TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The base heat transfer fluid has kinematic viscosity of not more than 14 cSt at -40 degreesC, boiling point of at least 80 degreesC and a flash point of at least 59 degreesC by Pensky-Martens method.The ratio of nanometer sized phase change material/base heat transfer fluid is 0.1-30 (preferably 25) volume %.The sized phase change material comprises particles of the phase change material having a diameter of 10-100 Angstrom (preferably 50-100 Angstrom). The capsules have diameters of 10-1000 Angstrom (preferably 50-100 Angstrom).The outer shell of the capsules is made of a material comprising alkylated polysiloxane, or crosslinked hybrid metal-organic precursors having an oxoalkoxide ligand and substituted hydrocarbon ligand.The phase change material includes trimethylolethane, acetamide, monoaminopentaerythritol, 2-hydromethyl-2-methyl-1,3-propanediol, arachidic acid, or behenic acid.The oxoalkoxide ligand includes methoxy, ethoxy, propoxy, isopropoxy and butoxy.The substituted hydrocarbon ligand includes 1-4C radicals and phenyl.Preferred Method: The capsules are made by preparing a micelle or a reverse micelle containing the phase change material and crystallizing the phase change material inside and micelle or the reverse micelle.The phase change material is encapsulated within the capsules which is then stabilized.The reverse micelle is prepared by dissolving the phase change material in water, mixing the dissolved phase change material with a surfactant and dispersing a mixture of the dissolved phase change material with the surfactant in an organic solvent.The micelle is prepared by dissolving the phase change material in an non-polar solvent and dispersing the dissolved phase change material in water.The capsules are stabilized by applying a coating of block copolymer to the capsules.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The metal includes silicon, titanium, aluminum, zirconium, vanadium, niobium and tantalum.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The outer shell can be made of crosslinked amphiphilic block and/or graft co-polymers (preferably hydrophilic and oleophilic blocks (AB) diblock co-polymers. EXAMPLE - None given.