Low Global Warming Potential Refrigerants

You probably have heard that the most popular HFC refrigerants being widely used today are global warming gasses. In fact, some popular HFC refrigerants have higher GWPs than the CFCs and HCFCs they replaced. A refrigerant’s Global warming potential (GWP) compares it to CO², the global warming gas produced by burning hydrocarbons. A GWP of 1 indicates that a gas has the same effect on global warming as CO². The retired popular air conditioning refrigerant, HCFC 22, has a GWP of  1760. HFC 410A that is now widely used in air conditioning applications has a GWP of 1924. It is actually worse! Meanwhile HFC 404A, popular in refrigeration applications, has a GWP of 3943. HFC 134a is popular in domestic refrigerators, commercial refrigeration, and car air conditioning has a GWP of 1300. These high GWP numbers have made HFC refrigerants the target of regulatory efforts to limit their use and replace them with more environmentally friendly refrigerants. Europe has moved aggressively, passing their F-Gas regulations. The ultimate objective of the F-Gas Regulations is to cut the availability of HFCs by 79% between 2015 and 2030. There will also be a servicing ban on HFCs with a GWP >2500 for certain sectors. Here is a link to a quick overview of the F-Gas regulations byMitsubishi.

While the US has not moved nearly as aggressively, there have been attempts by the EPA to regulate refrigerants based on their GWP. Worldwide regulatory restrictions on current HFC refrigerants has spurred development of lower GWP refrigerants. Manufacturers in the HVACR industry have been actively developing lower GWP alternative refrigerants.

HYDROCARBONS

Propane (R290), Isobutane (R600a), and R441A all have very low GWPs of (3, 3,0). They are all non-ozone depleting and non-toxic. Their limitation is their flammability – they are all highly flammable. In the US they are approved only for systems with a charge of 150 grams (5 ounces) or less. In Europe hydrocarbon refrigerants have been used in refrigerators and freezers for years. These refrigerants are now common in residential refrigerator and small commercial refrigeration units in the US. While highly flammable refrigerants are likely to remain a factor in small commercial refrigeration systems, it is unlikely that these refrigerants will be used in larger systems in the US due to our aversion for being sued and the large number of lawyers in the US.

CO² R744

It is interesting that the main global warming culprit, CO², is also a refrigerant with a very low GWP of 1. It does not deplete the ozone, it is non-toxic, non-flammable, and cheap. What’s not to like? Unfortunately, CO² has a critical temperature of 88°F. It cannot condense above 88°F. This means that CO² systems are not “normal” systems. CO² systems must either be transcritical or cascade systems. Transcritical systems operate at very high pressures of 1200 – 1500 psig on the high side. Cascade systems use the evaporator of one system to cool the condenser of another system. Either way, CO² systems are more complicated and expensive than traditional system. One place that CO² has taken root is in large scale commercial refrigeration rack systems. Complexity in large rack refrigeration systems is normal and the extra cost of the transcritcial components is offset by the savings in refrigerant cost. However, in smaller scale systems the cost of a CO² system is prohibitive. For a quick explanation of a transcritical system check out https://www.achrnews.com/articles/94092-co2-as-refrigerant-the-transcritical-cycle

AMMONIA R717

Ammonia refrigeration has been around since the earliest days of refrigeration. Ammonia has always been used in large scale food commercial refrigeration and freezing for food processing because of its efficiency and low cost. Unfortunately, ammonia (R-717) has many application challenges. It is toxic, somewhat flammable, and cannot be used with some metals, such as brass or copper. It will continue to be a mainstay of commercial food processing, but I doubt you will see it expand into other market segments.

LOWER GWP HFCs

There are some HFC refrigerants that have a GWP in the hundreds instead of the thousands. While these refrigerants are probably not long-term solutions, they can provide a way to drastically reduce the GWP footprint of a system without a drastic change in technology or design.

R 32

HFC R-32 has been adopted by many manufacturers in air conditioning systems sold outside of the United States. R-32 is an HFC with a lower GWP of 667. That is still not really low compared to CO2 (GWP 1) or ammonia (GWP 0), but it is considerably lower than R404A, R410A, or R134a. HFC32 has the advantage of being a relatively “normal” refrigerant, making designing systems to use it less challenging than say, CO². However, R-32 is flammable. While not as flammable as propane, it does burn. That precludes its use in most applications in the US, at least right now. The building and safety codes in the US do not allow a flammable refrigerant in systems where the air in the building flows directly over the evaporator. These codes make no distinction between A2L and A3 refrigerants. To them, flammable is flammable.  Manufacturers and code officials in the US are working to determine what new requirements an A2L refrigerant system should have to make it safe for use. The one place you will find R32 in the US is in window air conditioners. The EPA allows use of R32 in limited quantities in window units. Here is a link for more information on R32. 

R466A (Solstice N41)

Honeywell has developed an A1 rated, non-flammable HFC based refrigerant with a GWP of 733. Like R-32, R-466A provides a refrigerant with a much lower GWP than HFC refrigerants currently in use, but not really low. Its big advantage over R32 is that it is non-flammable. R466A achieves this by using a mix of 49% R32, 11.5% R125, and 39.5% R1311. R32 and R125 are the two components found in R410A. R1311 has been previously used as a fire suppressant. This blend performs similarly to R410A, making adoption relatively easy.  Here is a link to more information on R466A. 

HFOs

Hydrofluoroolefins (HFOs) are a special type of HFC. They have at least one carbon double bond, making them less chemically stable than a “normal” HFC which has all single bonds. Because they are less chemically stable, they do not persist in the atmosphere for long, and this reduces their global warming potential. For example, HFO1233zd has a GWP of 0. HFO1233zd is a low pressure refrigerant for chiller applications. It has an A1 safety rating and does not deplete the ozone. HFO1234yf has a GWP less than 1. It has an A2L safety rating – meaning that it is somewhat flammable. HFO1234yf is used in auto air conditioning systems. It has been what most auto manufacturers now use instead of HFC134a. Here is a link to more information on HFOs.

R1234ze

R1233zd

R1234yf 

Lower GWP refrigerants are the future of HVACR. Some old and some new. Understanding how to safely work with these lower GWP refrigerants will be an important part of all technician’s knowledge set going forward.

New Low GWP Non-Flammable R410A Replacement

This will be a short post because I don't know a lot of details yet. Honeywell is developing a new three part zeotropic refrigerant that can replace R410A. It has a relatively low GWP of 733 compared to 2088 for 410A, and most significantly, is non-flammable. Honeywell's trade name for it is Solstice N41, the ASHRAE number is R466A. It reportedly contains the same two chemicals as in R410A (R32 and R125). A third is added - trifluoroiodomethane (CF3I). This third component is currently used a a fire retardant. It also helps reduce the GWP of the mixture. The new refrigerant is not claimed to be a "drop-in" for R410A, but required design modifications are said to be minimal. The refrigerant is currently undergoing ASHRAE testing, but has received a preliminary A1 rating.  I have now told you all I know, and it did not take very long. Here are links to two articles about this new refrigerant.
https://www.coolingpost.com/world-news/secret-of-honeywells-new-refrigerant/
https://www.coolingpost.com/world-news/honeywell-announces-r410a-breakthrough/
 

Court Rules Against EPA SNAP Ruling

Two refrigerant manufacturers, Mexichem and Arkema, have successfully sued the EPA over their decision to start phasing out HFC refrigerants because of their global warming effect. The gist of the argument is that the law which established the EPA’s right to regulate refrigerants is specifically about ozone depletion, not global warming. The EPA’s legal right to regulate replacement refrigerants is limited to their effect on ozone depletion. The court ordered the EPA to redo their ruling with this in mind. Below are a couple of direct quotes from the ruling.

“The fundamental problem for EPA is that HFCs are not ozone-depleting substances, as all parties agree. Because HFCs are not ozone-depleting substances, Section 612 would not seem to grant EPA authority to require replacement of HFCs. Indeed, before 2015, EPA itself maintained that Section 612 did not grant authority to require replacement of nonozone-depleting substances such as HFCs.”

“EPA’s novel reading of Section 612 is inconsistent with the statute as written. Section 612 does not require (or give EPA authority to require) manufacturers to replace non-ozone depleting substances such as HFCs. We therefore vacate the 2015 Rule to the extent it requires manufacturers to replace HFCs, and we remand to EPA for further proceedings consistent with this opinion.”

The EPA still has to do their rewrite, and of course it is possible that they might choose to appeal to the supreme court. But for now, the HFC phase down has been phased out.

You can download the ruling and read it for yourself here:

https://www.cadc.uscourts.gov/internet/opinions.nsf/3EDC3D4817D618CF8525817600508EF4/$file/15-1328-1687707.pdf

Below are two links to other articles about this ruling.

http://r744.com/articles/7787/u_s_court_rules_hfcs_cannot_be_limited_by_current_epa_rules?utm_source=mailchimp&utm_medium=email&utm_campaign=Bi-weekly+Newsletter

http://cen.acs.org/articles/95/web/2017/08/Court-strikes-down-US-restrictions-on-HFCs.html

Alphabet Soup

Daikin just announced the release of R407H and the US EPA has added it to their SNAP list of acceptable refrigerants for both new and retrofit uses. 407H is designed to be a lower GWP refrigerant to replace R404A and R22 in commercial refrigeration applications. I confess, I did not know there was a 407G. I am often asked where all these numbers and letters come from.

The numbers for refrigerants which are mixtures of two or more refrigerants start with either a 4 or a 5. All zeotropic refrigerant numbers start with a 4 while azeotropic refrigerants numbers start with a 5. Zeotropic refrigerants separate when boiling; azeotropic refrigerants do not separate when boiling. The number after the 4 indicates the order that mixture of chemicals was tested by ASHRAE. For example, R401A was the very first. The letter after a zetropic refrigerant designates the order of testing for that specific mix of chemicals. For example, 407A was the first mixture of R32, R125, and R134a to be tested while 407H is the eighth. Please note that the letters for 400 series refrigerants should be upper case.

So what is the difference between 407A, 407C, 407H, and all the other 407 refrigerants? Just the percentage mix of the three ingredients. All eight versions of 407 have slightly different mixtures of the same three constituent refrigerants. A lot of this is done to tweak performance for a specific application or improve a particular characteristic, such as lowering the refrigerant’s GWP. 407H has a GWP of 1500 compared to 404A of 3922.

So what about the other refrigerant numbers, such as 22, or 134a, or (gasp) 1234yf? These describe the chemical construction of the molecules in these refrigerants. These refrigerants all consist of just one chemical compound. Compounds such as R12 or R22 are simple enough to be described without a trailing letter because there is only one way to build them. On the other hand, refrigerants 134a and 1234yf can be built many ways because they have more than one carbon atom. The trailing letters describe how the atom is constructed, which makes a difference in how it behaves. Note that these letters are lower case.

Deja Vieux

We have been here before. An outgoing administration is promulgating lots of final rulings in their last gasp and an incoming administration is working hard to undo those rulings. We the regulated, are caught in the middle.

SEER 13 SEER 12 SEER 13
Just before January 20, 2001 when Bill Clinton left office, the Department of Energy upped the minimum SEER from 10 to 13. The change was to take effect in 2006. ARI objected and the Bush administration agreed to drop the minimum from 13 to 12. The DOE published the new 12 SEER standard in May 2002. Several states as well as national environmental and consumer groups successfully sued.  On Jan. 13, 2004, the U.S. Appeals Court for the 2nd Circuit, based in New York, ruled that the DOE did not follow "proper procedures" when it adopted its 12 SEER standard in May 2002. The more stringent 13 SEER standard was reinstated.

This is an oversimplification of the actors and events, but tell the basic story. Instead of having from 2001 until 2006 to reinvent their product line, manufacturers had only from May of 2004 until January of 2006 because of the regulation wars. In retrospect, it would have been far easier to shoot for the 13 SEER target from the beginning and have several more years to accomplish it.

HFC Phasedown
Like a case of deja vieux, the outgoing Obama administration just signed a Global Warming amendment to the Montreal Protocol this past October and the incoming Trump administration wants to scrap all Global Warming initiatives. However, AHRI is not beating the drums to slow down or scrap the HFC reductions. Instead they are saying that what they really want is regulatory consistency and certainty. In other words, they don’t want to relive the 2001 – 2006 SEER wars.

Nothing is Constant but Change
There are mid-term elections in two years, and the ruling party almost always take a beating, meaning the senate may change hands in two years. If this election has taught us anything, it is that we cannot know for certain who will be heading up the government in four years. In eight years we are guaranteed to have a change at the top. It takes years to develop and test new products, and the last thing any manufacturer wants is to have the design parameters altered drastically and capriciously based on the latest election. Even if the challenges are steep, they can be met with a reasonable time for development if you don’t keep moving the goal posts.

To read more about the history of the SEER wars read this excellent article in the NEWS.
http://www.achrnews.com/articles/97373-how-we-got-to-13-seer

To read more about AHRIs position on the HFC phasedown, read this NEWS article
http://www.achrnews.com/articles/134252-kigali-agreement-creates-orderly-phasedown-of-hfcs

New EPA Rules

On September 26, 2016 the EPA issued a new Final Ruling updating the regulations for handling refrigerants. Don’t panic, there is plenty of time to prepare. For technicians, the first important enforcement date is not until January 1, 2018 and some parts do not take effect until January 1, 2019. However, you do need to prepare. There are more changes than I can list in a short blog post, but I will provide an overview and plenty of links to the information.

Mostly about Global Warming
Most of the changes have to do with limiting global warming by reducing the use and release of HFC refrigerants. Some of the more significant changes include requiring certification to purchase and handle HFC refrigerants, reducing the allowable leak rate for ozone depleting and global warming refrigerants, specifying regular leak inspection for equipment which has exceeded the allowable leak rate, and requiring record keeping when disposing of systems with more than 5 pounds of refrigerant.

Technician Certification
Staring January 1, 2018 technicians must be certified to purchase and handle nearly all refrigerants, not just ozone depleting ones. One curious exception is that sales of small cans of refrigerant for use in car air conditioning systems will not require certification. The cans will be required to have a valve, but sales to the general public will still be allowed.

Leak Rates Lowered
Starting January 1, 2019, the leak rates will all be lowered and will apply to HFC and replacement refrigerants as well as ozone depleting refrigerants. A few specific refrigerants are exempted from the venting prohibition and the leak requirements. These exempted refrigerants include carbon dioxide, nitrogen, water, ammonia, chlorine, hydrocarbons, and R441A. The leak trigger rates which require repair are now 30% for industrial process refrigeration, 20% for commercial refrigeration, and 10% for air conditioning and “other” uses. Note that the refrigerant charge level for these trigger rates remains at 50 pounds or more.

Leak Inspection
Beginning January 1, 2019, the new rules require regular leak inspection for systems that have reached the “trigger rate” requiring leak repair. The frequency of the required inspections is determined by the type of system and the size of the system charge. Quarterly inspections are required for commercial refrigeration and industrial process cooling systems which hold 500 pounds or more refrigerant. Commercial refrigeration and industrial process cooling systems holding at least 50 pounds of refrigerant but less than 500 pounds require an annual leak inspection. Air conditioning systems holding at least 50 pounds require annual leak inspections. When leaks are repaired, an initial system tightness verification is required before adding refrigerant. A second system tightness verification is required after the system is up and operating. Records of all of these tests are required.

System Disposal Record Keeping
Starting January 1, 2018 technicians disposing of systems with at least 5 pounds of refrigerant must keep records regarding the equipment and the refrigerant charge. Specifically, you must keep
The location, date of recovery, and type of refrigerant recovered for each disposed appliance
The quantity of refrigerant, by type, recovered from disposed appliances in each calendar month;
The quantity of refrigerant, and type, transferred for reclamation or destruction, the person to whom it
was transferred, and the date of the transfer. Note that you are not required to report the quantity of refrigerant recovered from each individual system, but rather, the cumulative quantity of refrigerant recovered each month.

Links to EPA Documents
This is just an overview. To really understand all the details you should consult the information published by the EPA. Here is a list of links to some of that information.

Advance Copy of Final Rule
https://www.epa.gov/sites/production/files/2016-09/documents/608_final_rule_pre-publication_copy.pdf

Subpart F—Recycling and Emissions Reduction
http://www.ecfr.gov/cgi-bin/text-idx?SID=085a41355598f2919b6655098a466757&mc=true&node=sp40.21.82.f&rgn=div6

Fact Sheet on New Regulations
https://www.epa.gov/sites/production/files/2016-09/documents/608_fact_sheet_technicians_0.pdf

EPA Page on Revised Regulations
https://www.epa.gov/section608/revised-section-608-refrigerant-management-regulations

EPA page on leak requirements
https://www.epa.gov/section608/stationary-refrigeration-leak-repair-requirements

HFCs not Going Anywhere

HFCs are not going away any time soon. I am sure you have all hear about the push to reduce or eliminate HFC refrigerants because of their global warming potential. This past weekend at Comfortech 2016 I sat in on a very informative session by Rob Yost on refrigerants. One big point was that low GWP replacement candidates for R410A are all rated at 2 or 2L for flammability. The reason is pretty straight forward. To be non-flammable a chemical must be relatively stable. However, that stability means it lasts longer in the atmosphere, which increases its global warming potential. In other words, low flammability and low global warming potential are somewhat opposites in terms of chemical properties.

The newest low GWP blends being developed are actually blends of both HFOs and HFCs. The highest pressure HFO developed at this time is very similar in pressure to 134a. Obviously that won’t replace 410A. However, mixing it with some higher pressure HFC refrigerants yields a much lower global warming potential than 410A at working pressures that are similar to 410A. However, this mixture will be flammable.

The current building codes in the US don’t allow flammable refrigerants inside buildings in most circumstances, so none of the refrigerants presently being studied can be used under the current building codes. The next revision for building codes is due out in 2018. However, the window for incorporating exceptions for lower flammability refrigerants into the 2018 code has already passed – and no exceptions or conditions for the use of 2L flammable refrigerants are in the upcoming 2018 code. That makes 2021 the closest date that flammable refrigerants could possibly be used inside buildings. Even though that is only a little over four years from now, we can be reasonably sure that no mass extinction of HFC refrigerants will occur any time soon.

Before we transition out of 410A to something else, the issue of using lower flammability refrigerants inside buildings will have to be addressed, and even then, it is likely that HFC refrigerants will be some of the components in the next generation of refrigerants.

Are You Ready for R-32?

Are you ready for R-32? R-32 is one of the two components found in R-410A. Some major air conditioning manufacturers have been studying R-32 for use by itself. Why? Primarily because R-410A has a high global warming potential (2088) – even higher than R-22 which it replaced. On the other hand, R-32 has a much lower GWP of 675. R-32 is an HFC compound, not a blend. So it has none of the problems of vapor charging, fractionation, and glide found in the zeotropes. It is also a very efficient refrigerant and operates at pressures similar to R-410A.  So what is the catch? Flammability.

R-32 has a 2L flammability rating. This means that it will burn, but it will not explode. There is no flash point. It will burn when ignited, but it self extinguishes when the ignition source is removed. Still, it burns. Safety in design and handling must be a major priority when handling flammable refrigerants. As global warming potential becomes more of an issue, the industry will be moving toward flammable refrigerants. In general, the more flammable a refrigerant is, the lower its GWP. Most non-flammable refrigerants all tend to have a high GWP while extremely flammable refrigerants such as propane, R-290, have a very low GWP.  (Note that this is not always the case. CO2 has the lowest GWP of 1 and it is not flammable at all.)

Daikin, the world’s largest air conditioning manufacturer, is already producing R-32 systems for sale in other parts of the world. Danfoss is also studying R-32. For more information on R-32, check out these links.

Danfoss

Daikin

AIRAH

HFC Agreement

Recently on June 7, 2013, President Obama and Chinese President Xi Jinping met for talks in Rancho Mirage, California. One of the agreements to come out of the talks was an agreement for both countries to work together to reduce HFC production. The statement reads

"Regarding HFCs, the United States and China agreed to work together and with other countries through multilateral approaches that include using the expertise and institutions of the Montreal Protocol to phase down the production and consumption of HFCs, while continuing to include HFCs within the scope of UNFCCC and its Kyoto Protocol provisions for accounting and reporting of emissions."

Basically, the big news is that the two biggest producers and users of HFCs agreed with each other to work on reducing their use. Europe has already started their reduction of HFC use and their regulation of F-gasses. F-gasses are their catchy phrase for all fluorinated refrigerants. I believe the F part tells us what they think of them.  There is no need for immediate panic. Notice that the agreement basically says they believe that reducing HFC production and use is something good to do. There are not yet any targets, timetables, or details. However, it clearly lays out that HFC refrigerants will be with us for a far shorter period of time than the CFCs and HCFCs they replaced. You can read more details and background in this White House Press Realease.