PERFORMANCE OF INTEGRATED R744-PACKS PART 1 - COMPRESSOR MASS FLOW ESTIMATION BASED ON DATA-DRIVEN MODELS USING ANALYTICAL METHODS AND ACTUAL FIELD MEASUREMENTS

摘要

Rising concerns for climate change impacts along with the new legislation aimed at lowering emissionsindicates the inevitable transition in the cooling/heating industry towards a more energy-efficient solutionwith minimal environmental impact. Integrated refrigeration, air condition and heat recovery solutions byCO2(R744) packs are efficient solutions to high energy demanding building (supermarkets and hotels).Proven performance enhancement of Multi Ejector SolutionTM makes the R744 systems more energyefficient, especially in warm climates, compared to the most conventional synthetic refrigerant systems infood retail applications.Pilot installation in the frame of MultiPACK, an EU funded project (Horizon 2020), provided a wide rangeof data, offering the possibility of evaluating the 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 ofthe data indicated performance improvement of a system with ejector, on average a 35% lower energyconsumption compared to baseline parallel compression R744 system without ejectors.Availability of mass flow measurement, 5 Coriolis mass flow meters on this pilot, enabled the possibility ofcomparison of mass flow rate estimation based on data acquisition from compressors with actualmeasurement. Methods utilized include: Energy balance, volumetric displacement, manufacturerpolynomials, and data-driven method. The comparison reveals the importance of compressor suction anddischarge parameters for obtaining reliable results based on energy balance, volumetric displacement,manufacturer polynomials methods. The current study shows data-driven method performs well afterenough training time with error bounded to 3% and 10 % on low and medium temperature levelcompressors, respectively.