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Step 2 - Fill Coolant Circuit
Check to make sure all process chilled-water piping
connections are secure. Fill the chilled water
reservoir with the proper water or water/glycol
solution following the guidelines shown below.
When using a glycol solution only use glycol with a
corrosion inhibitor. See Table 34 for recommended
glycol solutions.
System Fill Water Chemistry Requirements
Water is a unique molecule whose properties make it
ideal for heat transfer applications. It is safe: non-
flammable and non-poisonous. It is easy to handle,
widely available and inexpensive in most
industrialized areas. It is capable of absorbing more
heat per unit mass than almost any other material.
Water also has properties that need to be within
limits to avoid unwanted side effects. Water is a
“universal solvent” because it can dissolve many
solid substances to some extent and absorb gases.
As a result, water can cause the corrosion of metals
used in a cooling system. Often water is in an open
system (exposed to air) that concentrates the ions as
water evaporates as in a cooling tower. When the
concentration exceeds the solubility of some
minerals, scale forms. The life giving properties of
water can also encourage biological growth that can
foul heat transfer surfaces.
Sometimes the source of the water can be the cause
of some of the problems. Anyone living in an area
with extremely hard water that has caused scale
build up can attest to that. Source waters available
for make-up use have an almost unlimited chemistry
variation.
To avoid the unwanted side effects associated with
water cooling, proper chemical treatment and
preventive maintenance is required for continuous
plant productivity.
Unwanted Side Effects of Improper Water Quality
• Corrosion
• Scale
• Fouling
• Biological Contamination
Cooling Water Chemistry Properties
• Electrical Conductivity
• pH
• Alkalinity
• Total Hardness
• Dissolved gases
Some of the water chemistry properties can combine
to cause the unwanted side effects. Some of the
levels are temperature dependent (i.e. dissolved
gases).
Our chiller construction minimizes the potential for
corrosion by using stainless steel brazed plate
evaporators. The stainless steel resists corrosion but
is not immune to it. All heat exchangers are
susceptible to fouling that may coat the heat transfer
surfaces. Coating of these surfaces reduces the heat
transfer surface, increases the fluid velocities and
pressure drops through the heat exchanger. All of
these effects reduce the heat transfer and affect the
productivity of the plant. This is just as true with shell
and tube heat exchangers.
Chilled cooling water systems, at their simplest, have
two main heat exchangers: the evaporator that
absorbs the heat from the process and the
condenser that removes the heat from the chiller.
The chiller is only part of the entire cooling system.
The system requires proper design following sound
engineering practice and satisfying local and
industry standards. Improperly designed or installed
systems may cause unsatisfactory operation and/or
system failure.
The complex nature of water chemistry requires a
specialist to evaluate and implement appropriate
sensing, measurement and treatment needed for
satisfactory performance and life. The
recommendations of the specialist may include
filtration, monitoring, treatment and control devices.
With the ever-changing regulations on water usage
and treatment chemicals, the information is usually
up to date when a specialist in the industry is
involved. Table 33 – Fill Water Chemistry
Requirements shows the list of water characteristics
and quality limitations.
