Performance of a Residential-Sized GAX Absorption Chiller

This research effort involved experimentally testing an advanced-cycle, ammonia-water absorption chiller with a cooling capacity of 17.6 kW (5 refrigeration tons (RT)). The system was a generator-absorber heat exchange (GAX) cycle and was sized for residential and light commercial use, where very little absorption equipment is currently used. The components of the cycle were assembled with instrumentation, including flow meters, pressure transducers, and thermocouples. The findings of the research were cycle cooling load and coefficient of performance (COP), as well as many component heat duties and working fluid state points throughout the cycle. The COP of the chiller at essentially full load was measured at 0.68. A simulation of the GAX cycle was performed with a computer program that predicted the heat duties of each component and the cooling load of the cycle. The simulation of the GAX cycle and experimental testing compared closely. Existing market research shows that significant business opportunities exist for a GAX heat pump or chiller with a cooling COP of 0.70 or greater. The work performed in this study consisted of testing a GAX cycle with a COP that approached the target value of 0.70 and identified improvements that must be made to reach the target COP value.