Surry Hills Library and Community Cennre — so how does it work?

The fundamental objective of the Surry Hills Library and Community Centre was to focus on the wellbeing of occupants and users. The constrained site led the design team to develop innovative approaches to space utilization that also answered the complex and extensive functional and user brief requirements. Opportunities were seen in using passive, hybrid and multifunctional systems and in drawing inspiration from natural organisms that have adapted and evolved in response to the specific resource availability of their environs.

The project integrates a number of elements that not only draw upon these natural systems but directly utilize them to improve the internal and external environment and thereby occupant physiology.

The resultant design approach refers to a number of sustainable design concepts:

• “Cradle to cradle.” William McDonough’s concept of taking nature itself as our model for making things, as well as pursuing the ideal of being environmentally “good” rather than just “less bad.”
• “Biomimicry.” Buildings and systems that emulate nature to provide suitable environments or structures in a sustainable way.
• “Positive Development.” As discussed by Janis Birkeland in her book Positive Development: From vicious circles to virtuous cycles through built environment design.

As concepts such as these begin to permeate the industry, it will be critical to record, analyse and publish definitive scientific data. With this in mind, the City of Sydney has committed to reporting the performance of the Surry Hills Library and Community Centre to both the industry and community.

One of the building’s major systems of interest is the environmental atrium, which combines a primary facade with the integrated “respiratory system” of the facility. This perhaps transcends the modernist “building as a machine” metaphor to become not quite a living body, but a closer imitation and simulation of biological and organic models.

Thus the building can be seen as having not only an external skin and a structural skeleton, but also a system of conduits that transfer oxygen, energy and sensate information to other nodes, while using the power of the sun, the water from rain, the heat of the earth and oxygen from photosynthesis to help sustain the occupants.

System description

Even though the overall system works collectively in its use of passive, active and organic elements to provide an improved condition and quality of air to the interior, the component parts can be described as follows.

1. As in most respiratory systems, the point at which the air enters provides primary filtration and tempering. The air intake has been located as far above street level as possible to reduce the burden of pollutants from traffic and passers-by. It is also orientated to benefit from the natural driving force of the prevailing wind (N/E) to overcome resistances that, in turn, reduce reliance on mechanical systems. The intake is protected from ingress of rain and integrates the first stage of particulate filtration. The intake naturally tempers the air as it flows across a water-to-air heat exchanger coupled to five geothermal bores which draw energy from the earth (100 metres deep) to heat cold air, or cool hot air, as needed.

2. The tempered air is drawn down the building through the southern double facade, which helps to “cocoon” the body of the building from the outside, even though the facade is transparent (providing connection between the interiors and the external park and vice versa). The transparency and connection further benefits from the southerly orientation (not requiring shading devices) and the planting, which, together with bedding biomass, provides the second stage of air filtration and the key to air quality improvement – the bio-filtration process, whereby the plants and biomass help to reduce external pollutants as well as increase oxygen levels. Air quality was a key initiative due to the nature of the building, which is used not only as a library and community centre (where occupant alertness can aid learning) but also as a childcare facility where the health of the community’s children is of utmost importance. This is a key area of research, because even though there is general consensus that many plants are effective in improving air quality, actual quantified data is not readily available.

3. The next stage is more conventional, with a further fine grade of air filtration and in-line fans used to help drive the air. Even though these fans use electricity, an array of photovoltaic cells mounted on the roof have been included to offset the power required for this part of the system (as well as the geothermal pumps used to temper the intake air). However, in line with the multifunctional approach of most parts of the system, these PV panels also shade the external airconditioning heat exchanges from the sun, thereby increasing their efficiency.

4. The air is then directed through the thermal labyrinth. This is another multifunctional element – the basement library/learning resource area has a “wet wall” and, as such, required an accessible double wall arrangement. This inherent void was used to distribute air to various points and, together with a simple, staggered, thermally massive masonry arrangement, provided further passive tempering of the air while also reducing the need for any extra space and costs associated with distribution ductwork.

This labyrinth element is “recharged” when needed via a night purge cycle, which benefits from diurnal conditions by storing coolth in the thermal mass for use during the day. The night purge cycle also helps to disperse the plants’ natural cycle of releasing CO2 at these times and removing any humidity created by the after-hours irrigation system.

5. From this point some air is delivered directly to a portion of the building, while the areas that can benefit from a “hybrid” or “mixed mode” ventilation approach are supplied with air that passes through a second stage of bio-filtration (further filtering and oxygenating the air). This air is delivered via alternate “cells” in the southern facade, again helping to cocoon the building, and this purified/high-quality, naturally tempered air enters the occupied zones (including the community and childcare centres) through floor grilles that are positioned to aid cross-flow and buoyancy-driven ventilation, which satisfies the majority of requirements during the year.

As these hybrid systems become more popular and occupants become more aware of how they work and how they can be “worked”, they will be prepared to accept slightly wider temperature bands, which, in turn, reduces the impact on the environment. For occasions of higher than normal internal heat gains or extremes of external conditions, the air is simply redirected to low-energy, zoned VRF airconditioning units.

6. Architectural finishes and fixture selections were carried out to complement this approach to improved air quality, with low-toxicity and low-VOC materials being specified throughout. This supports the mantra of “first do no harm”, which should be the norm, especially in community or healthcare environments.

This design objective was realized earlier than was first envisaged.The contractors acknowledged the improved indoor air quality during construction, when the typical “new building smell” was essentially non-existent.

7. Finally, the air is predominantly naturally relieved from the building at high points within transitory zones with the assistance of buoyancy, wind and solar power.

Wider benefits

This core initiative has had inherent complementary benefits:

• Conservation of energy. Other than the passive and hybrid systems, on-site renewable sources such as the photovoltaics and use of geothermal energy are supported by the residual energy needs being satisfied by off-site renewable energy purchase.
• The optimum system arrangement and integration of multifunctional systems provided substantial initial cost and space savings, with a number of alternative arrangements and environmental initiatives assessed at the time.
• Expected psychological benefits of being in a building where you can see and learn about the environmental initiatives. Even subliminal characteristics, such as air passing across the plants making the leaves move, further blur the lines of interior and exterior and have been noted as attracting a positive response from occupants.

The preliminary results are showing that the building, in the early phases of occupation and commissioning, is performing well in terms of energy, water and gas use. The outcomes have either matched or bettered the predicted outcomes established in the detailed modelling. The figures above address results for November 2009 (a month that proved hotter than the norm) in comparison to an “average” performing building and against a “benchmark” building from the City of Sydney that has been suggested as representing the best performing asset in the property portfolio at the time of design.

Read Laura Harding’s review of the building from this issue of Architecture Australia.