Describes a model and solution algorithm developed to predict the dynamic performance of an ice-on-pipe brine thermal storage component. Ice-on-pipe brine systems are unique in that both charging and discharging occur from the brine flowing on the inside of the pipes, thus, multiple layers of ice and liquid could form on the outside of the pipes during a sequence of partial charge and discharge cycles. The analysis is developed by considering the thermal storage unit as a collection of tube pairs in a counterflow arrangement. A typical tube pair is numerically divided into a number of sections in the axial direction and one-dimensional, radial heat transfer is considered in each of these axial sections. The governing equations are thus reduced to a coupled, nonlinear, first-order system in the time variable for the unknown temperatures and ice-liquid phase boundaries in each axial section. These equations are numerically integrated over discrete time steps using a fully implicit scheme to produce a set of nonlinear algebraic equations. An iteration procedure is developed to solve the resulting algebraic equations in which possible configuration changes due to the formation or destruction of ice and liquid layers are considered. The validation of the model is described in a companion paper (Nelson et al. 1996).

KEYWORDS: year 1996, algorithms, calculating, performance, energy storage, brine, ice, heat flow, components, ice storage