York YVAA, Инструкция по установке, эксплуатации и обслуживанию, Страница: 42 / 178

JOHNSON CONTROLS
42
SECTION 4 - INSTALLATION
FORM 201.28-NM1.1
ISSUE DATE: 1/31/2018
MINIMUM WATER VOLUME
It is good practice to include as much water volume
as possible in a chilled water loop. This increases the
thermal mass and “Flywheel” effect within the system
(that is, the more; the better) which in turn promotes
stable water temperature control and increases reliabil-
ity by reducing compressor cycling.
For air conditioning applications, a minimum of 3
gallons/ton is required. with a preferred gallon/ton
ratio to be within the 5 to 8 range. For process applica-
tions, a minimum of 6 gallons/ton ratio is required with
preference towards a range of 7 to 11. Install a tank or
increase pipe sizes to provide sufficient water volume.
LEAVING WATER TEMPERATURE OUT OF
RANGE
The YVAA chiller line has a maximum leaving water
temperature of 15.6°C (60°F). Where process applica-
tions require a chilled water temperature higher than
what the chiller provides, a simple piping change can
remove the problem. By using a mixture of chiller-
cooled water and returning process water, the chilled
water entering the process can be held at the desired
temperature. A tank can also be used to meet high
leaving water temperature requirements.
Each YVAA evaporator has a minimum and maximum
flow rate. Some process applications require a flow
rate that is out of range for the evaporator. In those ap-
plications, a piping change can remove the problem.
FIGURE 8 - LEAVING WATER TEMPERATURE OUT
OF RANGE SUGGESTED LAYOUT
LD15049
RECIRCULATION
SUPPLY TO LOAD
RETURN FROM LOAD
LOAD
In applications where the required flow rate is less than
the evaporator’s minimum allowable, the chilled water
can be recirculated to the chiller.
FIGURE 9 - SUGGESTED LAYOUT FOR
APPLICATIONS WITH A FLOW RATE
LESS THAN THE EVAPORATOR
MINIMUM ALLOWABLE FLOW RATE
LD15049
LOAD
SUPPLY TO LOAD
BYPASS
RETURN FROM LOAD
In applications where the required flow rate is greater
than the evaporator’s maximum allowable, the chilled
water can be recirculated to the load.
LD15051
FIGURE 10 - SUGGESTED LAYOUT FOR
APPLICATIONS WITH A FLOW RATE
GREATER THAN THE EVAPORATOR
MAXIMUM ALLOWABLE FLOW RATE
BYPASS
SUPPLY TO LOAD
LOAD