TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Method: The silica-coated metal particle (S1) is oxidized at first location, moved to second location, and reduced at the second location, thus accumulating heat from second location. The silica-coated metal particle is reduced at first location, moved to second location, and oxidized at the second location thus providing heat at second location. In method (M1), the oxidizing step involves contacting silica-coated metal particle with oxygen, and reducing step involves contacting silica-coated metal particle with hydrogen gas or reduction reagent, and providing electrode to apply negative potential of 0.5-20 volts to silica-coated metal particle. The method (M1) is performed inside power source of vehicle and is repeated on same silica-coated metal particle, where diameter of particle remains substantially constant after repeated use. In method (M2), the baking occurs at 500-800 degrees C, and the stream of gas comprises hydrocarbon, thus endowing silica layer with electrical conductivity, and majority of gas comprises 1C, 2C and/or 3C hydrocarbon molecules. Preferred Device: The second chamber is operationally connected to provide heat to device that requires heat. The first chamber is configured to cool a device that generates heat.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Particle: The silica-coated metal particle (S1) comprises 0.1-2% of coating having pores of diameter of 0.05-5 nm. The diameter of silica-coated metal particle is 1-100 nm. The volume fraction of coating to particle is not greater than 1%. The surface of metal core is in oxidized or reduced state. EXAMPLE - The particle with outer diameter of 110 nm included a core with diameter of 100 nm that contained 90 wt.% magnesium. The core was coated by layer of amorphous silica with uniform thickness of 5 nm. 1% of surface area of coating included pores that passed through silica coating to metal core. The pores had average diameter of 0.3 nm. The pores permitted molecular oxygen to contact metal core. The silica coated metal particle was thus obtained, which was electrically conductive.