Jasim M. Mahdi

Bio: Jasim M. Mahdi is an academic researcher from University of Baghdad. The author has contributed to research in topics: Phase-change material & Heat exchanger. The author has an hindex of 8, co-authored 23 publications receiving 330 citations.

Improved melting of latent heat storage via porous medium and uniform Joule heat generation

Abstract: To enhance the rate of heat transfer in phase change materials (PCM), high conductivity porous materials have been widely used recently as a promising method. This study introduces a novel approach for improving melting of PCM by incorporating uniform Joule heat generation with the porous structure compared to central heat generation. Different cases based on the heater-in foam configuration under the same heat generation rate are numerically verified and compared with the case of using the central heating element, which the heat transfer in the domain enhances by the porous medium. The effects of pore density and rate of heat generation are explored using the thermal non-equilibrium model to better deal with the interstitial heat transfer between the internal heat-generated-in-foam and the PCM. For the case with the central heating element, the effects of heater dimensions as well as the rate of heat generation are also investigated. The results show that the uniform heat generation from the porous structure can substantially reduce the melting time. Applying 100 kW/m3 for the rate of heat generation reduces the melting time by 21% compared with the best case of the localised heater. Meanwhile, applying higher pore-density foam does not bring any significant effect due to the uniform distribution of the heat generation. The results also show a small effect of localized heater size on the melting time with the same rate of heat generation density from the porous structure. However, for an identical volumetric heat source power of the localised heater, the rate of heat generation per volume is more effective compared with the heating element size due to the presence of the porous medium.

Latent thermal energy storage technologies and applications: A review

Abstract: The achievement of European climate energy objectives which are contained in the European Union's (EU) “20–20–20″ targets and in the European Commission's (EC) Energy Roadmap 2050 is possible, among other things, through the use of energy storage technologies. The use of thermal energy storage (TES) in the energy system allows to conserving energy, increase the overall efficiency of the systems by eliminating differences between supply and demand for energy. The article presents different methods of thermal energy storage including sensible heat storage, latent heat storage and thermochemical energy storage, focusing mainly on phase change materials (PCMs) as a form of suitable solution for energy utilisation to fill the gap between demand and supply to improve the energy efficiency of a system. PCMs allow the storage of latent thermal energy during phase change at almost stable temperature. The article presents a classification of PCMs according to their chemical nature as organic, inorganic and eutectic and by the phase transition with their advantages and disadvantages. In addition, different methods of improving the effectiveness of the PCM materials such as employing cascaded latent heat thermal energy storage system, encapsulation of PCMs and shape-stabilisation are presented in the paper. Furthermore, the use of PCM materials in buildings, power generation, food industry and automotive applications are presented and the modelling tools for analysing the functionality of PCMs materials are compared and classified.