An Innovative Approach to Reducing Duct Heat Gains for a Production Builder in a Hot and Humid Climate-How We Got There

摘要

The Consortium for Advanced Residential Buildings (CARB), one of five Building America industry teams, has been working with Mercedes Homes in Melbourne, Florida, to improve their product with energy-, material-, and labor-saving strategies. Typical construction for Mercedes, and other builders in the area, is a single-story on a slab foundation with all HVAC supply ductwork in the attic feeding ceiling supply registers. A key element of the systems engineering approach for most Building America projects has been to improve space conditioning system efficiency by reducing or eliminating duct losses or gains. To date CARB has worked with Mercedes through the design and construction of three different homes involving different innovations. A different strategy for addressing the attic duct heat gain has been applied in each of the three homes. The first strategy was to bury the ducts under blown attic insulation, and monitoring was performed to assess the potential for condensation problems on the surfaces of the ducts. The second strategy brought the ducts down out of the attic and hid them in dropped ceiling chases. The third strategy involves an innovative redesign of the roof trusses to provide a chase space for the duct system that can be isolated from the attic conditions. This paper farther describes each of the three strategies and their field implementation.