Detection of drifts in thermal systems based on a synchronous detection technique

• Published in: Applied thermal engineering 2011-05, Vol.31 (6), p.1135-1140
• Main Authors: Lalot, Sylvain, Andrjesdóttir, Ólöf, Desmet, Bernard
• Format: Article
• Language: English
• Subjects: Applied sciences; Convection; Discrimination; Drift; Drift detection; Electrical heater; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fouling; Heat transfer; Heat transfer coefficients; Heating equipment; Lock-in; Lumped system; Steady state; Synchronous; Synchronous detection; Theoretical studies. Data and constants. Metering; Thermal engineering
• ISSN: 1359-4311
• DOI: 10.1016/j.applthermaleng.2010.12.008

This study deals with the application of a very sensitive discrimination technique to the detection of a drift in thermal systems. After having presented the basis of the technique, the application to a lumped system shows that a decrease by 0.25% of the convection heat transfer coefficient is easily detected. To do so, the number of samples and the length of the observation have to be adjusted. It is shown that the method is powerful even if the system is not in a steady state. Finally, the method is applied to an electrical heater, and it is shown that it is possible to discriminate a mass flow decrease from the effect of fouling. ► A very sensitive drift detection technique is presented. ► In lumped systems a 0.25% decrease of the convection coefficient is easily detected. ► Powerful even if the system is not in a steady state. ► Discriminate a mass flow decrease from the effect of fouling in a heater.