Novel Rigid Polyurethane Foam Systems in Support of CFC Reduction/Elimination and Energy Conservation Standards

The U.S. domestic refrigerator appliance industry is currently facing two challenges. It has to reduce its use of CFC's, including CFC-11, which endows the insulating foam used in the appliances with excellent energy saving properties whilst it has to meet increasingly stringent energy standards culminating in the 1993 D.O.E. measures. Significant reductions in CFC-11 use without any change in energy consumption can be achieved with novel foam systems which are now in commercial use. Systems have also been developed, and are undergoing application testing, where the CFC-11 is replaced by either HFA 123 or HFA 141b. Similar thermal conductivities are achieved to those for systems based on CFC-11. The options available to help meet the 1993 DOE standards are discussed. These include increased wall thickness and the incorporation of vacuum panels. The characteristics of optimised foam systems for use in these options are presented.