Presentation on theme: "The Need For Systems Integration with Passive Strategies"— Presentation transcript:
1 The Need For Systems Integration with Passive Strategies John Nelson, Architectural Energy CorporationDavid Banks, Cermak Peterka PetersenRob Slowinski , Architectural Energy CorporationI would also like to credibly mention Michael Holtz. He provided critical reviews, guidance and ideas.
2 Learning ObjectivesReview the drivers for passive architectural strategies, and the status of the industry in regards to adoption of their principles.Review the principles of natural ventilation and passive conditioning.Present examples of how projects overcame barriers through integration. Our learning objectives for today are to review the drivers for passive architectural strategies, and the status of the industry in regards to adoption of their principles.We are going to specifically highlight the principles of natural ventilation and passive conditioning as they are less commonly used. Unfortunately we won’t have time to cover daylight in depth, but there are a lot of other good presentations on that topic.And we will also end by presenting examples of how projects overcame barriers through integration.
3 We’d like to begin by defining passive strategies We’d like to begin by defining passive strategies. These images by TransSolar help visualize different approaches to design. One targets sustainability through tacking new technologies onto the same old model. It still makes its own rules, which is only possible through burning fuel. The other harnesses the rules of nature, through intelligent design.By passive strategies, we mean taking advantage of natural resources with architecture to meet loads, whether fully or partially, through daylight, natural ventilation, and passive conditioning.By systems integration, we mean using mechanical and electrical systems which build off these same principles, and can scale back significantly when the resources are available.It’s a complex issue and we don’t pretend to have all the answers, but we do aim present a case for why this topic is ripe for innovation in energy savings and also to connect the dots on some of the good work that has already been done.Images by Transsolar
4 State of the Industry & Planet: Trends Graph by Rocky Mountain InstituteGraph by American Center for ProgressWe initially intended on beginning with a section on climate data updates, and the environmental drivers behind net zero. This is why the topic is important and boundaries need to be pushed. Unfortunately we don’t have the time to do it justice. So in the backdrop of these images, we are just going to show two trends. On the left is what energy use has done and the top line is the future projection. On the right are the reductions scientists tell us we need to curb climate change. The middle range is for 2 degrees Celsius.These trends are obviously going in opposite directions. So there is a gap between where we are, and where we need to be.But note that the future projection, the top line on the left, is not as steep as the past use was. A closer look at that inflection point is very interesting.Muir Glacier, Alaska 1941 Photo by W.O. FieldMuir Glacier, Alaska 2004 Photo by B.F. Molina
5 State of the Industry & Planet: Trends The top three lines are energy projections from 2005, 2007 and You can see that initially the rate of change was expected to rise at a similar rate to what it had been doing. But then, in each new assessment the projections dropped. The orange line is the last update in 2011, and it’s still expecting a rise when we really need to be solving the problem, not adding less to it. But still, there is a change in trend.2030 challenge is claiming this as sustainability taking root. Really, this is kind of amazing when you consider the scale of this industry, and what is going on.Let’s take a deeper at what we are doing well at to already change a trend, and what we haven’t yet tackled.Graph by 2030 ChallengeData: Energy Information Administration
6 Paradigms Overlook architecture’s affect on energy use Monolithic TemperaturesTrade offs between peak and efficient normal operationWe have been good about embracing efficiencies within the same systems, which is good but it isn’t getting us to the reductions needed and there are some paradigms that should be questioned.In that, we still try to treat everything mechanically, and often ignore architecture’s effect on energy use. Both in penalties for bad design such as excessive heat gains, and in missed opportunities for architecture actually meeting loads.We try to maintain near monolithic temperatures which doesn’t make sense in the larger context. Meanwhile, research is actually showing there are more factors that affect comfort than we currently give credit to. This, and behavior, are topics of study within themselves that open doors to passive strategies.And designing for peak conditions still often means we design buildings to operate inefficiently normally. This isn’t just a matter of oversizing, although that is very important.But we select systems that meet peak loads and that is often the end of the story, even if a much more efficient strategy could meet most normal operating conditions.A project we’ll showcase later is in New Orleans. Hot and humid comes to mind. But the team wanted to ensure the very nice and extended fall and spring could be taken advantage of. And through natural ventilation, the building enjoys healthy high fresh air rates with low energy use for much of the year.Or, a great example in our climate is evaporative cooling, which may fall short of peak loads only several days a year, but is substantially more efficient than air conditioning. Given the hundreds of thousands of dollars these buildings cost to run each year, you would think from a financial standpoint that efficient normal operation would be the starting point, and whether or not you want to add a chiller to supplement 7 days a year would be what’s considered an add.Photos by:James Balog
7 Turning Momentum Proof of concept Loads of research available 2030 Challenge commitmentsRestlessness in professionalsOn the brighter sides, we are never trapped in old paradigms’ unless we give them the power of being in the present, and some projects have broken through the barriers and shown us the possibilities. This could suggest we are on the brink on a serious change as these strategies move from proof of concept towards best practice.There is also more publicly available research supporting passive strategies than ever before.Major firms have committed to the 2030 challenge, which requires serious reductions in carbon. These commitments represent a growing sense of environmental urgency.And this sense of urgency is resonating with a growing number of professionals and owners. Some are getting tired of half measures, and solutions are being worked on everyday.For the same reason, that being awareness of this environmental imperative, there is a growing demand for net zero in the marketplace. It’s becoming clear this is a serious competitive advantage to those that can design this way.Photo courtesy of NREL’s Photo Exchange
8 Passive Strategies: Potential & Adoption DaylightNatural VentilationPassive ConditioningTotal US Office Building Energy UseSource:Energy Information AdministrationThis pie chart is a quick reminder of where energy goes in our buildings. There are still the energy uses which are functions of what you do in the building. But everything that ‘runs the building’, that makes it a comfortable, healthy, usable, and lit space, is what passive strategies can treat.Daylight is generally well embraced but is not always done right. When solar heat gain is controlled, it is the coolest form of light. And because of the sun’s path, solar heat gain can be brought in intentionally when needed. The design solutions for daylight are often synergistic with natural ventilation. Natural ventilation is typically designed to meet loads under minimal natural forces. But at other times, it provides very high fresh air rates that are essentially mini flushouts. This in a way hits the reset button on IAQ by removing pollutants. And while there are savings in this free air for ventilation, the larger savings potential of natural ventilation is in exploiting the free tempering of a building’s mass which can contribute towards a thermal balance.Graph courtesy of Wikipedia
9 Photo By Tom ArbanThermal Inertia‘during spring and autumn, lightweight buildings may require both heating and cooling over the diurnal cycle, whereas the thermally heavy buildings can maintain comfortable internal conditions without either supplementary heating or cooling.’ – BRE Digest 454‘Most modern buildings are structurally heavy but thermally light. Widespread use of carpets, floor voids, false ceilings and plasterboard wall liners, all of which effectively insulate the structure from the environment’– BRE Digest 454‘Thermal storage techniques absorb heat during peak periods of excess gain and store it until it can be discharged later.’– CIBSE Mixed Mode Ventilation AM:13Every building begins with mass, but we add finishes which isolate it. Our buildings fluctuate from internal loads quicker than they would with the mass exposed. To make it worse, we typically treat everything with air, which also has a low heat capacity. This is a very mechanically dependent way to make our buildings.When we expose mass and allow it to absorb internal gains, we can either reject the heat for free at night in the summers when we need cooling, or hold it to reduce morning warm up in shoulder seasons. NREL calls this a thermal battery. It’s basically allowing the building to do some of the work.
10 Approach of Thermal Balance -These are two popular images with sustainability;-Many of you have probably heard of these termite mounds that stay a constant temperature inside. Outside fluctuations go between 37 and 107 in this desert, not exactly a forgiving place, but they’ve found a way to temper their nest without fossil fuels.-The image on the right is Mesa Verde. The Anasazi tribe built at this location because all of the high summer sun is blocked, and all of the low winter sun gets in. The mass helps with warmth in the winter and cooling in the summer. Now, this place would by no means meet the narrow comfort band of ASHRAE 55. But if they needed supplemental fires for warmth, they weren’t as big. And that is the lesson we can draw.Images courtesy of Terrapin Bright Green & Rocky Mountain Magazine
11 Quality Chart by Rocky Mountain Institute - Passive strategies align our push for serious reductions in energy use with QUALITY of the built environment. This concept is central to sustainability. This space is amazing. The value of it is self-explanatory. Because we like daylight, because we like fresh air, because we like connection to outside; we respond to this kind of space.-There have been numerous independent studies on the effects of daylight, and they consistently show an increase in productivity, sales or performance. And natural ventilation gets away from the trade-off of reduced energy by reduced ventilation. Ventilation is inherently good, but when it’s coupled with burning fuel on and off site it’s not so good, so we come up with complex equations to balance acceptable pollutant levels inside with acceptable pollution rates outside. But when outside air is abundantly available and can be thermally beneficial, why not use it for good IAQ.-Some people don’t believe the productivity gains. That is why this image was intentionally chosen. It is a private company’s headquarters. I would say they believe it, embrace it, and are doing alright.-We in the industry see the cost of the building; RMI’s chart reminds us that the larger picture to a business is the cost of salaries. This is important to keep in mind as we advise our clients. We get pigeon-holed into trying to justify green on not just a purely economic level but within a 1% sliver of a business’s cost, but there is an elephant in the room that sustainability most definitely has an effect on. By solving energy problems through passive design, we enhance the built environment and add to quality of life and the bottom line.If you see architecture as an important cultural asset, this is already intuitive. Our energy problems are not just technical problems, and sustainability is not just a technical solution.-[Segway: Next, we would like to offer a few perspectives about how teams can approach designing passive strategies.]Chart by Rocky Mountain InstitutePhoto courtesy of World Architecture Festival
12 Integrated Design“Integrated design is both a process and a result” -Michael Holtz, FAIAThis first thing to remember is that integrated design is both a process and a result. The result is the intention of the process. Commonly, we get caught up in the buzz word and miss the real point. It is about making a better building.Integration is how high efficiency is achieved cost effectively. Integration is also how passive resources are taken advantage of at whatever level they are available, while still having systems which will ensure comfort. Having everyone at the table is a best practice for reasons beyond sustainability. For it to affect sustainability, you need to be actively looking for integrated results and energy savings. Making one element serve multiple functions, or one design aspect serving both an energy balance and a program function is what we are talking about.Chart by Rocky Mountain Institute
13 Climate & Location Analysis To capture integrate results, some of the first things to look at are the climate charts and internal loads so you know what kind of solutions to try.This needs to be analyzed very EARLY, so it can inform the architecture at it most conceptual level. Think about what kind of resources you have. Think about what kind of external and internal loads the building will need to deal with. What is the context of the location? What kind of light or shade is there? How can it be used? What kind of prevailing winds are there? Take all the climate data into consideration, so you can think about how to create a building, for the place that it is going to be. With this knowledge, you can then approach the buildings loads as a design problem to solve.This takes an interdisciplinary approach. Architects need to know the loads in order to treat them correctly, and mechanical engineers need to understand what solutions are being met architecturally. This is the essence of integrated design with passive strategies. So, architects play a more significant role in the engineering, and engineers play a more significant role in the architecture.Image courtesy of World Architecture Festival
14 Testing Concepts: Modeling Push boundaries on paper first: “Only a fool views success as never having been wrong” -Jason McLennan (Living Building Challenge creator)Test our strategiesBecome informed to enhance / optimize designOptimize glazing amount = upfront and operational savingsThe image on the left is a mechanical room. This area is used for intentional solar heat gain. It is building in Canada where it gets to negative 35. There is not heating system beyond this area and radiant heating in the slabs.It brings up a question, if passive strategies can reduce loads, would you rather put your money into architecture or mechanical and electrical systems?Components have a short life relative to architecture.Retrofit is inevitable.This space makes the building, and it was shaped by energy decisions. We already do a lot of variations in buildings as a part of solutions to other problems and because we don’t want our buildings to be giant boxes. How financially sound is it for cost conscious projects to do similar changes in massing, for purely aesthetic reasons, but then ignore passive strategies?Architecture is in many ways shaped by eras, in that once an era begins, the issues are worked at until they are mastered. During periods when structural engineering was being pushed, architects crossed disciplines deeply with structural engineers and solved amazing problems, and the structure shaped the architecture. These concepts of crossing disciplines or making the same element serve multiple functions is not new sustainability, it is just incredibly important to sustainability.Some architects still come up with a grand design, as an expression of art not bound by energy, and let the engineer figure out how to make it work. That is getting recognized as hubris more often, and it seems to be a function of an era that we are starting to turn the page on. We now have different intentions in buildings and in our architecture, driven by a need to reduce energy. It is a great opportunity for better architecture. What has more boring than placing the same building anywhere, which is only possible through excessive energy use. We used to have to use passive strategies to make buildings comfortable. In today’s time with modeling, automated controls and deeper knowledge, architects can reduce loads in elegant ways. People respond to this function in design and connection to the outdoors. We can let it inform our architecture, and enrich our architecture.ALT: In today’s time with modeling, automated controls and deeper knowledge, architects can reduce loads in elegant ways. People respond to this function in design and connection to the outdoors. These solutions can inform and enrich our architecture, and bring together deep energy savings with an aesthetic that describes abundance instead of reduction.Modeling by Zack Rogers
15 Eras & Intentions Manitoba Hydro Headquarters, Photo by Eduard Hueber The image on the left is a mechanical room. Nicest mechanical room I’ve ever seen. This area is used for intentional solar heat gain. It is building in Canada where it gets to negative 35. There is not heating system beyond this area and radiant heating in the slabs.It brings up a question, if passive strategies can reduce loads, would you rather put your money into architecture or mechanical and electrical systems?Components have a short life relative to architecture.Retrofit is inevitable.This space makes the building, and it was shaped by energy decisions. We already do a lot of variations in buildings as a part of solutions to other problems and because we don’t want our buildings to be giant boxes. How financially sound is it for cost conscious projects to do similar changes in massing, for purely aesthetic reasons, but then ignore passive strategies?Architecture is in many ways shaped by eras, in that once an era begins, the issues are worked at until they are mastered. During periods when structural engineering was being pushed, architects crossed disciplines deeply with structural engineers and solved amazing problems, and the structure shaped the architecture. These concepts of crossing disciplines or making the same element serve multiple functions is not new sustainability, it is just incredibly important to sustainability.Some architects still come up with a grand design, as an expression of art not bound by energy, and let the engineer figure out how to make it work. That is getting recognized as hubris more often, and is seems to be a function of an era that we are starting to turn the page on. We now have different intentions in buildings and in our architecture, driven by a need to reduce energy. It is a great opportunity for better architecture. What has more boring than placing the same building anywhere, which is only possible through excessive energy use. We used to have to use passive strategies to make buildings comfortable. In today’s time with modeling, automated controls and deeper knowledge, architects can reduce loads in elegant ways. People respond to this function in design and connection to the outdoors. We can let it inform our architecture and enrich our architecture.Manitoba Hydro Headquarters, Photo by Eduard Hueber
16 Natural Ventilation & Adaptive comfort Ventilation ObjectivesFresh Air (< 2 ACH)Thermal Comfort (> 2 ACH)ProductivityLearning ObjectivesUnderstand the physical principals of natural ventilationKnow how to take advantage of these principalsGain familiarity with tools used to predict performanceNatural Ventilation & Adaptive comfort
17 How to Ventilate Naturally Air flow from:stack effectwindsRelated issues:thermal massheat loadsexpectationsNew image probable – one with “aspirational arrows”?
18 Stack Effect Driven by temperature difference Height of column of air gravity
19 Wind Driven by Wind speed Pressure fluctuations due to building shape and surroundingsWind speed will overwhelm stack effect at 3-10 mph. This is most of the time.
20 Seasonal and diurnal wind directions Time of day
21 Air Flow Simulations Nodal model/ Building Energy Sim For the whole building“Coupled” important if stack effect is a big partComputational Fluid Dynamics (CFD)For details of a single room or building segmentSimulates a specific situationBoundary Layer Wind TunnelFor outside the buildingDoes not predict indoor flows
22 Boundary-Layer Wind Tunnels A boundary layer wind tunnel recreates the turbulent winds of the lower atmosphere in a controlled environment.
27 Personal ControlOur primary objective in this project was to examine the differences between individuals with relatively high and low degrees of control in the same naturally-ventilated building… While these two groups were experiencing similar physical conditions that influenced their heat balance, we found significant differences in their subjective response … While behavioral mechanisms are certainlysignificant in allowing people to adjust their personal comfort, psychological dimensions are also relevant to the degree of thermal comfort experienced.This emphasizes the importance of not just designing a building with a high degree of adaptive opportunity, but ensuring that all occupants have direct and easy access to those various means to control their own environment.Operable windows were, by far, the most used control. Blinds were used about half as often as windows, and ceiling fans or desk fans were used even less.Gail Brager, ASHRAE Transactions
28 Add a slide to show typical analysis result (fraction of the time you’re above 80% temperature at UCI arts, for example).
29 Add a slide to show typical analysis result (fraction of the time you’re above 80% temperature at UCI arts, for example).
33 Integrated Results: LEADING THE WAY Now we all know that many of these strategies and concepts aren’t exactly new, but it’s also pretty apparent that we as an industry haven’t been getting the most out of them. Now whether that’s due to a reluctance to move on from what we’re comfortable with or what… that’s up for debate. But to sort of conclude our presentation by tying them all together, these are some of the buildings that have achieved really great results by looking forward and relying on the science.Integrated Results: LEADING THE WAY
34 Integrated Results: Stanford’s Y2E2, CA Stack effect: 4 central atriaBAS and occupant-controlled natural ventilationExposed slabs integrate with architectureChilled beams well-suited for natural ventilation when systems are activePhoto by:John NelsonThis building at Stanford is a great example. The XXX,XXX ft2 energy and environment building, it’s slated to save 56% over T-24 code baseline.It’s naturally ventilated with 4 central atria to provide a stack effect. And it’s very purposefully integrated in to the building’s automation system, with roughly a third of the lower level operable windows electronically controlled (allowing strategies such as night purge ventilation). There are also user-operated windows as well.The architecture and massing is well designed with plenty of exposed thermal mass to temper the space.And the chilled beams are well-paired with natural ventilation for when the building is in active-mode.Image courtesy news.stanford.edu
35 Integrated Results: Stanford’s Y2E2, CA But what’s particularly interesting, and this is something that John picked up on while out at the Stanford campus, is that you can clearly see the progression that the University took when designing and building new buildings. The design of the X-years-older X building is particularly similar to the new Y2E2. The massing is the same, the courtyard/atrium design is the same. But there windows aren’t operable. It’s almost as if the Stanford officials were trying out the concept and proving it to themselves before going full bore with the natural ventilation.AND… right next to this building is a brand new one going up, which also extensively uses natural ventilation.Photos by:John Nelson
36 Integrated Results: NREL RSF, CO Massing for daylight = massing for natural ventilationExposed mass for passive integrated with radiantRadiant can use low grade heating & cooling (eg: solar thermal)Now this is a very local project that many of you are probably at least a little familiar with… it’s the new RSF facility at NREL in Golden.Now, it’s got a unique footprint, to be sure, and that’s based on some detailed analysis of the daylighting and proper solar orientation. But massing for daylight is also typically good massing for natural ventilation, and that’s exactly what the RSF takes advantage of.It’s got a good envelope of course, with pre-cast integrally insulated panels. But it also uses radiant heating and cooling to be able to take advantage of lower-grade heat, and even downsize equipment. (NREL notes that their mechanical costs for this building were below industry average.)What the radiant heating and cooling also does is allow RSF to take advantage of solar thermal heat production. NREL did NOT do this, but for future applications, this can be a viable strategy.Photos courtesy of NREL’s photo exchange
37 Integrated Results: NREL RSF, CO UFAD: Office flexibility, efficient ventilation, and exposed ceilings all with one strategyIndirect/direct couples well with ‘open’ buildingsTranspired solar collectorsThe RSF also uses Underfloor Air Distribution. For a space that needs to be highly configurable, UFAD works well, as all communications and other cabling can be below the floor, and the layout remains flexible. This also allows for higher ceilings, which is better for daylighting and also for natural ventilation.Much of the time this design provides substantially more fresh outdoor air than would be designed into a regular mechanical system. And the rest of the time, the building reverts to a minimum ventilation rate with 100% outside air.And those mechanical systems that were specified also work well with the design. Indirect/Direct evaporative cooling is great for Colorado we know, but it also tends to work really well with natural ventilation because it’s low-energy cooling.Displacement ventilation is a match because both displacement and natural ventilation work on principles of low pressure and stratification. Units operate as needed, and pollutants rise to the top of the tall space, keeping air quality high. An icon is even setup to appear on occupants computers when conditions are favorable to shutting down the entire system… saving significantly more energy than just a window sensor that pinches a VAV box closed.And in a cold climate like ours, energy recovery is very important during the wintertime. NREL takes this a step further by using passive pre-heating in the form of transpired collectors and an extensive labyrinth below the building, allowing the façade and building to effectively temper all incoming air. This doesn’t look much different than a typical metal wall panel design, but you’re getting two useful functions out of a single building element.Upper photo: John Nelson / Lower photo courtesy of NREL’s photo exchange
38 Integrated Results: Tulane University, New Orleans, LA New Orleans historic architecture with layers of shadingThermal zoning: designed for ‘open operation’ fall and springDaylight with good shading = low solar heat gain & low internal loadsThis example is important, because it proves that natural ventilation can be done in a humid environment. We all know how New Orleans is…hot and humid, right? Most designers might think “natural ventilation hot and humid… ick!” But this building does a good job of integrating both passive and active systems, and realizing that although it IS hot and humid during the summer months, New Orleans actually does have a quite pleasant… and LONG… swing season in both the spring and fall. A couple of key points:This building uses historic New Orleans architecture with lots of integrated shading, balconies and courtyards.It employs “thermal zoning”, such that some areas of the building are allowed greater temperature swings than others. And because of this and the swing seasons, the building operates in “open mode” for 6 months of the year.And as we see in many of these buildings, there is lots of radiant cooling and heating. With good daylighting and good shading, this combination of systems can really tackle even the harshest loads in harsh places like the Louisiana summer.Photo courtesy of Archilovers.com
39 Integrated Results: Muechener Tor, Munich Germany Photo courtesy of Wikipedia2 central stacks, 20 stories highNo mechanical ventilationSupply air conditioned with geothermal ‘air to earth’ registerFree cooling of exposed slabs and night flush is supplemented with radiant cooling from ground waterThis building is a great example, at least in my opinion, because it doesn’t look like there’s anything special about it. It’s a 20-story, 600,000 ft2 office building in Munich. But what it’s hiding are a couple of central chimney systems that intake and expel air with heat recovery. There’s no mechanical ventilation at all, and the stack effect is entirely reliable with this much height. The building’s got lots of exposed mass and radiant heating and cooling. In the summertime, when particularly hot days cause the need for further cooling, low-grade cooling is done with groundwater. And the supply air is preconditioned with a ‘geothermally-functioning air earth register’.
40 Integrated Results: Unilever Headquarters, Hamburg, Germany Area of high winds -> double façade/hybrid ventilationConcerns about exhaust from harborExposed mass/radiant heatingLarge atria is ‘building’s lungs’And to close, another building from Germany, this time the Unilever Headquarters in Hamburg. This building faces the challenge of being located on the water in a very windy area, so they had to get creative in order to protect their delicate shading system. The answer was a light double-skinned façade. It’s really a great solution, because it provides good indirect daylight throughout, proper solar control, and natural ventilation in an area where high winds would normally be problematic.The building isn’t 100% naturally ventilated, owing to concerns about exhaust from the harbor. BUT, windows are operable, and night flushing is integrated into the building’s operation.The large atrium turns a wide building footprint into a narrow one, conducive to both natural ventilation and daylighting.In total, the building uses ¼ the energy of comparable German office buildings, and provides a great connection to the outdoors, while bringing in the abundant light and breeze to meet it’s loads.Photo courtesy of World Architecture Festival
41 Questions? John Nelson, Architectural Energy Corporation David Banks, Cermak Peterka PetersenRob Slowinski , Architectural Energy Corporation