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Air Handling Unit or Air handler OR AHU

Air Handling Unit






FUNCTION:

The AHU is designed to circulate the air in the area after passing it through 10/20 micron fresh air filter, 10/5 micron pre filter, 5/3 micron fine filter, 3/1 micron fine filter and 0.3 micron HEPA filter to achieve a clean class as per desined. The air in-take and out-take of the system is designed to maintain certain degree of pressure gradient in the area as per the requirement. To generate the required CFM and static pressure, appropriate motor capacity and blower is considered.

The major components of the air handling units are briefly described as below:

5.0 

6.0 AIR HANDLING SYSTEM: 

  •         Supply Blower: Supply blower is provided in the unit to supply air in the working area. This blower is belt driven by a motor. The blower takes the air from the atmosphere and delivers it to the working areas through air distribution network.

 AIR CONDITIONING SYSTEM: 

  •             Cooling Coil: Cooling coil of water cooled type provided in the AHU for temperature controlled process rooms, the cooling is achieved by the heat transfer between the cooling coil and coil surface/fins.    
  • Heating Coil: Heating coils are provided in AHU for controlling Relative humidity as well as temperature of process rooms. the heating is achieved by the heat transfer between the heating coil and coil surface/fins.                                                                            

 AIR DISTRIBUTION SYSTEM:

  • Air Distribution Network: An air distribution network is provided to supply the air delivered by the blowers into the working areas through extensive G.I. ducting with necessary volume control dampers into the supply terminal modules. And return air is picked up from the return grills sucked back through the air handling unit.  

 AIR FILTRATION SYSTEM:

  • Fresh Air Filter: Fresh air filter having efficiency up to 80-90% down to 20 or 10m is provided in the air handling unit of flange type or box type as per AHU design

  • Pre filter: Pre filters having filtration efficiency up to 85 to 90% down to 10 or 5m are provided in the air handling unit of flange type and HDPE media.

  • Fine Filters: Fine filters of 5 or 3 or 1 micron having filtration efficiency up to 95% down to 5m and fine filters having filtration efficiency 97% down to 3m  provided after cooling coil provisional space to remove fine particles from treated air.

  • Plenum or Terminal HEPA filters: HEPA filters having filtration efficiency up to 99.97% down to 0.3m provided in the Plenum or terminal modules.

  •   TERMINAL UNIT: Filter terminal modules (FTM): HFTM has been placed at the ceiling level to achieve desired ISO class conditions in the area with a provision for to fit GI powder coated and with volume control damper. The modules is designed and fabricated to install a flange type 10m filter with gaskets.

  •            RETURN RISERS: Every room has been provided with return air riser made of GI powder coated sheet and with a volume control damper with 10 or 20m filters.

SAFETY SYSTEM: The AHU is provided with limit switches, interlocked with blowers and access doors. If any access door to blower is opened, respective blower will be switched off automatically.

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