When the evaporator coil of an air conditioning system is covered with ice, the efficiency of the whole system usually suffers. This is because the layer of ice usually forms an insulating layer. It literally introduces another layer between the liquid refrigerant and the warm air passing over the coils. Add to this the fact that ice is a poor conductor of heat and you will end up with an inefficient heat transfer process that then reduces the cooling effect that the evaporating refrigerant has on the passing air.
The accumulation of dirt in an air conditioning system is one of the major causes of icing. Here is what you should know about the effect that dirt has on your air conditioning system's coils.
Dirt and restricted air flow
By trapping dust and mold particles from the air that enters an air conditioning system, air filters guarantee not only good air quality in a home, but also a dirt-free air conditioner. The problem is that in the course of doing this, the filters usually get clogged with dirt. And since clogged air filters cannot let in as much air as they should, this usually leads to restricted airflow over the evaporating coils.
Another way through which dirt accumulation can affect an air conditioner's airflow is by affecting the functioning of the system's blower fans. The accumulation of dirt on the blades can significantly change the shape of the blades. This will then affect the capacity of the blades to push air through the system at any given time, hence resulting in less-than-normal airflow over the evaporator coils.
Restricted airflow and coil icing problems
Air conditioning systems usually cool air by taking advantage of the ease with which a refrigerant can change states. At the evaporator coil, the refrigerant usually changes from a liquid to a gas. This process involves the absorption of heat, something that then creates the cooling effect necessary to make your home comfortable.
When designing an air conditioning system, manufacturers have to do a balancing act in order to ensure that the air conditioner can cool air without freezing the resulting condensate – something that usually leads to a drop in air conditioning efficiency. To this end, they usually consider the heat of the air flowing over the coils.
A problem will therefore arise in cases where there is restricted airflow. Why? Because the air flowing over the coils won't be able to provide enough heat to counteract the cooling effect of the refrigerant. The evaporator coil area will therefore end up with temperatures that are low enough to not only condense, but also freeze the moisture in the air passing over the coils hence your air conditioner icing problems.
Given the effect that dirt accumulation can have on your system, it is advisable that you not only clean your air filters regularly, but also change them after every 3 months. Doing so will go a long way towards eliminating the efficiency problems that are usually caused by dirt accumulation.
For more information and assistance with repair and maintenance, contact an HVAC servicing company, such as Pristine Air Conditioning Corp.