Supplementary Materials for: Lost Loops: 19th century thermosiphon ventilation and its potential for heat recovery in buildings today
Bibliographic record
Abstract
We investigate ventilation heat recovery with buoyancy flow, arranging interior spaces in an open thermal loop with heat exchange through partition walls. We draw inspiration from a Victorian-era thermosiphon scheme after finding it in Montreal’s former Royal Victoria Hospital and tracing the concept back to the original Centre Block of Canada’s Parliament Hill. We corroborate the archival evidence with analog models to visualize how the original hospital’s ventilation system worked. We use saline baths to verify how the siphon functioned and digital Schlieren to confirm how the full flow cycle worked with heat recovery. Then, to generalize these observations, we develop a mathematical model showing how heat recovery with buoyancy ventilation can work in simple room arrangements. We define a criterion for stable, unidirectional flow and a heat recovery efficiency limit of 50%. Finally, we validate the mathematical model experimentally, demonstrating stable, one-way flow close to the heat recovery limit.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.005 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.003 | 0.004 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.003 | 0.002 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.093 | 0.096 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".