To obtain the subject material, containing an eutetic mixture of calcium chloride, urea and water as main components, having a capability of endothermically storing and of storage of cryogenic energy at low temperature, and prevented from phase separation and supercooling useful for utilization of low-cost energy in a variety of air conditionings.

This material contains an eutetic mixture of (A) calcium chloride, urea and water [CaCl2.H2O.CO(NH2)2] as a main component and is preferable to include (B) sepiolite [Mg(Si12O30)(OH)4.8H2O] and an alkali metal or alkaline earth metal fluoride or a mixture of borax and graphite as an additive. A mixing ratio of the components is preferable to contain about 45-60wt.% of calcium chloride of the component A, about 15-20wt.% of urea, about 20-50wt.% of water and about 5-15wt.% of the component B. Moreover, in order to form the component B, it is preferable to add about 30wt.% of graphite to a mixture of about 50wt.% of sepiolite and about 20wt.% of the fluoride or borax.