The invention relates to a heat exchanger with a tube register through which a fluid to be cooled or heated is conveyed. The tube register is sprayed, in the same direction as the fluid, with water, and air flows therethrough in the opposite direction to the fluid. The tube register comprises parallel capillary tubes (1) which are folded in layers. The spaces between the capillary tubes are filled with foam (2), thereby producing a large heat exchange surface. Said heat exchanger is preferably used in cooling towers.
