The Effect of Blowing Agent on Refrigerator/Freezer TEWI

When evaluating alternative blowing agents from a global environmental standpoint, it is appropriate to use a total environmental warming impact (TEWI) analysis that includes both direct and indirect environmental warming effects. Parameters that relate to the foam blowing agent and TEWI of a refrigerator include initial thermal conductivity and resulting product energy consumption, rate of increase in product energy consumption due to aging of the foam, the direct global warming potential (GWP) of the blowing agent and the amount of blowing agent that is released to the atmosphere. Energy consumption and foam aging data are available from cooperative studies conducted by members of the Appliance Research Consortium. Information regarding the direct GWP of alternative blowing agents is also known. However, there is only limited information available regarding the rate and to what extent the blowing agent escapes from the foam and enters the atmosphere. In this paper TEWI calculations are presented, using available data and simplifying assumptions and estimates in order to provide comparisons between products foamed with different blowing agents. Calculations indicate that for countries with a significant portion of electricity produced from fossil fuels, there is little difference in TEWI when comparing products foamed with HFCs to those foamed with hydrocarbons.