They also reduce the chances of harmful bacteria from multiplying within the unit.
AIR HANDLING UNIT BASICS FREE
Mechanical filtration systems remove airborne particle pollutants such as dust, pollen and pet dander from the air and fix them to a fibrous filter.įilters help to keep the AHU itself clean and free from material that may congest the mechanism. The most common type of filtration used by an AHU is mechanical filtration. An AHU consists of a combination of the following: Air filtersĪir filters are used to remove common airborne pollutants, both particulate matter and gaseous, from the atmosphere. The purpose of an AHU is to achieve better indoor air quality. It’s worth noting that not all HVAC systems will have all these components, rather it is an umbrella term that relates to the interconnected and interrelated air control systems.
An HVAC unit may comprise any combination of: HVAC systems come in all shapes and sizes but are generally large systems that require a dedicated room or outdoor space. It also provides a source of ventilation to allow moisture to escape. HVAC is responsible for the heating and cooling of buildings. The air handling unit, or AHU is part of the HVAC system and is a machine that is designed to handle and condition the air that is processed in the HVAC system. HVAC systems are usually relatively large installations that are used to condition the atmosphere in both residential and commercial buildings using the principles of fluid mechanics, thermodynamics, and heat transfer. The heating, ventilating and air conditioning system, or HVAC focuses on environmental comfort. © Eurovent © Eurovent Certita Certification Are they interchangeable or are they completely separate entities? While they may sound different, the truth is there is some crossover with what an air handling unit (AHU) is and what a heating, ventilating and air conditioning (HVAC) system does. The blower may operate at a single speed, offer a variety of set speeds, or be driven by a to allow a wide range of rates.If you’re part of the industry, you’ll have heard the terms AHU and HVAC mentioned. Main articles: andAir handlers typically employ a large driven by an AC induction to move the air.
This type of humidifier can quickly clog if the primary air filtration is not maintained in good order.Mixing chamber. As the air passes through the medium it entrains the water in fine droplets.
AIR HANDLING UNIT BASICS SERIES
Wetted medium: A fine fibrous medium in the airstream is kept moist with fresh water from a header pipe with a series of small outlets. The rate of evaporation can be increased by spraying the water onto baffles in the air stream.: steam or vapor from a boiler is blown directly into the air stream.: water is diffused either by a nozzle or other mechanical means into fine droplets and carried by the air.: A tray of fresh water in the airstream is excited by an ultrasonic device forming a fog or water mist. Various types of humidification may be used.: dry air blown over a reservoir will evaporate some of the water. This may be done by means of a visual display using a pressure gauge, or by a pressure switch linked to an alarm point on the building control system. The panel filter is cheaper to replace and maintain, and thus protects the more expensive bag filters.The life of a filter may be assessed by monitoring the pressure drop through the filter medium at design air volume flow rate. Depending upon the grade of filtration required, typically filters will be arranged in two (or more) successive banks with a coarse-grade panel filter provided in front of a fine-grade bag filter, or other 'final' filtration medium. Gas-phase and ultraviolet air treatments may be employed as well.Filtration is typically placed first in the AHU in order to keep all the downstream components clean. It may be via simple pleated media, or a combination of techniques. A RTU inside with supply ventsAir filtration is almost always present in order to provide clean dust-free air to the building occupants. Larger air handlers may be several meters long and are manufactured in a sectional manner and therefore, for strength and rigidity, steel section base rails are provided under the unit.Where supply and extract air is required in equal proportions for a balanced ventilation system, it is common for the supply and extract air handlers to be joined together, either in a side-by-side or a stacked configuration.Components The major types of components are described here in approximate order, from the return duct (input to the AHU), through the unit, to the supply duct (AHU output).
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