Simulation of the thermosyphon free cooling mode in an integrated system of mechanical refrigeration and thermosyphon for data centers

Integrated system of mechanical refrigeration and thermosyphon (ISMT) is an ideal solution for energy-saving of data centers. The performance of the thermosyphon mode of an ISMT is very important and has great effect on its annual energy-saving rate. To investigate and optimize the performance of the thermosyphon mode, a distributed-parameter model is built and verified by experimental results. With this model, the performance of different air flow rate and geometric parameters is studied. The results show that the cooling capacity and circulation flow rate both increase with air flow rate and riser diameter, and decrease with tube length. Combined with these performance simulation results, the annual working time of thermosyphon mode is also calculated for a small data center in Beijing. The method to achieve the optimal design is given for different design requirements. (C) 2015 The Authors. Published by Elsevier Ltd.