Zur Entwicklung der Simulation in der DDR unter Einfluss des Prozessrechnereinsatzes.

A heat exchanger and method of making same, wherein elongated passageways are formed in unbonded portions of a blank made of bonded sheet material, and integral fins are formed on the sheet material with the fins having elongated base portions extending transversely to the length of said passageways. In certain embodiments the finned portions of the heat exchanger are so disposed relative to each other that fins therein project toward the adjacent finned portions.