U.S. Department of Energy - Energy Efficiency and Renewable Energy
Building Technologies Office
Design and Planning to Create More Energy-Efficient Buildings Video (text version)
Below is a text version of Paul Torcellini, principal group manager for Commercial Buildings Research at the National Renewable Energy Laboratory, discussing the importance of design and planning for more energy-efficient buildings. In addition to this text version of the audio, you can also watch the recording (WMV 17 MB).
I'm Paul Torcellini, principal group manager for Commercial Buildings Research at the National Renewable Energy Lab. I want to talk about goals and setting goals, something that is crucial to get energy efficiency to work, and yet often overlooked in many projects. Design is all about making decisions, and sometimes we make the right decision for energy efficiency, and sometimes we don't. Sometimes it looks like the pieces go together.
My son is holding up a puzzle of the United States, and I put it together the wrong way. He knows what the right way is to put the puzzle together, but I put it together such so that the states don't quite match up. In fact, it's quite amazing to me; I could take this puzzle and put it together the wrong way. But we do this all the time with design. We take all the pieces, and we don't necessarily put them together in a way that makes sense for all the goals in the project.
Design is about making decisions. If we look at what the potential is for buildings, people often today are talking about zero-energy buildings—that is, buildings that are designed to produce as much energy as they consume. That seems like an impossible feat for hospitals. And in some ways it is. They tend to be dense. They tend to be multistory. They have a lot of equipment in them that would have to be offset by renewable resources onsite—something that seems out of the realm of possibilities.
When we look across the entire building stock, it currently uses about 90,000 BTUs per square foot. If I took those buildings and leveled all of them and rebuilt it according to the current codes, we could save almost 20 percent of that energy, or get it down to about 70,000 BTUs per square foot. If I took those buildings, and as we talked about in the optimization, applied an aggressive set of energy-efficient strategies; that would be daylighting, better energy efficiency, or better envelope design, better heating and cooling equipment—the whole gamut of energy efficiency—I could drop that number in about half to 40,000 BTUs per square foot. If I then covered half of the area of those buildings with floatable tag panels, I could reduce it another 75 percent, or to about 12,000 BTUs per square foot. It's not quite zero, but it's a whole lot closer to zero than where we are today at 90,000 BTUs per square foot.
The real catch on this, though, is that hospitals don't have to take that entire burden. We've got lots of other buildings out there. The catch is, everybody is responsible for helping change how buildings are viewed and how they use energy in this country. We often talk about the business case for energy efficiency. We've got to be somewhat careful about how we use this term because people make decisions every day. Sometimes those cost us money, sometimes they don't. People tend to buy what they want to buy. They tend to justify what they want to justify. Setting goals are important and quite often the business case will follow if we set the goals.
It is possible to create a low-energy building, with energy savings—substantial energy savings—and do it at a cost-neutral point. That is a perfect business case. For any project there actually is an optimal solution; that is, a solution that will maximize energy efficiency for a set number of dollars. There's only one solution that kind of fits at the top of that pyramid. Code is at the bottom of the pyramid. There are lots of different solutions, and those different solutions all use different amounts of energy. The key is, how do we get towards the optimal, with still giving some design flexibility?
People don't often want that optimized solution. They want some design flexibility; they want some mechanism to show that the building has some architectural merit on its own. There's a lot of room for growth in this area and a lot of room for looking at more energy-efficient solutions. Rules of thumb are quite often used to do better than code. We can usually achieve 10 to 20 percent energy savings with rules of thumb—proven methods for getting energy efficiency. But they won't get you to the top of the pyramid.
As we get closer to the top of the pyramid, we need to engineer more solutions. We need to use energy simulation models to help us fine-tune those solutions. If I do lots and lots of simulations, I start to get a feeling for that building and how it will behave when it's actually built. There are optimization algorithms available that will take thousands and thousands of different design parameters, run those simulations looking for those optimal solutions. It is always better to spend more money and effort on design, and less effort and money on the construction. Design is critical to getting an energy-efficient building, and simulations are a part of that.
One of the things that's important to consider are plug loads. Plug loads are often not considered as part of the design process, but they are an important part of the design. And examples might be, the equipment that's specified for a building; the elevators they get put into the building; all the other things that get plugged in as part of the process. Those should be planned for and the most energy-efficient equipment should be specified. It is important to look at the areas of the hospital that are not occupied 24 hours a day, and look for strategies to turn those things off. Turn the plug loads off. Turn the computers off. Put the elevators in standby modes. Looking at medical equipment that is not used 24 hours a day and asking the question, "Can that equipment be shut off, and how will that impact my overall load?"
It is amazing, when we look at buildings, that often 70 percent of the year, they're really not occupied to a full intensity. We can't often recommend a specific technology that can be used in order to get energy savings. There are really no set solutions.
There are three key points I want to leave you with today. The first is that energy savings is the core to sustainability. We make design decisions every day, and those design decisions are going to be here for a very long time. Buildings are here for a long time, and those decisions we make today will mortgage our energy future. The second key point is to set measurable energy goals that engage the entire team. I cannot stress enough how much the measurable part is important to us. And finally, that energy savings is easier and cheaper than producing more energy.