A dynamic model of a vertical direct expansion ground heat exchanger
Bibliographic record
Abstract
The paper presents a general distributed model of a vertical U-tube direct expansion heat exchanger coupled with the ground. This model is developed for studying the dynamic thermal behavior of a buried heat exchanger (the evaporator or condenser) which is an integral part of the so-called direct expansion heat pump. The transient conservative equations of mass and energy considering the two-phase flow of refrigerant are derived and presented. The heat exchange with the ground is treated using an analytical approach to treat short time response of vertical boreholes based on an imposed heat flux. The thermal interference between the two pipes of the heat exchanger is also considered. The mathematical equations of the model are numerically presented using a finite difference scheme and the solution of the system of equations is obtained using a built-in iterative solver function of MatLab®. The dynamic behavior of a condenser and an evaporator are first obtained by imposing a change of the inlet conditions. Experimental data from a test rig are used to demonstrate the validity of the dynamic model
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 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 | 0.001 | 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) | 0.000 | 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 teacher head, 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".