Heat transfer surface with multiple layers

Claim 1

In a heat transfer wall for transferring heat from an inner side of said wall to an outer side thereof by phase-converting a liquid brought into contact with said outer side of the wall, said heat transfer wall having a number of cells arranged regularly in an outer surface region of said wall and a plurality of independent holes for allowing the cells to communicate with the outer side of the heat transfer wall, said heat transfer wall characterized by comprising a plurality of layers of elongated cells, the layers being arranged adjacent one another along a direction from the outer side of said wall toward the inner side thereof, the individual cells of each layer of cells being partitioned from one another by side walls which extend generally along the direction of heat transfer through said wall and in a direction transverse to said inner and outer sides of said wall, a plurality of first holes for allowing the cells of the layer of cells closed to the outer side of said wall and the cells of the layer next closest to the outer side of said wall to communicate with each other, and a plurality of second holes for allowing the cells of the layer of cells closest to the outer side of said wall to communicate with the outer side of said heat transfer wall, and wherein the height of each of said cells is at least 0.15 mm.