40
In evaporative cooling, evaporation of a small portion of the recirculating spray water
as it flows through the equipment causes the cooling effect. As this water evaporates,
the impurities originally present remain in the recirculating water. The concentration of
the dissolved solids increases over time and can reach unacceptable levels. In addition,
airborne impurities are often introduced into the recirculating water. If these impurities
and contaminants are not effectively controlled, they can result in scaling, corrosion, and
sludge accumulations that reduce heat transfer efficiency and increase system operating
costs, while potentially shortening the useful life of the equipment. The degree to which
dissolved solids and other impurities build up in the recirculating water may be defined
as the cycles of concentration. Specifically, cycles of concentration equals the ratio
of the concentration of dissolved solids (for example - chlorides, sulfates, etc.) in the
recirculating water to the concentration of the same material in the incoming make-up
water.
• In order to optimize heat transfer efficiency and maximize equipment life, a small
amount of recirculating water must be bled from the system. This controls the cycles
of concentration to maintain the quality of the recirculating water within the guidelines
given in
Table 3
, on
page 31
.
• The included conductivity controlled blowdown system consists of a conductivity
sensor and a drain valve. Refer to
page 28
for conductivity sensor cleaning
instructions. The iPilot
®
Control System will open the motorized drain valve whenever
the conductivity meter reading exceeds the conductivity setting. This value has been
factory set for the specific materials of construction of the unit, but can be adjusted
under the direction of a competent water treatment specialist based on specific site
conditions and make-up water quality to help minimize water usage.
• The Nexus
®
Cooler will automatically replenish the bleed water with fresh make-up
water, thereby limiting the build-up of impurities.
The following example provides more details about the bleed rate.
NOTE:
A proper water treatment
program, administered under the
supervision of a competent water
treatment specialist, is an essential
part of routine maintenance
to ensure optimum thermal
performance, water conservation,
safe operation, and the longevity of
evaporative cooling equipment, as
well as other system components.
The Nexus
®
Modular Hybrid Cooler
offers features that facilitate
the time and effort required to
implement and operate a successful
water treatment program, including
a conductivity controlled blowdown,
low spray water basin volume, and
a high percentage of dry operation.
NOTE:
Although evaporation is
proportional to the load and will
vary seasonally, water can be
conserved by ensuring an optimal
bleed rate that protects the
equipment from excessive corrosion
and biological growth.
NEXUS
®
MODULAR HYBRID COOLER
Bleed Rate
5
Содержание NEXUS NXF-0403N-CS2TS-H1
Страница 1: ...OPERATION MAINTENANCE MANUAL...
