Estimate the R-values for a 2-inch-thick fiberglass board and a 1-inch-thick polyurethane foam layer. Then compare their respective conductivity-times-density products if the density for fiberglass is 50 kg/m3 and the density of polyurethane is 30 kg/m3. Use the units given in Figure 1.27.
GIVEN
2-inch-thick fiberglass board, density = 50 kg/m3
1-inch-thick polyurethane, density = 30 kg/m3
ASSUMPTIONS
(a) One-dimensional, steady conduction