Distribution of refrigerant and lubricant in automotive air conditioning systems

Jin, Shenghan

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https://hdl.handle.net/2142/34290 Copy

Description

Title

Distribution of refrigerant and lubricant in automotive air conditioning systems

Author(s)

Jin, Shenghan

Issue Date

2012-09-18T21:09:46Z

Director of Research (if dissertation) or Advisor (if thesis)

Hrnjak, Predrag S.

Department of Study

Mechanical Sci & Engineering

Discipline

Mechanical Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• automotive air conditioning
• refrigerant retention
• lubricant retention

Abstract

In automotive air conditioning (A/C) systems, the compressor lubricant is circulated throughout the system with refrigerant. At different oil concentrations, the circulating mixture exhibits different properties, which affects the characteristics of heat transfer, pressure drop and mass retention in each component. The purpose of this thesis is to measure and model refrigerant and lubricant mass distribution in each component of an automotive A/C system. Quick Closing Valve Technique (QCVT) combined with Remove and Weigh Technique is employed to measure the refrigerant mass, with an overall uncertainty within 2%. Three different techniques-Remove and Weigh, Mix and Sample and Flushing- are used to determine the mass of lubricant. The total mass of lubricant in the system is determined with 5% uncertainty in average. R134a and its new environmental friendly alternative R1234yf are used with PAG 46 oil as working fluid at different Oil Circulation Ratio (OCR), ranging from 2% to 4%. Experiments are conducted in two system, one with a fixed Orifice Tube (OT) and low pressure side accumulator, the other with a Thermal Expansion Valve (TXV) and a high pressure side receiver. In each system, R134a and R1234yf show similar results in terms of refrigerant and lubricant retention at I-35 steady state condition. An experimentally validated model is developed to estimate both refrigerant and oil retention in the microchannel condenser and plate-and-fin evaporator that are used in the experimental system.

Graduation Semester

2012-08

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http://hdl.handle.net/2142/34290

Copyright and License Information

Copyright 2012 Shenghan Jin

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