What Is an Air Handler?
An Air handler is air conditioning equipment installed in certain large facilities, such as large commercial buildings, offices, and schools. The function of the equipment is similar to that of air conditioners used in ordinary homes. However, they differ from ordinary air conditioners in that they are centrally controlled by a central management system.
Unlike air conditioners, air handlers do not require the installation of an indoor unit in each room, and thus have the advantage of requiring only the air handler to be maintained. If an air handler breaks down, there is a risk that the entire facility will be without air conditioning, so it is necessary to take measures to distribute the units and provide backups.
Uses of Air Handlers
Air handlers are installed in the following types of facilities that have an area used for a specific purpose.
- 3,000 square meters or more: offices, department stores, research facilities, etc.
- 8,000 square meters or more: school facilities, training centers, hotels, etc.
In such specified buildings the indoor environment of “temperature,” “relative humidity,” “carbon monoxide content,” “carbon dioxide content,” “suspended dust,” “formaldehyde content,” and “airflow” must be controlled under certain standards.
In addition, explosion-proof air handlers are used in industrial facilities that handle highly flammable substances or volatile gases.
How to choose Air Handlers
When considering the installation of an air handler, it is necessary to compare the required environment with the Building Sanitation Law and sanitation management standards.
The required equipment and the environment to be maintained differ between the air quality standards when air conditioning equipment is installed and the air quality standards when mechanical ventilation equipment is installed.
Air conditioning equipment refers to “equipment” and “all ancillary equipment” that can regulate and supply “temperature,” “humidity,” and “flow rate” by purifying air taken in from outside using “air filters” and “electrostatic precipitators, etc.”. In other words, it refers to equipment equipped with the four functions of “purification,” “temperature,” “humidity,” and “flow rate control.
Mechanical ventilation equipment refers to “equipment that purifies air, etc. taken in from outside and supplies it by adjusting its flow rate.” In other words, it is equipment that lacks the functions of “temperature control” and “humidity control” among the functions of air conditioning equipment.
When considering the installation of air handlers, it is necessary to take into account which of the above categories they belong to. If it falls under the category of air handlers, necessary sanitary measures must be taken to prevent air contamination by pathogens. Examples of applicable items include “equipment cleaning of cooling towers and cooling water” and “inspection and cleaning of humidification equipment.
Principle of Air Handlers
Air handlers consist of a “filter,” “blower,” “heat exchanger,” “heating unit,” or “cooling water coil.”
These parts are housed in a metal case and installed in a dedicated machine room.
Unlike ordinary air conditioners, water, not gas, is used as the refrigerant. Air handlers keep indoor air fresh by drawing in outside air along with the ring air from each room. The outside air is also taken in together to reduce the temperature difference between indoor and outdoor air to avoid unnecessary energy use. After that, the captured air is purified through filters. This cycle is repeated as the purified air is supplied to each room after its temperature is adjusted by a cold water coil for cooling and a hot water coil for heating.
Since the air handlers itself perform heat exchange in this way, there is no need to install outdoor units in each room if the system is installed in a basement or other location. This makes it possible to make effective use of the limited space in the building.
Since the range of functions and sanitary control standards required for each facility where air handlers are installed differs, options such as air purification and humidification functions are ordered from the manufacturer in the form of build-to-order production.