Working Principle for a Multiple Effect Evaporator Evaporation is used for subtlety different purposes and with different results in each industry. In the food processing industry, food products are concentrated to increase their shelf life, reduce volume and weight, reduce storage costs, reduce transportation costs, and increase value. If the water vapor from the first effect of a ​multiple-effect evaporator can be introduced into the steam chest of a second effect operating at a lower boiling point, the latent heat in the water vapor can be reused. Lowering the vapor pressure of the second effect relative to the first effect lowers the boiling point of the second effect. This arrangement of reusing vapor latent heat is called multiple-effect evaporation. A ​Multiple-Effect Evaporator System uses the water vapor from one effect as the heating medium for the next effect, which operates at a lower boiling point. The latent heat in water vapor can also be reused by thermally or mechanically compressing the vapor to a higher pressure and temperature. The multiple-effect configuration combines two or more evaporator bodies to conserve steam, which is condensed in the first-effect heat exchanger only. Water evaporated in the first-effect vapor body is condensed in the second-effect heat exchanger, which provides energy for evaporation in the second-effect vapor body (and so on for additional effects). Vapor from the last effect flows to a condenser.
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