Use of aqueous microcapsule dispersions as heat transfer liquids

Use of aqueous microcapsule dispersions with latent heat storage materials as capsule core and a polymer as shell, which are obtainable by heating an oil-in-water emulsion in which the monomers, free radical initiators and the latent heat storage materials are present as a disperse phase, where the monomer mixture comprises 30 to 100% by weight, based on the total weight of the monomers, of one or more monomers I chosen from C1-C24-alkyl esters of acrylic acid and methacrylic acid, methacrylic acid and methacrylonitrile, 0 to 80% by weight, based on the total weight of the monomers, of a bi- or polyfunctional monomer II which is insoluble or sparingly soluble in water and 0 to 40% by weight, based on the total weight of the monomers, of other monomers III, as heat transfer liquids.