Heat Transfer Considerations for DC Busbars Sizing

Abstract

The main DC busbars connecting the rectifiers to the potrooms or connecting the potrooms of a potline typically consist of several naturally cooled parallel aluminum bars. For economic optimization, busbar sizing is usually based on the minimum aluminum mass at the maximum allowable temperature. An adequate representation of the system’s heat dissipation is therefore required for the efficient and effective design of both the busbars (preventing excessive costs or overheating) and expansion joints.

To accomplish this, detailed Computational Fluid Dynamics (CFD) simulations are used to evaluate the heat losses from a tunnel enclosed group of busbars to the surroundings. In addition, a simplified calculation methodology based on semi-empirical convection correlations and analytical radiation view factors is proposed for the fast evaluation of different design parameters.

The approach is discussed in the context of potential industrial applications, for example increasing the line amperage of existing potlines, to illustrate the methodology’s value.