Virtual calibration of a supply air temperature sensor in rooftop air conditioning units

A virtual supply airflow rate meter for rooftop air-conditioning units

“…However, this method is known to be problematic. For gas furnaces, erratic temperature measurement errors in the supply plenum exist due to non-uniform temperature distribution and intensive thermal radiation, with the resulting estimate of SCFM having a big potential spread (Wray et al 2002;Yu et al 2011). Instead, this study develops the virtual SCFM meter which utilizes newly developed low-cost virtual or virtually calibrated temperature sensors to access accurate SCFM values.…”

“…Table 6 Experimental results: Experimental results for evaluating the heating-based virtual SCFM meter are collected in Table 6 respectively. The methods to obtain the direct measurements (OAT, RAT, and sensor is innovated with good accuracy by Yu et al (2011). This method is adopted in this study and MSAT is calibrated as SAT mfr, cal in Table 4 with uncertainty ± 1.2 ºF (0.7ºC).…”

“…Due to the limitations of experimental configurations from Yu et al (2011), the correlated model of the virtual calibration method exposes greater errors (e.g., relative error is ±4.0 ˚F [2.2˚C]) under a wide range of operating conditions (e.g., OAT is lower than 35˚F[1.67˚C] and the SCFM degradation is higher than 20%) .…”

“…The existing virtual calibration model for a SAT sensor proposed by Yu et al (2011) has several deficiencies practically in the following aspects:…”

“…Experimental designs: Data used for evaluation here are adopted from the study by Yu et al (2011). Table 6 Experimental results: Experimental results for evaluating the heating-based virtual SCFM meter are collected in Table 6 respectively.…”