Sunday, November 29, 2009

Five Essential Roles for Performance Research

The Scandinavian hospital study illustrates a few unique contributions of building research, that energy modeling, commissioning, and system monitoring cannot offer:


1. Understanding of design intent.

The vision of the design team - owners, stakeholders, architects, and engineers - has a permanent impact on the energy performance of a building. Siting, geometry, orientation, envelope materials, organization of the program, spatial configuration, and environmental control system choices all reflect this vision, tempered by constraints of time, money, and building codes, and all have substantial impacts on the energy needed to heat, cool, light, and ventilate the building.


The effects of these key performance-affecting decisions are so decisive, and so long-lasting, that we must understand the forces that shape them in the design process. This element is therefore a cornerstone of building performance research.


2. Systems-level analysis.

Buildings operate as complex systems of people, machines, structures, and climates. Since these elements affect building performance as an interacting set, a clear understanding of building performance necessarily requires investigation into the operation of the system as a whole. Energy models do simulate buildings as systems, but their best role is to inform decisions among a limited set of design alternatives; they are definitely not diagnostic tools. To understand the operation, and especially the malfunction, of a real building requires field investigation.


Revealing unexpected activities of occupants, and understanding the origins of these activities, is an especially important aspect of field research. Unprogrammed use of spaces, manual overriding of system controls, and propping openings open or closed are just a few ways that occupants can unwittingly diminish the energy performance of their building; tracing these to their motivations, and then to concrete aspects of the building design or operation, is an essential component of systems-level building research.


3. Pattern discernment through comparison of multiple buildings of a type.

Each building is substantially unique: despite common elements, a particular assembly of spaces, materials, climate, program, and occupants is rarely duplicated. This complicates efforts to determine which performance strategies work well, and which don't, in a particular building type. Yet, as the Scandinavian hospital and High Performance School studies show, patterns do emerge when enough examples of a type are compared.


The seeking of patterns among multiple examples of complex systems has excellent precedents in field ecology (see work by E. Odum and J. Lovelock) and in architecture (C. Alexander, A Pattern Language). Their field techniques and analytical tools are directly applicable to building systems, as well, and should inspire us toward a "comparative building ecology" that illustrates performance patterns, in their contexts, robustly.


4. Controlled experimentation.

Although every building is an experiment of one, some experiments can be conducted within a building, nonetheless. Energy use of analogous spaces that differ only in occupancy or equipment can be compared; conditions in individual spaces can be tracked through varying seasons; passive airflow paths can be obstructed or cleared; light shelf sizes and angles can be varied; setpoints and schedules of mechanical systems can be adjusted, for example. While such adjustments are often undertaken by facilities managers, rarely are the results of individual changes tracked over time to yield meaningful information. Such experiments might also be simulated with models; an intriguing document by the New Buildings Institute presents such analysis for large buildings. Given the limitations of models, however, the realm of controlled experimentation remains an important one for teasing apart relationships among spaces, people, and environmental control systems in real buildings.


5. Publication.

The ultimate goal of pure research is to publicize the results, so that a wide audience can learn from them (where "publication" includes meetings, talks, discussion forums, and websites as well as design and science journals). In contrast, commissioning reports and building energy models are private documents; indeed, building designers and owners are understandably reluctant to publish evidence of performance below expectations.


At the same time, the disclosure of design decision pathways, model predictions, operational realities, and performance outcomes would help future design teams immensely. This, therefore, is the most important of the unique contributions that building performance research has to offer: the provision of reliable information, obtained through rigorous investigation and experimentation, unbiased by financial or legal interests, in straightforward, accessible forms with the strength to change common practice.

Sunday, November 1, 2009

What Does Performance "Research" Mean, Exactly?


If "research" means original research, and if buildings are created from principles of spatial design, climate responsiveness, structural stability, heat transfer, fluid mechanics, and hydrophobicity, among others, that are already known, then what, exactly, does "research" mean in the context of the built environment? What else is new, in these constructions, that we have yet to learn? More specifically, what can we learn that is generally true, and generally applicable - that can inform the design of future buildings?


To an architect, there is still quite a lot! To a social scientist, there is an equal abundance. But in terms of energy performance...what can original research really offer, that energy modeling or commissioning or just system monitoring cannot?


One study that's influencing our current work is still in progress by members of the University of Washington Integrated Design Lab in collaboration with BetterBricks and I-Sustain. Several additional people, including NBBJ architects and my boss, have also been closely involved. In this work, the group investigated a number of different Scandinavian hospitals, analyzed their geometry, orientation, layout, loads patterns, envelopes, hvac system design, and energy usage, and distilled a series of truths from the results that are evidently unknown to the US hospital design community. (One of their subjects was the Martini Hospital, above). This will be a fantastic resource when it's published!


One striking result, for example, was the superior effectiveness of decentralized ventilation systems in combination with radiant heating and cooling. While the inherent wastefulness of VAV reheat systems might seem obvious, with its strategy of cooling air to the lowest temperature needed by any of the zones served, and then reheating it locally for all the rest, the vast majority of American hospitals are designed with this exact system type. The next question, of course, is why? Are they cheaper? Easier to install? More reliable? Or just "the way it's always been done"? There must be some obstacle out there to changing common practice.


(to be continued...)