RTU, FDD, fault, performance, degradation
In this paper, the results of lab and field evaluation of several RTU FDD technologies will be presented and discussed.Â The focus the study was on RTUs that provide cooling of small and medium commercial buildings. This work was conducted by UTRC in close collaboration Purdue University within Consortium for Building Energy Innovation (CBEI). The goal of the lab activity was to engineer and assess low-cost, embeddable fault detection and diagnostics (FDD) for a new RTU product that exceeds DOE's High Performance RTU performance specification. Primary focus of evaluation was on overall unit performance degradation (COP and capacity) resulted from single and multiple operational faults. High confidence and low false alarm rate of COP degradation were demonstrated. The cost effectiveness of FDD will be discussed. Due to high interest and close engagement of Original Equipment Manufacturer (OEM) and National Account Customer field evaluation of FDD became possible. Several commercial sited with state-of-the-art RTUs were instrumented for continues monitoring of RTU performance and assessment of frequency of typical operational faults. Also some operational faults are intentionally injected in order evaluate FDD effectiveness. Several levels of FDD applicable in the field will be discussed.