negligible leakage


in a recuperator mostly cause a short cut between the supply
side of the primary medium and the outlet side of the secondary medium
and/or vice versa. This causes an apparent increase of the effectiveness
as the outlet flow mixes directly with the supply flow. With a complete
short cut the measured effectiveness seems even to be a 100%. If we
define the effectiveness as the ratio of the power transferred to one
medium to the maximum power, the effectiveness decreases due to a
leak, see fig.1.


Figure 1 effectiveness as function of the leak rate

Any Recair recuperator is tested for leakage, resulting in an average
leak <0,5%.

The mostly allowed 5% maximum leak causes a 5% performance