Simulation of a data center cooling system in an emergency situation

The paper deals with keeping server rooms at reasonable air temperature in the case of an electrical power failure in a data center and with building performance simulations used to support emergency power planning. An existing data center was analyzed in detail with respect to the possibilities of emergency cooling. Based on the assumption that the thermal capacity of already chilled water can be used to prolong functionality of the cooling system when the roof chillers are out of operation, a backup power supply was designed for Computer Room Air-Conditioning and even for the cooling liquid circuit pumps (i.e. not for the roof chillers). Special models representing the data center indoor environment and cooling system, including a detailed model of the Computer Room Air Conditioning (CRAC) units, were developed in order to estimate the time period during which the internal air temperatures in the server room will not exceed the limit. The numerical model of the server room and the cooling system was built in the TRNSYS software and calibrated by measured data acquired from a real power outage situation. The results and conclusions obtained from the performed analyses and simulations helped to improve the emergency power plan of the data center. The study also forms the basis for the development of an emergency decision algorithm that will included in the novel supervisory control platform: GENiC