Development and Use of the Energy Model of a Research and Demonstration House with Advanced Design

Advances on manufacturing processes and the use of new materials are increasing the efficiency and reducing the cost of energy efficient and renewable energy technologies to a point that their deployment will reach desired levels for the sake of energy security and environmental concerns. Along these advances, the demonstration of the cost-effectiveness of this technology is vital to educate people and promote deployment of these technologies. In this sense, at the University of Texas at Tyler, two research and demonstration houses were built. House #1 is a conventional design with some advanced features, and House #2 has more advanced design features. In this study, House #2 is considered, which has relevant characteristics such as net-zero energy with 7.4 kW of solar photovoltaic system, advanced wall framing with open-cell foam insulation (R-24), unvented attic with open-cell foam insulated roof deck (R-24), vinyl-frame windows with double-pane, low-E glass (U=0.33, SHGF=0.23), ducted single-split system in attic (19.0 SEER, 9.0 HSPF), and high solar reflectance shingles. Since building energy performance depends on many factors, different scenarios or design characteristics can be assessed by using an energy model. In this study, the software OpenStudio (version 1.7.0) is used to develop a model for House #2. The software, developed by the National Renewable Energy Laboratory, is a user interface for the well known whole building energy simulation engine EnergyPlus. This paper shows the more relevant steps on model development. As a means of validation of the model, energy consumption from the model is compared against monthly energy consumption data in a calibration approach that is available in the software. As an example of the use of energy models, since the house has high solar reflectance shingles, the model is used to evaluate solar absorptance of shingles as a design parameter that can reduce energy consumption during cooling season but increasing energy consumption during heating season.