Lets imagine that it instead of the electrons storing the heat energy of an atom the energy is stored in the time space continuum between the orbitals much like the electrons  in a capacitor are stored on the dielectric plates of a capacitor, (not on the conductor as many people assume.) As more energy is absorbed into the time space continuum the space expands pushing the orbits out and increasing their diameter. As the Valance band gets larger in diameter it increases the number of electrons it can support . So as liquid water gains more heat the pressure bands between the orbitals expand pushing the valance band outward, increasing it's circumference and allowing it to be able to support eight electrons instead of seven and a half or seven and sharing the eighth. As we travel toward the center of the atom the orbitals become more stable the closer we get to the nucleus. This is because the outer pressure zones squeeze the inner zones so the further we go toward the center the more pressure there is being exerted from the outer zones. This makes the inner orbits very stable and makes it very hard for electrons to jump between orbits. These pressure bands are affected by heat energy which they absorb creating more pressure and forcing the electrons to move further from the nucleus. If we picture an atom the size of a football stadium, with the electrons orbiting around the upper deck, the nucleus at midfield would be about the size of a quarter. So you see there is plenty of storage space for energy between the infield and the upper decks. We know that energy is stored by atoms some place. The electron is too small to store enough energy and for that matter so is the nucleus. So where else could it be stored? There is only one logical explanation. It is stored in the massive area between the orbitals.