DA-13-003 -- Evaluation of Calculation Models for Predicting Thermal Performance of Various Window Systems PDF

This paper deals with prediction methods for evaluating the thermal performance of various window systems, such as single glazed with blinds and exhaust system, low-e double glazed with blinds, and airflow windows (AFW), and doubleskin facades. Calculation models to evaluate both loads and the thermal environment near the window were developed for each window system by solving the heat balance equation for each window element. The precision of these models was evaluated by comparing the calculated predictions with the results of tests or measurements. These models (window models) were shown to reproduce the test and measurement results reasonably well. Case studies were also conducted using annual simulations for various window systems by evaluating both thermal loads and the thermal environment near windows. It was confirmed that double-skin facades and AFW have better performance compared with other window systems when transparent glazing is used, that the low-e double glazed with blinds results in a relatively high annual cumulative cooling load due to the low heat release through the windows in the spring and autumn, and that it is possible to reduce the cooling loads and improve the thermal environment by using glazing with low solar transmittance.