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Feature
• Zoning : AHUs allow for diversification within building , meaning one can control different areas independently . This saves energy by not conditioning air in unused spaces .
• Fresh air integration : Fresh air can be mixed with return air in a mixing box to improve IAQ and prevent unpleasant odours .
• Customisation : AHUs can be customised for each application , tailored to the specific needs , thus having great flexibility .
However , AHUs also come with a number of challenges , the first being space requirements , he says : AHUs require significant floor space ( plantrooms ). The large requirement for ducting in risers ( shafts ) and in ceilings also demands significant space .
“ Regular maintenance is crucial to keep AHUs operating at peak performance , preventing issues that can compromise their effectiveness . One of the primary aspects of AHU maintenance is establishing a regular schedule for upkeep . Depending on the specific application , monthly maintenance is often recommended to address critical components . This routine check ensures the longevity and optimal functionality of the AHU , preventing potential breakdowns and system inefficiencies .”
He lists the key components of maintenance within regular checks as follows :
• Air filters : As the first line of defence against airborne particles , filters require close attention . Monthly inspections involve checking for dust and pollutants , promptly cleaning or replacing filters to maintain a clean airstream . Clogged filters can compromise the efficiency of the coil , hindering its ability to cool the air effectively .
• Coils : Regular inspection of coils is essential to prevent clogging and maintain their effectiveness . Failure to replace filters can lead to particles adhering to cold coils with condensation , reducing the unit ' s thermodynamic efficiency . Monthly checks ensure coils remain unobstructed and perform optimally .
• Drain pan : The drain pan beneath the coil must be cleaned regularly to avoid blockages . Debris , such as food wrappers or packets ( erroneously left inside the unit ), can obstruct drainage , leading to overflow and potential damage . This simple yet crucial task prevents water damage within the unit .
• Electrical components : For units with additional components like electric heating or humidifiers , a thorough visual check is recommended , as well as of
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RACA Journal I March 2024 www . refrigerationandaircon . co . za