chemicals may be put into the condenser return piping. If a cooling tower
bypass is included in the system design, the bypass should discharge into the
cooling tower basin(s) rather than into the cooling tower outlet piping.
2.12.3 CENTRAL CHILLED WATER PLANT FLOW DIAGRAM
Notes:
(a) The above arrangement shall be used for chilled water systems that
require two chillers to meet the cooling load. The chillers shall be air or
water-cooled.
(b) Primary chilled water pumps P-1 and P-2 shall be sized for the pressure
drop (PD) of the chiller and related piping.
(c) Secondary chilled water pumps P-3 and P-4, 50 percent capacity each,
shall be of variable flow type.
(d) Variable flow controller (VFC shall be used for 7.5 HP and larger pumps.
It shall measure the flow and provide a signal to start/stop primary pumps
according to predetermined flow set-point ranges.
(e) Differential pressure control (∆P) shall vary the speed of Pumps P-3 and
P-4.
(f) Other pumping systems may be considered but must be submitted to VA for
approval.
HVAC DESIGN MANUAL
2-41
HVAC SYSTEMS AND EQUIPMENT
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