Enhancements of heat transfer and thermoelectric performances using finned heat-pipe array

Abstract

Phase change materials (PCMs) are highly promising for heat storage and passive cooling due to the combined advantages of high latent heat and selectable phase-change temperature, whereas suffer from the defect of low thermal conductivity. However, limited improvement of thermal conductivity of phase change materials (PCMs) by flat fins has severely restricted the cooling and latent heat release rates of PCMs. Moreover, previous literature has seldomly focused on the application of exhausted heat or PCM-stored latent heat. Confronted with above issues, we experimentally demonstrated a new enhancement regime for both phase-change heat transfer and thermoelectric power using PCM embedded with heat-pipe (HP) array instead of traditional fins. Results indicated that adding HP array significantly enhanced the phase-change of PCM with the wall temperature reduced by 51 ℃ compared with pure PCM. Moreover, the maximum vertical and horizontal temperature gradients were less than 1.5 ℃ and 2.5 ℃ due to the small thermal resistance of HPs. TEG power with single HP was nearly four times higher than that with three HPs, whereas at the expense of 20 ℃ increment in wall temperature. PCM convection contributed 20 ℃ of wall temperature drop, but reduced the thermoelectric power.