Relating measured PUE to the cooling strategy and operating conditions through a review of a number of Maltese data centres

To deal with the heat generated by the information technology equipment hosted in data centres, dedicated cooling systems allowing the information technology systems to operate at their optimum thermal conditions continuously, are typically used. Being constantly in operation these cooling technologies have a large impact on the overall energy performance of these data centres. Based on this premise, the work presented in this research aims at gauging and comparing the real-life performance of three types of data centre cooling strategies found in just as many commercial data centres in Malta. Temperature and humidity logging was carried out to analyse the data centres operating conditions in conjunction with an analysis of the energy performance of the data centres themselves. A well know energy performance metric, the Power Usage Effectiveness, was used to enable the comparison of the energy performance of these data centres with one another. The results obtained revealed that whereas the use of computer room air conditioning is common in modern data centres, significant differences in energy performance can result from the specific application of such cooling systems, mostly related to the use or otherwise of physically segregated cold and hot aisle, the use of direct expansion cooling or air cooled chillers, and the use of direct or variable speed systems. Furthermore, the importance of air flow management in ensuring a uniform temperature throughout was observed through detailed temperature monitoring of one of the aisles in one of the data centres investigated.