when the plant is operating in steady state, feed water at the cold inlet temperature flows, or is pumped, through the heat exchangers in the stages and warms up. when it reaches the brine heater it already has nearly the maximum temperature. in the heater, an amount of additional heat is added. after the heater, the water flows through valves back into the stages that have ever lower pressure and temperature. as it flows back through the stages the water is now called brine, to distinguish it from the inlet water. in each stage, as the brine enters, its temperature is above the boiling point at the pressure of the stage, and a small fraction of the brine water boils ("flashes") to steam thereby reducing the temperature until an equilibrium is reached. the resulting steam is a little hotter than the feed water in the heat exchanger. the steam cools and condenses against the heat exchanger tubes, thereby heating the feed water as described earlier.