• Energy Research

Abstract This paper reports the results of a numerical study on the heat transfer during process of conduction dominated solidification of copper–water nanofluid in isosceles trapezoidal cavity under controlled temperature and concentration gradients. The suspended nanoparticles have proven to increase the heat transfer rate substantially. The horizontal walls of the cavities are insulated while side walls are kept at constant but different temperatures. The total solidification time of pure fluid and nanofluid filled in the cavity is investigated for three different inclinations of side walls and the results are compared with square cavity. Results revealed that the total solidification time for pure fluid as well for nanofluid for all nano particle concentrations decreases. The effects of Grashof number (105–107) on the heat transfer phenomenon and solid–liquid interface are also numerically investigated and presented graphically. The enthalpy–porosity technique is used to trace the solid–liquid interface. Inclination angle can be used efficiently to control the solidification time. In addition, average Nusselt number along the hot wall for different angles, nanoparticles volume fractions, and Grashof number is presented graphically. The proposed predictions are very helpful in developing improved latent heat thermal energy storage for solar heat collector and for casting and mold design.

Abstract This paper reports the results of a numerical study on the heat transfer during process of conduction dominated solidification of copper–water nanofluid in isosceles trapezoidal cavity under controlled temperature and concentration gradients. The suspended nanoparticles have proven to increase the heat transfer rate substantially. The horizontal walls of the cavities are insulated while side walls are kept at constant but different temperatures. The total solidification time of pure fluid and nanofluid filled in the cavity is investigated for three different inclinations of side walls and the results are compared with square cavity. Results revealed that the total solidification time for pure fluid as well for nanofluid for all nano particle concentrations decreases. The effects of Grashof number (105–107) on the heat transfer phenomenon and solid–liquid interface are also numerically investigated and presented graphically. The enthalpy–porosity technique is used to trace the solid–liquid interface. Inclination angle can be used efficiently to control the solidification time. In addition, average Nusselt number along the hot wall for different angles, nanoparticles volume fractions, and Grashof number is presented graphically. The proposed predictions are very helpful in developing improved latent heat thermal energy storage for solar heat collector and for casting and mold design.

Abstract Thermal energy can be stored in the form of latent heat as well as in the form of sensible heat energy. Latent heat storage is preferred over the sensible heat storage because of its higher storage density and almost constant temperature for melting and solidifying processes. This paper reports a comprehensive review of previous work on various eutectic organic phase change materials for thermal energy storage purposes in the form of latent heat. This includes development of binary and ternary eutectic mixtures of organic phase change materials. The various thermal properties of the phase change materials for heat storage are also reviewed in this paper. This also includes thermal properties enhancement technique for organic eutectic PCMs. Form stable nature of PCMs is a very effective way of storing thermal energy without getting any leakage issue. So, this review also presents eutectic material based form stable PCMs. hence, this review paper can serve as a reference for eutectic organic PCMs and their thermal properties.

Abstract Thermal energy can be stored in the form of latent heat as well as in the form of sensible heat energy. Latent heat storage is preferred over the sensible heat storage because of its higher storage density and almost constant temperature for melting and solidifying processes. This paper reports a comprehensive review of previous work on various eutectic organic phase change materials for thermal energy storage purposes in the form of latent heat. This includes development of binary and ternary eutectic mixtures of organic phase change materials. The various thermal properties of the phase change materials for heat storage are also reviewed in this paper. This also includes thermal properties enhancement technique for organic eutectic PCMs. Form stable nature of PCMs is a very effective way of storing thermal energy without getting any leakage issue. So, this review also presents eutectic material based form stable PCMs. hence, this review paper can serve as a reference for eutectic organic PCMs and their thermal properties.

Abstract Thermal energy storage (TES) properties of form-stabilized Sepiolite(Sep)/Fatty acid eutectic composite PCM(FAEM) and temperature control performance of its cement based-plaster in laboratory scale were investigated. The eutectic mixture of capric acid(CA) and stearic acid(SA) recognized as FAEM was infiltrated by Sep by direct impregnation method. The Sep/FAEM(42%) composite PCM developed in stabilized form was characterized by SEM, FTIR and XRD analysis techniques. The DSC results exhibits that the produced form-stabilized composite PCM (FSt-CPCM) had proper melting temperature (22.86 °C) and relatively high latent heat capacity (76.16 J/g) for thermal regulation targets of building spaces. The FSt-CPCM showed outstanding chemical stability and TES reliability although it was exposed to 1000 melt/freeze cycles. In addition, cement plaster containing FSt-CPCM exhibited appreciated temperature control performance in laboratory scaled-test room compared to ordinary cement plaster. It was concluded from this finding that the produced Sep/FAEM/Cement composite plaster can be evaluated a beneficial material for indoor temperature regulation and energy saving in building envelopes.

Abstract Thermal energy storage (TES) properties of form-stabilized Sepiolite(Sep)/Fatty acid eutectic composite PCM(FAEM) and temperature control performance of its cement based-plaster in laboratory scale were investigated. The eutectic mixture of capric acid(CA) and stearic acid(SA) recognized as FAEM was infiltrated by Sep by direct impregnation method. The Sep/FAEM(42%) composite PCM developed in stabilized form was characterized by SEM, FTIR and XRD analysis techniques. The DSC results exhibits that the produced form-stabilized composite PCM (FSt-CPCM) had proper melting temperature (22.86 °C) and relatively high latent heat capacity (76.16 J/g) for thermal regulation targets of building spaces. The FSt-CPCM showed outstanding chemical stability and TES reliability although it was exposed to 1000 melt/freeze cycles. In addition, cement plaster containing FSt-CPCM exhibited appreciated temperature control performance in laboratory scaled-test room compared to ordinary cement plaster. It was concluded from this finding that the produced Sep/FAEM/Cement composite plaster can be evaluated a beneficial material for indoor temperature regulation and energy saving in building envelopes.

Abstract Phase change materials (PCMs) utilized for thermal energy storage applications are verified to be a promising technology due to their larger benefits over other heat storage techniques. Apart from the advantageous thermophysical properties of PCM, the effective utilization of PCM depends on its life span. Moreover, PCMs which are utilized for different solar thermal energy storage applications are required longer thermal and chemical stability for the extended performance of a system. This review shows the in-depth details on thermal stability and reliability of different PCMs such as organic, inorganic, eutectics, and composites materials for heat storage applications. Different methods for measuring the thermophysical properties along with the classification of PCMs based on applications and temperature ranges have been discussed. This paper also covers the selection criteria and commercial viability of PCMs for different domestic and industrial applications. In addition to this, the effect of thermal cycle testing on the properties of different organic, inorganic, eutectic, and composite PCMs has been summarized. The present article can be highly useful for researchers and practice engineers in the areas related to thermal energy storage applications.