natural selection - Emerson

for its unique characteristics. In light of current environmental regulations, the popularity of these systems has increased significantly in North. America in recent ...
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NATURAL SELECTION Refrigeration systems continue to evolve toward natural refrigerants


he food retail, foodservice and industrial cooling industries

name R-744) are three naturally occurring refrigerants that pose

are in the midst of a momentous transition in their

very little threat to the environment.

refrigeration system architectures. In an era driven by

The emergence of natural refrigerants must be looked at

historic regulatory activity and the necessity to deploy sustainable

from a historical perspective, because in many ways it is a re-

systems, the number of refrigeration options available to these

emergence. In the 1980s, scientists discovered that CFC usage

operators seems to be growing exponentially — and with that,

was causing a hole in the ozone layer. An international treaty

an equal amount of confusion about what is the best future-

was quickly formed called the Montreal Protocol, which aimed

proof system alternative. To get to what many call the “end

to phase out the use of these substances. However, in recent

game” of achieving compliance and meeting corporate sustain-

years, the HFCs that succeeded CFCs were found to be a signifi-

ability objectives, more businesses are looking at systems based

cant source of global warming. As a result, the environmental

on natural refrigerants to help them achieve these goals.

impacts of refrigerants are measured by two key factors: global

The term “natural refrigerant” refers to substances that

warming potential (GWP) and ozone depletion potential (ODP).

naturally occur in the environment. Unlike the synthetic refrigerants

While new synthetic refrigerants are being developed that

that have commonly been used in refrigeration applications —

offer lower GWP and no threat to the ozone layer, many of these

including hydrofluorocarbons (HFCs) and chlorofluorocarbons

are either largely untested or yet to be deemed as acceptable

(CFCs) — ammonia (NH3 or refrigerant name R-717), propane

substitutes by global environmental regulations, such as those

(refrigerant name R-290) and carbon dioxide (CO2 or refrigerant

set forth by the U.S. Environmental Protection Agency (EPA).

K now Your Naturals AMMONIA



Ammonia was among the first refriger-

Propane is a hydrocarbon that was

CO2 is non-toxic and has proved to be

ants used in refrigeration applications.

also identified in the early days of

a very effective alternative to HFCs in

While its superior thermodynamic

refrigeration as an effective refrig-

both low- and medium-temperature

properties made it a logical first choice

erant. Its high-capacity, energy-

applications. CO2-based refrigeration

for early refrigeration systems, its toxic-

efficient performance and very low

systems have been successfully

ity requires the careful adherence to

GWP are offset by its classification as

deployed in commercial and industrial

safe application procedures to ensure

an A3 (highly flammable) substance.

applications in Europe for nearly two

operator and customer well-being.

But as synthetic refrigerants became

decades. Because of its low critical

With the advent of CFC refrigerants

available for many refrigeration

point and high operating pressure

in the mid-twentieth century, the