Experimental and computational study of phase change material based shell and tube heat exchanger for energy storage

Abstract

The storage of thermal energy is an important issue that needs to be addressed. The wastage of heat energy, such as in an automobile or thermal power plant exhausts, means the loss of useful heat energy that could have been reused considering the present energy crisis scenario. The Phase Change Material (PCM) plays one such role in harnessing, storing, and reusing the waste heat energy. These materials have a unique property of changing their phase from solid to liquid whenever some heat energy is provided to them. It utilizes a latent heat storage method at a fairly constant temperature. In the present study, the shell and tube heat exchanger (HE) with thermal energy storage containing PCM (a mixture of organics) is tested for its heat storage capability. This PCM changes its phase at approximately 58 °C to 65 °C, and its operating range is 60 °C to 70 °C. The Performance of heat exchanger is investigated for a single round of temperatures for both charging and discharging cycles. The simulation has carried out to study the melting characteristics of PCM using ANSYS fluent. During the charging cycle, the heat energy stored in the PCM is 458.23 kJ for a duration of 100 min whereas, heat given by PCM material to the water during discharging cycle is 316.008 kJ for a duration of 50 min. It can be concluded that heat energy which is stored in the HE can be extracted effectively and used for suitable applications which operate at reasonably high temperatures.