1. G  Love Kristin Brodie Jeff Colton Colin Galbraith Bushra Makiya Tiffany Santos

2. Objective To create a glove that will generate heat to help keep your hand warm in a cold environment What will this require? Source of heat generation How will they be different? Lightweight Re-usable Smart Temperature Sensor/Switch Reversible Exothermic Material

3. Heat Loss Model Cylindrical Hand Power Lost @ -10  C relative to Power Lost @ 25  C 2  rLq = 2  L(T 1 -T 3 )/R = 2.5W R = Fabric Resistance + BL Resistance Conduction Convection Glove Layers

4. Overview Battery PoweredChecmical RechargeableNon-Rechargeable  Uses 2 ‘D’ batteries ReversibleNon-Reversible  Lasts 18 hours  One time use

5. Battery Operated Glove

6. Wires NiCr Alloys Stainless Steel Electrical Resistivity TestingMechanical Testing

7. Mechanical Testing Data NiCrNiCrFeFeCrNi Diameter (mm)0.410.380.404 Stress* (ksi)12074-130~95 Extension (in)1.952.163.5 *Expected Stress

8. Electrical Resistivity Testing All wire diameters are ~40mm *R for wire wrapped around a finger **R for wire after work-hardening

9. Wire Insulators Teflon PTFE Tubing PropertyUnitsValue Resistivity  cm 10 18 Tensile Strength MPa21-34 TmTm C327 Operating Temp C260 Water Absorption <0.01% Thermal Conductivity W/m  K 0.25 Teflon Tubing Nextel Braids

10. Batteries Amp  hr Size Durability Recharge ability Serial #603672141988597980 Discharge Capacity (Ah)0.7541.3641.181 Discharge Power (Wh)2.825.104.42 Length (mm)48.988.365.5 Width (mm)34.854.936.2 Height (mm)5.303.035.50 Final OCV (V)3.763.74 Final Impedance48.839.230.3

11. Field Testing At what temperature is your hand comfortable? Tested 10 subjects Placed in freezer Dressed in winter clothes Wore gloves with heating element 1.7W of power supplied Temp recorded when subject said their hand was warm Conclusion Thermal Switch should turn power off at ~32  C TestT glove (F)T environment (F) 191.3-1.1 290.4-0.7 389.4-1.3 493.1-1.8 589.8-1.2 692.0-0.4 784.70.1 891.7-1.6 991.6-1.1 1090.9-0.7 AVG90.5 My hand feels warm, stop recording

12. Temperature Sensor/Switch Resistance/Current Testing BimetallicPolymer Before SwitchAfter Switch Expected Temp (  C) 32 Actual Temp (  C)32  3 Voltage (V)3.74 Resistance (  ) 0>10 6 Current (A)0.430.0012 PICTURE HERE

13. Fabric Blends of Polyester/Cotton were tested Thermal Testing Input Power = 1.73 W 100cm of wire 3.7V Temperature inside and outside of glove measured 2  rLq=2  L(T 1 -T 3 )/R = 1.73 W L/R = 0.018 W/k Power required using 100P* under same conditions as slide 3: 4.95 W

14. Phase Change Materials Octadecane T m = 27.2° C T c = 16.5° C  H c = 283.5 J/g Hydrophobic Soft, waxy material Polyethylene Glycol (PEG) T m = 26.6° C T c = 9.8° C  H c = 151.0 J/g Extremely hydrophilic Soft, waxy material

15. Differential Scanning Calorimetery OctadecanePolyethylene Glycol (PEG)

16. PCM Encapsulation To prevent leakage from glove when PCM melts. Ideal Process Microspheres to maximize surface area Polypropylene (PP) /High Density Polyethylene (PE) Can be used to encapsulate microspheres Can be drawn into fibers Extrusion of PEG/PP: phase separation Complications Lack of Encapsulation Facilities Lack of Extrusion Facilities Different thermal properties of PEG and PE

17. Microsphere Fabrication Successfully produced both paraffin and octadecane microspheres. Complications Inefficiency of filtering process Large scale production

18. PCM Encapsulation Octadecane Ground particles embedded in base material. Polydimethyl Siloxane (PDMS) Resin Thermal conductivity = 0.002W/m*K 5g octadecane in 10ml (~7.5g) PDMS PEG Melting attempts failed. Heat sealed in bags. Low Density Polyethylene (LDPE) Thermal conductivity = 0.33W/m*K 7g of PEG in ~11g LDPE -(CH 2 -CH 2 )-

19. Comparison of PCMs Octadecane in PDMSPEG in PE Potential Heat: 2.36 J Actual Heat: 1.16 J Reduction in Efficiency: 51% Potential Heat: 0.66 J Actual Heat: 0.43 J Reduction in Efficiency: 35%

20. PCM Conclusions Octadecane is more efficient than PEG. Polyethylene is more efficient than PDMS. Future Recommendations Encapsulate octadecane in polyethylene. Extrusion

21. Power Generated Wire P = V 2 /R V = 3.74V, R = 8.3  1.7 W for 156 min Octadecane 5 g 1417 J 1.7 W for 12.5 min PEG 7 g 1057 J 1.7 W for 9.4 min

22. Field Testing Battery Powered Octadecane PEG

23. Assembly Connect wires to temp switch Connecting wires to battery Mechanical Strengthening of Contacts Discharge battery Encapsulation of PCM Fabrication of Gloves

24. Future Work Improvements Encapsulation process Incorporation of wire into glove Ease of access to recharge battery On/Off switch Insulation of Wire