Development of high-performance composite foam insulation with vacuum insulation cores

Development of a high-performance thermal insulation (thermal resistance or R-value per inch of R-12 h·ft²·°F/Btu·in. or greater), with twice the thermal resistance of state-of-the-art commercial insulation materials ( R6/inch for foam insulation), promises a transformational impact in the area of building insulation. In 2010 in the United States, the building envelope-related primary energy consumption was 15.6 quads, of which 5.75 quads were because of opaque wall and roof sections; the total U.S. consumption (building, industrial and transportation) was 98 quadrillion Btus (98 quads). In other words, the wall and roof contribution was almost 6% of the entire United States primary energy consumption. Building energy modeling analyses have shown that adding insulation to increase the R-value of the external walls of residential buildings by R10-20 (h·ft2·°F/Btu) can yield savings of 38% to 50% in wall-generated heating and cooling loads. Adding R20 will require substantial thicknesses of current commercial insulation materials, often requiring significant (and sometimes cost prohibitive) alterations to existing buildings. This article describes the development of a next-generation composite insulation with a target thermal resistance of R25 for a 2 in. thick board (R12/in. or higher). The composite insulation will contain vacuum insulation cores, which are nominally R35-40/in., encapsulated in polyisocyanurate (PIR) foam. A recently developed variant of vacuum insulation, called modified atmosphere insulation (MAI), was used in this research. Some background information on the thermal performance and distinguishing features of MAI has been provided. Technical details of the composite insulation development and manufacturing as well as laboratory evaluation of prototype insulation boards are presented.