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Mount Angel ID Roundtabl-Part I
The following article is the first part of a three part series drawn from a roundtable discussion that occurred in August 2007 about integrated design, among principal project team members responsible for design of the Annunciation New Center for Theological Studies graduate theology building at Mount Angel Abbey. The cross-disciplinary collaboration among project team members was a hallmark of this project, but specific areas of responsibility are indicated for each of the panel participants.
For details about the project, please see an overview brochure on the Annunciation New Center for Theological Studies developed by SRG Partnerships, Inc.
Father Michael Mee served as the Chair of the Building Committee and became involved several years before the actual design process started, as the Monastic Community and Building Committee composed their ideas about project aspirations. He also participated through the construction phase and occupancy, and knows all phases of the project well.
Kent Duffy, FAIA is a Principal of SRG Partnership, Inc., the project architect, and served as Principal in Charge and Project Designer.
Michael Hatten, P.E. is a Principal of SOLARC Architecture and Engineering and was the mechanical engineer and energy engineer for the project.
G.Z. "Charlie" Brown, FAIA, is a Professor of Architecture at the University of Oregon and Director of the Energy Studies in Building Laboratory (ESBL). Under his leadership the ESBL designed, built, and monitored the performance of a full-size classroom prototype, in order to facilitate project team investigation and evaluation of daylighting, night ventilation of building mass, integration of mechanical and electrical systems, and to inform and define the passive systems approach that was incorporated into the project.
Kent Duffy ("KD"): We had a great conversation a week or so ago, among the four of us about topics to cover during this panel discussion. What came rushing back was what a great time we had doing this project. Everybody up here ended up doing something they'd never done before and counting on the other people at the table to make those innovations work, and although we're always trying to do something more than we've done before we trusted each other to do it together and we just had to keep working at it until we made it work.
Our office has worked with G.Z."Charlie" Brown on at least a dozen buildings and with Mike Hatten on LEED on at least a half a dozen buildings and we see this highly energy efficient integrated design approach getting implemented more and more. However, as much as you hear about LEED buildings, there are still not that many buildings that have done it yet. We're still learning a lot about what works best.
Father Michael ("FM"): From the Abbey's point of view, we began looking at the needs of the hilltop and a master plan long before this project. Many people helped us articulate what we were trying to do in putting a new building on this hilltop. I remember many conversations Kent and I had about our Alto Library and other buildings. One of the wonders I find in this building, even before we get to the energy efficiency, is the beautiful melding between the architectural styles of the hilltop and the library and the unity that's brought about by this building.
KD: There is a tendency on a client's part to think that if a building is passively heated, cooled and lit, it requires less engineering than what we'd call an active system building. In reality, it takes much more engineering and much more sophisticated engineering, because you don't have the benefit of powerful fans and chillers and cooling towers to make things work and achieve the comfort that people expect. You have to find ways of getting the air to move through the building and heat the mass of the building, in really remarkable ways, with the least amount of energy, which is, in my mind, a real test of engineering. Getting the air to flow through a building--it is exactly like water flowing downhill. Air will take the path of least resistance and if you put something in its way, it will go someplace else. You really have to think about creating that path of least resistance all the way through the entire building to get the air to move through.
The classrooms and boardroom are all one-story and have natural ventilation coming through the exterior walls of the building, venting up to the roof. They also have daylight apertures that bring light into the room. Another of the building portions is three stories high. When you enter the building, you're at the middle level of the office portion, with one level below and one above. And so one of the puzzles we had to solve was how to get the daylight into those spaces and ventilation air moving through the whole building to ventilate and passively cool those areas, too.
G.Z. "Charlie" Brown ("CB"): Many of the high performance features of this project had their origin in a high performance classroom prototype project that we did with BOORA Architects, and Mike Hatten was the mechanical engineer on that. Our goal there was to demonstrate that we could get high levels of performance at low cost. And in order to understand how classrooms use energy, we took a look at energy use in schools. For the heating load, one of the things that you can see is how outside air becomes a dominant force in energy use. It's because all of us breathe all the time and code requires that we introduce outside air. On the cooling side the same thing is true. Infiltration is a fairly important factor, lights are fairly important. It's interesting that people are also contributing quite a bit of heat to the building, which turns out to be a cooling load here, but you'll see later how we use it effectively to heat the building.
This is a little diagram that we've developed for BetterBricks to try to explain how things can work together. We begin by analyzing context, in our case, climate. Climate is often seen as a liability, but in our case, we see it as a resource. And you'll see how this building takes advantage of that.
During the programming stage, identify use patterns. The fact that this building is not used all year long is a significant factor influencing the design. In addition to the typical architectural goals, we also wanted to create small loads in the building-small need for heating, small need for lighting, and small need for cooling. Then we want to have systems that are sized to match the small loads. What we're doing is looking for synergies between those elements so that we can get one element to do multiple things, therefore increasing performance while reducing cost.
In the classroom prototype project we started trying to figure out, first of all in the use category, the criteria for lighting and for comfort. We did a fairly extensive look around Western Europe and Asia and the United States and found a lot of variation. Classroom lighting in Denmark is on the order of 20 foot-candles, while the Illuminating Engineering Society (IES) standards are quite a bit higher. In the high performance classroom prototype, we were looking for something that is in the 20 to 40 foot-candle range. That criterion for lighting is much lower than what IES would have you think was necessary.
Thermal comfort is the same. ASHRAE now defines the hot end of the comfort zone as 80 degrees, if you have low relative humidity. We're fortunate here that often when we have high temperatures we also have low relative humidity. If you have air movement, you can easily increase the comfort zone by 3 or 4 degrees.
Michael Hatten ("MH"): I want to add to the discussion of loads. One place where the high performance classroom prototype and this project is a bit different is presence of the inlets and outlets in this naturally ventilated design. And that is not an insignificant thermal characteristic of the envelope. We used computational fluid dynamics (CFD) optimization, to size the inlets and outlets. We did not want to oversize them to keep conductive heat loss to a minimum.
Direct solar gain is another interesting load. The central design feature, a humungous skylight in the middle of this classroom, has a cooling load impact and, in fact, a heating load impact. So, this is another reason why we want to provide just as much light as we need and nothing more. We began with considering some of our options with louvers and even potentially insulated louvers, to control solar gain, and possibly provide a thermal benefit. This was one of our significant conversations around the high performance classroom prototype.
Obviously, we're designing classrooms and we're going to have a lot of people in these classrooms who will give off heat. Although, we can potentially use that heat, it still remains one of the major cooling loads.
Charlie mentioned ventilation on the heating side, it's also true on the cooling side-outside air ventilation is the significant load issue, with implications for how we might address these loads with systems concepts. One general principle is that you may want to seriously consider dealing with ventilation in a separate dedicated and special way, not necessarily as part of a set of mixed air dampers and some air handlers on the roof. That principle has been expressed in this design-each classroom has its own dedicated heat recovery ventilator. And then for the more complex and integrated spaces-the offices, the corridors-there is a building level heat recovery ventilator on the roof that provides ventilation air.
As we began to get some operating experience with this building-it happened to come on line right at the beginning of heating season-we quickly found out that our assumptions of how much outside air would move through this building functioning passively and how much was actually circulating were a little bit different.
To really figure out how air is going to move from inlets in the offices to outlets in those conference rooms-and this is really an integrated design challenge because there are code issues that you have to deal with, which comes back ultimately to the architectural designers-we need to have a way to transfer air from multiple rooms-transoms, use of hallways, open doors and ultimately out outlets. The complexity of the required airflow is significant and you really need to get the whole team sitting around the table and engaging in a series of discussions of how smart your air is going to be (or maybe not so smart).
Ventilation in the offices is done passively. So, the offices are actually not served by heat recovery ventilators, all the windows are operable, and all of the office occupants have control over a dedicated air inlet, as well. So they can use both windows and their inlets to bring in fresh air as needed.
KD: The whole issue of people having a level of expectation for what you can accomplish in a passive building is really an important one. I just finished the design for a building in Hawaii and a couple of things hit me in the process. One, is that Hawaii has a temperature that is essentially always in the comfort range. They get a little more humidity sometimes than we're used to-and it may get up to 85 sometimes, or down to 65-but typically it's a ten degree daily temperature range. I was stunned by two things. Most of the buildings are air conditioned and not only are they air conditioned, but people were wearing sweaters inside the buildings. There's a real need for people to realize that they can be comfortable in relatively benign conditions without a huge mechanical plant.
By Jeff Cole, Konstrukt, Inc. for NEEA's BetterBricks.
Photos of Mount Angel building are credited to Lara Swimmer Photography. Photos of roundtable discussion are creditied to Jeff Cole, Konstrukt, Inc.