Commercial buildings in Australia currently account for approximately 10 per cent of our greenhouse gas (GHG) emissions while cooling demands 28 per cent of the sectors total energy use (Australian Greenhouse Office, 1999). In 2008, Saelens acknowledged this issue and stated that ¡§The awareness for environmentally friendly and energy conscious building design urges the need to develop new facade technologies¡¨. The energy efficiency benefits of double skin facades (DSFs) on large commercial buildings however has typically only been associated with cold European climates, largely ignoring their potential benefits in tropical and sub-tropical areas. Furthermore, studies have used a variety of methods including spectral optical modelling and computational fluid dynamics but ignored the need for the development of practical engineering design software suitable for DSFs.
This thesis study presents a method of DSF analysis using the building energy simulation software IES-VE. Using this method, the energy performance of a naturally ventilated DSF in the sub-tropical climate of Brisbane, Australia, is compared to a base case single skin facade. The impact of solar gains, external conduction, light dimming, cavity louvre size, adjacent buildings and cavity blind profiles were assessed over a 12 month period.
The study found that:
• IES-VE is a practical but limited design and analysis tool for engineers in the assessment of DSF performance.
• DSFs can perform marginally better than SSFs in a sub-tropical climate.
• The DSF is highly effective at reducing the building's solar gains.
• Reductions in peak and annual boiler and chiller loads, boiler and chiller energy, total system energy and total building energy are possible.
• Venetian blinds within the DSF cavity greatly increase the DSFs performance.
• The "greenhouse effect" has a negative impact on the facades energy performance during cooling periods but is beneficial during heating periods.
• An increase in cavity louvre size results in increased cavity flow, reduced impact of the greenhouse effect and positive but minimal reductions in system energy.
• The utilisation of dimming profiles on artificial lighting can significantly reduce system loads and building energy.