The need for carbon-neutral design is based on the premise that our increasing realization of the seriousness of existing environmental problems and the significant role played by the built environment in this regard makes is necessary for architects to consider different methods of integrating various environmental performance issues in the form-making processes of architectural design. Such a need responds to and is motivated by the growing interest of the built environment professionals in achieving a more sustainable and environmentally conscious buildings and communities. While this integration can be achieved through various methods which differ according to the stage of the design process they are intended for, all of these methods aim to inform design decisions by an assessment of the expected performance of the community, building, or building component in question. This assessment should be based on measurable criteria such as energy consumption, lighting levels, solar shading and solar access, harmful emissions, or other impacts. Integrating sustainability considerations in the early stages of the design process is recognized to be particularly important because of the high impact that design decisions taken in these stages have over the subsequent environmental performance of the building or community especially when aiming for carbon-neutral designs.
While several definitions of carbon-neutrality can be found based on which phases of the building’s life cycle are considered, the definition considered for the seminar/studio model described in these documents is that Carbon-neutral or ‘zero-emissions’ buildings or communities can be defined as building or communities that emit no net carbon into the atmosphere through their operation. Achieving this goal requires the utilization of both passive design strategies as well as state-of-the-art energy efficient technologies to design buildings and communities that use much less energy than current practice (taking into consideration that up to 50%-80% reductions from average building energy use intensities are possible), and then to incorporate renewable energy generation systems into the fabric of the architecture to cover the remaining demand. This seminar adopts the position that achieving carbon-neutrality requires environmental performance issues to be considered in each phase of the design process and especially in its early stages, in which major design decisions are taken. While this was somewhat difficult to achieve in previous decades because of the time constraints of these early design stages and the lack of suitable tools that can be utilized in these phases to inform design decisions, recent generation of digital performance modeling and simulation tools offers designers the possibility of achieving such integration.
In the case of architectural education, an even more urgent need exists to introduce new generations of designers to the principle of integrating environmental performance issues in the design decision making process, and to train them to utilize the latest available tools that allows them to achieve this integration. Achieving this, however, requires a change from the traditional studio format in which projects are evaluated either solely or primarily on the bases of their form/image into one in which projects are evaluated comprehensively based on multiple criteria that include issues of environmental performance, such as carbon-neutrality and/or other concerns of environmental sustainability (e.g. resource conservation, reduced impact, embodied energy, etc.), as well as other relevant design objectives such as concept development, relationship with physical, cultural, and historical context, architectural forms and spaces, aesthetics, etc. Studios should also take advantage of the available performance simulation tools, many of which are specifically designed for architects/architectural students, and train students to effectively utilize these tools in informing their design decisions; and then to evaluate student’s project not based on their claims of performance but based on actual evidence that specific performance goals have been achieved. Finally, architectural students must be taught that the design of high-performance buildings does not preclude the designer from addressing any other relevant design consideration and does not, as is sometimes claimed, necessarily result in low-quality architecture.
Teaching carbon neutral design to students of architecture requires addressing a wide range of strategies, systems, and technologies typically associated with various aspects of sustainable design to achieve carbon-neutrality. As discussed earlier, this must include introducing students to state-of-the-art design decision support and environmental performance simulation tools, currently used by practitioners and researchers, as a means of informing sustainable and carbon-neutral designs. Students should also be provided with hands-on experiences in using these tools, which they can then utilize both in their current studios as well as in their future academic and professional design activities. These hands-on exercises should also be used to demonstrate how sustainable design practices can significantly reduce the negative environmental impact of the built environment, while providing more comfortable, healthy and economical buildings and communities. Courses teaching carbon-neutral design should also cover a wide range of topics, related to achieving carbon-neutral buildings and communities, including the definition(s) of sustainability, sustainable design, and carbon neutrality; climate analysis and climatic design strategies; building envelopes and indoor thermal environment; human thermal comfort; passive and active design strategies for different climatic regions; shading and solar access; passive and low-energy sustainable systems and technologies; daylighting; whole building energy use and building energy efficiency; ventilation and indoor and outdoor environmental quality; life-cycle analysis of sustainable building materials and systems; and sustainability assessment methods and frameworks.
Covering such a wide range of topics while in the same time training students to utilize the latest performance simulation tools in the studio is frequently made difficult by the time limitations of studios which do not allow students the necessary time to address these topics and acquire the skills needed to take full advantage of these tools. Based on this, the seminar/studio model presented in these documents represents an attempt to address this problem by introducing students to these important topics and tools in a separate seminar yet allowing them to directly apply the knowledge and skills they acquire in a studio setting through the use of collaborative teams between seminar and studio students. While several issues, mostly involving organizational and scheduling, have been identified during the course of this experiment that need to be addressed in the future, the experiment was relatively successful in general and resulted in effectively introducing a much larger number of students to the issues and tools needed to achieve carbon-neutral design than would have been possible using only the studio.
Studio Topics Key
Continuing the Conversation Follow Up Discussion between JW and HMR
JW- Given the ability of the seminar to introduce energy simulation into the studio setting, are you able to ultimately frame the assignments such that an individual project can claim in the final boards to credibly be zero-net energy? Does that goal have any real quantifiable meaning in the classroom, as opposed to in practice?
You seem to have many of the elements of this objective of Carbon Neutral Design listed (daylighting, solar control etc..)…. Can you describe a protocol that would put them together and lead to a credible claim of ZED by a student in your class/studio… or does the necessary objective remain to simply minimize loads and provide PV in the abstract, without a means of gauging how close to balancing those two things the design is?
It could be that at the schematic level of an architectural design studio, you simply can’t talk about a carbon neutral design as a concrete goal. How do we account for the energy efficiency attributed to the selection and design of the MEP systems, for example? Given these limitations, is it still possible to establish goals for each exercise that are appropriately aggressive? How do we know what those targets are? And do the exercises in any way build on each other to capture synergistic relationships? Put another way- does the goal of zero-net energy or CND offer a measurable new way to structure education about passive, environmentally responsive design, or is that too much to expect?
HMR- My thinking lies somewhere in between the two extremes you mention. On the one hand, the use of simulation tools clearly allows for exceeding the accepted objective of minimizing loads, through the use of passive design guidelines and rules of thumb, and providing PVs with no verification of achieving these objectives. On the other hand, however, it is difficult for studio projects to credibly claim/achieve zero energy and/or carbon neutrality both because of the limitations of the schematic design stage (lack of time, details, etc.) and the fact that we cannot account for the potential savings of advanced mechanical and electrical systems (both of which you mention), or any potential integrative solutions to optimize the performance of both envelop loads and systems. While the simulation tools we have available now do allow for accounting for such savings, this requires a level of experience beyond that of most architecture students, and many of the faculty, and therefore it is only possible to use the tool defaults, which represent average, code-complaint, system performance.
However, measurable performance improvements for whole building energy use can be set and verified. This can be achieved by comparing the results of the whole building energy use simulation (in terms of EUI measured in kWh/ft2 for example) to average US building energy use for buildings of similar location, type, and size (obtained from available tools such as EPA’s Target Finder). As the simulation will be based on average mechanical and electrical systems performance, performance improvement targets should be limited to possible improvements resulting from building form, orientation, envelop improvement etc. (in the range of 20 – 30% from average usage, which is still a significant improvement). There is perhaps a need for research projects that try to quantify potential location and building type specific performance improvement targets due only to architectural design improvements.
A more accurate way of verifying performance improvement, which I did not include in this offering of the course but plan to use in the future, would be so simulate a baseline building energy usage, again using code-complaint system characteristics, and compare the energy usage of the students’ designs to that of the baseline building similar to the process used to verify code-compliance and LEED® certification.
Similarly, aggressive performance targets can, and should, be set for each of the element systems (shading, daylighting, etc.). These goals can be derived from existing or proposed building performance standards and initiatives (ASHRAE 189, 2030 Challenge, LEED®, etc.). For example, achieving the LEED® target with regard to space daylighting. Yet again, these targets will probably fall short being of zero-energy for the same reasons discussed above.
The design of the assignments in the seminar did aim to capture synergetic relationships between the different systems in the building and to gradually build up from the individual components to the overall building performance. For example: relations between site resources, building form and orientation, and occupant comfort; shading and daylighting; daylighting, HVAC, and artificial lighting; etc. These relationships were discussed extensively in class.
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The seminar utilized several performance analysis and simulation software, each aiming at performing a specific analysis task. However, much of the design analysis tasks were performed using ECOTECT. The software used included:
1.The Weather Tool:
This tool was used to conduct a climate analysis of the different selected project locations. While CoA did not purchase a site license for the software, student took advantage of the available Demo version.
This tool was very easy to use and proved very useful for student to conduct detailed climate analysis. In addition to its capability to provide a graphical analysis of the main climate parameters (temperature, humidity, etc.), the tool also included the capability of assessing the impact of one or a combination of passive design strategies on the thermal comfort of the building’s occupants. This feature proved very useful for student to explore combinations of passive strategies at different times of the year and to identify the optimum mix of strategies for their location.
2.ECOTECT:
The seminar heavily used ECOTECT in several of the performance simulation and analysis tasks performed including basic modeling, solar access, solar control, daylighting, and thermal load analysis. In addition, ECOTECT models were used as a basis for daylighting simulation using RADINACE. ECOTECT proved to be a very useful, effective, and flexible tool that allows student to graphically analysis several performance aspects of their designs and to easily modify their designs and assess the impact of these modifications of performance.
On the other hand, while some students had no difficulty in learning ECOTECT, applying it to their projects, and taking advantage of its multiple analysis tools, others experienced some difficulty in acquiring the necessary skills and required additional support from the instructor and their colleagues. In general however, all students had a favorable view of the tool after the seminar and many indicated they will utilize it in their future studios. In the case of ECOTECT, a site license was purchased and the majority of the students also purchased student copies from the software.
3.RADIANCE
This tool was only utilized through exporting form ECOTECT with the aim of providing students with a method of producing accurate rendering of daylighting conditions in their projects. Most students had no difficulty performing the rendering, however, it has to be noted that exporting form ECOTECT limits the possibility of taking advantage of the capabilities of RADIANCE. Students were also hampered by the lack of windows-compatible material files.
4.eQUEST
This tool was used to conduct a whole building energy use simulation of student’s final design project (after several optimizations using ECOTECT). This was needed because ECOTECT simulates only heating and cooling loads and does not simulate whole building energy use. Results from eQUEST were used as the basis for sizing a PV system and subsequently calculating the projected carbon footprint of the project. Students were limited to using eQUEST’s design development wizard which reduced the number of needed inputs, thus making it possible for students to conduct a relatively quick and reasonably accurate simulation. However, the DD wizard is based on several built-in assumptions that may well affect the accuracy of the results.
5.EPA’s Target Finder
This online calculator was used to identify the site & source energy use intensity for the project as well as its projected CO2 emissions. The tool was also used to compare the energy use intensity of the project with conventional buildings of similar type and location as well as with high performance buildings (top 10%) as defined in the target finder tool. The tool was relatively easy to use and offered students a realistic benchmark to compare the performance of their projects to.
6.Athena/BEES
Both of these tools were presented as possible means of conducting a life cycle assessment analysis of building materials/systems. The tools were not addressed in detail because of time limitations and because the project focused mainly on the carbon foot print of the building during operation and not the embodied energy of materials.
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