International Cities Town Centres & Communities Society
ICTC2011 Grand Chancellor Hotel, Hobart, Australia 25 – 28 October, 2011
A Case for Affordable, Green and Healthy Community Buildings Charles Nilsen (1) Manager Urban Design + Architecture, City of Monash/Australia Phone + 61 3 95183425 & Fax No 61 3 9518 3444; email email@example.com
ABSTRACT This paper, which is based on a recently completed innovative Community Hub, presents an illustrated case study of a “green” and affordable community hub that has been designed to achieve a 5 star NABERS rating for in-door air quality, energy efficiency and water conservation at a capital cost equivalent to conventional buildings. The paper presents an analysis of the planning and design process, as well as the design elements that have contributed to a very innovative, affordable, sustainable community facility and a healthy working environment. The paper also explodes the myth that “green” costs more. The building does not employ conventional air conditioning and the analysis will include human comfort parameters. The building is a response to a needs analysis undertaken by the local community. The resulting 1200 square meter building provides a multi-function hub for five  resident community groups and agencies, as well as facilities for non-tenant community groups. The building has already been adopted as a template for similar developments by other communities and municipalities. KEYWORDS: Ecologically Sustainable Design [ESD], community hub, enhanced passive design, water sensitive design.
1. INTRODUCTION The Batesford Community Hub is located in the City of Monash in the suburb of Chadstone, 12 kms south east of the Melbourne Central Activity District. The surrounding Chadstone Ashwood area is regarded as socially and economically disadvantaged with many households experiencing some form of hardship or dysfunction. A community Neighbourhood Renewal program identified the need for a multi-function Community Hub. The planning and design of the Batesford Community Hub was the result of collaboration between the six  community stakeholders to be located at the community hub, council’s Community Planning department and council’s Urban
Design and Architecture team. The Hub provides accommodation and facilities for Monash Youth and Family Services, MonashLink Community Health Service, Berrengara School VCAL Program, Ashwood Chadstone Tenants Association, U3A Waverley, as well as computer laboratory facilities for two  local neighbourhood houses and community meeting rooms. The design process included regular design meetings and briefings with the community stakeholders. In the very early stages of planning and design it was determined that the proposed Hub should be both energy and water efficient, as well as providing a healthy indoor environment with a high level of occupant user control over comfort. The product of the design and construction process has been a very innovative and ecologically sustainable building that has met all of the userâ€™s functional requirements as well as their requirements for a very â€œgreenâ€?, yet comfortable building. The energy efficient design is based on sound passive design principles; good cross ventilation, excellent day light to all spaces, summer sun control, access to winter sun, high standard insulation and use of thermal mass internally. This has been enhanced by an innovative use of a tempered air system to achieve acceptable levels of occupant comfort. The built result demonstrates that sound ecologically sustainable design [ESD] can deliver a healthy, energy and water efficient built environment at a cost that is comparable to conventional buildings. The paper describes and illustrates the design process and principles, as well as giving aa candid analysis of the design and built outcome, including lessons learnt.
2. BACKGROUND The need for a multi-function Community Hub to house a number of community agencies and provide local support programs was identified by a community Neighbourhood Renewal program, which had been established by the Victorian Government Department of Housing with support from the Victorian Department of Human Services [DHS]. This lead to a feasibility study which was funded by DHS The feasibility study included a substantial consultative process with community stakeholders and potential project partners to establish a project brief. This process also identified the agencies that could deliver support services, which would be of greatest benefit to the local community, as well as identifying synergies between agencies. The feasibility project brief provided the basis for a concept design and development feasibility for the identified site. The feasibility study enabled a successful application for federal and state government funding. The design and construction was managed by council and council provided the land. While Council contributed $120,000 to the design of the project, the balance of the $6.1m budget was externally funded. State government funding partners included the DHS and Office of Housing Neighbourhood Renewal.
3. PROJECT DESIGN OBJECTIVES The following design objectives were agreed between the community stakeholders and project design team at the commencement of the design process: • A low ecological footprint • A high standard of energy efficiency and Ecologically Sustainable Design based on best practice passive design. • As built 6 star Australian Green Building Council Green Star or 5 star NABERS performance. • A comfortable and healthy indoor environment based on a high standard of air quality. • Affordable and comparable cost to conventional public buildings. • An attractive, convivial and welcoming community environment. A low ecological footprint was to be achieved with energy efficiency, water conservation techniques and sound passive design of the building envelope. As there was no Green Star rating tool for community and public buildings at the time, it was determined that the NABERS rating tool would be used. This had the advantage that indoor air quality would also be measured, as the Green Star rating system does not take air quality into account.
4. ECOLOGICALLY SUSTAINABLE DESIGN [ESD] PRINCIPLES The principles of ESD are underpinned by best practice “passive” solar design techniques that have been employed to achieve a high standard of energy efficiency and occupant comfort, and to minimise green house gas emissions, including: • optimum solar orientation to maximise winter sun penetration into the building, and maximise use of daylight. • sun shades to control summer sun, • a well insulated building envelope with double glazed windows in timber frames, • maximising daylight to all internal spaces, including the use of solar tubes. • maximising natural ventilation and cross ventilation with openable windows and sub ground floor inlet cool air for warm season comfort, • use of thermo-siphon to maximise natural air movement and cooling, • maximum use of internal thermal mass, This is enhanced by the building being dug into the natural topography and partly buried. The passive design has been enhanced by a number of innovative active design techniques including: • A sub floor labyrinth to supply tempered air, • The use of thermal chimneys and automated openable windows and skylights to facilitate the thermo-siphon effect and night purging. • An evaporative cooling system for the limited number of occasions when additional cooling is required to maintain occupant comfort. The evaporative cooling system is designed to imitate the natural cooling system with cool air delivered close to floor level and the warm air exhausted near ceiling level.
Figure 1, Passive Cooling
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Figure 2, Passive Design
A 13.5 Kw grid interactive photovoltaic solar array to provide at least 60 % of the power required and sell excess power to the grid. With user education and good management it may be possible to break even. Movement activated and photo sensitive internal and external lighting. Dimmable lighting to take advantage of good daylight levels. T5, compact fluorescent and LED energy efficient lighting systems.
Figure 3; Solar Panels & Sky Lights
Figure 4; Thermal Chimneys & Sun Hoods
The innovative design is further enhanced by: • the use of sun hoods to control penetration during warmer months, • light shelves on the north elevation to facilitate greater daylight penetration. • Exclusion of west sun. The west ground floor is also shaded by rain water tanks. A building management system has been employed to optimise the automated elements of the building design. This controls the automated opening windows, the gas heating, dimmable lighting, mechanical ventilation and evaporative cooling, and the security system. When the security system is activated the other mechanical and lighting systems are shut down with the exception of the night purging system. 95,000 litres of harvested rain water is used to flush toilets and urinals, top up the evaporative cooling system and make the building drought proof. Some of this water will be utilised to establish a community garden on the site. Excess rain water overflows from tanks into swale drains and gardens to charge ground water. Rain gardens and a bio-swale remove pollutants from storm water before discharging into
the storm water drainage system. A drought tolerant plant palette has been utilised to enhance the site and eliminate potable water for irrigation.
5. DESIGN PROCESS The federal governmentâ€™s funding conditions included the time frame for the delivery of the project, which meant that the project had to be designed and documented in less than six  months. This is approximately half the time that would be allowed for a project of this nature and required a very disciplined approach to both the stakeholder consultation and the design management. 5.1 Consultation and Engagement
The design process involved design and briefing meetings every two  weeks with the proposed users and stakeholders. This group had indicated that they favoured a â€œgreenâ€? building. One of the first issues to be addressed with this group was the issue of air conditioning. It was agreed that air conditioning, and in particular reverse cycle air conditioning, would not be utilised as this would dramatically increase power consumption and, consequently, green house gas emissions. Had air conditioning been utilised the modelling analysis showed that it would have accounted for 80 to 90 % of the power consumption for the building. The user group wanted to ensure that occupant comfort would also be of a high standard, but agreed that the internal comfort conditions could vary from 19oC to 25oC. This meant that users also accepted that they would need to dress according to the seasons rather than expecting a constant internal temperature of around 22oC. Research indicated that human comfort, particularly for sedentary occupants, could be maintained up to at least 26oC in a temperate climate and this can be enhanced with ceiling sweep fans to gently move air. The stakeholder group also wanted to maximise renewable energy. Consequently, when the construction tender came in $600,000 under budget the photovoltaic solar power generation installation was increased from 5.5Kw to 13.5Kw, which was the maximum size that could be managed within the available roof area. Similarly, the rain water tank storage was increased to 90,000 litres. This provides at least a three  month supply for flushing toilets and urinals, as well as topping up the evaporative cooling system. 5.2 Peer Review
An innovative and unorthodox element of the design process involved engaging a small team of professionals, led by a scientist, to engage with the design team in two  design review workshops. The main purpose of this was to save time by using the combined experience of the review team to test and review the ESD modelling and solutions proposed.
This process confirmed the proposed passive design approach. However, a proposed shower tower cooling system was assessed as high risk and not viable. Consequently, it was abandoned in favour of more conventional evaporative cooling technology. The design and risk evaluation process also determined that the evaporative cooling units should be located on the south [cool] side of the building and integrated with the building envelope rather than on the roof. This would allow the units to be placed closer to the delivery locations to optimise performance. It also had the added benefits of better maintenance access and maximising the roof area available for photovoltaic solar panels. The peer review process also supported the innovative, but affordable, proposal to introduce “tempered” air into the building from the shaded south side via concrete pipes. The use of concrete pipes, rather than light weight pipes or ducts, to create a labyrinth under the ground floor increased the thermal mass of the system. This supplies fresh air into the base of the building at a relatively constant temperature. Fresh air is either cooled or warmed by 2-3oC [tempered] in the pipe labyrinth, depending on the season, before it enters the building interior. 5.3 Design Research
Despite having an experienced design team research and investigation became a very important factor in identifying appropriate products, materials and systems to maximise performance and affordable outcomes. A valuable on-line source of verified green products is Ecospecifier. While an experienced team of sub consultants was employed, it was often necessary for the architectural design/management team to assess and prove options and proposals. One such instance involved the roof mounted solar photovoltaic panels. Contrary to the sub-consultant’s advice it was possible to increase the size of the installation, from 11.0Kw to 13.5Kw, and the efficiency, by using an alternative panel of the same manufacture, which was slightly larger, but 20% more efficient. Investigation also revealed that the efficiency and output of most solar panels is substantially reduced by shadows, even when the shadow cast on the panel is quite small. By modelling the “angle of attack” [the angle of inclination from horizontal] of panels and the shadows cast it was possible to adjust the spacing between the banks of panels to eliminate even winter shadows. The proposed “angle of attack” was to be 30o. However, the optimum “angle of attack” for year round performance and efficiency turned out to be 20o. 5.4 Materials
Every building element was regarded as an opportunity to utilise green materials. Wherever possible, recycled and salvaged materials were utilised. Consequently, 600 cubic meters of top soil and clean fill was salvaged for re-use on site and for another nearby project. Crushed rock pavement base was also salvaged and reused. Materials and products containing recycled content were preferred. Hence, structural concrete with 20% flyash [waste by-product in power generation] content and carpet tiles with 60% recycled content were used. Recycled bricks were used in the majority of internal walls to maximise thermal mass and minimise embodied energy [the energy required to process and manufacture a product]. Materials like
aluminium, with high embodied energy, were avoided wherever possible, unless there are life cycle advantages. Materials and adhesives that give off volatile organic compounds [V.O.C’s] were avoided. Hence, Marmoleum flooring was use in lieu of vinyl flooring, as were low odour paints and finishes. Products manufactured with toxic materials and heavy metals, such as chromium and cadmium, have also been avoided. The other category of preferred products used is those manufactured from renewable resources, such as timber, bamboo, cotton and wool. Either plantation timber, for framing, or Forest Stewardship Certified [FSC] timbers, for cladding and decking, has been used. Timber framed windows and doors were also used.
Figure 5; Recycled Materials
Figure 6; Sustainable Interor Finishes
6. CONCLUSIONS The conslusions drawn from this project can be categorised as “design” and “project management” lessons. 6.1 Design Lessons
The main lessons have been: • The enhanced passive design with individual occupant control works. • Indoor air quality, daylight and ambience are excellent. • While the day light levels are excellent, automated photo sensitive dimmable lighting is only warranted around perimeter, if at all. • The ground floor common area required heating as it is used more than was anticipated. The retrofitted electric radiator panels have corrected the situation, but have increased the carbon footprint marginally. Gas fired hydronic heating and radiator panels would have been an appropriate solution as flued gas space heaters are not viable. • A subfloor semi-basement labyrinth, in lieu of the concrete pipe labyrinth, would be preferable and easier to maintain. • Engage regularly with users/stakeholders during design and post occupancy. Explain design options and implications for users/occupants . 6.2 Management Lessons
Design and project management lessons include:
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Experienced peer design review can be valuable Be sceptical of sub-consultant advice and test it. At $3,300 / m2 the build cost is comparable to a conventional building of the same size. Power consumption is less than 15 Kw/day. With education and behaviour change power consumption, and GHG emissions, can be reduced. Buildings with technology, particularly building management systems, require tuning for at least 12 months. Pre and post occupancy NABERS 5 star rating assessment measures actual as built performance with respect to indoor air quality, energy, water and green house gas emissions.