TM
5-858-7
low-temperature waste heat could reduce heat-sink
and water chillers for part of the low-temperature
volume for the battery inverter and fuel cell-
cooling allow higher heat-sink temperatures, com-
inverter systems, but would have limited value for
pared to the temperatures required with direct
the other three systems under the conditions
cooling systems. Potential gains may be limited by
assumed.
the refrigeration system's power demand and the
additional waste heat produced. For a spread of
g. Since low-temperature waste heat usually
controls heat-sink requirements, raise the cooling-
water and the condenser cooling water, the power
system efficiency wherever possible by maximum
demand for refrigeration is about 20 percent of the
use of direct liquid cooling of equipment. In the
heat rejected, which increases the heat-sink re-
case of large-size equipment, it is generally a mat-
quirements by the same percentage. Larger tem-
ter of selecting liquid-cooled rather then air-cooled
perature spreads due to either low chilled-water
equipment. In the case of smaller equipment it may
temperature or higher condenser-water tempera-
mean specifying liquid cooling for small units
ture will reduce the refrigeration efficiency and
where air cooling has been customarily considered
increase the added power and waste-heat loads.
more cost effective. Consider liquid cooling for air
compressors, and receivers, vacuum pumps, refrig-
i. The use of refrigeration brines offers a techni-
eration compressors, and power transmission ele-
cally feasible and well-developed (although not nec-
essarily cost effective) method of developing lower
transmissions. Wherever possible, specify direct
initial heat-sink temperatures without using ice.
heat removal from refrigeration compressors by
Disadvantages are the requirements for increased
cooling-water or oil-to-water cooling systems, rath-
use of inhibitors to minimize the corrosive effect of
er than using the refrigerant to cool the compres-
brines, and for increased refrigeration costs to
sor. It may be possible to use liquid cooling, rather
maintain the heat sink at the lower temperatures
than traditional air cooling, for electrical genera-
feasible with brine. However, compared to fresh
tors, motors, and transformers; radio transmitter
tubes, tank coils, and tuning capacitors; power fac-
ride brine would extend the feasible initial heat-
tor correction capacitors; and high-power solid-
sink temperature down to about 15F and reduce
state device heat sinks.
the volume requirement by about 33 percent. Simi-
h. Mechanical refrigeration offers a potentially
larly, use of calcium chloride brine over the range
more effective approach to efficient heat-sink utili-
zation. Mechanically refrigerated dehumidifiers
about 66 percent.
3-5
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