Abstract: We experimentally addressed the air extraction,from a large sized condenser of thermal power-plant with the pumping units comprising steam-jet and/or water-ring vacuum pumps,via case-study for the possible energy-saving solution.The influence of the pumping conditions,including,but not limited to the power-load,leakage-rate of condenser and temperature of circulating water,on the heat transfer coefficient and energy consumption,was investigated.The preliminary results show that the pumping conditions all have a major impact.To be specific,when it comes to energy-saving,the steam-jet pump significantly outperforms the water-ring pump,only under the specific pumping conditions,including a larger leakage-rate of condenser,a higher temperature of circulation-water and a lower power-load.We suggest that depending on the specific situation,steam-jet vacuum pump may not be a good energy-saving solution for all thermal power plants.