Coil cleaning

Let's get cooling coils into perspective!

• An average air conditioning cooling coil, 150 mm deep, operating 10 hours per day would see approximately 100,000 metres of air go over any point on that coil's fin surface in one day.
• Comparing the area of the coil to the floor area served by the coil and if the floor was cleaned twice a week and the coil once a year, then there would be 100 times more attention paid to the floor than to the coil.
• Most floors are dry 99.9% of the time, but most cooling coils are wet an estimated 90% of the time. In wet conditions it takes 24 to 32 hours for most mould spores to germinate.

Hence assuming average filtration and particulate load, the total load of debris handled by a commercial HVAC system in one day of operation is significant. Based on these rough facts it?s obvious that cooling coils get far less attention than the typical commercial office carpet, yet these systems are exposed to huge amounts of dirt and debris even with decent filters.

The human respiratory system is less able to deal with airborne contaminants than the digestive system to deal with swallowed contaminants. And yet we continue to breathe air that passes through a cooling coil without a passing thought.

When the material still resident in coils is tested, it's almost always biologically active - meaning it is alive with multiplying organisms that live in the wonderful, nutrient-rich wet atmosphere that a cooling coil provides.

When to clean?

• Good cleaning procedures have to start when coils are put into operation, not two or three years down the road! Modern coil design means that with coils that are over 4 rows deep and have suffered from neglect, then it will be almost impossible to properly clean the middle rows of the coil. In this instance it is sometimes cheaper to replace the coil.
• And do not forget to upgrade the filters.
• after all that is the main reason that the coil requires cleaning in the first place. Coil before and after cleaning.

Advantages

• A dirty coil has a greater pressure drop and hence more fan energy is required to drive the airflow. A clean coil will save energy.
• The indoor air quality will be improved with a clean coil.