Only a portion of the vapor from an evaporator can be compressed in a thermocompressor with the remainder condensed in the next-effect heat exchanger or a condenser. A thermocompressor is normally used on a single-effect evaporator or on the first effect of a double- or triple-effect evaporator to reduce energy consumption. Like mechanical recompression, thermal recompression is more applicable to low boiling-point rise liquids and low to moderate differential temperatures in the heat exchanger to minimize the compression ratio.

The double-effect evaporator with thermal recompression requires 33% less steam than the conventional double effect. In essence, the steam usage for the double effect with thermal recompression is comparable to that of a triple-effect evaporator.