Nerri1029
08-03-2007, 08:32 AM
Heat Pack Research Project
Mike Lawliss (aka Nerri1029)
Purpose:
To compare the effect of wrapping a heat pack in foil to limit Oxygen, and the effect of a heat sink (the Gel-Pack ) on the effectiveness of a heat pack in a cool weather packing situation for 48 hours.
Method and Procedures:
- Three Styrofoam boxes were used. They were identical in all dimensions. ( see Fig 1)
- Four stainless steel thermometer probes were used with the Vernier Logger-Pro© Software and Lab-Pro © Interface. One thermometer for each box and a fourth to measure the ambient temperature. ( see Fig 2)
- The Heat Packs were all from the same manufacturer and lot. ( 24hr heat packs made by Handwarmer.com) ( see Fig 4)
The expiration date for each heat pack was 7/31/2010. and the lot number was G628.
The Heat Packs each had a mass of just under 70g.
The Heat Packs were opened within seconds of each other and placed in the boxes as quickly as possible.
- The gel pack was sold by Moore Medical Co. and had a mass of 390g.
With dimensions of 16.51 cm x 19.96 cm ( see Fig 5)
- The foil was standard thickness with two small holes punched in each side. ( see Fig 6)
The edges of the foil were rolled and flattened to ensure an airtight seal. The holes measured approx. 2mm x 3mm
- Efforts were made to attempt identical placement of thermometer and heat packs. ( see Fig 7a,7b & 7c)
- The temperature was measured once every 15 minutes for 48 hours, and graphed. ( see Fig 3, Table 1)
Fig 1
http://i30.photobucket.com/albums/c334/TalulasFigNewton/MechMom/Fig1.jpg
Identical Styrofoam Boxes
Fig 2
http://i30.photobucket.com/albums/c334/TalulasFigNewton/MechMom/Fig2.jpg
Vernier Lab Interface with Stainless Steel Thermometers
Fig 4
http://i30.photobucket.com/albums/c334/TalulasFigNewton/MechMom/Fig4.jpg
Same package, same Lot Number, etc..
Fig 5
http://i30.photobucket.com/albums/c334/TalulasFigNewton/MechMom/Fig5.jpg
390 gram Gel-Pack.
Fig 6
http://i30.photobucket.com/albums/c334/TalulasFigNewton/MechMom/Fig6.jpg
One of the four holes poked into the foil. 2 per side.
Fig 7a,7b & 7c
http://i30.photobucket.com/albums/c334/TalulasFigNewton/MechMom/FIg7a.jpg
http://i30.photobucket.com/albums/c334/TalulasFigNewton/MechMom/Fig7b.jpg
http://i30.photobucket.com/albums/c334/TalulasFigNewton/MechMom/Fig7c.jpg
Identical Setups
Data (condensed from 4 readings/hr to 1 reading/hr):
Fig 3
http://i30.photobucket.com/albums/c334/TalulasFigNewton/MechMom/Fig3.gif
Temp 1 HEAT PACK ONLY
Temp 2 HEAT PACK + GEL PACK
Temp 3 HEAT PACK WRAPPED in FOIL
Temp 4 AMBIENT
Time (hr) Box 1 (°C) Box 2 (°C) Box 3 (°C) Amb (°C)
0.00 20.04 20.20 20.09 19.47
1.00 26.66 22.85 21.10 19.26
2.00 26.56 23.76 21.35 19.43
3.00 25.94 24.31 21.47 19.59
4.00 25.40 24.52 21.40 19.47
5.00 24.94 24.52 21.26 19.26
6.00 24.59 24.41 21.10 19.17
7.00 24.13 24.13 20.77 18.79
8.00 23.87 23.89 20.58 18.64
9.00 23.73 23.71 20.56 18.76
10.00 23.62 23.55 20.51 18.74
11.00 23.45 23.38 20.44 18.64
12.00 23.31 23.22 20.37 18.41
13.00 23.24 23.08 20.32 18.48
14.00 23.17 22.94 20.23 18.45
15.00 23.06 22.80 20.18 18.31
16.00 22.96 22.66 20.06 18.29
17.00 22.85 22.57 20.02 18.19
18.00 22.75 22.48 19.97 18.07
19.00 22.64 22.38 19.92 18.12
20.00 22.52 22.27 19.80 17.95
21.00 22.43 22.15 19.76 17.91
22.00 22.34 22.08 19.66 17.74
23.00 22.27 21.99 19.61 17.86
24.00 22.34 22.06 19.87 18.07
25.00 22.36 22.06 19.97 18.14
26.00 22.34 22.06 20.02 18.19
27.00 22.41 22.08 20.13 18.29
28.00 22.36 22.06 20.11 18.29
29.00 22.31 22.03 20.09 18.26
30.00 22.27 21.99 20.02 18.24
31.00 22.13 21.89 19.87 18.07
32.00 22.03 21.85 19.85 18.07
33.00 21.99 21.80 19.83 18.02
34.00 21.92 21.78 19.85 18.14
35.00 21.82 21.70 19.78 18.02
36.00 21.66 21.63 19.71 17.88
37.00 21.52 21.54 19.64 17.88
38.00 21.38 21.47 19.59 17.74
39.00 21.21 21.38 19.52 17.79
40.00 21.03 21.28 19.45 17.71
41.00 20.89 21.19 19.38 17.59
42.00 20.77 21.07 19.31 17.45
43.00 20.49 20.96 19.19 17.36
44.00 20.13 20.82 19.05 17.16
45.00 19.80 20.65 18.91 17.07
46.00 19.66 20.60 18.91 17.14
47.00 19.64 20.67 19.24 17.50
48.00 19.73 20.77 19.54 17.91
Discussion:
The data shows a definite effect from both the foil and the heat sink. The heat sink kept the temperature from spiking in the first hour, but after that the temperature of the plain heat pack and the one with the gel pack followed a similar path until hour 40. It was around hour 40 that the plain pack box cooled to a lower temperature. While the gel pack box retained heat for a longer period.
The foil wrapped pack did not attain the high temperatures of either of the two other packs, but did steadily maintain the temperature 2 degrees above ambient for the entire length of the experiment.
Conclusions and Questions:
The effect of the heat sink was easily seen both in the start of the experiment and at the end.
The larger mass had the ability to keep the initial spike of temperature down and it helped maintain the temp for a longer period of time after the heat pack had worn off.
The effect from the foil wrapping was not conclusive as other questions arose while the experiment was proceeding. How would the effects change with different sized holes in the foil, or with a greater number of holes put in the foil.?
It appeared that the foil wrapped pack was still giving off heat after the plain pack had stopped. A steady 2 Celsius degrees above ambient was observed for the entire sampling time.
“How much longer would the heat pack release heat at this slowed pace?”
One question hit me after examining the data: “What would a graph of a thermometer in a Styrofoam Box without a heat pack look like compared to ambient?”
And
“What would the graphs look like if the ambient temperature was 10 degrees to 15 degrees cooler?”
“Did closing the lids limit the supply of oxygen thus changing the effectiveness of the heat packs?”
My conclusion is that the practice of heat sinking works.
The duration of this experiment should cover length of time for many cool weather shipments sent overnight. Even with a delay, the temps should hold within a range. The heat sink would prevent the initial temps from rising too high, possibly hurting the cargo. The foil method may provide lengthier heating times than that posted on the heat pack’s label.
As for the oxygen content in the box, further testing should be done. Though anyone using carboard boxes with foam peanuts won’t have an issue unless the box is taped to be airtight.
Bibliography:
Data collected and graphs produced using Logger Pro © by Vernier Software
Mike Lawliss (aka Nerri1029)
Purpose:
To compare the effect of wrapping a heat pack in foil to limit Oxygen, and the effect of a heat sink (the Gel-Pack ) on the effectiveness of a heat pack in a cool weather packing situation for 48 hours.
Method and Procedures:
- Three Styrofoam boxes were used. They were identical in all dimensions. ( see Fig 1)
- Four stainless steel thermometer probes were used with the Vernier Logger-Pro© Software and Lab-Pro © Interface. One thermometer for each box and a fourth to measure the ambient temperature. ( see Fig 2)
- The Heat Packs were all from the same manufacturer and lot. ( 24hr heat packs made by Handwarmer.com) ( see Fig 4)
The expiration date for each heat pack was 7/31/2010. and the lot number was G628.
The Heat Packs each had a mass of just under 70g.
The Heat Packs were opened within seconds of each other and placed in the boxes as quickly as possible.
- The gel pack was sold by Moore Medical Co. and had a mass of 390g.
With dimensions of 16.51 cm x 19.96 cm ( see Fig 5)
- The foil was standard thickness with two small holes punched in each side. ( see Fig 6)
The edges of the foil were rolled and flattened to ensure an airtight seal. The holes measured approx. 2mm x 3mm
- Efforts were made to attempt identical placement of thermometer and heat packs. ( see Fig 7a,7b & 7c)
- The temperature was measured once every 15 minutes for 48 hours, and graphed. ( see Fig 3, Table 1)
Fig 1
http://i30.photobucket.com/albums/c334/TalulasFigNewton/MechMom/Fig1.jpg
Identical Styrofoam Boxes
Fig 2
http://i30.photobucket.com/albums/c334/TalulasFigNewton/MechMom/Fig2.jpg
Vernier Lab Interface with Stainless Steel Thermometers
Fig 4
http://i30.photobucket.com/albums/c334/TalulasFigNewton/MechMom/Fig4.jpg
Same package, same Lot Number, etc..
Fig 5
http://i30.photobucket.com/albums/c334/TalulasFigNewton/MechMom/Fig5.jpg
390 gram Gel-Pack.
Fig 6
http://i30.photobucket.com/albums/c334/TalulasFigNewton/MechMom/Fig6.jpg
One of the four holes poked into the foil. 2 per side.
Fig 7a,7b & 7c
http://i30.photobucket.com/albums/c334/TalulasFigNewton/MechMom/FIg7a.jpg
http://i30.photobucket.com/albums/c334/TalulasFigNewton/MechMom/Fig7b.jpg
http://i30.photobucket.com/albums/c334/TalulasFigNewton/MechMom/Fig7c.jpg
Identical Setups
Data (condensed from 4 readings/hr to 1 reading/hr):
Fig 3
http://i30.photobucket.com/albums/c334/TalulasFigNewton/MechMom/Fig3.gif
Temp 1 HEAT PACK ONLY
Temp 2 HEAT PACK + GEL PACK
Temp 3 HEAT PACK WRAPPED in FOIL
Temp 4 AMBIENT
Time (hr) Box 1 (°C) Box 2 (°C) Box 3 (°C) Amb (°C)
0.00 20.04 20.20 20.09 19.47
1.00 26.66 22.85 21.10 19.26
2.00 26.56 23.76 21.35 19.43
3.00 25.94 24.31 21.47 19.59
4.00 25.40 24.52 21.40 19.47
5.00 24.94 24.52 21.26 19.26
6.00 24.59 24.41 21.10 19.17
7.00 24.13 24.13 20.77 18.79
8.00 23.87 23.89 20.58 18.64
9.00 23.73 23.71 20.56 18.76
10.00 23.62 23.55 20.51 18.74
11.00 23.45 23.38 20.44 18.64
12.00 23.31 23.22 20.37 18.41
13.00 23.24 23.08 20.32 18.48
14.00 23.17 22.94 20.23 18.45
15.00 23.06 22.80 20.18 18.31
16.00 22.96 22.66 20.06 18.29
17.00 22.85 22.57 20.02 18.19
18.00 22.75 22.48 19.97 18.07
19.00 22.64 22.38 19.92 18.12
20.00 22.52 22.27 19.80 17.95
21.00 22.43 22.15 19.76 17.91
22.00 22.34 22.08 19.66 17.74
23.00 22.27 21.99 19.61 17.86
24.00 22.34 22.06 19.87 18.07
25.00 22.36 22.06 19.97 18.14
26.00 22.34 22.06 20.02 18.19
27.00 22.41 22.08 20.13 18.29
28.00 22.36 22.06 20.11 18.29
29.00 22.31 22.03 20.09 18.26
30.00 22.27 21.99 20.02 18.24
31.00 22.13 21.89 19.87 18.07
32.00 22.03 21.85 19.85 18.07
33.00 21.99 21.80 19.83 18.02
34.00 21.92 21.78 19.85 18.14
35.00 21.82 21.70 19.78 18.02
36.00 21.66 21.63 19.71 17.88
37.00 21.52 21.54 19.64 17.88
38.00 21.38 21.47 19.59 17.74
39.00 21.21 21.38 19.52 17.79
40.00 21.03 21.28 19.45 17.71
41.00 20.89 21.19 19.38 17.59
42.00 20.77 21.07 19.31 17.45
43.00 20.49 20.96 19.19 17.36
44.00 20.13 20.82 19.05 17.16
45.00 19.80 20.65 18.91 17.07
46.00 19.66 20.60 18.91 17.14
47.00 19.64 20.67 19.24 17.50
48.00 19.73 20.77 19.54 17.91
Discussion:
The data shows a definite effect from both the foil and the heat sink. The heat sink kept the temperature from spiking in the first hour, but after that the temperature of the plain heat pack and the one with the gel pack followed a similar path until hour 40. It was around hour 40 that the plain pack box cooled to a lower temperature. While the gel pack box retained heat for a longer period.
The foil wrapped pack did not attain the high temperatures of either of the two other packs, but did steadily maintain the temperature 2 degrees above ambient for the entire length of the experiment.
Conclusions and Questions:
The effect of the heat sink was easily seen both in the start of the experiment and at the end.
The larger mass had the ability to keep the initial spike of temperature down and it helped maintain the temp for a longer period of time after the heat pack had worn off.
The effect from the foil wrapping was not conclusive as other questions arose while the experiment was proceeding. How would the effects change with different sized holes in the foil, or with a greater number of holes put in the foil.?
It appeared that the foil wrapped pack was still giving off heat after the plain pack had stopped. A steady 2 Celsius degrees above ambient was observed for the entire sampling time.
“How much longer would the heat pack release heat at this slowed pace?”
One question hit me after examining the data: “What would a graph of a thermometer in a Styrofoam Box without a heat pack look like compared to ambient?”
And
“What would the graphs look like if the ambient temperature was 10 degrees to 15 degrees cooler?”
“Did closing the lids limit the supply of oxygen thus changing the effectiveness of the heat packs?”
My conclusion is that the practice of heat sinking works.
The duration of this experiment should cover length of time for many cool weather shipments sent overnight. Even with a delay, the temps should hold within a range. The heat sink would prevent the initial temps from rising too high, possibly hurting the cargo. The foil method may provide lengthier heating times than that posted on the heat pack’s label.
As for the oxygen content in the box, further testing should be done. Though anyone using carboard boxes with foam peanuts won’t have an issue unless the box is taped to be airtight.
Bibliography:
Data collected and graphs produced using Logger Pro © by Vernier Software