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8/3/2019 NiTi Project Junior Year
http://slidepdf.com/reader/full/niti-project-junior-year 1/16
Jared Vidales Austin Schader
Nick WiswellMichael Turovskiy
Aaron YourilKevin Wilkins
CooliNiTTM
8/3/2019 NiTi Project Junior Year
http://slidepdf.com/reader/full/niti-project-junior-year 2/16
Product Overviewy The product is a heat pump
using the unique propertiesof superelastic nitinol wire
yThe product functions bystraining the wire around aspool in one working fluidand allowing it to release inanother
y Advantages of the designinclude hand operation andportability
8/3/2019 NiTi Project Junior Year
http://slidepdf.com/reader/full/niti-project-junior-year 3/16
Science of Superelasticityy A f > Room Temperature
y Strain causes A M
y Harvest H of
transformation
y 5% Fatigue Limit
8/3/2019 NiTi Project Junior Year
http://slidepdf.com/reader/full/niti-project-junior-year 4/16
Heat
Pump Thermodynamics
Cycle of compressor-based heatpump
Heat pumps use work to move heat energybetween thermal reservoirs
A common example of a heat pump is a
household refrigerator
Traditional systems use a compressible fluidand two heat exchangers
Nitinol wire can be used to replace the fluid
because of its superelasticity; it has a thermalresponse to strain
8/3/2019 NiTi Project Junior Year
http://slidepdf.com/reader/full/niti-project-junior-year 5/16
Theoretical Efficiencyy The theoretical efficiency (measured as Coefficient of
Performance) of a traditional compressor-based heat pump isproportional to ambient temperature
y This will also apply to the wire as the ambient temperatureincreases; eventually the heat of transformation will be overcomeby the ambient temperature difference
y A nitinol-based system can have a COP larger than 1 because
work is stored in the strain of the wire; the limiting factor is thedifference in the elastic modulus of the austenite and martensite
8/3/2019 NiTi Project Junior Year
http://slidepdf.com/reader/full/niti-project-junior-year 6/16
Early Proof Calculations
Pure bending problem:
Wire is worst possible cross-section:
10% of wire strains >.08Ensuring bulk of wire getsstrained
Percent transformation:
Assume 100% phasetransformation at .08 strain
8/3/2019 NiTi Project Junior Year
http://slidepdf.com/reader/full/niti-project-junior-year 7/16
Early CalculationsOptimal radius of curvature:
Average strain of the inner 90%:
Percent transformed on bending:
Final energy yield on bending:
8/3/2019 NiTi Project Junior Year
http://slidepdf.com/reader/full/niti-project-junior-year 8/16
Preliminary TestingReleased strained Nitinol in ~50mL H2O
Measured T = -0.5 to -1ºC
8/3/2019 NiTi Project Junior Year
http://slidepdf.com/reader/full/niti-project-junior-year 9/16
Conceptual Designs
8/3/2019 NiTi Project Junior Year
http://slidepdf.com/reader/full/niti-project-junior-year 10/16
Prototype Sketch
8/3/2019 NiTi Project Junior Year
http://slidepdf.com/reader/full/niti-project-junior-year 11/16
Final Prototype
y Simple design
y Portable
yManually driven
y Low cost
y Repeatable
8/3/2019 NiTi Project Junior Year
http://slidepdf.com/reader/full/niti-project-junior-year 12/16
Markety Portable refrigeration
y Beverages
y Portable heating
y Beverage inserts
8/3/2019 NiTi Project Junior Year
http://slidepdf.com/reader/full/niti-project-junior-year 13/16
Manufacturing & Cost
Total cost = $25.00
ABS housing = $11.00
PVC Crank = $1.00
Wooden Dowel = $1.00
SE508 Nitinol 1mm = $12.00
8/3/2019 NiTi Project Junior Year
http://slidepdf.com/reader/full/niti-project-junior-year 14/16
Resultsy Results varied
y Many variables that could affect temperature change inthe water.
y Prototype itself
y Water clinging to NiTi
y Dowel
y Mechanical Heating
y Winding and Unwinding of NiTi
8/3/2019 NiTi Project Junior Year
http://slidepdf.com/reader/full/niti-project-junior-year 15/16
Future Improvements &Recommendations
y Convert to continuous system
y Material with greater insulating properties
y Larger volume of Nitinoly Greater diameter
y Longer wire