06-06
5. COOLING SYSTEMS:
5.1 GENERAL
A dedicated chilled water system shall be provided to serve the animal
research areas. This system shall be cross connected to the central
chilled water plant (if the medical center has any existing central
chilled water system) as an emergency back-up. The dedicated system
for the animal research areas shall operate as the primary source of
cooling.
5.2 SYSTEMS FEATURES
A. CHILLER(S) TYPE AND QUANTITY:
As far as possible, the chillers shall
be air cooled to facilitate easy start-up.
Two chillers of identical
capacity (50% each) shall be provided to meet the total cooling load
at design conditions. If the central chilled water plant is used as a
back up, for a small animal research project (178 KW (50 tons
capacity), a single chiller with multiple compressors can be used in
lieu of two separate chillers.
B. CHILLED WATER TEMPERATURE: The chillers shall be selected at low
leaving chilled water temperature (5oC)(42oF) to maintain the inside
C. PIPING/PUMPING ARRANGEMENT:
1. General: The piping/pumping arrangement shall be such that, during
part load conditions, when a chiller is not in use, its
auxiliaries can be shut down. To meet this need with multiple
chillers, primary/secondary pumping arrangement, as shown in
Supplement, Attachment No. 2, shall be used. According to this
arrangement, each chiller shall have its own primary chilled water
pump. With two chillers, three primary chilled water pumps shall
be provided; the third primary chilled water pump shall act as 50%
standby. Similarly, with water cooled chillers, each chiller shall
have its own condenser water pump. With two chillers, three
condenser water pumps shall be provided; the third pump shall act
as 50% standby.
2. Secondary Chilled Water Piping: In Supplement, Attachment No. 3,
suggested secondary interface is shown with variable flow, two way
chilled water control valves, and variable speed secondary pumps.
For a small project with only one air handling unit, constant flow
primary chilled water pump can be used to circulate water through
the chilled water cooling coil as well. With this arrangement, the
cooling coil shall be equipped with a three way control valve.
3. Tertiary Chilled Water Piping: In Supplement, Attachment No. 4,
suggested secondary/tertiary chilled water interface is shown.
This arrangement shall be used when the animal research areas are
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