Modifications to ASHRAE's sizing method for vertical ground heat exchangers
Bibliographic record
Abstract
The current article proposes modifications to the ASHRAE sizing equation for vertical ground heat exchangers. The proposed method uses the same three pulse approach as the current sizing equation but uses g-functions to calculate the effective ground thermal resistances. One key feature of the iterative methodology is the ability to calculate new g-functions as the geometry morphs during the solution process. Long-term g-functions are evaluated analytically using the finite line source (FLS) solution over borehole segments while so-called short-term g-functions are calculated based on a hybrid analytical/numerical method to account for the borehole thermal capacity. The current article examines three aspects of the proposed methodology. First, it is shown that the time-consuming evaluation of the full g-function curve, typically obtained by temporal superposition, is not necessarily required. Second, the optimum number of borehole segments to obtain an accurate bore field length with reasonable calculation time is examined. The selection of a convergence criteria and its impact on calculation time is also discussed. The excellent agreement between results obtained with the proposed alternative method and the ones obtained from other design software tools confirms the validity of the proposed method. Finally, it is shown that short-term effects can have a relatively significant effect on the calculation of the required borehole length.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 0.002 |
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".