What Are HFCs and Why Are They Bad?

When they gained popularity in the 1990s, most looked at hydrofluorocarbons (HFCs) as ideal solutions that could replace ozone-depleting substances (ODS) like chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). However, their role in global warming as potent greenhouse gases is evident now, and the need for safer alternatives has never been more apparent. So, what are HFCs, how are they used, what is their environmental impact and how can we minimize any deleterious effects?

Climate and Clean Air Coalition
https://www.ccacoalition.org/content/cooling-solutions#solutions

What Are HFCs?

While a majority of greenhouse gases are by-products of different human activities like burning fossil fuels, industrial processes, deforestation, and agriculture, HFCs are intentionally manufactured for use in different applications. These synthetic organic compounds are comprised of carbon, hydrogen, and fluorine.

What Are HFCs Used For?

The most common use of HFCs is as refrigerants, although they also find use in fire suppression, foam blowing, and aerosols.

• Refrigeration and air conditioning. The largest source of HFC emissions is the refrigeration and air conditioning sector, including domestic refrigerators, commercial refrigeration systems, and vehicle air conditioners. Leaks during manufacturing, installation, and maintenance are major sources of emissions.
• Fire suppression systems. Several fire suppression systems, especially clean agent systems, use HFCs as extinguishing agents.
• Foam manufacturing. HFCs are used as blowing agents in the production of foam insulation, packaging, and other foam products.
• Aerosols. Although less common than in the past, HFCs still find use as propellants in some aerosol products.

From Then to Now

HFCs entered the picture after the Montreal Protocol came into effect on January 01, 1989. This landmark international treaty aimed to phase out ozone-depleting substances like CFCs and HCFCs. Widely used in refrigeration, air conditioning, and aerosols, CFCs and HCFCs were responsible for the depletion of the ozone layer that protects the planet from harmful ultraviolet radiation.

As the world transitioned away from CFCs and HCFCs, HFCs emerged as a seemingly ideal replacement. They were effective refrigerants and propellants, and importantly, they didn’t deplete the ozone layer. However, the fact that they cause emission with  high global warming potential (GWP) came to light later on.

The greenhouse effect helps trap heat from the sun, which keeps the temperature on earth comfortable. But people’s activities are increasing the amount of heat-trapping greenhouse gases in the atmosphere, causing the earth to warm up.  https://www.epa.gov/climatechange-science/basics-climate-change#greenhouse

HFCs, GWP, and Global Warming and Environmental Impact

The GWP of a gas measures its ability to trap heat in the atmosphere compared to carbon dioxide (CO₂) over a specific time period, typically 100 years. CO₂ is defined to have a GWP of 1, but HFCs can have GWPs ranging from hundreds to thousands. For example, HFC-134a, a common refrigerant, has a GWP of 1,430, meaning it traps 1,430 times more heat than CO₂ over 100 years. Some HFCs, like HFC-23, have even higher GWPs, exceeding 10,000.  This potency stems from their chemical structure. HFCs are fluorinated hydrocarbons, and the presence of fluorine atoms makes them exceptionally efficient at absorbing infrared radiation, thereby trapping additional heat in the atmosphere. The high GWPs of HFCs make them a significant contributor to global warming.

The most significant environmental impact of HFCs is their enhanced greenhouse gas effect and the role they are playing in accelerating global warming. As HFCs accumulate in the atmosphere, they trap more heat, leading to rising global temperatures. This contributes to a cascade of climate-related consequences.

• More frequent and intense heatwaves.
• More rapid melting of the polar ice caps and glaciers, disrupting ecosystems, and contributing to sea level rise.
• The loss of sea ice also affects weather patterns and ocean currents.
• Changes in precipitation patterns, resulting in droughts and floods.
• Ocean acidification, leading to an impact on marine ecosystems.
• Ecosystem changes altering plant and animal habitats, causing species migration, extinction, and ecosystem imbalances.
• Human health is impacted by heatwaves leading to heatstroke and other heat-related illnesses.
• Changes in precipitation patterns can result in food insecurity and lack of water availability.
• Increased frequency of extreme weather events can cause injuries, displacement, and mental health issues.
• Infrastructure, such as roads and bridges can be damaged due to extreme weather, particularly in coastal cities.
• Disruption to essential services, no access to basic amenities, can lead to significant economic losses.

Global Efforts to Phasedown HFCs

Recognizing the growing threat, the international community has taken steps to phasedown HFCs. The Kigali Amendment to the Montreal Protocol, adopted in 2016, is a landmark agreement that aims to reduce the production and consumption of HFCs globally.

This amendment has set specific targets and timelines for developed and developing countries to phasedown HFCs. It also provides financial assistance to developing countries to support their transition to suitable alternatives. Key aspects of the Kigali Amendment include:

• Phasedown schedule. Countries are required to gradually reduce their HFC consumption and production according to a specific schedule.
• Technology development. The amendment encourages the development and deployment of more climate-friendly alternatives to HFCs such as hydrofluoroolefins (HFOs) and natural refrigerants like ammonia, carbon dioxide, and hydrocarbons.
• Capacity building. The amendment provides support for capacity building in developing countries to help them implement the phasedown.
• Reporting and monitoring. Countries are required to report their HFC production and consumption data to ensure compliance.

The U.S., on its part, enacted the American Innovation and Manufacturing (AIM) Act in December 2020. It directed the U.S. Environmental Protection Agency (EPA) to phasedown the production and consumption of HFCs in the country by 85% before the end of 2036.

The Role of Alternatives and Technological Innovation

Given the environmental impact of HFCs, their successful phasedown depends on the availability and adoption of climate-friendly alternatives. Some new technologies are under development, and a few are already there for the taking.

Vacuum-Driven Evaporation of Water Cooling

If you reduce the atmospheric pressure applied to water, it evaporates at a lower temperature. For example, while the boiling point of water at atmospheric pressure (1,013 mbar) is 100^oC, it evaporates at 3^oC if its pressure drops to 8 mbar. This serves as the basis of water under vacuum cooling.

The biggest benefit of this new technology, unlike all others, is that it comes with a GWP of zero. In addition, it is non-flammable, non-explosive, non-toxic, non-asphyxiant, non-PFAS, zero ozone depletion, and it has a high heat capacity.

Hydrofluoroolefins (HFOs)

HFOs are unsaturated fluorocarbons with low GWPs. Their use as refrigerants is increasing in various applications, including air conditioning and refrigeration. However, there have been some concerns about flammability/ignitability, toxicity, persistent degradation, and thermal stability.  While HFOs are generally considered environmentally friendly, some studies suggest that their breakdown products, such as trifluoroacetic acid (TFA), can be persistent and phytotoxic.

Natural Refrigerants

Natural refrigerants such as ammonia, carbon dioxide, and hydrocarbons have very low or zero GWPs, but they present other challenges. For example, ammonia is toxic and may lead to severe health problems if inhaled or when it comes in contact with skin. Besides, it is corrosive and flammable, cannot be used with copper piping, and has a strong odor.

CO₂ is an asphyxiant and operates at significantly higher pressures than traditional refrigerants, requiring specialized components and equipment. Hydrocarbons are highly flammable, posing a significant risk in case of leaks or improper handling, and require specialized safety measures.

What Action Can You Take?

While international agreements and technological innovations are essential, individual and collective actions are also crucial to reducing the environmental impact of HFCs.

As an individual, you can:

• Choose appliances and vehicles with climate-friendly refrigerants.
• Ensure proper maintenance of refrigeration and air conditioning systems to prevent leaks.
• Support policies that promote the phasedown of HFCs.
• Reduce overall energy consumption.

Measures that businesses can implement include:

• Transition to HFC alternatives in their operations.
• Improve the energy efficiency of their equipment and processes.
• Support research and development of climate-friendly technologies.

Governments at the national level as well as the state and local levels also need to wake up to the fact that they need to take the right steps to address the negative effects of HFCs. They should:

• Implement and enforce regulations to phasedown HFCs.
• Provide incentives for the adoption of HFC alternatives.
• Invest in research and development of climate-friendly technologies.
• Educate the public about the importance of phasing down HFCs.

Conclusion

Given the environmental impact of HFCs, their phasedown is a critical step in mitigating climate change. The Kigali Amendment provides a framework for global action, but its success depends on the commitment of all countries and stakeholders. By embracing climate-friendly HFC alternatives, promoting technological innovation, and taking individual and collective action, it is possible to significantly reduce HFC emissions and protect our planet for future generations.

The transition away from HFCs serves as a powerful reminder that even solutions designed with good intentions can have unintended consequences. Fortunately, continuous research has led to newer and better alternatives, with vacuum-driven evaporation of water cooling being the new talking point of the industry owing to its wide-ranging applications and many benefits.