DOE Commercial Building Asset Rating: An Application of Centralized Modeling Tools

This paper presents a novel approach used to develop the U.S. Department of Energy (DOE) Commercial Building Asset Rating, which is intended to help building owners better understand the installed system performance and the total energy use. A simplified data collection and energy-modeling method is employed to disaggregate building energy information. Furthermore, the approach outlined will also include a mechanism for identifying energy improvement opportunities. A detailed modeling approach to formulate an Asset Rating would most likely provide the greatest flexibility and accuracy. Such an approach would, however, require a substantial amount of user investment for collecting the energy audit, data and hiring a professional to perform energy modeling and analysis. A simplified model approach requires fewer input combinations, which could reduce opportunities for error and allow an inexperienced user to quickly develop energy models. However, the accuracy of the results is often questionable. To address the above issue, the method presented in this paper separates model inputs into categories based on overall energy impact, difficulty to obtain, and variability among buildings. We outline an approach that will allow great flexibility in terms of how many and which of the different categories of variables must be found to produce anmore » accurate energy model. The approach will allow all key variables to be inferred from some minimum set of variables while at the same time allowing a user to enter many more variables if he or she has reliable values for them. The approach outlined will also provide constant values for some variables and algorithms for finding those which are very difficult to determine in the field. The whole of this approach will reduce modeling time and expertise required while maintaining accuracy and the ability to support the variability and complexity that exist in buildings. Therefore, the goals of facilitating cost-effective investment in energy efficiency and reducing energy use in the commercial building sector are met.« less