Modern chillers are designed to work
with very little fouling on the condenser tubes. A layer of scale or dust 1.6mm
thick on the condenser tubes of a high efficiency centrifugal chiller will
increase electrical consumption by 14%.
However, biofilm is an even greater problem.
This slimy substance formed on heat transfer surfaces by water-borne bacteria, creates
4-5 times more insulation than the calcium carbonate scale. A biofilm
layer 1.6mm thick increases electrical usage by as much as 35% and can
cause the equipment to shut down.
Microbiological activity is at its
peak during the summer months when the bacteria can flourish. It can cause corrosion
and promote legionella growth.
As air is pulled through the
condenser coil, small amounts of dirt will be deposited on the fins.
If this is not treated the dirt will
build up over time and create an insulating blanket which will restrict
airflow. This prevents effective heat transfer and the system has to work
harder to dissipate the heat.
Studies indicate that the contamination
of the condenser and evaporator coils can increase your system’s energy
consumption by as much as 36%.
Clean condensers are essential for the
effective operation of any refrigeration system and the compressor is the
largest single energy user in any system.
Keeping coils clean will provide the
most significant efficiency gains. Dirt build-up, on either condensers or
evaporators, increases the difference between condensing and evaporating
temperatures.
Every 1°C increase raises
refrigeration costs by 2-4%.
Typically, coils are cleaned
regularly using a product which can also sanitise degrease
and prevent corrosion.
Coil cleaning is an essential component of good maintenance. It should be completed regularly in accordance with the
level of contamination and biofilm build up.
The on cost should be recovered in
efficiency and can be improved by adding coil protecting electrostatic filters
to help prevent the contamination in the first place.
Using a RABScreen external filter
will keep the coils cleaner for longer and because of their low impact on
airflow you will get maximum energy saving benefit and reduce your carbon
footprint as well.
For more information visit http://www.rabscreen.com/learn-more1
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