Chris Howe is a chartered architect and sustainability consultant. A member of the NSW Institute of Architect’s Environment Committee, Chris has represented the Institute on state planning reforms, and is a recently elected local councillor passionate about sustainability of both the built and natural environment.
The architect's own home, this award winning project is a continuation of the pursuit of the integration of modern high tech architecture with sustainable design principles, practice and materials with a particular emphasis on self sufficiency in energy and water use.........and proof that it can be done.
Fundamental to the brief and architectural philosophy, was the desire to create a contemporary home which promotes exemplary sustainable design principles through the integration of traditional passive environmental controls, with modern technologies and materials.
Carbon neutral on operational energy, a 16.8 Kwh photo voltaic system is integrated within the atrium roof, utilising the latest BP solar panels and connected to the local electrical grid, the photo voltaic system producing in excess of the buildings total energy consumption.
Commitment to energy efficiency throughout the life of the building includes a wide range of passive and active environmental design features, including material durability, extensive insulation of the building envelope, draft efficient joinery, double glazing, automated solar louvres, extensive use of LED and fluorescent lighting, thermal mass and natural cross ventilation.
The atrium is the central focus of the house, both aesthetically and functionally, the high void enables passive evaporative cooling in summer, with cool air entering at low level over an exterior pond, and hot air exiting at the upper level through a combination of venturi and convection effects, controlled by automated high and low level windows.
Solar radiation heat gain in summer is controlled by building orientation, large roof and balcony overhangs, automated exterior louvres, and extensive double glazing, while solar radiation and heat retention in winter is achieved through solar reflection, thermal mass, double glazing and the building envelope's high insulation rating.
A significant design feature is the large sandstone blade wall which cuts through the house externally and internally, however like many features of the house, this wall serves an important environmental function, passively maintaining ambient internal temperatures through its thermal mass. In summer cool night air is slowly released during the day, and in winter captured solar heat is slowly released at night minimising the need for active heating/cooling.
In keeping with an holistic view to sustainability, the sandstone used in the blade wall was sourced from the excavation of a commercial carpark, and transported and processed into panels at a local Sydney quarry, saving precious natural resources and negating additional landfill.
This holistic approach extends to the 28,000 litres of water storage and recycling, where a three tiered design has enabled the building to be potentially self sustainable in water use ( subject to changes to NSW health regulations ). Encapsulated within the concrete floor, proprietary in slab tanks store 12,000 litres of rainwater collected from the non trafficable areas of the roof, which after sanitising is used for toilets, swimming pool, and ponds. I
ntegration of the rainwater tanks within the thermal mass of the concrete slab, which in turn is insulated from the ground, enables surplus winter heat from the roof mounted solar panels to be continuously recycled through the rainwater tanks increasing the temperature of the slab and therefore decreasing winter heating requirements.
To maximise water recycling, overflow from the rainwater tanks, approximately 85% of stormwater from the site, and subterranean ground water flows are reticulated to two 5,500 litre subterranean storage tanks and used for garden irrigation, while greywater from baths, showers and basins is also recycled for garden irrigation.
Roof top mounted solar panels, boosted in winter by natural gas, provide all hot water requirements, and to maximise efficiency, a low energy pump reticulates cold water within the plumbing system back to the hot water cylinder to prevent waste.
During concept design for this project, careful consideration was given in the selection of building materials regarding, ( i ) environmental sustainability of source ( ii ) embodied energy ( iii ) durability, ( iv ) construction methodology and waste, and ( v ) recycling potential, in order to balance these factors against the operational energy requirements of the building's expected 50 year life.
Considering that international studies have confirmed that 80% of the total energy used in the construction, use and demolition of buildings is accounted in operational energy, this balance of operational energy against sustainability of building materials is an important one. Consequently while materials were chosen due to their sustainability of source, embodied energy, durability, waste reduction and future recycling ability, these attributes were considered against their combined ability to control energy efficiency through thermal mass, insulation and passive environmental controls.
Rendered reinforced concrete block is used predominately for external walls, the proprietory blocks containing 30% flyash from the Port Kembla steel mills. The flyash in the block encapsulate a waste product environmental damaging and difficult to dispose of, while making the block 25% lighter, reducing CO2 in transport and installation.
Ground floors are constructed in reinforced concrete for thermal mass, the concrete insulated off the ground using recycled polystyrene from appliance packaging, however the first floor and roof structures dispense with traditional concrete construction for a lightweight timber structure.
The choice of plantation grown pinus radiata Laminated Veneer Lumber ( LVL ), Plywood and Particle Board over concrete for the first floor and roof structures enabled a reduction of approximately 18.5 tonnes of CO2 into the atmosphere ( embodied energy ). Plantation grown timber also being used for soffits, claddings, decks and fencing.
Natural wool is used extensively as an insulation barrier in walls and ceilings , and the entire roof area is covered in light coloured locally sourced river pebbles to reflect and dissipate solar heat in summer and increase insulation in winter.
While structural integrity of the large open plan areas required for natural ventilation necessitated extensive use of structural steel to support the reinforced concrete block walls, bolted connections over traditional welding reduced energy during construction, while allowing future recycling of all steel.
Similarly increased embodied energy through extensive use of glass was offset by the building's ability to achieve passive ventilation by solar radiation and convection, while large joinery dimensions ensure future glass recycling.
Careful consideration has been given to all aspects of environmental sustainability in this project, from energy efficiency, water recycling, material selection, and architectural detailing...............however the real success of this house is arguably in the team approach by the architect, consultants, and contractors which has resulted in high tech contemporary architect with a social conscience.
FACTS:
Carbon neutral on operational energy utilising 16.8 Kwh Grid Connected Photo Voltaic System with latest technology BP Panels.
- Solar Hotwater System, with cold water return cycle, and natural gas boosting.
- Energy efficient LED ( light emitting diodes ) and fluorescent lighting, all appliances rated 6 star.
- 28, 000 litres recycled water storage integrated within the building structure, including 12,000 litres of rainwater in proprietary tanks encapsulated in the concrete floor.
- 85 % of site water recycled, toilets, laundry and pool use recycled water, all grey water recycling for garden irrigation.
- Passive heating and cooling through; innovative “stack” ventilation, evaporative cooling, thermal mass, external automated louvers, building orientation, and extensive use of double glazing.
- High thermal insulation of building elements, including insulating concrete slabs using recycled polystyrene from appliance packaging, natural wool in floors and ceilings, and solar reflecting river pebbles over roof.
- 70% energy savings on active heating and cooling through high efficiency heat pumps, individual zoned fan coil units, and “on demand” temperature controls.
- Use of environmentally sustainable building materials including exterior walls utilise concrete blocks with 30% waste flyash content, and use of plantation grown timber over traditional concrete construction resulted in savings of 18.5 tonnes of CO2 emissions.
FURTHER INFORMATION & CONTACT:
For fact sheet, further information and details of principle suppliers for this project please feel free to contact the architect directly.
Chris Howe
Howe Architects
02 93281198
Email: chris@bossleyhowe.com
(August 2009) (
