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ENGINEERING WORLD HEALTH: COLD BOX

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Presentation on theme: "ENGINEERING WORLD HEALTH: COLD BOX"— Presentation transcript:

1 ENGINEERING WORLD HEALTH: COLD BOX
1 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 HEALTH
2 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 countries
3 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 Specs
6 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 Specs
7 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 Specs
8 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 Specs
9 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 A
10 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 A
11 Initial Design: Prototype A Engineering World Health: Cold Box (Group 19)

12 Initial Design: Prototype A Data
12 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 B
13 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 B
14 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 Data
15 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 Cost
16 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 C
19 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 wall
20 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)


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