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What about the energy use?... and a trip through the airport
I’m planning to develop some more ideas and articles around what I’d discussed last week. For those that didn’t catch it, I created a visual to simply explain what we can do to address the environmental problems with refrigerants (the fluorinated ones – what I call BigF).
In talking only about the refrigerants, some people might naturally ask the question. How does this fit alongside energy use? Is one more important than the other.
The short answer is that both energy and refrigerants contribute greenhouse gases, they are both important, but their relative contributions are going to change over time.
Systems that use refrigerants for cooling and air-conditioning, use large amounts of electricity globally, and a lot of that today is still fossil based. For many refrigeration systems, their energy use will be the largest source of emissions. Today.
What happens over time is worth considering, and we can use a simple system, such as the domestic refrigerator as an example.
Using rough figures, we can break the emissions profile into 2/3 from energy use and 1/3 from the refrigerants and foams (yes the insulation also contains f-gases to make the foam).
Without wanting to complicate things too much. These figures are based on older refrigerants with relatively high global warming potentials (GWP). The energy used is based on running the fridge continuously over a period of fifteen years on an average grid.
But what happens if you fit solar and storage to your house, so that your energy supply becomes zero carbon? The refrigerant becomes the sole emissions source.
You could buy a fridge today containing climate damaging (HFC) refrigerants and foams. You could plug it in today, into a fossil grid that may over the next fifteen years gradually decarbonise. However, the refrigerants inside will remain unchanged and still contain the same warming potential.
This also applies to other refrigerant containing appliances, such as heat-pump clothes dryers (as we spoke about last week), or air-conditioners. Anything containing BigF refrigerants.
If we were to take a large supermarket chain with many stores, the ‘morph’ from fossil electricity to clean electricity is likely to be more progressive. It also depends on the type of system and how well it is maintained. You may recall one of my earlier articles, where I first came across the problem. It was a supermarket system where the refrigerant emissions from leaks were higher than the fossil energy consumed for the whole store.
If you’re wondering if there is a way to calculate the combined emissions, there is. One of the more common ways is to use what is called the TEWI calculation (total equivalent warming impact).
I won’t provide a full breakdown of the calculation here today. However, it is based on both the energy used and the refrigerant emissions. Those from the leaks during the operational life of the equipment, and what is left when it is disposed of and how much potentially makes it to atmosphere.
It does have some limitations, but it is effective in taking into account the two sources of emissions, and allowing comparison between systems.
One of the things to keep in mind however is it doesn’t cover the whole life cycle. For example, the manufacturing emissions of refrigerants aren’t included. Some newer ‘low-GWP’ refrigerants, such as HFOs, have much higher manufacturing emissions. So, while the TEWI figures might look good for a certain refrigerant, when the manufacturing is considered, things may start to look quite different.
There are some in the industry that contend that only the energy efficiency and consumption of these systems are important. As we travel further along our net-zero journey, and our grids decarbonise, this wont hold.
For sure we will need to continue pushing for efficiency and demand reduction, because as we electrify everything, we have to make best use of every electron. But in doing so the refrigerant emissions are also going to become more relevant.
Where the F-gas hides
Each week I provide an example of where f-gases are utilised, or used to produce something. They are present in more things than most people realise… #wherethefgashides
I rarely fly these days. It just so happened that in the last week I took a flight to see family which is my excuse for the newsletter being a little later than usual.
I used the opportunity to contemplate where all the refrigerants might be hiding along the way. And there were plenty.
From the air-conditioned vehicle to the airport, to the air-conditioned terminal, with its chilled water dispensers (incredibly well hidden so most folks revert to buying bottled water), refrigerated vending machines, sandwich displays and kitchen cold-rooms. Then onward through the air-conditioned aircraft boarding gantry, pictured above.
For those curious, larger passenger aircraft don’t use refrigerant-based systems for cabin air-conditioning. They use air, bled off from the engines, which passes through what’s called an air cycle machine or ACM.
However, when parked on the tarmac without the engines running, they may use ‘ground air’ which may be supplied by refrigerant containing systems. You can also find refrigerants in the cargo hold in chilled freight containers. And you can also find HFCs in the lavatory fire suppression systems…
As we sat waiting for take-off, there was a well-crafted video on my screen about the airline’s net zero journey. Designed no doubt to make us feel a bit less guilty. Plenty of reverences to sustainable aviation fuel but not so much about f-gases. Perhaps it will come with time…
Right, that’s all for this week and ‘till next time
p.s. the title track from last week’s edition - Up to our necks in it - was from Sydney band Skunkhour circa 1995
Fixed stuff here for newcomers
There is lots of news every week from the cooling industry and plenty of newsletters that cover it well. The intention is to keep this newsletter focused on the most prominent f-gases (fluorinated greenhouse gases), the most common of which are refrigerants and importantly their environmental impact. That’s the lane I’ve chosen - I’ll do my best to stick to it.
Below is the seven (formal) greenhouse gases that countries and companies should track, report and hopefully reduce.
Carbon Dioxide (CO2)
Nitrous Oxide (N2O)
Sulphur Hexafluoride (SF6)
Nitrogen trifluoride (NF3)
There is also the still circulating, ozone damaging chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and the ‘new-generation’ hydrofluoroolefins (HFOs).
Hopefully you can spot the pattern.
Emissions from f-gases and refrigerants have been the fastest growing greenhouse gases over the past decade (more than CO2 and methane - check out IPCC WG3 summary for policy makers). They are also classed as super pollutants given their outsized global warming and other environmental impacts.
Some useful permalinks
The scale of the climate challenge can often feel daunting. This piece helps me take a step back and understand where we need to focus first - recommend a read.
There are plenty of technology solutions available to address the cooling and refrigerant challenge. You can find many of them here
Beware when the same entities who have contributed to the current f-gas problem propose you new solutions… This is a good place to get up to speed.