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Minimising Environmental Impact of Refrigerants

Shankha Lahiri, Construction Consultant, Genis Construction Ltd.

Refrigerant is a compound typically found in either a fluid or gaseous state. It readily absorbs heat from the environment and can provide refrigeration or air conditioning when combined with other components such as compressors and evaporators. Refrigeration and air conditioning applications have an impact upon the environment, contributing to ozone depletion and global warming. There are two main areas of environmental impact:

  1. Direct: The leakage of refrigerant gases into the atmosphere which can cause ozone depletion and contribute to global warming.
  2. Indirect: Refrigeration and air conditioning systems consume energy, which raises CO2 emissions and contributes to global warming.

Refrigeration, including air conditioning, is necessary for life and will continue to expand worldwide. Its impact on the environment is huge, even if refrigeration technologies can also be part of solutions for mitigating global warming (new sources of energy, heat pumps…). Many efforts have already been made. However, reduction in CO2 emissions and fluorinated gas emissions are challenges to be addressed on an ongoing basis.

1. Reduce Direct Impact

a)  Use a refrigerant gas with lower environmental impact: Look to use a refrigerant gas with zero ozone depletion potential (ODP) and low global warming potential (GWP). Linde has produced a summary list of refrigerant gases and their environmental impact.

b)  Lower the leak rates of your system: Refrigerants only create direct emissions when they leak to the atmosphere. Therefore Linde recommends that you ensure that your system is leak-tight, consider fitting leak-detection systems and follow a regular maintenance schedule.

c)  Ensure correct end-of-life treatment of refrigerant gases: Ensure that you recover and dispose of refrigerant gas correctly when maintaining, upgrading or decommissioning a system.

2. Reduce Indirect Emissions

a) Minimise the power consumption of your refrigeration or air conditioning system: For existing systems, ensure that you are regularly maintaining the system and using the correct refrigerant gas. Installing new systems may offer substantial energy savings, via modern technology using next generation refrigerants, including HFOs and natural refrigerants.

b) Use your refrigeration or air conditioning system less often: Improve insulation, install doors on commercial refrigerators, freezers and display cases, and change the temperature set-points for air conditioning.

In recent decades the impact, among other, of refrigerants on the environment has become a major issue. Indeed, the presence of large leaks in the cooling system, the responsibility of these fluids in the destruction of the ozone layer and increasing the greenhouse effect is well established. Spurred on by the scientific community and international organizations, the refrigeration sector carries over 20 years to change its practices. Replacement of Hydrochlorofluorocarbons and Chlorofluorocarbons by hydrofluorocarbons, has significantly reduced the concentration of chlorine in the atmosphere, which is responsible for the destruction of stratospheric ozone. But all these molecules turn out to be potent greenhouse gases that contribute directly to global warming. In addition, refrigeration systems consume electricity that contribute indirectly to the emission of large amounts of CO2.

Therefore, improving the energy efficiency of refrigeration systems and the use of refrigerants with low global warming potential (GWP) are priorities that require the refrigeration sector to perform new mutations. These are the environmental tools, such as life cycle analysis, which reflect the trade-off between these two factors directly and indirectly. The objective of environmental optimization is to adapt the architecture of the refrigeration circuit properties of a fluid with low global warming potential. To satisfy these criteria, two approaches are evaluated: The use of new synthetic molecules with low GWP, works with the architecture of the traditional cycle, in which they are adapted. The use of natural refrigerants and adapting the architecture of the properties of the fluid.

The refrigeration and air conditioning have an important impact on the environment

On the stratospheric ozone layer More than 90% of refrigeration equipment relies on vapour compression using refrigerants and this figure will not change in the near future: other technologies do not generally have enough efficiency. Chlorinated refrigerants (chlorofluorocarbons – CFCs, and to a lesser extent, hydrochlorofluorocarbons – HCFCs) contribute to the depletion of stratospheric ozone if released into the atmosphere due to equipment leaks or if refrigerants are not properly recovered when disposal of the equipment takes place. CFCs and HCFCs are gradually being phased out thanks to the Montreal Protocol. Current measurements of the ozone layer show overall stability and probable recovery to the previous level around 2060. They are often replaced by hydrofluorocarbons (HFCs) which do not deplete the ozone layer but are potent greenhouse gases, as are HCFCs, when released into the atmosphere. CFCs were also greenhouse gases and their global warming potential was much higher. The impact of the Montreal Protocol is thus also positive regarding global warming. However, it is not enough.

Refrigerant recycling

Through extensive chemical and mechanical processes, used refrigerants are “reclaimed” to meet stringent purity levels and then they re-enter the marketplace for use in consumer or industrial applications. It is important to note that refrigerant reclamation is different than refrigerant recycling. The recycling process simply removes contaminants so the refrigerant can be reused in the same equipment or in equipment owned by the same individual; recycled refrigerant is not eligible for resale. During reclamation, extensive filtering, drying, distillation, and chemical processes strip the refrigerant of impurities to ensure the gas meets or exceeds ARI-700 purity standards, which are the same standards required of virgin refrigerant. Ultimately, your refrigerant goes to an EPA-certified reclaimer. Going straight to the source eliminates the middleman and usually results in higher payouts. In addition to offering payment, your reclaimer should provide you with paperwork that documents that your recovered refrigerant was handled according to EPA regulations. In India it is developing day by day and now there is an awareness regarding this !

As need arises to save ozone depletion layer and environment it becomes necessary to search the refrigerants having various properties eco friendly in nature and consequently the concept of ideal refrigerant originate. In addition to having the desired physical properties, an ideal refrigerant should be non-toxic, nonflammable, fully stable inside a refrigeration system, environmentally begin even with respect to decomposition products, and easy to manufacture. It also should be self-lubricating (or at least compatible with lubricants), compatible with other materials that are used to fabricate and service refrigeration systems, easy to handle and detect, and low in cost. Furthermore, it should not require operation at extreme pressures. It is a very long list of qualities and none of the current refrigerants can be considered as coming close to the ideal one.

About the author

The author is a Building Energy Conservation Consultant with 9 years of experience. As an energy consultant he helps companies to understand their energy usage and its utilization correctly. His work includes conducting research into and analysing the company’s current energy usage, writing reports and mapping the total energy usage, presenting findings, ideas and opinions.

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