Greenbuild International is one of the world’s largest conference and expo events dedicated to green buildings. In October, the conference brought together industry leaders, experts, and frontline professionals in Los Angeles to share their pioneering practices and insights. I was inspired by the passionate and innovative experience in LEED, net-zero projects, and new products showcased at the expo.
GO NET POSITIVE
One of the most interesting sessions I attended was on a net-positive energy case study. Chatham University’s Eden Hall Campus by Mithūn is the first new university campus in the world to be built sustainably from the ground up, featuring full-cycle water recycling, net-positive energy production, and zero-waste operations.
The design and engineering team shared their experience tackling such a pioneering project. They believe that net-zero buildings (the project has since shifted to net positive) need to consider not only design but also operations as well. For example, in the design of the Commons Building—a combination of commercial kitchen, cafeteria, lecture halls, and classrooms—the most difficult obstacle the team faced was the design of a highly energy-efficient system. A typical EUI for a commercial kitchen is 325; the campus’s goal was to reach an average EUI of 20 in order to achieve net-zero energy with roof-mounted PVs. (EUI is a ratio of energy used per square foot, and a smaller EUI represents a lower energy usage.)
A preliminary energy model resulted in an EUI of 234, mainly due to a highly efficient envelope and geothermal heat pump system. However, the team still had a long way to go to achieve the goal of 20 EUI. Clearly the only way to truly reduce energy consumption beyond typical savings would be through a combination of ingenuity and practical changes in standard practices that involved the kitchen staff, owners, and mechanical users, among others. For instance, the engineer found that about 60 percent of energy use results from kitchen equipment, so they revised the kitchen menu to eliminate deep-fried food and provide more salad, which consumed less energy. Interestingly, healthier food actually requires less energy to prepare. After coordinating with the staff and adding more efficient equipment, they finally brought the EUI down to 97.6, a 70 percent reduction compared to a standard commercial kitchen.
When targeting net zero, design teams must convince all stakeholders of the value of these efforts in order to achieve their goals, as Mithūn did here. Now, Chathum’s Eden Hall Campus design has moved from project to lifestyle. As Peter Walker, PhD, dean of Chatham’s Falk School of Sustainability & Environment mentioned, the students committed to sustainability and even helped with the energy use feedback loop, doing the post-occupancy evaluation themselves.
WHY DESIGN MATTERS TO YOU
Another insightful session was about materials and health. When we talk about sustainable buildings, it seems common sense to say that sustainable buildings can support occupants’ health. But not until recently have scientists at Harvard proved the causal relationship between green building and human health. Joseph Allen, assistant professor of Exposure Assessment Science in the Department of Environmental Health at Harvard’s T.H. Chan School of Public Health led Cognitive Studio, a research team that conducted a series of studies on the impact of green building on cognitive function.
At first, they studied the difference between a typical office and a low-VOC green office. Their findings showed that occupants in green buildings have 61 percent higher cognitive test scores than those in typical buildings.
They then pushed further to explore any unique characteristics of green buildings compared with traditional high-ventilation buildings (also considered high performance). The primary difference was in thermal comfort—green buildings have more daylight and lower humidity. As the results showed, occupants in certified green buildings had 26 percent higher cognitive function scores, 6.4 percent higher sleep quality scores, and 30 percent fewer sick building symptoms. It is true that people are more productive in green buildings, resulting in not only higher energy efficiency but also healthier live/work environment for occupants.
When we talk about sustainable buildings, we are more likely to refer to them as energy-saving projects that use high technologies or passive design. Since sustainability has primarily been focused on energy reduction and building performance in recent years, it’s a great opportunity to learn about projects and studies that are more focused on occupants. Projects nowadays have many more choices in terms of various HVAC systems and material options, but it is time to push for occupant comfort and design high-performance projects that relates to both buildings and occupants.