Autonomous Zero Carbon Life Cycle Building

Located in the heart of Sydney CBD, Legion House was originally constructed in 1902 by the YWCA and operated as a women’s hostel and was an outreach service for 60 years. The building is Heritage listed and protected due to its social significance. As part of its innovative redevelopment, Legion House acquired an additional two levels (now five levels in total) along with state-of-the-art-technology making this building one of the most sustainable designs in the world. It was also certified with a 6-star Green Star Office Design (v2) rating from the Green Council Building Association.

Sustainability Measures:

The development of Legion House balanced the parallel challenges of heritage preservation whilst enhancing the building’s overall utility and environmental performance. “By adopting a contemporary design approach to new elements and juxtaposing new design with heritage elements, Legion House achieves an authentic response to the building’s heritage values,” explains Sean McPeake (Project Architect) from francis-jones morehen thorp.

Legion House has been refurbished as a fully zero and is Australia’s second zero carbon building. Legion House creates its own renewable electricity on site resulting in zero net carbon emissions and is disconnected from the electricity grid, with any surplus power created by its independent system to be supplied to the 50 storey commercial office tower on the site.

Legion House receives little sun or wind making these unsuitable as renewable energy sources. Instead, the project receives its energy from a process called biomass gasification. “The technology converts plant sourced materials into a combustible gas that is used to generate electricity,” explains McPeake. “This is effectively a carbon zero energy source as the greenhouse gases released in the energy production equal that absorbed in creating the biomass.” Whilst, gasification systems are not new, they tend to be either very large industrial systems, or as a back-yard hobby. However, what is new, is the size and application in a city environment on a 6 storey building (Legion House). There are no atmospheric emissions from the gasifier which simply produces biogas and char(ash).

Furthermore, traditional gasification plants utilise standard wood chips or briquettes made from compressed waste sawdust. Legion House can utilise the commercial paper waste generated from the adjacent office tower through shredding and compressing this waste to form paper briquettes, which can then be used in the gasification plant to produce a usable Syngas. The ‘first’ of this type of technology used in a large scale commercial office.

While Legion House can be referred to as a Carbon Neutral building, it is technically classified as an ‘Autonomous Zero Carbon Life Cycle Building’, – under the Australian Sustainable Built Environment Council definitions. This essentially means a building that is disconnected from the electricity grid that uses renewable energy to offset carbon emissions from its operations and embodied energy over the life cycle of the building.

Air conditioning is provided throughout Legion House using chilled beam technology. The ventilation provided with the chilled beam system uses 100% fresh outside air to maintain a very high level of indoor environment quality for the occupants.

In addition to energy, Legion House has been designed to be water balanced. This means that in a year of typical Sydney rainfall, all the amenity and operational water needs of the building will be met through rain captured on the roof. This is achieved through the use of advanced water conservation technology, high efficiency fixtures, vacuum toilets and the use of high quality rainwater recycling.

The development is the product of an architectural vision driven towards positive outcomes for the community through the public domain interface including a strong emphasis on creating sustainable public spaces, an interesting urban form, public art and community awareness.

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