Kinetic energy of the DM as a function of time for both heat conduction set-ups. For heat flowing from the DM to baryons (DM→Gas) the results are given in blue and for heat flowing from baryons to DM (Gas→DM) in green. We display the results for both methods SPH (dotted) and MFM (dashed). The red lines give the exact solution according to Eqs. (19) and (20). The upper panel gives the absolute values, and the lower panel displays the ratios to the exact solution.