Occupancy and vacancy sensors have been widely adopted in buildings to save energy. However, the lack of a fully described, technology-agnostic occupancy-sensor test method that yields reproducible results across different implementations has been a barrier to the commercialization of such technologies.
Newer sensor technologies have the potential to improve occupancy detection and offer new capabilities, such as measuring traffic in a space or discerning different object types. Toward the goal of a more accurate test method that would capture new and emerging sensor capabilities, researchers at Pacific Northwest National Laboratory (PNNL) conducted a literature review of test methods for characterizing occupancy sensor performance. The review, conducted on behalf of the U.S. Department of Energy Lighting R&D Program, summarized test conditions for indoor sensors and identified apparent test-method improvements needed to evaluate emerging technologies and products. This information will inform the development of a technology-agnostic occupancy-sensor test method that more accurately represents performance in buildings.
Two active (i.e., not deprecated) fully described test methods and 33 research studies containing ad hoc test methods were examined. Both fully described test methods were primarily developed to characterize the performance of predominant market-available and deployed products, comprising a single sensing device that utilizes passive infrared (PIR) and/or ultrasonic technology intended to be installed in and to monitor a single, defined area.
The research studies encompassed a total of six sensor technologies: air quality; industrial, scientific, and medical band radiofrequency; infrared; mechanical; other radio frequencies; and visible light. None of the test methods were capable of evaluating all five temporal properties (presence, count, location, track, and identity) and stimulating all five states of presence (major motion, minor motion, hand motion, stillness, and absence). While most of the research studies were more focused on characterizing a specific occupancy-sensor technology than on defining a test method, this review yielded a wide variety of unique test conditions.
Given the growing number of technologies being developed and adapted for the detection of occupancy, as well as their increasing success in discerning spatiotemporal properties beyond presence, the development of test methods that are more capable, replicable, and fully described appears warranted, according to the study authors. They suggest that future research leverage the unique test conditions identified in their review toward the development of a technology-agnostic, fully described test method for characterizing emerging occupancy sensors.
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