Abstract: The purpose of the method developed is to form on top of a heat transfer surface a porous surface layer, which is to be fixed to the surface below it at a temperature and time applicable for industrial production. The heat transfer surface is copper or copper alloy. The powder forming a porous surface is fine-grained copper oxide powder, which is reduced to metallic copper on the heat transfer surface during heat treatment. The invention also relates to the heat transfer surface of copper or copper alloy, on which a porous layer has been formed from metallic copper, which is manufactured by reducing copper oxide powder and is attached using brazing solder.

Abstract: A heat transfer tube having surface enhancements so as to improve the thermal performance and increase the heat transfer capacity. The heat transfer tube has an inner surface having a layer of sintered, soldered or brazed metal powder thereon.