 Building Science at UC Berkeley: Research
Problem Detection in Air Handlers Edward Arens, Department of
Architecture & Director, CEDR California Institute for Energy Efficiency
The protocols we have developed consist of a set of measurement guidelines, field data collection sheets, software tools and related data analysis procedures. Included in the software tools is a fan performance database that can be used for benchmarking various fan performance metrics. It can also be used for comparing the performance of a given fan to other similar ones. Among the low-cost analysis tools being developed are: current as a proxy for power, and tracer gas airflow. Using current measured by an inexpensive current transducer (CT) instead of a power meter can reduce the cost of measurement instruments and can be safely deployed within a motor control center for the duration of the monitoring period. It has been found, however, that CTs need to be calibrated since there is significant variation in the accuracy of these devices. A significant amount of effort of this project has been devoted to development of a constant injection tracer gas (CITG) airflow monitoring technique. This technique has the potential to become a standard method of duct airflow measurements once a low-cost field deployable system is developed based on the work of this project and others. The focus of future work will be on validation testing of the protocols along with population of the fan performance database, and research to further the development of a field-ready CITG system.
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In this research we are developing
technologies that will improve energy practitioner’s ability to detect
energy related problems in built-up AHUs . To date this work has focused on
development of: 1) a consistent protocol for measurement and analysis, and
2) low-cost measurement methods. The protocols are intended to facilitate
relatively quick assessments or screening of systems to identify candidates
for retrofit projects by energy services organizations. Some of the
information being developed will also be of benefit to design professionals
by providing feedback on how actual systems perform. The methodologies we
have developed are distinct from other fault detection and diagnosis (FDD)
methods in that they rely on using short term monitoring data with a variety
of data presentation and benchmarking techniques that are focused on a
specific set of problems that commonly occur in these systems. The problems
of interest were selected because they have significant impact on energy use
and/or occupant comfort. The protocols are oriented toward constant and
variable air volume (CAV and VAV )air handling systems that are typically
found in large office and institutional buildings. For these types of
buildings fan and pump energy can use as much as 40% of total HVAC energy.