Transcritical CO2 refrigeration plants: Experimental campaign and model-based evaluations of new technologies
Bibliographic record
Abstract
The paper copes with a transcritical CO2 refrigeration plant: R744 (CO2) is an economic and natural refrigerant with a negligible impact on the environment and with good thermodynamic and safety properties compared to synthetic ones, and it is a sustainable alternative in commercial refrigeration of retail food. A specific 18 kWt test bench is available and under testing in the lab of the University of L’Aquila. Experimental tests were performed at different external temperatures between 8 °C and 33 °C: first results showed that COP (Coefficient Of Performance) decreases when external temperature grows up. Experimental data made it possible to calibrate a mathematical model of the test rig, useful to evaluate the effect of the possible introduction of new technologies: variation of receiver pressure, intercooled two-stage compression and expander in place of the high pressure throttling valve. All these technologies may be useful to improve plant efficiency and to promote new “green” installations in warmer climates, where food conservation standard in terms of goods cold-chain are increasingly demanding, especially considering EU and Global goals on HFC reduction targets (e.g. EU F-gas regulation - 2014 and Kigali amendment to the Montreal Protocol - 2016).
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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) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".