The counter-flow discretized heat exchanger uses a number of conduction elements (which is set by the parameter nCells) as discrete control volumes to exchange heat between two fluid streams. This model differs from DiscretizedCounterFlowHEX by introducing flow-resistances after each control volume, but otherwise is the same, therefore consider the documentation of DiscretizedCounterFlowHEX.
The flowResistances are parametrized by the parameters in the group laminar-turbulent flowRes.