Resumen de Modeling of a heat exchanger utilizing a phase-change material for short-term storage
M.M. El-Kassaby, E. Ahmed
A computer program was proposed to simulate the behavior of a low-temperature phase-change material (PCM) in a heat exchanger for short-term storage. An experimental set-up of mainly a heat exchanger with a staggered tube arrangement and air temperature control unit were used. In the modeling approach, the PCM in the tube was divided into 10 concentric cells of equal mass, and was logically treated in terms of energy balance. Experimental inlet air temperature (at three different flow rates) was utilized as input data to test the model output results and their reliability. Excellent agreement was obtained for the outlet air temperature when compared with the experimental measurements, and differences did not exceed 0.5°C over the simulated period. The predicted PCM average temperature history showed good agreement with the experimental ones, and differences did not exceed 2° at the highest applied air flow rate. This modeling approach can be used for any PCM, provided that its thermophysical properties are available. The transient moving front for freezing or melting can be predicted, and consequently the mass fraction of either liquid or solid phase to the total PCM mass can be predicted as well.
