Fast Calculation of Refrigerant Properties in Vapor Compression Cycles Using Spline-Based Table Look-Up Method (SBTL)

Lixiang Li
Modelon Inc, USA

Jesse Gohl
Modelon Inc, USA

John Batteh
Modelon Inc, USA

Christopher Greiner
Ford Motor Company, USA

Kai Wang
Ford Motor Company, USA

Ladda ner artikelhttp://dx.doi.org/10.3384/ecp1815477

Ingår i: Proceedings of The American Modelica Conference 2018, October 9-10, Somberg Conference Center, Cambridge MA, USA

Linköping Electronic Conference Proceedings 154:8, s. 77-84

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Publicerad: 2019-02-26

ISBN: 978-91-7685-148-7

ISSN: 1650-3686 (tryckt), 1650-3740 (online)


Refrigerant property calculation has a significant impact on the computational performance of vapor compression cycle simulations. This paper summarizes a Modelica implementation of Spline-Based Table Look-Up Method (SBTL) for fast calculation of refrigerant properties. External C functions are used for faster spline evaluation and inversion. Significant improvement in computation speed was observed without sacrificing accuracy. An SBTL property model of R134a is first validated against a highly accurate Helmholtz energy equation of state (EOS) model. Then the new model was tested rigorously from single function calls, to heat exchanger test bench, to system models of the vapor compression cycle in Modelon’s Air Conditioning Library. Finally, an SBTL property model of R1234yf was used in a drive cycle simulation and a shutdown-startup test of two complex air conditioning system models developed at the Ford Motor Company. These system models are running more than twice the speed of the ones using Helmholtz energy EOS.


Refrigerant Properties, Equation of State (EOS), Thermodynamic Modeling, Vapor Compression Cycle, Air Conditioning, Spline Interpolation, Computational Performance


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