Investigation of phase change materials integrated with fin-tube baseboard convector for space heating

Abstract

The objective of this study was to investigate the design of a fin tube baseboard convector space heating (FBC-SH) system filled with phase change material (PCM) and analyze its performance during the melting (i.e., charging) and solidification (i.e., discharging) processes of the PCM. The effect of the orientation of the FBC-SH system on the phase change processes was also investigated to determine the thermally efficient orientation during the FBC-SH system's operation. An experimental set up was developed and detailed experimental investigations were carried out on a prototype FBC-SH system. The FBC-SH system was charged and discharged using deionized water as a heat transfer fluid (HTF) at 70 °C and 20 °C, respectively. Ten thermocouples were fixed in specified locations, and temperature readings were collected at 10 s intervals and processed. Images of melting and solidification processes were captured. Three orientations were examined: (i) vertical orientation (90°), (ii) horizontal orientation (0°), and (iii) angled orientation (45°). The graphical results of temperature variations displayed changes in temperature during the melting and solidification processes. The major observations of this study illustrated that the solidification process occurs faster than the melting process for all orientations, suggesting that the thermal energy was released at a faster rate than it can be absorbed. Due to changes in orientation of the FBC-SH chamber, height of the PCM associated with natural convection changes, the melting process occurred faster in the horizontal orientation when compared to the melting processes for the vertical and angled orientations. The horizontal orientation displayed a more even thermal energy distribution along the FBC-SH chamber compared to the angled and vertical orientations. This was observed by the melting profiles presented as images captured during the charging and discharging experiments. The charged thermal energy is higher than the discharged thermal energy. The horizontal orientation stored the greatest amount of thermal energy (295.47 kJ) and released the least amount of thermal energy (166.05 kJ). The vertical orientation stored the least amount of thermal energy (287.86 kJ) and released the greatest amount of energy (265.67 kJ) compared to the horizontal and angled orientations.