An apparatus for generating purified liquid from an input liquid, comprises, an evaporation chamber flooded with the input liquid and wherein the evaporation chamber generates saturated gases and comprises a shared wall with the condensation chamber and wherein the evaporation chamber is configured to generate evaporation cavities and condensation cavities on respective sides of the shared wall for a 2-phase counter flow of a liquid phase component and a gaseous phase component in composite flows for a 2-phase to 2-phase direct latent heat exchange. A condensation chamber has channels disposed in the input liquid, wherein liquid-saturated gases are generated therefrom in the evaporation chamber. The apparatus is operated as a four-port counter-flow heat exchanger where two different fluids are exchanging heat based on the inlet ports of both fluids being on opposite sides and the outlet ports of both fluids are also on opposite sides of the evaporator and condenser.