Cooling Water Requirements - Atlas Copco GA 37+ Instruction Book

4.6

Cooling water requirements

General
No general recommendation can encompass the effects of all combinations of the various
compounds, solids and gases typically found in cooling water in interaction with different materials.
Therefore the recommendations formulated in our Cooling Water Specifications are a general guide
line for acceptable coolant quality. However, where strict limits apply, a statement is made in the
specification.
The water requirements refer to untreated water. When water is treated, some parameters will
change. Water treatments should be carried out by a specialized water treatment company, taking
the responsibility for the performance of the treated cooling water and the compatibility with the
materials in the cooling circuit. This includes not only the selection of the appropriate additives, but
also the correct application, monitoring of concentrations and properties, prevention of sludge
formation and maintenance of the system. This applies also to treatment with antifreeze products.
They must be provided with suitable stabilizers and inhibitors. Specifications are also depending on
the type of cooling circuit (open, once through / recirculating with tower / closed) and on the
application (Standard – max 65 °C cooling water temperature at the outlet) or Energy Recovery
(water temperature up to 95 °C).
In case water is not in line with recommended values or if any doubt, consult the manufacturer.
Cooling water parameters
1. pH
The effect of pH is already included in the Ryznar Stability Index (RSI - see item 4 below), but
also the pH itself is subject to limitations:
Type of cooling system Materials
Single pass
Recirculating (with
tower)
58
Cooling water needs to fulfill certain requirements in order to avoid problems of
scaling, fouling, corrosion or bacterial growth.
In open circuit cooling towers, protective measures must be taken to avoid the
growth of harmful bacteria such as legionella pneumophila when there is a risk
of inhalation of the water droplets.
Containing copper
Stainless steel with
carbon steel and / or
cast iron
Stainless steel only
Containing copper
Stainless steel with
carbon steel and / or
cast iron
Stainless steel only
pH
Standard
6.8 - 9.3
6.8 - 9.3
6 - 9.3
6.8 - 9.3
6.8 - 9.3
6 - 9.3
Instruction book
Energy recovery
6.8 - 9.3
6.8 - 9.3
6 - 9.3
not applicable
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