Enertech Global
EAV - EME/EMD Rev. A Models
Installaon and Operaons Manual
Selecon of the anfreeze soluon for closed uid systems
require the consideraon of many important factors, which
have long-term implicaons on the performance and life of
the equipment. Each area of concern leads to a dierent “best
choice” of anfreeze. There is no “perfect” anfreeze. Some of
the factors to consider are as follows (Brine = anfreeze soluon
including water):
The toxicity and ammability of the brine (especially in a
pure form).
Prices vary widely.
The heat transfer and viscosity eect of
the brine.
The brine must be compable with the system
materials.
Will the brine require periodic change out or
maintenance?
Is the anfreeze available and easy to transport
and install?
Will the brine meet local and state/provincial codes?
The following are some general observaons about the types of
brines presently being used:
Wood grain alcohol that is considered toxic in pure
form. It has good heat transfer, low viscosity, is non-corrosive,
and is mid to low price. The biggest down side is that it is
ammable in concentraons greater than 25%.
Grain alcohol, which by the ATF (Alcohol, Tobacco,
Firearms) department of the U.S. government, is required to
be denatured and rendered unt to drink. It has good heat
transfer, mid to high price, is non-corrosive, non-toxic even in
its pure form, and has medium viscosity. It also is ammable
with concentraons greater than 25%. Note that the brand of
ethanol is very important. Make sure it has been formulated
for the geothermal industry. Some of the denaturants are not
compable with HDPE pipe (for example, soluons denatured
with gasoline).
Non-toxic, non-corrosive, mid to high price,
poor heat transfer in high concentraons, and potenal for high
viscosity when cold (in high concentraons). It has also been
known to form a “slime-type” coang inside the pipe when
inhibitors are not used. Do not use food grade glycol, since it
does not include inhibitors. A 25% to 30% brine soluon is a
minimum concentraon for required inhibitors, depending upon
brand of glycol. If using a lower concentraon (e.g. 20% provides
19°F freeze protecon), addional inhibitors must be added.
Note that some states/provinces have toxicity requirements that
must be veried based upon the chemical composion of the
inhibitors.
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