ASHRAE Journal - December 2010 - 18

q&a
reduce the carbon footprint of GWP by going from 134a to an XP10 option. Whether that technology transition takes hold in the U.S. remains to be seen. If it goes well in Europe, when would XP10 be available in the U.S.? Diane: That’s a tough question. It depends on a lot of factors, but we are seeing interest in lower GWP refrigerant options for stationary applications in the U.S., and we have several partners looking at lower GWP refrigerant options under development programs. The timing for XP10 will be based on overall interest in the refrigerant for the equipment technology they are developing. Based on what we are observing, it would be after 2012 that it would come to the U.S. Eric: We previously indicated that we are looking to do an initial market introduction of XP10 in the 2012 – 2013 timeframe. One thing that’s clear is that because XP10 is based on HFO-1234yf, our ability to expand market availability will be directly related to how quickly we’re able to ramp up production on 1234yf. The mobile AC market is the first market adopting an HFO and it will receive first priority. We expect to be able to initially offer XP10 for other applications in the 2012 – 2013 timeframe. We anticipate that it will be several years after that before we’ll be in a position to offer XP10 on a broad basis. What are its advantages in comparison to 134a? Eric: Under direct global warming, we understand clearly how this would compare with 134a, and that’s why Diane Picho we’re engaged in a lot of the field test work first in the supermarket application. As we continue development, we’ll better understand the total life-cycle impact in different applications. In Europe, there’s already a trend from R-404A direct expansion technology to a hybrid approach using R-134a in medium temp and CO2 in low temp, and they’re finding that offers substantial improvement in energy efficiency and reduced GWP. So if you then go to the next step where you would replace 134a with XP10, and you run those numbers, the supermarket could reduce its direct GWP for the total system by almost 90% and their TEWI (total equivalent warming impact) by about 50%. We’re just really starting to sharpen our pencil on these type analyses. The more applications we test, the better we’ll be able to understand the comparison to 134a. What is involved in introducing a new class of refrigerants? Diane: Take the example of the HFO-1234yf. The initial need for the automotive application was in the 2004 – 2005 timeframe, so that process took six years and there was work done by refrigerant manufacturers like DuPont before getting to that point. The key challenge is that you have to
18 ASHRAE Journal

look at a balance of properties from a safety perspective, from an environmental perspective, from a performance perspective and an overall cost perspective for the various refrigerant options. Going through all the testing and evaluations takes a lot of time. The toxicity testing, for example, is a several-year journey and a very significant investment for a company. In addition to the work we do in our lab, we need to evaluate the refrigerant system with partners throughout the value chain. And in the case of HFO-1234yf, which is mildly flammable, there are a host of risk assessments. So as I said, Opteon™ XP10 is a lower GWP option that is nonflammable. However, there is still a lot of work to be done relative to working with various partners to evaluate for use in specific applications. This is a significant investment, not only for the refrigerant producers but also the partners. Eric: The criteria or requirements have only continued to become more demanding as we’ve evolved from CFCs to HCFCs to HFCs and now HFOs. With each step along the way, the research gets a little bit more challenging because we add more criteria to the list. Before, when we had to worry about ozone depletion, it was a little easier to find new solutions. Now we’re adding GWP to the list, which narrows the field even further. The periodic table is a finite thing and there are only so many combinations of molecules. That’s why we’re so excited about XP10 because we really think we hit upon a sweet spot with this product. What is driving its development? Diane: I think Eric did a good job Eric Youngdale articulating the main drivers on the European perspective and supermarket application. They are looking at cascade systems with the use of 134a in medium temp and CO2 in low temp, which is driving further optimization of the system looking at low GWP options for the medium temp. That’s where Opteon™ XP10 is a good offering to meet those objectives for those applications. Eric: Another comment that ties into the question is that there’s no single perfect refrigerant that’s going to work in every application. There are places where CO2 makes sense, and there are places where other natural fluids make sense, like ammonia and hydrocarbons, and those are already gaining presence in some applications. And there have been a lot of applications where HFCs have offered the optimal balance of properties in terms of safety, cost, performance and environmental impact. So the game hasn’t changed and this is going to continue. The challenge is to continue to find those products that have the optimal balance of properties for specific applications. Based on the testing we’ve done and the market discussions and dialog we’ve had, Opteon™ XP10 offers the optimal balance of properties for a lot of the supermarket applications in Europe. I think as we go out into the marketplace and talk to more people and do more testing,
ashrae.org December 2010

ASHRAE Journal - December 2010

Table of Contents for the Digital Edition of ASHRAE Journal - December 2010