Test protocol
- Freezing: all packs frozen about 24 hours; pulled at 3:00 p.m. Oct 3. Bulge measured first; infrared imaging from 4:00 p.m.
- Setting: packs on R-6 insulation board with plain sheets, no fans, air-conditioning grille closed, ambient near 73.6°F, two LED work lights.
- Imaging: rear face only, neck up. Every 15 minutes in the afternoon and evening, every 30 minutes after 1:15 a.m.
- Handling: packs flipped between reads so the rear face was up for imaging, which also tested how each pack handles movement.
- End rules: a pack is out of range when its average surface reaches 70°F, or when three consecutive reads are essentially the same (a stall, dated from the first of the three). The test runs until essentially all packs of a type are done or clearly on track to be.
- Records: the original images are never modified; outlines are drawn on copies. The raw data table is kept unaltered, with a separate working copy for analysis.
Packs and weights
All DuraTherm packs use the same commercial gel-pack shells as the controls, emptied and refilled. All test units were sealed with clear 100% silicone before freezing.
| Group | Packs | Exit weight, mean | Spread |
|---|
| Medium DuraTherm | 23 | 506.2 g | ±8.5 g |
| Medium gel (control) | 27 | 421.4 g | ±7.1 g |
| Small DuraTherm | 4 | 271.6 g | ±1.8 g |
| Small gel (control) | 6 | 224.5 g | ±11.1 g |
| Large DuraTherm | 1 | 1,346 g | – |
| Large gel (control) | 1 | 1,095 g | – |
- Water added to each new medium DuraTherm: 380.2 g ±0.6 g (within ±0.16% of the mean).
- DuraTherm's extra weight is cotton fiber and sealant, not extra water.
- Three medium DuraTherm packs were older "legacy" units with no borax, kept in to show long-term behavior.
Timeline and data gaps
Every gap is recorded rather than filled in. No values are interpolated.
- 3:00 p.m. packs out of the freezer; 4:00 p.m. first infrared read.
- 10:15 p.m. packs were flipped one extra time, then corrected before 10:30.
- 10:30 p.m. one set of six medium DuraTherm packs was not imaged.
- 11:45 p.m. one medium gel pack (17MC) was not imaged.
- 12:15 a.m. not imaged; packs re-imaged at about 12:24.
- 1:00 a.m. skipped; reads resumed at 1:15, then every 30 minutes.
- 4:00 a.m. missed.
- 5:00 a.m. final read. The test ended after this read, 14 hours after the packs left the freezer.
Data files
These records exist and are available to researchers, partners and investors on request:
- Original infrared images for every read, about 2,500 in all, plus the outlined copies.
- Per-read raw data tables: scale, center reading, whole face, five zones, spread and percent within ±3°F for every pack.
- The cross-read analysis workbook with formulas, group summaries and statistical tests.
- Four-view analysis panels for every pack at every fully analyzed read.
- Pack build records: dry, filled and exit weights.
- Video of the test and an audio narrative.
Ask by email: [email protected]
Replicate the test
- Buy two matching sets of the same commercial gel pack.
- Drill and empty one set, rinse each shell three times, and dry it fully.
- Fill the empty shells with cotton by weight, add water by weight with the scale tared, and seal.
- Freeze both sets together for 24 hours.
- Lay them out on insulation board in still air and record surface temperature at fixed times, always on the same face.
- Flip packs well before you measure them, not right before.