A Field Study and OpenStudio Calibration of Two Mass Timber Buildings in the United States

Cross laminated timber (CLT) are massive timber plates composed of layered boards arranged crosswise and glued together. They enable faster construction times than traditional building methods by taking advantage of prefabrication. CLT construction in the US is expanding but until now no study has analyzed its energy performance in the field. This study is part of a larger study that has the goal to field test four CLT buildings for more than a year and use the collected data to validate OpenStudio (OS) in mass timber buildings. OS was selected for this study because it uses EnergyPlus as its simulation engine which has the ability to simulate moisture interactions between building materials and interior air and is commonly used for building analysis and design. The analyzed buildings focused on in this paper are an office building and a training center located in the Denver, Colorado USA north metro region. This study shows preliminary field data and OS calibration results for the building models. Additionally, these buildings have been specially fitted with plug load and non-invasive electric load monitoring. OS model electric results have been calibrated following ASHRAE Guideline 14 for whole building calibrated simulation based on 2021 utility data and actual meteorological year data. This study demonstrates being able to calibrate the CLT building models to meet ASHRAE Guideline 14 criteria, however much uncertainty remains in how accurate the calibration matches sub hourly building operation. Future work will calibrate the CLT models against the sub-hourly load and operating data currently being collected to isolate the influence of moisture buffering in the structure on model predictions.