System Configurations
SYS-APM001-EN
31
Primary secondary (decoupled) systems
The root cause of essentially all of the difficulties with parallel chiller control is
the fixed relationship between chiller and system flow rates. If, instead, we can
hydraulically decouple the production (chiller) piping from the distribution
(load) piping, it is possible to control them separately. The fixed relationships
are then broken apart.
System basics
Hydraulic decoupling
Figure 11 shows the basic decoupled system. This strategy is also referred to as
a primarysecondary pumping arrangement. Separate pumps are dedicated to
production and distribution. While the same water is pumped twice (by
different pumps), there is no duplication of pumping energy. This is because
the production pumps overcome only the chiller and production-side pressure
drop while the distribution pumps overcome only the distribution system
pressure drops.
Figure 11 Decoupled arrangement
Chiller 3
Chiller 2
Chiller 1
Bypass Line
Supply
Production
Distribution
Summary :
System Configurations SYS-APM001-EN 31 Primary secondary (decoupled) systems The root cause of essentially all of the difficulties with parallel chiller control is the fixed relationship between chiller and system flow rates.
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chiller,system,distribution,pumps,production,decoupled,oercome,while,pressure,figure,piping,only,fixed