GLove
Kristin Brodie
Jeff Colton
Colin Galbraith
Bushra Makiya
Tiffany Santos
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
Heat Loss Model



Cylindrical Hand
Power Lost @ -10C relative to Power Lost @ 25C
2rLq = 2L(T1-T3)/R = 2.5W

R = Fabric Resistance + BL Resistance
Glove Layers
Conduction
Convection
Overview
Battery Powered
Rechargeable
Non-Rechargeable
Uses
2 ‘D’ batteries
Checmical
Reversible
Non-Reversible
Lasts 18 hours
One time use
Battery Operated Glove
Wires
NiCr Alloys
Electrical Resistivity Testing
Stainless Steel
Mechanical Testing
Mechanical Testing Data
NiCr
Diameter (mm) 0.41
Stress* (ksi) 120
Stress vs Strain
for 3 wires
Extension (in) 1.95
Stress (lbs/in)
100000
80000
60000
40000
20000
0
0.005
0.01
0.015
Strain
NiCrFe
FeCrNi
NiCr
FeCrNi
0.38
0.404
74-130
~95
2.16
3.5
*Expected Stress
120000
0
NiCrFe
0.02
0.025
Electrical Resistivity Testing
Measured Resistances
0.1
Resistance ( W /cm)
0.09
0.08
0.07
0.06
0.05
0.04
0.03
0.02
0.01
0
Expected R
Measured R
R*
Condition
NiCr 80:20
All wire diameters are ~40mm
*R for wire wrapped around a finger
**R for wire after work-hardening
NiCrFe 60:16:24
FeCrNi 70:19:11
R**
Wire Insulators
Teflon Tubing
Nextel Braids
Teflon PTFE Tubing
Property
Units
Value
Resistivity
Wcm
1018
Tensile
Strength
MPa
21-34
Tm
C
327
Operating
Temp
C
260
Water
Absorption
Thermal
Conductivity
<0.01%
W/mK
0.25
Batteries




Amphr
Size
Durability
Recharge ability
Serial #
603672
141988
597980
Discharge Capacity (Ah)
0.754
1.364
1.181
Discharge Power (Wh)
2.82
5.10
4.42
Length (mm)
48.9
88.3
65.5
Width (mm)
34.8
54.9
36.2
Height (mm)
5.30
3.03
5.50
Final OCV (V)
3.76
3.74
3.74
Final Impedance
48.8
39.2
30.3
Field Testing
My hand feels warm,
stop recording
At what temperature is your hand
comfortable?
Test
1
Tested 10 subjects
2

Placed in freezer
3

Dressed in winter clothes

Wore gloves with heating element
4

1.7W of power supplied
5

Temp recorded when subject said their hand
6
was warm
7
Conclusion
8

Thermal Switch should turn power off at
9
~32C
10
AVG
Tglove(F)
Tenvironment(F)
91.3
-1.1
90.4
-0.7
89.4
-1.3
93.1
-1.8
89.8
-1.2
92.0
-0.4
84.7
0.1
91.7
-1.6
91.6
-1.1
90.9
-0.7
90.5
-1.0
Temperature Sensor/Switch
Bimetallic
Polymer
PICTURE HERE
Resistance/Current Testing
Before Switch After Switch
Expected Temp (C)
32
32  3
Actual Temp (C)
Voltage (V)
Resistance (W)
Current (A)
3.74
0
>106
0.43
0.0012
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(T1-T3)/R = 1.73 W
L/R = 0.018 W/k
Power required using 100P* under same conditions as slide 3: 4.95 W
Phase Change Materials






Octadecane
Tm = 27.2° C
Tc = 16.5° C
Hc = 283.5 J/g
Hydrophobic
Soft, waxy material






Polyethylene Glycol (PEG)
Tm = 26.6° C
Tc = 9.8° C
Hc = 151.0 J/g
Extremely hydrophilic
Soft, waxy material
Differential Scanning Calorimetery
Octadecane
Polyethylene Glycol (PEG)
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
Microsphere Fabrication


Successfully produced both paraffin and octadecane
microspheres.
Complications
 Inefficiency of filtering process
 Large scale production
PCM Encapsulation

Octadecane
 Ground particles embedded in
base material.
 Polydimethyl Siloxane (PDMS)
Resin
 Thermal conductivity =
0.002W/m*K

PEG
 Melting attempts failed.
 Heat sealed in bags.
 Low Density Polyethylene
(LDPE)
 Thermal conductivity =
0.33W/m*K
-(CH2-CH2)-

5g octadecane in 10ml (~7.5g)
PDMS

7g of PEG in ~11g LDPE
Comparison of PCMs
Octadecane in PDMS
PEG in PE
Potential Heat: 2.36 J
Actual Heat: 1.16 J
Potential Heat: 0.66 J
Actual Heat: 0.43 J
Reduction in Efficiency: 51%
Reduction in Efficiency: 35%
PCM Conclusions



Octadecane is more efficient than PEG.
Polyethylene is more efficient than PDMS.
Future Recommendations
 Encapsulate octadecane in polyethylene.
 Extrusion
Power Generated

Wire

P = V2/R

V = 3.74V, R = 8.3W

1.7 W for 156 min


Octadecane

5g

1417 J

1.7 W for 12.5 min
PEG

7g

1057 J

1.7 W for 9.4 min
Field Testing

Battery Powered

Octadecane

PEG
Assembly




Connect wires to temp switch
Connecting wires to battery
 Mechanical Strengthening of Contacts
 Discharge battery
Encapsulation of PCM
Fabrication of Gloves
Future Work

Improvements

Encapsulation process

Incorporation of wire into glove

Ease of access to recharge battery

On/Off switch

Insulation of Wire