Refrigerant charge reduction in small commercial refrigeration systems

Jiang, Lingyan

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https://hdl.handle.net/2142/72846 Copy

Description

Title

Refrigerant charge reduction in small commercial refrigeration systems

Author(s)

Jiang, Lingyan

Issue Date

2015-01-21

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

Hrnjak, Predrag

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)

• charge minimization
• refrigeration system
• flattened tube

Abstract

This paper presents analysis of location of refrigerant inventory and numerical results of charge reduction in a typical bottle cooler. The original unit was first characterized by determining its capacity, the coefficient of performance (COP), pull-down characteristics, and total charge using non-intrusive instrumentation. Then the unit was instrumented by insertion of valves to separate main components and allow measurement of the charge in each of them, as well as pressure transducers, a mass flow meter, and thermocouples. Charge optimization and charge distribution experiments were conducted. The condenser is found to be the component that retains the most charge. The system was modeled using Engineering Equation Solver (EES) for calculation of performance and charge. Models were fully validated by experimental results at steady state. Different void fraction correlations were analyzed and utilized to predict charge distributions in heat exchangers. Discussion of the results and recommendation for charge reduction is provided. With the aim of reducing charge without penalizing system performance significantly, the tubes of the round-tube finless condenser were flattened. Charge optimization and charge distribution experiments were again conducted for the system with a flattened-tube condenser. Experimental results show good match with the model prediction.

Graduation Semester

2014-12

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http://hdl.handle.net/2142/72846

Copyright and License Information

Copyright 2014 Lingyan Jiang

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