A device (FIGS. 1b, 8c, 14b) for storing and dispensing a fluid and fluid energy using continuous analog modification of the total surface area of one or more solid surfaces against which, on one side of such surface(s), the fluid to be stored and dispensed may proximally and forcibly act and against which, on the opposed side of such surface(s), one or more elastic elements may act, withal producing the effect of a substantially constant static pressure across a range of deformation of the elastic element(s), i.e., a piezoequilibrative effect.