Simulación de un intercambiador de calor para almacenamiento de energía térmica mediante el uso de materiales de cambio de fase : Simulación de un intercambiador de calor de tubos y coraza para el almacenamiento de energía térmica de alta temperatura.

Abstract

Simulation has become a fundamental technique to reproduce and analyze behaviors without the need to bring them to reality. This is very useful in the engineering field. In the present work, the simulation of a shell and tube heat exchanger with potassium carbonate as phase change material (PCM) to store thermal energy from combustion gases (charge) with the objective of preheating air for the combustion process (discharge) was carried out, for which a computational fluid dynamics program was used, where ANSYS Fluent was selected as the simulation program through literature review and tests of use. Subsequently, the geometry of the heat exchanger was built based on the sizing performed in the curricular integration work presented by Quishpe (2022), the computational meshing was performed, the initial and boundary conditions were configured, and finally the simulation was started in the same program. The geometry of a shell and tube heat exchanger consisting of 24 tubes, 8 baffles and two passes through the shell was made, and an unstructured mesh consisting of 279233 nodes and a quality of 0.82 was obtained. With what was obtained in the unloading process a preheated air at 1203.2 K with a 75% phase change of solidification in 8 h. It was also determined that if the mass flow of the air is increased to triple the original value, a phase change of 88% of the PCM is obtained. For the loading process, a 99.7% melting phase change was obtained in 16 h, with a power yield of 35.80 kW. It was also determined that for the charging process the heat exchange time could be reduced to 12 h without significantly affecting the phase change. Both processes obtained residual values that make the simulation reliable. Experimental tests are recommended to verify the results.