What technologies are engineering firms and building mechanical teams utilizing to achieve net-zero energy performance? A recent panel of engineering leaders met to answer this question and more through a webinar, presented by REHAU.  

The discussion examined several zero-net-energy initiatives in the U.S. and Canada, showcased how building teams can push energy efficiency boundaries with excellent mechanical system design, and included personal success stories from panelists Cindy Cogil, principal and director of engineering at SmithGroup; Adrienne Johnson, associate engineer at Point Energy Innovations; and Cathy Higgins, research director at New Buildings Institute. Below is a transcription of the webinar’s first 30 minutes. To view the webinar in its entirety, visit https://www.news.na.rehau.com/l/29862/2020-08-07/8xydkk 

REHAU: Let’s give our panelists the opportunity to discuss any current projects they’re working on relating today's topic. Cindy, please tell us about your current projects. 

Cogill: I'm currently working on a new, 300,000-square-foot computer science and engineering academic building on Virginia Tech's new Innovation Campus in Alexandria, Virginia. It is one of the first buildings to be constructed in phase one of a new mixed-use innovation district. I'm also working on, and just completed design for, a new dental school that's going to start construction and resuming design on a new education building that's been on hold for the last five years. Lastly, I'm part of a multidisciplinary team performing a flood risk assessment for a private lakefront university campus here in Chicago. 

REHAU: Cathy, what types of projects are you currently working on? 

Higgins: I continue to work a great deal in the topic of zero-energy buildings. We are now really focusing on in both policy and the market is zero-carbon buildings. So, we work a lot with moving the metrics and the dialogue to carbon instead of measuring just kilowatt hours. And it's really a great progression in my long time in this field to see that the forward-facing language around the reason we all do any of this work is to reduce environmental impacts — associating the energy with the the carbon. I'm working on a technology roadmap for the state of California, and I'm really enjoying conducting emerging technology research on some shading technologies in Southern California. There, we have two large office buildings, and we're integrating the lighting fixtures with automated shading and a small amount of HVAC retrofits. We’re finding this is a great opportunity to blend thermal comfort and visual effects with daylighting operations.  

REHAU: And lastly, Adrienne, how about your projects? 

Johnson: First, thank you so much for having me. It's really an honor to be on this panel and to be speaking to you all today alongside these incredibly brilliant women in our field. I would like to share some information on a couple of projects. The first project is one I'm proud of and worked really hard on. Our firm, Point Energy, recently won an international design competition, the San Francisco Affordable Housing Challenge. Our team received the BB Green Award for sustainability. The design that we submitted features a lot of low-carbon strategies, including mass timber construction, and was also an all-electric-and-distributed mechanical and plumbing system. And then, of course, we utilized on-site renewable energy.  

I'm also in progress on another mass timber project. This is an office tenant improvement for a tech company located in San Francisco. This will also be an all-electric design but with VRF. And this was a particularly exciting project because the core shell design, which was done before we joined the project, initially featured a gas-fired domestic hot water heater, but we were actually able to convince the client to prioritize reducing carbon emissions. They negotiated with the owner to switch out the gas-fired boiler for an electric water heater. It was unfortunately not the CO2 heat pump that we wanted, but it was still a pretty big win. The owner also able to save the cost and headache of putting in the gas line from the local utility. 

REHAU: To begin our discussion, we'd like to highlight several of the cities in North America that have taken clear actions to achieving zero-net energy within their buildings and communities. The first city we're going to look at is San Francisco. San Francisco is at the forefront of regional, state, and national climate action. With its energy watch program, the city has saved a total of $25.8 million in utilities and reduced energy demands by more than 25,300 kilowatts. Next we have Minneapolis, which is a leader in building energy efficiency. It adopted is commercial benchmark ordinance in 2013. This allows building owners and cities to track energy and water usage to determine the opportunity for improvement. Lastly, we have Washington, D.C., which is turning its attention to upgrading existing buildings and designing new buildings in order to reduce greenhouse gas emissions. Around one-in-five buildings in the districts will undergo some sort of energy improvement by 2031. Turning to our panelists, what are significant zero-energy trends that you've noticed in various cities and states? Cathy, do you want to start us off? 

Higgins: Definitely. Thank you for that overview. I look at this topic of building zero-net energy in a synergistic way between policies and the market. On the policy side, there is definitely a ton of movement, as you’re showing here. Some other examples include the Bloomberg Foundation, which founded 25 cities under the American cities climate challenge. We're working with six of them. So, we’re not just talking about isolated cities making progress on their climate action plans, of which you cannot meet those metrics if you don't do buildings’ energy reduction, because buildings are either equal to or slightly ahead of transportation, in terms of greenhouse gas emissions. So, we're in the buildings market, and we've got to address buildings. Then, you've got aggregated sets of buildings, such as those under the Bloomberg American Cities Climate Challenge. Then, you've got big players, like California and New York. New York's got a carbon neutral roadmap to take its entire economy carbon neutral by 2050. And California is just really leading the way.  

In terms of the building stats, which is what I'm cued up to speak to, let me just give you an image of what's going on at the market side of buildings. Regarding zero-energy trends, we do a status report for the last 12-15 years, have tracked zero energy in the building sector, and we keep lists that are available on our website. We have lists of every building’s name and address so that engineers can replicate and use those names to say, “Hey, where's an office in Minneapolis, or is there anything in Boston, or what do we got down in the south?”  

So, this aggregated sum of tracking lists in our database shows that we have more than 600 buildings representing 70 different building types. Fifteen years ago, I had to tell you a story about a small little building at Oberlin College that did a little demonstration on a zero-energy building. Today, we have 70 building types. These are dominated by three major building types: education, office, and multifamily. Those three sectors make up over one-third of the energy use and floor space in the United States. So, we are hitting some very important target markets. And most of these were driven by some kind of advance in policy. So, if we get policy going at the same time the markets are participating in building these zero-energy buildings, that's fantastic.  

We have buildings on the map in every climate zone. It's not just mild climate zones, because we're talking about mechanical systems in Canada, the provinces, British Columbia, every climate zone and in 45 states. They're not just small buildings either. Twenty-five percent of this database is greater than 50,000 square feet. So, it's a very diverse distribution of building sizes and types of buildings. And then, lastly, what I really get excited about is when you see that it's not just public buildings leading the way anymore. About 45% of these buildings are privately owned, and 27% of them are for-profits – so privately owned structures. So, we're seeing expansion into economic drivers to make a decision on the private sector. And, lastly, regarding existing buildings, 25% of these buildings are renovations. So, you can't tell me you can't get there in any building type in any location.  

REHAU: Adrienne, in California, electrification is a big topic. Can you talk with us about what this means practically and how this technology is changing your work in that state? 

Johnson: Definitely. As many people on this call probably know already, when we're talking about electrification, we're talking about switching our space and water heating and cooking technologies from fossil fuel combustion options to all electric ones in order to take advantage of our increasingly renewable electricity sources. And here in California, our grid is already over one-third renewable. Even at certain times of the year, we have periods where it actually gets quite close to, or a little over, 100%. So, electrification of our buildings is actually becoming much more critical and, in many ways, attainable. A lot of cities, like Berkeley and San Jose, and institutions, like the University of California, which I have done a study for, have actually banned on-site fossil fuel combustion right now from new construction. They're not waiting for our 2030 building code, which is slated to require all new commercial buildings to be zero net energy. For a firm like ours, this is pretty exciting. We've always focused specifically on zero-net-energy projects, which are, by nature, all-electric, and we're able to apply those principles readily to all the projects that we're working on. Pretty much 100% of our projects are all-electric. We're also finding that as this topic is gaining more ground, our clients are a lot more receptive to all-electric technologies. Some of the really big tech firms that we work for are actually now putting induction cooking in their massive campus cafeterias. Owners that we work with on multifamily projects are no longer really asking, “Why would you do that?” when we suggest they use an air-source heat pump for domestic hot water. And, we're also finding the mechanical contractors that we work with are a lot more familiar with systems, which leads to lower risk for them. And, in turn, owners get better pricing for these options, which is really going to be a requirement for this trend to continue. 

REHAU: Thank you for your insight on zero-energy trends. Next, we'd like to discuss how building teams can push energy efficiency boundaries with mechanical systems design. What do you think are some ways the design process can support both high performance and cost effectiveness? Cindy, would you like to tell us about where you start when you design a project? 

Cogill: Sure, thank you. You've all heard the saying, “You can't manage what you don't measure.” I think there's some really important first steps for any sustainable design project. And it starts with an energy benchmarking climate analysis and shoebox modeling to kind of understand your energy end use and where to target. Your energy building is going to target everything, but you have to kind of understand prioritization. It's really important to do vision and goal setting with your clients early on, but before any kind of detailed analysis can be performed, it's really important to understand the data input parameters. And, as architects and engineers, there's kind of only so much within our control. There are things that are not within our control, that are kind of under the purview of our clients and occupants that impact how energy is consumed as well as the infrastructure for renewable energy systems that you need to invest in to counter your consumption. These things have to do with how and when occupants use the building, such as occupancy schedules. Are they using the building late into the evening or on weekends? What are their expectations for indoor design conditions? Where is their comfort level within the thermal comfort chart? And what is their dress code policy? Are they suit-and-tie business attire or are they more casual attire from a dress code perspective. And then, lastly, we should consider plug loads and owner-provided equipment. Do we know what our clients are bringing into the building? Are they using laptop-based computer technology, or are they still using desktops? So really kind of getting at and understanding some of these things that we don't have control over is going to be really important to understanding the energy profile for their energy building. Because we have to remember that their energy buildings are based on actual energy use and not modeled energy. So our models need to be very predictive and as accurate as possible so that we're not grossly oversizing our renewable energy infrastructure — but we also don't want to undersize. 

REHAU: And what best practices or building technologies do you think is underutilized in zero-energy design? 

Cogill: So, I know Cathy already talked about the wide range of building types and scales, but they tend to err on the side of smaller scale, smaller height buildings, especially those that are trying to generate power on-site, on the roof, or within their site boundaries. So, in my opinion, the most underutilized tool in our collective toolbox is the thing beyond the individual building, and it’s the scale up. In my mind, this means designing building systems that enable energy to be more easily repurposed within a building, between buildings, and between buildings and the earth. And this often relies on technologies that heat at lower temperatures and cool at higher temperatures. 

REHAU: Adrienne, what else would you add about ensuring affordability when designing an efficient mechanical system? 

Johnson: I definitely second what Cindy said about measurement and making sure that you have an accurate energy model in order to be able to predict the building's energy use. I do a lot of energy modeling on a day-to-day basis, and it is a lot harder than you would expect to get really accurate information. But as far as affordability goes, I would say that it's really critical to, even know where mechanical engineers, consider the building envelope as a tool for designing the most efficient and affordable mechanical system. If you put in time early in the design phase and work with the architect to get a well-insulated envelope and high-performance glazing (and ideally less glazing as well), you can design a much smaller and, therefore, less expensive system. And you can also potentially afford a more premium type of system, like a hydronic system, but you don't necessarily have to go for top-shelf, premium systems in order to design a low-energy building. For example, and I will say in San Francisco we have a very specific climate, but on some of our multifamily projects we've been able to combine a really high-performance, well-insulated envelope with lower-cost, off-the-shelf-type ERV. We’ve found it possible to design really comfortable and highly efficient residential spaces with just baseboard electric heating. And this is at a fraction of the cost of other high-performance systems. It’s also really critical for mechanical engineers to pay close attention to principles of low-friction design, especially for ductwork. But, if you're able to do that, in some cases, if you go for an air-based system, you can potentially be close to the efficiency of hydronic systems. If done very well and very carefully, it's possible, and it can be a lower initial cost as well. 

REHAU: Thanks, Adrienne. You've also had some experience designing zero net energy buildings in other countries on an extremely low budget. What are some of the lessons you've learned during the design and construction of the Parkwood Tech Center that can be applied here in North America. 

Johnson: I would say that was a more extreme version of the concepts I was describing before. That was an extremely low budget project, literally like $30 per square foot. And we had to fundraise the money ourselves. So, every dollar we spent on the building meant fewer programs for students and community members that would ultimately use the building. So, we had to make a lot of hard choices there, but we essentially chose to design out our mechanical system entirely, except for the exhaust in the bathroom and the PV inverter room. And, fortunately, this was in Cape Town, which also has a relatively mild climate. People there are also much more accustomed to temperature variability. But our main focus needs to really emphasize passive systems as much as possible. So, we need to be thinking about daylighting and how we're going to use thermal mass, what types of insulation were available, and, of course, opting for natural ventilation.  

To view the webinar in its entirety, visit https://www.news.na.rehau.com/l/29862/2020-08-07/8xydkk