ClimaCool UGW Manual - Manual (Page 18)

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16
Chilled Water Temperature
Modules are designed for a leaving water temperature
range from 40°F to 62°F . All cataloged modules can operate
safely in this range without the need of special controls or
glycol additives . Leaving water temperatures below 40°F
can result in evaporator suction temperatures below the
freezing point of water . Therefore, a glycol solution additive
is required that will protect the evaporator from freeze ups
at lower operating suction temperatures . The full range of
leaving chiller fluid using glycol is 20°F to 62°F.
Water Temperature Requirements
Condenser Water Temperature
The condensers are designed to operate most efficiently
at lower entering water temperatures for lower power
consumption . The expansion valve, however, relies on
the pressure difference across the valve to drive the liquid
refrigerant through . It is necessary to maintain a minimum
pressure differential across the thermal expansion valve
(equivalent to a 30°F difference between saturated
liquid temperature in the condenser and saturated vapor
temperature in the evaporator) to avoid loss of efficiency
and system performance. This pressure differential is most
commonly ensured by cycling the fans on the cooling tower
to maintain the entering condenser water temperature
above the minimum temperature of 60°F . An alternate
method to maintain the minimum entering condenser water
temperature above 60°F is to employ a bypass arrangement
as shown in Figure 13 below . This valve is an automatic
3-way bypass valve, which senses the temperature of the
mixed water entering the condenser . If this mixed water
temperature falls below 60°F the valve will re-circulate
the leaving condenser water and mix it into the entering
condenser water stream (bypassing the cooling tower).
The full range of entering condenser water is 60°F to 95°F
for standard applications and maximum leaving hot water
temperature of 135°F for high temperature applications .
For entering water less than 60°F refer to Options and
Accessories (page 52) - Motorized Water Isolation Valves.
Note: Contact factory for applications outside of the
standard temperature range.
Figure 13 – Condenser Water System
Pressure Taps
Thermometer
Wells
Isolation Valves
Condenser Water
Flow Sensor or
Switch
Pressure Relief Valve
Flow to Tower Load
Flow from Tower
Cooling Tower
Bypass Valve
Strainer Isolation
Valve
Pump
Backflow
Preventer
Strainer
Drain
Valve
Backflow
Preventer
Pressure
Relief Valve
Note: Only required for equipment without motorized condenser valves .