Critical temperature of free cooling using indirect opening cooling tower in data centres: a review

The energy consumption of data centres is increasing rapidly. The key to energy saving in the data centre is to reduce cooling energy consumption, resulting from 30-50% of the total power consumption in the data centre. The free cooling of the cooling tower is a significant method to reduce cooling energy consumption. Determining a reasonable critical temperature of free cooling can extend the free cooling time, which is significant for energy saving. In this study, an overview of the current status and affecting factors of the critical temperature had discussed. Chilled water supply temperature and cooling approach are the key factors of critical temperature and are analysed. Further, this review proposes an effective method to obtain the critical temperature of free cooling.