Summary:

An air handler, or air handling unit, is a device used to regulate and circulate air as part of a heating, ventilating, and air-conditioning system. The basic function of the AHU is to take in outside air, re-condition it and supply it as fresh air to a building. While managing various building systems, the automation system ensures the operational performance of the facility as well as the comfort and safety of building occupants.

Solution:

The AHU consists of:

1. Blower section
2. Duct system
3. Fan section
4. Filter section
5. Motor section
6. DX Heating/cooling coil
The basic function of the AHU takes in outside air, condition it and supply fresh air to a building. All exhaust air is discharged, which secures an acceptable indoor air quality. Depending on the required temperature of the conditioned air, the fresh air is either heated by a recovery unit or heating coil, or cooled by a cooling coil.

In buildings, where the hygienic requirements for air quality are lower, some of the air from the rooms can be re-circulated by a mixing chamber, and result in significant energy savings. A mixing chamber has dampers for controlling the ratio between the return, outside, and exhaust air.

The AHU is a large metal box containing separate ventilators for supply and exhaust, heating coil, cooling coil, heating/cooling recovery system, air filter racks or chambers, sound attenuators, mixing chamber, and dampers. AHUs connect to ductwork that distributes the conditioned air through the building, and returns it to the AHU.

For automating the AHU system, we have used PLC, HMI and sensors for control and Monitor the AHU. If any parameter goes beyond its set value an alarm will be popped and the system will go into the off state till the problem is not resolved. And report will be generated shift-wise, weekly and monthly to know how the system is working and when the system has to be serviced.