At 10.2 L/min flow rate, the power to be dissipated is a maximum at only 2.6 W. At a typical flow of 5.4 L/min, it is only 0.56 W. The heat transfer section shows that the oscillating motion of the piston, which causes bidirectional fluid flow to occur in the gap 30, creates extremely favorable conditions which allow transfer of this heat right through the gap.