Energy-efficient air conditioning system of a data processing center
Authors: Zharov Anton A. , Venevceva Darya A. , Mikita Guriy I. , Voronov Vladimir A. , Apsit Konstantin  A. 
Published: August 2023

BACKGROUND: Currently, because of the rapid development of digital technologies, an increasing amount of computer computing power is required where data processing centers are built, which sometimes require power consumption in the megawatt range. For stable year-round operation of data centers, reliable engineering is required, which includes air conditioning systems (ACS) for year-round use with a given level of reliability. Several traditional methods of data center cooling are available, namely, precision air conditioners based on vapor compression refrigeration machines (PCRMs) and systems with intermediate coolant (so-called chillerfancoil systems). However, in modern settings, when the required capacity of data centers increases every year and the framework for environmental friendliness and energy efficiency of installations becomes stricter, new, more energy-efficient, and environmentally friendly solutions for data center cooling is needed.
AIM: This study aims to compare the proposed energy-efficient ACS with combined vapor compres-sion and indirect-evaporative cycle with the most commonly used ACSs in data centers and to deter-mine the boundaries of transition between the operating modes of the proposed ACS in a data center operating in Moscow as an example.
METHODS: This study employs the following methods: analysis of existing data center cooling sys-tems, determination of a typical design set of outdoor air parameters in the region under consideration, and calculation by comparative analysis of the energy consumption of the proposed and traditional ACSs for data centers.
RESULTS: From our study, the different ACSs currently used for data centers, namely, precision air conditioners and chillerfancoil systems are highlighted. The main components of each system, the advantages and disadvantages observed in the design, installation, and commissioning processes, and the operation of the systems are described. An alternative ACS that combines PCRM and indirect-evaporative cooling is proposed. The comparative analysis of the proposed scheme and traditional so-lutions demonstrates that the combined ACS allows significant reduction in the energy consumption for data-center cooling. Therefore, under the conditions in Moscow, the proposed system for a particu-lar year will consume energy that is two times less than a chillerfancoil system with free cooling and 2.5 times less than a system with precision air conditioners that operate on the traditional vapor-compression cycles.
CONCLUSION: The comparative analysis of the proposed energy-efficient ACS with combined vapor compression and indirect-evaporative cycle with the most commonly used ACS in data centers con-firms its high energy efficiency and provides greater environmental safety. The boundaries of the tran-sition between the operating modes of the proposed ACS are determined in a data center that operates in Moscow as an example, which exhibits high energy efficiency and reliable operation.