4
V. Principles of Operation
If ambient air cannot be utilized directly as a cooling medium, another cost-effective method of cooling is
a Water-to-Air system (below). Water is used to remove heat from the air circulated within the electronics
enclosure.
Cooling water is circulated through a tube-and-fin coil. As the heat-laden air circulates through the coil, the
heat is absorbed by the water and carried away, in a continuous process.
Water-to-Air systems are easy to install and usually require minimum maintenance. The water used must be
reasonably clean and cold enough to ensure proper operation of the cooling system under the most
severe anticipated conditions. In some cases, if sufficiently cold water is available, below-ambient-
temperature cooling can be achieved.
The Heat Exchanger with options -- Automatic Water Flow Control is shown on Figure 2.
Heated Air
Blower
Water
with
Heat Load
Cold
Water
Heat
Exchanger
Cabinet
Cooled Air
WATER-TO-AIR
A Water-to-Air Heat Exchanger works by transferring heat of internal
air to circulating water, resulting in chilled air which is recirculated
throughout the electronics or electrical cabinet.
Blower
Water Control
Thermostat
Solenoid Valve
Water Control
Regulator
Figure 2
Figure 1
The Adjustable Water Control Thermostat opens and closes a water solenoid
valve based on the set point and differential settings. A temperature sensor is
located in the airstream of the cabinet. The Adjustable Water Control
Thermostat has a factory set point of 75
°
F.
