Combined with the advantages of natural cooling technology and frequency conversion technology, thus effectively reducing the energy consumption of refrigeration system, the system of water-cooled multi-connected separate heat pipe system has been proposed for removing the heat and cooling the space in data rooms. This study is to explore the energy-saving potential of the water cooled MSHPS compared with that of the conventional air conditioning system. Firstly, a simplified thermal performance predicted model of the water cooled MSHPS is established and validated by experimental results, with a deviation of ±10%. Then, an energy consumption model of the water-cooled multi-split heat pipe system (MSHPS) (#3) is developed to determine the optimal supply air temperature and supply chilled water temperature set points, with temperatures of 24 C and 15 C respectively. Finally, the ESR of the water-cooled multi-split heat pipe system (MSHPS) (#3) over conventional CRAC with or without water side free cooling (#2 and #1) can be obtained by comparing annual energy consumption of cooling system #1~#3, with a percentage of 11.3% and 68.8 %, respectively.