2.
INTRODUCTION
NATURAL REFRIGERANTS
DESIRABLE PROPERTIES
WHAT IS ODP AND GDP?
ODP and GWP of DIFFERENT REFRIGERANTS
APPLICATIONS
CONCLUSION
REFRENCES
TABLE OF CONTENTS
3.
Natural refrigerants:
Natural refrigerants are substances that serve as
refrigerants in refrigeration systems.
They are alternatives to synthetic refrigerants such as
CFC, HCFC, and HFC based refrigerants. Natural refrigerants
are non-synthetic and can be found in nature.
The most prominent of these include various natural
hydrocarbons, carbon dioxide, ammonia, and water.
Natural refrigerants are preferred to their synthetic
counterparts for their higher degrees of sustainability. With the
current technologies available, almost 75 percent of the
refrigeration and air conditioning sector has the potential to be
converted to natural refrigerants.
INTRODUCTION
4.
The natural refrigerants such as carbon dioxide,
ammonia and hydrocarbons (R290, R600, and R600a)
are among those refrigerants that are considered as
long time replacements for CFCs.
Water : Water(R-718) is the best known refrigerant
and its ease of availability makes it very popular.
The other important aspects of water are low cost
and safety.
NATURAL REFRIGERANTS
5. Carbon Dioxide : Carbon dioxide (R744) is a non-flammable,
non-toxic, odourless, inexpensive working fluid with zero
ODP and zero effective GWP. It can be obtained as a waste
product from different processes.
Ammonia : Ammonia (R717) has excellent thermodynamic
properties as compared to halo carbons. Ammonia has Ozone
Depletion Potential (ODP) and GWP equal to zero.
Hydrocarbons : In nature, hydrocarbon refrigerants are
constituents of oil and natural gas. Hydrocarbon refrigerants
have excellent environmental, thermodynamic, and thermo-
physical properties, however they are highly flammable.
The hydrocarbons most commonly used as refrigerants are:
Methane R-50, Ethane R-170, Propane R-290,
Butane R-600 , Isobutane R-600a, Ethylene R-1150,
Propylene R-1270.
6.
The refrigerants should have low boiling point and low
freezing point.
The refrigerants should be selected mainly for its high latent
heat of vaporization.
They must be harmless: non-toxic, non-flammable, non-
explosive and non-corrosive.
The pressures of the refrigerants, should allow their use in a
refrigeration system with areasonable size of the pipes and
compressor.
They must have high miscibility with lubricating oil.
They should give high COP in the working temperature range.
Finally, the most important criteria in the present day world is
that the refrigerant should havezero ozone layer depletion
potential and very low global warming potential.
DESIRABLE PROPERTIES
7.
ODP (Ozone Depletion Potential): index that shows
the damage that a substance may cause to the ozone
layer. ODP varies from 0 to 1 and the closer to zero,
the lower the impact on the ozone layer.
GWP (Global Warming Potential): a measure that
shows how much a given mass of greenhouse gas
contributes to global warming. CO2 is the reference
gas for the calculation, and its GWP is 1 by default.
The higher the GWP, the greater the impact on
global warming.
WHAT IS ODP & GDP
8.
Classification Refrigerant
Ozone Depletion
Potential
Global Warming
Potential
CFC
R-12 1 10,900
R-502 0.33 4,657
HCFC
R-22 0.055 1,810
R-123 0.06 77
HFC
R-23 0 14,800
R-32 0 675
Natural
R-170 (Ethane) 0 6
R-744 (Carbon
Dioxide)
0 1
R-717 (Ammonia) 0 0
R-718 (Water) 0 0
ODP and GWP of Select Synthetic and Natural
Refrigerants
ODP and GWP of Select Synthetic and Natural Refrigerants[13]
9.
In the aftermath of the Montreal protocole HFC’s
have predominantly replaced CFC’s and HCFC’s in
RAC equipment.
Due to high GWP, HFC’s are not a good replacement
solution.
The solution are the natural refrigerants:Ammonia ,
Hydrocarbons and Carbon dioxide.
Natural refrigerants can effectively reduce the
carbon footprint from refrigeration.
CONCLUSION
