EVALUATION OF SELECTED DYNAMIC MODELS IN COMPARISON WITH HOT BOX TEST RESULTS FOR MEASUREMENT OF BUILDING ENVELOPE THERMAL PROPERTIES

Abstract

ABSTRACT This research is mainly focused on the experimental measurement of R-value by several different models. Building energy consumption accounts for about 40% of the total energy use in the U.S, and therefore accurate energy simulation is desired. The R-value is one of the key parameters that can influence the energy simulation results and therefore is of great importance. The Average Model has long been the most widely accepted method to measure the thermal properties of building components. However, its steady-state assumption and dependence on temperature difference limit its use especially for in-situ measurement. In this study, several dynamic models, including the Pentaur Model and R-C Network Models, are studied with test data obtained from a series of hot box tests performed in the Building Enclosure Testing Laboratory. The results show that the 3R2C model has the best performance and a desirable stability of accuracy with respect to different levels of temperature difference, and therefore is recommended for practical measurement. The results also indicate that unlike the Average Model, the accuracy of dynamic models does not necessarily depend on the level of temperature difference.