pedal purification university of notre dame senior design group a6 november 28, 2006 team rallye...
TRANSCRIPT
Pedal PurificationUniversity of Notre DameSenior Design Group A6November 28, 2006
Team Rallye (from left): Nicole Del Rey Eric Sabelhaus Mike McConnell Tim Rodts
Objective
• 2006 ASME Design Competition requirements:– Allow user to convert 200 mL of ‘polluted’ water into pure
drinking water within one hour. – Compact, collapsible, transportable design.
• Group Requirements:– Robustness - adaptable as power source for emergency
applications. – Collapsible – components housed underneath user’s seat when
not in operation.
The Concept
Pedals and
Gears
Generator Heating Condensing
Pedals and Gears
Pedals and
Gears
Generator Heating Condensing
Considerations: • User comfort (height adjustment with angle-iron)
• Sustainable user RPM• Optimum gear configuration
Generator
Pedals and
Gears
Generator Heating Condensing
Considerations:
• Sprocket mount to 5/16” generator shaft
-fitted sleeve and set-screw• Exposed wire
-wire caps• Connection to alternative power sources
-fitted to female plug•Firm mounting to base
-L-brackets mounted to wood base
Heating and Condensing
Pedals and
Gears
Generator Heating Condensing
Packaging
Pedals and
Gears
Generator Heating Condensing
Packaging
Compact
Expanded
Packaging
Pedals and
Gears
Generator Heating Condensing
Packaging
Features:
•Collapsible chair back•Fold-up angle-iron supports•All components housed underneath chair on stationary base
Concept
Realization
FEASIBILITY ISSUES
Feasibility Issue #1: Energy Requirements
Pavailable = 150 W
Eavailable= (150 W)(3600 s)
= 540 kJ
Erequired = ρcVΔT +mhfg
= 523 kJ
Question: Can a bicycle pedal system provide enough energy to boil 200 mL water in 1 hour?
Answer: YES – at 100% efficiency!
Feasibility Issue #2: Pressure Reduction
Erequired = Eheat +Evaporize + Evacuum
Emax = 523 kJ
Emin = 510 kJ
Question: Would a pressure reduction system be feasible for energy savings, since water boils at lower temperatures under lower pressures?
Answer: Energy savings are minimal, hence pressure reduction is infeasible.
Feasibility Issue #3: Maximizing Gear Ratio
• Question: How can generator power output be fully utilized?
• Generator: maximum 5,000 rpm at GR = 55.7
• Obtained: 460 rpm at GR = 5.13– Yields ≈ 3.0 W
• Result: Need 3 sets of sprockets (ratios shown below) to maximize generator power output.
• Deemed infeasible for prototype due to cost issues related to purchasing/mounting sprockets
• Answer: For final design,
increase gear ratio!
TECHNICAL ISSUES
Technical Issue #1: Generator Shaft/Sprocket Connection
• Generator can handle radial load, verified by supplier.• Sprocket with set-screw in hub necessary.• For ANSI Chain #35, minimum
½” bore diameter, generator
has 5/16” shaft.
• Solution: fashion sleeve
in sprocket/hub to
match shaft diameter.
Technical Issue #2: Compact Packaging
• Solution: CAD model to verify location/ orientation of components. – 21” x 25.5” between
chair legs– Condensing unit
– Removable Base
• In disassembled state, all components must be housed underneath chair to meet ASME requirements.– Maximum girth = 165”
– Prototype girth = 135”
Technical Issue #2: Compact Packaging
21”
11”
6”
11.8”25.4”
20”28
”
Technical Issue #3: Material Selection
• Material Requirements:
– Lightweight
– Strong
– Stiff
– Durable
• σapplied ≈ 3.8 MPa
• HDPE chosen
– Meets all requirements
– σHDPE – UTS ≈ 45 MPa
sectioncross
pedalhalf
applied A
F
Use of PrototypePedaling Demo
Voltage Output at 0.2 A
Sprockets in Motion
Condensing System
CONCLUSIONS
Conclusions• Prototype shows individual feasibility of:
– Mechanical energy transfer– Power Generation– Heating unit– Condensing unit
• Compact, collapsible and transportable design was achieved.
• Prototype proves feasibility while satisfying:– $400.00 budget– Design schedule
• Concept Design is feasible with modification to gear ratio.