What is the Refrigerant , deferent types of refrigerant

# .  What is the refrigerant w

#Definition : A refrigerant is a compound or mixture ,usually a fluid , use in a heat pump refrigerant cycle . the refrigerant most of cycle do phase change from liquid to a gas circulation in the pipe and back a again .refrigerant is the compound that absorb heat from the environment or body and release cold in the environment or body . most common refrigerant such as CFC (chlorofluorocarbons) , R134 , R22 more

  #.1  what does a refrigerant do:-  refrigerant is a compound typically found either a fluid or gaseous state . main purpose of the refrigerant that absorb heat from the room or body and provide refrigerant or air condition in the room or body 

# Selection of a refrigerant

Refrigerant have to be physiologically non-toxic and non flammable. thermodynamically, there is no working substance which could be called an ideal refrigerant. the choice of a refrigerant for a given application is governed mainly by the refrigerating capacity (very small, small, medium or large )and refrigerant temperature such as or air condition (5 degree C),cold storage (-10 to 2 degree Celsius) refrigerator (-25 degree Celsius), food freezing (-40 degree Celsius).etc 

# General data of refrigerant

                                   

         

Refrigerant	Designation	Chemical    formula	Freezing point
Water	R718	H2O	0.0
Ammonia	R717	NH2	-77.7
Carbon Dioxide	R744	CO2	-56.6
Tetrafluoro Ethane	R134a	CF3CH2F	-96.6
Ethane	R170	C2H4	-183.2
Propane	R290	C3H8	-187.1
Methane	R22	CHF2CL2	-160
Trifluoro methane	R23	CHF3	155
Monofluoro met	R11	CFCL3	-111

Refrigerant in use After the year 2000

ü  After the finding that CFCs ,and to a lesser extent HCFCs deplete the ozone layer, over 100 countries adopt  Montreal  protocol of 1987 to phase out CFCs in year 2000, and HCFCs by the year 2030. These refrigerants include R32, R134a, R143a, R236 fa,  . HFCs and HCs do not deplete the ozone layer. They can used even after 2030.

ü  Replacement for R11 :-  Replacement of R11 in large capacity  centrifugal machine for air conditioning  has posed problem. So far R123 with its of 27.82 degree celsice,23.71 degree Celsius, the NBP of R11 has been chosen as the most efficient option for R11 in centrifugal  chillers.

ü  Replacement for R12 :-  The replacement for R12 in unitary equipment has been the easiest .Its place for all practical purposes , has been taken  over completely by R134a.  compare the NBP of -26.1degree Celsius of R134a, which is very close to -29.8degree celiac the NBP of the R12.

ü  Replacement for R22 :-  As R22 an HCFC, its use is permitted till 2030. Also since  it is currently the most  favored  refrigerants in package units and chillers , its use continues . 70% of commercial refrigeration system still use R22.

ü  Replacement for R502 :- Presently R404A has found application in place of R502 . The of R404A is -46.22 degree Celsius  as against -45.6 degree Celsius  the NBP  of R502 .A 50/50 per cent R125 /143a blend is also an alternative to R502.

Ø CHAMICAL REQUIRMENT

ü  Flammability :- hydrocarbons, such as methane ,ethane ,propane and butane are highly explosive and flammable . ammonia is also explosive in a mixture with air in concentration of  16 to 25 per cent by volume of ammonia . None of the CFCs is explosive or flammable . Some of the HFCs which are being considered as alternation to CFCs because of ozone layer depletions problems , such as R152, R152a, R143, etc . are flammable .however , R134a is not flammable

ü  Toxicity :-  From the consideration of comparative hazard to life from gases and  vapours , compound have been divided in to six groups by underwriters laboratories, group six contain compound with a very low degree of toxicity . because of flammability and toxicity , ammonia is not use in domestic refrigerator and comfort air conditioning. And ammonia is the cheapest  refrigerant . and also its is environment –friendly . the future may see the return of ammonia in the very big way .

ü  Ozone depletion potential and global warming potential of CFC refrigerant :-CFCs is damage to the ozone layer ,which is produce to the refrigerator and freezer. Ozone layer is place upper to the  atmosphere and stratosphere. The earth ozone layer in the upper atmosphere and stratosphere is needed for the absorption of harmful  ultraviolet rays coming from the sun in the 1985,the world was shocked to find a gaping hole above antartic in the ozone layer that protests the earth from ultra violet rays. These rays can cause  of cancer. CFCs have been linked to the ozone layer depletion in addition, they act as green house gases. The have global warming potential as well. According to the international  agreement, the use of fully halogenated  CFCs that have high ozone depletion potential . the commonly use refrigerants R11, R12, R113, R114 and other they have phase out from the year 2000. But R22 countries to remain very popular as a refrigerant. Even with the measure take so far, as late as 2008, a 2.7 million squire kilometer ozone layer hole was detected above Antarctic.