Investigations of selection of nanofluid applied to the ammonia absorption refrigeration system

20 types of nanoparticles mixed pairwise orthogonally with 10 types of dispersants are added in ammonia-water, respectively, to observe the dispersion stability of suspension. Ratio of varying absorbency is defined to investigate the dispersion stability of nanofluids compared with the conventional methods of measuring the height of supernatant layer or just measuring the absorbency. The dispersion stabilities of nanoparticles employed are divided into three levels and the influence of boiling on the dispersion is investigated. The results show that the nanoparticles with better dispersive characteristics in dry condition can more easily disperse in ammonia-water directly or be strengthened dispersivity by dispersant. Ratio of varying absorbency is more practical than the height of supernatant layer to investigate the dispersion stabilities of some nanofluids which just fade or aren't stratified clearly after storage, and is more efficient to contrast the dispersion stabilities of different types of nanofluid than absorbency.

► Nanofluids for ammonia absorption refrigeration system are investigated.
► Ratio of varying absorbency is more practical than conventional methods.
► Dispersion stability of nanoparticles employed is divided into three levels.
► The dispersive characteristics of the dry nanoparticles influence dispersion in solution.
► Boil has different effects on dispersions of different types of nanofluids.