Steady-state and transient thermal response of a field-scale geothermal thermosyphon with active condenser
Bibliographic record
Abstract
The study first experimentally investigates the effects of CO₂ filling-ratios, cooling fluid flowrate, and temperature on steady-state performance and thermal resistances in different zones of the system. Subsequently, a time-dependent model of the transient thermal response of various key parameters—heat transfer rate, temperatures, and thermal resistances—in different zones of the system was developed to characterize the first-order system. The thermal response of each zone is represented by an exponential function, establishing a relationship between the response time, the geometry, and the heat transfer phenomena specific to each zone. Each zone has its own time constant, defined as the time required for the average temperature of that zone to reach 63.2% of its steady-state value. Any deviation from this reference value, during operation, indicates anomalies such as fouling, frost formation, or component failures in the system. Results show that total thermal resistance of the GT is 2 to 4 times higher than that of the active condenser (HX). The active condenser’s resistance exceeds the evaporator and CO2-side-condenser sections by up to 3 and 7 times, respectively. Reducing the thermal resistance of the active condenser and the interface between the evaporator and the ground is crucial for enhancing GT performance. The study also provides a detailed insight into the transient regime of the thermosyphon, which is not available for real-scale systems in the literature. These findings not only identify the critical components influencing performance but also introduce a novel diagnostic method for detecting anomalies in GT-HRV systems based on deviations in zone-specific time constants.
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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 | 0.001 |
| 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".