Submission
Performance of integrated R744-packs Part2 - Ejectors performance, a comparison of onsite measurements and model predictions
DOI: 10.18462/iir.compr.2021.0401
Session: Technologies with CO2, ammonia and hydrocarbons
Accept state: Submission accepted
Authors
| Name | Organization | |
|---|---|---|
| Ekaterini Kriezi, PhD | Danfoss A/S | |
| Vahid Khorshidi, MSc. | Danfoss A/S | |
| Christian Schlemminger, Dr.Ing. / PhD | SINTEF Energy Research | |
| Engin Söylemez, PhD | Norwegian University of Science and Technology NTNU | |
| Armin Hafner, Professor | Norwegian University of Science and Technology NTNU |
Abstract
Rising concerns for climate change repercautions along with the new legislations aimed at lowering emissions indicates the inevitable transition in cooling/heating industry towards a more energy efficient solutions with minimal environmental impact. Integrated refrigeration, air condition and heat recovery solutions by CO2(R744) packs are efficient solutions to high energy demanding building (supermarkets and hotels). Proven performance enhancement of Multi Ejector Solution (TM) makes the R744 systems more energy efficient, especially in warm climates, compared to the most conventional synthetic refrigerant systems in food retail application.
Pilot installation in the frame of MultiPack, an EU funded project, provided a wide range of data, offering the possibility of evaluating real performance of each ejector group: high pressure (HP), low pressure (LP) and liquid ejector(LE), by running the system in different operating modes. Analysis on the data indicated performance improvement of a system with ejector, on average a 35% lower energy consumption compared to baseline parallel compression R744 system without ejectors.
Availability of mass flow measurement, enabled the possibility of comparison of mass flow rate estimation based on data acquisition from compressors with actual measurement. A data- driven models were used to estimate the performance of ejectors using onsite data from various operating modes and compared with simulated performance and lab measurements.
Careful data pre-processing allows the data-driven model to predict the ejector performance with acceptable accuracy compared to mass flows and performance data derived from onside measurements in combination with models validated by highly accurate lab experiments.
Keywords
R744 (CO2); Ejectors, Integrated systems, Refrigeration, Data-driven models, Energy saving