Building type: Commercial Offices
Project name: Pixel
Project objective: To design and construct the world’s first carbon neutral and water balanced office building with regard to both operational and embodied carbon emissions. Results: Modelled Perfect 105 point Green Star score (Australian GBC) 105 out of 110 point LEED score (USGBC), ten points more than the previous best rated building.
Status: Completed July 2010.
The Pixel Building, located in Carlton, Melbourne, Australia, is a six-story office building that has garnered international recognition for its groundbreaking approach to sustainability. Completed in 2010, it was designed by Studio505 and developed by Grocon. The building achieved a perfect score of 105 points under the Green Star rating system, making it one of the most sustainable buildings in Australia and a global leader in environmentally conscious design.
Building Description Pixel is a four level structure using reinforced concrete
floor slabs, lift core and easterly shared wall. Double
glazed low-e external envelope is used for the north,
west and south facades. The building also has a green
roof. Significant design effort was invested to ensure that a
large proportion of the building envelope is able to be
removed and re-used in order to reduce the future
footprint of the building when it is demolished.
The concrete used at pixel is a new design that has
been developed and patent-protected by Grocon. The
concrete is called “Pixelcrete” and under third party
independent review undertaken by RMIT University’s
Centre for Design, the design was shown to almost
halve the embodied carbon of the mix when compared
with traditional 40MPa concrete mix designs. This
product has now been made available to the
construction industry in Australia via an industry
partner.
100% fresh air (ie no re-circulation) is circulated
throughout the building via the floor spaces and is
controlled via floor vents at each work station. This
facilitates passive night cooling of structural exposed
floor slabs.
Cooling strategy
Heating strategy
A heat exchanger captures energy from
the exhaust air to pre-heat or pre-cool the incoming
fresh air. The thermally active floor slabs directly
condition the office spaces through radiant cooling,
and indirectly condition the spaces be pre-conditioning the incoming fresh air.
Key Sustainable Design Features
The Pixel Building incorporates a wide range of innovative technologies and design strategies to minimize its environmental impact.
These features can be broadly categorized as follows:
1. Water Management
Vacuum Toilets: These toilets use significantly less water per flush compared to conventional toilets, reducing overall water consumption.
Rainwater Harvesting: The building collects rainwater from its roof and other surfaces, storing it in a large underground tank for use in toilet flushing, irrigation, and cooling systems.
Greywater Recycling: Wastewater from showers and sinks is treated and reused for non-potable purposes, further reducing the demand for potable water.
Green Roof: The building features a green roof that helps to absorb rainwater, reducing storm water runoff and providing insulation.
Reuse is achieved on a number of levels. Water falling
on the Pixel building as rainwater is collected after it
has been used to irrigate the native Victorian
grassland species re-introduced in the roof garden.
The rainwater is stored in tanks before being treated
by reverse osmosis to potable water standard. This
treated water is distributed to all fixtures and fittings
within the building and the resulting grey waste water
is then filtered and directed to the living edge reed
beds where it is used to irrigate the reeds and plants.
This process means that there is no grey water waste
leaving the Pixel site except for the wettest month of
the year in Melbourne, dramatically reducing the waste
flow to sewer.
Edge reed beds receive grey water from showers
and sinks
The anaerobic digester on the ground level holds all of
the black waste from toilets and kitchen facilities. The
methane is extracted and used as the energy source
for the hot water heaters on the roof. These in turn
provide the hot water to the showers that
subsequently produce the grey water that irrigates the
reed beds. The black waste is then sent to the sewer
in a liquefied form and with reduced methane levels.
2. Energy Efficiency
Solar Panels: The building is equipped with a large array of solar panels on its roof and facade, generating renewable electricity to offset its energy consumption.
Both the reduction in demand and carbon intensity allowed for relatively small renewable energy sources to be installed onsite to achieve a net balance of carbon emissions. Renewable energy systems were designed into the building and consist of fixed and tracking photovoltaics and wind turbines on the roof, in addition to a small amount of biogas produced from an anaerobic digester connected to the vacuum toilet black water system. The wind turbines and photovoltaics are grid connected and use the grid as a ‘bank’ where excess renewable energy is exported. The nature and time of energy generation was also considered. Peak loads in Australia are related to cooling energy demand with the biggest need occurring during summer mid-days. The use of site based wind and solar power generation matches well with this system need and creates a direct relationship between peak power generation and peak grid load.
Natural Ventilation: The building is designed to maximize natural ventilation, reducing the need for air conditioning and lowering energy consumption. Operable windows and a central atrium facilitate airflow throughout the building.
High-Performance Glazing: The building's windows are made of high-performance glazing that reduces heat gain in the summer and heat loss in the winter, minimizing the need for heating and cooling.
Automated Shading: External shading devices, including the building's distinctive "pixels," automatically adjust to the sun's position, blocking direct sunlight and reducing glare and heat gain.
The façade, or using materiality to create a permaculture of timber and vines. Precursors to Pixel looked green, a trend this building aimed to buck through its colorful façade.
Looking to reduce the material waste from the project, a geometric system for the façade panel shapes was devised from the Cairo tile pattern – a tessellation of irregular pentagons that overlap to fill a shape. A nod to the previously completed studio505 project, Suzhou Science and Cultural Arts Centre, this technique allowed standard rectangular panels to be divided and cut to form the cladding with nearly zero wastage.
Using leftover colored panels from a major cladding supplier, the tiling pattern was mapped onto the panels then digitally distributed on the northern, western and southern elevations to achieve optimal daylight, shade, solar thermal exposure, and appearance.
Energy/Carbon Emissions
A strategy of energy demand reduction, low carbon
intensity fuel sourcing, and on-site renewable energy
generation was followed in order to reduce carbon
emissions.
Firstly, the building was designed in order to reduce
energy demand. This focused on energy efficiency in
the façade and services to minimize the energy
required for lighting, heating, cooling and ventilation.
As an example of this thinking, the whole building
uses only two fans, one for supply air and the other for
exhaust. Other measures include external shading
system to minimize solar thermal loads, individual
addressable dimming on the office lighting, and LED
lighting to all non-office areas of the building.
A reliable fuel source was required for the building’s greatest energy demand, heating and cooling. Gas, with a carbon intensity of 0.21 kgCO2e/kWh, was selected over the traditional Victorian brown coal powered grid electricity, which has a carbon intensity over six times greater (1.34 kgCO2e/kWh). A gas fired absorption chiller using ammonia refrigerant was used.
In addition to dramatically reduced carbon emissions,
the refrigerant has no ozone depleting potential, nor is
there any possibility of legionella. The natural gas
supply also acts as a back-up for the anaerobic
digester.
Absorption Chiller: An absorption chiller uses waste heat from the building's cogeneration system to provide cooling, further improving energy efficiency.
Cogeneration: The building utilizes a cogeneration system that produces both electricity and heat from a single fuel source (natural gas). This system is more efficient than traditional power plants, reducing greenhouse gas emissions.
Environmental Performance and Certifications
The Pixel Building has achieved several significant environmental certifications, including:
Green Star – Office Design v3: The building achieved a perfect score of 105 points under this rating system, demonstrating its exceptional environmental performance.
LEED (Leadership in Energy and Environmental Design): The building is also LEED certified, further validating its sustainability credentials.
Impact and Legacy
The Pixel Building has had a significant impact on the field of sustainable architecture. It has demonstrated that it is possible to design and construct buildings that are both environmentally responsible and aesthetically pleasing. The building has inspired architects, developers, and policymakers around the world to adopt more sustainable building practices.
The Pixel Building serves as a living laboratory for sustainable technologies and design strategies. It continues to be monitored and studied to assess its performance and identify areas for improvement. The lessons learned from the Pixel Building are being applied to other sustainable building projects, helping to advance the field of green building.
Challenges and Lessons Learned
While the Pixel Building has been a resounding success, the project also faced some challenges:
Cost: Sustainable building technologies and materials can be more expensive than conventional options. However, the long-term benefits of reduced energy and water consumption can offset these initial costs.
Complexity: Designing and constructing a highly sustainable building requires a high level of expertise and coordination.
Public Perception: Some people initially questioned the building's unconventional design. However, the building has since become a popular landmark and a symbol of Melbourne's commitment to sustainability.
The Pixel Building demonstrates that sustainable building is not just about reducing environmental impact; it is also about creating healthier, more comfortable, and more inspiring places to live and work. It serves as a powerful example of how innovative design and technology can be used to create a more sustainable future.
Why It Works:
The pixelated façade doesn’t just look iconic—it’s a bioclimatic system.
Sun control + insulation + ventilation combine to:
Lower indoor temperatures
Reduce cooling loads
Enhance indoor air quality
The building achieved a LEED Platinum and 6-Star Green Star rating, making it one of Australia’s greenest buildings.
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