Analysis of refrigerant pipe pressure drop of a CO₂ air conditioning unit for vehicles

This study investigates the pressure drop in refrigerant pipes of a CO₂ automotive air conditioning unit. A test rig to measure the pressure drop of arbitrarily shaped pipes is presented. As boundary conditions at the inlet of the test section, mass flow, pressure and enthalpy of the refrigerant are independently adjustable to values that cover the whole operating range of a CO₂ automotive air conditioning system for cars in the premium segment. Numerical analysis using CFD and a one-dimensional modelling tool is carried out. The pressure drop for the suction pipe reaches values of up to 500 mbar. CFD simulation predicts the pressure drop with an error of 25.7% for single-phase flow whereas the deviation using one-dimensional models is 46.5%. During two-phase flow the error increases to 55.8% with one-dimensional models and 42.4% using CFD.

Subjects

Air conditioning

Piping

Pressure drop

R744

DDC Class

600: Technik

Funding(s)

Modellierung und Optimierung von CO₂-Kühlkreisläufen

More Funding Information

The authors would like to thank TuTech Innovation GmbH, Hamburg, Germany, for their financial support for this research project.

Lizenz

https://creativecommons.org/licenses/by-nc-nd/4.0/

Name

1-s2.0-S0140700719301616-main.pdf

Size

1.62 MB

Format

Adobe PDF

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Analysis of refrigerant pipe pressure drop of a CO₂ air conditioning unit for vehicles