Atlas Copco GA 11+ Instruction Book page 89

Instruction book
Heat exchanger (HE)
If the temperature rise over the energy recovery system declines over a period of time with the
same basic working conditions, the heat exchanger should be inspected. To clean the oil side,
soak the heat exchanger in a degreasing solution. To remove scale formation in the water
compartment, a proper descaling process should be applied. Consult your supplier.
6.1.5 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
Single pass
Recirculating (with tower)
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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.
Materials
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
Energy recovery
6.8 - 9.3
6.8 - 9.3
6 - 9.3
not applicable
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