Heat Transfer Comparison in Coaxial Tube in Tube Heat Exchanger Operating with Refrigerants R407C and R22
Bibliographic record
Abstract
Due to hazardous environmental impact of the CFC and HCFC refrigerants that are currently used in R&AC systems, in accordance with the Montreal Protocol, actual is exchange of those by new, ecologically acceptable, HFC refrigerants. Therefore system performance analysis was made where the single component R22 refrigerant was replaced by zeotropic mixture R407C. In the system operating at the same conditions, a comparison of heat transfer in coaxial exchanger for R22 and R407C is performed. Experimental data are presented in the form of average heat transfer coefficients as a function of heat flux and mass velocity. Results have showed that in the heat exchange process with R407C refrigerant heat transfer coefficient is lower (10-35%) than for R22. As R407C is a blend of three pure refrigerants (R32, R125 and R134a) with temperature glide of 5-7°C, the concentration shift occurs during two-phase flow in the condenser and evaporator.
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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 | 0.000 | 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) | 0.000 | 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".