Experimentation of Hybrid Ventilation in Carnegie Mellon University's Intelligent Workplace, Pittsburgh, PA

The Center for Building Performances and Diagnostics of Carnegie Mellon University is experimenting with Hybrid Ventilation in Pittsburgh, Pennsylvania, USA, to evaluate the potential energy savings of this technique in a region where there are many variations in climate throughout any given year. Sharing the results of this experiment aims to increase awareness of this technique in the US and develop its implementation in the future. The current project consists of opening different 8 windows, located in 2 offices and a conference room of the Intelligent Workplace, when specific conditions are met and using the mechanical system otherwise. The mechanical system includes a desiccant wheel unit that conditions outside air to a set humidity and temperature, and mullions where chilled water is circulated to cool the space. The experiment, started in spring 2009, will establish the number of hours of natural ventilation at night and during occupation time and evaluate the energy saved. The success of such a system lies in the algorithms followed to fully operate hybrid ventilation based on measurements of outdoor and indoor conditions: temperatures, humidity, wind velocity, rain, occupancy, etc. The one developed at CMU has been programmed in TRNSYS to evaluate the energy saving and the hours of window opening: About 10% of energy is estimated to be saved which will be compared to the experimental results of spring, summer and fall 2009.