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Aerogels, due to their superior thermal insulating properties, are slowly and steadily finding application in the building industry. In this paper, first a review on the synthesis of aerogels is presented. Aerogel preparation involves expensive precursors, chemicals, and the need for supercritical drying, making the production relatively more expensive compared to the current conventional building insulations. Several approaches that may lead to potential reductions in aerogel prices are also discussed. Next, the theory behind the thermal transport in aerogels is described.The reduction in the thermal conductivity of the aerogel is attributed mainly to the presence of nanoscale pores and the low solid volume fraction. Finally, the potential cost-effectiveness of aerogels as thermal insulation for internal wall retrofit applications is evaluated. Costs for several scenarios are estimated where aerogel blankets with different target R-values were installed from the interior of the building on top of the gypsum board. Further, these estimates are compared with retrofit costs associated with the application of conventional building insulations on the interior surface of the wall to achieve similar thermal performances. For a target value of 0.7 mK/W (R-4 ft2F/Btu), the cost analysis shows that significant savings of ~35% can be achieved by installing aerogel compared to interior conventional insulation methods. For a target value of 1.41 mK/W (R-8 hft2F/Btu), the aerogel method is determined to be costeffective compared to the current price range of conventional insulation methods, except for the fiberglass method. In addition, for a target value 2.11 mK/W (R-12 hft2F/Btu), it is found that the aerogel method is ~18%-23% less expensive compared to the cases where the conventional insulation is applied on the exterior surface of the wall.

Citation: ASHRAE Transactions - Volume 120, Part 1, New York, NY