Publicerad: 2019-02-26
ISBN: 978-91-7685-148-7
ISSN: 1650-3686 (tryckt), 1650-3740 (online)
Models of closure relations, or the expressions that relate the heat transfer coefficients and frictional pressure losses to other variables of the vapor-compression cycle, can have a significant impact on the performance on the overall cycle behavior. We explore three different approaches that may be used in formulating these closure models, and show that approaches that impose a nonlinear algebraic coupling can impose significant computational challenges. In comparison, models that incorporate lowpass dynamics can effectively decouple this nonlinear behavior, resulting in simulations that are faster and demonstrate more realistic and robust behavior.
ASHRAE. HVAC Systems and Equipment Handbook. ASHRAE, Atlanta, GA, 2008.
J.J. Brasz and K. Koenig. Numerical methods for the transient behavior of two-phase flow heat transfer in evaporators and condensers. Numerical Properties and Methodologies in Heat Transfer, pages 461–476, 1983.
Dassault Systemes, AB. Dymola 2018 FD01, 2018.
F.W. Dittus and L.M.K. Boelter. Heat transfer in automobile radiators of the tubular type. University of California Publications in Engineering, 2(13):443–461, 1930.
M.K. Dobson and J.C. Chato. Condensation in smooth horizaontal tubes. Journal of Heat Transfer, 120:193–213, Feb 1998.
H. Elmqvist, H. Tummescheit, and M. Otter. Object-oriented modeling of thermo-fluid systems. In 3rd International Modelica Conference. Linkoping, Sweden, 2003.
K.E. Gungor and R.H.S. Winterton. Simplified general correlation for saturated flow boiling and comparisons of correlations with data. Chem. Eng. Res. Des., 65:148–156, 1987.
J.M. Jensen. Dynamic modeling of thermo-fluid systems with focus on evaporators for refrigeration. PhD thesis, Technical University of Denmark, Department of Mechanical Engineering, 2003.
D.S. Jung and R. Radermacher. Prediction of pressure drop during horizontal annular flow boiling of pure and mixed refrigerants. International Journal of Heat and Mass Transfer, 32 (12):2435–2446, 1989.
C. Laughman, H. Qiao, and D. Nikovski. Kernel regression for the approximation of heat transfer coefficients. In Gustav Lorentzen Natural Working Fluids Conference, 2016.
C. Laughman, H. Qiao, S.A. Bortoff, and D.J. Burns. Simulation and optimization of integrated air-conditioning and ventilation systems. In Proceedings of the 15th IBPSA Conference, pages 1824–1833, 2017.
S. Levy. Two-phase flow in complex systems. New York: John Wiley & Sons, 1999.
P. Li, H. Qiao, Y. Li, J.E. Seem, J. Winkler, and X. Li. Recent advances in dynamic modeling of HVAC equipment. Part 1: Equipment modeling. HVAC&R Research, 20(1):136–149, 2014.
R.W. Lockhart and R.C. Martinelli. Proposed correlation of data for isothermal two-phase, two-component flow in pipes. Chemical Engineering Progress Symposium Series, 45:39–48, 1949.
Modelica Association. Modelica specification, Version 3.4, 2017. URL www.modelica.org.
Modelon AB. Vapor Cycle Library User Guide, 2018. v2.1. H. Qiao and C. Laughman. Comparison of approximate momentum equations in dynamic models of vapor compression systems. In Proceedings of the 16th International Heat Transfer Conference, 2018.
H. Qiao, V. Aute, and R. Radermacher. Transient modeling of a flash tank vapor injection heat pump system - part I: Model development. Int. J. Refrigeration, 49:169–182, 2015.
C.C. Richter. Proposal of new object-oriented equation-based model libraries for thermodynamic systems. PhD thesis, Technische Universität Braunschweig, Institut für Thermodynamik, 2008.
Peter Stephan, editor. VDI Heat Atlas. Springer-Verlag, 2010.
