Comparative study of Hot Box Test Method using laboratory evaluation of thermal properties of a given building envelope system type

Abstract

This research mainly focuses on the experimental setup of the Hot Box Test Method and comparison of different models for measurement of thermal properties of building envelope systems. Hot Box Test Method has long been used to determine the thermal properties of building envelope systems, however, the steady-state assumption for calculation is not always desired, especially when the environmental conditions cannot be controlled. To utilize models considering the dynamic behavior of buildings for in-situ measurement, it is desired to first validate such models and compare the performances with hot box test. Therefore, the performances of several dynamic models, including Anderlind's Regression Model and R-C Network Model, have been studied. Hot box tests were performed in the Building Enclosure Testing Laboratory (BETL) at Penn State University and the results show the 3R2C model turns out to be the most accurate one among the dynamic models explored in this study. With a temperature difference larger than 20 °C, all dynamic models are validated with a percentage difference lower than 7% compared with the steady-state analysis, giving us alternatives for R-value measurement when in-situ measurement condition are applied.