Enertech AV Series - Section 6: Antifreeze; Antifreeze Overview; Antifreeze Charging

Enertech Global, LLC 34
AV : MD/ME - Rev. A Models
Installaon and Operaons Manual

If the unit will be used for cooling, anfreeze must be added
on the load side of the system to protect the braze plate heat
exchanger from rupturing. Chilled soluon set points are in
the 40’s °F. The load soluon so within the heat exchanger,
could be near freezing. To protect against freezing. Enertech
recommends the use of Propylene Glycol (20-25%) for the
load side anfreeze. Addional inhibitor may be required if
the concentraon is less than 25% to 30% (depending upon
brand) to provide corrosion protecon and prevent bacterial
growth.
Important: Propylene glycol concentraons below 30%
typically require addional inhibitors to be added to the
soluon. Enertech recommends Fernox F1.
Note: The minimum recommended air handler size is 2 tons.

Selecon of the anfreeze soluon for closed loop systems
require the consideraon of many important factors, which
have long-term implicaons on the performance and life of
the equipment. Each area of concern leads to a dierent “best
choice” of anfreeze. There is no “perfect” anfreeze. Some
of the factors to consider are as follows (Brine = anfreeze
soluon including water):
Safety: The toxicity and ammability of the brine (especially
in a pure form).
Cost: Prices vary widely.
Thermal Performance: The heat transfer and viscosity eect
of the brine.
Corrosiveness: The brine must be compable with the
system materials.
Stability: Will the brine require periodic change out or
maintenance?
Convenience: Is the anfreeze available and easy to
transport and install?
Codes: Will the brine meet local and state/provincial codes?
The following are some general observaons about the types
of brines presently being used:
Methanol: 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, it is ammable
in concentraons greater than 25%.
Ethanol: Grain alcohol, which by the ATF (Alcohol, Tobacco,
Firearms) department of the U.S. government, is required to
be denatured and rendered unt 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 is also ammable
with concentraons 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
compable with HDPE pipe (for example, soluons denatured
with gasoline).
Propylene Glycol: Non-toxic, non-corrosive, mid to high price,
poor heat transfer in high concentraons, and potenal for
high viscosity when cold (in high concentraons). It has also
been known to form a “slime-type” coang 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
soluon is a minimum concentraon for required inhibitors,
depending upon brand of glycol. If using a lower concentraon
(e.g. 20% provides 19°F freeze protecon), addional
inhibitors must be added. Note that some states/provinces
have toxicity requirements that must be veried based upon
the chemical composion of the inhibitors.
Ethylene Glycol: Considered toxic and is not recommended for
use in earth loop applicaons.

Calculate the total amount of pipe in the system and use the
following Pipe Fluid Volume Table to calculate the amount of
volume for each specic secon of the system. Add the enre
volume together, and mulply that volume by the proper
anfreeze percentage needed 
 for the freeze protecon required in your area.
Then double check calculaons during installaon with the
proper hydrometer and specic gravity chart 
) to determine if the correct amount of
anfreeze was added.
⚠ WARNING ⚠
USE EXTREME CARE WHEN OPENING, POURING,
AND MIXING FLAMMABLE ANTIFREEZE SOLUTIONS.
REMOTE FLAMES OR ELECTRICAL SPARKS CAN IGNITE
UNDILUTED ANTIFREEZES AND VAPORS. USE ONLY
IN A WELL VENTILATED AREA. DO NOT SMOKE WHEN
HANDLING FLAMMABLE SOLUTIONS. FAILURE TO
OBSERVE SAFETY PRECAUTIONS MAY RESULT IN
FIRE, INJURY, OR DEATH. NEVER WORK WITH 100%
ALCOHOL SOLUTIONS.
Secon 6: Anfreeze
Pipe Fluid Volume Table
Type Size
Volume Per 100
US Gallons
Copper 1” CTS 4.1
Copper 1.25” CTS 6.4
Copper 1.5” CTS 9.2
HDPE .75” SDR11 3.0
HDPE 1” SDR11 4.7
HDPE 1.25” SDR11 7.5
HDPE 1.5” SDR11 9.8
HDPE 2” SDR11 15.4
Notes:
Unit coaxial heat exchanger = 1 Gallon
Flush Cart = 8-10 Gallons
10’ of 1” Rubber Hose = 0.4 Gallons
⚠ WARNING ⚠
IF MORE THAN 30% ANTIFREEZE IS ADDED, HEAT
TRANSFER AND VISCOSITY ISSUES MAY ARISE. BE
SURE TO KNOW WHAT TYPE OF ANTIFREEZE IS

⚠ CAUTION ⚠
HYDRONIC LOOPS MUST BE ANTIFREEZE PROTECTED.
INSUFFICIENT AMOUNTS OF ANTIFREEZE MAY CAUSE
SEVERE DAMAGE AND MAY VOID WARRANTY.

FLAMMABLE. NEVER OPERATE WITH HYDRONIC LOOP
FLOW RATES LESS THAN SPECIFIED. CONTINUOUS
OPERATION AT LOW FLOW OR NO FLOW MAY CAUSE
SEVERE DAMAGE AND MAY VOID WARRANTY.