Energy efficiency and economic analysis of utilizing magnetic bearing chillers for the cooling of data centers

Recently, with the rapid construction of data centers in China, the server installed ratios of new data centers are generally small in the early stage, which makes the cooling systems usually operate under the part cooling load conditions. Therefore, it is significant to select chillers that can operate efficiently with part load ratios. However, while the magnetic bearing chillers have been proven high efficiency chillers under part load conditions in the previous studies, the application of magnetic bearing chillers in the data centers has not been investigated clearly. In this paper, the energy performance and economy of utilizing the magnetic bearing chiller for the cooling of the data center are simulated and compared with that of the traditional centrifugal chiller and scroll chiller comprehensively. The simulation model is validated by the field test results. Furthermore, the energy efficiency of the data center cooled by the magnetic bearing chiller is discussed according to the long-term monitoring data of a small-scale data center of a university in Nanjing China. The results show that the average COP of the magnetic bearing chiller varies from 8 to 10 under different load conditions, which is much higher than that of the traditional centrifugal chiller and the scroll chiller especially when the server installed ratio of the data center is lower than 50%. The energy saving rate of the magnetic bearing chiller are approximately 10%~40% compared with the traditional centrifugal chiller and the scroll chiller. In terms of economy, the initial investment of the magnetic bearing chiller is much higher than that of the traditional centrifugal chiller and scroll chiller while the operation cost of the magnetic bearing chiller is the lowest. This study benefits the selection of chillers for this kind of small-scale data centers.