Setting a new standard in medium density public housing Enter
Department of Human Services - Office of Housing Main menu 03 Introduction 05 Site Planning 07 Building Form 08 Passive Solar Design 10 Life Cycle & Materials 11 Water Systems 12 Energy 13 Landscaping 14 Facts & Figures 16 Project Details
Department of Human Services - Office of Housing Introduction K2 is an ecologically sustainable, medium density public housing development located at Raleigh Street, Windsor. The 96 unit project was initiated by the Victorian Office of Housing and designed by DesignInc Melbourne, in response to an open competition. The design embodies the philosophy of integrating sustainable architecture into the conceptual basis of the design not just as an added extra. The primary ecological objectives of the project were to minimise greenhouse gas emissions and water consumption, and to design for longevity through the use of reusable and recycled materials. Continued next page Concept sketch celebrating a solar aesthetic < >
Department of Human Services - Office of Housing Introduction True sustainability takes into account far more than energy and water savings. The approach taken with the K2 was to combine the notion of a healthy building and environment. The project considered the social and economic aspects of sustainability to be as important as the natural environmental aspects. Access to landscape, indoor air quality, natural ventilation and the provision of a variety of communal spaces were considerations in achieving a socially responsible development. The northern facade of integrated balconies and shading
Department of Human Services - Office of Housing Site Planning Urban Context Sited in an area of varied use, the K2 aim to provide a built form that is compatible with a sustainable future vision of inner urban Melbourne. Pedestrian access was given priority over vehicles, and sustainable landscaping was integrated into public and private courtyards. Display panels were integrated into a street accessed urban courtyard. Solar access was carefully controlled, both in terms of site spaces and surrounding buildings. Continued next page Site plan strategy
Department of Human Services - Office of Housing Site Planning Site Plan First principle passive solar design led to the expression of four connected buildings on the 4800m 2 site. The buildings are oriented on an east west axis to allow for maximum northern exposure, and were staggered on the site to allow for the creation of a series of public and private courtyard spaces. The height of the four buildings and the distance between the front and back pairs was carefully calculated to ensure that all units received northern sun all year round. Site plan strategy Green Spine The four buildings are linked by a shared Green Spine. Likened to a central nervous system, the spine integrates the functional and social aspects of the proposal. It was designed to emphasise community awareness and promote the sustainable functions of the building.
Department of Human Services - Office of Housing Building Form Each facade responds to its orientation and function. North facades combine balconies with solid bedroom walls while south walls integrate privacy screens with circulation. Facade and roof pod forms were angled for optimal solar panel placement as well as being self shading to levels below. Dwellings were designed with single loaded access walkways that allow cross ventilation through all the units. High levels of exposed internal thermal mass, combined with high levels of insulation, double glazing and appropriately designed shading enable a tight building fabric to minimise heat loss and gain through the envelope. The extensive exposed thermal mass provides internal thermal stability by naturally moderating the air temperature. Building Massing 4 staggered buildings of different heights orientated east - west to allow for maximum winter sun to all units Thermal Efficiency solid east/west walls use insulated structural precast coloured concrete for maximum thermal performance Varied facade north facades combine offset balconies with solid bedroom walls for self shading and visual variety 3 Solar Shading facade and pod roof forms angled for optimal solar panel placement and self shading to lower levels 4 2 1
Department of Human Services - Office of Housing Passive Solar Design By optimising the building form, orientation and circulation, thermal modelling showed that comfortable conditions could be expected for most of the year. Additional heating has also been provided by means of a central gas fired hydronic natural convector system that provides a better indoor air quality, lower energy consumption and reduces chance of burns and risk of gas leaks in the units. While the units are Grouped Venting rooftop ventilators and grouped exhust ducts and services Light & Air high level light and ventilation to pod units Thermal Mass exposed concrete ceilings and masonry walls provide thermal stability and reduce heating and cooling demands Cross Ventilation single loaded corridors allow cross ventilation Weather Protection south walkway screens provide weather protection and reduce wind pressures and effectively prevent uncontolled heat losses Renewable Energy photovoltaic and flat plate solar collectors to north roofs Self Shading summer sun excluded by pod architecture and projecting balconies naturally ventilated, a centrally located internal fan and roof level ventilators help purge excess heat build up in extreme conditions. Continued next page Solar Shading facade and roof forms angled for optimal solar panel placement and self shading to lower levels Social Spaces recycled timber, green spine provides winter sun penetration and summer and social meeting space shade Thermal Mass high levels of thermal mass, insulation, double glazing and window sunshading minimise heat loss and gain te un rs win gle an North Winter Sun northern winter sun and balconies to all living spaces Water Storage roof water storage tanks Water Recycling treated grey water reticulation supply system recycles water for landscape irrigation and toilet flushing Raleigh Street < >
Department of Human Services - Office of Housing Passive Solar Design Summer Mode Dwellings are designed with single loaded corridors that allow cross ventilation for physiological cooling. Facade design and orientation excludes high angle solar penetration. Exposed concrete ceilings and masonry walls provide thermal stability and radiant cooling. In an alternative extreme temperature summer mode, minimal daytime ventilation can allow for the retention and radiation of stored coolth by night time purging and pre-cooling of the heavy structure. Winter Mode Exposed concrete ceilings and masonry walls help to provide thermal stability and reduce peak heating demand. Convective heat transfer of passive gains can occur through the dwelling. Double glazed windows retain heat and limited window areas on the south, east and west reduce heat loss potential. Well insulated and sealed construction also keeps heat losses to a minimum. Individual windows ensure fresh air can be introduced in a relatively draught free manner. Screens to the south walkway provide weather protection and reduce wind pressures and effectively uncontrolled heat losses. Efficient gas hydronic convector radiators were provided to allow elevated comfort temperatures for elderly and disabled tenants. Bathroom and kitchen exhaust was provided via common structural blade riser ducts between units. Roof level ventilators provide extraction at high levels. Buffer zones Solar access taller buildings to the south Offset site planning allows solar access and site ventilation
10 Department of Human Services - Office of Housing Life Cycle & Materials A total life cycle approach to material selection was taken including the consideration of embodied energy, biodiversity, waste, end of life reuse/recyclability, robustness and toxicity to human occupants, manufacturers and to the environment. Key material responses include integrated natural finishes to minimise maintenance requirements (specifically painting) such as oxide finishes to concrete, colorbond cladding, expressed galvanised posts and screens. Flyash is used as a substitute to cement content in concrete to reduce embodied energy. Class 1 durability timbers were left to naturally age. Recycled and sustainably managed plantation timber was specified for external screens, window frames and for internal stud wall framing. A requirement of the project was to provide timbers that were sourced from sustainably managed forests with a Chain of Custody. Internally, low Volatile Organic Compound paints and carpet were specified to maintain a high indoor air quality. PVC was avoided where possible, with sanitary pipework and floor finishes being PVC free. Chain of Custody Chain of Custody (CoC) basically tracks a wood or forest product from its origin in a certified forest through to its end use as a wood or forest product by the consumer. CoC covers all intermediate steps such as harvesting, transportation, primary and secondary processing, manufacturing, re-manufacturing, distribution and sales. As such, CoC is an inventory control system that provides a quality assurance standard. Australian Standard 4707 (Int) 2004 (Expired March 2006, pending outcome of the recognition process by Standards Australia for AS 4707).
11 Department of Human Services - Office of Housing Water Systems A treated grey water reticulation supply system recycles water for irrigation and toilet flushing. Roof water is collected from all roof surfaces and stored in central water tanks. This water is used to supplement mains supply for domestic hot water. This is equal to a reduction of 40% in the total runoff from the site to the council system. A wet downpipe system eliminates the need for any pumping to the tanks. The rainwater is sterilised and pumped to two domestic hot water plants to supplement water supply. Water efficient fittings and fixtures are specified to minimise water consumption. Landscape treatments are used as a natural filter for stormwater. Minimum AAA water efficient fittings are used throughout. Water meters are installed in each unit to monitor water consumption and collect information centrally for educational purposes. Grey water is collected from buildings 3 and 4 and treated for reuse in toilet flushing and garden watering. Water smart landscaping principles include the use of hardy native plants, planning to maximise water filtration, mulched garden beds with no lawn, and a water efficient drip irrigation system. Water Systems Water Efficient Fittings minimum AAA water efficient fittings throughout Water Storage roof water storage tanks with downpipe system that eliminates pumping Water Smart Landscaping landscape treatments are used as a natural filter for stormwater, together with hardy native plants, bioswales and water efficient drip irrigation Water Recycling treated grey water reticulation supply system recycles water for irrigation and toilet flushing
12 Department of Human Services - Office of Housing Energy Photovoltaic (PV) and flat plate solar collectors are located on the north facing roofs and pod facades. The flat plate solar collector array has been sized to achieve at least 50% of the domestic hot water demand, with the 130m 2 collector area determined by balancing practical considerations of available roof space and system cost. Efficient lighting systems, individual metering and energy efficient lifts contribute to reduced overall energy consumption. The photovoltaic panels contribute 10% of the base building load. Solar hot water flat plate solar hot water panels to pod roofs of buildings 1 and 3 Energy generation and use Photovoltaic and solar panels to pod roofs of buildings 2 and 4 and to pod mansard roofs 3 4 Energy efficient systems efficient lighting systems, individual metering and energy efficient lifts reduce overall energy consumption 2 1
13 Department of Human Services - Office of Housing Landscaping The design of the key public spaces and connections was developed with unique, practical and cost-effective environmentally sustainable landscape design. The gardens link to the buildings and systems via reuse of treated grey water for irrigation and initial stormwater absorption. Approximately 20% of the site coverage is dedicated to soft landscape treatment and planting. Some of the hard surfaces and paving is porous and others drain to collection points on site. The design of bioswales and inclusion of a gross pollutant trap act to filter stormwater before discharge from site. A variety of planting was chosen to suit the varying solar access across the site and includes deciduous and evergreens for passive solar or screening capabilities. Factors such as ability for water uptake, robustness in a densely populated urban development, aesthetic qualities including colour, flowering season and form and provision for biodiversity and habitat were taken into consideration.
14 Department of Human Services - Office of Housing Facts & Figures Anticipated Energy Consumption Per Unit Electricity Depending on ongoing tenant education and choice of appliances, is estimated to be about 550 megawatt hours/year, a probable saving of approx. 55% or 716 tonnes of CO2/year over a standard development. This includes base building and tenant appliances. Photovoltaics Photovoltaic panels on the roof supplement 10% of the base building load, or 25 megawatt hours/year of base building energy which equates to 33.5 tonnes CO2/year. Gas The annual estimated gas energy saving from the solar hot water system is approximately 15 gigajoule/year. Estimated energy saving of approximately 46%. Estimated energy consumption of solar/gas hot water, (assuming educated use and inclusion of water saving fittings to reduce general water consumption) is 103 megawatt hours/year. Landscaping Most of the shrubs and groundcovers used are indigenous to the region and are typically shade tolerant species. Most of the trees used are smaller, exotic cultivars that were chosen for amenity and productive gardens. Estimated water consumption saving of 68%.
15 Department of Human Services - Office of Housing Facts & Figures Anticipated Water Consumption per tenant Water Typical daily water use of a standard apartment is assumed to be 250 litres/person/day. The potential reduction in mains water consumption for the K2 for the total development, over a standard development, is 53%. This is through use of water efficient fittings reducing consumption by 28%, rainwater collection an additional 8%, wastewater reuse for toilet flushing an additional 14% and irrigation 3%. Saving of approx. 44% per person per annum (excluding landscaping).
16 Department of Human Services - Office of Housing Project Details Location Raleigh Street, Windsor, Melbourne. Developer The Department of Human Services, Office of Housing, Property Services and Asset Management. Architect DesignInc Melbourne Builder Hansen Yuncken Site Area: 4,800m 2 Site Content: 96 units, community room and 52 car parks. Cost: $32.3 million Completion Date: February 2007