Life Cycle Management of Refrigerants

The manmade refrigerants have impacted the environment and are the controlled substances under the Montreal protocol and the Kigali amendment. While the Montreal protocol and the Kigali amendment have addressed the production and consumption of refrigerants, the banks, that is the refrigerants in the operating equipment needs to be addressed at the various stages of operation. It is estimated that 148.1 M pieces of Room ACs will be produced in 2029 and the world growth rate in 2026 will be ~ 4.6%. STATISTA. The key growing markets are China, South East Asea and India. India is expected to grow by 10% for the next 12 years as per ICAP. The Room AC is a dominant segment in the HVAC as seen from the fig. 1.

As per the estimates in the report published by the International Energy Agency, nearly two billion air conditioners are in use worldwide and by 2050, the estimated population will increase to 5.5 billion mostly driven by China and India. This means that huge quantum of refrigerants is in the working systems. The design life of Room AC is between 10 to 12 years. Most of the units are not dismantled in the prescribed way and the refrigerant is released in the atmosphere. This is potentially a major contributor to the global warming. Refrigerant alone can mitigate up-to ~ 0.5 degC of 1.5 degC limit agreed as a target in the Paris agreement by 2100.

The refrigerant leakage is not only at the end of the life but also during the operation. The leakage rate depends upon many factors from design to installation and regular maintenance. Corrosion is also a major contributor to refrigerant leaks. India has around 40% refrigerant requirement in the service sector mainly to meet the need to replenish the refrigerant that leaks from the operating units.

It is estimated that around 10% of the units leak during the lifecycle. With this background it is essential to address both the leaks in operating units and disposal of refrigerants at the end of life. The mitigation strategy will have to address across the value chain and will include the design aspects apart from the servicing and disposal at the end of the life.

The refrigerants presently used across the HVAC products and systems are predominantly HFCs and they have high Global Warming Potential (GWP). The GWP of a refrigerant is the term used to understand the global warming potential of refrigerants with reference of CO₂ as unit one. The GWP of the most commonly used refrigerants is HFC 410A (2000), HFC 32 (675), HFC 454B (465), HFC134a (1400), HFC 404A (4000). If one kg of HFC 410A leaks it is equivalent to 2000 kg of CO₂ released in the atmosphere.

It is therefore essential and important to address the leaks and the end-of-life management.

Contributors leading to leaks

Various factors lead to leakage of refrigerant as below and should be part of the engineering design of the product.

• Pipe vibration: An Air conditioner has a Compressor which has multiple moving parts leading to compressor vibration. The compressor is usually mounted on rubber mounts to ensure that the vibrations are localized and they do not get transferred to the entire unit. However, the compressor is connected to the heat exchanger and few other components which are static thru copper tubes. From design point of view, it is critical that the interconnecting copper tubes geometry is designed to ensure that the vibrations do not cause material fatigue leading to rupture in the tubes.
• Brazing: A typical 1.5T Room AC will have around 100 to 125 brazed joints, joining cooper to copper, copper to brass and copper to steel. These joints can potentially fail unless the brazing material is selected for forming a good brazed joint and the brazing process is well controlled.
• Transport worthiness: The units are transported from the manufacturing plant to the end user in various modes of transport as well is handled multiple times and can get subjected to jolts, impact, on road vibrations and at times can get dropped during handling. This can lead to leaks and adequate care has to be taken at the design stage in terms of packing design.
• Environmental conditions and corrosion:  Selection of material (galvanic factor) can impact the sub systems and components in the HVAC products and systems. The components and sub systems containing refrigerant if impacted due to corrosion has potential to cause leak. The components copper tubes in heat exchangers, brazing material of copper to copper, copper to brass and copper to steel joints, steel in compressor body, receivers, suction accumulators, stainless steel in plate heat exchangers, brass in various types of valves, stainless steel body of thermostatic or electronic expansion valves, aluminium alloys in microchannel heat exchangers, mild steel shells in shell and tube heat exchanger need to be considered to prevent corrosion that can lead to leaks.

The environment in which the product gets installed and operated has to be understood as a first step. In case the application is known in advance, it is possible to build a mitigation strategy say saline atmosphere near seashore or in corrosive chemical environment. In the larger systems like chillers and VRF, wherein the customers are technically aware of the application, the design specifications are specified – and the manufacturers design the products as per the specifications. However, in most of the cases the environmental conditions are not known at the time of manufacturing as the products such as Room AC are designed for general purpose application. The manufacturers need to design products, select components and select and adopt manufacturing processes to mitigate the corrosion.

It is recommended that two categories of products are offered to the customers such as general purpose and highly corrosive environment compatible and give the choice to customer to select.

• Application: The contractors, installers and service technicians should carry out a detail study of the installation site for possible impact due to corrosion. Both macro and micro conditions should be evaluated. The micro conditions should be mitigated by relocating the installation location, however, to address the macro environment special consideration is needed depending upon the constituents in the environment. It is advisable to take help of an expert. Any shortfall in understanding can potentially lead to corrosion and leaks.

Role of service technicians

Service technicians need to play a major role to prevent the leakage. While the larger units are managed by the facility managers who have adequate knowledge about the HVAC systems, have comprehensive service contracts as well the technicians are well trained, the challenge is in the domestic Air Conditioners wherein the technicians are self-employed without formal training. They also do not have adequate tools and tackles resulting in poor installation and servicing practices.

The service technician is the final point of contact with the customer and he needs to understand the environment in which the air conditioner is installed from corrosion perspective and expected to advise the customer.  The installed location is also equally important. Installation with inadequate supply of air or with recirculating air in the outdoor unit will result in higher operating pressures and lead to leakage.

End of life management

End of life management is the most critical as it accounts for around 90% of the refrigerant to be managed. It includes recovery, recycling, reclamation, and destruction. The challenge is in recovering the refrigerant from the units.

The technology is well developed however, due to economic viability the recovery of refrigerants is seldom practised. Different policies are made and methods are adopted to ensure that the refrigerant is recovered, such as payback financing mechanism of the upfront collected amount thru higher duties, payment of money on delivering the refrigerant at the identified centres by the technicians from the corpus created at the stage of sale of refrigerant and as extended manufacturers responsibility of AC equipment. India has brought the End-of-Life management under the E-Waste rules amended in 2024. The manufacturers will have to ensure that the refrigerant is disposed, similar to the E-Waste material as per the guidelines and meet compliance.

Technologies are available for recovery, recycling, reclaim and destruction and standards have been developed for reclaimed refrigerant and reuse.

Economics

The bigger challenge is that the reverse supply chain for collection and recycling/reclaiming or disposal is either not existing or not efficient. The circular economy is not established. Service technicians have no incentive both in terms of investing time and effort or the economics to collect the refrigerant at the end of life.

The stakeholders across the value chain including the end customer have no motivation to manage the refrigerants. Worldwide compliance is a big issue. Investments are not happening as the collection is poor for the refrigerant to be recovered, reclaimed or to be destructed. The lack of awareness across the value chain on the effects of improper disposal of refrigerants is not creating sufficient pull.

Jitendra Bhambure is a former Executive VP R&D and Technology, Blue Star. Now he is an Independent Consultant and Advisor Technology Blue Star and Advisor CEEW. A Member of Refrigerant Technology Options Committee (RTOC) under (UNEP), he is also an Industry Representative in GoI, Ozone Cell, BIS, BEE and DPIIT.