The R744 multi-ejector hybrid CFD and experimentally-based reduced-order model.

The proposed hybrid reduced-order model (HROM) of the four R744 fixed ejectors installed in the multi-ejector module is presented. The ejectors HROM was built by use of the proper orthogonal decomposition together with the radial basis function interpolation to obtain high-accuracy model for a wide range of the subcritical and transcritical operating regimes. The input data for the proposed model was the combination of the experimental data of the investigated ejectors together with the numerical results obtained by use of the ejectorPL platform. The proposed HROM of each R744 vapour fixed ejector obtained a satisfactory accuracy of the motive and the suction nozzle mass flow rates for most validated points and significantly reduced the computational time. Hence, the proposed HROM of the R744 vapour fixed ejectors was successfully implemented to the Modelica dynamic simulations of the R744 refrigeration system to evaluate the system energy performance corresponding to the real ejector performance at different operating conditions.

[1]  Armin Hafner,et al.  Development and performance mapping of a multi-ejector expansion work recovery pack for R744 vapour compression units. , 2015 .

[2]  Marco Corradi,et al.  Energy performance of supermarket refrigeration and air conditioning integrated systems , 2010 .

[3]  Armin Hafner,et al.  Application range of the HEM approach for CO2 expansion inside two-phase ejectors for supermarket refrigeration systems , 2015 .

[4]  Onu Environnement,et al.  Handbook for the Montreal Protocol on Substances that Deplete the Ozone Layer. , 2009 .

[5]  A. Nowak,et al.  System model derivation of the CO2 two-phase ejector based on the CFD-based reduced-order model , 2018 .

[6]  A. J. Kassab,et al.  Solving inverse heat conduction problems using trained POD-RBF network inverse method , 2008 .

[7]  Fabio Inzoli,et al.  Ejector refrigeration: A comprehensive review , 2016 .

[8]  Armin Hafner,et al.  Numerical investigation of an R744 liquid ejector for supermarket refrigeration systems , 2016 .

[9]  Armin Hafner,et al.  Modified homogeneous relaxation model for the r744 trans-critical flow in a two-phase ejector , 2018 .

[10]  Brian A. Fricke,et al.  Comparative analysis of various CO2 configurations in supermarket refrigeration systems , 2014 .

[11]  Alain J. Kassab,et al.  Estimation of constant thermal conductivity by use of Proper Orthogonal Decomposition , 2005 .

[12]  Alan A. Kornhauser,et al.  The Use of an Ejector as a Refrigerant Expander , 1990 .

[13]  Armin Hafner,et al.  Full-scale multi-ejector module for a carbon dioxide supermarket refrigeration system: Numerical study of performance evaluation , 2017 .

[14]  Armin Hafner,et al.  Multi-ejector R744 booster refrigerating plant and air conditioning system integration – A theoretical evaluation of energy benefits for supermarket applications , 2017 .

[15]  Predrag Stojan Hrnjak,et al.  Flash gas bypass for improving the performance of transcritical R744 systems that use microchannel evaporators , 2004 .

[16]  Jostein Pettersen,et al.  Fundamental process and system design issues in CO2 vapor compression systems , 2004 .

[17]  Sven Försterling,et al.  Multi-ejector concept for R-744 supermarket refrigeration , 2014 .

[18]  Armin Hafner,et al.  A computational model of a transcritical R744 ejector based on a homogeneous real fluid approach , 2013 .

[19]  Waclaw Kus,et al.  CFD-based shape optimisation of a CO2 two-phase ejector mixing section , 2016 .