On Sept. 22, representatives of five supermarket chains and four refrigeration contractors discussed their experiences with alternative refrigerants and refrigeration systems as part of a Refrigeration Roundtable in Indianapolis hosted by SN and ContractingBusiness.com (both published by Penton Media, New York). The event, the second such roundtable hosted by the two publications, was sponsored by Hill Phoenix, Conyers, Ga., and Emerson Climate Technologies, Sidney, Ohio. (Click here for a roundtable article  and a transcript  focused on GreenChill and leak reduction.)
The supermarket participants in the roundtable included:
Sam Cantrell, mechanical engineer, Raley’s Supermarkets , West Sacramento, Calif.; George Ronn, senior manager, refrigeration compliance and system controls, Supervalu , Minneapolis; Jerry Stutler, vice president of construction and facility engineering, Sprouts Farmers Market , Phoenix; Steve Hagen, procurement and engineering director, Fresh & Easy Neighborhood Market , El Segundo, Calif.; and Gary Cooper, director of refrigeration, Lowe’s Market , Lubbock, Texas.
The contractor participants included: Bill Almquist, president, Almcoe Refrigeration, Dallas; Bryan Beitler (left), vice president/chief engineer, Source Refrigeration & HVAC, Anaheim, Calif.; Russell Dudan, chief executive officer, Advantage Refrigeration, New Berlin, Wis.; Richard Adkins, sales and marketing, Advantage Refrigeration; and Neil Lansing, owner, Fournier AC & Refrigeration, Jacksonville, Fla. Also participating were Dave Smith, systems specialist, Hill Phoenix, and Tom McFarlane, regional sales manager, West Coast, Hill Phoenix.
The following is an edited transcript of the portion of the Refrigeration Roundtable devoted to alternative refrigerants and systems. Other topics discussed at the roundtable will be covered in future articles and transcript segments in SN and SupermarketNews.com.
CANTRELL: One thing that's kind of interesting to think about is thinking seven, eight years down the road, we could be really caught between a rock and a hard place. The federal cap-and-trade program died, but the California Air Resources Board was right on their tails getting one in place for California. Then right on the tail of that, the Sacramento Municipal Air Quality Management District tried to implement their own in Sacramento County. So I think it's inevitable that someday there's going to be some kind of national carbon cap-and-trade system in place. And with this reduction in leak rates coupled with that cap-and-trade program, we're going to be pinching down the charges on these systems down further and further.
It really seems like we're getting pushed out of DX [direct expansion refrigeration] altogether. I really think that's going to be a tragedy if that happens. There was a move a couple of years ago that everybody was promoting these secondary systems and distributed systems and really was pushing to get away from DX, but you think about the DX technology and all of the body of experience and knowledge about direct expansion refrigeration that exists. I mean, it was invented prior to the car, and that's a huge amount of experience and knowledge that's going out the window. In its place we're getting these new technologies. And who knows? There's a new bogyman, I'm sure, waiting in the wings to appear after the global warming thing has run its course and then we're all going to be moving on to the next thing. I would rather see us getting better at what we know.
HAGEN: I'm very convinced that 10 years from now, every supermarket in America is going to be installing transcritical CO2 systems. I just think that after test after test in Europe and Canada and Australia and around the world, everybody is ending up at that single defining point — that that's the best alternative among all of the other technologies. There are a few people with self-contained propane, but I think transcritical CO2 is going to take the place of other refrigerants because of all of the things that you just mentioned. When they start putting the fines in place, no matter how good you do, you'll have a potentially huge expense and you'll get the higher refrigerant cost.
Sobeys in Canada was saying just the other day that transcritical is all they're doing right now. They've worked with four manufacturers and the first cost to put in a CO2 system and the maintenance on it are lower than their DX system. So I pretty much think we're headed that way.
SN: Would anyone like to comment on how they are finding the phase-out of R-22?
STUTLER: We are converting stores every year, getting rid of the R-22. The supply of R-22 is not a problem today and the price has leveled out; it's stayed pretty stable. And I think if everybody starts to just eliminate the R-22 today — we started a couple of years ago — hopefully we don't run into the same situation we did with R-12. I think everybody waited until the last minute on that one and it just skyrocketed. I think there's going to be an abundance of R-22 sitting around, stockpiles of it, and what we do with it after that, I don't know. I don't have the answer to that.
SN: Are you guys on the contractor side finding any issues with R-22?
ALMQUIST: No. The supply houses will try to scare you into buying some in early spring. It's cyclical. Every year it's kind of the same way. But conversion-wise, a lot of our customers are converting to, I believe, 422D, and other gases.
SN: In terms of converting to HFCs, are people looking at the lowest GWP [Global Warming Potential] gases, like 407A and 407F?
STUTLER: We have converted all of ours to 407F.
HAGEN: The biggest challenge to the new refrigerants is often the compressor manufacturers getting on board with them soon enough to rate their compressors. Guys like Jerry and me and probably some others around the country end up putting in refrigerants that technically void the warranty. Usually you can get the refrigerant manufacturer to pick up that risk but in the meantime you're putting gas in the compressor racks that haven't been specifically designed for them.
There aren’t really any issues there other than you're doing it kind of before the curve, but I think a lot of the people who are really trying to get the GWP down quickly and control the refrigerant are trying the new refrigerants as early as possible.
SN: What HFC is Fresh & Easy using?
HAGEN: We had switched to 407A and now we're using 407F.
BEITLER: We have looked at many conversion opportunities. Each one has got a life of its own. There's a lot of different refrigerants [408As, HB80] out there that have got to be converted, so each one is an engineering event to figure out the right solution. Using refrigerants that have the lowest global warming potential is certainly what we would like to see used. Having minimal changes in the system is the biggest driver, but there are many different flavors of new refrigerants available that our customers have to choose from to get beyond R-22. The greatest challenge is not just to drop it in, but to perform the engineering analysis up front to specify the correct refrigerant type and proper modifications — which might affect efficiency, reliability and leak rates — so that the customer receives the maximum benefit.
HAGEN: Another thing that we look at isn't just the GWP, but it's the TEWI [Total Equivalent Warming Impact]. Some of the advantages of 407A and 407F are that they're proving to be more efficient in operation, so not only are you reducing the GWP on the refrigerant, you're also saving energy, which hasn't always been the case with your refrigerant options. So the latest ones have been a pretty good option because you get a win-win.
RONN: There are also some interesting challenges for larger fleets of R-22 stores, older stores obviously. For those of us who are doing carbon footprinting, R-22 doesn't count in your carbon footprint emissions. So even if you were to take an R-22 system that's leaking 10% and converted it to an HFC that's leaking 1%, whether it's 407F, which is only 1,825 in a global warning number, that 1% leak rate counts against your carbon footprint rate, whereas the 1,000 pounds of R-22 you leak doesn't count.
That has actually changed the dynamic for us to where we are not converting R-22 stores as fast. When we do convert them, we recover the R-22 and use it in our service side and our remodel side as opposed to just all of a sudden going out and starting to change 30, 40 stores a year, because the financial incentive is no longer there to do that.
SN: Are you guys pretty far along in your retrofits away from R-22?
COOPER: Yes, we are, with the emphasis on our store remodels and case change-outs. While the problems associated with oil and system contamination can be an issue, we plan to continue with other rack systems as well. We’re also putting a lot of effort into both condensing units and HVAC systems.
CANTRELL: We stopped doing our conversions about two years ago. We started changing out our R-22 about 15 years ago and less than 5% of our total gas inventories are R-22 now, and we've got a huge stockpile of recovered R-22 at our maintenance facilities because we were anticipating this great shortage of gas and it being a really valuable commodity. It's about $3 a pound cheaper for R-22 than for 404A. And we picked 404A as a gas before any of this global warming nonsense happened. It's frustrating, because 404A is still such a great gas for our systems because of the way it operates — the energy efficiency, the low head heat. We have such a low amount of maintenance in our newer systems with 404A because in that highest-pressure, highest-heat part of the system, you've got this gas that runs so cool. It really does help with the life of the equipment.
We know we're going to have to make a change sooner or later, but I think a lot of chains are kind of waiting to see what this next great gas is going to be that's going to maybe leapfrog you over the HFC issues. HFO-1234yf is looking pretty intriguing if they can get the cost down. Everyone is waiting for somebody to make a move.
SN: Is retrofitting R-22 still a big part of what you contractors are doing?
ALMQUIST: No. That was four years ago, five years ago, and it has virtually stopped now.
SN: But there are still stores that will need to have it done, right?
ALMQUIST: Yes. And on a catastrophic loss, sometimes our customers have a policy that under that scenario, you go ahead and do a conversion.
DUDAN: We often see it when we go into service or store remodels. Typically we are pumping [R-22] out and converting systems to the newer gases for the remodels.
Cascade, Transcritical Systems
SN: Jerry, can you comment on why you decided to test a CO2 cascade system in your platinum GreenChill store, and how it's been going?
STUTLER: It seemed to be the one that made the most sense to us. We looked at the glycol systems and some of the issues people are having with piping with glycol, such as downtime. I know you can go to steel pipe and maybe eliminate some of the downtime, if you had had some leaks on the glycol side with plastic pipe. But CO2 to us just seemed to make more sense. We partnered with Hill Phoenix on this, and we felt that they were well advanced in this system, and along with the addition of microchannel air-cooled condensers, we were able to achieve the platinum level on the GreenChill certification.
It was installed in late April, and as of today, it has operated flawlessly. And if we can get more of the supermarket GreenChill partners to jump on this bandwagon, we would hope that the cost of this system would be reduced. And if it were up to us, all of our stores would be cascade going forward.
SN: That's quite an endorsement. You mentioned microchannel condensers. I heard there were some problems with those.
STUTLER: We had issues with the KRAK microchannel condensers initially. My understanding is [the manufacturers] have corrected that problem, and we are very seriously looking at going back to utilizing KRAK microchannel condensers. But we are not having any issues right now with Heatcraft microchannel condensers.
SN: Does the CO2 system use any regular refrigerant?
STUTLER: It has 235 pounds of HFC refrigerant. Our initial systems had 2,000 pounds of HFC refrigerants. Then when we switched our design to distributed systems, we were anywhere from 600 to 800 pounds of refrigerant. When we went to the cascade CO2 system, we were down to 235 pounds. So it has significantly reduced our HFC stockpile in our store.
SN: The HFC in the cascade system is confined to the motor room — it doesn't go out to the cases, right?
STUTLER: That's correct. SN: So the leak potential is pretty minimal?
STUTLER: That's correct.
HAGEN: We have a CO2 cascade system as well. We have a CO2 glycol secondary system that will be installed in the next few months. And we have a CO2 ammonia system that will be installed early next year that is the first system that won't have any HFCs in the store. It will all be CO2 and ammonia.
We've got some self-contained propane cases in the stores, and I think that's probably the future for small, self-contained cases. I think CO2 is going to be too much of a problem, and propane is more efficient than the 404A, actually. We've got SNAP approval to install about 500 cases, but I want to make sure that what we've got today meets the proposed rules so that I don't put in 500 cases that I have to take out. And I have SNAP approval for a transcritical CO2 system that I hope to put in sometime next year.
I still think that the future is going to end up being transcritical. They're going to overcome the few minor UL issues and I think guys like Hill Phoenix and Kysor — I'm not as familiar with Hussmann and Arneg and where they are on the environmental side — but I think they'll be able to supply the systems pretty readily.
SN: Are contractors up to speed on these newfangled systems?
ALMQUIST: Yes, for secondary, CO2, DX systems, but for the transcritical, I'm just trying to put together the words and trying to even imagine what it might be, so enlighten me.
HAGEN: Transcritical is really just another refrigeration system. The difference is high pressure. It doesn't really work significantly differently. It's just about being able to live with the high pressure.
STUTLER: My short review on transcritical systems is a very small portion of it will be high pressure, and the majority of it will be running at the same pressures that a typical cascade CO2 system will run at. One other point I wanted to make on CO2 — the cost for CO2 today is a dollar per pound as opposed to $10 to $12 a pound for 407F, so there's a huge difference in the cost.
BEITLER: We had the good fortune of installing one of Steve Hagen's cascade CO2 stores, and from a contractor's standpoint, certainly there was a learning curve, and it was a good learning experience. We used different tools, hoses and gauges. We bought a helium leak detection system. There are different techniques to gear up and be ready for. For example, different wall thickness tubing, charging techniques, different operating pressures, fixture piping criteria, etc. These are things that are not terribly unique but do require a different level of training commitment.
SN: How come you bought a helium detector?
BEITLER: With the GreenChill program, you can't use any trace HFC or HCFC gases to inspect for leaks or find leaks.
We believe that that store will probably be the tightest store that we've ever installed. We found leaks that were ounces per year by using the helium technique. So it was a good learning experience for us. The whole store was type K copper.
HAGEN: On the transcritical system, you have stainless steel on the super high pressure side, but type K on the rest.
DUDAN: I have seen helium leak detectors used in manufacturing plants where detection levels are low and time is critical. Helium is a very small molecule and will expose very small leaks. We have not seen it used yet in the construction of supermarkets, but the technology is available and proven.
SN: Transcritical works better in cold climates like Canada where Sobeys is. Is that a factor for you, Steve?
HAGEN: It's not going to be very applicable in a desert. In San Francisco, you're going to save energy over a DX system. In Atlanta you pay a small premium in energy. I think some of that will probably get worked out to make it more efficient over time. You may always have some things you have to do in desert climates, like using cascade to keep the pressures down.
SN: The secondary systems with glycol and CO2, does anybody else have any experience with those compared to DX? George?
RONN: We had, of course, our store that won the first platinum GreenChill award a couple of years ago, the secondary CO2, secondary glycol for medium-temp, with the compact chiller system. Coming out of that, we standardized on a distributed DX low-temp system with medium-temp glycol, which is our standard for new full-size stores. We don't build new conventional DX any more.
In the compact Save-A-Lot stores, we haven't done that. They still use a conventional DX system. We have a store in California under construction now that's going to be our first ammonia primary system, with secondary CO2 and secondary glycol. So we'll see how that goes.
ADKINS: We're kind of seeing the same trend here in the Midwest with a couple of our different customers utilizing medium-temp glycol throughout the whole store, with ABS plastics.
SN: What about the low temp?
ADKINS: Just DX 404A.
ALMQUIST: We're installing a national wholesale grocer’s facility now in the Dallas area, the same scenario — glycol medium-temp with copper piping, and DX low-temp with loop piping on the liquid line but individual suctions for each system, so kind of a hybrid of a hybrid.
SN: So glycol is getting more common for medium-temp and I guess for low-temp some people are using CO2, though it’s not that common. There’s still a lot of DX for the low temp.
ADKINS: We're finding some of our customers have been changing out most of their fresh meat service cases just to glycol. I suspect that is for numerous reasons, but one is the freshness and the integrity of the product that they achieve as much as the energy.
CANTRELL: We've got one secondary system that's 404A primary and liquid CO2 and glycol secondary. It could be that we just had inexperienced contractors, it could be a misapplication, but we didn't have a very positive experience with it at all. We ended up with a system that was considerably more expensive and has a significantly higher service cost and uses about 3% more energy. So really there's no incentive in my mind for pursuing this. I understand it was a good experience to get our minds around what was involved if we were forced into it — if DX just becomes cost-prohibitive because of regulations or something.
I'm not really sure what the motivation is for secondary technologies — if it's purely just bragging rights or what it is that's pushing so much of the industry into that.
STUTLER: There are a couple of incentives there. If your company is looking to lower your carbon footprint and get rid of the HFCs, that's one. And the second one that I noted earlier is the cost on the CO2 side; I'm not sure about the glycol side. If I dump 100 pounds of CO2, that's $100 worth of CO2 as opposed to $1,200 worth of refrigerant.
HAGEN: I think literally for us, it's about testing what's available so that when 404 or 407 is $80 a pound we know which way we want to go, instead of losing millions of dollars while we're trying to figure out where we're going.
We're doing a glycol store, and to be honest, I'm not sure why. You always pay a penalty in energy for glycol. So if you do one, you're never going to expect it to have less energy than a DX store. It's gotten closer and closer and closer, but that 3% to 5% appears to be about as good as it's going to get unless somebody comes up with some magical liquid that's going to do it. And it never works even close for low temps. So I think glycol is out. In fact in California, pretty soon you're not going to be able to use glycol as a secondary at all. Even with the current code, about 40% of the cities are using the “stretch goals,” which are going to eliminate glycol in California because of the energy.
ALMQUIST: The point I was wanting to ask you guys on the supermarket side: If you're doing new technology, would you have a tendency to negotiate those jobs with the contractor or would you say, hey, we're putting it in, we know you haven't ever done it before but here's the bid package, or would it be more a negotiated deal?
STUTLER: Hill Phoenix manufactured our cascade system, has also serviced parts. I wanted a complete package. I wanted them to own it. It's theirs. They engineered it. They built it. They installed it. They're going to own it. And we took an extended warranty on that particular project. I would not bid this project out unless I had a group of refrigeration contractors that had a successful experience installing this type of system.
SN: George and Steve, you mentioned ammonia as a primary refrigerant for a system that had CO2 as a secondary refrigerant. What are the issues with ammonia?
RONN: Well, I think one of the big issues is to make sure the local authorities understand the ammonia system because the charges are relatively small overall. Of course, you always have the possibility of air inversion or fog that's going to hold the odor if you have a leak, but the amount of ammonia involved is not enough to be considered toxic (unless in a confined space). So you probably need to let your neighbors know that these are ammonia systems, and in the event of a leak, they'll smell the ammonia. But it's not like a railroad incident where there is a tank car leak and you clear out an entire city block or something. You're not talking toxicity or even odor to that level. But in most instances, even if there were a leak, ammonia is lighter than air anyway, so it's going to rise.
STUTLER: You may have seven or eight of these individual modules and have maybe 60, 70 pounds of ammonia up on your roof, but the likelihood of all of that leaking at one time is like winning the lottery probably. So you may have one module leak and that's only nine pounds of ammonia.
HAGEN: The ammonia system has less capacity because we added glass doors to the design, and it's got about 48 pounds of ammonia, but it's on the roof. If there is a system issue that causes it to shut down or go over pressure, it dumps the ammonia into a water tank, so you don't get a release. It's only released if a line breaks, and then you're looking at four different systems that each have 12 pounds, and the gas is going to go up. And when you think about all of the air between you and anybody else, it's going to disperse. The concern, of course, with ammonia is that when you use ammonia to clean your house, it's a 1% solution, and ammonia you use in refrigeration is a 99% solution, so you can imagine how much stronger that smell is. You never have to worry where the leak is. You can find it really quickly.
ADKINS: Being an ammonia contractor, we deal with systems that have over 10,000 pounds of anhydrous ammonia. Anything over 10,000 is highly regulated by OSHA and EPA, which requires PSM [Process Safety Management] and other programs. It's a refrigerant that's been used for years. It was one of the very first refrigerants. We've made a full circle. In coming back to it now, I think it's going to be a great refrigerant for a supermarket application.
HAGEN: The other thing that you run into is there are specific codes and requirements regarding ammonia in different applications. When you limit the charge, you limit other safety requirements that a higher volume of ammonia would have; at a warehouse, according to code, you have to have 24-hour service on-site when you have over certain quantities. With the stores, depending on the environment, it's a lower amount. So part of what the compact chiller does is it eliminates the potential of having a lot of ammonia go out, but it also eliminates a lot of the safety issues that you might run into if you had a higher percentage.
SN: So most of the ammonia is on the roof?
HAGEN: It's all on the roof. It's all used on the high side from the roof to the compressor.
SN: Would you not smell it in the store if it leaked?
HAGEN: It will go up.
RONN: You could have an air inversion. That's not uncommon in some of the valleys where you've got mountains around it, or a coastal fog situation which holds the odor down, but in most cases, it's just going to go up.
STUTLER: Once again, you're talking probably nine pounds, and that's going to dissipate quickly.
SN: So Jerry, are you looking at ammonia?
STUTLER: We are considering ammonia, and we are looking at some other alternative systems that I can't really discuss right now.
SN: How is the refrigeration equipment different for ammonia than it would be for a normal refrigerant?
RONN: It's just the components that are different — steel as opposed to copper and that kind of stuff.
SN: Going out to the cases you would have CO2?
RONN: CO2 or glycol, some other transfer medium.
SN: I would imagine we're going to see a lot of changes in these systems. Sam, I know you think DX is still the tried and true process, though, right?
CANTRELL: I do think that natural refrigerants are where we end up ultimately, and we've looked into doing an ammonia/CO2 system. We had a design pretty much penciled out. It was going to be an adaptation of our system. But there are just a few things that are hard to get over with transcritical CO2.
Having a trapped column of liquid CO2 can turn a section of pipe into a pipe bomb inside your store. With ammonia, all it takes is one busybody neighbor to start raising hell about health problems and trying to take you to court because they're saying that their kids are having problems because there's ammonia in the air.
Even if you do get a small leak on the roof and the wind blows just right, you have one person around to smell it, you would think their world is coming to an end. Even though it's a very small volume, it's very unpleasant.
It's something you have to get over. There's a stigma to it. Once you get over it, you probably found out that there wasn't really much to fear in the first place. But it’s not just about me getting over it. It's getting our whole company past those “what if” situations; it's not easy.
HAGEN: Interestingly enough, there’s housing built up around dairy plants all around the country, and most of the dairy plants have ammonia in them. I used to work for a company that had a dairy plant that ultimately ended up in the city, and they continued to operate that plant. It's since shut down, but for years and years, there were houses within a hundred feet of the edge of the property; they had leaks and the people were just used to the smell. Once or twice in 20 years they had some major leaks, and the fire department showed up, which happens with ammonia quite often. But there was never an incident in the neighborhood where anything [serious] happened.
ADKINS: Ammonia has been the refrigerant for most industrial applications and RV refrigerators for years. A lot of people don't realize that ammonia is the refrigerant used in those refrigerators.
SN: Steve, what got you involved with propane?
HAGEN: In Australia I noticed the self-contained cases that they were using and were used through most of Europe are propane-based. Propane used to be a common refrigerant used in refrigerators and in travel trailers, where the propane that heats the stove also cools the refrigerator. People talk about the safety concern. It is definitely more flammable than the other refrigerants but almost everybody in America has a five-gallon container on their barbecue grill with propane.
My other thought process was if you walk into any Wal-Mart or a Target, and you walk to the camping section, they have 50, 100 14.1-ounce cans in a self-contained case. The ones we use have 4.1 ounces. So I thought in terms of safety, it's safe and it's more energy efficient than the 404A in cases. So for me it's a small amount. It's split over several cases. It's only 4 ounces each. The potential for any type of accident is very limited in that application. I'm not sure that I would say, OK, let's put 200 pounds on the roof to run a CO2 system yet, but from the perspective of small self-contained system, it seems to me to be a viable alternative.
STUTLER: The only thing I have to say about propane and safety in comparing this to the propane on the shelves in Wal-Mart — you typically don't have a refrigeration contractor with a torch running around on the shelves of a Wal-Mart, but you may have one at a case that has propane in it. And if you've ever seen a video of 1 pound of propane go up, it's pretty devastating.
SN: Steve, these are self-contained cases. Do you have many self-contained cases in a store compared to cases that are linked up to the refrigeration system?
HAGEN: Five, so not very many. It was just the right application for a retrofit that we did, and then we maintained that design because it's a lower-cost design and a more energy-efficient design.
SN: They're all coffin cases?
HAGEN: Yes, they're all coffin cases with doors.
SN: So it makes sense for self-contained coffin cases but not self-contained upright cases?
HAGEN: The loads are a lot greater on the bigger cases, and these are freezers, so if they were upright freezers, it wouldn't make a lot of sense. There are people in Europe today doing self-contained upright propane cases. In a store they might have 50 cases but still in 4-ounce sections. And in those cases — to Jerry's point — they're using a little bit different enclosure. They've come up with some special horizontal compressors, and they're making a much stronger enclosure, so the potential would be lower for something to happen. But you definitely have to train technicians about what's there because they tend to put torches on things they shouldn't.
ALMQUIST: I'm not concerned with torches. I'm concerned with pressure switches that have contact. When they make a little spark, that's what's going to be a problem when you have a leak and it's the right concentration in that enclosed area. I'm just surmising. That's how you start a gas grill, with a small spark.
SN: Europe and perhaps Australia seem to be ahead of the curve. What have you guys learned from what they're doing there? Is that where we're getting our best ideas?
HAGEN: Wherever there's legislation and taxes, you have a lot more ingenuity and innovation. That's my take.
ALMQUIST: I think from a technology standpoint that is true, but let me share with you a vignette. I was on a street in Florence, Italy, and I was standing there eating my morning gelato right after I had my morning espresso, and I was watching five AC technicians trying to change a mini-split system in a storefront. They have the same technician issues we do. Let's just say that. There were five of them trying to change a Mitsubishi mini-split system. So they have the same issues. Fantastic technology, fantastic innovation and they still have technician issues.
SN: I don't know if anybody has heard of geothermal technology being used in supermarkets?
BEITLER: We have just heard of an isolated case where well water is being used for cooling coils but there's not much in any larger applications. We've seen geothermal in heat pumps, air conditioning applications, some central plants, but not in supermarkets.
HAGEN: We've looked at [geothermal systems] because it's one of those things that's kind of cool to do. But every time we've looked at it and we've looked at a site where we might to do it and we talked to people about what kind of a geothermal area it was and what the costs might be to drill, it's just been so far away from being something that you would say you would ever do; it just hasn't made sense.
SN: Is anyone looking at HFOs as an alternative refrigerant?
RONN: HFO-1234yf is only approved for automobile air conditioners.
STUTLER: It's cost prohibitive right now, but maybe with a low-HFC or low-refrigerant system such as cascade, with a few pounds of it, that may be the alternative to look at.
RONN: Its energy curve more closely matches R-134A, which only works in a medium-temperature application and as a primarily refrigerant on a secondary system. You can't really use it for a frozen-food application.
SN: Are these alternative systems like CO2, cascade and secondary proving to be more energy efficient than conventional systems?
HAGEN: The CO2 cascade system is about 5% more efficient than our current DX system design. I'm going to guess that our ammonia system will be in the same range in terms of savings. The compact chiller CO2 glycol system I'm going to guess is probably going to be the same as other people had — a few percentage points higher in energy cost.
SN: Jerry, is your cascade system more efficient than a conventional system?
STUTLER: We're experiencing higher energy consumption on this. But we're still in the test phase. We are still trying to come up with a perfect comparison with some of our other systems, so I'm not going to give you a percentage at this time. However, what I will say on that point is that even if you're 5% higher, with the reduction of the HFC refrigerant that you pulled out of the store, the carbon footprint reduction far outweighs the energy increase.
SN: In determining the total cost of ownership, would a cascade system be more expensive over the long term than conventional systems?
STUTLER: The up-front cost is more expensive today. As I mentioned earlier, we would hope that other supermarkets would get on board and hopefully bring this cost down. I think it's hard to put a return on your investment on this. You could put in a complete DX system with 2,000 pounds of 404A or 407A or 407F, and maybe never leak or not leak 100 pounds in 10 years. You don't know. I mean, it's just a roll of the dice. But we all know that we have leaks quite often, and I believe over time that there's going to be a payback on the system with the reduction of refrigerant.
SN: What do you expect the payback to be?
STUTLER: Michael, it's so hard to put a number to it, it really is. Right now, the payback is that we have reduced our carbon footprint tremendously from a typical DX system. I would hope that there isn't a payback because I would hope that I never leak any refrigerant from a conventional DX system. But once again, it's just hard to put a number to it. It's a roll of the dice. You just don't know.
HAGEN: The truth is there is really a significant increase in cost today. But as you heard from Sobeys at the FMI Energy Conference, they're buying enough [transcritical] systems now and have enough suppliers involved and it's pre-dialed in. They have the parts available. They're buying enough that the cost is actually lower than if they bought a DX system; they're not even comparing them anymore.
In terms of maintenance, our cascade system was not the most flawless or problem-free installation to start with. Part of that is relative to the control systems that we use. We just changed the pressure on a couple of valves, and I don't think we've had a service call in the store in 90 days. So now it's running the way everybody else is talking about in the rest of the world. CO2 systems are really proving to be very reliable and almost bulletproof in their normal operation.
SN: Who else besides George is looking at distributed systems as an alternative to conventional DX?
COOPER: I think the best solution for us is distributed DX systems with the use of medium-temp glycol secondary systems as store design permits. We are also going to give more consideration to CO2 as an alternative to HFCs and while there are some design considerations it appears to at least have a stable future.
ALMQUIST: Yes, a distributed system is becoming the standard, a distributed system with loop piping or traditional branch circuit piping.
BEITLER: I guess I've seen it kind of go both ways. I've seen some customers that went distributed that have gone back the other way, and I've seen traditional racks move to distributed. To save on construction costs, they put equipment closer to where the loads are. As a servicing contractor, equipment on the sales floor is sometimes a little problematic, keeping your tools from walking away and those kinds of things. It is also complicates the service process by having key components on the roof and not part of the indoor equipment package.
SN: Distributed systems cut leaks, don’t they?
STUTLER: It reduces the amount of refrigerant, but it's going to increase the amount of equipment. Now, I can see the larger conventional stores, the 60,000-, 75,000-, 100,000-square-foot stores maybe straying away from the distributed, but for our footprint, and I'm speaking for Steve here a little bit, Fresh & Easy, I think distributed is a simple answer.
HAGEN: Our stores are only 15,000 square feet and we still only have one rack but we put it on a mezzanine on top of the walk-in [freezer] in the center of the store. You almost can't get any more distributed than that, so we're kind of lucky in that it works out fine. But we did change from the mezzanine and put it outside but we put it back in the store because while putting it outside got rid of the mezzanine it also increased the run of the refrigerant and increased the refrigerant capacity. So that's our version of a distributed system; we don't have five small systems out on the sales floor, which might have a little bit less refrigerant but be a lot more difficult to work on.
SN: Jerry, you have distributed in your stores?
STUTLER: Yes, we're typically a 25,000-square-foot store, and the way our refrigerated merchandise and equipment is laid out is pretty much on the perimeter of the store with less in the front. So we have one rack sitting over on one side of the store, one rack on the other side of the store; both of these racks sit on top of walk-in coolers.
RONN: In our [distributed] design, we have probably three low distributed units that would be in the backroom somewhere, including one near the bakery or deli area to take care of those loads; and we have one probably on top of the meat, one on top of the walk-in boxes to take care of the frozen food in the Center Store area and then one tucked away somewhere on the other side of the store.
SN: What about Raley's — do you have distributed systems?
CANTRELL: No. It may seem a little bit cynical, and it's not that we're not innovative or progressive in our design. We developed our own refrigeration system that we build in-house about 15 years ago, and it's gone through a lot of revisions and we've tried different versions of it. We are willing to try new technologies as they emerge, but they've got to make sense.
Maybe there are store formats where distributed systems make sense. But for us, what you're really afraid of with refrigerant leaks is gas that leaves the system, and gas leaves the system through potential leak points. If you triple or quadruple the amount of moving parts in a store with distributed systems and you've tripled or quadrupled the amount of leak points. So having multiple condensers, and multiple machine rooms, it just didn't make sense for us.
Our system is different than almost anybody else is using. You can get our system from Hill Phoenix. It's not that it's unattainable or exclusive, but few people are willing to try it. It's an open drive system. It has big industrial compressors and a single pipe loop. But we start out already with a system charged about 25% less than conventional racks. Couple that with saving 10% to 20% on energy and 30% or more savings on service, and it's really hard for us to give that up to try something unproven.
SN: Farm Fresh has that, right?
CANTRELL: Farm Fresh has it, and Big Y has some. So it's not that we're just stubborn, and this is the way we've always done it. I'm eager for the day that we get a chance to try a natural refrigerant store and we'll definitely be game for it. But as I said before, we were only able to reduce our charge about 30% with a secondary system. It wasn't a huge success for service costs. It wasn't a success at all for energy. It's just we're very infatuated with the system we've got and we've been pitting it against whatever challengers we can get data on, and we haven't found anything that will top it. So that's kind of where we're at.