Failure analysis of condensing units for refrigerators with refrigerant R134a, R404A

Abstract The article deals with analysis of defects of condensing units for refrigerators with R134a, R404A refrigerant, which caused frequent complaints to the company. Up to 30% of the claims related to a valve of the condensing unit. Various quality management tools and risk assessment methods were used to solve the problem. The Pareto analysis and Lorenz curve were used to determine the significant minor causes that need to be addressed to resolve the majority of problems. Based on the Fault Tree Analysis (FTA), a change in the technological process was made for assembly and installation procedure of the valve to the base plate and in hard brazing of the tube and the valve, thus reducing the number of defects in the condensing unit by 40%. Valve defects have been reduced by nearly 50%.

[1]  D. N. Asimakopoulos,et al.  Parametric prediction of the buried pipes cooling potential for passive cooling applications , 1995 .

[2]  Y. Shabtay,et al.  New brazing processes using anneal-resistant copper and brass alloys , 2004 .

[3]  Simone Baldi,et al.  Real-time monitoring energy efficiency and performance degradation of condensing boilers , 2017 .

[4]  Yung-Chung Chang,et al.  Optimal chiller loading by genetic algorithm for reducing energy consumption , 2005 .

[5]  Michael Wetter,et al.  Robust on-line fault detection diagnosis for HVAC components based on nonlinear state estimation techniques , 2014 .

[6]  Zicheng Yan,et al.  The Application of EASY5 Software to Simulate the Operating Characteristics of Parallel-Flow Condensing Unit , 2011 .

[7]  Eckhard A. Groll,et al.  The Sensitivity of Chiller Performance to Common Faults , 2001 .

[8]  Cristian Cuevas,et al.  New approach for performance testing of air-cooled condensing units , 2003 .

[9]  Abdollah Avara,et al.  Optimum placement of condensing units of split-type air-conditioners by numerical simulation , 2008 .

[10]  Haorong Li,et al.  Fault Detection and Diagnosis Process for Oversizing Design on Multiple Packaged Air-conditioning Units , 2016 .

[11]  Ton van der Wiele,et al.  Managing Quality 6e: An Essential Guide and Resource Gateway , 2016 .

[12]  M. Santamouris,et al.  On the performance of buildings coupled with earth to air heat exchangers , 1995 .

[13]  Qiang Zhou,et al.  A model‐based fault detection and diagnosis strategy for HVAC systems , 2009 .

[14]  I Chaer,et al.  Refrigerant emissions and leakage prevention across Europe - Results from the RealSkillsEurope project , 2012 .

[15]  Y. Iwai,et al.  A study of cavitation bubble collapse pressures and erosion part 1: A method for measurement of collapse pressures , 1989 .

[16]  Z. Huda,et al.  Development of optimum process parameters and a study of the effects of surface roughness on brazing of copper , 2015 .

[17]  Nicolae Antonescu,et al.  Parametrical Functioning Study for a Small Boiler Condensing Unit , 2017 .

[18]  Clifton A. Ericson,et al.  Hazard Analysis Techniques for System Safety , 2005 .

[19]  Jacques Mongis,et al.  Cavitation wear in plain bearing: Case study , 2005 .

[20]  Ronan Grimes,et al.  Design and Testing of a Novel Air-cooled Condenser for Concentrated Solar Power Plants , 2014 .

[21]  Young-Chul Park,et al.  Analysis and optimization of nitrile butadiene rubber sealing mechanism of ball valve , 2009 .

[22]  Qiuwang Wang,et al.  Effect of building re-entrant shape on performance of air-cooled condensing units , 2000 .

[23]  Graeme Maidment,et al.  An investigation of refrigerant leakage in commercial refrigeration , 2017 .

[24]  Hansjürg Leibundgut,et al.  Stuck in a stack—Temperature measurements of the microclimate around split type condensing units in a high rise building in Singapore , 2014 .

[25]  James E. Braun,et al.  Evaluating the performance of fault detection and diagnostics protocols applied to air-cooled unitary air-conditioning equipment , 2013 .

[26]  Zhang Lin,et al.  Placement of condensing units of split-type air-conditioners at low-rise residences , 2002 .

[27]  B. Poulson.  Complexities in predicting erosion corrosion , 1999 .

[28]  Andrew W. Batchelor,et al.  11 – Abrasive, Erosive and Cavitation Wear , 2006 .

[29]  Joseph Khedari,et al.  Field study using the ground as a heat sink for the condensing unit of an air conditioner in Thailand , 2001 .

[30]  Yung-Chung Chang,et al.  Application of genetic algorithm to the optimal‐chilled water supply temperature calculation of air‐conditioning systems for saving energy , 2007 .