how to size the FFU

通常有几种方法去算出FFU
1) Base on the room volume and A/C:
Room Vol ×__________A/C=______________CMH (recirculation air )

Recirculation air = _____________nos of the FFU
2330 (1200*1200ceiling type)
OR

Recirculation air = _____________nos of the FFU
1165 (1200*600, ceiling type)

2) Base on the total ceiling area and coverage :

Total ceiling area (M²) = _______________Nos of ceiling board
1.2×1.2(M²)
Coverage for FFU :

Class 1-----------------------------100%
Class10----------------------------50%
Class100--------------------------34%
Class100(test area)------------25%
Class1000-------------------------17%
Class10000-----------------------8%
Class100000---------------------5%

Nos of ceiling board × FFU coverage (%)= Nos of FFU

3) Base on the machine heat load :


V= Q_____________ = ______________________KW = _______________m³/s=________________________CMH
c×p×∆T 1.2×1.006×∆T( - )

• ∆T : on/off coil temperature
• Q: heat load from machine
• CMH: recirculation air
Recirculation air = _____________nos of the FFU
2330 (1200*1200ceiling type)
OR

Recirculation air = _____________nos of the FFU
1165 (1200*600, ceiling type)