Study of hot air recirculation and thermal management in data centers by using temperature rise distribution

One of the key challenges in reducing the energy consumption of data centers is to improve the efficiency of air conditioning units. The efficiency is increased when the temperature of the supply air rises; however, the hot air recirculation and hot spots may limit the rise of temperature of the supply air to ensure normal operation of servers. To solve this problem, the energy equation is modeled to separate the thermal influence of each server or rack, and the temperature rise distribution (TRD) is proposed to illustrate the recirculation efficiency in data centers. Based on the TRD, two recirculation ratios are suggested to evaluate the recirculation of each rack in the data center. An algorithm is suggested to optimize the power distribution among racks to minimize the maximum temperature inside the data center, reduce the number of hot spots, and provide more space for increasing the temperature of the supply air. The metrics and algorithm are tested and proved efficient by a computational fluid dynamics (CFD) case.