Appliance Design - March 2009 - (Page 36)

INSULATION -6.4 percent volume change for the AFA-G2 foam; and -17.3 percent for the HFC-134a foam. The k-factor for the three foams was measured over five temperature ranges, with the lowest 18 DegF and the highest 104 DegF. The two AFA foams showed comparable k-factor performance with HFC-134a, with the exception of the coldest temperature (18 DegF), where the AFA-G1 performance was worse than both the AFA-G2 and the HFC-134a. In tests involving two different foam formulations, the two experimental liquid blowing agents, AFA-L1 and AFA-L2, were compared against HCFC-141b, HFC-245fa, and an 80/20 blend of cyclopentane and isopentane. In the Formulation 1 test, all five foams showed similar blowing efficiency, as indicated by free rise density. Because of the lower density and lower functionality polyol makeup, all the foams showed significant volume change. AFA-L2 expanded the most at 41.8 percent volume change, and AFA-L1 expanded the least at 18.6 percent volume change, roughly 6 percent to 8 percent less than the other three foams. The initial k-factor results for this formulation with the liquid blowing agents showed that both AFA-L1 and AFA-L2 exhibited significantly better k-factor than HCFC-141b, especially at the cold-temperature to room-temperature test conditions. AFA-L1 exhibited a better k-factor than HFC-245fa over all test temperatures; AFA-L2 also performed better than HFC-245fa, but the gap was less, especially at the colder test temperatures. Both of the experimental liquid blowing agents performed much better than the cyclo/isopentane foam. In the Formulation 2 test, AFA-L1 alone was compared against the HCFC-141b, HFC-245fa, and cyclo-isopentane. As with Formulation 1 foams, AFA-L1 showed similar blowing efficiency to HCFC-141b, HFC-245fa, and cyclo/ isopentane. Due to the higher density and different polyol composition of this system versus Formulation 1, all the blowing agents tested gave similar and acceptable dimensional stability performance. AFA-L1 exhibited similar k-factor performance to HCFC-141b over all the temperatures tested and performed slightly better than HFC-245fa. However, the differences were much less than with Formulation 1. Also, as with Formulation 1, AFA-L1 performed significantly better than the cyclo/isopentane foam. The conclusions drawn from the testing of the new low-GWP blowing agents suggest that AFA-G1, and to a lesser extent AFA-G2, can potentially compete with HFC-134a in terms of solubility in polyol, dimensional stability, and k-factor, although AFA-G1 seems to perform less well at very cold temperatures. The more interesting results were found on the new low-GWP liquid blowing agent candidates for replacing HFC-245fa. AFA-L1 displayed a similar blowing efficiency and dimensional stability and a significant advantage on k-factor compared to hydrocarbons. ? ? DuPont Development of a Novel Foam Expansion Agent for Polyurethane Foams, by Mark L. Robin, Gary Loh, and Joseph Creazzo, DuPont Fluoroproducts, Wilmington, Del. The regulatory mandated phaseout of HCFC-141b as a foam expansion (blowing) agent for polyurethane foams required the development of Third Generation foam expansion agents such as HFCs and hydrocarbons. 36 applianceDESIGN March 2009 AD03094FOAM.indd 1 2/13/09 10:28:16 AM www.applianceDESIGN.com http://www.ecomatesystems.com http://www.ecomatesystems.com http://www.appliancedesign.com

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Appliance Design - March 2009 Contents Editorial Shipments/Forecasts News Watch Transmitting Power Wirelessly Promises to Reduce the Ever-Growing Tangle of Cords and Cables Found in the Modern Home. There Are Different Technological Approaches for Achieving this Goal, and Some Are Already on the Market. Electrochemical Capacitors Can Provide an Extra Peak-Power Boost in Battery-Operated Appliances, Allowing Product Designs to Have Smaller Battery Packs. Metallic Foams Put the Properties of Metals into Lightweight Packages. Applications for this Emerging Technology Include Gas Burners, Heat Exchangers, and Electronics Housings. Hall-Effect Switches Are Compact and Provide a High Degree of Reliability and Durability as They Virtually Eliminate Mechanical Wear, Shock, and Contact Oxidation. Blowing Agents for Polyurethane Foam Insulation Face Increased Scrutiny Due to Global Warming Concerns, but Alternatives with Lower GWP Values May Provide Solutions to Meet These Challenges. Design Marts Association Report: AHAM Advertisers' Index

Appliance Design - March 2009

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