Assessment • Initial Cost Estimate • Test Plan • Feedback

3. Problem Statement The Better Water Maker was developed to disinfect water in nations with high mortality rates due to poor water and sanitation systems. The goal of our team is to provide a low cost, efficient power generation system for the Better Water Maker that does not tire the user, while it is fun and easy to use.

4. Project Plan

5. Customer Needs (Critical) Primary needs • Generate adequate power • Is not tiring • Reduced cost • Maintain durability

6. Engineering Requirements • Generate 25 Watts • Can be used for at least 5 minutes • Costs less than $150 • Lasts for at least 180,000 gallons of water

7. Constraints & Design Drivers Key Design Drivers • Functionality, Reliability, Cost, Usability, Manufacturability • Durability, Efficiency Constraints • Cost, Size, Weight, Strength of User

8. System Analysis: HOQ Results Four highest weighted needs: • Ease of Repair • Cost • Unit Life • Effort Required

9. Functional Decomposition

10. Timing Diagram

11. General Process Flow Chart

12. Pugh Analysis

13. Pugh Analysis

14. Pugh Analysis

15. Solar Concept: Schematic Acquire Water Communicates Readiness to User Plug in BWM Hook up Battery Dispense Water

16. Engineering Analysis Assumptions: • 30W Solar Panel • Surface Area: 0.262 m^2 • Efficiency: 18% • 2-axis rotation • Clear-sky analysis • BWM requires 20.4-25.5W

19. Solar Insolation by Region

20. Port-au-Prince, Haiti Sun Chart: Hot Climate

21. Nepal Sun Chart: Cooler Climate

22. Calculations for 20° Latitude: Haiti • 8AM to 4PM availability • Shade drastically reduces power

23. Solar Concept: Risk Assessment By Importance • Reliability • Weather • Time • Shading • Theft • Battery • Shipping • Cost • Safety • Life • Additional Controls • Cost • Component

24. Solar Concept: Cost Analysis • 30W Monocrystalline Solar Panel 18V- $71.06 • 2-Axis Stand- $20-$30 • AC Converter- $20 • Wire extension- $10 • 12V lead acid battery - $30 Total Cost: ~$150 • May end up outside budget, but the system will provide power for any device.

25. Solar Concept: Test Plan • Use multimeter to verify the power. • Measure the power if a cell is shaded. • Collect data on battery charging capability. • Test ability of a child to use from start to finish. • Obtain a survey from users on its ease of use.

26. Leg-powered Concept • Recumbent Bicycle • Direct- or Chain-Drive

27. Leg-powered Concept: Schematic Current Generator Backrest Pedals Mounted on Crankshaft Seat 2x4 Bucket Pedals Mounted on Separate Sprockets Seat Current Generator

28. Risk Assessment • Large forces in system • More complicated setup • Reduced component life • Complex seating requirements

29. Function Accomplished Place User Generate Power Communicate to User Transfer Power Design Architecture Feature Seat Crank and Motors LEDs Wires, Chain, and Sprocket

30. Leg-powered Concept: Cost Analysis • Crankset - $10-20* • Pedals - $4* • Chain - $10 • Keyed Shaft - $10 -17* • Sprocket - $5 - 10 Chain Drive - $39 - 61 *Direct Drive - $24 - 41

31. Leg-powered Concept: Test Plan • Have volunteers test for comfort • Measures forces on seat and pedals • Can run for 5 minutes or more • Run generator while attached to a voltmeter • Ensure voltage is limited correctly

32. Spring Concept: Schematic Swing Single Jump Platform Double Jump Platform

33. Risk Assessment • Solenoids create heat • Proper heat sink • Springs could break • Properly constrained • Solenoid plunger must be correctly aligned • Prevent improper movement • Oscillations may be erratic • Use bridge rectifier

34. Spring Concept: Design Architecture Feature Casing/Spring Enclosure Solenoid Springs Rectifier Function Accomplished Place User Generate Power Facilitate Power Generation Regulate Power

35. Spring Concept: Cost Analysis • Springs - $3-10 each • Solenoid - $15-30 each • Rectifier - $0.50-3 • Plywood casing - $5-10 per setup • Rope/chain - $0.70/ft Swing - $30-68 Single Jump Platform - $26-63 Double Jump Platform - $52-123

36. Spring Concept: Test Plan • Test the components for each output individually • Verify with expectations • Test the ergonomics of the setup to determine whether it requires less effort than the original design • Bring children in to set up and use the apparatus • Use DOE tools to validate the testing results

37. Recommendations: • Solar Concept: • Has great potential, even beyond BWM, but has high risk in reliability and cost. • Leg-Powered Device • High reliability in combination with low cost and OTS components make this a desirable concept. • Spring Concept • Unknown reliability of power; this will need more anaysis before moving forward, but it has great potential to be fun and easy to use, as well as low in cost.

38. Questions and Comments?

39. Springs (Century Spring Corp.)

40. Solenoids (ElectroMechanics Online)

41. Rectifiers (Mouser Electronics)

42. Gravity Feed (not power generation)

43. Solar Power Supplement to Current BWM Design Pros: - Solar panel will reduce load on user - Redesign of current system may be minimal - Reduced learning curve for current users

44. Solar Power Supplement to Current BWM Design Cons: - Cloud cover and night- time eliminate the improvement - Solar panels are susceptible to theft

45. House of Quality