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Feature
AHUS : THE HEART OF HVAC SYSTEMS
The following is a Q & A prepared by Preggy Chettiar , HC Group of Companies : business development .
Images supplied by HC Group of Companies
An Air Handling Unit ( AHU ) is the heart of numerous heating , ventilation and air-conditioning ( HVAC ) systems . This plenum box plays a crucial role in treating the air to attain the desired levels of filtration , heating , cooling , humidity and air sanitisation . 1 . What is the importance of air handling units in central air-conditioning systems ? AHUs are vital components in central air conditioning systems , ensuring optimal air quality , precise temperature and humidity control , energy efficiency and occupant comfort at an economical cost .
2 . The importance air handling units play in indoor air quality AHUs play a crucial role in creating and maintaining healthy indoor environments by filtering out contaminants , bringing in fresh air , and controlling temperature and humidity . This is particularly vital in modern buildings with tighter construction and limited natural ventilation .
Investing in a well-maintained and adequately configured AHU can significantly benefit building owners and occupants regarding
Vertical AHU . health , comfort and productivity . AHUs enhance indoor air quality through multi-stage filtration , effectively capturing dust , viruses and VOCs . Controlled ventilation not only brings in fresh air but also optimises efficiency , positively impacting overall wellbeing and productivity .
3 . The basic AHU configuration and its different components The air handling unit is an integral part of central air conditioning systems . It can be configured in various permutations to include primary and secondary HEPA filters , cooling coils , heating coils , humidifiers , dehumidifiers , supply air fans , return air fans , exhaust air fans , air-to-air heat exchangers , heat recovery wheels , dampers , etc . The psychrometric process and the indoor air quality the design engineer aims to achieve will ultimately determine the AHU configuration .
4 . How a custom AHU is designed and built Designing a custom-built AHU involves a systematic engineering process comprised of sequential steps : i . Design and planning
• Define requirements : Understand the application needs , considering airflow rate , temperature and humidity control , space constraints , budget and maintenance accessibility . ii . AHU design
• Select components : Choose components such as fans , coils , filters , dampers , controls and housing based on defined requirements , emphasising energy efficiency to minimise life cycle costs .
• Create detailed design : Develop a comprehensive design for the AHU , including drawings , specifications and calculations . iii . Housing construction
• Design structural base : Design the structural steel base to meet deflection standards and apply site-specific corrosion treatment .
• Construct housing : Utilise double-skinned panels with insulation ( e . g ., polystyrene , polyurethane , polyisocyanurate , rock wool ) for the AHU housing . Smaller commercial units may use single-skin powdercoated panels with insulation .
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RACA Journal I March 2024 www . refrigerationandaircon . co . za