To improve the energy efficiency of supercomputer center, a novel energy system aimed at enhancing cooling efficiency while reusing waste heat is proposed. The energy system integrates a plug-type spray cooling system with a two-stage absorption chiller driven by spray cooling waste heat. Overall modeling of integrated energy system is analyzed based on spray cooling model and absorption chiller model. Energy saving evaluation is conducted based on Dawning 5000A supercomputer in China. It is found that the novel energy system is much efficient than the original energy system in all seasons. The energy saving effect is highly affected by inlet temperature of spray cooling. With the increase of inlet temperature, the spray cooling capacity decreases while the absorption cooling capacity increases. Thus, an optimal inlet temperature of 55 degrees C is obtained at which the lowest cooling power consumption, lowest power utilization effectiveness (PUE) and highest energy saving efficiency (ESE) can be achieved. Taken Dawning 5000A supercomputer for example, the system can achieve ESE as high as 49% and PUE within best practice scenario of 1.44. At the optimal design, cooling power consumption only accounts for 16%. Power consumption devoted to running the IT equipment is improved from 60% to 67%. (C) 2017 Elsevier Ltd. All rights reserved.