Compressibility of the capacitance system (e.g., vessels, accumulator)
attached to the shell-side (Vc/Bf) dP, where Vc is the
liquid volume in the capacitance system. If there is a vapour
space in this system, Vc would be the sum of the actual liquid
volume plus an equivalent liquid volume Ve to account for the
vapour space of volume Vcg via the following equation [18]: