This presentation contains the properties of refigerants

1. REFRIGERANTS
AND
ITS PROPERTIES
Er.Krishna Kumar Yadav
M.Tech (IIT Kanpur)

2. INTRODUCTION
 Refrigerant : is the primary working fluid used for absorbing and
transmitting heat in a refrigeration system.
Refrigerants absorb heat at low pressure and low temperature and
release heat at a higher temperature and pressure
 Typically, refrigerants undergo phase-changes during heat absorption
(evaporation) and heat releasing (condensation)
Air used in an air-cycle refrigeration system can also be considered as a
refrigerant (no phase-change).

3. INTRODUCTION
The thermodynamic COP of a refrigeration system depends mainly on its
operating temperatures
However, important practical issues such as the system design, size, initial
and operating costs, safety, reliability, and serviceability etc. depend very
much on the type of refrigerant selected for a given application.
Due to several environmental issues such as ozone layer depletion, global
warming and their relation to the various refrigerants used, the selection
of suitable refrigerant has become one of the most important issues in
recent times.
Hence, it is very important to understand the issues related to the
selection and use of refrigerants

4. PROPERTIES OF REFRIGERANTS
Mechanical Properties Chemical Properties
a)Low boiling and freezing point
b)High critical pressure and
temperature
c)High latent heat of vaporisation
d)Low specific heat of liquid and High
specific heat of vapour
e)Low specific volume of Vapour
f) High Thermal conductivity
g)High COP
a)Non-corrosive to metal
b)Non-toxic
c)Non- flammable and non-
explosive
d)Oil Solubility
e)Low Water Solubility

5. PROPERTIES OF REFRIGERANTS
Environmental Effects of
Refrigerants
Economics of Refrigerants
a)Easy to detect
b)Flammability
c)The ozone depletion
potential (ODP)
d)Global Warming
Potential (GWP)
a)Low cost
b)Easily and regularly available

6. PRIMARY AND SECONDARY REFRIGERANT
 Primary refrigerants are those fluids, which are used directly as
working fluids, for example in VCR and absorption based systems.
 These are the refrigerants which cool the substance or space
directly by absorbing latent heat.
 It absorbs heat during evaporation in the evaporator and releases
heat energy during condensation in condenser.
t is also known as direct expansion system.

7. PRIMARY AND SECONDARY REFRIGERANT
 As the name implies, Secondary refrigerants are those liquids, which
are used for transporting thermal energy from one location to other.
In refrigeration plant a secondary coolant is used as cooling medium
which absorb heat from refrigerated space and transfer to primary
refrigerant in evaporator.
 Secondary refrigerants are also known referred to as brines or
antifreezes. Eg: If the operating temperatures are above 0°C, then
pure water can also be used as secondary refrigerant, for example in
large air conditioning systems

8. CLASSIFICATION OF PRIMARY REFRIGERANT
•Halo-carbon Refrigerant
•Azeotrope Refrigerant
•Inorganic Refrigerant
•Hydro-carbon Refrigerant

9. DESIGNATION OF REFRIGERENTS
• Refrigerant is internationally designated as ‘R’ and followed by
some numberlike R11 , R12, R612 etc.
R
Followed
by
2 Digit
Methane.
3 Digit
Ethane
The nos. assigned to hydrocarbon and halocarbon refrigerant have specific meaning
• The first digit no. right there is: Flourine (F)
• The second digit from right is one more than is: Hydrogen (H)
• The third digit from right is one less than is : Corban (C)
( When this digit is zero, it is omitted)
ASHRAE

10. The general chemical formula for refrigerant is
𝑪 𝒎 𝑯 𝒏 𝑪𝒍 𝒑 𝑭 𝒒
n+p+q = 2m+2
Example : Dichloro –difluoro- methane P=2, q=2, n=0, m=1
Here zero is omitted R12

13. INORGANIC REFRIGERENTS
Example :NH3 = R717
CO2 = R744
H2O = R718

14. SUBSTITUTES FOR CHLORO –FLORO-CARBAN (CFC)
(Freon) REFRIGERENTS: Formulas
𝑪 𝒎 𝑯 𝒏 𝑪𝒍 𝒑 𝑭 𝒒; n+p+q = 2m+2
The fully halogenated refrigerants like : n=0
R11= R011 = q=1, n=1-1=0, m=0+1=1; p= 2x1+2-1= 3;
(C1H0Cl3Fq) CCL3F1
R12 =R012 = q=2, n=1-1=0, m= 0+1=1; p=2x1+2-2 =2; CCl2F2
R13= R013= q=3, n=0, m=1, p=2x1+2-3=1, CClF3
R113; q=3, n=0, m=1+1=2, p= 2x2+2-3=3 ; C2Cl3F3
R114; q=4, n=0, m=2, p=2 ; C2Cl2F4
R115 , q=5, n=0, m=2, p=1; C2ClF5

15. SUBSTITUTES FOR HYDRO-CHLORO –FLORO-CARBAN (HCFC)
𝑪 𝒎 𝑯 𝒏 𝑪𝒍 𝒑 𝑭 𝒒; n+p+q = 2m+2
R22= R022; q=2, n=2-1=1, m= 0+1=1, p= 2x1+2- 1-2=1
= CHClF2
R123 = C2HCl2F3

16. HALOCARBON REFRIGERANTS
Halocarbon Refrigerant are all synthetically produced
and were developed as the Freon family of refrigerants.
 They are fluorocarbons of methane and ethane series.
 They contain 1 or more of these halogens (chlorine, bromine, fluorine)
 Non toxic, non-flammable, non-explosive, non- corrosive, non-irritant to
human body and eyes.
 Odourless, colourless not react with food product stored in the
refrigerated space.
 Will not react with lubricating oil.
 Has excellent thermodynamic properties
 Only disadvantage is ozone layer is damaged.

20. INORGANIC REFRIGERANTS
Inorganic refrigerant were exclusively used before the
introduction of halocarbon. These refrigerant are still in
use due to there inherent thermodynamic and physical properties.
•Carbon Dioxide
•Water
•Ammonia
•Air
•Sulphur dioxide

21. AZEOTROPE REFRIGERANTS
• This group of refrigerants consist of mixture of different
refrigerants which can not separated under pressure and
temperature and have fixed thermodynamic properties.
• A stable mixture of two or several refrigerants whose vapour
and liquid phases retain identical compositions over a wide
range of temperatures.
• Azeotropic mixtures are designated by 500 series
•Examples : R-500 :( 73.8% R12 and 26.2% R152)
R-502 : (8.8% R22 and 51.2% R115)
R-503 : (40.1% R23 and 59.9% R13)

22. ZEOTROPIC REFRIGERANTS
• A zeotropic mixture is one whose composition in liquid
phase differs to that in vapour phase. Zeotropic refrigerants
therefore do not boil at constant temperatures unlike azeotropic
refrigerants.
• zeotropic refrigerants are designated by 400 series.
• Examples :R404a : R125 /R143a /R134a (44%,52%,4%)
R407c : R32/R125/R134a (23%, 25%, 52%)
R410a : R32/R125 (50%, 50%)
R413a : R600a/ R218/R134a (3%, 9%, 88%)

23. HYDROCARBONS
Most of the hydrocarbon refrigerant are successfully
used in industrial and commercial installation . They possess
satisfactory thermodynamic properties but are highly flammable and
explosive.
•Growing use in very small commercial systems like car air-
conditioning system
•Examples:
R170, Ethane, C2H6
R290 , Propane C3H3
R600, Butane, C4H10
R600a, Isobutane, C4H10
Blends of the above Gases