Your Development

Buildings and dwellings that are designed to respond to climate and use passive heating/cooling rely less heavily on mechanical means to maintain comfortable habitable conditions. Similarly, the clever and appropriate use of features such as vegetation and water in landscaping both internally and externally, shading, materials and colour selection, building orientation and location of open spaces/places may also have a significant impact on the microclimatic conditions within urban developments.

This section deals with a number of areas related to microclimate and how to influence it in urban development, including:

• Designing and constructing developments (buildings and dwellings) to be climate responsive, to reduce the amount of energy required for (mechanical) heating and cooling;
• Encouraging public use of places and spaces through climatic influence;
• Incorporation of development designs and layout which fit with the existing landscape, rather than requiring major intervention,
• Specification of building envelopes to reduce clearing,
• Utilising the natural landscape and features in design, building design appropriate in scale and form),
• Use of vegetation in building - green roofs, green walls, as well as stormwater water management and treatment,
• Use of landscaping for local microclimate influence,
• Urban heat island - impacts and amelioration,
• Use of water in landscaping and buildings (open areas, atriums, etc) for cooling influence.

In working towards more sustainable urban developments, the intent should be for lot layout and design, buildings and public spaces, to be responsive to rather than imposed upon the natural environment.

Accordingly, the design of homes, buildings and open spaces should benefit from opportunities to appropriately incorporate and influence local microclimate.

Design for cooling

• channeling natural ventilation/prevailing (summer) breezes into buildings and homes, courtyards and public spaces
• minimising indoor heat gain resulting from exposure to eastern and western (summer) sun by limiting solar penetration into homes and buildings on eastern and western facades
• using external water features/green walls (vegetated) for microclimate control through evaporative cooling
• using materials with high thermal mass to maintain cooler indoor temperatures
• providing shading/landscaping/tree planting throughout the urban environment, in outdoor spaces, exposed areas (e.g. carparks), and along streetscapes to minimise heat gain in summer, and provide shelter from wind and rain.

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Design for (passive) heating

• orienting buildings and homes as much as possible to benefit from passive heating (solar penetration) in winter, when the sun sits lower in the sky,
• using building materials with appropriate thermal mass for the project’s location, able to capture heat gained through the day and re-radiate it into spaces at night.

Actively designing to create an environment which maintains conditions in the development within human comfort range, without reliance on additional energy use for heating and cooling, saves costs and encourages people to use and enjoy the urban environments we create.

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Building design for climate

More efficient use of energy in buildings will in the long-term help reduce greenhouse gas emissions and global warming. Incorporating elements of passive building design (i.e. orientation, passive heating and cooling, insulation, and shading) is the first step towards achieving a sustainable building, and can provide significant environmental and monetary benefits by reducing the need for energy and costs associated with the operation of mechanical heating and cooling.

Building designs for residential dwellings and commercial buildings should respond to local climate conditions and incorporate passive design principles, to achieve maximum levels of indoor comfort and energy efficiency.

The basic principles of climate responsive, passive design can achieve energy efficiency through maximising natural ventilation and solar penetration though orientation, reducing the need for artificial heating/cooling and artificial lighting. These principles include:

• Orienting the long axis of buildings east-west to maximise (true solar) northern exposure (for natural light and winter warmth;
• Orienting natural ventilation, windows and passageways wherever possible to encourage flow-through by prevailing breezes;
• Locating bedrooms facing south if possible, to reduce additional solar (heat) loading;
• Locating operational (residential living, office areas and entertaining) areas to face true solar north with north-facing windows to receive winter sun;
• Locating outdoor areas such as patios, podiums and courtyards facing north to take advantage of winter sun;
• Locating non-habitable areas such as bathrooms and laundries in residential buildings and building services should be located on the western or southern side (it is preferable to maximise natural light to active areas rather than utility areas);
• Using a choice of lighter coloured materials/finishes including roof materials and on exposed eastern/western walls, that are subject to morning and afternoon sun to reduce heat gain;
• Providing shading by eaves, external screens and overhangs on east and west facing walls and windows to block summer sun (higher in the sky) but potentially allow entry of winter sun (lower in the sky); and
• Maximising opportunities for cross ventilation by careful design, location of rooms, and placement of windows and doors.

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Outdoor environments and microclimate

Designing for microclimate delivers development forms which seek maximum benefit of natural breezes, and positive influence on microclimate through retaining natural vegetation – particularly large shade trees, landscape planting and vegetated landscape features such as green walls, street trees in plaza/public spaces and using the natural cooling effects of wind moving over water to positively influence microclimate.

Similarly, consideration of local microclimate during design should be used to minimise the effects of wind ‘channeling’ through enclosed urban spaces - this is potentially an issue in winter with funneling of breezes resulting in chilly urban spaces, particularly where there is predominant shade and limited winter sun. Combined with designing for effective ventilation, locating development features so they gain benefit from winter sun and avoiding locating tall buildings and structures so that they cause overshadowing can help to encourage a more comfortable outdoor environment around and between buildings.

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Case Study – Viret, Clayfield, Brisbane

The vision for Viret, developed in Clayfield, Brisbane by QM Properties was to create the most natural and livable apartment development possible whilst minimising the impact on the environment. Special attention was paid to detail in the design and the result is the ultimate in indoor/outdoor lifestyle, perfectly suited to the south east subtropical Queensland climate.

Viret was undertaken working closely with Brisbane City Council during the design process, resulting in it becoming the first apartment development to be approved by Council’s Sustainable Design Unit.

Design features include:

• 14 exclusive, 2-bedroom, 2 bathroom, air-conditioned apartments in a modern, sub-tropical design;
• Development design undertaken by a leading architect in Ecologically Sustainable Development (ESD) to achieve up to five star building energy efficiency;
• Large, livable balconies with timber framed bi-fold doors that slide away to combine indoor and outdoor spaces;
• All apartments face north to maximise natural light and cross ventilation;
• High ceilings to encourage ventilation and circulation;
• Materials and finishes selections based on livability, durability and minimal impact on the environment;
• Apartments in Viret feature a unique ‘breezeway’ designed to maximise natural light and ventilation. The inclusion of breezeways gives each apartment three active facades, a unique feature in multi-storey developments. The benefit is natural climate control all year round and light, airy living spaces.

Other sustainability features include:

• rainwater harvesting and re-use within the building
• solar panels for energy conservation allowing residents to reduce their power bills
• AAA rated tapware
• natural vegetation retention onsite
• low toxicity and embodied energy building materials and finishes
• recycling stations and
• materials selected from sustainable sources.

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Key Issues

Benefits

Design for microclimate through encouraging natural ventilation for heating and cooling (in preference to a closed home with mechanical ventilation), encouraging breezes through outdoor spaces, and allowing natural light penetration into indoor spaces saves costs associated with energy use (for heating, cooling and lighting). Further, climate responsive design is being increasingly recognised as providing other benefits such as indoor ambience, outdoor amenity, and genuine health benefits to the occupants and users of well designed buildings and spaces.

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Risks

While not really able to be considered as a development ‘risk’ it is important to recognise the inherent trade-off between design and development costs which may accrue at the beginning of the project, with improved energy/environmental efficiency and consequent running cost savings accorded by the climate responsive design approach.

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Savings

Savings resulting from climate responsive design will largely be from reduced energy use (within buildings/dwellings). However, cost benefits will also accrue from a more comfortable development product.

Development elements which contribute to positive microclimate influence also provide visual amenity – shade trees and landscape vegetation, water (ponds, streams, etc), green walls and use of vegetation in indoor spaces. These elements can assist in making a development more sellable – offsetting possible increased project costs with increased return on sale or lease rates.

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Costs

When considered as part of the full development life cycle/feasibility assessment, good design should not cost more. It is acknowledged that there are inherent trade-offs between a more detailed (and potentially costly) design stage and development costs which may accrue at the beginning of the project, with improved energy/environmental efficiency and consequent running cost savings accorded by the climate responsive design. However, good design for microclimate will ultimately cost less than poor design in the long term because it reduces the likelihood of needing to redesign/retrofit poorly designed or badly performing building elements at a later stage.

There may be other additional costs associated with the initial stages of development – in particular site choice. Premium sites with optimum amenity, topography, vegetation, etc will always cost more than less attractive sites. Direct costs may also be associated with:

• Potential increased time in design stage to ensure a more considered approach;
• Additional costs incurred during development until such time as sustainable development becomes more recognised as mainstream development with a difference.

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Barriers

There are in effect nil physical barriers on the ground. There are however, barriers in the perception and acceptance of passive design principles as being equally important as providing floor area and development yield. Consequently, barriers can be minimised or avoided when the project team (including project managers, and relevant internal stakeholders) have sufficient understanding, experience, capability and sensitivity to environmental design, so that issues are carefully considered throughout the design process. Specialist advice may therefore be beneficial in ensuring the project team has a proper understanding of principles and application of design for microclimate for the development project (in contrast to ‘business as usual’ development feasibility analysis and planning). For instance, the Green Building Council of Australia ‘GreenStar’ tools apply points for having a ‘GreenStar’ Accredited Professional on the project team from the outset.

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Benchmarks

Nil benchmarks specific to design for microclimate, however effective design for climate can contribute to buildings meeting requirements under relevant building energy ratings systems (eg. BERS, NABERS, BASIX). The use of effective design for microclimate benefit will contribute to buildings/dwellings achieving potentially higher energy performance ratings than developments that do not seek to incorporate microclimate benefit.

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Development phase actions

Feasibility

A detailed feasibility analysis and site selection should include consideration of the following:

• site topography, aspect, elevation,
• local microclimate, including rainfall, local winds, and
• climatic influencing factors – vegetation, waterways, large water bodies.

Specifically, the type of climatic information (readily available from the Australian Bureau of Meteorology – www.bom.gov.au) likely to be sought is as follows:

• daily summer/winter temperatures range
• mean temperatures:
• winds: summer; winter.
• summer extremes:
• winter extremes:
• prevailing breezes: morning, afternoon
• average annual sunshine (hours): summer; winter, sun path diagrams (see also Your Home Technical Manual for regional sun path information).

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Planning

The planning and design phase will involve a more detailed consideration of factors identified during the feasibility study:

• consider implications of site investigation
• development opportunities and constraints analysis
• design of development form to match topography and environmental features (vegetation, waterways)
• urban design
• identification of movement corridors (environmental and activity)
• consideration of microclimate characteristics (as identified above)
• orientation of development allotments and streets, buildings and structures in accordance with passive design – orientation, breezes, aspect, slope, etc.

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Construction

Construction methods, site works and landscaping, choice of materials and finishes in buildings and structures is crucial to ensure the design intent (of climate responsiveness/positive microclimate influence) is carried through. Key elements include:

• material selection - choose materials which are appropriate for the relevant climate zone for the project. Choice of materials will vary according to the predominant climate conditions, and the degree of daily/seasonal variation (see also Your Home Materials for more information).
• housing and building design and construction should be undertaken consistent with energy efficiency principles relevant to climate. As a guide:
  • tropical/sub tropical climates - light weight (low thermal mass) construction;
  • hot/dry (warm summer) climates - passive solar design with insulated thermal mass (eg concrete, rammed earth, stone) for cooling;
  • hot summer/cold winter climates - passive solar design, well insulated thermal mass, well insulated building fabric;
  • temperate (warm/cold) climates - passive solar design, well insulated thermal mass.
• surfaces and reflectance - light coloured surfaces will reduce heat gain - dark coloured surfaces retain heat. These principles can be used to improve passive heating/cooling for both indoor and outdoor environments, when combined with passive/solar design principles.
• use of vegetation and shading onsite:
  • providing shelter from summer sun and rain,
  • encourages use of outdoor spaces, and improves indoor environments (air quality, ambience, and evaporative cooling); and
  • vegetation provides evaporative cooling during summer, provides opportunities for retention of water in the landscape, and reduces the extent of 'urban heat island' effect.

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Completion

Following completion of the development project, it may be beneficial to undertake a process of education and marketing to potential purchasers, and development users on the use of passive design and building/construction to influence/benefit from microclimate. Industry representatives may also use this type of information as a way of demonstrating to the development industry the application of passive design.

Users should be informed of development features to ensure that their ‘use’ of buildings and dwellings is consistent with the inclusion of sustainability:

• making use of passive design features instead of reliance of mechanical HVAC;
• provide details of landscape elements and microclimate influence;
• explanation of materials and colour choice for microclimate influence, to guide any future refurbishments.

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