Download Thermal Properties of Materials: Conductivities and Insulation Values and more Lecture notes Experimental Techniques in PDF only on Docsity! Thermal Considerations 01/17/2008 Lecture 4 1 Winter 2011 UCSD: Physics 121; 2011 2 Winter 2011 UCSD: Physics 121; 2011 3 Winter 2011 UCSD: Physics 121; 2011 4 Material κ (W m-1 K-1) comments Silver 422 room T metals feel cold Copper 391 great for pulling away heat Gold 295 Aluminum 205 Stainless Steel 10–25 why cookware uses S.S. Glass, Concrete,Wood 0.5–3 buildings Many Plastics ~0.4 room T plastics feel warm G-10 fiberglass 0.29 strongest insulator choice Stagnant Air 0.024 but usually moving… Styrofoam 0.01–0.03 can be better than air! Thermal Considerations 01/17/2008 Lecture 4 2 Winter 2011 UCSD: Physics 121; 2011 5 Winter 2011 UCSD: Physics 121; 2011 6 Winter 2011 UCSD: Physics 121; 2011 7 Winter 2011 UCSD: Physics 121; 2011 8 • Note that these examples use the non-SI definition and are per inch. Vacuum insulated panel has the highest R-value of (approximately 45 in English units) for flat, Aerogel has the next highest R-value 10, followed by isocyanurate and phenolic foam insulations with, 8.3 and 7, respectively. They are followed closely by polyurethane and polystyrene insulation at roughly R– 6 and R–5. Loose cellulose, fiberglass both blown and in batts, and rock wool both blown and in batts all possess an R-value of roughly 3. Straw bales perform at about R–1.45. Snow is roughly R–1. • Absolutely still air has an R-value of about 5 but this has little practical use: Spaces of one centimeter or greater will allow air to circulate, convecting heat and greatly reducing the insulating value to roughly R–1 Thermal Considerations 01/17/2008 Lecture 4 5 Winter 2011 UCSD: Physics 121; 2011 17 Winter 2011 UCSD: Physics 121; 2011 18 Winter 2011 UCSD: Physics 121; 2011 19 Winter 2011 UCSD: Physics 121; 2011 20 Thermal Considerations 01/17/2008 Lecture 4 6 Winter 2011 UCSD: Physics 121; 2011 21 Winter 2011 UCSD: Physics 121; 2011 22 Winter 2011 UCSD: Physics 121; 2011 23 Winter 2011 UCSD: Physics 121; 2011 24 Thermal Considerations 01/17/2008 Lecture 4 7 Winter 2011 UCSD: Physics 121; 2011 25 Winter 2011 UCSD: Physics 121; 2011 26 Winter 2011 UCSD: Physics 121; 2011 27 Winter 2011 UCSD: Physics 121; 2011 28
