The factors impacting the Achievement of Chilled Water Set Point in an Absorption Cooling Plant: A Six Sigma Approach, UWI Mona Central AC Park, Kingston, Jamaica

The research seeks to conduct an extensive case study into the factors impacting the achievement of chilled water setpoint in an absorption cooling system and, to identify possible ways of improving the attainment of chilled water setpoint. Six Sigma was utilised to support the case study findings. A combination of qualitative and quantitative datawas collected from several on-site visits at the UWI Mona AC park facility. Process capability assessments conductedrevealed that both chillers in the plant were below the minimum Cpk value of one. Chillers one and two had Cpkvalues of -0.12 and 0 respectively indicating that the process is incapable of consistently hitting the target.Temperature verification exercises conducted on the three major system sensors indicated that they were fullyfunctional and within the acceptable margin of error, of 10%. Several regression models were done seeking tohighlight the relationships between cooling water inlet, chilled water outlet, and wet bulb temperatures. A regressionmodel comparing actual plant records and predicted data from the plant conceptual model was done. The regressionfor cooling water inlet temperature and wet bulb temperature deviated from theory, where a very strong relationshipwas expected; however other factors contributed to this. Additionally, the predicted values from the plant modelsimulation produced greater relationships for all three parameters being compared again indicating other factors atwork. Water Quality Parameters of conductivity, hardness and pH fell outside of the minimum threshold standard forboth the Original Equipment Manufacturer (OEM) and industry standards. Total Dissolved Solids (TDS) values werewithin acceptable range. The investigation revealed that important instruments such as tension meter and laseralignment tools were missing from belt maintenance activities. This compromised the validity of maintenanceactivities. Frequent belt failure negatively impacted both chilled water and cooling water temperatures. There was a1.848 ͦ C improvement in cooling water inlet temperatures and 2.559 ͦ C improvement in chilled water outlettemperature post belt maintenance. Six faults accounted for 80% of disruptions in cooling on the plant: power cut,burner fault, chilled water flow switch, freezing, cooling tower belt failure, and cooling water flow switch. There wasnoticeable improvement in Chilled water outlet temperature of 1.24 ͦ C post vacuuming.In keeping with the objective of this research project, it is evident there were several inconsistencies with overall plantoperation and maintenance. The investigated factors have clearly highlighted these issues where there were severaldeviations from best practices and industry standards. This confirms the lack of proper programs to adequately managethese factors. Recommendations have been made to minimize the negative effects of the identified factors, which willimprove the plants ability to consistently achieve chilled water set point (7 ͦ C +/- 1 ͦ C) and improve overall plantperformance