The following SAIRAC Cape Town centre tech talk presentation by Barry Leuverman, Netherlands-based export director at OXYCOM, is on sustainable cooling using water as a coolant, edited by Eamonn Ryan

A well-attended event in Cape Town.

A well-attended event in Cape Town. All Images supplied by Rozelle Steenkamp | SAIRAC Cape Town Centre

Most of us are familiar with cooling towers and adiabatic cooling, but our method at OXYCOM is slightly different. We have developed unique material and patented the entire process and product. Our company has been in operation for approximately 20 years, and while we are not a large manufacturer, we specialise in producing these material panels. The other activities involved in the manufacturing process are outsourced and we oversee the assembly of the final product. Additionally, we also provide a range of supplementary products.

Barry Leuverman, Netherlands-based export director at OXYCOM.

Barry Leuverman, Netherlands-based export director at OXYCOM.

Our system is designed to operate efficiently even with limited energy supply. We have tested our system using a normal generator, with the largest generator producing four kilowatts, and our system still provides sufficient cooling power of up to 35 kilowatts. For larger-scale applications, our system can provide up to 190-200 kilowatts of cooling.Indirect evaporative cooling systems have a media component located inside our equipment, and an external heat exchanger. Cold water passes through the heat exchanger, creating indirect contact between the water and air. This extra step enhances the cooling process and improves efficiency.The cold water passing through the exchanger indirectly cools the air, resulting in even lower temperatures. This is the essence of our innovative approach.Our evaporative cooling system works by keeping the air separate from the water. This means that we are able to lower the temperature and decrease the humidity in the air, which allows us to create a more comfortable environment. To achieve this, we use a two-part system: PreCooll which functions by direct adiabatic cooling, and IntrCooll which works with free cooling and ventilation with outside air. The first part ventilates the water supply, ensuring that the water does not get warm – This is important because warm water is not effective for cooling purposes. We cool down the water in the first half of the system to ensure that it stays at an optimal temperature. A supply fan ensures that the water remains cold and creates a high rate of evaporation. The material used in our system helps the water stick to the surface, increasing the evaporation process. The reflective surface of the system helps to maintain cool temperatures.When working on a project, we take into account various factors, including the weather data of the location. This helps us calculate the cooling power required and make the system more efficient. Water availability is also considered, as we aim to limit water usage while maintaining optimal cooling performance.

OXYCOM heat exchanger on display.

OXYCOM heat exchanger on display.

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, taking into account 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.

 

A satisfying conclusion.

A satisfying conclusion.

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