Sky modeling systems developed around the world aim to accurately predict the amount of sunlight at particular times by building mathematical models from recorded data about the local conditions of the sky.

A good understanding of sunlight provides us with a tool to effectively use natural light in the built environment.

Professor Roy explained that good sky models will help conserve energy used by artificial lighting through the production of more efficient window and interior lighting designs.

“With accurate data, we may be able to develop windows and interior lights that adjust their brightness according to the amount of outside light,” he said.

“Having these sensors in buildings will lead to significant long term energy savings for building owners and operators.”

According to Professor Roy, the analytical tools for sunlight modeling have been built mainly for European and North American climates and are not always well adapted to other climatic zones, especially Australia.

The models are built from recording data about local conditions of the sky, so each model fits best into the particular atmospheric conditions found in its place of origin.

“Sunlight levels are not simply drawn from weather patterns, as other factors such as pollution can have an effect,” said Professor Roy.

By entering a particular latitude, longitude and parameters such as the local time and date, Professor Roy’s online modeling package will enable researchers to develop their own models. They will also be able to compare the results of each modeling system to find one that best suits the region’s conditions.

There are currently six models available at the sun website that were developed for a range of atmospheric conditions.

They were mostly developed by researchers working with the Commission de l’Eclairage (CIE), an international organisation concerned with light.

The CIE coordinates the international standards of lighting levels and Professor Roy’s work in collating these models will soon be used to assist in revising these standards.