Performance Investigation of R290 As A Substitute to R22 Refrigeration System
Bibliographic record
Abstract
In this study, Use of natural refrigerant R290 can play a vital role in fulfilling the objectives of the international protocols like Montreal and Kyoto. Because of environmental issues such as ozone depletion and global warming, R22 needs to be phased out on urgent basis. This paper analyzes the possibilities of R290 as a potential substitute to R22. Thermodynamic performance analysis of refrigerants R290 and R22 was carried out using standard vapour compression cycle, with evaporating temperature range of -5oC, condensing temperature of 30°C and compressor efficiency is taken as 65%, based on analytical calculations. Performance parameters like, coefficient of performance, refrigeration effect, and compressor work. All the analysis in this paper for performance comparison of refrigerant is done by engineering equation solver software commonly known as EES software. From the analysis it is found to be that R290 is a better substitute of R22. However, the flammable characteristics of R290 prevented its wide application in the large air conditioning system. Thus special precautions are needed for its use and maximum charge quantity of R290 in refrigeration system is also restricted by international safety standards. Recently the study of flammable refrigerants used in air conditioner has attracted worldwide attention. Coefficient of performance with R290 is slightly lower than that of with R22. However, by adding a liquid-vapour heat exchanger in the vapour compression cycle we can increase coefficient of performance and other properties. Engineering Equation Solver (EES) was used to simulate a mechanical refrigeration system in two configurations: modified system with liquid-vapour heat exchanger and system without liquid-vapour heat exchanger. The results revealed that the liquid-vapour heat exchanger has a significant effect on the system performance as it influences the sub cooling and superheating temperatures. The results showed us that the high value of the coefficient of performance (COP) was achieved by the modified system which has a single stage vapour compression refrigeration system with refrigerant R290. Overall, R290 can be a better substitute to R22 in real applications because of its excellent environmental properties and thermo physical properties. R290 is a low cost, widely available and efficient. They also have zero ozone depletion potential and very low global warming potential. Despite the flammability, they are increasingly used in domestic refrigerators. In 2010, about one-third of all household refrigerators and freezers manufactured globally used isobutane or an isobutane/propane blend, and this was expected to increase to 75% by 2022.
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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".