ASHRAE Journal:
ASHRAE Journal presents:
Ryan Shanley:
Welcome to this episode of the ASHRAE Journal podcast. I am Ryan Shanley, ASHRAE's senior manager of standards, and today I will be discussing ultra-low GWP, global warming potential refrigerants, with our guests Doug Reindl and Stet Sanborn. So, if you guys want to go ahead and introduce yourselves.
Doug Reindl:
Hey Ryan, it's Doug Reindl. I'm a professor at the University of Wisconsin-Madison, and I also direct a organization here called the Industrial Refrigeration Consortium. I've been a long-time ASHRAE member, and I'm an ASHRAE fellow and I'm also a member of the ASHRAE Standard 15 committee.
Stet Sanborn:
Great to be here. My name is Stet Sanborn, so I'm vice president for engineering at Smith Group. I lead our engineering team out of San Francisco, so definitely on the design side for new buildings and retrofits. And then, relative to refrigerants work and general decarbonization, I sit on ASHRAE's task force for building decarbonization executive committee, so overseeing a lot of the work of how we're incorporating decarbonization throughout the structure of ASHRAE and helping give direction to various committees on areas that we can all collectively support efforts around decarb.
Ryan Shanley:
Great. So, to get our discussion started off, maybe, Doug, if you want to just give a little background on refrigerants, maybe just like what the different safety classes are, then that'll help inform what some of the issues that will come up with trying to transition to ultra-low GWP refrigerants might be.
Doug Reindl:
Yeah. So, ASHRAE has a standard, ASHRAE 34, that establishes the designation, the number designation for each refrigerant uniquely, and it also establishes a safety group classification for each refrigerant. The safety group classification is an alphanumeric string that describes the toxicity of the refrigerant and also its flammability. So, you'll hear us refer to A1, or A2L, or A3 refrigerants. The A is the toxicity flag, and it's using a 400 part per million threshold. If the refrigerant has health effects at concentrations that are less than 400 parts per million, it's considered a higher toxicity refrigerant. And for the refrigerants that have health effects that are equal to or greater than 400 parts per million, it's classified as a lower toxicity or a class A refrigerant.
The flammability is the next index of the safety group classification class one refrigerants don't propagate flames, and that's measured in a laboratory setting at a specified temperature, usually 60 degrees centigrade. And then, class two and 2L are flammable refrigerants, slightly flammable. And the distinction between the two and the 2L is the flame speed. So, there's a specific lower flammability limit threshold that's set and also a heat of combustion limit that's set. But the 2L is a slower flame speed propagation. It's a threshold of 10 centimeters per second. And then, the Class 3 flammable refrigerants are considered higher flammability. Those are lower flammability limits. That's a lower concentration threshold which they will ignite and they're usually faster flame propagation to higher heat of combustion. So, Class 3 are what we would call the highest flammability, and Class 1 are no flame propagation.
Ryan Shanley:
And just to give everyone an idea, when we had discussed this topic earlier between ourselves, there was a lot of references that will come up again to a refrigerant titled R290, which is classified as an A3, which means it is very flammable, and eventually, it just decided to look at the ASHRAE refrigerant tables and see, okay, what's R290, and it was propane, so that made sense. Obviously, that's very flammable.
Doug Reindl:
Yeah, and that's Standard 34 that sets the numbering for each refrigerant, so we might also talk about our 600A, that's isobutane, and that's another A3 refrigerant that's used in some products today, most notably like domestic refrigerators.
Ryan Shanley:
Okay. So, since what we're discussing is regarding the global warming potential of refrigerants, obviously, climate change is a big issue that is facing the entire planet. And so what we want to discuss is what does it look like to try and transition from current refrigerants which have a higher GWP, global warming potential, to lower GWP? And some of those are A3s, which as we've noted are very flammable. So, what does that look like to try and move from less flammable refrigerants to more flammable refrigerants in order to reduce the global climate impact?
Stet Sanborn:
I could jump in and lay some context because I'd say that this whole process is multifaceted, and there's been a tremendous amount of work that's already been done in the market in the transition to allowing the A2Ls. As Doug mentioned, there was actually a lot of learning that happened in terms of what needs to happen from stakeholders and manufacturing around that safety, not just for safety. And right now, for the context of why A3s are even on the table for discussion, really, Ryan, goes back to your point about climate impact. We're seeing from the design side a request from owners, developers, large portfolio owners that have either ESG environmental reporting requirements or broader sustainability goals within their own portfolios. They're asking for what I would call whole life carbon solutions.
Traditionally, ASHRAE has been at the forefront of energy efficiency for a very long time, and energy efficiency translates more to that operational carbon impact. Where are you getting your energy from? Is it combustion on site, or is it from the power grid? There's been a lot of focus on that operational component. From a portfolio standpoint, as folks are looking at whole life carbon, they're looking at all the other mechanisms that have a climate impact. And so that includes fugitive emissions, leakage of refrigerants, end of life, loss of refrigerants that may not be recaptured during the decommissioning of a product, and things like that.
And so, now, all of a sudden, there's a lens of looking at our broader impact beyond just the energy efficiency or the operating efficiency of our buildings. And so that's spurred the conversation of what can we do beyond traditional refrigerants and even the A2Ls that the market has already begun to transition to. But, I mean, Doug, who was heavily involved in that transition of even looking at the A2Ls, and so that process itself, I think, leads to a really good roadmap of what needs to happen from a research standpoint, from a safety analysis standpoint and market adoption as we look at some of these more flammable A3 class refrigerants
Doug Reindl:
I also think that that's a good background. I mean, going back a little bit farther, depending on how you count, we're in the fourth or fifth phase-out of different classes of refrigerants, and so one of the issues that I'm hearing is there's owners that just have phase-out fatigue. And they're looking at now with the AIM Act, the phase down of HFC refrigerants, and those refrigerants, by and large, have a fairly high global warming potential. And then they look at what's available in this new class of refrigerants, the A2Ls, and the GWPs are three-digit. And they're, I think, challenging themselves because they look at their roadmaps into the future and they go, "Do we want to transition again? And are these A2Ls a step into the low or ultra-low GWP refrigerants?" And so, instead, I think you've been hearing maybe some of the same thoughts, and I think phase-out fatigue is another factor here.
Stet Sanborn:
Yeah, absolutely. I mean, we're working with our clients. There's several layers that they're thinking about in terms of their operational capability within their own portfolio. You have an initial procurement of a building and the equipment that they might be buying out on day one, but they're looking at equipment that's been installed on their campuses or within their portfolios for 15 years, 30 years. And so there's layers of this transition that impact how they even plan their broader operations and maintenance across their portfolio. And so this transition to A2Ls, and as Doug mentioned, we might be talking about refrigerants that have GWPs of 500, 700, within that range.
They're looking ahead at what the regulatory pressures that they're seeing either through phase-out or vision to the future of what reporting might be required for whole life carbon impacts, including Scope 3 emissions. And they're like, "Do I really want to have an interim step?" Because they've already taken several steps. And so the questions that we're getting from our clients are, "Can we just jump all the way to whatever the end goal is? Just tell me what the end goal is. I just want to go to the end goal. I don't want to have to have 18 steps."
Doug Reindl:
Will the real refrigerant please stand up?
Stet Sanborn:
Exactly. And the challenge there is that the end goal hasn't gone through necessarily the same safety reviews in North America that we've gone through for all the other transition steps. And so that's the crux is that they're getting pressure from just being able to maintain their operations and put up a roadmap for maintenance and keeping everything going. They're trying to look at the big picture. At the same time, the market in North America doesn't really have product available in all classifications of equipment to jump right into, and so it's a challenge. It's a market transition challenge.
Ryan Shanley:
And to add a little more context on some of the push towards this transition, about two months ago, in March, the three of us were actually invited to a meeting with the White House Climate Policy Office because the US government currently is looking at how can we get ahead of this because, as Stet mentioned, this seems like it would probably be the endpoint instead of trying to just progressively move to lower GWP refrigerants in steps. And so there's a number of things that would not probably immediately come to mind as to what may be needed from a regulation standpoint.
I know at one point there was mention of Department of Transportation regulations because there are limits on how much of a refrigerant can be on a truck, for example, based on the flammability. So those may need to be revised if, say, a 18-wheeler is going to be transporting a bunch of air conditioning units full of A3s, they may need to revise those regulations and figure out how to do that safely. And so, one of the major questions that was posed to ASHRAE is ASHRAE has two standards, which are Standard 15 and 15.2, which are safety standards for refrigeration systems. And the 15.2 is focused more on residential, 15 is more commercial-focused. And the question was, well, what are the standards doing to incorporate these A3s into the safety considerations? What is the timeline for that? What else can be done to support this? So, if Doug or Stet, you want to talk a little more about that.
Doug Reindl:
I'll maybe start off, and Stet, you can chime in. I think one of the things that we agreed on in the meeting that you had mentioned, Ryan, was that safety is the number one priority. Whatever we're going to transition to, it has to be done safely, and we hold the safety of the public and those that occupy buildings and facilities that use these refrigerants, that's paramount. So, that's a recognition. And when you talk about transitioning to these ultra-low GWP refrigerants, which, by and large, are A3, the higher flammability classification, okay, how do we do that? How do we utilize these safely? And so 15.2, which is really single-family dwellings, townhomes, residential type dwellings, that's the target for that standard. And that was newly published in 2022. And as it stands right now, that standard doesn't even permit A3 refrigerants to be used.
And so we have to look at, okay, what do the application of these refrigerants mean for residential dwelling? And there's technology that's being used elsewhere outside of North America that are modular units that have all of the A3 refrigerant like propane contained within the outdoor unit, and then they're using secondary fluids to go into the residence. And I know Stet's very familiar with those. But for us in North America, at least for standard 15.2, that's not even an allowed refrigerant for use. And so we need to look at, okay, what does that mean for that application? What are the setback requirements? How do we apply this class of refrigerants, and mostly propane, it's going to be mostly propane for that. How do we do that safely?
And then, for Standard 15, actually Standard 15 has what I would call reasonable allowances for use of A3 refrigerants in non-residential applications. And so there are A3 refrigerants that are finding use in some applications, but I would still say that it's pretty limited, and there's a need to dig more deeply into what are the safety considerations if we continue to grow the use of these ultra-low GWP refrigerants that are higher flammability.
Stet Sanborn:
Yeah, I think one of the interesting things that's come out from the meeting at the White House was really how, as a coalition of agencies, and entities, and groups, can we move the work needed to take this forward. How can we collectively? And so it's not just ASHRAE. It's in combination with UL. It's in combination with the national labs. There's actually been some incredible research that the national labs, including Oak Ridge National Lab, have already done in optimization of equipment with A3 refrigerants like propane, heat exchanger optimization, trying to get the charge volumes as low as possible and still see high efficiency. I would say there was a very strong interest in propane in the market, mainly because, as Doug mentioned, there's a number of products, indirect system products, that are available in Europe, really, I'd say in the last year, have come online that you can purchase.
And so what are the impacts on how does that go through the same regulatory regime in North America? Because as I mentioned, even when, say, ASHRAE 15.2 adopts that safety standard, then the testing methodology needs to follow up with that so that manufacturers can put their products through a testing regime and get a stamp of approval that it's either gone through UL listing or a similar regulatory review from a testing standpoint. I think something that folks don't also realize is that in parallel to that, as ASHRAE, we're not just interested in what refrigerant goes into the product, but we're also, in parallel, trying to drive efficiency of equipment across the board as we march towards reduced operational carbon. And so as we introduce new refrigerants into classes of equipment, we need to then, in parallel, at what the impacts of that on efficiency standards like 90.1, 90.2 are going to be.
I obviously have a very strong fondness for indirect hydronic-based systems. It's where my passion lives from a design standpoint. But every time we add another loop to a system, another heat exchanger, another transition, you do take an incremental hit on efficiency. And so we want to make sure that as we're looking at these new types of equipment that can be deployed that we're able to do so that still continues ASRHAE's drive towards increased efficiency across the board. And so it's another layer, I'd say, to that onion, if you will, of trying to pair both the safety standard with enhanced performance.
The nice thing is that propane or R290-I prefer to call it R290. The nice thing there is that, from a performance standpoint, it actually does quite well, especially when we look at cold climates for making space heating and domestic hot water applications. So, it has really great performance characteristics that will help augment that conversation, especially for making some elevated temperature water. Upwards of 160 degrees Fahrenheit are achievable, which is especially appealing as we look at retrofits where we're trying to do boiler replacements and multifamily buildings in homes in cold climates. It's really attractive.
But that goes back to Doug's point about what are those safe installations. It's very different to think about a piece of equipment that's going to sit inside the envelope of a building versus outside and how far away. Propane, amongst its many benefits, also has some challenges from a deployment standpoint. It's heavier than air. It tends to pool. Anybody who's used to having a large propane tank as part of their combustion-based heating system knows that you have to be very careful about leaks settling into basements or window wells or stairwells that go down below grade. Those are all risk factors, and so we need to make sure that we're moving in a safe direction and that we have some uniformity from that safety standpoint so that everybody's playing by the same rules.
Doug Reindl:
So, that's an interesting point, Stet, that we think about other fuels, whether it be natural gas or propane that we use for heating, particularly in cold climates, and one of the benefits of those fluids that are used for heating is they typically have an odorant that's added to them. So, when there is a leak, the homeowners know about it. They know that they need to call for help and don't turn on any lights or use the phone, that sort of thing. And so, one of the challenges, and we've been talking about it with the renewed interest or re-interest in A3s, is that it's possible to find odorants that could be added to the refrigerant because we know that the traditional odorants that are used in propane or natural gas get stripped out from the refrigerant circuit with the filter dryers.
And so there's actually a push to identify are there odorants that could be added to the refrigerant that don't materially affect its thermodynamic performance and don't create other sorts of issues in the system that we don't want and that would be livable. They would survive circulating within the system and not get taken out by filter dryers. And so those are important things too to help its safe use in applications where now people are, I think, they're pretty readily attuned to natural gas leaks and propane leaks, and they know what to do. Can we find a similar strategy with hydrocarbon refrigerants, propane, for example?
Ryan Shanley:
So, that brings me to a question regarding that the reason we're looking at A3 is because of their ultra-low GWPs, but there are some Class 1 or 2L refrigerants which also have ultra-low, such as ammonia, air, ironically, in my opinion, carbon dioxide, R1234YF. So, why are those not good alternatives to look at? Is it because of safety issues, efficiency, primarily, those sort of things?
Doug Reindl:
Well, maybe I'll start. Stet, you can jump in. So, I've dealt a lot with ammonia. I have a lot of experience with that, but it's pretty much been relegated to the industrial sector, so food processing facilities, large refrigerated distribution facilities. It's ubiquitous. That's the refrigerant they use. So, in that sort of space, they've been using that refrigerant for 150 years. They don't know this thing called refrigerant phase-out, and they live in their own world, and they keep using that refrigerant. And environmentally, it has a zero global warming potential and zero ozone depletion potential. But from a safety group classification, it is a B2L, higher toxicity, slightly flammable, like the A2Ls.
And some of the data that's compiled in ASHRAE Standard 34, one of the measures is what's called the OEL, the occupational exposure limit. And for ammonia, it's pretty low. It's 25 parts per million. So, in high concentrations we don't want to have people potentially being exposed to that refrigerant, so that's the bad news. The good news is that people know it's there. It's a very distinct odor. Most people can smell it at single-digit concentrations, and they generally want to go in the other direction. And so we call it self-alarming.
In terms of application, well, our standards prohibit the use of ammonia as a direct refrigerant in a non-industrial environment, so we wouldn't even allow it. Could it be used as an indirect refrigerant? Yes, it could. There's really not been the effort put into the development of technology to use it other than in industrial applications. And it has some challenges. For example, it doesn't get along well with copper. And so if you think about the construction of air conditioning equipment, copper coils, copper tubing, copper piping, that sort of thing, and with ammonia, that's just not possible. So there is a bit of a, we'll call it a system performance hit. It's an efficient refrigerant thermodynamically, but now, when we have to use things like aluminum heat exchangers or stainless steel heat exchangers, it doesn't do quite as well from a heat transfer standpoint compared to a copper heat exchanger.
So, ammonia is out there. I think it has its niche. Whether it will grow into non-industrial uses, we'll see. CO2, a lot of activity in CO2. It's starting to pick up in the US. I think there's two issues that I continue to see and here. One is, I mean, the efficiencies are pretty poor, quite honestly. And to Stet's point, if we're looking at whole life carbon, we have to factor in what is the operating efficiency of the refrigerant, even though its GWP is one. I mean, CO2 is the benchmark.
The other issue is you get really high design pressures, and particularly for systems that are going to run transcritical. And so that becomes not only a design issue and a cost issue, but that has its own inherent safety issues. And I guess I would say the third piece of this is that, because of its comparatively poor operating efficiency, there's a lot of additional components that get integrated into these systems to try to prop up their efficiency and make them less energy hoggish, and that just makes them more costly and more complicated. That's the challenge. The last thing I'll say on YF is it is being used primarily in mobile air conditioning systems, not so much in what I would call traditional HVAC applications. And I don't expect that to change a lot, quite honestly, but we'll see what the future holds.
Stet Sanborn:
Yeah, the really interesting thing around all of these refrigerants is that it's not, and I think this is certainly the perspective of those of us that volunteer with ASHRAE, is that we're not trying to pick a single winner that's going to be the refrigerant that solves all problems. It's really trying to open up the field so that we can find the refrigerants that are the best match for the types of conditioning that we're trying to do. So, when we look at transcritical CO₂ heat pumps, which have really, within the last five years, broken into the market in any sort of meaningful way, it's mostly focused on domestic hot water production. The transcritical CO₂ heat pumps love a very large lift. They excel at making very hot water relative to traditional refrigerants that we've been using for air-to-water heat pumps. But at the same time, that poses a challenge if we try to integrate that a transcritical CO₂ heat pump, say, into a space conditioning, space heating configuration, because the delta T on our system isn't typically large enough to keep a CO₂ heat pump happy.
And so, as Doug mentioned, there's a lot of things that you may have to do to that system to allow it to accept a lower delta T. And with that, you're operating outside of its sweet spot, and so there's an efficiency hit. Co₂ also doesn't tend to perform on the space cooling side as well as refrigerants that we're used to using. And so we're looking at whole life performance, both heating and cooling, and/or domestic hot water production, so it's really about finding the refrigerant that matches the type of load that we're doing. And I think that's where I don't think anybody who's an advocate for R290 or propane heat pumps, I don't think anybody's saying, "Let's throw away CO2 heat pumps." I really think it's about finding the right refrigerant for the right application and then doing so safely.
I'm a huge advocate for finding a pathway for R290, mainly because. From a space conditioning standpoint, especially in cold climates, it performs quite well. So, it hits two buckets at the same time, high performance from an operating standpoint as well as the global warming potential impact. But I'm also a huge fan of CO2 heat pumps. I agree, though, with Doug. Some of the challenges that operating those high pressures are that inherently, the components within the heat pump costs more. There's more robust connections. You typically are going to welded connections inside the apparatus. So, from a manufacturing standpoint, that presents challenges, which then, for my clients, that means that there's a higher price point. Now, some of them are totally willing to do that. They're willing to hit that environmental standard. They are absolutely willing to pay that upfront premium. As I mentioned, we're not trying to find the silver bullet for all solutions. And when we start to think about the ubiquity of equipment from a building type standpoint, not every building type is looking for that high-quality domestic hot water production, like maybe a multifamily project.
We have a lot of rooftop equipment out there in those single-story, two-story either office buildings or warehouse buildings. That's a lot of equipment, and it doesn't pair well when we think about commodity products with the ultrasophisticated high cost and dealing with certain refrigerants. And so I think that's what brings our attention towards finding a family of solutions that can be applied in use types that are really the most appropriate for them. And it ties back to the safety standard to pair with that.
So, for rooftop air handlers, those are direct systems that typically are taking air, heating it, cooling it, throwing it right into the building, and so that presents some safety challenges from a standpoint of if we're using propane and there's a leak within the equipment, or a heat exchanger fails, are we pushing that refrigerant in an unsafe way into the building? And so I think that comes back to a number of the discussion points that we had both at the White House and then for a group that's reconvened as recently as this past week on Monday in California as part of the Codes and Standards Conference of looking at what are the testing standards and R&D really that are needed to make sure that we're finding the safe way in each of these applications to deploy A3 refrigerants.
Ryan Shanley:
And I think maybe that leads us into some questions about what are the current barriers to adopting A3s more widely. A lot of people may not be aware of this, but ASHRAE also has some involvement with the International Standards Organization, which has a corresponding series of standards to ASHRAE's Standard 15, which are the safety standards for refrigerating systems. And the same kind of work is actually going on there currently, and several members of ASHRAE SSPC15 and 34 are involved in those efforts as well. So, outside of North America as well, this is just coming up and starting to be looked at. I noticed that you've mentioned that there's some rollout of R290 systems in Europe, but it's not really all that extensive there either. I think you may have mentioned the last year or two.
Stet Sanborn:
Yeah, really, the driver in Europe has been the FGAS regulations that have pushed the industry in Europe towards propane as a solution in these air-to-water or indirect systems as we are calling them. But there's actually some differences in how Europe goes about regulating refrigerants from a safety standpoint. One of the biggest challenges or differences is that a lot of that safety risk is put on the onus of the designer or installer of that equipment. If I look at the available products on the market in Europe for air-to-water heat pumps, each manufacturer has their own recommendations for spacing requirements, for how close to a window the unit can be, how close to a window well or to a stairwell. And effectively, it says, "Do a paper review, safety review of your design installation and see if you feel like it's a safe installation." That presents some challenges in the market for deployment.
So, as a design professional trying to specify this equipment, having each manufacturer have a different guide for how it gets installed makes it incredibly difficult for us to put a design forward that can be open bid, for instance, to multiple manufacturers. If I'm putting equipment on the roof, what is the spacing between equipment? What's the density of the equipment that I can put on a roof or outdoors adjacent to my building? If that's based on a manufacturer recommendation versus a safety standard, then there's a lot of challenge for us to design something that you could substitute a manufacturer, for instance, in the field for cost concerns. If that meant that every time we did that we had to redesign because now we have a different basis that we're referencing, then it makes it especially challenging for deployment in the US. So, from a design perspective, that's our big challenge.
I don't think that's a hurdle that we can't overcome, but having the standard in place allows us to point and say, "This has been tested. There's a consensus standard based on that spacing requirement or concentration or charge limits." That gives us more certainty in the market as a designer that those solutions have been vetted, and it's a little bit different in how the European standard has been rolled out.
Ryan Shanley:
And referring to the standard specifically for ASHRAE Standard 15.2, Doug, you mentioned, currently does not permit the use of A3 refrigerants at all. So, one of the things I know is being looked at is what can be put in there currently that is generally agreed as a safe refrigerant charge limit for the use of A3s in residential applications. And there's also some proposed research going on to help determine those limits and other data that's really needed in order to be able to update the standards to properly advise on the safe use of these refrigerants and equipment containing them.
Doug Reindl:
And I think Stet mentioned a couple of considerations, and the 15 committee and 15.2 committee have already started really trying to dig into some of these questions. And ultimately, what we're going to need to do is some research to be able to provide decisions that are supported based on some sound research and risk associated with, for example, as Stet mentioned, if we have a unit that's located outdoors, how far does it need to be set back from the residents? What do we do with other equipment that might be located in that area if there's potential ignition sources? In some locations in the northern parts of the US, there's a lot of homes, single-family dwellings that have basements. Those basements have window wells. A lot of these outdoor units are located in close proximity to window wells, so what happens in that situation?
And even in light commercial, stepping aside from 15.2 for a moment, you have other similar low points where, if a leak of refrigerant from a unit can infiltrate those low points, now what hazards are created by that? So there's a number of questions. And, of course, in residential dwellings, not all of these units are located outdoors. Some of them are in interstitial spaces, and that creates a bunch of additional questions. How restrictive do the locations need to be, distances, and what are the hazards associated with that so that these can go in and be operated safely?
And it's going to be a little bit of a different shift too, from not only an installer's point of view but also the homeowner because if those systems are going to find deployment, they're going to be secondary fluid systems. And so now we're going to have to have a hydronic system that will, in cold climates, will use glycol as the working fluid that would go to cooling coils or heating coils for conditioning the space. So, there's going to be some differences in approach with that technology as it finds its way into the US market.
Stet Sanborn:
And it goes back to the discussions that are happening in 15.2 is really trying to take those different application types and carve out what's a pathway. What needs to be validated? What research needs to happen for each one of those types? Because what's come up really consistently across all of our working group meetings is that risk assessment is going to look different for the different application types. And the question about charge limit, the question about spacing, the questions about adjacency to other ignition sources, the recommendation, the result, or the enabling code sections that come out of that are really going to be tailored to that risk profile. And so rather than trying to find a single solution and a charge limit that makes everybody happy, I have a feeling it's going to come out that the different applications are going to have different limits.
And I think that that's going to be born out of the research. And luckily, we've gotten really great lessons learned from the A2L transition, and the partners are already coming together to do that research and to identify the research gaps. And that's everything from fire marshals, fire service, to UL, to ASHRAE, government agencies, even EPA SNAP has a role to play in figuring out this pathway to adopt A3 refrigerants. And so I'd say on the upside, there's a lot of attention and excitement around the market transition, but the most important part is to do it in a way that is transparent, has everybody at the table. And so we don't go down the road, and then, all of a sudden, get push back eight years from now when we're trying to do a code adoption and have fire marshals say, "Hey, we weren't at the table, and we didn't know about this. We're not on board at all."
And so having them at the table early on is going to help identify some of those other market barriers, Ryan, that you mentioned. And it's not just a codes and standard element from an ASHRAE standpoint from 15, but it's the broader impacts and what barriers might occur as we look at this. And so those charge limits, the questions about separation distance, even labeling, is there going to be a new class of labeling that might be required on a building that includes these systems so that first responders are aware that these systems are present? There's a lot of questions that come up even beyond just the performance of the equipment itself.
Ryan Shanley:
So, I know in our meeting at the White House, it came up that there are some applications currently that are using A3s with pretty wide adoption. There's a lot of mention of domestic refrigerators, vending machines. And the commonality between these seem to be that there are low charge limits, factory sealed, so there isn't technician on site inserting and removing refrigerant, having to maintain it in that manner. So, do you think there are other applications that could be looked at as low-hanging fruit, so to speak, where there might be similar kind of characteristics of equipment where there might be able to be quicker adoption of A3s?
Doug Reindl:
So, I would say yes. And you've highlighted a few of them that the producers of equipment like vending machines, they've went in that direction to A3s because they had to meet energy efficiency, increasingly stringent energy efficiency requirements. And really, that was the option for them to do that without drastic changes to their product that would've really increased cost. And so what they have to work within now are some pretty low charge limits, 150 grams in the US, at least, is that threshold currently. So, they've done that. They've produced the products. And if you buy, for example, a home refrigerator now, chances are it's using a hydrocarbon, either R600A, which is isobutane, or R290, which is propane.
But looking at other markets, so in the commercial refrigeration, the supermarket refrigeration, there is increasing interest in deploying technologies that use hydrocarbons. These would be low charge modules that are commonly referred to as monoblocks that would condition whether it be a cooler or freezer type of refrigerated case, and they would reject heat either through a water-cooled loop or air-cooled. The interesting thing, I had a conversation with a designer earlier this week, and it's giving them some tools that they maybe hadn't really had previously to think about. And if you look at supermarket refrigeration, maintaining low space dewpoint temperatures is important for them to minimize things like the parasitic effects of defrosting those cases more frequently when they're in high humidity environments and they have air-cooled monoblocks that provide some space heat where they can now maybe maintain lower space dewpoint temperatures as a form of free reheat that they're getting from the refrigerated cases.
So, I think designers, the ones that are leading on this, are starting to think in different ways and saying, "Okay, rather than take and try to duct this heat outdoors, how can I use it for an express purpose to give me leverage somewhere else in this footprint that we call a supermarket?" So, those discussions are starting right now, and they're finding maybe, hey, I need to think in a different way, and this actually might give me a tool that I didn't have previously.
Stet Sanborn:
I think one of the other things that's really exciting about the conversations that have already started around the use of some of these refrigerants is that there's a really great research opportunity for optimization of charge in how we go about designing heat exchangers, how we go about designing the whole system that becomes, say, a monoblock heat pump. Before the A3 conversation or before that risk factor came in, I would say that the standard refrigeration cycle component sizing has followed a pretty linear improvement process, but there's already been in targeted looking at even heat pump-style water heaters for the residential market. Oak Ridge National Lab has done some really phenomenal research on looking at heater optimizations and different circuiting designs that keep the refrigerant charge down to that 150-gram or lower limit while still providing the enhanced performance that we're looking for. And so there's actually a really great opportunity as we're looking at this to also focus on innovation enhancements and manufacturing enhancements for these designs that actually can allow us to, I would say, get more options even within the reduced charge limits.
And I have a feeling that even as we go through the safety review and if a charge limit is set up, there's a ton of work that can be focused on getting more capacity for heating, or cooling, or domestic hot water production under even within a certain charge limit. So, I think that's something that's often overlooked is that everybody tends to focus on the direct relationship between charge limit and capacity, but realizing that there's actually another opportunity for innovation in optimizing those refrigeration circuits to stay within that bound but get more capacity out of the system. So, this is a great chance where manufacturers and the national labs can collaborate, and with additional funding from the Department of Energy or the White House where we could actually do quite a bit of work to get more options out of reduced charge limits.
And it's not just about a safety enhancement at that point. Anytime that we're looking at refrigerants, whether it's a GWP of seven or 700, less refrigerant, tighter configurations typically are going to meet less leakage through the course of operations of that equipment. And so charge optimization inherently brings environmental benefits when we're looking at just reducing even the potential for leakage during the normal course of operations. And so there's a dual benefit. The putting a cap on the limits also, to a certain extent, is going to drive innovation on just reducing charge overall, which has broader impacts on reducing our climate impact.
Ryan Shanley:
I know a few times we've mentioned transitioning from A1 refrigerants, which were non-flammable to A2Ls, which are lower flammability but still flammable. And I know that transition has taken quite a bit of time. Do you think there's lessons that can be learned from that that could be applied to transitioning to A3s?
Doug Reindl:
Well, I would say yes, but to maybe put a finer point on it, we're still, I would say we haven't really started the transition in terms of field installation of these A2L systems. I mean, they're in their early phases of starting to get equipment that's been designed for utilizing those refrigerants and then rolling out. And really, the long runway was to determine the hazards associated with using these slightly flammable refrigerants that we didn't have in the past to deal with in commercial buildings or residential dwellings and thinking about things like food service. Well, what happens if I have a refrigerant leak in a kitchen where I have open flames? I mean, there's a bunch of issues that we didn't really have to take into account or didn't think hard about necessarily with A1 refrigerants.
And so that process of doing the risk evaluation, doing the flammability testing, a lot of flammability testing was done. AHRI, Oak Ridge, other people that were involved, what are the parameters that we have to implement to ensure that these systems have the opportunity to be safely used in the built environment? And then we have to craft the language for those that would be incorporated into Standard 15, the product safety standards that are published, like the UL standards, then the equipment has to be designed and constructed to meet those safety requirements.
And then the model codes have to adopt them so that they can be either adopted by jurisdictions to say, "Okay, this is what we will allow." And so all of those pieces take time. But I think what the lessons learned in all of the flammability testing, product testing that was done with A2Ls, that gives us a bit of a roadmap for repeating that in A3s. And I think going back to something Stet had mentioned earlier, there are some differences where we're going to have to have infrastructure to do the testing that's more robust than what we had for 2L refrigerants with a higher flammability.
The equipment manufacturers are going to have to have their own infrastructure to be able to develop products and test products and do that safely in their laboratories. And so what we've done with 2Ls provides a roadmap, and it's going to be a little bit different. Going back again to something else Stet had mentioned getting the key stakeholders involved really early is going to help limit speed bumps that we ran into with 2Ls and getting to the stage that we're at right now. So, I think we've learned a lot, and hopefully, we won't repeat the same, I won't call it mistakes, but the same divergence that we had previously and the redirects that we had to come back and address things.
Stet Sanborn:
Yeah, I think just to echo that, when the A2L transition, which I agree with Doug, we are still in. It's not done because, from the design side, we're just now being able to specify equipment with A2L refrigerants and actually find it on the market to put in. But during the A2L beginnings of the transition, that roadmap was being invented, figuring out what tests needed to be done, who needed to be in the room, what the process was even going to look like. That entire roadmap was being invented while it was being driven down, and that inherently brings challenges. I'd say one of the benefits of having that process have already happened is that we've learned things to avoid, things that we don't want to duplicate, but things that were very successful. And there was a number of working groups that actually were very successful that supported the A2L research transitions, and those groups are reconvening as we speak to dive into A3s and then being enhanced with the elements that maybe didn't go so well during the A2L transition.
And so I'm really optimistic. In general, I'm an optimistic person, but I'm generally optimistic that the process can be done safely, and I think it can be done faster than potentially what was done for A2Ls. And we need to. The need for climate action is upon us. We need to find solutions that have whole life carbon benefits. I strongly feel like when I'm in the room and I hear the conversations that are happening that there's a willingness to dive in to do the work and to figure out the safe transition to make it available as an option on the market. And again, it won't be the only option. And that's the important thing to keep in mind, that even as we look at A3s and a transition, there are great solutions on the market today that can help, at least in the interim, reduce our total impact on our designs.
So, although we have an eye on where the target is, action today has impact today, and whether that's decarbonization project on a building or fuel switching, converting to heat pumps that are already available on the market. So, there have been hiccups on the road, but I actually think that looking at the critical mass of super smart people that are diving into this right now across our national labs, from the manufacturer's perspective, even taking lessons learned from their rollout in Europe, and from a manufacturing and testing standpoint, what needs to happen here in the US, there's, I would say, a critical mass amount of attention right now that I think supersedes or even is larger than what the A2L transition had in terms of the pace at which a large collective body want to dive into this really quickly.
Ryan Shanley:
As two of those super smart people who you mentioned, I'd really like to take this opportunity to thank you for having this discussion with me today. I know it's been very informative to me, both this and other conversations we've had. I've learned a lot, and just a really interesting topic, and I think not something people would really think of immediately when you're talking about addressing climate change. My first thought would not be leakage of refrigerants from systems and such. So, I really just want to thank you for taking time from your exceedingly busy schedules to have this discussion with me.
Doug Reindl:
Thanks for inviting us, Ryan. Have a great rest of your day.
Stet Sanborn:
Thanks, Ryan. And I will say that Doug and I are two people of hundreds that are diving in and focusing on this. And I personally just want to give a shout-out. A lot of the folks that are working on these standards committees and doing this work is all volunteer, and you have to give a shout-out to ASHRAE volunteers for diving in and doing the hard work on Standard 15, 15.2, standards group 34, all the standing committees of putting hard work in front of us around decarbonization. But you look around, and there's just an incredible group of people that are doing this work, so my personal shout out and thank you to all the ASHRAE volunteers that are helping to move us forward on decarbonization.
Ryan Shanley:
Agreed. And thank you for reminding me that none of this would be possible without our volunteers, and we're always looking for more.
Stet Sanborn:
Always.
Ryan Shanley:
We'd love for more people to get involved and help take some of the load off of you guys.
Doug Reindl:
Thank you very much.
ASHRAE Journal:
The ASHRAE Journal podcast team is editor, Drew Champlin; managing editor, Kelly Barraza; producer and assistant editor, Allison Hambrick; assistant editor, Sara Omer; associate editor, Tani Palefski; and technical editor, Rebecca Matyasovski. Copyright ASHRAE. The views expressed in this podcast are those of individuals only and not of ASHRAE, its sponsors, or advertisers. Please refer to ashrae.org/podcast for the full disclaimer.