Self-Thermal Insulation of Containers by the Precipitation and Formation of a Gas Film at the Walls for Thermal Energy Storage

In this study, consideration is given to a novel idea for thermal storage enhancement by the passive thermal self-insulation of the inside walls of containers when they are deliberately coated by nucleation sites and the working fluid is supersaturated with a certain gas. Here, it is proposed that a gas film blanketing the inside surfaces of the container may be promoted by previously supersaturating the working fluid in which the heat is to be stored (e.g, molten salts, water, etc) and covering the surface with nucleation sites. The last achievements in micro/nano surface modification allow the control in number and roughness of the surface with nucleation sites near to its critical radius for nucleation which translates into a vigorous gas precipitation even working at relatively low supersaturation rates. Utilizing a simplified geometrical and physical model, an expression for the average thickness of the film gas and the heat transfer coefficient was derived.