UC Berkeley

This paper describes the performance, in terms of indoor environmental conditions, of three buildings from both the U.S. and India that use night ventilation as their primary cooling method. The first building, located in Oakland, California, uses forced ventilation at night to increase the airflow.  The second building, located in Sunnyvale, California, uses automated natural ventilation at night.  The third building, in Auroville, India, uses natural ventilation by means of occupant-controlled windows.  The analysis is based on three months, two months, and a full year of monitored data collected from each building, respectively, of indoor and outdoor conditions. The indoor conditions of each building were first tested for compliance with comfort standards in the US and India.  A hybrid model was then developed, using both first principle equations and the collected data, to predict the instantaneous air and mass temperatures within each building.  The cooling strategy effectiveness was then assessed by comparing indoor conditions from days that did and did not use night ventilation, comparing performance across the different climates and types of night flushing.  Finally, the ventilation controls for each building were optimized using the hybrid model.