Sefaira green building analysis
Published 14 November 2012
|Written by Martyn Day|
AEC magazine looks at a new web-based green building analysis tool that targets architects at the conceptual stage.
If you do not know how a building will perform, how do you know it is the best design? Costs will be exponentially higher if a design reaches the engineers only to require additional mechanical components for cooling, or changes made to natural ventilation systems. Architecture is just as much engineering as it is art and architects need to avoid making early mistakes.
So-called ‘Green Building’ applications are looking to fill this space. However, I feel the ‘green’ badge in this case seriously undersells the capabilities of much of the software and may turn off designers to the real value of these tools, which are able to improve the performance of the overall building design, not just its ‘green’ aspects.
The problem with most building design tests is the time it takes. A single detailed design test can take anywhere from one hour to several days for a qualified engineer to complete. This is because building design can be incredibly complex. There are many variables that can impact the end performance and ongoing cost of maintenance: materials, orientation, glazing, airflow, energy usage, statutory compliance, usage, shading, weather and solar gain.
Launched in 2009 and winner of last year’s Ecobuild ‘Green Building Innovation of the Year award’, Sefaira started its life as the MBA research project of Mads Jensen (CEO) and Peter Krebs (CTO). Now based in London and New York the firm is building a suite of cloud-based building analysis tools.
The company’s first product is called Sefaira Concept and is aimed at the conceptual and massing stage of the design process. Unlike most analysis tools, the ‘engine’ is located in the cloud. The advantage being that massive processing power can be used for very quick results for both single and parallel runs. This makes Sefaira a SaaS (Software as a Service), accessible through a standard web browser.
As a service, users do not own the software but subscribe to annual usage for £1,200 a seat, which includes training, support and updates. Larger firms pay £3,250 for a bundle of three seats with enhanced training, enhanced support and access to engineers. For £100 a month or less, Sefaira provides a lot of bang for your buck.
Sefaira has been designed to work with SketchUp as its base modelling source. While this free tool lowers the cost of entry and is ubiquitous in the market, most Building Information Modelling (BIM) managers I know are trying to stamp out its use as it breaks the BIM workflow, with architects lobbing in unco-ordinated changes via SketchUp model. That aside, SketchUp can import models from all sorts of professional design tools so this is perhaps less of a deal breaker on the analysis side.
Sefaira has recently launched a plug in for SketchUp, which graphically shows how the Sefaira analysis engine has broken down the model. Labelled textures (wall, glass, etc) means users can assess if the correct allocation has been applied. It is also possible to reallocate entities to help the software define the make-up of a proposed design.
However, it remains essential that all items are correctly identified before analysis, as it is ‘rubbish in, rubbish out’. The models do not have to be particularly detailed, for example it is possible to define floors based on the envelope in the system.
Start a Sefaira session by logging in to a browser. On log in, you are presented with a list of the projects you are currently working on and these can be shared with other project participants anywhere in the world. Collaboration on Sefaira is really a useful byproduct of using the cloud.
To start a conceptual or retrofit project the system needs a SketchUp model and a location. Using Google maps and a built-in sketch tool, a site can be easily drawn and brought in from SketchUp (should it have been created there or imported through it) to place the proposed building in its correct orientation. Surrounding buildings can also be quickly block modelled for over-shading analysis. Now the system automatically works out areas, volumes and gets the nearest weather data and even has the ability to run analysis with predicted climate change weather models.
It is possible to initially work with the default wall and glazing settings but all these can be edited by the user. All the spaces need to be allocated uses, which includes residential, office and capacity, together with lighting and load densities. The system can differentiate between week day and weekend loadings, supports zoning, cooling points and is highly configurable.
With a model, a site, weather and usage Sefaira is ready to run some numbers. The software performs an analysis for every hour of the year (by my calculations that is 8,760 hours). The company aims to return a completed set of results within 10 seconds, including a host of statistics such as the annual energy consumption, annual cost, annual CO2, heating and cooling loads as well as many other metrics. All are clearly graphed and indicate the essential performance criteria. According to Sefaira these results, even quickly delivered, are within 5%-10% of competing systems at the conceptual design phase.
Now the fun starts. ‘Tick-box strategies’ can be applied to improve the performance by looking at materials, structure, orientation, U-values, brise soleil, Photos (PV), and solar shading and natural ventilation to name but a few. It is possible to create a number of parallel strategies for one design and compare the results. So, what if the roof was covered in PVs, or the design had higher U-values? These strategies could be analysed in parallel and compared side by side, showing performance results together with cost implications of build vs operation. Seeing the price impact could change a client’s mind for a better performing design.
It is also possible to combine a number of these strategies together to create ‘bundles’, which could be the basis of a new design or one of a number of designs that need to be compared and analysed. This is incredibly powerful and a great example of how the cloud will change the way we work — away from where any change in the design could lead to delays, to early on-demand analysis.
The system has the unique capability of producing response curves on a number of criteria that will help the user select the optimal setting vs cost. The response curves give a visual indicator of which factors will have the biggest impact on improving the design for the least cost, such as shading, glazing ratios and orientation.
Sefaira results can be used in the preparation of documents for LEED, Breeam, and Part L certification and has a built-in report and graph generator, ideal for presentations and design meetings. It is working on additional modules for financial planning, daylighting analysis, materials and others
While commendable, the ‘Green Building’ label has a distinct disconnect with what the majority of design jobs involve. LEED and Breeam are not applied to run of the mill projects and many clients will go for the cheapest building over the ‘green’ one.
However, these tools do have a place on every project because the industry has to better understand building performance. I would suggest that these ‘green’ tools are essential Performance Analysis tools and akin to Finite Element Analysis (FEA) and Computational Fluid Dymanics (CFD) tools that are used in engineering firms, especially high performance engineering such as Forumla 1 or aerospace, which simulate their prototypes before fabrication.
For a first generation application, Sefaira is incredibly impressive. The interface and ease of use is very straightforward and working with SketchUp as a base modeller significantly lowers the cost and broadens the appeal of the service. With near instant results, it is possible to sit in front of a client and compare multiple design configurations and see the construction and operation cost implications. Or simply use the reports it generates to back up your final design submission.
Sefaira equips architects with a powerful range of tools and capabilities to understand a design with fewer changes as it goes through the engineering and documentation phases. Good building professionals analyse early and often.
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