Cleaning of Heat Exchange Coils

Coils are used in a number of different applications in HVAC systems to transfer heat either into or out of air streams.

There are two basic types of coils:

  1. Condenser Coils - Condenser coils transfer heat into a space. Refrigerant vapor is forced into the coil under pressure, condensing the refrigerant into a liquid, which results in the rejection of heat across the heat exchange surface.
  2. Evaporator Coils - Evaporator coils do the opposite of condenser coils. Liquid refrigerant is pumped into a low pressure coil, causing the refrigerant to evaporate into a vapor, absorbing heat across the heat exchange surface in the process.

Over time the surfaces of these coils can become dirty as the air moving over the coils can contain dust, dirt, pollen, moisture and other contaminants. A build-up of contaminants decreases the available surface area for heat transfer, reducing the efficiency of the heat transfer process, leading to excessive energy consumption and poor system performance. EPSCO Envirotech regularly inspects and maintains air conditioner coils to ensure they operate at optimum efficiency. In addition to the energy efficiency and system performance benefits, regular coil cleaning also improves equipment life spans and indoor air quality.

Energy Efficiency

Dirty condenser and evaporative coils have a negative impact on energy efficient HVAC system operations. A dirty condenser coil can increase compressor energy consumption by 30%. A dirty evaporative coil will decrease airflow which reduces heat transfer thereby degrading the de-humidification process.

System Performance

Poor heat exchange of coils reduces system performance meaning air conditioning is less able to cope with extreme ambient conditions.

Equipment Life Cycle

Poorly performing coils also mean that other parts of the air conditioning system have to work harder or for longer resulting in reduced life cycles. With refrigerated air conditioning systems, compressors have to work harder and longer to achieve the required system performance. Poor coil performance in these systems can also lead to other problems that either reduce compressor life or in some circumstances cause catastrophic compressor failure. Likewise with water based systems, with decreased coil performance chillers, boilers and pumps all have to work harder. In addition, biological growth on coils can lead to corrosion that over time will significantly reduce the coils’ performance to a point where they will need to be replaced.

Indoor Air Quality

In cooling coils the conditions often exist for the growth of microbiological contaminants. Contaminants, such as bacteria, mold, fungi can create colonies on the cooling coils of the AC systems creating toxic allergenic organic fragments known collectively as Macro molecular Organic Dust. This has been linked with various health complaints in buildings. The build up of contaminants also reduces heat transfer effectiveness and system efficiency. Regular cleaning by EPSCO team minimises this build up.

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