Experimental research on the crystallization process of the gas hydrate HCFC141b is performed for this paper. The influences of different proportions of calcium hypochlorite or benzenesulfonic acid sodium salt on the crystallization process are studied. The results show that the degree of subcooling of formation is obviously decreased, and the formation rate of the gas hydrate is greatly accelerated by adding reasonable proportions of the additives. The degree of subcooling of formation decreases 0.78 degrees C by adding benzenesulfonic acid sodium salt of 0.03%, and the formation rate of the gas hydrate increases 0.2 g/s by adding calcium hypochlorite of 0.08%. In the cool storage system, clathrate hydrates can be formed effectively, and thermal energy can be stored efficiently. When adding benzenesulfonic acid sodium salt of 0.03%, the cold energy stored is 4.74 MJ, and the cool storage density is 206.07 MJ/m(3). The performance of this cool storage system can meet the needs of practical air conditioning engineering. (c) 2006 Elsevier Ltd. All rights reserved.