Summary: The 2009 Summer Research Scholarship, cosponsored by the AIA Committee on the Environment (COTE) and American Institute of Architecture Students (AIAS), went to Berkeley MArch candidate and graduate student instructor Nathan Brown, who focused on calculating the source energy performance of 28 COTE Top 10 projects and analyzing their performance against the baseline established by the Energy Star database of buildings with similar functions and weather conditions.

The intent of COTE advisors in directing this research was to establish a foundation for post-occupancy documentation of building performance overall and energy performance in particular for several COTE Top Ten projects. The final report is posted on the AIA COTE Web site.

Brown explains in his abstract:

Actual energy-use data were gathered for 28 projects for all fuel types. These energy use data are then compared to the energy use of a typical building of a similar type using Portfolio Manager, either by calculating an Energy Star rating or by comparing the energy use to a national average for a similar building type. The researcher develops a methodology to study buildings further as cases, including a set of interview questions to identify important points in the design and delivery of a building that may affect its actual energy use. From the list of buildings with Energy Star ratings, three were selected for the case study phase. The researcher then conducted a series of phone interviews, revealing crucial aspects of each design process.

Source energy versus site energy
One of the first elements of the study that Brown explains in his report concerns the 2030 Commitment to reduce carbon emissions and the foundation of the Energy Star methodology; specifically, the difference between site energy and source energy. Site energy use, which can be readily measured through changes in utility bills, is the energy consumed by a building. Site energy use, however, does not measure the energy expended to generate electricity and transmit and distribute it to the building. The key loss in this equation is in the conversion of the primary energy, such as the heat from burning fossil fuels, to electricity. As averaged for all fuel inputs for the U.S. in 2008, 63 percent of the primary energy is lost during the conversion of heat into electricity—for instance, the energy lost in turning the steam-powered turbines. Another 2 percent goes to ancillary operational aspects of the energy plant. Transmission and distribution of the electricity accounts for another 3 percent reduction from the primary energy generated. (For the case of this study, Brown ties carbon emissions directly to energy consumption and equates the 2030 Commitment of an immediate reduction of energy consumption by 50 percent to source energy, not site energy. By extension, he equates the 2030 goal of zero emissions to “net zero source energy.”)

The implications of this a priori energy loss factor are that calculating net zero source energy is not as straightforward as simply subtracting energy produced from energy consumed. Rather, one must inflate the energy purchased from a utility to account for these losses. Electricity sold to the grid and electricity purchased from the grid are not equivalent. As Brown notes: "A building may be considered a net zero source energy building if the renewable energy produced on site is greater than or equal to the source energy used by the building."

Taking this point a step further in his conclusions, Brown points out that further study would need to be done to account for embodied energy. For instance, the energy used by the manufacture of on-site renewable energy production, such as photovoltaics, could become an important factor when comparing the elimination of building systems with offsetting electricity use with renewables, he says.

Conclusions
The endless accounting complexities aside, Brown does develop six lessons learned. Taken straight from his report, his conclusion reads:

Low-energy performance as a design goal
The development of goals and the advocating for goals is a significant consideration that may, in some cases, trump the effectiveness of an integrated team. In the case of the International Fund for Animal Welfare, its above-average energy performance seems to have been motivated by responsible design principles and LEED™, with some benefit being generated by the integration of the contractor in the process of developing mock-ups. It seems that the exceptional performance of that building is in its preservation and restoration of wildlife habitat, reflecting the project’s top goals.

In the Terry Thomas, since the architect was planning on being a tenant and since a triple net lease was negotiated, there was motivation for the architect to design a highly efficient building. Thus, when a contractor was unfamiliar with the construction process for the sunshades, the persistence of the architect became important: it took multiple rounds of communication to reach an appropriate price for the shades. While the contractor was not closely integrated early on in this aspect of the design process, the persistence of the architect in achieving a goal proved decisive.

In the IRS Kansas City Service Center, the performance goals of the project were established very early in the design process through the negotiation of the lease. Whether these goals were as aggressive as they could have been seems to be an open question, but the establishment of specific performance goals that were tied to the targets of project cost eliminated the need for value engineering later in the design process as long as the design met the performance goals.

These projects not only underscore the importance of establishing goals for performance, they also show a variety of sources of motivation for energy performance.

Communication through mock-ups
Mock-ups were used in both the IFAW and IRS Kansas City Service Center. In each of these cases, there was some impact related to energy performance. At IFAW, electric lighting was reduced when a system of daylight reflection was verified. In order to reduce solar loads at IRS, a glazing modification was assembled as a mock-up to test its assembly and effect on the aesthetics of the design. Lastly, it seems that a mock-up might have been useful in both the Chartwell School and the Terry Thomas projects in order to facilitate communication between the architect and the contractor regarding the design of critical sustainable features. In Chartwell, a mock-up of the skylights would likely have resolved the issue of the added “curb” [which blocked light, negating the value of the light well] before it was constructed in the building. In the Terry Thomas, a more reasonable cost for the sunshades would likely have been achieved earlier had a mockup been done to allow the contractor to gain familiarity with the design.

Importance of the role of the designer
The Terry Thomas and the IRS Service Center show that the role of the designer is essential in integrated design. In the Terry Thomas, while team members were available from the start to provide a variety of feasible strategies and expert advice and analysis, it was the role of the designer to weave various interests and strategies together to form a coherent design proposal. This becomes a strategy in itself when the sustainable features become inseparable from the overall architectural proposal from the building; a courtyard is not likely to be lost in value engineering. In the IRS project, while a detailed energy model was completed by the contractor and used to assess and select low-energy strategies, the architect relied on experience and intuition in incorporating specific strategies in the final design.

Elimination of systems
There were multiple examples of design teams not simply reducing the size of systems, but designing to eliminate them altogether. In the Artists for Humanity EpiCenter project, in Chartwell School, and in the Terry Thomas, for instance, air conditioning was eliminated from the project entirely. A system that doesn’t exist will use zero operational energy and contains no embodied energy. It is no surprise then that Chartwell is the highest scoring building in the study. After a year of typical energy use data, the Terry Thomas will likely be a top performer as well. The challenge for design teams then becomes understanding the climate and life of the building in order to characterize and communicate the effects of eliminating air conditioning. If the daily and yearly behavior of the naturally ventilated building can be described, imagined, and accepted, this will go a long way towards reducing energy use in future projects.

Commissioning of systems and follow-through of the owner and/or facilities manager
In the examples where projects were subject to commissioning, it helped ensure that building systems were working efficiently. On the other hand, some projects suffered as a result of not having systems commissioned carefully. Likewise, it is important for the owner or manager of the building to remain invested in its energy performance over time. In the example of one house, energy use had steadily risen as systems were not maintained over time. When the systems were tuned and adjustments made, the house saw its energy use cut in half. This point underscores the limitation of actual energy use in assessing the sustainable qualities of a design, since the architect has no control over occupant priorities and behavior.

Metering and reporting of data
A study cannot evaluate what was not measured. Several Top Ten projects were not included in the dataset for this study because there were no data available. Reasons for this included no meter being installed, the meter was not maintained, or the owner was not willing to share data. If it is a future goal for the performance of green buildings to be studied more extensively, then it should become standard to monitor energy use in green buildings and for that information to be readily and publicly available.