Direct evaporative cooling, also known as direct adiabatic cooling or wet bulb cooling, is called direct as there is direct contact between the water and the air stream. During the direct evaporative cooling process, water is evaporated directly into the air stream that needs to be cooled down. This type of evaporative cooling is the most used form worldwide, especially in dry regions.
Disadvantages of direct evaporative cooling
One of the downsides of the direct evaporative cooling method is that when it is used for space cooling, it adds a lot of moisture to the air, causing the indoor climate to feel damp and clammy. Another disadvantage is that direct cooling is less efficient in regions where the outside relative humidity is higher. This is because the system can not evaporate water as efficiently when the air is already saturated.
To solve these issues, Oxycom developed its patented indirect/direct evaporative cooling technique. For more information on this two-stage cooling method, go to our page, 'two-stage evaporative cooling,' or check out the IntrCooll for more information on two-stage evaporative cooling for the industry.
Advantages of direct evaporative pre-cooling
Direct evaporative cooling is however very effective when used as pre-cooling for industrial chillers. This form of evaporative pre-cooling uses a contact humidifier (wet evaporative media) to cool down the incoming air before ventilating it through an air-cooled chiller. This increases the efficiency of the chiller considerably and will result in drastic energy savings.
Oxycom’s evaporative pre-cooling for chillers
Oxycom uses direct evaporative cooling in the PreCooll system, with which outside air is sucked through wetted Oxyvap® media, to cool down the incoming air and increase the efficiency of mechanical cooling installations. The Oxyvap® media contains the patented aluminum hydro chill fin technology reaching extreme efficiencies of 90 – 93% while having the lowest possible pressure drop of around 40 Pa at 2m/s (6,6 feet) per second.
The PreCooll is built around (the condensers of) the chiller and shades the condenser completely. The PreCooll creates a cool microclimate surrounding the condenser. In addition, the PreCooll is controlled by energy-saving software, taking into account local weather data and the water quality, and the thickening of the water during the cooling process. This way, adjustments are made automatically so that the chiller runs as efficiently as possible at the lowest possible energy costs. But perhaps the most important thing: with the PreCooll, you are always assured of the optimal operation of your chiller.