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Embedded Intelligence in Buildings Program

The Embedded Intelligence in Buildings (EIB) Program seeks to develop and deploy advances in measurement science that will improve building operations to achieve lower operating costs, higher energy efficiency, and occupant comfort, safety, and security through the use of intelligent building systems.¹ The project topics related to this mission include building operational improvements to achieve energy efficiency while enhancing occupant comfort and safety, developing intelligent agent approaches for control of complex building systems, improving building commissioning and functional performance tests, integrating with intelligent electricity grids, building management system interoperability, and fault detection and diagnostics for building systems.

The EIB Program resides within the Energy and Environment Division (EED) of the NIST Engineering Laboratory (EL). Some EIB Program staff members work in the Smart Grid Office and are not part of the EED. The EED supports about 51 technical staff members. The EIB Program operates with an annual budget of $3.4 million, of which approximately 10 percent is supported from the NIST Smart Grid Office and the remainder from the EED. Staffing has not had a net change in the past 5 years, as new hires are offset by retirements and departures.

Intelligent controls for heating, ventilation, and air conditioning (HVAC) are an area of rapid growth within the broader HVAC market, expected to reach a global value of about $33 billion by 2026.² The potential economic impact of advances in embedded building intelligence is enormous, since HVAC accounts for about 50 percent of residential energy use³ and 44 percent of commercial building energy use.⁴ The issues have national importance, since survey information has reported that more than 90 percent of residential HVAC systems are operating with at least one fault and that even more fail basic diagnostics because of flow restrictions or incomplete installations.⁵

On a global scale, the 2018 Intergovernmental Panel on Climate Change report noted that in 2010 buildings accounted for 32 percent of total global energy use, 19 percent of greenhouse gas (GHG) emissions, and up to one-third of fluorinated gases.⁶ Energy use and emissions from the building sector

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¹ Embedded Intelligence in Buildings Program description is available at http://www.nist.gov/programsprojects/embedded-intelligence-buildings-program.

²GlobeNewsWire, 2020, “HVAC Controls Market to Expand with 12.2% CAGR through 2026,” http://www.globenewswire.com/news-release/2020/06/16/2048592/0/en/HVAC-controls-market-to-expand-with-122-CAGR-through-2026.html.

³ U.S. Energy Information Administration (EIA), 2015, “Energy Use in Homes,” https://www.eia.gov/energyexplained/use-of-energy/homes.php.

⁴ EIA, 2012, “Commercial Buildings Energy Consumption Survey (CBECS),” 2012 data, Table E1, http://www.eia.gov/consumption/commercial/data/2012/c&e/cfm/e1.php.

⁵ J.P. Proctor, 2004, “Residential and Small Commercial Central Air Conditioning; Rated Efficiency Isn’t Automatic,” ASHRAE Winter Meeting.

⁶ O. Lucon, D. Ürge-Vorsatz, A. Zain Ahmed, H. Akbari, P. Bertoldi, L.F. Cabeza, N. Eyre, et al., 2014, “Buildings,” Chapter 9 in Climate Change 2014: Mitigation of Climate Change, Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, UK, and New York, NY, http://www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5_chapter9.pdf.

could double or triple by 2050 unless trends are changed. Section 433 of the Energy Independence and Security Act (HR 6, December 2007) requires that all new federal buildings and major renovations meet the energy performance standards of the “2030 Challenge” beginning in 2010. The 2030 Challenge proposes that all new buildings, developments, and major renovations shall be carbon-neutral by 2030.⁷ This move toward net-zero energy (NZE) and high-performance buildings and communities is an important motivator of the NIST program.

Given the huge stock of existing buildings, many cities are establishing “Tune-Up” mandates⁸ to require periodic retro-commissioning of commercial buildings larger than about 5,000 m^2. As the NIST team pointed out, in most cases energy reduction links to improved occupant comfort, as systems are adjusted to perform to their design targets. Although sophisticated building automation systems are used in large commercial buildings in the United States to manage HVAC systems, the NIST team reported that most buildings are not properly commissioned, operated, or maintained. External studies suggest that over 30 percent of annual primary energy consumed in today’s U.S. commercial buildings could be saved with fully functional advanced controls.⁹ Existing buildings and emerging high-performance buildings require accurate sensing, effective use of existing controls, deployment of advanced controls, and enhancement with embedded intelligence. Associated technologies include embedded automated fault detection and diagnostics (AFDD) for building systems, automated continuous commissioning of building systems, fault-tolerant controls, and effective user interfaces are essential for strong national-scale impact.

Building integration of renewable energy is another major trend. Intelligent buildings with integrated renewable resources (photovoltaic solar panels, for example) offer an opportunity to link the control of loads, small-scale storage, and renewable resources into combined “grid friendly” end use. The challenge for architects and building systems designers is how to develop system-level concepts for more effective energy management. Interconnection of renewable energy is based primarily on power electronic inverters, with fast dynamic control but no inherent inertia. Several studies have shown that inverter droop controls can mitigate undesired dynamic impacts on the grid, provided there is some energy headroom or storage.^10,11 Electric vehicles offer possible storage resources when integrated into a building system with vehicle-to-grid (V2G) interfaces.

A building itself has the potential to act as large-scale thermal storage, since the thermal time constants have scales of minutes or hours. Storage can be added intentionally with extra mass, such as ice, or by integrating hot water systems into energy management. A motor in an HVAC system, for example, can be controlled on millisecond time scales. Altering fan speeds or turning heaters or coolers on and off can implement fast dynamic load management, potentially offsetting rapid variations of solar resources.¹² It is clear that energy elements and sources in a building (e.g., electrical, water, gas, oil, and solar) as well as building operations need to be measurable and controllable. At a campus or community level, concepts

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⁷ See Architecture 2030, “The 2030 Challenge,” https://architecture2030.org/2030_challenges/2030-challenge.

⁸ See, for example, City of Seattle, “OSE Building Tune-Ups Ordinance,” http://www.seattle.gov/Documents/Departments/OSE/OSE%20Building%20Tune-Ups%20ORD.pdf; City of New York, “Energy Audits and Retro-Commissioning,” http://www.nyc.gov/html/gbee/html/plan/ll87.shtml; City of Philadelphia, Bill No. 190600, https://www.imt.org/wp-content/uploads/2020/02/Final-legislationCertifiedCopy19060001.pdf.

⁹ N. Fernandez, W. Katipamula, W. Wang, Y. Xie, and M. Zhao, 2018, Energy savings potential from improved building controls for the US commercial building sector, Energy Efficiency 11(2): 393-413, https://doi.org/10.1007/s12053-017-9569-5.

¹⁰ P.J. Hart, R.H. Lasseter, and T.M. Jahns, 2019, Coherency identification and aggregation in grid-forming droop-controlled inverter network, IEEE Transactions in Industry Applications 55(3): 2219-2231, doi: 10.1109/TIA.2019.2891555.

¹¹ M. Sinha, F. Dörfler, et al., 2017, Uncovering droop control laws embedded within the nonlinear dynamics of Van der Pol oscillators, IEEE Transactions in Control of Network Systems 4(2): 347-358, doi: 10.1109/TCNS.2015.2503558.

¹² H. Hao, Y. Lin, et al., 2014, Ancillary service to the grid through control of fans in commercial building HVAC systems, IEEE Transactions in Smart Grid 5(4): 2066–2074.

of building energy integration can be expanded. Mitigation of dynamic imbalance between supply and demand will require more sophisticated algorithms to coordinate operations with the electric grid. This is an important opportunity for standards and measurement, especially directed at interoperability.

TECHNICAL MERIT OF THE PROGRAM

Accomplishments

The NIST EIB team has been recognized with several major awards that affirm their leading contributions to intelligent building controls. The dominant professional organization related to the program is the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). A staff member received the 2017 ASHRAE Standards Achievement Award.¹³ This is one example of this program’s major role in emerging standards for high-performance building. Several other team members have received industry-related awards or Department of Commerce leadership recognition. The NIST team’s work on BACnet verifies their global leadership. BACnet, the building automation and control network protocol that has become ASHRAE/ANSI Standard 135, and standard ISO 16484-5, which enables disparate building systems to exchange information.

The NIST team’s publications and products include major contributions such as HVACSIM+, the “HVAC SIMulation PLUS other systems” computation tool.¹⁴ The NIST Data Alignment Tool helps users analyze building system fault and commissioning information.¹⁵ The current research on failure detection and diagnostics is leading new directions for industry and has strong promise for positive impact on building system performance and energy reduction. The industry engagement on these programs is strong and foundational to projects in building performance.

The work on semantic interoperability for intelligent buildings is excellent and paves a path toward an exciting future for the EL and for the early-career personnel running the project. The work on smart-grid integration and on fault detection and diagnostics is ongoing. These important projects need to be integrated into a long-term strategic plan. The nation clearly benefits from NIST as the premier global organization for testing and measurement. The enormous impact of buildings and the built environment makes the EIB program and its planning and personnel a vital national investment likely to have large-scale returns.

Challenges and Opportunities

The EIB program information did not present a well-formed strategic pathway to ensure that projects and personnel are part of a larger multidisciplinary path toward common goals for intelligent buildings. Many projects appeared to be initiated in an ad hoc manner, contributing to the program mission but with limited inter-project cohesion. Projects need to build synergy to guarantee relevance, timeliness, and the ability to lead industry toward 21st century intelligent building excellence. There was limited evidence of rigorous metrics and assessment of individual projects relative to overall program goals. The evidence presented seemed to rely on conventional academic metrics such as technical publications, conference papers, and service to technical organizations. While these are an important

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¹³ ASHTAE, 2017, “ASHRAE Celebrates Contributions, Achievements of More than 100 Members at the 2017 Long Beach Annual Conference,” http://www.ashrae.org/about/news/2017/ashrae-celebrates-contributionsachievements-of-more-than-100-members-at-the-2017-long-beach-annual-conference.

¹⁴ NIST, 2020, “HVAC SIMulation PLUS Other Systems (HVACSIM+),” http://www.nist.gov/servicesresources/software/hvac-simulation-plus-other-systems-hvacsim.

¹⁵ The tool is available to the public at NIST, “The NIST Data Alignment Tool,” updated June 18, 2019, http://www.nist.gov/services-resources/software/nist-data-alignment-tool.

starting point, metrics are needed to establish impact on industry practices and on rapid and widespread adoption of effective intelligent building systems. NIST needs to articulate a long-term strategic plan to make sure that the spectrum of projects remains strong and bold and fits into a larger roadmap for intelligent buildings.

Given the modest program budget and project portfolio, wide impact is difficult to achieve, but Americans spend more than 90 percent of their time in buildings, and effective building systems have large-scale quality-of-life impacts. The program has an opportunity to articulate the large return on investment for the full range of EIB goals. Basic objectives such as establishing interoperability practices and programs for industry can help restore U.S. leadership in building systems technology and equipment. The impact is immense. The extreme return on investment will help communicate the opportunities and the urgency.

PORTFOLIO OF SCIENTIFIC EXPERTISE

Accomplishments

The EIB programs as presented by the NIST team showed strong expertise and overall technical excellence. The individual projects were well thought out and executed competently. The principal investigators were goal-driven and had specific, clear deliverables for each project. A concern is limited evidence of a unifying strategic plan to ensure coordination and cross-fertilization of present and future projects.

Challenges and Opportunities

NIST EL has an opportunity to make sure that the entire spectrum of projects and personnel feeds into a long-term vision. The laboratory has established a formal mentoring program, which appears to be having strong positive impact. There are several areas in which informal collaboration across NIST has been beneficial. There is an opportunity to encourage more formal collaboration. For many projects, it was observed that relevant expertise resides beyond the EED.

The Intelligent Building Agents Laboratory (IBAL) is state of the art and employs advanced technology, although there was a clear shortage of personnel and long-term resources to support potential long-range strategic directions. Many key personnel were transient or short-term employees, such as postdoctoral researchers or term assignees. This revealed a need for personnel pipeline planning to bring in, sustain, and support a diverse workforce. This diverse workforce will benefit from well-defined career paths to guarantee successful matriculation of key personnel at NIST. Given the relatively low turnover at NIST—generally an advantage—a clear plan to grow, train, and support early-career hires is essential. Along these lines, the NIST EL has established a formal mentoring program for its new hires, but it could expand the impact of this activity. The mix of the later- and earlier-career researchers is advantageous, but some of the interactions seem incidental with no planned structure. A more experience-diverse workforce will yield a more diverse set of solutions that will foster and present new solutions to challenging problems.

ADEQUACY OF RESOURCES

Accomplishments

The EIB program has developed several unique national laboratory resources for high-performance buildings. The new IBAL has set up a rigorous measurement environment for building

systems and devices. One of its strengths is the ability to perform reproducible tests under nearly any plausible operating condition. The facility can simulate exterior weather through control of temperature, moisture, and other factors. It can evaluate, in depth, the performance of devices or controls.

The program has access to the Net-Zero Energy House (NZE House). In contrast to more conventional test houses at various locations, the NIST NZE House is set up for careful, highly reproducible, testing and measurement. In the renewable energy arena, the lack of reproducible test conditions and consistent measurement methods have been barriers to progress. The thorough scientific approach at NIST confirms their global leadership in rigorous science-driven data generation and analysis.

Challenges and Opportunities

Thermal and environmental test chambers are crucial tools for evaluation and testing at the device and subsystem level. Facilities such as IBAL and the NZE House are exceptional tools for large-scale system tests, but they are not intended to support quicker evaluation and analysis of components or subsystems. The existing chambers for this purpose are dated and do not support the range of necessary tests and measurements. Enhancement of these aspects of laboratory infrastructure is vital to support strong national impact.

A few relevant national laboratories within the Department of Energy (DOE) portfolio, notably the National Renewable Energy Laboratory (NREL) and the Pacific Northwest National Laboratory (PNNL), have equipment-intensive work related to renewable energy integration, intelligent electricity grids, and building-integrated renewable energy. The EIB program might be able to take advantage of some related facilities, bringing NIST’s unparalleled excellence in test and measurement to bear on projects that could return high-impact results suitable for NIST. The team has the opportunity to explore potential collaborations, including collaborations with universities.

DISSEMINATION OF OUTPUTS

Accomplishments

The EIB Program personnel and project work is known and respected in the professional community. Products such as software tools and models are available to the public and effectively supported by the NIST team. BACnet in particular is a dissemination highlight, with wide adoption in industry and substantial impact. The program disseminates many of its activities through technical publications and journal articles. The research productivity is on par with other leading laboratory programs.

Challenges and Opportunities

As of 2012, the United States has more than 5.6 million commercial buildings.¹⁶ Microsoft has created a building outline database with more than 125 million entries.¹⁷ A major challenge is that architects, builders, owners, occupants, and other end users often have disparate objectives for building systems and their operation. In residences, occupants have primary control. The growth of consumer intelligent tools such as Nest thermostats suggests that user-friendly interfaces with informative feedback

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¹⁶ U.S. Energy Information Administration, 2012, Commercial Buildings Energy Consumption Survey (CBECS), http://www.eia.gov/consumption/commercial/reports/2012/buildstock/.

¹⁷ Microsoft, 2020, “US Building Footprints,” http://github.com/microsoft/USBuildingFootprints.

can have profound impact on building operation and performance. NIST has an opportunity to influence end-user interfaces, standardize data collection and reporting, and inform citizens about high-performance building systems and the benefits of commissioning. There is an opportunity for the EIB program to seek a variety of ways to inform consumers and develop outreach materials to disseminate useful information to the public.

CONCLUSIONS AND RECOMMENDATIONS

Technical Merit of the Program

The NIST EIB Program demonstrates global leadership in measurement science and its application to building operations and to intelligent building systems. This small program has outsized impact because of leadership on BACnet, on fault detection and diagnostics (FDD) tools, and on validation of intelligent building controls.

Efforts in intelligent and high-performance buildings and building systems require years or even decades of consistent effort. Although successful outcomes from the individual projects will advance the mission and vision of the EL, strategic thinking and planning to support long-term efforts is critical and essential.

Intelligent building operations reach beyond temperature and indoor air quality management; operations also include lighting quality, acoustics and noise, active energy management, and the whole range of issues directed to improved human productivity and quality of life. Emerging issues include pathogen monitoring and mitigation, active noise reduction, daylight emulation, and others.

Effectiveness of Dissemination of Outputs

In intelligent building systems, the industry continues to rely on proprietary interfaces and has provided limited interoperability beyond basic data exchange from BACnet. The lack of interoperability of building devices and systems is a serious threat to U.S. industry. As competitors in Europe, Korea, and other places introduce more open-source interoperable systems, they are likely to overtake U.S. vendors with closed systems quickly. Communication networks and protocols, including BACnet, have limits on dynamic interoperability. For example, IEC 61850, although developed in a different context (utility substations), seeks fast data exchange for real-time intelligent grid operation. Comprehensive interoperability is being explored in health care contexts.¹⁸

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¹⁸ M. Glickman and A. Orlova, 2020, “Building Interoperability Standards and Ensuring Patient Safety,” American Health Information Management Association, http://bok.ahima.org/doc?oid=107799#.X38RIe17m70.

Several U.S. national laboratories are currently pursuing research and development in intelligent buildings and intelligent electricity grids. The EIB program has an opportunity to interface with facilities and projects in certain DOE national laboratories, notably the grid interface and renewable energy work at NREL and the transactive energy work at PNNL. The EL is engaged with some efforts at relevant national laboratories, but there is an opportunity to strengthen this interaction. The NIST team has the opportunity to raise the level of data-driven work at relevant national laboratories, at the same time benefiting from collaboration in some DOE facilities.

Broader adoption of AFDD and “grid friendly” features in building systems and appliances will have significant impact in improving operating efficiency and reducing operating costs. Factory installation of these features rather than retrofitting after they are built will reduce cost, enhance reliability, promote interoperability, and set a more level playing field for these vital features. Integration of grid interfaces into these will be required to balance energy generation and usage in the future. It would also be worthwhile to explore the economics of control element retrofitting.

Dissemination of critical outcomes, best practices for building systems, for guidance about preventative maintenance, and for other information is critical to the success of the program and for greater impact. Given the massive installed base of residential buildings, homeowners and other occupants can play a critical role in intelligent building operation.

This is best done in coordination with other federal agencies (for example, the DOE and EPA are active in this area also). Without coordination, the end result would duplicate work done in different ways.