Commissioning Building Systems for Improved Energy Performance

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. The results will be used to improve high-impact industry best-practice guidelines.

Description

Objective - To improve the operating efficiency of building systems 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, HVAC-Cx, 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 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 has published Guideline 36, High Performance Sequences of Operations for HVAC Systems. The new technical idea is to leverage these new recommended sequences of operation and the capabilities of the HVAC-Cx tool to develop and validate a library of automated commissioning tests linked to the standard sequences of operation. This validation work can become the basis for new industry guidelines or standard methods of test for building system commissioning tools. 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?
Research efforts will focus on measurement science needs identified by the Industry Roadmapping Workshop.  Functional performance tests for the ASHRAE Guideline 36 sequence of operations will be developed and implemented in the HVAC-Cx tool.  The Virtual Cybernetic Building Testbed (VCBT) will be configured to represent a variety of HVAC system designs appropriate for applying the Guideline 36 sequence of operation.  Using the VCBT as a laboratory test building, automated commission tests will be developed and evaluated under normal conditions and with a variety of common HVAC system faults. Field trials will also be conducted with a local building commissioning firm and a local college to confirm laboratory results and evaluate the usability of the tools. 

A method to characterize the energy consumption and life-cycle impact of faults will be developed and incorporated into HVAC-Cx in collaboration with the Engineering Laboratory Office of Applied Economics.  To assist the building industry in applying the knowledge gained from commissioning commercial buildings to energy-efficient residences, NIST will leverage experience gained in building and operating the Net Zero Energy Residential Test Facility to develop and document recommended best practices for commissioning high-performance residential buildings and testing the performance of their systems.

The NIST Engineering Laboratory will work with industry throughout the development process to establish market pull for our research products. Research results will be disseminated to a wider audience (market push) through informative journal publications, involvement in the development of key industry guidelines (ASHRAE Guideline 36 - 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.  Steps will also be taken to make NIST-developed tools and the guidance for using them readily-available online.

Major Accomplishments

Outcome

• CITE-AHU tool for automated commissioning of air-handling units
• 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.
• Publication "Building Commissioning Research and Measurement Science Roadmap Webinar Workshop

Potential Impact

• HVAC-Cx automated commissioning tool for AHUs, chillers, and VAV boxes