Info Nuggets

1. Commonly used refrigerant gases in ACs (past & present)

CFCs (e.g., R-12): Chlorofluorocarbons (banned); high ozone depletion potential (ODP), high global warming potential (GWP)

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HCFCs (e.g., R-22):  Hydrochlorofluorocarbons; (phased out in India from Jan 1, 2020) Moderate ODP and GWP

HFCs (e.g., R-134a, R-410A): Hydrofluorocarbons; phasing down under Kigali Amendment; no ODP, but high GWP

HFOs (e.g., R-1234yf): Hydrofluoroolefins; currently used; Low GWP, eco-friendly

Natural refrigerants (e.g., R-290 - Propane, R-600a - Isobutane): Hydrocarbons; currently used in India; Zero ODP, very low GWP, flammable

2. Environment-related bans and protocols

Montreal Protocol (1987): Banned ozone-depleting substances (CFCs and HCFCs).

Kigali Amendment (2016): Calls for gradual reduction of HFCs due to their high GWP.

India’s action:

Phased out CFCs (2010)

Phased out HCFC-22 (R-22) in AC manufacturing (2020)

Committed to HFC phasedown under Kigali Amendment (ratified in 2021)

Currently used refrigerants in India (ACs)

1. R-32 – HFC with lower GWP than R-410A (commonly used now)
2. R-290 (Propane) – Hydrocarbon with very low GWP, energy efficient
3. R-600a (Isobutane) – Used in refrigerators, eco-friendly
4. R-1234yf – HFO with near-zero GWP, emerging in newer systems

Important from Civil Services exam point of view

Short answer questions:

1. Name any two refrigerant gases that are eco-friendly and currently used in India.
2. What was the primary environmental concern with the use of CFCs in air conditioners?
3. Under which international agreement were CFCs and HCFCs banned?

Long answer questions:

1. Discuss the evolution of refrigerant gases used in air conditioners from the perspective of environmental sustainability.
2. Explain the significance of the Kigali Amendment to the Montreal Protocol in controlling global warming.

Analytical questions:

1. “While shifting from CFCs to HFCs solved one environmental crisis, it led to another.” Critically examine this statement in the context of refrigerant gases and climate change.
2. Evaluate India’s strategy for transitioning to eco-friendly refrigerants in compliance with international environmental treaties.