1. ENGINEERING WORLD HEALTH: COLD BOX1
ENGINEERING WORLD HEALTH: COLD BOX
Josh Arenth
Cynthia Bien
Graham Gipson
Elise Springer
Brittany Wall
Group 19
Engineering World Health: Cold Box (Group 19)

2. ENGINEERING WORLD HEALTH2
ENGINEERING WORLD HEALTH
Organization background:
 Founded in 2001 by Dr Robert Malkin at Duke Univ.
 Charitable organization that collaborate with collegiate engineering programs
 Improves conditions of hospitals in developing nations
 Multi-step process:
(1) Assessment of hospitals (2) Ship container of refurbished medical equipment (3) Install equipment and train at location (4) Return to location to reinforce training
Engineering World Health: Cold Box (Group 19)

3. WHY WORK FOR EWH? Want to improve healthcare in developing countries3
WHY WORK FOR EWH?
Want to improve healthcare in developing countries
Impact the quality of healthcare in developing countries
 Give others an opportunity that was given to us
Engineering World Health: Cold Box (Group 19)

4. PROBLEM STATEMENT Build a portable device that:4
PROBLEM STATEMENT
Build a portable device that:
 Keeps a 5-mL fluid volume at 10°C (outside temperature 20°C) for up to 12 hours,
 Operates without electricity or outside fuel,
 Can be manufactured for less than $0.20 per unit (500 units for less than $100),
Does not require highly skilled labor to assemble.
Engineering World Health: Cold Box (Group 19)

5. 5
ASSESSMENT
 Determine a unique and efficient way to sustain 10°C for 12 hours
Will ice work?  CO2  Freon
 Decide which materials are good conductors and which are good insulators
 Ultimately determine which materials are both sufficient and cheap, and can be easily produced in the developing world
Engineering World Health: Cold Box (Group 19)

6. Initial Design: Prototype Cold Box Design Specs6
Initial Design: Prototype Cold Box Design Specs
Outer layer / casing Outer portion of container must be a good insulator (i.e., be an intrinsically poor conductor.) Ideal materials:  Styrofoam  Ceramic  Gas sandwiched between two layers Materials chosen:  Styrofoam with a durable plastic covering
Engineering World Health: Cold Box (Group 19)

7. Initial Design: Prototype Cold Box Design Specs7
Initial Design: Prototype Cold Box Design Specs
Heat sink Cold Box must have a component to remove heat from box contents Ideal materials:  Non-toxic, non-abrasive chemical reaction  Heat-absorbing material with large heat capacity Materials chosen:  Ice and water  Sodium bicarbonate / acetic acid system
Engineering World Health: Cold Box (Group 19)

8. Initial Design: Prototype Cold Box Design Specs8
Initial Design: Prototype Cold Box Design Specs
Inner casing Cold Box must have an inner layer to separate the contents of the box from heat-sink materials, yet still allow for efficient heat transfer (i.e., have high conductivity). Ideal materials:  Non-reactive metal  Glass Materials chosen:  Aluminum
Engineering World Health: Cold Box (Group 19)

9. Initial Design: Prototype Cold Box Design Specs9
Initial Design: Prototype Cold Box Design Specs
heat-conductive inner wall
heat sink
insulating outer wall
storage cavity
Schematic description
In the cold box, an endothermic chemical reaction (generalized here) consumes thermal energy, thus drawing heat out of the inner cavity. This heat is trapped in the heat sink because of the outer insulating boundary.
heat efflux
a + b + Δ → c
Engineering World Health: Cold Box (Group 19)

10. Initial Design: Prototype A10
Initial Design: Prototype A
Outer layer / casing: paper-plastic composite (mostly paper)
Inner-chamber layer: aluminum
Heat sink: Binary mixture described below
Cooling Technique: mixture of water (267mL), NaCl (10g), ice
Measuring Technique: LabWorks thermistor-based temperature probe
Engineering World Health: Cold Box (Group 19)

11. Initial Design: Prototype A11
Initial Design: Prototype A
Engineering World Health: Cold Box (Group 19)

12. Initial Design: Prototype A Data12
Initial Design: Prototype A Data
Duration where temperature stayed below 10 °C / 50 °F:
22 min for air, 24 min for vial
Problem: Must stay at temperature for 12 h
Engineering World Health: Cold Box (Group 19)

13. Initial Design: Prototype B13
Initial Design: Prototype B
Outer layer / casing: polystyrene-air-polystyrene sandwich
Sealants: Gorilla Glue and reflective duct tape
Inner-chamber layer: aluminum
Heat sink: Binary mixture described below
Cooling Technique: salt-ice bath [NaCl] = 0.48 M
Measuring Technique: LabWorks thermistor-based temperature probe
Engineering World Health: Cold Box (Group 19)

14. Initial Design: Prototype B14
Initial Design: Prototype B
Lid
Insulating tape
Inner chamber
Cooling mixture
Nested foam cups
Trapped air
Trapped air
Engineering World Health: Cold Box (Group 19)

15. Initial Design: Prototype B Data15
Initial Design: Prototype B Data
Duration where temperature stayed below 10 °C / 50 °F:
h for air ( % from previous)
h for vial ( % from previous)
Problem: Even with better insulation, must stay at temperature for 12 h
Engineering World Health: Cold Box (Group 19)

16. Initial Design: Prototype B Cost16
Initial Design: Prototype B Cost
Material
Cost
Cost Unit
Quantity
Styrofoam
$0.016
/cup 1
$0.02
$0.043
/lid
$0.04
Aluminum Can
/can
$0.00
Insulating Tape
$0.227
/yd
0.26
$0.06
Gorilla glue
$0.722
/oz
0.5
$0.36
Total cost for Prototype B: $0.48
Challenge: Amount is over double what one unit should cost.
Solution: Develop theoretical model to help maximize efficiency while minimizing necessary materials (and thus cost)
Engineering World Health: Cold Box (Group 19)

17. 17
PAST WORK
Finalized NCIIA proposal and began regular meeting with advisor.
Agreed on overall design approach: chemical reaction for cooling
Developed lab protocols and secured lab space
Designed and fabricated two prototypes (A and B) and collected data on their efficiency at cooling
Compiled cost data on materials
Engineering World Health: Cold Box (Group 19)

18. 18
CURRENT WORK
Creation of theoretical model for device using heat transport principles
Creation of theoretical predictions for most effective chemical heat sink using physical chemistry principles (reaction thermodynamics / colligative properties)
Awaiting reply from Dr Malkin regarding questions gathered in past presentations
Prototype C design
Engineering World Health: Cold Box (Group 19)

19. FUTURE WORK Fabrication of Prototype C Lab testing of Prototype C19
FUTURE WORK
Fabrication of Prototype C
Lab testing of Prototype C
Application of theoretical-model outcome to designs
Make appropriate changes to our design paradigm based on Dr Malkin’s response
Toy around with an easier way to manipulate polystyrene and increase its insulating efficiency
Engineering World Health: Cold Box (Group 19)

20. FUTURE WORK: Prototype C Extra thick insulating outer wall20
FUTURE WORK: Prototype C
Extra thick insulating outer wall
heat-conductive inner wall
insulating outer wall
storage cavity
Environmental heat sink
Storage-cavity heat sink
Engineering World Health: Cold Box (Group 19)