This journal is a compilation of basic descriptions of the different
tests that the group conducted on their heat pipe, as well as the results, what
those results indicated to the group members, and the recorded data from each test organized in both
charts and graphs.
Test #1: 20 mL Water in "Harold" the Heat Pipe Prototype
 |
| One of the first tests using the 15 psi gauge at the top and only one thermocoupling. |
The first trial took place on Sunday morning April 24, 2016. The temperature
of the heat pipe was at this point only being measured at one location, farther
away from the initial heat source (hereafter also referred to as the far
location). The temperature of the heat pipe at the far location remained stable
at around room temperature for 1:30, before rising steadily. However, the
pressure gauge remained stagnant, and group members realized that the valve
from the heat pipe to the pressure gauge had been closed the night before had
not re-opened in the morning. As a result, the recorded data was thrown out,
and the trial re-started.
Test #2: 20 mL Water in "Harold"
This was another faulty trial. In between each test, it was necessary to
cool the pipe (and the heat transfer fluid within the pipe) back to room
temperature. Part of this process involved opening a vent on the side of the
heat gun. (Please keep in mind that it was still pretty early in the morning
and the group had gone to bed only a handful of hours before) The temperature
of the heat pipe was not rising, and within the first 45 seconds of the trial,
the group members realized that the vent on the side of the heat pipe was still
open. They closed it, erased the useless data, and began once again on their
testing.
Test #3: 20 mL Water in "Harold"
The third trial was a bit troubling, as all of the mechanisms were in the
correct positions, but the results were less useful than those of the test
conducted on Saturday night (before anyone started recording). The temperature
climbed more slowly than expected, but the real struggle came in when the 15
psi pressure gauge was maxed out within the first 3 minutes. The group decided
that 15 psi was not enough to measure the pressure up to, so switched the gauge
for one that maxed out at 30 psi instead. It was at this point that the group
also added the second thermocoupling, located closer to the heat gun (hereafter
the near reading).
Test #4: 20 mL Water in "Harold"
 |
| The group often referenced the Properties of Saturated Steam Table to see if the water was behaving as expected, which also helped to determine how accurate measurements were. |
Finally, with all of the stupid mistakes out of the
way, and a pressure
gauge more readily able to measure the amount of pressure the heat pipe
would
be dealing with, the group began their fourth trial of 20 mL of water.
Because
of the previous difficulties, and the fact that the heat pipe had in all
likelihood lost water overnight and during the change of gauges, this
trial was
not timed. Still, observations could be named, if not charted and
graphed. The temperature rose steadily. There was a first pressure pause
at 6.5 psi (on the gauge, which begins its measurement at 1 atm or
14.696 psi) and around 220°F. The group found a Properties of Saturated Steam Table
lying around in the basement, and had a good time referencing it as
they worked with the heat pipe. The temperature continued rising, but
paused again at 240°F.
The group had some concerns and attempted to troubleshoot during this
trial. To rid the system of air bubbles, the venting valve at the top
was opened, and a blowtorch was used to add more heat to the bottom of
the heat pipe, boiling the water inside and venting steam through the
top. The slower speed of the heat rising compared to the previous
night's trials led the group to properly evacuate the heat pipe and add
fresh water. While this was happening, a plain copper tube of about the
same length of the heat pipe was added, and both thermocouplings were
transferred sot that the group could establish a baseline test of the
heating speed of copper.
Test #5: Plain Length of Copper Tube
 |
| Above is the initial copper test where the copper tubing is not isolated from the vice. |
During
the first trial of plain copper tubing, the data indicated that there
was a drop in temperature at the beginning that didn't quite make sense
until someone pointed out that the vice holding the copper was made of
metal and could work as a heat sink. The group decided to run through 10
minutes worth of temperature data anyway, but run a second test to see
if it made any sort of significant difference in results. The
temperature rose slowly compared to even the more disappointing heat
pipe tests, which was encouraging to say the least.
| Time | Copper Near | Copper Far | ΔT Copper |
| 30 | 112 | 76 | 36 |
| 60 | 160 | 74.8 | 85.2 |
| 90 | 187 | 74.6 | 112.4 |
| 120 | 205 | 74.6 | 130.4 |
| 150 | 218 | 74.4 | 143.6 |
| 180 | 225 | 75 | 150 |
| 210 | 230 | 75 | 155 |
| 240 | 234 | 75.4 | 158.6 |
| 270 | 237 | 76 | 161 |
| 300 | 238 | 76.8 | 161.2 |
| 330 | 239 | 77 | 162 |
| 360 | 240 | 77.4 | 162.6 |
| 390 | 241 | 77.6 | 163.4 |
| 420 | 241 | 77.8 | 163.2 |
| 450 | 241 | 78 | 163 |
| 480 | 241 | 78.2 | 162.8 |
| 510 | 241 | 78.4 | 162.6 |
| 540 | 241 | 78.8 | 162.2 |
| 570 | 245 | 79 | 166 |
| 600 | 246 | 79 | 167 |
Test #6: Copper Baseline Take II (isolated from the vice using small pieces of oak)
The
second copper trial went smoothly. The heat gun was putting out
somewhere between 600°F and 700°F. The group once again cut the test off
at 10 minutes, feeling that there was enough information available to
create an accurate depiction of the heat transfer properties of copper
tubing by itself, isolated from the system. At the 10 minute mark, the
bottom of the system was at nearly 300°F, while the upper thermocoupling
read only 99.4°F. Even with the earlier heat pipe tests going
disappointingly, they were much faster, and hotter than the copper
alone. The temperature increased very steadily, almost linearly. Even
isolated, there was a temperature dip in the beginning of the
experiment. The group was not positive about why. Perhaps the pipe was
still cooling from the last experiment, or the wood soaked up some of
the initial heat.
| Time | Copper Near | Copper Far | ΔT Copper |
| 30 | 118 | 72.8 | 45.2 |
| 60 | 178 | 72.6 | 105.4 |
| 90 | 217 | 72.8 | 144.2 |
| 120 | 240 | 73.4 | 166.6 |
| 150 | 255 | 75 | 180 |
| 180 | 268 | 77 | 191 |
| 210 | 275 | 79.4 | 195.6 |
| 240 | 280 | 81.8 | 198.2 |
| 270 | 285 | 84.4 | 200.6 |
| 300 | 287 | 86.2 | 200.8 |
| 330 | 291 | 88 | 203 |
| 360 | 293 | 90 | 203 |
| 390 | 294 | 92 | 202 |
| 420 | 296 | 93.6 | 202.4 |
| 450 | 295 | 94.8 | 200.2 |
| 480 | 297 | 95.8 | 201.2 |
| 510 | 298 | 96.8 | 201.2 |
| 540 | 298 | 97.8 | 200.2 |
| 570 | 299 | 98.8 | 200.2 |
| 600 | 300 | 99.4 | 200.6 |
Test #7: 20mL (new) Water in "Harold"
After the previous tests, the group decided to have a fresh start, and drained the heat pipe and added fresh water. The test went well this time. Once again, the test was cut off at 30 psi instead of any time constraint, because of concerns about the solder joints failing and spewing hot water all across the room. It took about 00:10:30 to reach the cut-off point of 30 psi, and the temperature at the top of the heat pipe at that point was 270°F. According to the saturated steam tables, pressure should have been at about 41.85 psi, or according to our gauge 27.15 psi above 1 atm. This was about where we were, so all in all not a bad trial.
| Time | Water Near | Water Far | ΔT Water |
| 30 | 102 | 75.4 | 26.6 |
| 60 | 163 | 75.4 | 87.6 |
| 90 | 184 | 75.8 | 108.2 |
| 120 | 197 | 138.6 | 58.4 |
| 150 | 205 | 185.4 | 19.6 |
| 180 | 211 | 200.4 | 10.6 |
| 210 | 214 | 208.8 | 5.2 |
| 240 | 219 | 213.6 | 5.4 |
| 270 | 222 | 218.2 | 3.8 |
| 300 | 226 | 221.8 | 4.2 |
| 330 | 229 | 225.2 | 3.8 |
| 360 | 234 | 229.8 | 4.2 |
| 390 | 240 | 235 | 5 |
| 420 | 243 | 238.8 | 4.2 |
| 450 | 246 | 244.4 | 1.6 |
| 480 | 253 | 249.6 | 3.4 |
| 510 | 258 | 254 | 4 |
| 540 | 262 | 258 | 4 |
| 570 | 266 | 262.8 | 3.2 |
| 600 | 271 | 267 | 4 |
| 630 | 274 | 270.6 | 3.4 |
Test #8: 20 mL Methanol in "Harold"
There were concerns this round of testing, because during the bleeding process, the pressure spiked to 5 psi within 30 seconds of exposure to the blowtorch, so the process had to be watched much more carefully. The heat transfer was better than copper alone, and a little bit quicker than water, but the pressure rose so quickly that the trial had to be stopped in less than 10 minutes, and the temperature maxed out at 201.8°F at the top of the pipe and 216°F near the heat source, which is considerably lower than the 270°F that water reached during the trial. By the end of the test, we decided as a group to not use methanol in the final product.
 | |||
| Karen donned the only safety mask, because she was the closest to the heat pipe | . |
| Time | Methanol Near | Methanol Far | ΔT Methanol |
| 0 | 103 | 69 | 34 |
| 30 | 146 | 70 | 76 |
| 60 | 155 | 129.8 | 25.2 |
| 90 | 167 | 154.6 | 12.4 |
| 120 | 173 | 164.4 | 8.6 |
| 150 | 177 | 168 | 9 |
| 180 | 181 | 171.2 | 9.8 |
| 210 | 186 | 175.4 | 10.6 |
| 240 | 193 | 181.2 | 11.8 |
| 270 | 201 | 188.2 | 12.8 |
| 300 | 205 | 195 | 10 |
| 330 | 216 | 201.8 | 14.2 |
Test #9: 20 mL Acetone in "Harold"
Acetone also rose in pressure with impressive speed, which was a bit nerve-wracking. At about 30 psi, the trial was stopped. The temperature at the farther thermocoupling was 192.4°F, which was also much lower than the maximum heat for the 20mL of water. In addition to this, both acetone and methanol are fluids that you really don't want to accidentally spill into your ham, so at this point the group made a decision to use water in the final product instead of either of these two fluids. Someone suggested that the group purchase some 25/75% mixture of ammonia and water, as that is what's used in more industrial settings, but the group is unsure of whether or not they will be doing that.
| Time | Temp Near | Temp Far | ΔT |
| 0 | 68 | 70.4 | -2.4 |
| 30 | 106 | 70.2 | 35.8 |
| 60 | 131 | 105.6 | 25.4 |
| 90 | 142 | 132 | 10 |
| 120 | 152 | 142 | 10 |
| 150 | 163 | 152.4 | 10.6 |
| 180 | 175 | 163 | 12 |
| 210 | 188 | 170.4 | 17.6 |
| 240 | 196 | 177.8 | 18.2 |
| 270 | 206 | 185.6 | 20.4 |
| 300 | 216 | 192.4 | 23.6 |
Trial #10: 25 mL Water in "Harold"
The group had really only guessed at the 20mL, assuming that it was a decent trial amount as it filled the majority of the "well" at the bottom of the heat pipe (the name we used for the wider, evaporator end of the pipe). The 25mL trial went swimmingly. It was the first trial to actually have a higher temperature at the top of the pipe than the bottom of the pipe, which was pretty exciting.
| Time | Temp. Near | Temp. Far | ΔT |
| 0 | 85.0 | 84 | 1.0 |
| 30 | 110.0 | 84 | 26.0 |
| 60 | 133.8 | 83 | 50.8 |
| 90 | 151.0 | 83 | 68.0 |
| 120 | 161.1 | 92 | 69.1 |
| 150 | 173.8 | 149 | 24.8 |
| 180 | 180.8 | 168 | 12.8 |
| 210 | 186.2 | 182 | 4.2 |
| 240 | 191.8 | 176 | 15.8 |
| 270 | 195.0 | 190 | 5.0 |
| 300 | 201.2 | 197 | 4.2 |
| 330 | 208.6 | 206 | 2.6 |
| 360 | 214.8 | 213 | 1.8 |
| 390 | 219.8 | 220 | -0.2 |
| 420 | 223.4 | 225 | -1.6 |
| 450 | 227.2 | 229 | -1.8 |
| 480 | 230.4 | 232 | -1.6 |
| 510 | 233.4 | 235 | -1.6 |
| 540 | 236.4 | 238 | -1.6 |
| 570 | 238.8 | 241 | -2.2 |
| 600 | 242.2 | 244 | -1.8 |
| 630 | 245.0 | 247 | -2.0 |
| 660 | 247.6 | 250 | -2.4 |
| 690 | 250.6 | 253 | -2.4 |
| 720 | 253.4 | 254 | -0.6 |
| 750 | 255.4 | 257 | -1.6 |
| 780 | 257.6 | 259 | -1.4 |
| 810 | 259.8 | 261 | -1.2 |
| 840 | 261.8 | 262 | -0.2 |
| 870 | 263.6 | 264 | -0.4 |
| 900 | 265.2 | 268 | -2.8 |
| 930 | 266.8 | 268 | -1.2 |
No comments:
Post a Comment