It can be argued that industry’s use of computer simulation has not kept up with the potential contribution this technology can make to the design and construction of buildings.
We use the visionary South Australian Health and Medical Research Institute (SAHMRI) building as a case study of how dynamic thermal simulation (energy modelling) and daylight simulation methods can be optimally applied to enhance the environmental performance of a new building.
Computer simulation of a building’s environmental performance typically embraces three related but separate applications:
Simulation is most commonly used for National Construction Code (NCC) and sustainable rating tool compliance.
In theory, simulations of this type can provide significant value to projects by freeing the designer from the constraints of Deemed-to-Satisfy (DtS) processes within codes and standards.
In practice, much of this potential value is lost because the analyses are undertaken well after the major design decisions have been made. The work becomes merely a validation of existing design rather than a tool for innovation or optimisation and fails to capture the full value of simulation.
The largest opportunity for built-environment designers is to use simulation to compare design decisions and opportunities during concept design. This requires buy-in from the whole design team, not just architects, in order to reach a common optimised goal.
Preliminary analyses can be used to inform key design decisions e.g:
There are many software tools that can be used in early modelling.
Figure 1: Opportunities for the use of simulation throughout the design and construction process
In design development, simulation has a myriad of uses informing the decisions of architects and engineers. Key opportunities include:
In construction documentation, the opportunities for changing design have largely passed, but simulation can still continue to add value through:
The use of simulation in post-construction performance verification is increasing, providing opportunities for improvement in control commissioning, tuning and modelling.
Figure 2: SAHMRI completed facade showing hood geometry
Although still not commonplace, a performance-based approach to simulation in the early building design stage can have impressive results. SAHMRI, and in particular its striking facade solution, is a product of performance-based design that balanced aesthetics, cost, and buildability, as well as environmental variables such as solar control, daylight availability, glare and thermal comfort.
SAHMRI is a 25 000 m2 research facility. Its design team included Woods Bagot, Atelier Ten, Cundall, NDY and Aurecon.
Key to the success of the design was developing quantifiable performance metrics upfront to allow robust testing of options between the environmental design consultant, Atelier Ten, and architect, Woods Bagot.
Fig 3 summarises the metrics and outcomes that could be impacted by the facade alone:
Figure 3: Impact of facade on building performance
The first step of the facade optimisation process was to assess which space type required access to daylight and which spaces lent themselves to opaque elements. With the three-dimensionally curved form of the building and significant facade structural spans across multistorey atria, a triangular grid-shell solution was selected as the most appropriate facade system. Nine variations of exterior shading devices were simulated.
Regardless of the space type selected to sit behind a particular piece of facade, limiting direct solar gains was crucial in reducing HVAC plant size, energy consumption, risk of glare and improving thermal comfort.
However, the value of the simulation was in freeing the designers to select an external shading strategy optimised for cost and buildability rather than purely for energy savings.
With the facade significantly affecting thermal comfort, daylight and glare – the performance discussion focused on making an attractive, healthy workplace ‒ the Wellness factor for the occupants of this visionary building.
Computer simulation gives design teams the opportunity to test building performance during the design process through to post construction. Correctly used, a simulation can return many times its cost to a project. However, often simulation is used purely for compliance with NCC JV3, Green Star or NABERS; this undervalues the simulation and wastes much of its value potential to a project.
Design teams should use simulation as an integral part of the design process to enable better design decisions to be made throughout the entire construction process.
About the authors
Nicki has recently taken up the position of Norman Disney & Young’s Sustainability Manager for Brisbane after an 11 year career in building physics and sustainability.
Quentin is an Environmental Modelling and Sustainable Design specialist and leads Aurecon’s Sustainability team in Queensland.
Dr Paul Bannister
Dr Paul Bannister is Director of Innovation and Sustainability at Energy Action. He is an internationally recognised authority on energy efficiency in commercial buildings and is the primary technical author of the NABERS Energy and Water ratings systems.
Managing Director of Atelier Ten’s Australia offices, Paul Stoller is recognised for environmental planning and design consulting work on large-scale campus, community and urban building projects.