• Existing recirculation AHU's with 55,000 CFM capacity vane axial fans
  were installed in 17'Wx40'L mechanical room.
  
• The facility was being upgraded to Class 10 level and air flow requirements
  is increased to 95,000 cfm.
  
• The existing filters and coils occupied the full width of the mechanical
  room and there was no additional space for adding more surface area.
  As such airflow could not be increased above 55,000 cfm.
  
• There was no space in the existing mechanical room for the additional
  auxiliary equipment required to support the new production equipment
  being installed.
  
• M&I Compac Space fan system can provide large volume flow system
  in much less footprint than conventional designs.
  
• Motorola contacted M&I to find a solution to their space problem.



• M&I faced various challenges when designing the system:

• Due to the location and dimensions of the supply shaft, the vertical
  upflow vane axial fan had to be located only 4 1/2" away from the wall.
  This space would not even allow the use of a standard inlet bell for
  the fan.
  
• Due to the limitation in the mechanical room width, the maximum width
  of the inlet flow concentrator was limited to 78"x84". The cooling coils
  were located only 10.5" from the inlet flow concentrator/silencer.
  
• Due to limitation in the mechanical room height, the maximum height
  of the inlet flow concentrator was limited to 96".
  
• The overall height and width of the filters/coils were selected to
  be much larger than the inlet flow concentrator height and width respectively
  in order not to exceed the maximum allowable air velocities across the
  filters/coils. The coils/filters were placed asymmetrically on three
  sides of the inlet flow concentrator while the fourth side (i.e. the
  wall sided) of the inlet flow concentrator was blocked off.
  
• Air entered the inlet flow concentrator at a velocity of 565 fpm and
  accelerated to the fan's annular velocity of 4,880 fpm (at the fan hub)
  within 10 1/2" distance from the edge of the inlet flow concentrator
  while undergoing a 90 degree turn.
  
• The inlet flow concentrator, coil/filter support structures and the
  fan roll-out rails were all built in multiple segments in order to be
  able to bring them into the mechanical room through the existing doors
  and corridors.
  
  

• The outlet silencer was made to match the space between the fan and
  the existing rectangular supply duct. The outlet silencer incorporated
  the transition plenum from round to rectangular shape.
  
• The outlet silencer was also built in multiple segments of 32" max.
  width in order to be able to bring it into the mechanical room through
  the existing doors and corridors.
  
• With these extreme limitations, M&I was able to achieve the following:
  
  
• Increased air flow from 55,000 cfm to 95,000 cfm.
  
• Achieved uniform air velocity across the filters/coils (less than
  5% variance) and turned the air sharply into the fan within a very short
  distance without causing any turbulence or flow separation which would
  affect the fan performance as well as cause vibration.
  
• Used only 20' length of the 40' long mechanical room. The remaining
  20'Lx17'W space was used to install the auxiliary manufacturing equipment
  that Motorola did not have any space for.
  
• Inlet flow concentrator, which also acts as a silencer, achieved substantial
  insertion losses, providing a very quiet operation.
  
• Outlet silencer gradually reduced the fan's annular velocity pressure
  to the duct entry velocity of 1,770 fpm. In the process, 80% of the
  fan's annular velocity pressure was regained, thus reducing the fan
  static pressure. Furthermore, the inlet flow concentrator had much less
  pressure than the existing conventional silencer, reducing the fan static
  pressure. This resulted in considerable reduction in the fan BHP.
  
  

• They were able to upgrade the facility to Class 10 level from Class
  100 since they were able to increase the capacity of recirculation AHU's
  to the required flow of 95,000 cfm.
  
• 340 sft of much needed space was recovered in mechanical room and
  put into use.
  
• Energy consumption of the fans was reduced by 25% due to aerodynamical
  design of the Compac Space system. This is a substantial savings since
  47% of the heatload in such facilities in contributed by the recirculation
  fans.
  
• The fan in the Compac Space system produced minimal vibration (less
  than 0.02 mil) requiring much less servicing than the fans used with
  the conventional design in this facility. Furthermore, the Compac space
  fan was allowed to be serviced while the fan was running, thus preventing
  costly shutdowns in the production area while the fans are being serviced.
  
  
• The modular design of the Compac Space system allowed them to bring
  the equipment into the mechanical room without necessity of enlarging
  doors or corridors. As a result, the installation could be done within
  a 24 hour period, which included the removal of the existing 55,000
  cfm system, and the production could be started without any downtime.
  
  
• Reduced mechanical room, coupled with reduced noise and vibration
  in the Compac Space fan, allowed the customer to use the full length of
  the clean room space thus adding additional 10 ft length to the production
  area.

Back View - click image for close up

Hz   W FAN   W INLET   W FAN CASING   W OUTLET   TL INLET   TL OUTLET 


63     92       87          81            85         5           7 


125    94       85          79            81         9          13 


250   100       85          87            77        15          23 


500    98       79          84            70        19          28 


1k     96       77          82            71        19          25 


2k     92       70          72            68        22          21 


4k     86       66          60            65        20          21 


8k     80       56          55            68        24          12 

            

Project: Motorola Inc.

BHP CALCULATION FOR M&I COMPAC SPACE FAN SYSTEM
WITH 95,000 CFM CAPACITY UNDER FINAL OPERATING CONDITIONS

Various static pressure losses and BHP calculation for the system under
the final operating conditions (i.e. after removal of the existing coils
and inlet silencer) and at 95,000 cfm flow are as follows:

Prefilters(@565 fpm)        : 0.32" WG (From manufacturers' data sheets)

Secondary filters (@565 fpm): 0.43" WG (From manufacturers' data sheets)        

Cooling Coil(@565 fpm)      : 0.35" WG (From manufacturers' data sheets)

Inlet Silencer              : 0.35

Outlet Silencer             : 0.15

90 Degree Turn Elbow        : 0.10 (Given by Motorola)

Plenum Losses               : 0.10 (Given by Motorola)

Room Losses                 : 0.05 (Given by Motorola)

Duct Losses                 : 0.05 (Given by Motorola)

Hepa Filter                 : 0.30 (Given by Motorola)



System Static Pressure  : 2.20" WG



Fan's duct velocity pressure: 1.20" WG



Total Pressure = S.P. + V.P. - Regain(*)

               = 2.20 + 1.20 - 0.75 = 2.65" WG



Efficiency: 79% (at Fan S.P. of 2.20 - 0.75 = 1.45" WG)


BHP = (95,000 x 2.65)/(6,360 x 0.79) = 50.1 HP