Carbon Dioxide Medium Temperature Refrigeration System With Thermal Storage
Bibliographic record
Abstract
Application of Carbon Dioxide as a natural, non-toxic, non-flammable refrigerant in refrigeration systems is steadily gaining interest, especially in locations with moderate climate, like Europe or Canada. However, it is a well-known fact that at higher ambient conditions, when CO2 system operates in transcritical mode, system efficiency is substantially reduced. Currently, there is a large variety of different techniques aimed at the CO2 refrigeration system efficiency enhancement at transcritical operation, like vapor injection, ejectors, expanders, multi-stage compression with intercooling (and combinations thereof) to name a few. On the other hand, thermal storage devices are gaining popularity in many applications including supermarkets, As an alternative approach to other CO2 system enhancement, a novel MT refrigeration CO2 system with a closed couples thermal storage battery is introduced and evaluated. Thermal storage system has a phase change temperature higher than the evaporator temperature and facilitates heat exchange between CO2 and Phase change material. Its operation is simple to be controlled and has, within limitations, very high roundtrip efficiency. The current paper provides the description of this system, explains its modes of operation, reviews experimental investigation of the system with a scaled down thermal storage device. Performance of this system is evaluated using analysis model at different modes of operation. Scaled for a typical 4TON MT REF system, its monthly energy and energy cost consumption is evaluated and compared with a similar sized ejector-enhanced CO2 system, having typical weather and load profile, while applying different energy cost models. Performance of this system is evaluated using analysis model at different modes of operation. Scaled for a typical 4TON MT REF system, its monthly energy and energy cost consumption is evaluated and compared with a similar sized ejector-enhanced CO2 system, having typical weather and load profile, while applying different energy cost models.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.005 | 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".