Estudo experimental e modelo de simulação para avaliação do retrofit do R-22 em unidades de climatização do tipo split
Bibliographic record
Abstract
Since the adoption of the Montreal Protocol in 1987, several amendments have occurred to strengthen (such as Kyoto in 1997) and even expedite goals, encouraging industries to develop refrigeration systems with lower environmental impacts by using refrigerants with low GWP (Global Warming Potential), for example. In parallel to this, there is a large fleet of refrigeration units in developing countries like Brazil, which operate with high GWP fluids like R-22, and discarding such equipment due to the obsolete refrigerant would entail significant losses not only for the owners but also for the environment. With the aim of repurposing these units, this study aimed to evaluate alternative fluids that replace current ones with as few modifications to the system as possible and without significantly compromising the performance of these sets. To achieve this, a mathematical model of a refrigeration system was developed, which was later experimentally validated for R-22. Subsequently, this model was incorporated into a thermal zone based on the environmental conditions of Belo Horizonte from December 2022 to November 2023 (one year), and the fluids R-407C, R-444B, and R-454C were compared to R- 22 through COP (Coefficient of Performance), cooling capacity, and TEWI (Total Equivalent Warming Impact), in addition to the analysis of climatic seasonality. After the analyses, it was possible to observe that R-407C has a COP and cooling capacity 6% and 3% lower than R-22, respectively, with TEWI being 5% lower than the reference. On the other hand, R-454C has a COP and cooling capacity 16% and 11% lower than R-22, respectively, but it has a total TEWI 55% lower than the reference due to its low GWP. Finally, R-444B was identified in this study as the best alternative to replace R-22 at mild temperatures, as it has a COP and cooling capacity 15% and 9% higher, respectively, and also has a TEWI 55% lower than the reference.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.002 | 0.002 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.003 | 0.001 |
| Open science | 0.002 | 0.000 |
| Research integrity | 0.003 | 0.003 |
| 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; both teacher heads agree on what is shown here.
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".