19th-century thermosiphon ventilation and its potential for heat recovery in buildings today
Bibliographic record
Abstract
Summary A forgotten thermosiphon scheme is found in Montreal's former Royal Victoria Hospital and traced back to the original Center Block of Canada's Parliament Hill. This discovery inspires an investigation into the fluid mechanics of heat recovery with buoyancy ventilation, where interior spaces are arranged in an open thermal loop with heat exchange through partition walls. Flow visualizations with physical models are used to corroborate the archival evidence and show how the historical scheme worked. The scheme is then generalized, defining a criterion for steady unidirectional flow (λ>1) and a heat recovery limit when room temperatures upstream and downstream reach equilibrium (ε≤50%). This mathematical model is validated experimentally, demonstrating steady flow (λ∼2.21) close to the efficiency limit (ε∼0.40) with a balanced thermal design (NTU∼1) . Further analysis shows significant heating savings are possible in mildly cold seasons compared to natural displacement (74%) and natural mixing (60%) ventilation.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.002 | 0.008 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 0.000 |
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".