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Living Green in New York City

Mr. Pelli: I’m thrilled to be here, I guess in honor of the presentation this morning about the ensuing demographics. As a second generation Hispanic, I have to say my Spanish probably isn't really up to it, so I'll continue in English.

I want round out the story which you have been hearing from a number of different perspectives today; to give you a snapshot from the front lines of designing buildings with very, very ambitious environmental design guidelines and objectives and some of the challenges.

Over the course of the last eight years and building three different buildings at Battery Park City in New York we have looked at just about every technology out there. We've employed microturbines, we've got 45 percent fly ash or slag in our concrete mixture. We've looked at it and done it all. But we're really coming up against certain thresholds and are now trying to go back and look hard at the data, both the analytical data during design process and the actual operations of these buildings to find out what's working, where we have to go next with this. I think the next oncoming challenge is with the climate change.

Battery Park City is at the tip of Manhattan in New York City. It used to be in the shadow of the World Trade Center, which is no longer there. Marilyn's firm is designing a couple of new buildings, one which is completed and one which is underway. We have designed a few buildings starting in 2000, one is called The Solair, the second is called The Verdesian and the third os called The Visionaire. That's how they're known out there in most of the publications so I'm going to stick to those names, but I didn't have much to do with coming up with those names.

This was the result of Battery Park City Authority, which is a state organization, in the year 2000 making major policy initiative under Governor Pataki to let this portion of Manhattan be a learning laboratory for the construction industry in New York. They required a whole set of very ambitious criteria for the buildings. We were designing buildings to meet a voluntary program under the U.S. Green Building Council called LEED, which Larry just referred to and others have referred to before. This is a building rating-system where you want to get a gold star or a platinum star, a silver star. The voluntary program has had an enormous impact on the way that environmental design is characterized in this country.

Battery Park City took it further and actually made a number of things very prescriptive. They required photoble tanks. They required a water treatment plan. They required us to do a number of things that went well beyond what Lee did. And then finally, there was the green building tax credit, which was offered by New York State to help offset some of the costs.

There was a lot of overlap between slightly different objectives in this and a number of strategies which were in a sense given to us. We just had to figure out a way to implement them. Here is the building as it was completed with a photoble tank array both on the front and on the top of the building. Down at the tip of Manhattan the second building took place just behind it. Because it was the first it was watched with great interest. Here's an article from the New York Times in 2004 after it opened. It was a subject of great interest for technical reasons, for sort of intellectual reasons, but also for financial reasons. The development industry was looking very hard at this. There were another eight building sites that were going to come available, all these in yellow here, and they are going to have to meet the same objectives. Some developers felt that this would never fly. You never pay the increased premium costs.

Not only did we meet it, but it came on line because construction was stopped after 9/11 when there were a lot of vacant apartments down there due to the destruction of the World Trade Center. The building filled up quickly and at a premium and actually, a greater premium than the developers had even needed to amortize the additional debt. So it was a rousing financial success story.

Now, of these further eight buildings, they are all built or currently under construction. The development community has now adopted this as a standard for it from a marketing standpoint, the meeting of objectives for building new buildings. It's really becoming kind of an evolving standard of the industry.

There's a lot of attention to the exterior wall. I'm going to get to that point again and again because really, it's the oldest idea in the book but it remains the most potent. Also, what you do with your exterior has more to do with the energy profile for the building than anything else.

We looked at a traditional brick and block wall - Battery Park City requires brick. And we took it through some wind tunnel testing and through some computer simulation studies to understand how it functioned. We made about 50 modifications to it and came up with a new way to build a brick and block wall which performs better.

I'm giving you an idea of the range of strategies. This is a green roof, a planted roof, which basically means there is a soil layer which serves as insulation and it ejects heat in the summertime by evapotranspiration. It is amenity space.

This is a lobby, and I want to speak about the materials used which were selected both to be at a close distance and for their chemical composition. This is an analysis of where all the materials on the project came from. One of the issues that has come up is the transportation of materials which is often times the biggest energy costs in the use of those materials.

The only visible representation of the environmental objectives of the building is this photovoltaic array, which sits both on the front of the building and up on the bulkhead. It is wonderful, it's actually beautiful material and very sympathetic with brick and it's very granule, it's very modular. I think the photovoltaic array, while it serves as a symbol, actually creates a complicated relationship with what we believe the role of technology is in all of this. I think it was referred to earlier by one of our speakers that we're always of the belief that the next best machine is going to solve it all for us. In the notion of green buildings it really has become translated; our photovoltaic array is going to solve problems, it's going to produce all this great energy or the next generation photovoltaic array or the fuel cell, some technology is going to drive the energy solution for building usage in this country.

Technology is having profound affects in two categories. One of those is in the tools by which we design buildings. These are computer simulations through a piece of the exterior wall of the building. They're looking at temperature and they're looking at temperature flow, known as flux. That's a piece of the brick wall. There's some glass up above, glass down below. Here's the floor slab. And what's really interesting is we learn how the heat moves through a wall through these simulations.

Now, these diagnostics techniques didn't exist when people were building these buildings 20 years ago, barely even ten years ago. But through them you can take any form of construction and make a number of intelligent decisions about how to make it work better. That technology has been profoundly influential to how we design. SOM has been at the forefront of a lot of the good work with computer modeling to do very large-scale buildings and predict air flow and energy usage. So that's where technology has had a much bigger impact, frankly, than photovoltaics, which remain a very costly technology. It's not really something that in and of itself makes much sense. It uses a lot of materials which are then difficult to dispose of in the future.

So that was the completion of the first building. These pictures were taken from the river side where it gets a lot of sun, which is why we have mostly western facing photovoltaics because we don't have sun on the southern side.

From there I'm going to go to our newer building. Our newest building on the southern tip and is now actually employing a host of newer technologies, some modifications to what we've done on the first building. This one is called the Visionaire. It is no longer a brick building. We got a variance to do a terra cotta tile building, which is all integrated into a curtain wall which is a different way to build a wall than a brick and block wall.

You'll notice we have the photovoltaics there on top again. You notice it is a very glassy building; a lot of new architecture is trying to be very glassy. But it presents a fundamental conflict. What's the number one thing I need to know to determine whether this building is intelligently designed with regards to the environment? It is the percentage of vision glass on the exterior wall. For large-scale buildings, that will tell you more about how intelligently it is designed than almost any other number you can ask for because where you have the glass, you’re losing heat, you're losing cooling, you're gaining heat. It's much harder to control. It's the oldest idea; all architects prior to all of our free electricity, of course, knew this. We have to relearn it.

So to get a glassy building, this is what our client wanted. We had to work hard to actually have that glass covering up insulated walls. It is still glassy in appearance but it is only a couple percentage more in vision glass. Balancing that percentage is really critical. It is a big indicator to the performance of the building on almost any scale.

The selection of materials is also important. Getting in a lot of daylight but looking at naturally harvested woods, looking at materials that have a benign chemical composition is still an ongoing, critical investigation. A lot more products exist now compared to 2000 when we designed the first building. A wood block floor in the lobby again; a lot of natural light surrounded by trees. We face north and slightly west and to the west we have a lot of trees which provide shade. There is another green roof, amenity space with a beautiful view out to the Statue of Liberty. Underneath the hardscape there's a layer of soil which retains water and which also serves to cool in the summer. Photovoltaics again, integrated into the roof of the building. The terra cotta tile down more in the base of the building.

We have for all three buildings a water treatment plant. The fresh water comes into a water tank, comes through from flushing toilets, for laundry, and goes down into a water treatment plant that treats 30,000 gallons of water a day. That water is then supplemented by storm water, which is both retained on the green roof and in a storm water retention tank. That goes into a resupply mechanism for flushing toilets, irrigating the roof gardens.

What is the biggest user of water in an urban building? I never knew this until I went through this exercise. It is evaporation in the cooling tower. The evaporation in the cooling tower for this building is about 20,000 gallons a day through all the high season. It dwarfs everything else - showers, laundry, you name it. Has nothing to do with where the real water use in an urban environment is and raises some interesting questions about the use of water in urban environments. For example, we bring the water in frm tens or hundreds of miles away, through reservoirs and through watersheds, then we filter and clean it and for what use? For evaporation.

I don't think it actually makes much sense at the building scale. It's a very costly solution. We were mandated to do it. But as a distributed infrastructure strategy, I think it actually makes a lot of sense when we get into water issues. New York has abundant water. It's not critical. In the Southwest, though, I think this could be very important.

Now, looking at the energy use across the design of these three buildings, we looked at how they related to code. They were all about 40 percent better than code, but code is a very moveable target and a hard thing to define. We were much more interested in looking at it in an absolute way. So energy intensity is actually a better number. It's more like miles per gallon; it's an absolute, hard number. You can really look at well-performing buildings by their energy intensity. It's a much better indicator than their relationship to code.

Average energy intensity for a multi-family residential building in the U.S., according to the Department of Energy, is about 126,000 BTU per square foot per year. Our building in the Solair was better than that, but not nearly as much better as we thought it was. When we went back to investigate why, it was because the ventilation systems were bringing fresh air into the entire building and the water treatment plant was using a lot of energy. So again, from a policy standpoint you get into some competing objectives here about what's more important, the energy use or some of the other strategies. At Battery Park City, air quality was a critical strategy issue.

We actually looked very hard at the ventilation strategies for our third building and we were able to bring it down significantly. We were required to supply fresh air to every apartment. This is really much more of what you see in an office building than a residential building. We still have operable windows. We had to get into what that really means, what governs the supply of the air in a typical apartment. Here's looking at a plan of a typical apartment. Well, governing the supply of air was how much air you were exhausting. There is no requirement, no standards for fresh air supply in residential buildings in New York City. But there are standards for exhaust, which were designed about 80 years ago with tenements in mind to promote healthy standards so that you don't get mold; you don't get mildew; you get rid of food odor.

But all that was just sucking in air from the outside. Now, we're supplying fresh air. Well, we've got to balance the amount of air that's being thrown out. So we were taking this enormous amount of air and filtering it, humidifying it or dehumidifying it, bringing it into these apartments and while they were empty we were still ejecting that same amount of air at a constant 24-hour-seven-day-a-week basis. So it actually had a huge energy consequence doing that.

We got pilot approval from the Department of Buildings to calibrate the fresh air supply to what people need from fresh air supply standards - this is looking at Swedish standards, European standards and some domestic standards - so that we could then balance the amount of fresh air to the amount of supply better and start from the supply side, rather than how the exhaust side. In the final building we were able to actually create a kitchen hood that you could ramp up so that when you're cooking, you can get rid of the odors better and you can get a higher rate of exhaust in those buildings.

I know this is all a little bit technical, but I’m trying to illustrate the kinds of interrelated issues and complexities you get into when you have to design these kinds of systems. There are competing objectives. We were then able to also put heat-recovery systems on this and recapture a lot of the heat as it goes out the building to cool or heat the incoming air. So this is a view of the nearly final building.

I wanted to show you one last example. I'm focusing specifically on energy because again, this is where more and more of our focus is going. Let’s look at an academic building for a new business school in Champagne, Illinois, for the University of Illinois. It's a U-shaped building wrapped around a central common space, one very large open space in the center. Here is a panoramic view from within the courtyard with all native plantings except for one piece of lawn which the University still wanted so that students could sit out on it. Everything else is no-irrigation, native planting.

We were able to bring down the energy use of this building about 40 percent. The energy intensity numbers actually correlate to this pretty closely. Typical for the U.S. is about 60,000 BTU per square foot and this building is about 41,000 BTU per square foot. It was primarily through two strategies. One was in the lighting and the other one was through heating and cooling, which had everything to do with the exterior wall and therefore, being able to make smaller, more efficient mechanical systems behind the exterior wall.

We came up with a facade design strategy which was as much tied to ideas about lighting the classrooms as anything else. We had clerestory light. These were all blackout for presentations. We combined clerestory light with light shelves so we could bounce light deep into the room and then coupled that with various fissured fluorescent fixtures which were on dimmable ballasts so the lights could dim automatically when there's a lot of daylight. That allows for minimizing the amount of artificial light when you have a lot of daylight to work with. All of these are on a complicated sensor system tied to the central building management.

And again, here you get into the control systems. Technology use is making buildings more intelligent, making them more sensitive, making them able to better respond to the conditions that they have. This is another computer simulation, hard-to-read diagrams. These are plans of the classroom. These are what are called daylight autonomy studies, which allow you to study how far under different scenarios you can penetrate light into the room. By being able to do these studies we're able to calculate how much daylight will get into the room which allows the lighting engineer to design their lighting systems differently. You get the full benefit of that kind of analysis. Again, it's the use of technology as a diagnostic device and an analytic device, rather than as a product or as a piece of it.

Here is a photograph of a piece of the exterior wall. Here is where we have offices so we don't need clerestories. The wall is only about 20 percent vision glass averaged over the entire building. It's a very solid, very efficient wall which was achieved by increasing the amount of insulation in the wall and by having triple panes of glass. We have what's called the two plus one, because we've integrated blind systems into it. By making a very, very good envelope to the building and limiting the amount of glass, we were able to design significantly smaller heating and cooling systems. It's what Texas architecture was based on before air conditioning, right? You designed good walls, good, deep walls and you let it cool off at night and keep the cool in during the day. That's what we need to get back to, using that basic methodology. This is what's called the displacement ventilation systems, which is also very efficient.

We had very, very efficient exterior all around. That allowed us one flourish, one very large pane of glass to what we saw as the heart of the project. It's a reading room for the institution. The business school wanted a 24-hour environment where the students could get together. They wanted as much possible space as they could get. We created this room more along the lines of a reading room at a library than a formal atrium, which is in a sense surrounded by breakout spaces also on the balcony levels and the central staircase, which then connects all the stairs - the floors, the three main floors of the building.

I'm going to conclude with one last thing. I think I've been focusing a lot on what we have been charged to do, which is design these buildings as efficiently as possible. But there's something in the end, when you really look at the environment and buildings; we make the buildings the villain in some ways. You're talking about architecture using 50 percent of the energy. The line of the building itself is a pretty artificial line when you start thinking about environmental consequences. You have to think both outside of the line of the building and you have to think about the infrastructure of the land use planning within, which is the functioning of the building. The building is really the inheritor of a lot of other decisions, including whether you need to drive 20 miles to get to work every day, whether there's transportation, the utility systems around it, whether there's a good infrastructure for dealing with wastewater. The building can't be responsible for all of the infrastructure issues.

Just as importantly is what's inside the building. In the end, it's us. The buildings don't need to keep themselves warm, except very minimally. They're trying to keep us warm and us cool. And we, as human beings, actually are pretty adaptable animals at least up until about a hundred years ago when we decided we no longer need to be adaptable because we can heat and cool ourselves to within a degree. Now we have mechanical systems that use a great deal of energy to make sure that it never gets hotter than 74 degrees and never gets cooler than 70 degrees. One of the biggest things you could do to change the energy use in a building is simply to start looking at aspects of human adaptation.

The standards for comfort in America are actually much tighter than in England, in Europe and in Asia. Particularly the sort of tropical countries which have always learned to dress differently when it's really hot; when it's cold you wear a sweater. The energy use attributable to keeping it at 70 degrees rather than 69 or 68 is actually enormous and would largely overshadow many of the other things I've been talking about today. And with that, I'll conclude. Thank you very much.

speaker rafael pelli Speaker Rafael Pelli, Principal, Pelli Clark Pelli Architects, New York City. Photo by member John Gullett.