Trane AquaStream2 CXAN 490 - Minimum Water Loop Volume for Comfort Application

Table 8 - Minimum water loop volume for comfort application
CGAN CGAN CGAN CGAN CGAN CGAN CGAN CGAN CGAN CGAN CGAN CGAN
CXAN CXAN CXAN CXAN CXAN CXAN CXAN CXAN CXAN CXAN CXAN CXAN
200 250 300 400 450 490 500 600 700 800 900 925
Water volume (l) 250 360 360 610 640 620 370 370 500 650 760 630
At Eurovent conditions
CG-SVX01C-E4 19
Installation
Minimum water volume for a
process application or for a chiller
which has to run with low ambient
temperature option.
For Process application we have to
minimize the water temperature
fluctuation at part load. In order to
avoid problem on a scroll or a
hermetic reciprocating compressor it
must run at least 2 minutes
(120 seconds) before it stops and the
minimum time between two starts is
5 minutes (300 seconds).
The water volume has to be able to
provide the cooling capacity while
the unit is shut down.
The minimum volume can be
determined by using the following
formula
Volume = Cooling capacity x Time x
highest capacity step (%) / Specific
heat / Dead band
With these values the formula
becomes
Volume = Cooling capacity X 9.56 x
highest capacity step (%)
For the CGAN running in following
conditions: Air temperature 35°C,
water 12/7°C, this gives the following
volumes. If the total water volume of
the installation is below the above
mentioned values it is necessary to
use a buffer tank.
Minimum time = 180 seconds
(300-120)
Specific heat =4.18 kJ / kg
Dead band recommended =
Function of the process
With these values the formula
becomes:
Volume = Cooling capacity x 43 x
highest capacity step (%) / Dead
band
Increasing the dead band is like
adding water volume to the loop.