Carbon dioxide evaporation process in direct expansion geothermal boreholes
Bibliographic record
Abstract
Ground Heat Exchangers (GHE) play an important role in the performance of Ground Source Heat Pumps (GSHP).The impact is even more significant in direct expansion GSHP (DX-GSHP) systems as the refrigerant used in the heat pump also acts as the heat transfer fluid for the GHE.In this study, several experiments were carried out to investigate the performance of GHEs in a carbon dioxide (CO2) DX-GSHP.The evaporation of CO2 in the GHE was studied under various mass flow rates and number of active boreholes.For this purpose, a transcritical CO2 DX-GSHP test facility was built and fully equipped at CanmetENERGY-Varennes research laboratory.It was found that a partial two-phase flow regime along the GHE decreases the performance compared to the full two-phase flow and it has to be avoided for more efficient DX-GSHP systems.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".