No, it is not "absolutely" necessary to use softened water in a cooling tower. What is fairly necessary is to consult a well-known water treating company and ask their advice based on your raw water composition as to:
(1) The number of concentration cycles to used in the system
(2) The proper water treating chemicals and the proper amounts of those chemicals to be used for scale control, anti-fungus control, pH control, etc.
The Nalco company and the GE Betz company are two of the well-known experts in this field.
Milton Beychok
(Visit me at www.air-dispersion.com)
.
olmedo,
The cleaner the water you are using, the longer you can circulate it in your coling tower. The dirtier, more of it has to be blown-down to be acceptable for a particular cooling tower you purchased, more make-up has to be pumped in the system, to not mention the hasless of disposing off the contaminated water. Also, the local chemicals you have to use will cost you more. In other words, you trade the less treated water for additional costs related to the use of untreated water. Obviously, you are the only one to judge it to suit your budget and the plant circumstances. You should consult the cooling tower fabricator for his recommandations also.
gr2vessels
In most cases, completely softened water will cause corrosion in condenser, basin and cooling tower/exchanger.
Depending from raw water composition and treatment program, you can operate up to Ca levels of 1100mg/l as CaCO3 (i.e Palo Verde circulating water analysis).
Two listed in previous post companies should give you good answers what you can do with your water.
