With many thousands of existing Air Conditioning and Refrigerant systems in use, many businesses are under pressure to convert their existing systems to operate with new lower global warming potential refrigerant gases. This has come about due to various laws that are in force, as stated here "The use of virgin fluorinated greenhouse gases (HFCS) with a GWP of 2500 or more to service or maintain refrigeration equipment with a charge of 40 tonnes CO2 equivalent or more is prohibited from 1 January 2020".
Credit BESA
This effectively means that businesses have to convert their existing system(s) or if there is a significant reduction in performance issue or equipment is just too old then replacement equipment might have to be sought.
There are many refrigerants in use depending on the equipment type and use. The following chart by Refrigerant supplier Climalife clearly shows the current alternatives available, as of August 2024.
Credit Climalife
There are some new revisions to the EU standard which the UK are closely aligned to. The latest revision introduces several additional maximum Global Warming Potential) GWP limits for new equipment being proposed for different applications, further GWP limits on refrigerants for maintenance of some applications and a very accelerated tonnes CO2 equivalents (TCO2e) HFC phasedown that will continue to reduce well beyond the current 2030 phasedown schedule.
The current HFC phasedown schedule reduces the TCO2e to 21% of the 2015 baseline level by 2030, but the new proposals will reduce TCO2e to just 5% of the baseline by 2030 with a complete phaseout of HFCs by 2050. HFO refrigerants such as R-1234yf and R-1234ze are not included in this phasedown and eventual phase out as they have very low and often zero GWP.
If you look at the most common refrigerant currently in use for Air Conditioning systems (R410a). As a blended refrigerant, R410A has been the choice of refrigerant for reducing damage to the ozone layer for years.
However, it still has considerable global warming potential when compared to newer modern alternatives, and its GWP remains an issue.
For R410a the most common alternative retrofit refrigerant that can be used is R32, which has an ozone depletion potential of zero, but also has around a third of the GWP of R410A.
According to global air conditioning manufacturer Daikin, if you converted all the worlds R410A air conditioners to R32, the impact from HFCs in 2030 would be reduced by around 19% of CO2, or 800 million tons.
R32 air conditioners are more environmentally friendly than R410A air conditioners, both in emissions and their energy efficiency.
With its lower Global Warming Potential, R32 has been designed to be in line with future legislation to reduce the environmental impact of air conditioning and refrigeration equipment.
By 2025, all refrigerant gases with a GWP greater than 750 will be phased put. R32 has a GWP of 675. Putting this into context, the most commonly used refrigerant R410A has a GWP of 2088, three times the GWP of R32.
Whilst the phase out of current refrigerants that don’t meet GWP requirements will be gradual, manufacturers have been quick to embrace the performance characteristics of the alternative R32 sooner rather than later.
Whilst the detail of the GB's own regulations are still unknown, there is enough information available to make sensible decisions. We know with certainty that the TCO2e phasedown will accelerate and that no-one can avoid moving to low or very low GWP options.
In the EU legislation, any GWP limited bans on maintaining equipment over the next 25 years do not cover refrigerants with a GWP <750, so installing new systems today using refrigerants with a GWP <750 is a valid strategy but continuing to install new systems using refrigerants with a GWP>750 may open up users to a situation where the expected equipment life is longer than the refrigerant availability.
One other consideration is energy efficiency. Currently there is no legislation for this, but there are many good reasons for ensuring the options chosen have good energy efficiency. Financially and environmentally, using the most energy efficient options makes sense. The lowest GWP does not always mean the best energy efficiency and lowest total emissions.
Retrofitting Challenges
One of the downsides to retrofitting a system with a new refrigerant is that there will be a compromise on system performance and efficiency. The original system was designed to handle another type of refrigerant which has unique thermodynamic properties.
In an ideal world, the entire system would be replaced to suit the new refrigerant and provide the ultimate performance, however, this is not always possible mainly due to financial constraints and many businesses will want to maximise their initial investment.
If this is the case, the only option is to then retrofit in order to comply with the current laws and regulations.
The cooling capacity will change with the use of a new refrigerant, so you’ll need to check that the new cooling capacity will be capable of meeting your demands.
Checking compatibility and suitability
Before retrofitting a system, you will have to assess the equipment us and type and components to ensure it will be compatible with a new type of refrigerant. For all the items listed below, it is essential that you record the manufacturer, model and serial number from the components data plate.
Recommended Actions - To Be Undertaken by a specialist (F-Gas approved A/C or Refrigeration specialist)
We can't expect you to become instant refrigeration specialists, so we recognise that this might not be as easy as you might think. We recommend that you contact a specialist to help you. Contact us for help.
Once you have obtained this information you should contact the equipment manufacturer or specialist contractor to discuss compatibility options. If you have a package unit this should be be reasonably easy, however, if your system is custom made or has many replacement components then it can be quite complex.
Below we detail (a non-exhaustive) series of steps that the specialist that need to be taken into account. The actual process they follow is down to the rules surrounding the equipment use and type.
N.B. While searching around the system for data plates, the specialist (F-Gas approved) specialist should record the normal operating conditions of the system by recording the pressure and temperature of the refrigerant from as many parts of the system as possible.
They will pay particular attention to the suction and discharge refrigeration pipework, then the evaporator and condenser, the superheat as well as the compressor amps. You’ll need to use this data to calibrate your new refrigerant.
Compressor:
The first first component they need to check is the compressor. The compressor is the heart of the system which forces the refrigerant to move around between all the major components. It’s also the most expensive component and where almost all of the electricity will be consumed so it’s important to get this right.
They’ll want to know the pressure and temperature limits of the compressor to ensure it will be able to cope with the new refrigerant. Additionally the oil used by the compressor will likely need to be changed to suit the new refrigerant.
Condenser:
The condenser is where all the unwanted heat will be rejected from.
This will need to reject all the heat from the evaporator as well as the heat produced by the compressor. They’ll need to check the condenser will meet the capacity of the compressor. If the replacement refrigerant being considered has a high glide then the condenser may need an increase in the surface area to suit the lower mean temperature difference.
Expansion device:
If the system utilises a thermostatic expansion valve, (which most will), then the expansion valve will likely need to be replaced as it will not be compatible with the new refrigerant.
The general rule of thumb is that if you compare the two refrigerant charts and there is a 3K difference in the pressure – temperature chart, then they will have to replace the valve. If it is under this value, then they might be able to adjust this if they have the ability to.
They'll also wants to ensure that any other valves used in the system, such as pressure control valves, will be able to cope with the new refrigerant and they will likely need to adjust these to suit also.
Evaporator:
If the new refrigerant is a high glide type, then this may cause a higher de-humidification rate as parts of the evaporator will have a lower temperature.
Valves and gaskets:
Unfortunately any gasket used around the system such as those used on the solenoid valve, service Schrader valves and o rings, will have to be replaced with new ones because the current oil/refrigerant will have caused the gasket to swell and when the refrigerant and oil is replaced the gasket will start to leak - which will mean refrigerant loss.
Additionally the replacement oil can react with these components and break down the material.
Lubrication oil:
The oil currently in use is also going to need to be replaced and its good practice to change the oil filters as well, if the system has these.
For this they’ll need to decide which retrofit refrigerant you will be using and find the corresponding, compatible, oil recommended by the supplier. It is essential that you check this oil is compatible with the compressor.
Pipework:
The pipework will also need to be assessed as the refrigerant used will likely have a different density and enthalpy which will result in different velocities and also pressure drop. The suction line and oil return lines are of particular importance.
Controller:
The controller may also need to be adjusted especially for the superheat as this will change with the refrigerant also.
Which refrigerant can your system move to? It depends on the type of system being used.
Credit: The Engineering Mindset
The refrigerant you will need to migrate over to, will depend on two things.
What type of system you have
How long the system will be operational for
In the image above you can see some examples of how that might look going forward. Check with your suppliers and specialists for more information.
High Alternative Refrigerant Costs
One of the biggest challenges is for the cost of alternative refrigerants in large air or water cooled chillers. A direct example of this is the amount of refrigerant that exists in a single 500KW Carrier 30XA Air Cooled Chiller. There would be 158Kg of R134a in there. As of August 2024, the current cost of R134a is approx £20.42/kg. Thats a total of £3,226.
The ideal replacement is R1234ze. The current cost is approx £58.23/kg. Thats a total of £9,248. Therefore just the refrigerant cost difference alone is nearly 300% more! Thats without the additional reclaim cylinder hire and labour.
A building like City Hall in London which is 12,000 sq/m will have a cooling capacity of around 150 watts per sq/m. Therefore a cooling capacity of 1800 Kw. Systems are usually over sized. Therefore, there will be 4 of the aforementioned chillers. As you can see an expensive option.
For the purpose of this exercise we are going to compare the old Refrigerant R410a vs the newer R32. For other refrigerants get in touch
Performance differences
Environmental Impact
One of the most significant differences between R32 and R410A is their environmental impact. R32 has a lower GWP of 675, compared to R410A’s GWP of 2088. This means that R32 is less harmful to the environment in terms of contributing to global warming.
Using R32 can help meet stricter environmental regulations and standards aimed at reducing greenhouse gas emissions. This is a critical consideration for businesses looking to reduce their carbon footprint and comply with environmental policies.
R32 is also a single-component refrigerant, which makes it easier to recycle and reclaim. R410A, on the other hand, is a blend of two refrigerants, making its recycling process more complex and less efficient.
Efficiency and Performance
Efficiency is another crucial factor when comparing R32 and R410A. R32 has a higher cooling capacity and is more energy-efficient than R410A. This means that air conditioning systems using R32 can achieve the desired temperature more quickly and consume less electricity in the process.
The higher efficiency of R32 also translates to lower operating costs. Users can expect reduced electricity bills and overall savings over the system’s lifespan. Additionally, R32’s superior heat transfer properties contribute to its enhanced performance and efficiency.
However, R410A has been used for a longer time and is well-proven in the field. Its performance is reliable, and it has been the industry standard for many years. While R32 offers better efficiency, R410A’s long track record of reliability is also an important consideration.
Safety
Safety is a vital consideration when choosing a refrigerant. R32 is classified as an A2L refrigerant, which means it is mildly flammable. Proper handling, installation, and maintenance procedures must be followed to mitigate any risks associated with its flammability. R410A, on the other hand, is classified as an A1 refrigerant, indicating that it is non-flammable and poses a lower risk in terms of flammability. This makes R410A a safer choice in environments where flammability is a significant concern.
However, R32 requires less refrigerant charge per unit of cooling capacity compared to R410A. This means that systems using R32 can have a smaller refrigerant charge, potentially reducing the risk associated with refrigerant leaks.
Cost
Cost is an important factor for both initial investment and long-term operation. R32 systems generally have a lower refrigerant cost compared to R410A systems. This is due to R32’s higher efficiency and lower required refrigerant charge, which can lead to savings on refrigerant costs.
Moreover, the improved energy efficiency of R32 translates to lower operating costs, providing savings on electricity bills over the life of the system. However, the initial cost of R32-compatible equipment may be higher due to its newer technology and the need for specialized components to handle its properties.
On the other hand, R410A systems may have a lower initial equipment cost since they are widely available and have been used for many years. However, the higher GWP and lower efficiency of R410A can result in higher long-term operating costs and environmental compliance expenses.
Key Takeaways
– Environmental Impact: R32 has a significantly lower GWP than R410A, making it a more environmentally friendly choice.– Efficiency and Performance: R32 offers higher efficiency and cooling capacity, leading to lower operating costs and enhanced performance.– Safety: R32 is mildly flammable (A2L), requiring careful handling, while R410A is non-flammable (A1) and poses a lower flammability risk.–
Cost: R32 systems can be more cost-effective in the long run due to lower refrigerant costs and improved energy efficiency, despite potentially higher initial equipment costs.
Choosing between R32 and R410A depends on the specific needs and priorities of the application, including environmental concerns, efficiency requirements, safety considerations, and budget constraints. Understanding these factors can help make an informed decision that aligns with both operational and sustainability goals.
Alternatives
Of course different sites will potentially have other refrigerants, especially those larger buildings with large air or water cooled chillers. Additionally they might be Hotels or Hospitality with freezers or stand alone cold stores or data centres with multiple large cooling systems.
Each site is unique and the new refrigerant to be used has to be carefully considered. Aside from the refrigerant itself is the potential impact on energy consumption
For advice, site survey, recommendations and suitable contractors who can undertake the conversion works please get in contact
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