The following is a presentation by Barry Leuverman, Netherlands-based export director at OXYCOM, on sustainable cooling using water as a coolant, edited by Eamonn Ryan. This is Part 2 of a two-part series.

Barry Leuverman, Netherlands-based export director at OXYCOM.

Barry Leuverman, Netherlands-based export director at OXYCOM. Images supplied by Rozelle Steenkamp | SAIRAC Cape Town Centre.

…continued from Part 1. 

Data centres and free cooling

Data centres with free cooling can achieve higher efficiencies, resulting in significant energy savings. By leveraging lower temperatures, these data centres can run for longer periods and operate more frequently.

There are two main paths for free cooling: direct and indirect. In a direct free cooling system, the outside air is filtered and brought inside without any additional influence. However, in situations where there is a lot of heat load inside a facility, it may be necessary to install a heat reclaim system to mix the outside air with the indoor heat and provide a more comfortable airflow while saving energy.

As for the indirect path, the system includes ventilators that work in conjunction with a panel that contains the necessary film material. The system also includes a tank that holds the water, which is mixed with evaporate and fresh water in a cycle. In the event of a power outage or shutdown, the drains automatically open to allow the water to flow out. The water inside the system remains, and when the system restarts, it will require water again. Calculations are done with weather data from the past, considering the worst conditions to ensure optimal performance.

The calculation takes into account the internal and external heat loads to determine the appropriate supply temperature. In some cases, a DX system may be necessary as a backup to ensure specific temperature requirements are met. The calculation also considers factors such as airflow, air changes and the comfort zone within the facility.

The outcome of the calculation provides information on the heat load, including the contributions from external factors such as sunlight. Water consumption is also calculated based on evaporation and drainage, considering water quality. The results can be used to determine the optimal temperature settings and the number of units required. Additionally, the calculation provides insights into the cooling hours and energy usage during different times of the day.

Overall, free cooling in data centres offers significant energy savings and can be optimised based on specific requirements and conditions.