The combined effects of thermal mass and insulation on energy performance in concrete office buildings

Considering the use of concrete in structural and cladding applications, and energy code requirements for inclusion of thermal insulation in building envelopes, an investigative study was carried out to determine how the interaction between thermal mass properties of concrete and thermal insulation in the building envelope affects the building energy performance. This study examines how the combination of thermal mass and insulation influences building energy use in eight U.S. climate zones through Energy Plus simulation. The measuring parameters include the concrete wall thickness and relative location of thermal insulation with respect to the thermal mass wall. Building energy consumption is measured in terms of annual heating and cooling energy demands, as well as total energy use. The paper presents conclusions about the potential benefits of thermal mass and insulation for office occupancy. The results have shown that in cold climates the addition of thermal insulation to a concrete enclosure provides significant further benefits beyond those provided by thermal mass alone, whereas in hot locations those benefits are fewer. These results also indicate that other influential design variables such as occupancy type could also demonstrate broader implications of the integration of thermal mass and insulation in different climate zones.