7.
AHU / DX COIL Design
7-1. Equipment selection procedure -Selection flow chart-
1 Determination of air-conditioning load at each room.
2 Preliminary selection of AHU/FAHUs in the standard capacity no less
than air-conditioning load at each room.
3 Calculate corrected capacity A of each AHU/FAHU by correcting of
indoor temperature for the standard capacity of each AHU/FAHU.
(Refer to Chart [1])
4 Preliminary selection of outdoor unit in the standard capacity no less
than total valuese of corrected capacity A in AHU/FAHU. At same
time, check both connectable AHU/FAHUs number and the outdoor
diversity (Connected ratio of AHU/FAHU to outdoor units) for the
specificaitons.
5 Calculate corrected capacity B of each AHU/FAHU by following
2 Steps.
Step 1: Find the correction value of "Connecting pipe length and lift"
by both the longest length and the largest height with selected piping
condition at 4 or 4'. (Refer to Databook of Outdoor unit)
6 Corrected capacity B of
AHU/FAHU >= air-conditioning
load (for All rooms)
7 Find correction values of below items for the standard capacity of
outdoor unit selected at 4 or 4'.
Then determination of total corrected capacity of the selected
outdoor unit by all multiplying.
- Correction of indoor temperature condition (Refer to Chart [1])
- Correction of outdoor temperature condition (Refer to Databook of
Outdoor unit)
- Correction of connecting pipe length and lift between AHU/FAHU
and Outdoor units by both the longest length and the largest height
(Refer to Databook of Outdoor unit)
- Correction of outdoor unit diversity in only over 100% (Refer to
Databook of Outdoor unit)
- Correction of frost condition on outdoor heat exchanger when in
heating (Refer to Databook of Outdoor unit)
8 Calculate corrected capacity C of each indoor unit by multiplying the
total corrected capacity of outdoor unit at 7 by proportional division
of each indoor unit standard capacity for total standard capacity of all
indoor units.
9 Corrected capacity C of
AHU/FAHU >= air-conditioning
load (for All rooms)
YES
YES
END
– 24 –
2' Increase of AHU/FAHU capactiy
at object room against
air conditioning load.
NO
4 4 ' <Only cooling>
The correction characteristic of
"Connecting pipe length and Lift"
NO
(Refer to Databook of Outdoor unit)
between increased outdoor unit
at 4' and preliminary selected
outdoor unit at 4 is different.
(The both graphs are different.)
5 ' Increase of outdoor unit capactiy.
5
At the same time, check both
connectable AHU/FAHUs number
and the outdoor unit diversity.
YES