Interview with AECOM: Discover the mind-set behind the winning entry of the Building Simulation 2017 Open Practitioner Competition

By Liam Buckley on Wednesday 25 October 2017

As part of the Building Simulation 2017 Conference in San Francisco in August, the local IBPSA-San Francisco Bay Area Chapter organized an open practitioner competition, whereby the winner of the competition would be announced at the conference.

There were originally 40+ applications entries to the practitioner competition, with 12 Teams from five different countries making a final submission. The sizes of the practitioner teams was to be determined by the individual team itself.

There could only be one winner who would take home the honours, and with it, a $1,500 Cash Prize sponsored by IES Ltd.  That winning team was “AECOM’s High Performance Buildings and Communities Team“ – so a big congratulations to that team.  This short interview will attempt to gain insight to the mind-set of the highest level of building performance in the practitioner world today. Representing AECOM’s High Performance Buildings & Communities, is Victoria Watson, an Associate with AECOM and team captain of the winning entry.

THE COMPETITION BRIEF:

The practitioner modeling competition was for the “Design and Simulation of a Laboratory Building” in San Francisco, which included requirements for minimising building energy consumption by designing the most efficient MEP and envelope systems possible, while maintaining comfortable conditions inside the building. Innovative simulation-aided design was encouraged.

The report for AECOM’s winning entry can be found online.

IES:
This might come as a bit of a surprise to you, but the number of participants from the varying competition entries ranged from one single person to nine people on a team, and AECOM had the team of nine on it.  Please tell us about the teamwork ethos at AECOM and why you chose to include that many team members as part of your entry?

AECOM:
Wow, that’s interesting.  I think the competition brief was written in a way that appealed to individuals and groups in different ways which is great.   We wanted to use the opportunity to include the whole team at the time so we could capitalize on the team building experience.  The whole team doesn’t get to work on the same project in our day to day project activity so this was a great opportunity.   Having a large team also allowed us to cover lots of different expertise from modelling HVAC systems to creating visually appealing graphics. Everyone on the team had different strengths and together we are stronger.

IES:
Funnily enough, there was a team entry of one person who came in third in the competition and a team of only two people who came in second. Surely, you must have had some headaches during the design, or is that all part of the process?

AECOM:
Having a large team definitely required more coordination between everyone to make sure we fully capitalized on the benefits of team work.  Working within AECOM as a large multi-discipline design consultancy we were all used to working on large inter-disciplinary teams.   However, the fresh twist was operating as a multidisciplinary team…within an existing team.  This gave us a new perspective on things as we found it much easier to break down some of the communication barriers you can sometimes find on projects as we were all aligned in the project goal.

IES:
The design brief called for accurate and intelligent use of building simulation in your design process. Your winning report demonstrated a rather unique visualisation describing your various simulation analyses during the building design process, at different phases of design. Can you describe this to us?

AECOM:
Our design process focused on the importance of integrative design between the different expertise in the team (MEP/Architecture/simulation) to ensure a high performance solution can be achieved.

“From the beginning the entire team was committed to ensure a continuous integrated approach was implemented to produce a final design solution,” said Abhinay Sharma who created the Integrated Design Process graphic.    “The team pursued a non-linear approach throughout the allotted time of 8 weeks and converged at final solution unanimously. This approach naturally pushed the process graphic from a linear timeline to a spiral culminating in a design solution at the end. This provided the opportunity to showcase when each of the processes started and how they interacted with other ongoing processes. The spiral shape also allowed us to incorporate the 8 week timeline in a circular fashion thus providing a concise snapshot of time used in every process.” 



IES:
On that note, do you have advice for what tools should be applied at different stages of design, or is that something that evolves differently for every project?

AECOM:
We find that energy simulation tools are constantly evolving their capabilities and therefore we try to keep abreast with these changes so we can utilize these.    We do find that different tools are more appropriate at different stages of the design and it’s not possible to use a “one size fits all” approach.   We do consider each project when deciding how much energy simulation should be undertaken, when should it be undertaken and what tool should be used.  Factors that influence those decisions include project performance aspirations, timeline, budget, code requirements, client requirements and the design team.   We tend to split our performance based design tools into conceptual (E.g.  Sefaira / Grasshopper) and detailed (E.g. IES / Transys).  We look for opportunities’ to bridge the gap between the tools where possible and that’s where interoperability is very important.   One of the most important things is that the person controlling the tool is comfortable with that tool (to avoid garbage in = garbage out) and sometimes this will mean a certain tool is actually the right choice for a particular project because of modeller expertise.

IES:
Can you describe what “multi-objective, multi-variable optimization simulation” is and when it should be applied on a typical project?

AECOM:
Multi-objective, multi-variable optimization simulation is when you are trying to optimize multiple outputs (in our case minimize glare and maximize daylight) whilst varying multiple variables (in our case number of windows, window area, location and shading) within the limits set.

“This evolutionary trade-off analysis tool is the best way to provide energy performance feedback for design decision support in a quicker and comparatively more accurate way,” said Xiaofei Shen.  “This is especially important at the beginning of the conceptual stage when there are millions of redundant iterations generated from the parametric models, which is more possible due to the extensive usage of scripting architectural design programs nowadays. With the limit of time and budget restrictions, we’ll rely more and more on this rich-data multi-task methodology to tackle the complex active system design issues in future performance based building design.”

The computational capacity that we have at our disposal today through our regular computers is enough to solve thousands upon thousands of possible outcomes for a given set of inputs,” said Aman Singhvi who led the multivariable optimization process.  “Multivariable multi-objective optimization process numerically eliminates ‘unfit’ design solutions through an exhaustive search-and-optimization process. Even though this method can be used at any stage and at any scale of the design process, it is immensely useful in the early concept stage when there are countless parameters affecting the design, resulting in virtually infinite solutions.”

IES:
How important is it to identify the synergies between various energy end uses, when analysing passive and active design strategies?  What approaches did you consider for this during the competition?

AECOM:
It is important as building design involves a lot of trade off of different elements therefore considering synergies between strategies allows the “biggest bang for your buck” approach to be taken.   It is also important because sometimes energy performance can throw you results you weren’t expecting that can be missed when looking at things in isolation.   A good example of this is with earth tubes or heat recovery, where it’s easy to see how these techniques can reduce building heating and cooling load, but they also increase fan energy.  I learnt this the hard way moving from the UK where heat recovery was seen as a “no brainer” to sunny southern California where it often doesn’t stack up.

“The primary idea was to first identify all the lowest hanging fruits given the design brief/ constraints,” explained Sandy Mukherjee who led this process for the competition. “Listing out our active and passive design options side by side allowed us to understand where all the synergies lied and which ones we could take advantage of in our design. We took smaller parts of the building to first test out our various strategies as well as to ensure that the synergies are working in our favour and as we expected. We then applied it to the whole building. This part-to-whole approach rendered some confidence in our modelling, especially for systems that aren’t very straightforward to model like the earth tubes.”



IES:
There were some very innovative design features integrated into the design, such as solar tubes, wind-catchers, natural ventilation via operable windows, solar shading, high-efficiency VRF and below-ground ventilated earth tubes. In hindsight, how difficult was it to accurately simulate the performance of each of these design features?

AECOM:
We definitely had some challenges trying to ensure we were modelling certain elements as accurately as possible.  However the reality of energy simulation is that there is also some trade-off on accuracy when bringing certain strategies together into an energy model.  One software can’t be an expert in modelling the intrinsic detail of every design solution, however for us finding a reasonable level of accuracy that we could comfortably trade off approaches against each other, was what we were looking for.

IES:
The HVAC modeling diagram seems quite involved and we recognise ApacheHVAC being utilised. Do you have any advice for integrating the process of HVAC sizing and HVAC energy simulation with this tool?

AECOM:
ApacheHVAC is great for modelling bespoke systems as it allows for ground up construction of the system air streams and controls and so can be tailored to suit most situations. Using the in-built prototype systems is a great way to get something up and running quickly and also use for reference when building new systems.  It’s important when using ApacheHVAC though to take ownership of the controls and components and work through them understanding what is being done at each step (and making changes where it doesn’t match the design).   There is definitely some trial and error involved with running it through ApacheHVAC but that’s part of the fun of learning!  Sometimes the control strategy will be left until the end of design but using ApacheHVAC brings it to the front of design where it should be as you need to be able to set up and control the systems in the model (again the prototype controls are a great starting point).   ApacheHVAC is always improving in auto-sizing capabilities and this can be very useful at a stage where the system design has not fully evolved.   


IES:
AECOM’s use of visual analysis in the design brief was exceptional. Is this due to a limitation in existing simulation tools or rather an intentional method to apply your own unique visual techniques in order to standout?

AECOM:
Being able to present design ideas and analysis in a visual fashion is important as many people find it easier to understand things when presented in this way.  Having the larger team enabled us to pair up expertise – detailed analysis with graphical expertise to ensure we had robust analysis behind the visuals.   What makes visualizations so powerful is that they put the key information up front and therefore ensure the take-away message is what you are trying to communicate.   This inherently means that they are often bespoke as one solution doesn’t fit all and therefore unique visuals are much more powerful.

IES:
On that same topic, what is your advice for the commercial building performance software vendors for visualisation outputs? Do firms like yours prefer ‘canned’ reports and graphs, or do you prefer a facility to export data, and customize the output, or are both options still as desirable as ever.

AECOM:
I think that software vendors should focus on making sure they can provide outputs clearly which can be worked with in a user friendly manner (E.g. viewing different parameters / saving selections) so the tool can be used for analysis and exporting the data.   If this can be done well it supports the actual analysis being done quickly in the tool which frees up time for any bespoke visuals if needed outside the software that work for the project.

The data from the building performance simulation software is objective, which is required to be accurate and consistent with each other no matter what software you use” said Xiaofei Shen who led the team’s graphics production. “The way we visualize the data, on the contrary, needs to be customized, which is more subjective, to fit into different situations from one project to another. In that case, we prefer all the parameters and outputs exported from the software to be editable in different formats, so we can always have our own options to address them in different ways. Sometimes integrated with the architecture and building system design, for better and easier communications with designers, clients and the public.”

IES:
The reviewers noted that while AECOM targeted low energy consumption in your report, metrics for thermal comfort and daylight performance were simultaneously analysed. How important is it to provide an integrated whole-building set of solutions?

AECOM:
This is very important. The concept of a high performance building is not limited to energy performance but also includes occupant wellness.  The building is built in a matter of years (sometimes less..) and is in use for decades typically being built for occupants.

IES:
After all is said and done, was the experience of the competition worth it for the recognition and/or for the internal team-building? Will you take any lessons learned and apply them in your day-to-day practice?

AECOM:
I definitely think it was worth it for the improved skills, the community recognition of our efforts and most importantly the team-building element.  Let’s see what some of the team thought!

“We have explored various capabilities and skills among our team members, which not only expanded our understanding of what we each can work on, but it also enriched our modeling knowledge; and strengthened further our foundation for future collaborative works” said team member Maria Spastri.

“The experience of going through the process definitely taught us 2 things,” said team member Sandy Mukherjee.

“1) Effective and timely collaboration and team work is instrumental in producing quality deliverables. With a diverse team, the workload gets distributed and members can take ownership of various parts of the design which can then at the end get stitched together.

2) Often at times, as we’re more technically inclined, we focus more on the energy simulation results/savings side of things but tend to ignore the story telling piece. Strong visuals backed by robust analysis can sometimes be very effective in portraying the strong side of the design, whereas analysis outputs by themselves can get one lost in numbers.”

AECOM’s team included Victoria Watson, Sandy Mukherjee, Abhinay Sharma, Maria Spastri, Aman Singhvi, Xiaofei Shen, Kenneth Teeter-Moore, Calum Thompson and Lisha Deng.

FINAL NOTE FROM IBPSA-SFBA AND IES:

Thank you again to AECOM for raising the bar with this simulation report. I really hope the organisers of the next Building Simulation Conference in Rome include a practitioner competition.

This interview was also published in the October 2017 IBPSA News Volume 27 No 2

Liam Buckley

Liam is the Vice-President of IES West Coast Division of North America and manages the software, training and consulting for IES in that region. He is a Chartered Engineer and is an ASHRAE certified Building Energy Modeling Professional (BEMP).