Enhancements of Heat Transfer and Thermoelectric Performances Using Finned Heat-Pipe Array

Abstract

Limited improvement of thermal conductivity of phase change materials (PCMs) by flat fins has severely restricted the heat storage and release rates of PCMs. In this study, we experimentally demonstrated a new enhancement regime for both phase-change heat transfer and thermoelectric power using PCM saturated with heat-pipe array instead of traditional fins. Results indicated that the thermal structure without PCM suffered from the worst thermal-management behavior and the lowest thermoelectric power. The addition of heat-pipe array significantly enhanced the phase-change heat transfer of PCM with the wall temperature reduced by 51 ℃ compared with pure PCM. Moreover, the maximum temperature gradient along vertical and horizontal directions in PCM was less than 1.5 ℃ and 2.5 ℃ attributed to the small thermal resistance and heat transfer enhancement of heat pipes. The TEG power output with single heat pipe was almost four times larger than that with three heat pipes, whereas at the expense of increment of 20 ℃ in wall temperature. PCM convection contributed almost 20 ℃ of wall temperature drop, but also reduced the thermoelectric power. Lower wall temperature was attained by the PCM with lower phase-change point. However, the electrical power outputs from the two melting points were comparable.

Keywords: Heat transfer enhancement, Thermoelectric, Heat pipe, Phase change materials