EcoWater CHC Series, Service And Troubleshooting Manual, Page: 92 / 130

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Customer evaluation and training.
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Timely delivery of accurate reports.
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Timely shipment of water samples for analysis.
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Discuss Service Visit with the appropriate customer contact.
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Verify follow up with regards to notes and customer comments.
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Refine schedule as needed.
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Your EcoWater CHC Field Technician will be contacting the customer upon receipt of the submitted CSR in
Ulysses.
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Notify Carl Steffen via email SteffenC@ECOWATER.COM of any items that need to be addressed. Please use
the following phrase in the subject line of the email “SERVICE ACTION REQUESTED”
6.7 CYCLES OF CONCENTRATION
What are Cycles of Concentration ? Cycles are not the flow cycles of water in the system. It is a
comparison of the concentrations of dissolved salts in makeup water and basin water. Because of
evaporation, H
2
O left water to evaporate and leave the dissolved salts in cooling water. So the
concentration of the dissolved salts in the cooling tower water will increase. Cycles of 2 means the
concentration of certain species (like sodium or chlorides) in the cooling tower water are 2 times the
concentration in the makeup water.
How do you calculate cycles? The easy, and most popular method is to use TDS (Total Dissolved
Solids). Cycles are equal to the TDS (or conductivity) ratio of basin to makeup. This is based on the
assumption that all dissolved constituents in makeup will still be in basin water. The evaporation is the
only source for changes in concentration. This is true for systems with a successful chemical treatment.
But for water treated by CHC, parts of the dissolved calcium and bicarbonate are transformed into
calcium carbonate solids. TDS is only good for estimating the cycles, EcoWater CHC recommends the
use of chloride concentrations to calculate the actual cycles.
If the makeup and blow down rates are known, cycles can also be calculated by the ratio of makeup
volume to blow down volume. This method will give an average cycles over a certain time period,
instead of a snap shot value when using TDS or chloride.
TDS vs. cycles: When we tell customers we are going to reduce blow down significantly, the
customers may think there will be a huge bump up in cycles and TDS. Yes, cycles will go up, but not
necessarily TDS. Let's look at this in detail:
When using chemical treatment, acids or scale inhibitors are used to prevent the precipitation of
calcium carbonate, so all the dissolved solids from makeup will stay in the water. Therefore the TDS
of the cooling water is linearly proportional to the makeup TDS and cycles:
TDS (basin) = TDS (makeup) * cycles
Actually, the TDS (basin) may be even higher, because of the addition of treatment chemicals. This is
usually negligible; but for some water having very low TDS, such as water from the Pacific North
West, the contribution could be noticeable.
When water is treated by CHC, reactions in the CHC chamber will force some dissolved Calcium and