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Commissioning Building Systems for Improved Energy Performance Project

Summary:

Building systems commissioning processes applied at the design phase and throughout the building life cycle have been shown to effectively improve performance and reduce energy consumption. In spite of that fact, commissioning is underutilized because current practices are labor intensive and require considerable technical expertise. NIST will develop the measurement science needed to enable commissioning techniques that leverage the embedded capabilities of building automation and control systems to automate functional performance tests and analyze the results in ways that reduce costs, and incorporate the improvements into high impact industry best practice guidelines.

Description:

Objective: To improve the operating efficiency of building systems by 10 % to 30 % by providing the measurement science needed to develop improved building commissioning techniques that utilize embedded capabilities of building control systems, and accelerate the adoption of cost effective commissioning as standard practice.

What is the new technical idea? Past NIST work has resulted in the development of a software commissioning tool, HVACCx, with the capability of interfacing with BACnet building automation systems, running test scripts that command the control system into specific modes of operation, and then collect and analyze data to determine system performance. NIST recently partnered with ASHRAE to convene a group of industry commissioning experts to identify additional measurement science gaps that inhibit effective commissioning practices. That effort uncovered a need to test and verify design sequences of operation in addition to mechanical equipment faults, and a need to provide building owners guidance about the relative economic impact of problems that are identified. ASHRAE recently published a set of standard sequences of operation for use in a variety of building HVAC system designs. The new technical idea is to leverage these new standard sequences of operation and the capabilities of the HVAC-Cx tool to develop a library of automated commissioning tests linked to the standard sequences of operation. This work can become the basis for new industry guidelines or standard methods of test for building system commissioning. In addition, NIST will develop a prototype rating system to provide the metrics needed to inform building owners/operators about how best to invest their limited resources in resolving problems that are identified in the commissioning process.

What is the research plan? NIST will use the Virtual Cybernetic Building Testbed (VCBT) to implement the ASHRAE standard sequences of operation including both normal operation and commonly found faults. Using the VCBT as a laboratory test building, automated commission tests will be developed and evaluated. Field trials will be conducted by a local building commissioning firm and a local college to confirm laboratory results and evaluate the usability of the tools. NIST will also develop a method to characterize the productivity and energy consumption impact of faults that can be incorporated into both HVAC-Cx and the FDDEA fault detection and diagnostic tool under development in a separate research project in the Embedded Intelligence in Buildings program.

Technology transfer will be achieved by continued interaction with industry throughout the development process to establish market pull for our research products as well as efforts to disseminate valuable research results to a wider audience (market push) through informative journal publications, involvement in the development of key industry guidelines (ASHRAE Guideline 36P High Performance Sequences of Operation for HVAC Systems, ASHRAE Guideline 1.2 Commissioning Process for Existing HVAC&R Systems) and educational activities such as webinars and tool demonstrations.

Major Accomplishments:

Improved Energy Efficiency of Operations:

  • Completed IEA Annex 40, Commissioning of Building HVAC Systems for Improving Energy Performance and IEA Annex 47, Cost Effective Commissioning for Existing and Low Energy Buildings. These international collaborations established benchmark guidance for current commissioning practices and identified key areas were improvement is needed. (FY 2010)
  • CITE-AHU tool for automated commissioning of air-handling units. This software tool significantly reduces the workload for commissioning air-handling units increasing the likelihood that this important activity will be more widely adopted. (FY 2011)
  • DASH database, a national repository of triple bottom line building performance data enabling the consistent collection of quantitative data about green, sustainable, and high performance buildings and facilitating reporting and analysis based on that information. (FY 2013)