摘要:
A heat-storage agent which can store a large quantity of cold heat in the temperature range of 3-5° C., is highly effective in preventing supercooling, and can retain the supercooling-preventing effect even when hydrate solidification/melting is frequently repeated. Also provided are an aqueous solution which enables the formation of a clathrate hydrate serving as a major component of the heat-storage agent, and a process for producing the clathrate hydrate. The aqueous solution contains at least one of tetra-n-butylammonium bromide and tri-n-butyl-n-pentylammonium bromide as a solute and contains tetraisopentylammonium bromide as a supercooling inhibitor, the weight proportion of the tetraisopentylammonium bromide to the tetra-n-butylammonium bromide and/or tri-n-butyl-n-pentylammonium bromide being in a given range. This aqueous solution is cooled to or below a hydrate formation temperature to thereby produce a clathrate hydrate. The heat-storage agent contains this clathrate hydrate as a major component.