The effects of the refrigerant contamination on the absorption chiller performance

Abstract

The objective of this work is to investigate the influence of the contamination degree of the refrigerant on the cooling capacity and COP,and to compare three different types of absorption machines; a single-effect, a double-effect parallel-flow, and a double-effect series-flow type absorption chiller A simulation program for the absorption cycle is prepared for the purpose. Using some assumptions, the calculations have been performed with the mass balance equations, energy balance equations, as well as the state equations. The range of the contamination is from 1.00 to 1.17 (in specific gravity unit) in the present study. First of all, while the contamination degree is increased from 1.00 to 1.17, the refrigerant temperature increases from 5.45 degreesC to 5.55 degreesC (single-effect), from 5.60 degreesC to 5.79 degreesC (parallel-flow), and from 5.71 degreesC to 5.91 degreesC (series-flow). As a result, the temperature differences of the refrigerant and the chilled water become lower, and the solution concentration is increased due to the decreased quantities of the refrigerant vapor As the contamination degree of the refrigerant is increased, the cooling capacity of the absorption machine is diminished with the same operating conditions. For the single-effect absorption machine, the cooling capacity where the contamination degree is 1.17 falls down to 87.5% of the original standard condition. For the double-effect machine, the effect of refrigerant contamination on capacity becomes more severe, that is, the capacity is decreased by 80.0% for both the parallel-flow type and the series-flow type machine. Also, COP is reduced to 96.6%(single-stage), 93.9%(parallel), and 91.0%(series).