It has long been acknowledged that access to fresh air is critical for peak performance and health, whether a person is working in office or learning in a classroom. Whilst operable windows and cross flow ventilation can offer good levels of fresh air and natural cooling there will be times when ambient conditions are unfavourable. At such times occupants will want to and should be able to close windows.
In much of Victoria the incidence of hot summer afternoons and cold winter mornings are frequent enough to warrant a back up supply of tempered fresh air.
The latest generation of Victorian government schools are addressing the need for back up of tempered fresh air by introducing low energy systems that take advantage of conditions such as diurnal swings and thermal mass storage. An article in the Ecolibrium October 2010 edition detailed the system adopted at the Meadows Primary School in Victoria (by NOW Architecture)where water was used as a thermal storage system through which ventilation pipes drew air to be cooled.
The Mt Clear Earth and Science Centre designed with SBE responded to the same demand for tempered fresh air by incorporating a ground coupled thermal labyrinth and was the focus of another article in Ecolibrium in 2011.
The graph shown above demonstrates how ambient air at 5pm is cooled from 30°C to 22°C after being drawn through the labyrinth.