Sustainable Built Environment

PI: Brent Stephens (CAEE)

We spend the vast majority of our time in buildings in which we are exposed to a wide variety of indoor air pollutants of both indoor and outdoor origin. Research in this area seeks to develop and apply methods to quantify and evaluate indoor emission sources and control strategies, and to understand how changes to building design and operation influence the fate, transport, and control of indoor air pollutants such as indoor aerosols, reactive gases, and non-reactive gases. Recent projects in this area have involved quantifying sources of indoor pollutants (including outdoor pollutant infiltration; desktop 3D printers; and bioaerosols from human respiratory activities), as well as evaluating control strategies such as filtration in heating, ventilating, and air-conditioning (HVAC) systems and understanding trade-offs between energy efficiency and indoor air quality.

PI: Brent Stephens (CAEE)

Research on fundamental mechanisms that influence the fate, transport, and control of indoor pollutants necessitates continued exploration of the impacts of these mechanisms on the practice of human exposure assessment and understanding/quantifying human health risks. Research in this area primarily involves evaluating the contribution of indoor air pollutants to long-term mortality, disease burden, cancer risks, and infectious disease risks to building occupants. Recent projects in this domain have sought to understand the magnitude of human exposures to pollutants of both indoor and outdoor origin, the quantitative health impacts associated with exposures, and the extent of exposure misclassification that occurs in epidemiology studies if indoor fate, transport, and control mechanisms are not accurately accounted for.

PI: Mohammad Heidarinejad (CAEE)

Crucial to improving the sustainability of our built environment is improving energy efficiency in buildings. Research in this area seeks to conduct modeling and measurements to support policy decisions for improving energy efficiency in buildings, such as identifying cost-optimal building retrofits in existing buildings and assessing the performance of different heating, ventilation, and air-conditioning systems using numerical modeling and field experiments. Research in this area also involves modeling and measurements to understand the energy implications of improvements to thermal comfort or indoor air quality in buildings, or conversely, the comfort and indoor air quality implications of improvements to energy efficiency and sustainability in buildings.

PI: Brent Stephens (CAEE)

Critical to understanding building operation is the widespread deployment of environmental sensors. This research area focuses on the development, evaluation, and application of inexpensive open-source building environmental sensors. A recent project in this area is the Open Source Building Science Sensors (OSBSS) project (http://osbss.com), which developed an Arduino-based platform for building arrays of inexpensive, open-source sensors and data loggers designed to reduce the costs of recording long-term building environmental and operational measurements while also improving capabilities and functionality beyond commercially available tools. Wireless sensors have been designed and built to measure air temperature and relative humidity, surface environmental conditions, CO2 concentrations, human occupancy and location proximity, illuminance levels, and more.

PI: David Arditi (CAEE)

The construction industry negatively impacts the global environment and depletes natural resources. To promote sustainability in the construction industry, many organizations have introduced guidelines and rating systems for buildings, one of which is Leadership in Energy and Environmental Design (LEED), the most globally acknowledged system. Although LEED excels in reducing the negative environmental impacts and the energy consumption of buildings, the high costs associated with the implementation and pursuit of LEED certification are pushing away some project owners from entering the process. To balance the conflicting objectives of LEED points and construction costs, a multi-objective optimization framework is developed that uses Non-Dominated Sorting Genetic Algorithm-II (NSGA-II) for construction projects pursuing LEED v4 BD+C certification in new construction. The optimization is performed using a BIM-designed project and confirms the efficiency and soundness of the model. The results show that the method does indeed lead to optimal solutions.

PI: David Arditi (CAEE)

Constructing according to green principles rather than traditional methods poses a new set of risks to project participants. These risks should be appropriately identified and managed in order to prevent cost overruns. Construction risks should be identified and their cost impacts in Leadership in Energy and Environmental Design (LEED)-certified projects should be assessed. Research indicates that the risks associated with consultant, contractor, and subcontractor issues have the highest expected impact on costs. The top five risk factors are contractors and subcontractors agreeing to standards that are not within their expertise and competence; high cost of certification; lack of expertise in new products/technologies; doubts about the long-term viability and performance of new and untested products, materials, and technologies; inadequate definition of project parties’ contractual roles and responsibilities. Mitigating the cost impact of risks is of great value to owners, designers, and contractors. Recognizing the risks associated with LEED-certified projects and their cost impacts can be of benefit to all practitioners.

PI:  David Arditi (CAEE)

Compared to other categories, the Energy and Atmosphere category contributes the most to the maximum obtainable points in the Leadership in Energy and Environmental Design (LEED) certification system. The extent to which project teams take advantage of the credits in the Energy and Atmosphere category of LEED needs to be explored. The performance of practitioners in achieving points in the Energy and Atmosphere credits of LEED NC 2009 are analyzed for 1,500 buildings that received LEED certification in the United States. For a better understanding of the credit patterns, the differences in the performance of practitioners are investigated relative to certification levels and project ownership. Practitioners who recognize these priorities and differences are expected to be better positioned to make sustainability-related decisions in building design and construction.