In a bubble-column vapor mixture condenser, a fluid source supplies a carrier-gas stream including a condensable fluid in vapor phase. The condensable fluid in liquid form is contained as a bath in a chamber in each stage of the condenser, and the carrier gas is bubbled through the bath to condense the fluid into the bath. Energy from condensation is recovered to a liquid composition in a conduit that passes through the liquid in the stages of the condenser. The bubble-column vapor mixture condenser can be used, e.g., in a humidification-dehumidification system for purifying a liquid, such as water.