A new method is proposed in this study to improve the entrainment performance of thermal vapor compressors (TVCs) that are widely used in multi-effect distillation (MED) desalination systems by preheating entrained vapor. In order to confirm its effectiveness and study the influences of the entrained vapor superheat on the TVC entrainment ratio, a four-effect-parallel-flow MED-TVC experimental system was set up. Hot water from a solar heating system and steam from an electric boiler were used as heat source of the entrained vapor preheating, respectively. The preliminary experimental results show that the entrained vapor preheating could greatly increase the TVC entrainment ratio and the TVC entrainment ratio increases with the entrained vapor superheat. Due to the poor performance of the TVC used in this study, further verification experiments of the proposed method need to be conducted in future work. (C) 2014 Elsevier B.V. All rights reserved.