Abstract
HFC-245fa (1,1,1,3,3-pentafluoropropane) has been under development by AlliedSignal since 1994 as a potential replacement for HCFC-141b in blowing agent applications. During 1996, a great deal of work took place that compared the physical properties of appliance foams prepared with HFC-245fa versus other blowing agents. During 1997, it is anticipated that ongoing performance optimization work will enable appliance manufacturers to conduct plant trials using HFC-245fa as the blowing agent.
The domestic refrigerator appliance industry is under a time constraint to make a transition to a third generation blowing agent, such as HFC-245fa, by January 2003. In addition to the phase out of HCFCs, Department of Energy regulations will mandate an increase in the energy efficiency of refrigerators effective July 1, 2001. Needless to say, the development time for the appliance industry is short.
Further optimization studies will enhance the insulation value and physical properties of foams blown with HFC-245fa. Development work is also being performed that examines the overall system, that is, the interaction of HFC-245fa foam blown into the walls of a refrigerator. This paper will discuss the results of a freeze stable density study using HCFC-141b and HFC-245fa as blowing agents. Results from a surfactant screening study that examines flowability will be reviewed. In addition, modeling of blowing agent diffusion into a refrigerator will be discussed. This work is part of a continuing effort by AlliedSignal to develop a blowing agent replacement for HCFC-141b that meets the needs of our customers well into the future.
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