Evaporator, especially for discharging waste heat

An evaporating apparatus for transferring a working fluid from its liquid state into its vapor state, especially for systems for discharging of waste heat from a space flight body, comprising at least one vaporizing unit having at least one vaporizing element enclosing a liquid space for holding an evaporable working fluid and a vapor space wherein said evaporable working fluid is evaporated, capillary separation means for separating said liquid space from said vapor space and for passing said evaporable working fluid by capillary action from said liquid space to said vapor space, first means forming primary channels in said vapor space, said primary channels being arranged along said capillary separation means, second means forming secondary channels in surfaces of walls of said vapor space facing said capillary separation means, and hollow third means for communicating said secondary channels with said primary channels through said hollow third means for an efficient vapor removal from said vapor space, said primary and secondary channels extending approximately perpendicularly to each other and means for applying heat to evaporate said evaporable working fluid.