SECTION 4 - INSTALLATION
JOHNSON CONTROLS
41
Form 201.28-NM1.1
Issue date: 08/06/2021
4
Figure 10 -
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.
Thermal storage
Thermal storage is the practice of storing cooling
energy during a period of little or no load and/or low
energy costs for use during periods of high load and/
LD15051
Figure 11 -
Suggested Layout for Applications with a
Flow Rate Greater Than the Evaporator
Maximum Allowable Flow Rate
Bypass
Supply to load
Load
or energy costs. Conventional cooling systems pro-
duce cooling when it is needed which is commonly
during times of peak demand. Thermal storage allows
generation of cooling capacity to occur during off-
peak periods and store that capacity to meet future
cooling requirements. Using thermal storage can result
in smaller equipment sizes, thereby reducing capital
cost, and also can result in significant energy cost sav-
ings.
The YVAA has special control logic to be able to pro-
duce chilled leaving brine temperatures below 4.4°C
(40°F) so as to supply a storage tank with chilled liquid
during times of low demand. YVAA chillers selected
for thermal storage operation can also be selected to ef-
ficiently provide chilled fluid at nominal cooling loads.
Variable primary flow
Johnson Controls recommends a maximum 10% per min-
ute flow rate of change, based on design flow, for vari-
able primary flow applications. Provide 8 to 10 gallons
per chiller ton (8.6 to 10.8 liter per cooling KW) system
water volume. Insufficient system volume and rapid flow
changes can cause control problems or can even cause
chiller shutdowns. There are many other design issues
to evaluate with variable primary flow systems. Consult
your Johnson Controls Sales Office for more information
about successfully applying YVAA chillers.
Connection types and sizes
For connection sizes relevant to individual models see
.
Evaporator connections
Standard chilled liquid connections on evaporators are
of the grooved type for ASME and PED marked units
and Flange type for GB marked units (see
for flange dimensions on GB marked ves-
sels).
Figure 12 -
Grooved nozzle
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