“Towards Net Zero Energy High Performance Buildings”
Dr. Zheng O’Neill, United Technologies Research Center
Building energy consumption is approximately 40% of the total U.S. energy use. The Department of Energy established a goal to create the technology and knowledge base for net zero energy (NZE) commercial and residential buildings by 2025. The proposed NZE buildings will use 70% less energy relative to ASHRAE 90.1-2004 and generate the remaining 30% onsite. There are two major issues: how to create a new generation of NZE and carbon-neutral buildings, and how to operate buildings to achieve design intent and optimal status. High-performance buildings typically do not operate as designed because of a diverse set of particular inefficiencies. Commissioning case studies typically show a 10-20% reduction in building site energy consumption and peak demand.
This talk discusses a building energy conservation strategy that uses remote monitoring and ongoing commissioning. The presented remote monitoring system operates with existing or upgraded building energy management and control systems (EMCS). The real-time data is transmitted to a database through the building network on an ongoing basis. Data is captured, stored and analyzed with data mining and physics model-based methods in an integrated information system. This system is used to 1) identify equipment and system performance degradation, 2) support classification and identification of deviation root causes, 3) provide and prioritize corrective actions and 4) quantify the energy savings. Physics model-based fault detection and diagnostics was demonstrated for remote monitoring and ongoing commissioning of building mechanical and energy systems. Application examples from the equipment and subsystem level include an AHU (air-handling unit) economizer and an AHU schedule created with real-time data extracted from building EMCS. Since some performance metrics are not measured or cannot be measured, system inversion and data assimilation techniques are introduced into the analysis process. For example, a zonal load estimator can detect localized faults such as envelope leaks or unexpected equipment heat gains. Finally, a simulation based study for NZE supermarket design will be discussed to demonstrate energy savings associated with NZE techniques.
Zheng O’Neill is a staff research engineer and principal investigator in the System Design and Integration Group at United Technologies Research Center in East Hartford, Conn. Her expertise is in building technology covering integrated building energy and control systems design, modeling, simulation and optimization, building commissioning, real-time decision support systems in buildings for fault detection and diagnostics, and low energy/net zero energy buildings. She received her PhD in mechanical engineering from Oklahoma State University in 2004. She currently serves as a technical committee member for ASHRAE TC 7.5 smart building systems and TC1.5 computer applications. She is an active member of ASHRAE and the International Building Performance Simulation Association.