The clever title—Aggressively Passive: Employing Passive Systems for Load Reduction—established a focus for AIA+2030 Session V. The evening’s speakers succeeded in presenting information on the topic from a number of angles. The end result was a well-rounded curriculum providing an approach to passive system design. Here is a review of those talks.
First up was Khee Poh Lam, PhD, RIBA who began the evening with a rousing discussion of bioclimatic design, building performance mandates, and building simulation. Dr. Lam purports that energy efficiency is a proactive task that begins with an understanding of the site’s relative conditions. To demonstrate, he presented several examples of indigenous structures in extreme locations around the globe. The key to passive design is to control conduction, convection, and radiation in the building. Step one is to set up a weather station on site. This, says Lam, is the only way to understand the site’s specific climate conditions. In climates like Pittsburgh, with four distinct seasons, this means monitoring the site for an entire year. This prolonged monitoring might seem difficult to fit into the average design phase length. However, if the idea is presented to the client early, like in the negotiation phase, recording a year’s worth of weather information is achievable and invaluable.
Energy simulation is a critical tool for successful passive design. Lam discussed the ways in which this tool has been useful in his projects to evaluate pertinent characteristics. Energy simulation facilitates the necessary examination of outside and inside air flow simultaneously. The passive design cannot adversely affect the surrounding built and natural environment (i.e. creating wind tunnels, shading adjacent buildings). The design also needs to be checked against all other performance mandates for the project (i.e. spatial, visual, thermal, acoustical, building integrity). Energy simulation is the vital diagnostic process for measuring building performance, evaluating impacts, and establishing benchmarks.
The second presentation of the night picked up right where Dr. Lam left off. Mark Dietrick, AIA, LEED AP, of Case Technologies provided a demonstration of several computer-based appraisal tools to perform the energy simulation. Dietrick pointed out that oftentimes energy modeling is not started until after key decisions have been made. Those choices, when made before the scientific analysis can be applied (i.e. siting, massing, and building orientation), can significantly affect the building’s performance potential. Several software tools designed for the architecture community provide a method for applying science in those early decision phases. We are no longer in the information age, proclaims Dietrick; we are now in the big data age. The trick is taking all the data and structuring it in a way that can inform our design.
The latest tool from Autodesk—Vasari—fills in a gap in energy analysis not addressed well by their other BIM products. Vasari is a conceptual design tool in which you can quickly develop your building massing and the massing for the surrounding context, then run a series of climate condition studies (i.e. solar radiation, shading, wind) and modify your design as necessary. From there, you can upload the model to Green Building Studio and Revit for the next levels of development. Vasari’s energy analysis is not the definitive solution, but it does provide the type of relative information that is so helpful in those early design stages critical to energy efficient design. It should be noted that other companies are developing comparable conceptual simulation tools. For instance, Sketchup has a plug-in that does many of the same analyses as Vasari.
The evening ended with a valuable introduction to the Passive House Institute US (PHIUS+) presented by architects Laura Nettleton, AIA and Michael Whartnaby from Thoughtful Balance. The Passive House program has been a high-performance design tool in Europe for several years, but it is relatively new to the United States. There are over 40,000 Passive House-certified buildings in Europe. There are only around 40 in the US.
The Passive House certification is a much more iterative process than the common green rating systems, with several stages of inspection and testing during construction. Since the rating system is based on performance goals, it pushes the designers to get creative with their solutions. The PHIUS+ criteria focus on goals for envelope, solar orientation, ventilation, and efficiency, with renewable energy as an optional pursuit.
Nettleton and Whartnaby discussed several of their Passive House projects to demonstrate strategies that have led to successful PHUIS+ certifications. The primary goal is to reduce the energy use as low as possible. When that is done properly, utilizing renewable energy to cover the remaining need becomes a feasible route to net zero energy. The key to achieving the Passive House goals while preventing escalating project costs is to transfer money into the building envelope. With an airtight and super-insulated thermal envelope, high-quality windows, and attention to thermal separation and skin penetrations, less money needs to be spent on mechanical systems.
Surpassing the halfway mark in the series, Session VI will occur on November 14th. This session, titled Illuminating Savings: Daylighting and Integrated Lighting Strategies, will offer strategies and tools for maximizing daylighting and minimizing heat gain and glare leading to a reduction in energy consumption. Session speakers will include Astorino’s Director of Digital Practice, Brian Skripac, Assoc. AIA, and Sustainable Design Manager, Rudolph Marnich; Paul Petrelli, PE, CPMP, LEED AP BD+C, principal at HF Lenz; and the team of Joe McGrath of Wattstopper and John Northern of Repco II. Attendees will benefit from this roster’s experience and enthusiasm for the topic.