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From: AECbytes Viewpoint #54 (July 14, 2010)

Performance Analysis Technology and Radical Design Change for Carbon Neutrality

Dr. Don Mclean
Founder and CEO, Integrated Environmental Solutions (IES)

“Climate change is the greatest threat to our common future. We have a very short period of time to tackle the problem before it becomes irreversible and out of control. A lot of progress has been made, but we must now go further, faster and turn targets into real change.”

- Chris Huhne, Secretary of State for Energy & Climate Change (May 2010)

With climate change so high on the global agenda, few of us need persuading about the importance of sustainable building design. But making it happen is another matter. Unfortunately, it is clear that currently, Green, Sustainable and High Performance Buildings are not going quickly enough in reducing their negative impact on the environment, and certainly not far enough to offset the balance of buildings that march on in ignorance.

The Lean, Clean, Green Approach

Sustainable design is a holistic way of designing buildings to minimize their environmental impact through:

  • Reduced dependency on non-renewable resources
  • A regional response to climate and site
  • Increased efficiency in the design of the building envelope and energy systems
  • Environmentally sensitive use of materials
  • A focus on healthy interior environments
  • Environmentally sensitive construction
  • Meeting the needs of the present without compromising the ability of future generations to meet their own needs

A specific part of this, zero-carbon building design, is all about energy—reducing demand (loads) through climate responsive design, meeting those needs efficiently and effectively, and using renewables to deliver on reduced energy needs. However, it must be ensured that the building offers a healthy, comfortable internal environment. To achieve this, the industry needs to start thinking about the design process in an entirely new way, not just modify current practices.  This is what I refer to as the Lean, Clean, Green approach.

  • LEAN – using good design to make passive and hybrid strategies part of the solution
  • CLEAN – applying low-carbon technologies
  • GREEN – leveraging renewable technologies to a higher degree because the energy requirements of the building are now greatly reduced.

Climate needs to be the starting point—basic building design must be climate responsive, or the passive systems won’t work, and the mechanical systems won’t be small enough to be powered by renewable energy.

In this article I aim to discuss what radical changes need to be undertaken to the design process, changes in mindset required, and the important role Building Performance Analysis software plays in enabling the Lean, Clean, Green approach. Because, as the physicist Lord Kelvin put it, “If you can’t measure it, you can’t improve it.

How Building Performance Analysis Tools Can Help

Passive design uses the sun, wind, and natural light to heat, cool and light the building.  The building architecture should be used first—heat only with the sun, cool only with the wind and shade, light only with daylight where possible—and only then use mechanical systems to supplement what you cannot otherwise provide.  Finally, use renewable, clean energy before hooking up to natural gas, oil, or the regular electrical grid.

As part of this process, there is a general comprehension and growing knowledge of just how powerful building performance analysis tools and energy modeling can be in guiding informed decisions on what strategies will work for the climate, site, and the building in question.  However, there are still a lot of unanswered questions, particularly among architects, as to what this technology is and how it can be used to best effect. 

Questions that are routinely asked include: What analysis capabilities are available to me?  How do the results inform me?  What tasks should I be doing when?  And how do I incorporate all this into my workflow?

Performance analysis is a vital component in designing truly sustainable buildings—creating understanding of the impact of different strategies on energy consumption and other environmental metrics. Building performance analysis software allows designers to “virtually” test the feasibility of different energy saving strategies and new technologies and facilitate low-energy/low-carbon designs. It can help not just during the design phase but also during the post-construction occupancy phase as well, as shown below.

Building performance analysis allows companies to achieve cost effective and increasingly more efficient environmental performance, while also enhancing competitive advantage, through a shift from the conventional linear building design and delivery processes to a multi-disciplinary practice of interrelated systems integration at the whole building level.

“An integrated design approach is required to ensure that the architectural elements and the engineering systems work effectively together.” IPCC report “Climate Change 2007”

You will have probably noticed that integrated design is a recurring theme at the moment across BIM, other CAD tools, and processes such as Integrated Project Delivery (IPD).  This integrated information sharing approach to design team working is one of the key changes to current thought processes that needs to take place. This integration, in conjunction with a greater understanding of climate-responsive Lean, Clean, Green design, makes it possible to achieve significant energy and carbon emission reductions in buildings.

Starting Early with Building Performance Analysis

Many key decisions that affect a development’s sustainability credentials, such as orientation, layout, form, envelope and potential passive strategies, are taken right at the very early stages of the project.  As a consequence, designs are often fully developed architecturally before the impact on sustainability issues is even considered, by which time, the opportunity to make a difference has passed. Addressing these issues and getting sustainability on the agenda right from the beginning has to be a key priority if the industry really wants to embrace sustainable design. 

Unfortunately, the same is also often true of Building Performance Analysis—too often, modeling is undertaken at the later stages of design as part of compliance and not incorporated into the process right from the start where it can make the biggest impact.

A change in mindset is required; performance analysis needs to come out of the back room and into the forefront of sustainable design—from the hands of a few into the hands of many.  It needs to be incorporated at the right level across the whole design process—from comparative ballpark, apple with apple comparison right at the earliest stages, through to more detailed analysis and compliance at later stages.

Comparative analysis of climate, building metrics, solar, energy/carbon, light and natural resources at the early stage, using ballpark figures, can be useful to check feasibility, quantify and inform design team decision making. It can help with those all important master-planning, orientation, massing, and form decisions, justifying choices and differentiating project proposals.  Results can be used to explain and quantify to clients the sustainable impact of different decisions and tradeoffs, offering a competitive advantage. Also, feasibility conversations with engineers can easily be started early on before key decisions are set in stone.

Detailed analysis of these and other elements such as airflow, thermal comfort, heating/cooling loads, egress and value/cost at later stages provides more accurate figures and results for system sizing, fine tuning, compliance, costing, and documentation. Again, competitive advantage is achieved as results and analysis can be presented to clients and building control, justifying design decisions and providing data for effective commissioning and in-use operation.

Here are some questions that analysis can help answer throughout the design process:

From the examples above, it is obvious that such conceptual differences cannot be bridged with simple file compatibility no matter how perfect the interface is. The real solution is to build dynamic round-trip collaboration workflows, where each component of the workflow is specifically prepared to fulfill the different workflow requirements. Let us explore such an “open” IFC-based collaboration workflow between the architect and the structural engineer by discussing the specific requirements for each component.

The Importance of Cross-Disciplinary Collaboration

Such a holistic approach to sustainable design requires the greater collaboration and integration between all parties that we touched on earlier. As the word “holistic” implies, there a number of areas involved; I would encourage you to look at a document that was the result of a national group of different stakeholders who spent over two years developing a framework for enabling a holistic approach, which resulted in an ANSI standard (ANSI/MTS 1.0 WSIP Guide-2007, Whole Systems Integration Process). In addition to the standard, a book entitled The Integrative Design Guide to Green Building: Redefining the Practice of Sustainability (www.integrativedesign.net) was developed by some of the participants on this committee as well, and carries the discussion further.

Carbon Neutral cannot be achieved without the highest level of early and continued cooperation amongst the client, architect and engineers. The “good design is sustainable design” ethos promoted by quantitative analysis can make a great impact.  Architects get quick environmental feedback on design iterations and environmental engineers can input more into the design.  Achieving this kind of effective collaboration and cross-discipline understanding is, in my opinion, core to achieving truly sustainable, energy-efficient building design.

Stephen Choi, sustainable design coordinator at Broadway Malyan, one of our customers who are trialing some recent developments, noticed that: “On pilot projects when the architects knew that their designs were being tested in a tangible quantitative method, the way they thought about the design started to change. This and the analysis feedback was a learning catalyst for them. A greater understanding of the non-visual effect the lines they were drawing started to grow and over time, a better ballpark appreciation of what design elements mean in terms of energy use, solar and daylight performance developed.”

About the Author

Dr. Don McLean is the Founder and CEO of Integrated Environmental Solutions (IES).  He has 35 years experience in the use and development of building simulation analysis tools, including involvement in many landmark building simulation projects across the UK and Europe, such as Heathrow Terminal 5.  In 1994, he founded IES for the development of the Virtual Environment platform with the objective to overcome many of the commercial barriers to the uptake of energy efficient simulation practices within design firms.  Offering an integrated suite of performance analysis tools within one platform, IES continues to develop its tools, making them more and more accessible to architects and the mainstream building sector. Don holds a BSc in Environmental Engineering from the University of Strathclyde, and also spent nine years in the ABACUS unit at the Department of Architecture in the University of Strathclyde, undertaking a Ph.D. and Post-doctoral research.  During this time, ABACUS was one of the foremost departments in the application of computers in the building design process.

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