A review on thermosyphon and its integrated system with vapor compression for free cooling of data centers

The increasing energy consumption of data centers has become a global concern. Over 30% of the total energy use in a data center is consumed by the cooling system and it is necessary to reduce this consumption by efficient cooling techniques. Free cooling is an alternative method, which means utilizing natural cold source when the outdoor temperature is lower than the indoor temperature to achieve energy-saving. Thermosyphon and its integrated system have distinct advantages over other free cooling methods and have great application potential. In this paper, the states of the art are reviewed and overviews are presented for thermosyphon and its integrated system, respectively. The features of existing designs are compared and shortcomings of current studies are concluded. This paper will be helpful for researchers in this field and promote the application of this new free cooling method.