Abstract: An improved design of a vapor compression distiller which makes use of a rapid, highly turbulent flow through the heat-of-evaporation recovery, or primary, heat exchanger. The distiller may also include the use of turbulators to increase turbulence and mixing within the primary heat exchanger. The increased level of turbulence and mixing dramatically reduces fouling inside the primary heat exchanger and increases the heat transfer efficiency. The improvements in the distiller are maximized by recirculating the liquid to be evaporated at a high multiple of the flow rate of the liquid feed to the distiller. The distiller may also include a feed circulation loop with a secondary heat exchanger to increase the efficiency of heat-of-evaporation recovery in the evaporation/condensation cycle. Applications of the vapor compression distiller include purification of waste liquids, concentration of dilute liquid mixtures, and separation of liquid/liquid, liquid/gas, and liquid/solid mixtures.