Nordics Prototype Data Hall Free Cooling Design

Abstract

With the global rise in data center developments where Rack Densities keep rising and demanding more power and accordingly more cooling to reject the increased heat, optimizing energy efficiency and reducing power consumption are paramount. This study investigates an innovative cooling approach leveraging dry coolers and ice Thermal Storage tank systems to enhance data center performance, particularly in cold climates such as Nordics, specifically in this study the city of Pyhajoki in Finland.

Traditional Air-Cooled Chillers (ACCH) dominate cooling infrastructure but consume significant power due to compressors and refrigerants circuits. Dry coolers, on the other hand consisting only of fans and heat exchangers, provide a more sustainable alternative, operating efficiently without refrigerants. However, their cooling capacity is limited by ambient temperature, restricting their standalone use.

The proposed hybrid system integrates dry air coolers with ice tanks to capitalize on Finland’s low temperatures, where 96% of the year remains below 20°C. In cold conditions, dry air coolers handle the entire data center cooling load while simultaneously freezing ice tanks. During warmer periods (above 20°C), the ice tanks discharge, maintaining the required supply temperature for fan wall units to cool the Data Halls within ASHRAE Class A Racks (29°C Server inlet Temperature) without relying on chillers. This configuration omits chiller operation all over the year and allow for full free cooling during the 4% of the year, significantly reducing power consumption and supporting sustainability initiatives. The results demonstrate that this system achieves substantial energy savings, enhanced mechanical efficiency and lower environmental impact.