Page 201 - WaterSense at Work

October 2012
Page 42.
Texas Water Development Board. November 2004.
Water Conservation Best Practices Guide
Page 148.
Using Appropriate Onsite AlternativeWater Sources
Use onsite alternative water sources where appropriate and feasible (see
Section 8:
Onsite Alternative Water Sources
for more information). Work with the water treat-
ment vendor to ensure that the alternative sources identified are a good match for
the cooling tower, considering the water chemistry of the source and water quality
needs of the cooling tower.
Reducing Biological Growth
Install covers to block sunlight penetration. Reducing the amount of sunlight on
tower surfaces can significantly reduce biological growth such as algae. Controlling
algae growth can help increase cycles of concentration and improve water quality in
the tower.
Replacement Options
Since replacing a cooling tower involves significant capital cost, facilities should first
implement all efficient operation and maintenance procedures and perform any
retrofits available to optimize the current cooling tower’s management scheme. After
exhausting all efficient management practices and considering the costs and ben-
efits of a new tower, new cooling tower designs and improved materials can provide
additional water and energy savings.
Savings Potential
Significant water savings can be achieved by improving the cooling tower manage-
ment approach. A key mechanism to reduce water use is to maximize the cycles of
concentration. Table 6-1 shows the percentage of make-up water savings that can
be expected by increasing a cooling tower’s cycles of concentration, denoted as the
concentration ratio (CR).
Figure 6-3 further illustrates this point by showing how in-
creasing cycles of concentration can decrease water use in a 100-ton cooling tower.
Each facility should determine the maximum cycles of concentration it can achieve
depending upon the quality of the make-up water supply and other facility-specific
Cooling Towers