PURPOSE: To enhance heat exchange efficiency by disposing the strips of polymer laminated grids constituted by connection so as to intersect with two directions with respect to peripheral edge strips and offsetting these strips from the strips of the upper and lower grids.

CONSTITUTION: The strips of the polymer laminated grids 16 are disposed to intersect with the two directions with respect to the peripheral edge strips and are made offsettable from the strips of the grids 19 disposed above and below the same. The central apertures 20 of the connecting bars 6 are disposed to deviate from connecting pieces 13. The connecting bars 6 are made continuously rotatable within a range of 180° above the respectively succeeding layers and the grids 19 are made rotatable 180° on the respective second layers. Consequently, the cooling stack which is suitable for use for liquid contg. coarse contaminants and oil in transverse facing and alternating gaseous streams and has a high exchange rate is obtd.