Patent ID: 8636269

Claim:
A method of effecting heat exchange between counter current airflows in an evaporative heat exchanger, said heat exchanger including a heat exchange core comprising a plurality of alternating wet and dry passages, each passage comprising opposed corrugated surfaces with corrugations of said opposed corrugated surfaces being at intersecting angles, the opposed corrugated surfaces of each wet passage including a water wettable material adapted to retain water and transfer water vapour from the wettable material to air flowing along each respective wet passage; the corrugated surfaces of each dry passage being vapour resistant and cooled as water vapour transfers from the wettable material to air flowing along each adjacent wet passage, and causing a portion of the airflow exiting the dry passages to be returned to the wet passages in counter flow to the airflow in the dry passages, characterised in directing the counter current airflows in the wet and dry passages in a substantially horizontal direction, supplying water from above the core to the wettable material of the wet passages in a descending flow pattern and preventing water from entering and descending the dry passages.