October 2012
6-5
Operation, Maintenance, and User Education
As a first step, identify all equipment using single-pass cooling and follow these tips
to minimize or eliminate this water use:
••
Use the minimum flow rate required to cool the system recommended by the
manufacturer.
••
Install solenoid valves that shut off single-pass cooling water when the equip-
ment is turned off.
••
Regularly check operation of the water control valve so that cooling water only
flows when there is a heat load that needs to be removed.
••
Keep coil loops clean to maximize heat exchange.
••
If single-pass cooling cannot be eliminated, consult the
Section 8: Onsite Alterna-
tive Water Sources
to identify methods of reusing single-pass cooling water in
other applications.
Retrofit Options
For maximum savings, eliminate single-pass cooling by modifying equipment to
recirculate cooling water. This can be achieved by installing a closed-loop recircula-
tion system that will reuse cooling water instead of discharging it. A dedicated air-
cooled, point-of-use chiller can be added to most cooling systems to reject heat and
allow the cooling water to be reused. Alternatively, at some facilities, the single-pass
cooling water can be replaced with water from an existing recirculating chilled water
loop or cooling tower water loop, which are mechanical systems used to remove heat
from the water.
If single-pass cooling water cannot be eliminated through cooling water recircula-
tion, consider installing an automatic control that stops cooling water flow when
the equipment is not in use or no heat load is present. This retrofit will not entirely
eliminate water use, but it will minimize unnecessary water use.
Replacement Options
When possible, replace single-pass, water-cooled equipment with air-cooled
equipment. Air-cooled equipment uses no water for cooling purposes. If considering
air-cooled equipment as a replacement, evaluate the potential energy use of the
equipment in addition to the water use to ensure that the cost benefit from water
savings is not offset by an increase in energy use.
For detailed replacement options for specific equipment using single-pass cooling,
refer to the
WaterSense at Work
sections covering vacuum pumps, X-ray equipment,
ice machines, and wok stoves.
6.2
Single-Pass Cooling
