Hey, Rick Uzubell again from Cabaret Design Group,
talking today about long-draw draft beer
system design.
Today we're going to talk
glycol draft beer system design. What are
the fundamental components of glycol
draft beer systems? This process is
accomplished through three components:
the power pack, the trunk line and the beer
tower. I'm going to show you these ideas
here in a bar plan of a system that we're
currently designing. The power pack, which
is a commercial refrigeration unit, is
the heart of the glycol system. The power
pack is rather compact, as seen in this
photo. But don't let this small package
fool you. An individual power pack can
have from one to three motors and pumps.
The end-result is that a single, properly-sized
power pack can manage up to three
trunk lines, each up to 750 feet in
length and each capable of handling up
to 24 beer products. In this plan, we're showing
the possibilities for three
different opportunities for trunk lines
in this particular building. A typical
trunk line is shown in this photo: here
you'll see the cross-section of a
typical eight-product draft beer trunk line.
You'll notice a total of eight narrow-diameter
product lines around the
perimeter, sandwiched around a pair of
glycol refrigeration lines. One glycol line
is outbound, extending from the power pack
to the beer tower and the other returns
from the beer tower back to the power
pack. Each product line of the trunk line
is connected to a unique barrel of beer
in the walk-in cooler and each barrel of
beer is connected to CO2 and nitrogen
cylinders through a series of gas
blenders and pressure regulators, as
shown here in this photo. A more simplistic
explanation is that the trunk line
provides a conduit of beer product lines
connecting barrels of beer in the
walk-in cooler to each respective faucet
of the draft beer tower, while also
housing sealed refrigeration lines from
the power pack to the tower in a
continuous loop. The assembly of product
lines and glycol lines is wrapped in a
shield of foam and encased in a plastic
waterproof jacket, as we just saw a
moment ago, and it looks like this. The
waterproof jacket is
fairly flexible and fairly easy to
manipulate. How are glycol draft beer lines
installed? Trunk lines are typically
installed overhead or under-floor. If
installed overhead, the exposed downward
trunk lines would generally be housed in
a combination of PVC tubing and a
decorative finish. Heavy pipe is
another popular approach as shown in
this photo. When installing under
concrete, you would run these product
lines through a section of PVC tubing.
This particular line that we're showing
here, which is eight products, is two-and-
three-quarters inches in diameter and
would typically be installed inside a
six-inch schedule 40 PVC conduit. How do
glycol beer systems work? The way the
system works is that the power pack
pushes refrigeration through the center
of the trunk line. The trunk line contains
an outbound glycol line which runs from
the power pack to the tower, over here, and
return glycol line, which enables the
refrigerant to complete the cycle and
become re-chilled. The job of the
refrigerant lines is to keep all of the
surrounding beer lines temperature-controlled
from the point of origin to
the point where they're dispensed. The
fundamental challenge of glycol draft
beer systems is to transport the beer
from the walk-in cooler, over here, whose
temperature is 36 to 38 degrees
Fahrenheit, over significant distance, and
dispense the beer over here at this
tower at 36-38 degrees Fahrenheit.
This is mandated by the brewers and has
been deemed to be the ideal temperature
range for draft beer to maintain its
intended characteristics. Now, as the beer
travels along its journey, it tends to
increase in temperature due to the gas
that's pushing it and the resulting drag
of the plastic product lines that
resist. Therefore, heat accumulates inside
the product lines. The beauty of the
glycol system is that the refrigerant
lines, through the
principles of thermodynamics, dissipate
the temperature gains of the product
lines as they get warmer. So, the idea is,
even though the refrigerant and the
glycol line is between 29 to 32 degrees
Fahrenheit, it's there by design --
it's there because it will ultimately
offset the rising temperature of the
surrounding product lines, so as to
deliver the beer products at the
recommended temperature by the time they
get to each respective faucet. Once the beer
product approaches the tower, however, the
job still isn't over, because the beer
can still experience temperature gain
over the last segment of its journey. In
other words, a lot could still go awry
inside the beer tower. Therefore, a bit of
additional engineering is designed into the
tower in order to complete the mission
of delivering cold beer right up to the
end of each faucet. The way this is
achieved is that each of the beer faucets
inside the tower, shown right here in
these black circles, has a stainless
steel shank that extends inside the
tower head. A copper assembly known as
the "cold block," as shown here in this
eight-faucet Micro-Matic Metro T glycol
tower (and here's a side view) -- provides the rest
of the magic.
The inbound glycol refrigerant line,
shown here in blue, enters the beer tower
through a copper line that travels
vertically inside the tower and creates
a complete loop for the refrigerant to
return to the power pack. So it travels
around a large loop and returns back to
the power pack. Along its path, however, a critical
engineering detail is completed. Along
the return path of the glycol refrigerant,
its copper loop contacts the shank of
each faucet and also branches into each
respective faucet. This branch is known
as the "cold block." The end-result is that
the temperature of each beer product is
controlled all the way to the point of
dispensing. Upon leaving the tower, the
return-side of the glycol loop returns
to the power pack so the refrigeration
cycle can be repeated and repeated again.
Even on its way back to the power pack,
the return leg of the glycol line still
helps to stabilize the temperature of
the beer products on their way to the
tower. This is the engineering of how
glycol draft beer systems work.