Predicting Occupied Zone Temperature Using Simplified Modeling Methods

Due to the expected level of thermal stratification that is present in buildings which are subject to high levels of infiltration during the heating season, the well mixed modeling approach may not be an appropriate method for modeling interior conditions in structures with inefficiently constructed envelopes. A simplified modeling method known as the Three-Node Displacement Ventilation RoomAir Model was developed by da Graça (2003) for predicting levels of thermal stratification present in buildings utilizing displacement ventilation systems (DV). This paper examines the level of thermal stratification in a building with no forced air that is subject to high levels of infiltration during the heating season, and the ability of the Three-Node Displacement Ventilation RoomAir Model to accurately model the thermal stratification therein. It was found that the levels of thermal stratification in the test building were such that the well mixed modeling approach is not appropriate. However, the Three-Node Displacement Ventilation RoomAir Model was also found to be unsuitable for modeling the conditions set forth in this research due to the methods for predicting temperature distribution utilized in the model. It was concluded that another method for modeling thermal stratification in loosely constructed buildings during the heating season should be developed.