Screening of surface active agents to enhance absorption in ammonia-water systems

摘要

Surface active agents have the potential to substantially enhance heat and mass transfer inammonia-water absorption by reducing the surface tension of the working fluid. The enhancementis caused by improved interactions at the vapor-liquid interface that result from surface tensiongradients. A screening analysis is performed based on the value of surface tension and criticalconcentration. Surface tension measurements are made by a goniometer with and without surfaceactive agents using the pendant drop method. Different concentrations of ammonia and additivesthat span the range of conditions encountered in the operation of an absorption heat pump areconsidered. Based on these assessments, surface active agents and their ideal concentrations forthe enhancement of ammonia-water absorption are recommended.