EXPERIMENTAL STUDY ON AN AUTOMOBILE AIR CONDITIONING SYSTEM WITH INTERNAL HEAT EXCHANGER USING THE REFRIGERANTS HFC134a AND HFO1234yf
Bibliographic record
Abstract
Despite being favorable to stratospheric ozone, hydrofluorocarbons (HFCs), a synthetic replacement to chlorofluorocarbons (CFCs), have a high global warming potential (GWP). Despite this, HFCs are still used in many applications, including air conditioning and refrigeration. The HFCs were included in the category of greenhouse gases under the Kyoto Protocol, which was negotiated in 1997 and entered into force in 2005, and it was mandated that the emissions of these gases be monitored and controlled. In order to meet the requirement of an 85% reduction in HFCs, a phase-out of HFCs was suggested by the 2015 EU regulation and the 2016 Kigali Amendment to the Montreal Protocol. This process will last until 2036 in industrialized countries and until 2047 in nonindustrial countries. The global warming potential of the HFC134a refrigerant used in automobile air conditioning is 1300, which prompted researchers to look for new low-GWP refrigerants. The hydrofluoroolefin (HFO) refrigerant HFO1234yf, with a GWP of 4 or less, shows potential for use in the automobile air conditioning (AAC) area, according to recent research. Due to frequent HFC leaks due to pipe failures brought on by vibration, the AAC needs special attention. In this research, attention is given to the low-GWP refrigerant R1234yf to explore AAC system performance, and comparisons are made with the currently used refrigerant HFC134a. The experiments are performed by including and excluding the internal heat exchanger (IHX) (liquid-to-suction heat exchanger) in the circuit. Without any design modifications R1234yf (with suitable lubricating oil) can be charged into an existing R134a AAC system, the R1234yf refrigerant charge being 9-10% less than that of R134a. The results show that the use of IHX is advantageous for R1234yf. Even though R134a performed better, R1234yf with IHX is a better alternative to an AAC system working with R134a without IHX, with only a slight compromise in the performance of the system.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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".