REFRIGERANT - SARKARI LIBRARY

Page Contents

What is a refrigerant?
→ A substance used to absorb and transfer heat in a refrigeration cycle.
What are the main classifications of refrigerants?
→ CFCs, HCFCs, HFCs, HFOs, hydrocarbons, inorganic, and natural refrigerants.
What does CFC stand for?
→ Chlorofluorocarbon.
What does HCFC stand for?
→ Hydrochlorofluorocarbon.
What does HFC stand for?
→ Hydrofluorocarbon.
What does HFO stand for?
→ Hydrofluoroolefin.
What are examples of natural refrigerants?
→ Ammonia (NH₃), Carbon dioxide (CO₂), and hydrocarbons (propane, isobutane).
Which refrigerants are considered environmentally friendly?
→ HFOs and natural refrigerants.
Which refrigerants contribute to ozone layer depletion?
→ CFCs and HCFCs.
What is the ozone depletion potential (ODP) of HFCs?
→ Zero (HFCs do not deplete the ozone layer).

What are the desirable properties of an ideal refrigerant?
→ Low boiling point, high latent heat, non-toxic, non-flammable, and stable.
Why is a low boiling point important in refrigerants?
→ It allows evaporation at low temperatures, improving cooling efficiency.
Why should refrigerants have a high latent heat of vaporization?
→ To absorb more heat per unit mass, improving efficiency.
Which property of a refrigerant affects compressor work?
→ Specific volume (lower specific volume reduces compressor size).
Which refrigerants have low Global Warming Potential (GWP)?
→ CO₂, ammonia, and hydrocarbons.
Why is ammonia (NH₃) used in industrial refrigeration?
→ High efficiency, low cost, and zero GWP.
Which refrigerant is highly toxic but widely used in industrial applications?
→ Ammonia (R-717).
Why are hydrocarbons like propane (R-290) used in domestic refrigeration?
→ They have low GWP and high efficiency.
What is a major disadvantage of hydrocarbon refrigerants?
→ They are highly flammable.
Why is CO₂ (R-744) considered a good refrigerant alternative?
→ It is non-toxic, non-flammable, and has zero ODP and very low GWP.

What is the chemical name of R-12?
→ Dichlorodifluoromethane (CCl₂F₂).
What is the chemical formula of R-22?
→ CHClF₂ (Monochlorodifluoromethane).
What is the chemical name of R-134a?
→ 1,1,1,2-Tetrafluoroethane (C₂H₂F₄).
What is the chemical formula of R-290?
→ C₃H₈ (Propane).
What is the chemical name of R-717?
→ Ammonia (NH₃).
What is the chemical formula of R-744?
→ CO₂ (Carbon Dioxide).
Which refrigerant is known as Freon-12?
→ R-12 (CCl₂F₂).
Which refrigerant is commonly used as a replacement for R-12 in cars?
→ R-134a.
What is the chemical formula of R-600a?
→ C₄H₁₀ (Isobutane).
Which refrigerant is widely used in domestic refrigerators today?
→ R-600a (Isobutane).

What is the main environmental concern with CFCs and HCFCs?
→ They deplete the ozone layer and have high GWP.
What is the Ozone Depletion Potential (ODP) of R-12?
→ 1.0 (High).
What is the ODP of R-22?
→ 0.05 (Lower than R-12 but still harmful).
Which refrigerant was first banned due to high ODP?
→ R-12 (CFC-12).
What is the Global Warming Potential (GWP) of R-134a?
→ 1430 (High but ozone-friendly).
Why are HFO refrigerants preferred over HFCs?
→ They have lower GWP and are more environmentally friendly.
What is the GWP of CO₂ (R-744)?
→ 1 (Very low).
Which refrigerant has the highest ODP?
→ R-11 (CFC-11).
Which protocol regulates the phase-out of ozone-depleting substances?
→ The Montreal Protocol.
What is the Kigali Amendment related to?
→ The phase-down of HFCs under the Montreal Protocol.

When was the Montreal Protocol signed?
→ 1987.
What is the goal of the Montreal Protocol?
→ To phase out ozone-depleting substances (ODS).
When did India ban the use of R-12?
→ 2010.
What is India’s deadline for phasing out HCFCs like R-22?
→ By 2030.
Which refrigerants are banned under the Ozone Rules 2000 in India?
→ CFCs and HCFCs above certain limits.
What is the alternative to R-22 in new air conditioners?
→ R-410A and R-32.
What is the phase-out target for HFCs under the Kigali Amendment?
→ 80% reduction by 2047.
Which refrigerants are being used as substitutes for CFCs?
→ HFCs (R-134a, R-410A), HFOs, and natural refrigerants (CO₂, NH₃, hydrocarbons).
Why are HFO refrigerants considered a good replacement for HFCs?
→ They have very low GWP and high efficiency.
Which refrigerant is commonly used in modern split air conditioners?
→ R-32.