Performance and safety analysis of charge reduced brine to water heat pumps using R290
Bibliographic record
Abstract
The European implementation of the Montreal protocol, the F-gas regulation, restricts the use of refrigerants with high Global Warming Potential (GWP). Thus, low-GWP refrigerants, in particular propane (R290), are be-coming the standard in the strongly growing heat pump market. Current production capabilities and safety solu-tions need to evolve to support the predicted growth. Within this contribution the results of the research project LC150 ("Low Charge 150g") are shown. The focus is on the reduction of charge needed in heat pumps, favorably below 150g Propane, and therefore reducing safety hazards. As part of this project at Fraunhofer ISE many different components were combined and experimentally evalu-ated regarding charge efficiency and thermal performance. Conclusions and correlations will be described based on ErP standards, total charge, COP, heating capacity and more. To support this analysis individual components in refrigerant circuits were replaced. Thus, a quantification of charge impact of a single component within one refrigerant circuit is possible. All measurements are done with compact plate-to-plate refrigerant circuits. The heating capacity range is be-tween 2 kW and 12 kW. The current best solution achieves a specific heating capacity <10 g/kW (g charge/ kW heating capacity) with a SCOP (ErP) >4.3. Additionally an easy-to-apply concept of the heat pump module will be presented, taking manufacturing and safety aspects into account. In this contribution part of the results will be shown and discussed regarding charge efficiency and thermal efficiency of individual components, as well as the safety concepts supporting the charge reduced circuits.
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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 | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".