Suppose a home's UATOTAL for heating is 1500 BTU/hr-F. Suppose the average outdoor temperature over a day is 28F and the desired indoor temperature is 68 F. Any electricity the heating system uses comes from a power plant burning natural gas with 60% conversion efficiency, and with energy losses of 6% in electricity transmission and distribution and 0% losses in natural gas distribution. Draw the energy chain and calculate the primary energy (in therms of natural gas) that is used over the day when the home uses an air-source heat pump with HSPF = 13. d. 'Aerogel' is a material with a thermal conductivity k of 0.01 BTU-in/hr-ft2-F. Is this material a thermal insulator or a conductor? Calculate the R and U values for a block of this material that is 3 inches thick. Now sandwich this block of material between two sheets of R-0.8 fiberboard. What are the new effective R and U value