Novel Simplified Approach for the Thermal Characterisation of Triple Tube Heat Exchangers.

To assess the performance of triple tube heat exchangers, it is not possible to apply the traditional methods (e.g., Wilson plot method) because they can be only applied to the classical shell-in-tube configuration that can be easily modelled by the logarithmic mean temperature difference approach. Therefore, to overcome this limitation, some new methodologies have been proposed in the literature and, among them, a promising tool is represented by the parameter estimation procedure. Parameter estimation procedure is a powerful technique already adopted in many engineering applications. However, this procedure requires, for the application investigated in the present study, a detailed numerical model of the triple tube heat exchanger and the measurement of the temperature of the fluids in each tube at inlet and outlet sections. These elements make its application feasible only in well-equipped research labs, limiting its massive employment in industrial facilities. In this paper, a novel parameter estimation procedure to characterize the thermal behavior of the triple concentric-tube heat exchanger is proposed. This approach is based on a simple model of the exchanger and it requires to measure the fluid temperature only in four sections. The simplified proposed procedure is numerically validated and compared to the full one. [ABSTRACT FROM AUTHOR]