To develop and deploy advances in measurement science that will improve building operations to achieve lower operating costs, energy efficiency, and occupant comfort, safety and security through the use of intelligent building systems.
What is the problem?
“The world is facing twin energy related threats: that of not having adequate and secure supplies of energy at affordable prices and that of environmental harm caused by consuming too much of it” . Any successful response to these threats must consider buildings. Buildings account for 40% of the United States’ energy use, more than the transportation or industrial sectors . The Energy Independence and Security Act of 2007 established a national goal of achieving net-zero energy buildings by 2030. Industry groups including the American Institute of Architects (AIA), the Association of Home Appliance Manufacturers (AHAM), and the Air-Conditioning, Heating, and Refrigeration Institute (AHRI) have established similar or compatible goals. In order to meet these goals, it is essential that the efficiency of building operations be significantly improved.
Approximately 84% of the life cycle energy use of a building is associated with operating the building rather than the materials and energy used for construction . “Building systems almost never achieve their design efficiencies at any time during building operation and their performance typically degrades over time” . As the Nation proceeds with developing a new smart grid and increasing the use of intermittent renewable energy sources, buildings occupants will need access to actionable energy consumption information and building systems will need to become collaborative partners in maintaining the stability and reliability of the grid.
In addition to energy issues, building operation practices face pressure to improve safety, security, and occupant comfort and health. Building control companies, equipment and system manufacturers, energy providers, utilities, and design engineers are under increasing pressure to improve performance and reduce costs by developing building systems that integrate more and more building services, including energy management, fire and security, vertical transportation, fault detection and diagnostics, optimal control, the real time purchase of electricity, and the aggregation of building stock. Measurement science is lacking to enable these systems to have the intelligence to communicate, interact, share information, make decisions, detect and respond to faults, and perform in a synergistic and reliable manner. Specific needs include standard data models, communication protocols, user interface standards, security procedures, testing tools, and performance metrics. Overcoming these barriers is critical if building systems are to meet these operational needs and if the U.S. is to obtain a significant share of the developing world wide market for such systems.
What is the technical idea?
The new idea is to address the measurement science needs of cybernetic building systems in a holistic, integrated manner that considers complex system interactions and their impact on energy consumption, comfort, safety, security, and maintenance. Measurement science is needed that will:
- Lead to enhancements in communication protocol standards that enable the practical use of integrated HVAC, lighting, security, vertical transport, energy management, and emergency response systems to achieve increased comfort, safety, and energy efficiency;
- Support a laboratory testbed capable of whole building emulation of normal operation and a variety of faulty and hazardous conditions suitable for evaluating the needs and performance of cybernetic building systems in identifying and responding to equipment failures and abnormal conditions;
- Enable more energy efficient building operation through development of information models and software tools that improve the design and commissioning process and embedded intelligence in building control systems that can detect and respond to problems and optimize the control and performance of building systems; and
- Enable secure real-time communication of building system information to outside parties such as interconnection of building automation and control systems with a future smart utility grid.
What is the research plan?
The research plan consists of a portfolio of interrelated projects that focus on key areas of measurement science needed to achieve successful development and implementation of cybernetic building systems. Collectively they provide a comprehensive approach that will lead to new industry standards and practices which will result in a radical market transformation in building system design and operation.
Two unique laboratories play a critical role in this research program. One is the Virtual Cybernetic Building Testbed (VCBT). This realistic, whole-building emulator combines actual building control equipment with simulated building systems and weather. The VCBT is used by projects in the program to conduct research under controlled conditions that cannot be accomplished in actual buildings. The second laboratory is the Intelligent Building Agents Laboratory (IBAL). The IBAL is a complex "building in a laboratory" that includes all of the mechanical equipment that would typically be found in a small office building, as well as equipment to deliver conditions and thermal loads that are consistent with this application. The IBAL support research in the use of artificial intelligence to optimize the building-scale performance of mechanical systems.
This program also provides technical support for the ongoing development of key enabling standards that create the communication infrastructure used in the VCBT and upon which embedded intelligent systems will be built. EL’s past work has led to international adoption and commercialization of BACnet, one of the most widely used and successful standards in ASHRAE history. EL will continue to work with industry partners to enhance BACnet capabilities in ways that eliminate barriers to extending BACnet beyond HVAC applications and enable BACnet systems to provide operational data to enterprise management tools. A second generation HVACSIM+ dynamic building simulation program is also being developed that will significantly reduce the time and expertise needed to develop complex simulation models.
Commissioning Building Systems for Improved Energy Performance is a project intended to address the problem that building automation systems are rarely commissioned and are poorly maintained, resulting in operational issues that increase cost, and reduce occupant comfort and productivity. The commissioning research builds on interactions with ASHRAE technical committees and industry partners, past international collaborations through the International Energy Agency, and the development of the NIST HVAC-Cx commissioning tool. Future efforts will focus on expanding the capabilities of HVAC-Cx by developing automated test scripts for verifying that control systems correctly implement ASHRAE defined sequences of operation and by determining the effectiveness of these tests using both the VCBT and field trials. A method will also be developed to characterize the impact of faults on energy consumption and occupant comfort in order to guide users in prioritizing their maintenance activities and repairs.
Two projects address automated fault detection and diagnostics (FDD) for HVAC system components. One focuses on residential systems and one on commercial building systems. Both projects involve developing and testing FDD tools that can be implemented using commercially available instrumentation and control products, and demonstrating the energy benefits of detecting and responding to faults before building conditions degrade to the point that occupants complain. In the residential area research will focus on FDD for heat pumps and air conditioners. This involves testing a NIST-developed adaptive FDD algorithm under real-world transient conditions, laboratory tests to collect well-characterized system performance data under multiple simultaneous faults, and continuing technical support for the development of standards and tools to evaluate the performance of FDD algorithms. For commercial building systems, the work will focus on collaborating with CRADA partners for continued development and field testing of a Fault Detection and Diagnostic – Expert Assistant (FDD-EA) in HVAC and compressed air system applications, expanding the interactive diagnostic capabilities of the tool, and developing a way to prioritize faults based on energy impact and occupant comfort.
A research project on control optimization using intelligent agents seeks to enable a fundamental paradigm shift in the way in which building system operation is optimized for energy efficiency. Classical optimization techniques have not been successful in buildings, but adapting machine learning and intelligent agent technology from other fields offers the promise of significant improvement in building operations. The IBAL serves as a resource for this effort to develop and test a range of intelligent agent-based optimization approaches.
Cybernetic building systems involve communication and interaction with entities outside the building as well as within. Research in the Building Integration with the Smart Grid project targets improving and expanding consumer access to their energy usage information through standards promoted by the Green Button Alliance, leading industry research in exploring the viability of a range of transactive energy approaches, and activities that support the development of key standards for building-to-grid integration identified in the NIST Smart Grid Roadmap. Research is also underway to develop new control strategies for building electrical load management that is responsive to needs of the smart grid and tools to evaluate the performance of control algorithms in a smart grid environment.