Context: The Union Ministry of Power is planning to mandate a fixed temperature range (20°C to 28°C) for air conditioners in India to reduce energy consumption and promote public health.
Relevance of the Topic: Prelims: WHO Housing and Health Guidelines (2018), Rationale for New AC guidelines from the Centre; Common refrigerants used in ACs.
New AC guidelines from the Centre:
- The new directive will cap the operational temperature range of all new air conditioners (ACs) in India between 20°C and 28°C, whether in homes or commercial settings.
- Currently, many air conditioners available in the market allow temperatures as low as 16°C or 18°C, and heating settings going up to 30°C.
- Rationale: To reduce energy consumption and mitigate health risks associated with excessive cooling.
Why is this being proposed?
To Save Electricity:
- A study by the Bureau of Energy Efficiency (BEE) predicted that by 2030, India’s total AC load could reach 200 GW, putting stress on energy supply.
- According to the Power Minister, every 1°C increase in an AC’s temperature setting can save 6% of the electricity it uses.
- Mandating optimal temperature off AC to 24°C, the country could save 20 billion units of electricity per year.
To Improve Public Health:
- Many people set their ACs at very low temperatures (like 18-21°C), but this is not only uncomfortable for most, it is also unhealthy.
- Low indoor temperatures are linked to:
- Increased blood pressure due to vasoconstriction (narrowing of blood vessels and stress on the heart).
- Higher risk of hypertension and respiratory issues like asthma and infections.
- Poor sleep, especially in children and the elderly.
- Reduce lung function in children.
- Mental health issues like anxiety and depression, especially in persistently cold homes.
- WHO’s 2018 Housing and Health Guidelines recommend using 18 degrees Celsius as the minimum safe living-room temperature in temperate or cooler climates because cardiovascular and respiratory admissions were found to climb steeply below that threshold.
- A longitudinal study found that 16% of individuals over the age of 50, living in environments cooled to below 18°C, experienced higher blood pressure, lower vitamin D levels and reduced lung function.
- Standards like ASHRAE-55 and ISO 7730 recommend maintaining minimum indoor temperatures for comfort and safety. A lightly clothed person can comfortably release body heat at 20-24°C.
How do Air Conditioners Work?
- An AC works by removing heat from inside a room and dumping it outside.
- It uses a refrigerant that evaporates and absorbs heat, then gets compressed (which uses most of the power), and finally releases the heat through a condenser.
- The colder the temperature one sets, the harder the AC has to work and the more electricity it uses.
- ACs are most efficient when operating in a temperature range suited to their refrigerant, typically 20°C to 28°C.
What is a refrigerant?
- A refrigerant or coolant used in ACs takes out the heat of a room and throws it outside into the atmosphere.
- A refrigerant has to undergo phase changes to absorb and compress the heat to distribute cold fresh air into the room. It changes from a liquid to gas when it absorbs a room’s heat and then again gets back to its liquid form when the compressor compresses it.
- The ideal refrigerant can be selected considering certain factors like -- favourable thermodynamic properties, non-corrosive nature and safety features like its toxicity and inflammability.
Common refrigerants used in ACs:
- Chlorofluorocarbons (CFCs): phased out due to Ozone depletion.
- Hydrochlorofluorocarbons (HCFCs): less harmful but still risks Ozone depletion. Indian government plans to phase out the HCFC refrigerants by 2030.
- Hydrofluorocarbons (HFCs): Ozone-safe but have high global warning potential.
- Hydrocarbons (Propane and Iso-Butane): ozone-friendly, completely halogen-free and have the least global warming potential but flammable.
Thus, the case for moving towards a fixed temperature range on ACs is clear- supported by public health benefits as well as energy savings.