Abstract: A boiler/condenser assembly for a high efficiency purification system including a plate-in-frame type heat exchanger wherein vertically extending common plate members are provided with corrugated faces having herringbone configurations constructed and arranged to provide a plurality of contact points where the condensing surfaces of adjacent common plate members defining a condensing chamber come into near or direct contact which serve as accumulation points for the liquid forming on the condensing surfaces of both common plate members. The accumulated liquid is caused to flow off the condensing surfaces in a plurality of diagonal liquid flow paths.

Abstract: A vapor compression distillation system including a boiler/condenser assembly wherein a portion of the condensate is redirected back to the condenser inlet to extract superheat from the compressed vapor and transfer it to the liquid in the boiler. The vapor entering the condenser is reduced to a saturation condition to prevent heat build up in the condenser to improve heat transfer efficiency. When the temperature of the incoming feed water is within the operating range of the boiler/condenser assembly, the system is operated under vacuum sufficient to match the boiler temperature with the temperature of the incoming feed water so that no preheater or waste heat recovery exchanges are required.