Abstract: To provide a refrigerating unit using ammonia as a refrigerant, which uses a lubricant that is excellent in the compatibility with an ammonia refrigerant as well as in the lubricity and the stability.

Abstract: A latent heat storage apparatus is provided and a latent heat storage solution therefor stores and retrieves a cool heat substantially in or from a latent heat thereof necessary for air conditioning, cooling, refrigerating, and so forth. The latent heat storage apparatus has an aqueous solution of a plurality of inorganic salts as a latent heat storage solution in a heat storage tank, formed to retrieve a cold heat from a stored latent heat, the latent heat storage apparatus. The latent heat storage solution is formed of (N-1) kinds of inorganic salts in at least an N-component aqueous solution where N.gtoreq.3. The latent heat storage solution stores the cold heat as the latent heat thereof. The cold heat is retrievable from the stored latent heat at a desired temperature almost invariably within a range higher than the N-component eutectic point and lower than any one of binary eutectic points of salts with water.