An inverse lumped capacitance method for determination of heat transfer coefficients for industrial air blast chillers

An inverse model using lump body was developed to calculate heat transfer coefficients as a dynamic function of time. The model used sequential function specification algorithm to calculate surface heat flux from transient temperature measurements inside a lump body system. Transient temperature measurements were collected during cooling inside an industrial chiller at two different positions with different air velocities using four replicates for each position. The calculated surface heat flux was found to be very accurate as the maximum value of the root mean squares error (RMSE) for temperature is 0.045 degrees C, lower than the expected error form thermocouple measurements. The calculated heat flux was then used to calculate heat transfer coefficients as a dynamic function of cooling time followed by calculation of time average heat transfer coefficient using numerical integration. The approach developed here could be a pragmatic powerful dynamic method to model spatial variation of heat transfer coefficients for industrial chillers and freezers. (c) 2008 Elsevier Ltd. All rights reserved.